Journal articles: '38 GHz propagation measurement'

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Hossain, Ferdous, Tan Geok, Tharek Rahman, Mhd Hindia, Kaharudin Dimyati, and Azlan Abdaziz. "Indoor Millimeter-Wave Propagation Prediction by Measurement and Ray Tracing Simulation at 38 GHz." Symmetry 10, no. 10 (2018): 464. http://dx.doi.org/10.3390/sym10100464.

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The Millimeter-Wave (mmW) technology is going to mitigate the global higher bandwidth carriers. It will dominate the future network system by the attractive advantages of the higher frequency band. Higher frequency offers a wider bandwidth spectrum. Therefore, its utilizations are rapidly increasing in the wireless communication system. In this paper, an indoor mmW propagation prediction is presented at 38 GHz based on measurements and the proposed Three-Dimensional (3-D) Ray Tracing (RT) simulation. Moreover, an additional simulation performed using 3-D Shooting Bouncing Ray (SBR) method is presented. Simulation using existing SBR and the proposed RT methods have been performed separately on a specific layout where the measurement campaign is conducted. The RT methods simulations results have been verified by comparing with actual measurement data. There is a significant agreement between the simulation and measurement with respect to path loss and received signal strength indication. The analysis result shows that the proposed RT method output has better agreement with measurement output when compared to the SBR method. According to the result of the propagation prediction analysis, it can be stated that the proposed method’s ray tracing is capable of predicting the mmW propagation based on a raw sketch of the real environment.

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Gulfam, Sardar, Syed Nawaz, Konstantinos Baltzis, Abrar Ahmed, and Noor Khan. "Characterization of Fading Statistics of mmWave (28 GHz and 38 GHz) Outdoor and Indoor Radio Propagation Channels." Technologies 7, no. 1 (2019): 9. http://dx.doi.org/10.3390/technologies7010009.

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Extension of usable frequency spectrum from microwave to millimeter-wave (mmWave) is one of the key research directions in addressing the capacity demands of emerging 5th-generation communication networks. This paper presents a thorough analysis on the azimuthal multipath shape factors and second-order fading statistics (SOFS) of outdoor and indoor mmWave radio propagation channels. The well-established analytical relationship of plain angular statistics of a radio propagation channel with the channel’s fading statistics is used to study the channel’s fading characteristics. The plain angle-of-arrival measurement results available in the open literature for four different outdoor radio propagation scenarios at 38 GHz, as well as nine different indoor radio propagation scenarios at 28 GHz and 38 GHz bands, are extracted by using different graphical data interpretation techniques. The considered quantifiers for energy dispersion in angular domain and SOFS are true standard-deviation, angular spread, angular constriction, and direction of maximum fading; and spatial coherence distance, spatial auto-covariance, average fade duration, and level-crossing-rate; respectively. This study focuses on the angular spread analysis only in the azimuth plane. The conducted analysis on angular spread and SOFS is of high significance in designing modulation schemes, equalization schemes, antenna-beams, channel estimation, error-correction techniques, and interleaving algorithms; for mmWave outdoor and indoor radio propagation environments.

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Al-Samman, Ahmed M., Marwan Hadri Azmi, Y. A. Al-Gumaei, et al. "Millimeter Wave Propagation Measurements and Characteristics for 5G System." Applied Sciences 10, no. 1 (2020): 335. http://dx.doi.org/10.3390/app10010335.

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In future 5G systems, the millimeter wave (mmWave) band will be used to support a large capacity for current mobile broadband. Therefore, the radio access technology (RAT) should be made available for 5G devices to help in distinct situations, for example device-to-device communications (D2D) and multi-hops. This paper presents ultra-wideband channel measurements for millimeter wave bands at 19, 28, and 38 GHz. We used an ultra-wideband channel sounder (1 GHz bandwidth) in an indoor to outdoor (I2O) environment for non-line-of-sight (NLOS) scenarios. In an NLOS environment, there is no direct path (line of sight), and all of the contributed paths are received from different physical objects by refection propagation phenomena. Hence, in this work, a directional horn antenna (high gain) was used at the transmitter, while an omnidirectional antenna was used at the receiver to collect the radio signals from all directions. The path loss and temporal dispersion were examined based on the acquired measurement data—the 5G propagation characteristics. Two different path loss models were used, namely close-in (CI) free space reference distance and alpha-beta-gamma (ABG) models. The time dispersion parameters were provided based on a mean excess delay, a root mean square (RMS) delay spread, and a maximum excess delay. The path loss exponent for this NLOS specific environment was found to be low for all of the proposed frequencies, and the RMS delay spread values were less than 30 ns for all of the measured frequencies, and the average RMS delay spread values were 19.2, 19.3, and 20.3 ns for 19, 28, and 38 GHz frequencies, respectively. Moreover, the mean excess delay values were found also at 26.1, 25.8, and 27.3 ns for 19, 28, and 38 GHz frequencies, respectively. The propagation signal through the NLOS channel at 19, 28, and 38 GHz was strong with a low delay; it is concluded that these bands are reliable for 5G systems in short-range applications.

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Rubio, Lorenzo, Vicent M. Rodrigo Peñarrocha, Marta Cabedo-Fabres, et al. "Millimeter-Wave Channel Measurements and Path Loss Characterization in a Typical Indoor Office Environment." Electronics 12, no. 4 (2023): 844. http://dx.doi.org/10.3390/electronics12040844.

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In this paper, a path loss characterization at millimeter-wave (mmWave) frequencies is performed in a typical indoor office environment. Path loss results were derived from propagation channel measurements collected in the 25–40 GHz frequency band, in both line-of-sight (LOS) and obstructed-LOS (OLOS) propagation conditions. The channel measurements were performed using a frequency-domain channel sounder, which integrates an amplified radio over fiber (RoF) link to avoid the high losses at mmWave. The path loss was analyzed in the 26 GHz, 28 GHz, 33 GHz and 38 GHz frequency bands through the close-in free space reference distance (CI) and the floating-intercept (FI) models. These models take into account the distance dependence of the path loss for a single frequency. Nevertheless, to jointly study the distance and frequency dependence of the path loss, multi-frequency models were considered. The parameters of the ABG (A-alpha, B-beta and G-gamma) and the close-in free space reference distance with frequency path loss exponent (CIF) models were derived from the channel measurements in the whole 25–40 GHz band under the minimum mean square error (MMSE) approach. The results show that, in general, there is some relationship between the model parameters and the frequency. Path loss exponent (PLE) values smaller than the theoretical free space propagation were obtained, showing that there are a waveguide effect and a constructive interference of multipath components (MPCs). Since the measurements were obtained in the same environment and with the same configuration and measurement setup, it is possible to establish realistic comparisons between the model parameters and the propagation behavior at the different frequencies considered. The results provided here allow us to have a better knowledge of the propagation at mmWave frequencies and may be of interest to other researchers in the simulation and performance evaluation of future wireless communication systems in indoor hotspot environments.

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Majed, Mohammed Bahjat, Tharek Abd Rahman, Omar Abdul Aziz, Mohammad Nour Hindia, and Effariza Hanafi. "Channel Characterization and Path Loss Modeling in Indoor Environment at 4.5, 28, and 38 GHz for 5G Cellular Networks." International Journal of Antennas and Propagation 2018 (September 20, 2018): 1–14. http://dx.doi.org/10.1155/2018/9142367.

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The current propagation models used for frequency bands less than 6 GHz are not appropriate and cannot be applied for path loss modeling and channel characteristics for frequency bands above 6 GHz millimeter wave (mmWave) bands, due to the difference of signal propagation characteristics between existing frequency bands and mmWave frequency bands. Thus, extensive studies on channel characterization and path loss modeling are required to develop a general and appropriate channel model that can be suitable for a wide range of mmWave frequency bands in its modeling parameter. This paper presents a study of well-known channel models for an indoor environment on the 4.5, 28, and 38 GHz frequency bands. A new path loss model is proposed for the 28 GHz and 38 GHz frequency bands. Measurements for the indoor line-of-sight (LOS) and non-line-of-sight (NLOS) scenarios were taken every meter over a separation distance of 23 m between the TX and RX antenna locations to compare the well-known and the new large-scale generic path loss models. This measurement was conducted in a new wireless communication center WCC block P15a at Universiti Teknologi Malaysia UTM Johor, Malaysia, and the results were analyzed based on the well-known and proposed path loss models for single-frequency and multifrequency models and for directional and omnidirectional path loss models. Results show that the large-scale path loss over distance could be modeled better with good accuracy by using the simple proposed model with one parameter path loss exponent PLE (n) that is physically based to the transmitter power, rather than using the well-known models that have no physical base to the transmitted power, more complications (require more parameters), and lack of anticipation when explaining model parameters. The PLE values for the LOS scenario were 0.92, 0.90, and 1.07 for the V-V, V-H, and V-Omni antenna polarizations, respectively, at the 28 GHz frequency and were 2.30, 2.24, and 2.40 for the V-V, V-H, and V-Omni antenna polarizations, respectively, at the 38 GHz frequency.

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Hao Xu, T. S. Rappaport, R. J. Boyle, and J. H. Schaffner. "Measurements and models for 38-GHz point-to-multipoint radiowave propagation." IEEE Journal on Selected Areas in Communications 18, no. 3 (2000): 310–21. http://dx.doi.org/10.1109/49.840191.

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B. Majed, Mohammed, Tharek A. Rahman, and Omar Abdul Aziz. "Propagation Path Loss Modeling and Outdoor Coverage Measurements Review in Millimeter Wave Bands for 5G Cellular Communications." International Journal of Electrical and Computer Engineering (IJECE) 8, no. 4 (2018): 2254. http://dx.doi.org/10.11591/ijece.v8i4.pp2254-2260.

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The global bandwidth inadequacy facing wireless carriers has motivated the exploration of the underutilized millimeter wave (mm-wave) frequency spectrum for future broadband cellular communication networks, and mmWave band is one of the promising candidates due to wide spectrum. This paper presents propagation path loss and outdoor coverage and link budget measurements for frequencies above 6 GHz (mm-wave bands) using directional horn antennas at the transmitter and omnidirectional antennas at the receiver. This work presents measurements showing the propagation time delay spread and path loss as a function of separation distance for different frequencies and antenna pointing angles for many types of real-world environments. The data presented here show that at 28 GHz, 38 GHz and 60 GHz, unobstructed Line of Site (LOS) channels obey free space propagation path loss while non-LOS (NLOS) channels have large multipath delay spreads and can utilize many different pointing angles to provide propagation links. At 60 GHz, there is more path loss and smaller delay spreads. Power delay profiles PDPs were measured at every individual pointing angle for each TX and RX location, and integrating each of the PDPs to obtain received power as a function of pointing angle. The result shows that the mean RMS delay spread varies between 7.2 ns and 74.4 ns for 60 GHz and 28 GHz respectively in NLOS scenario.

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Mohammed, B. Majed, A. Rahman Tharek, and Abdul Aziz Omar. "Propagation Path Loss Modeling and Outdoor Coverage Measurements Review in Millimeter Wave Bands for 5G Cellular Communications." International Journal of Electrical and Computer Engineering (IJECE) 8, no. 4 (2018): 2254–60. https://doi.org/10.11591/ijece.v8i4.pp2254-2260.

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The global bandwidth inadequacy facing wireless carriers has motivated the exploration of the underutilized millimeter wave (mm-wave) frequency spectrum for future broadband cellular communication networks, and mmWave band is one of the promising candidates due to wide spectrum. This paper presents propagation path loss and outdoor coverage and link budget measurements for frequencies above 6 GHz (mm-wave bands) using directional horn antennas at the transmitter and omnidirectional antennas at the receiver. This work presents measurements showing the propagation time delay spread and path loss as a function of separation distance for different frequencies and antenna pointing angles for many types of real-world environments. The data presented here show that at 28 GHz, 38 GHz and 60 GHz, unobstructed Line of Site (LOS) channels obey free space propagation path loss while non-LOS (NLOS) channels have large multipath delay spreads and can utilize many different pointing angles to provide propagation links. At 60 GHz, there is more path loss and smaller delay spreads. Power delay profiles PDPs were measured at every individual pointing angle for each TX and RX location, and integrating each of the PDPs to obtain received power as a function of pointing angle. The result shows that the mean RMS delay spread varies between 7.2 ns and 74.4 ns for 60 GHz and 28 GHz respectively in NLOS scenario.

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Nossire, Zyad, Navarun Gupta, Laiali Almazaydeh, and Xingguo Xiong. "New Empirical Path Loss Model for 28 GHz and 38 GHz Millimeter Wave in Indoor Urban under Various Conditions." Applied Sciences 8, no. 11 (2018): 2122. http://dx.doi.org/10.3390/app8112122.

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Due to rapid development in mobile communication technology in recent years, the demand for high quality and high capacity networks with thorough coverage has become a major necessity. Several models have been developed for predicting wireless signal coverage in urban areas, but these models suffer from inadequately calculating certain conditions, such as weather and building materials, especially window size. In this paper, we propose a new path loss prediction model based on the measurement of new indicators, such as window size, temperature, and humidity conditions, after which an extensive statistical analysis using a linear regression technique was implemented in order to validate the new indicators. As the new indicators were incorporated into the Okumura model to derive a new path loss model, the results showed that the proposed model provides an accurate prediction of the received signal strength in a given propagation environment. Our model enhanced the prediction of path loss by 10% when compared to the Okumura and by 15% when compared to the COST-Hata.

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Shen, Yuyan, Yu Shao, Liao Xi, Heng Zhang, and Jie Zhang. "Millimeter-Wave Propagation Measurement and Modeling in Indoor Corridor and Stairwell at 26 and 38 GHz." IEEE Access 9 (2021): 87792–805. http://dx.doi.org/10.1109/access.2021.3081822.

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Asma, Ali Budalal, Md Rafiqul Islam, Hadi Habaebi Mohamed, and Abd. Rahman Tharek. "The effects of rain fade on millimetre wave channel in tropical climate." Bulletin of Electrical Engineering and Informatics 8, no. 2 (2019): 653–64. https://doi.org/10.11591/eei.v8i2.1487.

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The main objective of this paper to determine multipath and time-varying channel behaviour of short-terrestrial millimetre-wave point-to-point radio links. In an attempt to invigorate the impact of rain attenuation on mm-wave channel parameters such as the RMS delay spread, path loss received power strength and Rician distribution with a K factor. A brief analysis of rain fading was presented based on the simultaneous measurement of one-minute rain rate and its effects on a short experimental link of 38 GHz. Rain fade average is observed as high as 16 dB for 300 m path at about 125 mm/hr rain intensity. The statistical spatial channel mode (SSCM) simulation software was utilized for an operating frequency of 38 GHz. To generate of power delay profile (PDP). For both omnidirectional and directional antenna. The RMS delay spread and path loss has been estimated using the environmental parameters of Kuala Lumpur city which illustrates the theoretical performances of 5G in Malaysia. It is observed that RMS delay spread, path loss received power strength and K factor effected dramatically by rain fade. (SSCM) simulation software has to be modified to consider rain fade dynamic characteristics to achieve ultra-reliability requirements of outdoor applications in the tropical regions. This study is important for understanding signal propagation phenomena in short distance and enabling the utilization of the millimetre wave band for an urban micro-cellular environment for 5G communication system.

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Oladimeji, Tolulope T., Pradeep Kumar, and Mohamed K. Elmezughi. "Performance analysis of improved path loss models for millimeter-wave wireless network channels at 28 GHz and 38 GHz." PLOS ONE 18, no. 3 (2023): e0283005. http://dx.doi.org/10.1371/journal.pone.0283005.

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The importance of the path loss in millimeter wave channel propagation cannot be taken for granted in terms of deployment, design, performance assessment, and planning. The path loss helps to determine the network’s geographic coverage. Although many path loss models, including statistical and empirical models based on measurement and linear regression, have been proposed by various researchers, high fidelity is required to determine the performance of the wireless network’s channel. This research validates the improved version of the well-known close in (CI) and floating intercept (FI) path loss models at frequency bands of 28 and 38 GHz. The measurement surroundings comprised of an enclosed passageway with vertical-horizontal (V-H) and vertical-vertical (V-V) antenna polarizations. One of the key findings of this study is that the enhanced versions of these models typically perform better in terms of consistency than the standard models thereby justifying their high accuracy level. The improved versions of the CI and the FI models demonstrate a significant improvement for various antenna polarizations. The mean prediction error (MPE) and standard deviation error (SDE) also show how precisely and accurately the improved models predict the path loss. Additionally, the improved models provide the reasonable responsiveness and uniformity of the parameters with the change in the antenna polarization and lower the shadow fading’s standard deviation in LOS as well as NLOS situations. The results confirm that the modified versions of CI and FI models predict path loss better in an enclosed environment for 5G networks.

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Ibraheem, A. Shayea, A. Alkhawaldeh Salim, A. Nisirat Mahdi, A. Rahman Tharek, and Ergen Mustafa. "Channel fading attenuation based on rainfall rate for future 5G wireless communication system over 38-GHz." International Journal of Electrical and Computer Engineering (IJECE) 12, no. 5 (2022): 5104–13. https://doi.org/10.11591/ijece.v12i5.pp5104-5113.

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In this paper, the effect of heavy rainfall on the propagation of a 38-GHz in a tropical region was studied and analyzed. Real measurement was collected, with a path length of 300 meters, for a (5G) radio linkage in Malaysia, installed at the Universiti Teknologi Malaysia (UTM) Johor Bahru campus. The employed system entails an Ericsson MINI-Link 38 E-0.6 mm, with a horizontal polarization (HP) antenna at the top integrated with a rain gauge and a data logger. Daily registered samples with a single minute span, for a full study period of 1 month, were collected and evaluated. The obtained rain rate was found as 56 mm/hr with a specific rain attenuation of 18.4 dB/km for 0.01% of the time. In addition to that, a calculated average rain attenuation of 5.5 dB for the transmission path of 300 meters length, was calculated. Based on these findings, a recommendation to update the International Telecommunication Union (ITU) specification of the rain attenuation for Malaysia is proposed. Based on the results, we suggest shifting the zone classification of Malaysia from zone P to zone N-P. Therefore, accurate design for future 5G systems would rely on more precise estimated attenuation levels leading to enhanced performance.

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Al-samman, Ahmed M., Tharek Abd Rahman, and Marwan Hadri Azmi. "Indoor Corridor Wideband Radio Propagation Measurements and Channel Models for 5G Millimeter Wave Wireless Communications at 19 GHz, 28 GHz, and 38 GHz Bands." Wireless Communications and Mobile Computing 2018 (2018): 1–12. http://dx.doi.org/10.1155/2018/6369517.

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This paper presents millimeter wave (mmWave) measurements in an indoor environment. The high demands for the future applications in the 5G system require more capacity. In the microwave band below 6 GHz, most of the available bands are occupied; hence, the microwave band above 6 GHz and mmWave band can be used for the 5G system to cover the bandwidth required for all 5G applications. In this paper, the propagation characteristics at three different bands above 6 GHz (19, 28, and 38 GHz) are investigated in an indoor corridor environment for line of sight (LOS) and non-LOS (NLOS) scenarios. Five different path loss models are studied for this environment, namely, close-in (CI) free space path loss, floating-intercept (FI), frequency attenuation (FA) path loss, alpha-beta-gamma (ABG), and close-in free space reference distance with frequency weighting (CIF) models. Important statistical properties, such as power delay profile (PDP), root mean square (RMS) delay spread, and azimuth angle spread, are obtained and compared for different bands. The results for the path loss model found that the path loss exponent (PLE) and line slope values for all models are less than the free space path loss exponent of 2. The RMS delay spread for all bands is low for the LOS scenario, and only the directed path is contributed in some spatial locations. For the NLOS scenario, the angle of arrival (AOA) is extensively investigated, and the results indicated that the channel propagation for 5G using high directional antenna should be used in the beamforming technique to receive the signal and collect all multipath components from different angles in a particular mobile location.

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Al-Samman, Ahmed, Tharek Rahman, MHD Hindia, Abdusalama Daho, and Effariza Hanafi. "Path Loss Model for Outdoor Parking Environments at 28 GHz and 38 GHz for 5G Wireless Networks." Symmetry 10, no. 12 (2018): 672. http://dx.doi.org/10.3390/sym10120672.

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It has been widely speculated that the performance of the next generation Internet of Things (IoT) based wireless network should meet a transmission speed on the order of 1000 times more than current wireless networks; energy consumption on the order of 10 times less and access delay of less than 1 ns that will be provided by future 5G systems. To increase the current mobile broadband capacity in future 5G systems, the millimeter wave (mmWave) band will be used with huge amounts of bandwidth available in this band. Hence, to support this wider bandwith at the mmWave band, new radio access technology (RAT) should be provided for 5G systems. The new RAT with symmetry design for downlink and uplink should support different scenarios such as device to device (D2D) and multi-hop communications. This paper presents the path loss models in parking lot environment which represents the multi-end users for future 5G applications. To completely assess the typical performance of 5G wireless network systems across these different frequency bands, it is necessary to develop path loss (PL) models across these wide frequency ranges. The short wavelength of the highest frequency bands provides many scatterings from different objects. Cars and other objects are some examples of scatterings, which represent a critical issue at millimeter-wave bands. This paper presents the large-scale propagation characteristics for millimeter-wave in a parking lot environment. A new physical-based path loss model for parking lots is proposed. The path loss was investigated based on different models. The measurement was conducted at 28 GHz and 38 GHz frequencies for different scenarios. Results showed that the path loss exponent values were approximately identical at 28 GHz and 38 GHz for different scenarios of parking lots. It was found that the proposed compensation factor varied between 10.6 dB and 23.1 dB and between 13.1 and 19.1 in 28 GHz and 38 GHz, respectively. The proposed path loss models showed that more compensation factors are required for more scattering objects, especially at 28 GHz.

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Manhal, Alhilali, Ghanim Mustafa, Din Jafri, and Yin Lam Hong. "A methodology for precise estimation of rain attenuation on terrestrial millimetre wave links from raindrop size distribution measurements." TELKOMNIKA Telecommunication, Computing, Electronics and Control 17, no. 5 (2019): 2139–46. https://doi.org/10.12928/TELKOMNIKA.v17i5.12798.

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Attenuation by atmospheric rain is the most significant impairment in millimetre wave frequencies (mmWave). Modern instruments could provide detailed measurements of rain, such as raindrop size distributions (DSDs). The analysis of DSDs could estimate their effects on past or co-located links measurements. This study presents propagation analysis in the mmWave bands using measurements of two terrestrial links working at 26 GHz and 38 GHz carried out in Johor, Malaysia. Statistics obtained have been analysed in detail to extract any excess attenuation. The DSDs provided by a disdrometer have been used to estimate rain attenuation. The derived results show that the estimation can provide reasonable accuracy after extracting the wet antenna effects and having the advantage of the availability of measurements from various types of equipment.

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Al-Samman, Ahmed Mohammed, Tharek Abd Rahman, Marwan Hadri Azmi, and Samir A. Al-Gailani. "Millimeter-wave propagation measurements and models at 28 GHz and 38 GHz in a dining room for 5G wireless networks." Measurement 130 (December 2018): 71–81. http://dx.doi.org/10.1016/j.measurement.2018.07.073.

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Shayea, Ibraheem A., Salim A. Alkhawaldeh, Mahdi A. Nisirat, Tharek A. Rahman, and Mustafa Ergen. "Channel fading attenuation based on rainfall rate for future 5G wireless communication system over 38-GHz." International Journal of Electrical and Computer Engineering (IJECE) 12, no. 5 (2022): 5104. http://dx.doi.org/10.11591/ijece.v12i5.pp5104-5113.

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In this paper, the effect of heavy rainfall on the propagation of a 38-GHz in a tropical region was studied and analyzed. Real measurement was collected, with a path length of 300 meters, for a (5G) radio linkage in Malaysia, installed at the Universiti Teknologi Malaysia (UTM) Johor Bahru campus. The employed system entails an Ericsson MINI-Link 38 E-0.6 mm, with a horizontal polarization (HP) antenna at the top integrated with a rain gauge and a data logger. Daily registered samples with a single minute span, for a full study period of 1 month, were collected and evaluated. The obtained rain rate was found as 56 mm/hr with a specific rain attenuation of 18.4 dB/km for 0.01% of the time. In addition to that, a calculated average rain attenuation of 5.5 dB for the transmission path of 300 meters length, was calculated. Based on these findings, a recommendation to update the International Telecommunication Union (ITU) specification of the rain attenuation for Malaysia is proposed. Based on the results, we suggest shifting the zone classification of Malaysia from zone P to zone N-P. Therefore, accurate design for future 5G systems would rely on more precise estimated attenuation levels leading to enhanced performance.

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Sydorchuk, O. L., V. P. Маnoilov, N. N. Karashchuk, and V. G. Parfeniuk. "Research of Dispersion Characteristics of a Rectangular Waveguide with a Corrugated Bottom Wall by the Coupled Wave Method." Visnyk NTUU KPI Seriia - Radiotekhnika Radioaparatobuduvannia, no. 86 (September 30, 2021): 29–38. https://doi.org/10.20535/radap.2021.86.29-38.

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The research on dispersive characteristics of a rectangular waveguide with the goffered bottom wall a method of the connected waves is presented.Rectangular and round waveguides with the goffered walls usually are used in a superhigh-frequency range as band-pass and low-pass filters, irradiators of multiband mirror aerials of satellite communication; in radar-tracking gauges of a W-range for detection and creation of cards of space garbage, etc. Definition of a constant of distribution in a rectangular waveguide with the goffered bottom wall by the method of the connected waves is conducted by transformation of the homogeneous differential equation with non-uniform boundary conditions to the non-uniform differential equation with homogeneous boundary conditions. The electromagnetic field in the cells of the corrugation of a rectangular waveguide with a corrugated bottom wall is found through the vector potential, which depends on the radial coordinate. The function of changing the electromagnetic field along the radial coordinate is determined by solving the Bessel equation. The vector of the magnetic field strength and the amplitudes of the components of the magnetic field strengths in the cross section of a rectangular waveguide and the component of the electric field strength tangential to the cell surface are found through the vector potential. The tangential component of the electric field strength along the narrow walls of a rectangular waveguide is calculated. An equivalent magnetic surface current is introduced along the wide and narrow walls of a rectangular waveguide. For a regular rectangular waveguide with magnetic currents on its walls, solutions of equations that satisfy the orthogonality conditions, for determining the amplitudes of electromagnetic fields in the positive and negative directions along the axis of the regular rectangular waveguide, correction to the wave propagation constant of the i-th k'j type is given. The graphs of the calculated and experimental dependences of the propagation constant k'j on the ratio λ/a (λ - wavelength, m) for waves of quasi types H10, H20, and H01 in a WR-112 rectangular waveguide with cross-sectional dimensions (a x b) mm = (28,5 x 12,64) mm with a corrugated bottom wall at fixed relative dimensions of the cell depth t, the distance between the corrugations s and the width of the lower base of the trapezoid of the cross-section of the corrugation D — δ=t/a, u=s/a, and p=D/a. The dependences of the propagation constant k'j on the ratio λ/a for a quasi-type wave H10 were studied in the frequency range from 5.2 GHz to 7.1 GHz, for a quasi-type wave H20 - from 10.5 GHz to 11.8 GHz, for a quasi-type wave H01 - from 11.7 GHz up to 18.1 GHz. The dispersion characteristics of waves of the types of quasi H10, H20, and H01 a rectangular waveguide with a corrugated bottom wall with a decrease in the relative depth of the corrugation δ approach the dispersion characteristics of the types of waves of a regular rectangular waveguide and, in the case of the boundary (δ→0), coincide with them. The error of the calculated data relative to the experimental data is about 5%, which confirms the suitability of the proposed method for practical calculations even in the first approximation.The proposed technique may be appropriate for choosing the approximation that provides the required calculation accuracy in practice with a minimum amount of computation.The reliability and validity of the results obtained is ensured by the convergence of the results of the calculation according to the boundary conditions with the known results and the convergence of the formulas obtained by the units of measurement.

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Han, Congzheng, Liang Feng, Juan Huo, et al. "Characteristics of Rain-Induced Attenuation over Signal Links at Frequency Ranges of 25 and 38 GHz Observed in Beijing." Remote Sensing 13, no. 11 (2021): 2156. http://dx.doi.org/10.3390/rs13112156.

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Wireless communication has become a very important part of our lives, and it is well known that meteorological factors affect the quality of communication links, especially at higher frequencies because the physical dimensions of raindrops, hail stones, and snowflakes are on a similar wavelength to the propagating radio frequency. Millimeter-waves are an important technology for fifth-generation cellular networks which are currently being deployed all over the world. Since atmospheric effects are challenging in millimeter-wave transmissions, in this paper, we conducted line-of-sight field measurements at 25 GHz and 38 GHz. We monitored the received signal during rainfall events and compared the theoretical attenuation and the recorded rain-induced attenuation. We also derived the rain-induced attenuation (A) and rainfall rate (R) relation for stratiform and convective rain, respectively, using local rain drop size distribution (DSD) information at our measurement site collected during the period of two years. Furthermore, opportunistic sensing of atmospheric phenomena using microwave or millimeter-wave communication links in commercial cellular networks has recently attracted more attention in meteorological research worldwide. The accuracy of calculating rainfall rates from microwave links highly depends on the retrieval model and values of coefficients in the model, i.e., a and b of the A-R relation model. Here, the coefficients a and b are estimated based on local DSD measurement, and the performance of the improved A-R model is evaluated using propagated signal power based on measurement data. Compared to the (a, b) coefficients in the International Telecommunication Union Recommendation (ITU-R) P.838 document, the derived coefficients achieved an improved rainfall rate estimation.

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Cheng, Wei‐Chung, Yi‐Qi Lin, Wern‐Ho Sheen, Cheng‐Hung Hsieh, Jeen‐Hwan Tarng, and Zuo‐Min Tsai. "Measurement‐based delay, angular dispersion and propagation loss characteristics of outdoor propagation in beam domain and multi‐beam operation at 38 GHz for 5‐G communication systems." IET Microwaves, Antennas & Propagation 16, no. 5 (2022): 257–71. http://dx.doi.org/10.1049/mia2.12239.

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Alhilali, Manhal, Jafri Din, Michael Schönhuber, and Hong Yin Lam. "Estimation of Millimeter Wave Attenuation Due to Rain using 2D Video Distrometer Data in Malaysia." Indonesian Journal of Electrical Engineering and Computer Science 7, no. 1 (2017): 164. http://dx.doi.org/10.11591/ijeecs.v7.i1.pp164-169.

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<p>The increasing use of millimeter wave frequency bands requires a good understanding of the atmospheric channel. In equatorial regions, rain plays the central role in the impairment of millimeter wave propagation. Using large amounts of precise data collected by a two-dimensional video distrometer in Malaysia, the rain-specific attenuation of both vertically and horizontally polarized waves at the 38 GHz frequency was computed by applying the T-matrix technique. Good agreement is observed between these computations and fitted power law models from neighboring areas, but the ITU-R Recommendation P.838-3 significantly underestimates the rain-specific attenuation. The importance of including raindrop axial ratio in the calculation is revealed by differences among the local fitted coefficients for the vertically polarized estimations. The power law fit is provided, and the measurement is verified.</p>

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Zhang, Zhaolei, Yu Liu, Jie Huang, Jingfan Zhang, Jingquan Li, and Ruisi He. "Channel Characterization and Modeling for 6G UAV-Assisted Emergency Communications in Complicated Mountainous Scenarios." Sensors 23, no. 11 (2023): 4998. http://dx.doi.org/10.3390/s23114998.

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Regarding the new demands and challenges of sixth-generation (6G) mobile communications, wireless networks are undergoing a significant shift from traditional terrestrial networks to space-air-ground-sea-integrated networks. Unmanned aerial vehicle (UAV) communications in complicated mountainous scenarios are typical applications and have practical implications, especially in emergency communications. In this paper, the ray-tracing (RT) method was applied to reconstruct the propagation scenario and then acquire the wireless channel data. Channel measurements are also conducted in real mountainous scenarios for verification. By setting different flight positions, trajectories, and altitudes, channel data in the millimeter wave (mmWave) band was obtained. Important statistical properties, such as the power delay profile (PDP), Rician K-factor, path loss (PL), root mean square (RMS) delay spread (DS), RMS angular spreads (ASs), and channel capacity were compared and analyzed. The effects of different frequency bands on channel characteristics at 3.5 GHz, 4.9 GHz, 28 GHz, and 38 GHz bands in mountainous scenarios were considered. Furthermore, the effects of extreme weather, especially different precipitation, on the channel characteristics were analyzed. The related results can provide fundamental support for the design and performance evaluation of future 6G UAV-assisted sensor networks in complicated mountainous scenarios.

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Budalal, Asma Ali, Islam Md Rafiqul, Mohamed Hadi Habaebi, and Tharek Abd Rahman. "The effects of rain fade on millimetre wave channel in tropical climate." Bulletin of Electrical Engineering and Informatics 8, no. 2 (2019): 653–64. http://dx.doi.org/10.11591/eei.v8i2.1487.

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The main objective of this paper to determine multipath and time-varying channel behaviour of short-terrestrial millimetre-wave point-to-point radio links. In an attempt to invigorate the impact of rain attenuation on mm-wave channel parameters such as the RMS delay spread, path loss received power strength and Rician distribution with a K factor. A brief analysis of rain fading was presented based on the simultaneous measurement of one-minute rain rate and its effects on a short experimental link of 38 GHz. Rain fade average is observed as high as 16 dB for 300 m path at about 125 mm/hr rain intensity. The statistical spatial channel mode (SSCM) simulation software was utilized for an operating frequency of 38 GHz. To generate of power delay profile (PDP). For both omnidirectional and directional antenna. The RMS delay spread and path loss has been estimated using the environmental parameters of Kuala Lumpur city which illustrates the theoretical performances of 5G in Malaysia. It is observed that RMS delay spread, path loss received power strength and K factor effected dramatically by rain fade. (SSCM) simulation software has to be modified to consider rain fade dynamic characteristics to achieve ultra-reliability requirements of outdoor applications in the tropical regions. This study is important for understanding signal propagation phenomena in short distance and enabling the utilization of the millimetre wave band for an urban micro-cellular environment for 5G communication system.

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Alyosef, Ayham, Domenico Cimini, Lorenzo Luini, et al. "Improving atmospheric path attenuation estimates for radio propagation applications by microwave radiometric profiling." Atmospheric Measurement Techniques 14, no. 4 (2021): 2737–48. http://dx.doi.org/10.5194/amt-14-2737-2021.

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Abstract. Ground-based microwave radiometer (MWR) observations of downwelling brightness temperature (TB) are commonly used to estimate atmospheric attenuation at relative transparent channels for radio propagation and telecommunication purposes. The atmospheric attenuation is derived from TB by inverting the radiative transfer equation with a priori knowledge of the mean radiating temperature (TMR). TMR is usually estimated by either time-variant site climatology (e.g., monthly average computed from atmospheric thermodynamical profiles) or condition-variant estimation from surface meteorological sensors. However, information on TMR may also be extracted directly from MWR measurements at channels other than those used to estimate atmospheric attenuation. This paper proposes a novel approach to estimate TMR in clear and cloudy sky from independent MWR profiler measurements. A linear regression algorithm is trained with a simulated dataset obtained by processing 1 year of radiosonde observations of atmospheric thermodynamic profiles. The algorithm is trained to estimate TMR at K- and V–W-band frequencies (22–31 and 72–82 GHz, respectively) from independent MWR observations at the V band (54–58 GHz). The retrieval coefficients are then applied to a 1-year dataset of real V-band observations, and the estimated TMR at the K and V–W band is compared with estimates from nearly colocated and simultaneous radiosondes. The proposed method provides TMR estimates in better agreement with radiosondes than a traditional method, with 32 %–38 % improvement depending on frequency. This maps into an expected improvement in atmospheric attenuation of 10 %–20 % for K-band channels and ∼30 % for V–W-band channels.

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Perov, Dmitry V., and Anatoly B. Rinkevich. "Ferromagnetic Resonance and Antiresonance in Composite Medium with Flakes of Finemet-Like Alloy." Nanomaterials 11, no. 7 (2021): 1748. http://dx.doi.org/10.3390/nano11071748.

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Propagation of microwaves is studied in a composite material containing flakes of Fe-Si-Nb-Cu-B alloy placed into an epoxyamine matrix. The theory is worked out, which permits to calculate the coefficients of the dynamic magnetic permeability tensor and the effective magnetic permeability of the transversely magnetized composite. The measurements of magnetic field dependences of the transmission and reflection coefficients were carried out at frequencies from 12 to 38 GHz. Comparison between calculated and measured coefficients were conducted, which show that the calculation reproduces all main features of the resonance variations caused by ferromagnetic resonance and antiresonance. The dissipation of microwave power was calculated and measured. It is shown that the penetration depth of the electromagnetic field increases under antiresonance condition and decreases under resonance.

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Modupe E, Sanyaolu. "PERFORMANCE OF RAIN- INDUCED ATTENUATION PREDICTION MODELS FOR TERRESTRIAL LINK IN CAMEROON." International Journal of Engineering Applied Sciences and Technology 7, no. 1 (2022): 17–25. http://dx.doi.org/10.33564/ijeast.2022.v07i01.003.

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Weather, notably rain, has a negative impact on radio wave propagation between terrestrial and earthspace links at frequencies above 10 GHz. Therefore raininduced attenuation is a significant propagation impact that must be considered when designing satellite communication systems. Analysis of rain attenuation for earth-space links in three locations in Cameroon at V, Ku and Ka bands is investigated using four rain attenuation models: The ITU-R P.618 model, Svjatogor model, GarciaLopez model and Bryant model at 42.5° elevation angles. The major goal is to figure out which rain attenuation prediction models are best for satellite communication in this area. Five years (2013–2017) daily rainfall data obtained from the Tropical Rain Measuring MissionPrecipitation Radar (TRMM-PR) and Global Precipitation Measurement (GPM) mission's Core Observatory were used for this study. The results showed that the ITUR P.618, Garcia-Lopez, and Svjatogor models performed best in this region. Attenuation ranged from 15 dB to 16 at 42.5° elevation angle for time exceedance of 0.01% at Kuband in all the study locations. For the Ka-band, attenuation varied between 32 dB and 38 dB. Signal availability at Ku-band is possible based on predicted rain attenuation values for 0.01 %-time exceedance. At Ka and V-band, the predicted rain attenuation values for 0.01%- time exceedance have shown that availability of signal is impossible, which infers losses of the signal during such rainfall events across the selected locations in Cameroon

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Moscadelli, L., A. Sanna, C. Goddi, V. Krishnan, F. Massi, and F. Bacciotti. "Protostellar Outflows at the EarliesT Stages (POETS)." Astronomy & Astrophysics 635 (March 2020): A118. http://dx.doi.org/10.1051/0004-6361/202037472.

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Context. 22 GHz water masers are the most intense and widespread masers in star-forming regions. They are commonly associated with protostellar winds and jets emerging from low- and high-mass young stellar objects (YSO). Aims. We wish to perform for the first time a statistical study of the location and motion of individual water maser cloudlets, characterized by typical sizes that are within a few au, with respect to the weak radio thermal emission from YSOs. Methods. For this purpose, we have been carrying out the Protostellar Outflows at the EarliesT Stages survey of a sample (38) of high-mass YSOs. The 22 GHz water maser positions and three-dimensional (3D) velocities were determined through multi-epoch Very Long Baseline Array observations with accuracies of a few milliarcsec (mas) and a few km s−1, respectively. The position of the ionized core of the protostellar wind, marking the YSO, was determined through sensitive radio continuum, multi-frequency Jansky Very Large Array observations with a typical error of ≈20 mas. Results. The statistic of the separation of the water masers from the radio continuum shows that 84% of the masers are found within 1000 au from the YSO and 45% of them are within 200 au. Therefore, we can conclude that the 22 GHz water masers are a reliable proxy for locating the position of the YSO. The distribution of maser luminosity is strongly peaked towards low values, indicating that about half of the maser population is still undetected with the current Very Long Baseline Interferometry detection thresholds of 50–100 mJy beam−1. Next-generation, sensitive (at the nJy level) radio interferometers will have the capability to exploit these weak masers for an improved sampling of the velocity and magnetic fields around the YSOs. The average direction of the water maser proper motions provides a statistically-significant estimate for the orientation of the jet emitted by the YSO: 55% of the maser proper motions are directed on the sky within an angle of 30° from the jet axis. Finally, we show that our measurements of 3D maser velocities statistically support models in which water maser emission arises from planar shocks with propagation direction close to the plane of the sky.

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Chukhlanov, Vladimir Yu, Natalia N. Smirnova, and Kirill V. Smirnov. "Dielectric characteristics of epoxy resin modified with tetraethoxysilane in the millimeter range." Butlerov Communications 62, no. 4 (2020): 77–80. http://dx.doi.org/10.37952/roi-jbc-01/20-62-4-77.

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In this work, the influence of alkoxysilanes introduced into the epoxy resin was studied. That was done in order to study the possibility of using the obtained binders in composite materials with increased radio transparency in the millimetre microwave radio band. Determination of the modified epoxy resin dielectric characteristics in the millimetre microwave radio transparency was carried out by the waveguide method. The measuring complex consisted of a precision measuring line P1-31, a tunable generator on a Gann diode (30-38 GHz), a ferrite gate, and a section of a standard-section waveguide. Based on measurements of the minimum position displacement of the standing wave coefficient by known propagation constants, the free-space wavelength λ0 for a given operating frequency, and the critical wavelength in the waveguide λcr, the loss angle tangent tg(δ) and the permittivity ε were calculated. Calculations of the permittivity ε, the angle of the dielectric loss tg(δ) and the radio transparency loss-ΔР were performed in the MathСad. Moisture absorption of samples was determined by holding them in a desiccator with a humidity of 98 %. The samples were kept in a tightly closed desiccator for 24 hours at a temperature of 25 oC. In addition, the relative moisture absorption was determined using the increase in mass. It was found that the introduction of tetraethoxysilane in the composition in an amount of 1.5-3.5% leads to a decrease in the tangent of the dielectric loss angle. The optimum is observed in the range of the modifier concentration of 2.5-3.5%. This fact confirms that at these concentrations there is a complete interaction of TEOS alkoxygroups with epoxy resin epoxygroups.

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Hamid, Nagham. "Evaluation of Power Receiving Signal of 5G Small Cells for Outdoor/Indoor Environment at Millimeterwave Bands." Applied Computational Electromagnetics Society 36, no. 2 (2021): 184–89. http://dx.doi.org/10.47037/2020.aces.j.360210.

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This paper presents a simulation study of the outdoor and indoor propagation losses utilizing 5G small cells at suggested millimeter-wave frequencies of 26 GHz, 28 GHz, and 38 GHz. The environment of this study is conducted with penetration loss of new and old building characteristics. The simulation is performed with help of 3D ray tracing model NVIDIA OptiX engine and MATLAB. The targeted frequencies are 26 GHz, 28 GHz, and 38 GHz that specified by International Telecommunication Union ITU-R organization. The simulation routes are investigated in term of signal strength at multiple receiving points. The strength angular spectrum are represented for fixed points and the power receiving delay is presented by their attributes. The simulated responses showed an efficient and sufficient outdoor and indoor service might be provisioned at 26 GHz and 28 GHz. The received signals at 28 GHz and 38 GHz are found around 4.5 dB and 11 dB with comparison with signal received level at 26 GHz. However, at 38 GHz the indoor signal strength and power receiving delays demonstrate a weak signal reception which offers a poor solution to indoor user by outside fixed base station.

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Bhutani, Akanksha, Sören Marahrens, Marius Kretschmann, et al. "Applications of radar measurement technology using 24 GHz, 61 GHz, 80 GHz and 122 GHz FMCW radar sensors." tm - Technisches Messen 89, no. 2 (2021): 107–21. http://dx.doi.org/10.1515/teme-2021-0034.

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Abstract This paper presents a review of radar applications in high-accuracy distance measurement of a target. The radars included in this review are frequency modulated continuous wave (FMCW) radar sensors operating in four different millimeter-wave frequency bands, namely 24 GHz, 61 GHz, 80 GHz and 122 GHz. The radar sensors are used to measure the distance of standard and complex targets in a short range of a few meters, thus indicating that the choice of target and the medium used for radar signal propagation also play a key role in determining the distance measurement accuracy of an FMCW radar. The standard target is a trihedral corner reflector in a laboratory-based free space measurement setup and the complex targets include a piston in an oil-filled hydraulic cylinder and a planar positioning stage used in micromachining. In each of these measurement scenarios, a distance measurement accuracy in micrometer range is achieved due to the use of a sophisticated signal processing algorithm that is based on a combined frequency and phase estimation method. The paper is concluded with a technical comparison of the accuracy achieved by the FMCW radars reviewed in this article with other related works.

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Čoko, Duje, Dinko Begušić, and Zoran Blažević. "UWB Radio Propagation Measurements in a Desktop Environment." Journal of Communications Software and Systems 6, no. 2 (2010): 74. http://dx.doi.org/10.24138/jcomss.v6i2.192.

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The ultra-wideband wireless personal area networks are expected to be most commonly employed in desktop environments. This paper presents a measurement campaignconducted on a typical office desk. A pair of omnidirectionalUWB antennas and a vector network analyzer were used tomeasure the impulse responses over a frequency rang spanning from 6 GHz to 8.5 GHz, in accordance with the UWB regulations in Europe. The coherence bandwidth and the rms delay spread are calculated from the measurement results. A significant correlation between these wideband parameters is found, but only at higher correlation thresholds.

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Lai, Fei-Peng, Lu-Wu Chang, and Yen-Sheng Chen. "Miniature Dual-Band Substrate Integrated Waveguide Slotted Antenna Array for Millimeter-Wave 5G Applications." International Journal of Antennas and Propagation 2020 (October 12, 2020): 1–10. http://dx.doi.org/10.1155/2020/6478272.

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A compact substrate integrated waveguide (SIW) antenna array that operates at 28 GHz and 38 GHz is proposed for fifth generation (5G) applications. The proposed array consists of four SIW cavities fabricated on one single layer of substrate. Each cavity implements a rhombic slot and a triangular-split-ring slot, resonating on TE101 and TE102 modes at 28 GHz and 38 GHz, respectively. In comparison with dual-band SIW antennas in the literature, the proposed configuration depicts a miniature footprint (28.7 × 30.8 mm2) without stacking substrates. To excite the four cavities with equal power, a broadband power divider that supports the propagation of TE10 mode is designed. Accordingly, the impedance bandwidths are 26.6–28.3 GHz and 36.8–38.9 GHz. The measured realized peak gain over the lower and higher bands is 9.3–10.9 dBi and 8.7–12.1 dBi, respectively. The measured half-power beam widths (HPBWs) at 28 GHz and 38 GHz are 20.7° and 15.0°, respectively. Considering these characteristics, including dual bands, high gain, narrow beam widths, miniaturization, and single layer, the proposed antenna array is a suitable candidate for millimeter-wave 5G communication systems with the flexibility in switching operating frequency bands against channel quality variations.

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Kim, Minseok, Anirban Ghosh, Riku Takahashi, and Kosuke Shibata. "Indoor Channel Measurement at 300 GHz and Comparison of Signal Propagation With 60 GHz." IEEE Access 11 (2023): 124040–54. http://dx.doi.org/10.1109/access.2023.3330653.

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Kanazawa, Ami, and Hiroyo Ogawa. "Propagation measurement of 70-GHz band in a moving train." Electronics and Communications in Japan (Part III: Fundamental Electronic Science) 89, no. 8 (2006): 21–29. http://dx.doi.org/10.1002/ecjc.20183.

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Nor Raihan Zulkefly, Omar Abd. Aziz, Ibraheem Shayea, and Ahmed Al-Saman. "Path Loss Models for 5G Communications System in Corridors Environment." Journal of Advanced Research in Applied Sciences and Engineering Technology 46, no. 1 (2024): 86–96. http://dx.doi.org/10.37934/araset.46.1.8696.

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This paper presents the propagation path loss channel models, developed from real-field measurement in Universiti Teknologi Malaysia (UTM) Kuala Lumpur, Malaysia. The purpose of the study is to characterize the channel at 28 GHz for 5G communications system in line-of-sight corridors environment. Measurement campaigns were conducted to measure the wireless signal of received signal strength at three different construction of straight corridors, narrow, wide, and open corridors. The large-scale path loss models are developed using the closed-in reference distance and floating–intercept modeling approaches. Besides contributing path loss models at 28 GHz for different corridors dimension, the result found in this work discovered the breakpoint distance of radio propagation is seen varies differently at those corridors.

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Ahmed, Bazil Taha. "Propagation Loss Measurement of Wireless Body Area Network at 2.4 GHz and 3.35 GHz Bands." Wireless Personal Communications 112, no. 2 (2020): 685–716. http://dx.doi.org/10.1007/s11277-020-07068-w.

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Macedo, Alex, Thiago Costa, Edemir de Matos, et al. "Channel Analysis for 3.5 GHz Frequency in Airport." Journal of Communication and Information Systems 38, no. 1 (2023): 115–20. http://dx.doi.org/10.14209/jcis.2023.13.

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This letter presents an analysis of the radio propagation channel based on measurements at the 3.5 GHz frequency. The measurement campaigns were carried out inside the Valde-Cans airport using line-of-sight (LOS) transmissions. First, the channel small-scale dispersion parameters were extracted through channel probing and the results are similar to those obtained by ITU-R P.1238 for the bands below 15 GHz considering commercial indoor environments as well as for those using the 3.5 GHz band in outdoor environments utilizing WiMax OFDM-256 signals. Then, the floating-intercept (FI) and close-in (CI) models are applied and analyzed to evaluate the received signal behavior for co-polarized and cross polarized antennas. The results show that the CI path loss exponent values are close to the free space propagation loss model, while the FI model provides a lower root mean square error (RMSE) to the measured data. The results show that the FI and CI models are suitable for large-scale indoor propagation loss modeling for 5G networks with a frequency of 3.5 GHz.

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Han, Congzheng, Yongheng Bi, Shu Duan, and Gaopeng Lu. "Rain Rate Retrieval Test From 25-GHz, 28-GHz, and 38-GHz Millimeter-Wave Link Measurement in Beijing." IEEE Journal of Selected Topics in Applied Earth Observations and Remote Sensing 12, no. 8 (2019): 2835–47. http://dx.doi.org/10.1109/jstars.2019.2918507.

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Wysocki, Tadeusz A., and Hans-Jurgen Zepernick. "Characterization of the indoor radio propagation channel at 2.4 GHz." Journal of Telecommunications and Information Technology, no. 3-4 (December 30, 2000): 84–90. http://dx.doi.org/10.26636/jtit.2000.3-4.23.

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The unlicensed industrial, scientific, and medical (ISM) band at 2.4 GHz has gained increased attention recently due to the high data rate communication systems developed to operate in this band. The paper presents measurement results of fading characteristics, multipath parameters and background interference for these frequencies. Some statistical analysis of the measured data is presented. The paper provides information that may be useful in design and deployment of communication systems operating in the 2.4 GHz ISM band, like those compliant with IEEE 802.11 standard and Bluetooth open wireless standard

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Ito, Satoshi, and Takahiro Hayashi. "Measurement and Evaluation of 28 GHz Propagation Characteristics in Specific Environments." IEEE Access 10 (2022): 26242–56. http://dx.doi.org/10.1109/access.2022.3157063.

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Taha-Ahmed, Bazil, Jose Luis Masa-Campos, and David Fernandez Campillo. "PROPAGATION LOSS MEASUREMENT DUE TO MISCELLANEOUS PHENOMENON AT 5.6 GHZ BAND." Progress In Electromagnetics Research C 32 (2012): 207–20. http://dx.doi.org/10.2528/pierc12072304.

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Qian, Jingyuan, Yating Wu, Asad Saleem, and Guoxin Zheng. "Path Loss Model for 3.5 GHz and 5.6 GHz Bands in Cascaded Tunnel Environments." Sensors 22, no. 12 (2022): 4524. http://dx.doi.org/10.3390/s22124524.

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An important and typical scenario of radio propagation in a railway or subway tunnel environment is the cascaded straight and curved tunnel. In this paper, we propose a joint path loss model for cascaded tunnels at 3.5 GHz and 5.6 GHz frequency bands. By combining the waveguide mode theory and the method of shooting and bouncing ray (SBR), it is found that the curvature of tunnels introduces an extra loss in the far-field region, which can be modeled as a linear function of the propagation distance of the signal in the curved tunnel. The channel of the cascaded straight and curved tunnel is thus characterized using the extra loss coefficient (ELC). Based on the ray-tracing (RT) method, an empirical formula between ELC and the radius of the curvature is provided for 3.5 GHz and 5.6 GHz, respectively. Finally, the accuracy of the proposed model is verified by measurement and simulation results. It is shown that the proposed model can predict path loss in cascaded tunnels with desirable accuracy and low complexity.

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Al-Samman, Ahmed Mohammed, Tharek Abd. Rahman, Tawfik Al-Hadhrami, et al. "Comparative Study of Indoor Propagation Model Below and Above 6 GHz for 5G Wireless Networks." Electronics 8, no. 1 (2019): 44. http://dx.doi.org/10.3390/electronics8010044.

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It has been widely speculated that the performance of the next generation based wireless network should meet a transmission speed on the order of 1000 times more than the current cellular communication systems. The frequency bands above 6 GHz have received significant attention lately as a prospective band for next generation 5G systems. The propagation characteristics for 5G networks need to be fully understood for the 5G system design. This paper presents the channel propagation characteristics for a 5G system in line of sight (LOS) and non-LOS (NLOS) scenarios. The diffraction loss (DL) and frequency drop (FD) are investigated based on collected measurement data. Indoor measurement results obtained using a high-resolution channel sounder equipped with directional horn antennas at 3.5 GHz and 28 GHz as a comparative study of the two bands below and above 6 GHz. The parameters for path loss using different path loss models of single and multi-frequencies have been estimated. The excess delay, root mean square (RMS) delay spread and the power delay profile of received paths are analyzed. The results of the path loss models show that the path loss exponent (PLE) in this indoor environment is less than the free space path loss exponent for LOS scenario at both frequencies. Moreover, the PLE is not frequency dependent. The 3GPP path loss models for single and multi-frequency in LOS scenarios have good performance in terms of PLE that is as reliable as the physically-based models. Based on the proposed models, the diffraction loss at 28 GHz is approximately twice the diffraction loss at 3.5 GHz. The findings of the power delay profile and RMS delay spread indicate that these parameters are comparable for frequency bands below and above 6 GHz.

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Rubio, Lorenzo, Rafael P. Torres, Vicent M. Rodrigo Peñarrocha, et al. "Contribution to the Channel Path Loss and Time-Dispersion Characterization in an Office Environment at 26 GHz." Electronics 8, no. 11 (2019): 1261. http://dx.doi.org/10.3390/electronics8111261.

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In this paper, path loss and time-dispersion results of the propagation channel in a typical office environment are reported. The results were derived from a channel measurement campaign carried out at 26 GHz in line-of-sight (LOS) and obstructed-LOS (OLOS) conditions. The parameters of both the floating-intercept (FI) and close-in (CI) free space reference distance path loss models were derived using the minimum-mean-squared-error (MMSE). The time-dispersion characteristics of the propagation channel were analyzed through the root-mean-squared (rms) delay-spread and the coherence bandwidth. The results reported here provide better knowledge of the propagation channel features and can be also used to design and evaluate the performance of the next fifth-generation (5G) networks in indoor office environments at the potential 26 GHz frequency band.

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Firdausi, Ahmad, Lusi Damayanti, Galang Persada Nur Hakim, Umaisaroh Umaisaroh, and Mudrik Alaydrus. "Design of A Dual-Band Microstrip Antenna for 5G Communication." Journal of Integrated and Advanced Engineering (JIAE) 1, no. 1 (2021): 65–72. http://dx.doi.org/10.51662/jiae.v1i1.15.

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The necessity for mobile communication devices is increased rapidly. Users expect to get very fast information access and data access without delay. The fifth-generation (5G) development in wireless mobile telecommunication technology promises capacity enhancement, ease connectivity, high efficiency, and high data rate transmission. The appropriate device should support this improvement of the technology. The antenna is one of the main devices to support the high data rate transmission. This paper proposed designing a dual-band rectangular patch antenna in 29 GHz and 38 GHz that supports 5G technology. This microstrip antenna is composed of 4 patch array elements to obtain higher gain. The material used for this microstrip antenna is RT Duroid 5880 with a dielectric constant of 2.2 and a thickness of 1.575 mm. Both measurement and simulation are confirmed that the 2×2 array microstrip antenna in 29 GHz and 38 GHz frequency have a return loss value of -12.5 dB and -16 dB, respectively. The bandwidth for both frequencies has a value of 4.5 GHz and 3.75 GHz.

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Кузьмин, Л. В., та Е. В. Ефремова. "Эксперимент по определению времени прохождения сверхширокополосных хаотических радиоимпульсов через многолучевой канал". Письма в журнал технической физики 46, № 16 (2020): 23. http://dx.doi.org/10.21883/pjtf.2020.16.49849.18352.

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Here we describe experimental measurement results on the time of propagation of 3–5 GHz ultra-wideband chaotic radio pulses through multipath wireless channel. The accuracy of measuring the propagation time of ultra-wideband chaotic radio pulses by their envelope is evaluated. The achieved accuracy is sufficient for solving the problem of measuring the distance between objects and their localization in space in the industrial and office environments.

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Valtr, Pavel, Jan Zeleny, Pavel Pechac, and Martin Grabner. "Clutter Loss Modelling for Low Elevation Link Scenarios." International Journal of Antennas and Propagation 2016 (2016): 1–4. http://dx.doi.org/10.1155/2016/1478471.

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An analysis of the accuracy of several deterministic and semideterministic propagation models related to calculating clutter loss for low elevation links is presented. Predictions are compared with measurements carried out at 2 GHz over three locations. By comparing prediction and measurement techniques, improved predictive capabilities of deterministic models are demonstrated and quantified in cases where a description of the propagation environment exists and an air-to-ground scenario is considered.

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Batalha, Iury S., Andréia V. R. Lopes, Jasmine P. L. Araújo, et al. "Large-Scale Channel Modeling and Measurements for 10 GHz in Indoor Environments." International Journal of Antennas and Propagation 2019 (January 23, 2019): 1–10. http://dx.doi.org/10.1155/2019/9454271.

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With the advent of 5G mobile communication and researches into the propagation of large-scale channel modeling for frequencies above 6 GHz, measurement investigation was performed at 10 GHz with horn-type directional antennas in a corridor and a computer room within the Electrical and Computer Engineering Laboratories’ first floor, at Federal University of Pará (UFPA), Brazil. This paper presents data obtained through experimental work, channel modeling with co-polarization V-V and H-H and cross-polarization V-H in line-of-sight (LOS) or non-line-of-sight (NLOS) conditions. The large-scale close-in reference is sustained by a comprehensive analysis, considering propagation mechanisms such as reflection and diffraction. Results demonstrate that the established model had inferior standard deviation in relation to measured data, proving itself more significant to propagation in indoor environments.

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Al-Bawri, Samir Salem, Md Shabiul Islam, Hin Yong Wong, et al. "Metamaterial Cell-Based Superstrate towards Bandwidth and Gain Enhancement of Quad-Band CPW-Fed Antenna for Wireless Applications." Sensors 20, no. 2 (2020): 457. http://dx.doi.org/10.3390/s20020457.

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A multiband coplanar waveguide (CPW)-fed antenna loaded with metamaterial unit cell for GSM900, WLAN, LTE-A, and 5G Wi-Fi applications is presented in this paper. The proposed metamaterial structure is a combination of various symmetric split-ring resonators (SSRR) and its characteristics were investigated for two major axes directions at (x and y-axis) wave propagation through the material. For x-axis wave propagation, it indicates a wide range of negative refractive index in the frequency span of 2–8.5 GHz. For y-axis wave propagation, it shows more than 2 GHz bandwidth of near-zero refractive index (NZRI) property. Two categories of the proposed metamaterial plane were applied to enhance the bandwidth and gain. The measured reflection coefficient (S11) demonstrated significant bandwidths increase at the upper bands by 4.92–6.49 GHz and 3.251–4.324 GHz, considered as a rise of 71.4% and 168%, respectively, against the proposed antenna without using metamaterial. Besides being high bandwidth achieving, the proposed antenna radiates bi-directionally with 95% as the maximum radiation efficiency. Moreover, the maximum measured gain reaches 6.74 dBi by a 92.57% improvement compared with the antenna without using metamaterial. The simulation and measurement results of the proposed antenna show good agreement.

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Journal articles on the topic '38 GHz propagation measurement'

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