Dissertations / Theses on the topic 'PIFA antenna design'

This thesis focuses on mobile phones antenna design with brief description about the historical development, basic parameters and the types of antennas which are used in mobile phones. Mobile phones antenna design section consists of two proposed PIFA antennas. The first design concerns a single band antenna with resonant frequency at GPS frequency (1.575GHz). The first model is designed with main consideration that is to have the lower possible PIFA single band dimensions with reasonable return loss (S11) and the efficiencies. Second design concerns in a wideband PIFA antenna which cover the range from 1800MHz to 2600MHz. This range covers certain important bands: GSM (1800MHz & 1900MHz), UMTS (2100MHz), Bluetooth & Wi-Fi (2.4GHz) and LTE system (2.3GHz, 2.5GHz, and 2.6GHz). The wideband PIFA design is achieved by using slotted ground plane technique. The simulations for both models are performed in COMSOL Multiphysics.  The last two parts of the thesis present the problems of mobile phones antenna. Starting with Specific absorption rate (SAR) problem, efficiency of Mobile phones antenna, and hand-held environment.

The beginning of the 21 st century is characterised, among others, by the evolution in telecommunications. The rapid growth of mobile communications and the variety of applications proposed for the third generation (3G) systems require long operation time, low weight and cost for terminals, as well as improved link quality. For this reason a good efficiency and low profile antennas with low absorption losses by the user are desirable. The Planar Inverted-F Antenna (PIFA) is shown to result into low SAR values and high efficiency when operating in the proximity of the user. Despite these advantages, PIFA is also characterised by narrow bandwidth that limits its practical use. The first part of this work is dedicated to the measurements and evaluation of the radiation characteristics of the PIFA and other wire antennas both in the near and far fields. In addition, novel methods of PIFA tuning are presented. These include the repositioning of the shorting pin and modification of its capacitance. By using these techniques, the effective bandwidth of the PIFA can be increased to satisfy the GSM900 and DCS 1800 system bandwidth requirements. Dual-band and electronically tuned PIFA prototypes are also included. The effects of the handset size on the mass averaged Specific Absorption Rate (SAR), and antenna efficiency are investigated. The appropriate choice of handset can result in up to 30%-reduced peak SAR. The computed SAR values from PIFA are compared with those resulting from the use of a handset equipped with quarter wavelength monopole antenna. A new measure referred to as the 3dB SAR volume is proposed. This measure provides better understanding of the absorbed power distribution in the operator's head. Results obtained in the course of study show that low profile handset antennas, such as the PIFA, present in addition to dual resonance and low reflection losses, reduced SAR values, high efficiency and low 3dB SAR volume. Finally, SAR and 3dB SAR volume values from simulations on 5- and 10- years old child head models are compared with their equivalents for adult models from which appropriate conclusions are drawn.

The rapidly growing demand for UWB as high data rates wireless communications technology, since the Federal Communications Commission (FCC) allocated the bandwidth of UWB from 3.1GHz to 10.6 GHz. Antenna also plays an essential role in UWB system. However, there are some difficulties in designing UWB antenna as compared to narrowband antenna. The primary requirement of UWB antennas is be able to operate over frequencies released by the FCC. Moreover, the satisfaction of radiation properties and good time domain performance over the entire frequency range are also necessary. In this thesis, designing and analysing printed crescent shape monopole antenna, Planar Inverted F-L Antenna (PIFLA) and Planar Inverted FF Antenna (PIFFA) are focused. A Planar Inverted FF Antenna (PIFFA) can be created to reduce the potential for interference between a UWB system and other communications protocols by using spiral slot. The antennas exhibits broadside directional pattern. The performances such as return loss, radiation pattern and current distribution of the UWB antennas are extensively investigated and carried out. All the results have been demonstrated using simulation and experimentally whereby all results satisfy the performance under - 10dB point in the bandwidth of UWB. In addition the miniaturization of MIMO/diversity Planar Inverted-F antenna (PIFA) which is suitable for pattern diversity in UWB applications is presented. This antenna assembly is formed by two identical PIFAs, a T-shaped decoupling structure which connects the two PIFAs and a finite ground plane with a total compact envelope dimension of 50 ¿ 90 ¿ 7.5mm3. The radiation performance of the proposed MIMO antenna was quite encouraging and provided an acceptable agreement between the computed and measured envelope correlation coefficient and channel capacity loss.<br>General Secretariat of Education and Scientific Research Libya

The rapidly growing demand for UWB as high data rates wireless communications technology, since the Federal Communications Commission (FCC) allocated the bandwidth of UWB from 3.1GHz to 10.6 GHz. Antenna also plays an essential role in UWB system. However, there are some difficulties in designing UWB antenna as compared to narrowband antenna. The primary requirement of UWB antennas is be able to operate over frequencies released by the FCC. Moreover, the satisfaction of radiation properties and good time domain performance over the entire frequency range are also necessary. In this thesis, designing and analysing printed crescent shape monopole antenna, Planar Inverted F-L Antenna (PIFLA) and Planar Inverted FF Antenna (PIFFA) are focused. A Planar Inverted FF Antenna (PIFFA) can be created to reduce the potential for interference between a UWB system and other communications protocols by using spiral slot. The antennas exhibits broadside directional pattern. The performances such as return loss, radiation pattern and current distribution of the UWB antennas are extensively investigated and carried out. All the results have been demonstrated using simulation and experimentally whereby all results satisfy the performance under - 10dB point in the bandwidth of UWB. In addition the miniaturization of MIMO/diversity Planar Inverted-F antenna (PIFA) which is suitable for pattern diversity in UWB applications is presented. This antenna assembly is formed by two identical PIFAs, a T-shaped decoupling structure which connects the two PIFAs and a finite ground plane with a total compact envelope dimension of 50 x 90 x 7.5mm³. The radiation performance of the proposed MIMO antenna was quite encouraging and provided an acceptable agreement between the computed and measured envelope correlation coefficient and channel capacity loss.

This thesis investigates the radiation characteristics of a semi-populated cellular mobile handset that uses two Printed Inverted-F Antennas (PIFAs). The investigation is carried out at three different frequencies; the LTE Band 13 (746-786 MHz), GSM-900 (890-960 MHz) and GSM-1800 (1710-1880 MHz). The mobile handset is populated with the components that affect the antenna properties the most, a battery and an LCD screen, to make the investigated model more realistic. A methodology is first presented to design the PIFAs in the presence of other components on the board. Using the outlined method, antennas for three semi-populated mobile handsets are designed to satisfy specific operational performance targets. The two PIFAs fabricated for the GSM-1800 handset have a maximum gain of 2.98 dB and 3.18 dB, reflection coefficients of below -9 dB and a maximum mutual coupling of -7.9 dB. The two fabricated PIFAs of the GSM-900 handset exhibit a maximum gain of -0.02 dB and -3 dB, reflection coefficients of below -10.5 dB and a maximum mutual coupling of -6 dB. The measured gain values for the two PIFAs of LTE-Band 13 handset prototype are 0.19 dB and -11 dB, while both achieving reflection coefficients of below -4.5 dB and a maximum mutual coupling of -11 dB. The three designs all indicate that the presence of the components on the handset degrade radiation performance. The three handsets nevertheless are well designed to meet all the performance targets except for the mutual coupling. Fullwave pointing vector simulations are conducted to investigate the coupling between the PIFAs showing that the power transfer between the GSM-1800 and GSM-900 PIFAs mostly takes place through radiation. The power coupled between the LTE-Band 13 handset antennas on the other hand is majorly through the handset's structure and substrate-bound modes.A survey of different mutual coupling reduction techniques is presented. A method that targets coupling through space-waves, i.e., the use of a parasitic radiator, is applied in this work to the GSM-1800 and GSM-900 handsets. The parasitic radiator succeeds in bringing the maximum coupling between the GSM-1800 handset antennas to below -18 dB and below -17.5 dB for the GSM-900 handset antennas. The mutual coupling between the LTE-Band 13 handset antennas is reduced by using an Electromagnetic Band-Gap structure, which successfully decreases it to below -12.2 dB.<br>Cette thèse analyse les caractéristiques des radiations d'un téléphone mobile cellulaire semi-peuplé utilisant deux antennes imprimées en F-inversé (PIFAs). L'enquête est réalisée à trois fréquences différentes; la bande LTE 13 (746-786 MHz), GSM-900 (890-960 MHz) et GSM-1800 (1710-1880 MHz). Le téléphone mobile est constitué d'une batterie et d'un écran LCD dont le but est de rendre le modèle étudié plus réaliste. Le modèle utilisé vise d'abord à représenter la conception des PIFAs et ceci avec d'autres composants. Par référence a la méthode de conception qui a été décrite, les antennes de trois semi-peuplées téléphones mobiles sont conçus pour satisfaire des objectifs spécifiques de performance opérationnelle. Les deux PIFAs fabriques pour les mobiles GSM-1800 ont un gain maximal de 2.98 dB and 3.18 dB, coefficients de réflexion inférieur à -9 dB et un couplage maximal mutuel des -7.9 dB. De plus, les deux PIFAs fabriques pour les mobiles GSM-900 ont un gain maximal de -0.02 dB and -3 dB, coefficients de réflexion ci-dessous -10.5 dB et un couplage maximal mutuel de -6 dB. Enfin, les deux PIFAs fabriques pour les mobiles LTE-Band 13 atteignent un gain maximal de 0.19 dB and -11 dB, un coefficient de réflexion ci-dessous -4.5 dB et un couplage maximal mutuel de -11 dB. Les trois modèles indiquent que la présence d'autres composants provoquent la dégradation des performances des radiations. Néanmoins, les trois mobiles répondent à toutes les caractéristiques de rendement sauf celui pour le couplage mutuel. Des simulation utilisant des vecteurs pleine-onde pointant sont effectuées pour investiguer le couplage entre les PIFAs. Les simulations indiquent que le tranfert de la puissance couplée entre les antennes pour les mobiles GSM-1800 et GSM-900 se déroule en dehors du mobile. Alors que la puissance couplée entre les antennes de téléphones LTE-bande 13 se fait à travers la structure et le substrat-lié du mobile. Une récapitulation des différentes techniques de réduction des couplages mutuels a été présentée. Une méthode visant les ondes spatiales i.e., utilisation d'un radiateur parasite, est appliquée aux mobiles GSM 1800 et GSM--900. Le radiateur parasite parvient à rendre le couplage maximal, pour les antennes GSM-1800, au-dessous de -18 dB et pour les antennes GSM-900 au-dessous de -17,5 dB.Le couplage mutuel de la LT-bande 13 est réduite en utilisant une structure de bande-interdite électromagnétique, qui apporte avec succès le couplage maximal mutuel pour les antennes à moins de -12,2 dB.En conclusion, la structure PIFA est une option viable pour une utilisation d'un téléphone mobile pour les bandes de fréquences d'une enquête, et ceci en appliquant les techniques de réduction mutuelles de couplage appropriées.

yes<br>A frequency tunable planar inverted F antenna (PIFA) is presented for use in the following bands: DCS, PCS, and UMTS. Initially, the tuning was achieved by placing a lumped capacitor, with values in the range of 1.5 to 4 pF, along the slot of the radiator. The final tuning circuit uses a varactor diode, and discrete lumped elements are fully integrated with the antenna. The antenna prototype is tunable over from 1850 MHz to 2200 MHz, with an associated volume of 21×13.5×5 mm3, making it suitable for potential integration in a commercial handset or mobile user terminal.

碩士<br>國立臺灣海洋大學<br>電機工程學系<br>102<br>The purpose of this thesis is to propose an open slot antenna and PIFA for WLAN applications. Both structure are simple and easy to make. it conformed to the requests of many consumer products and communication facilities that concerned with easy manufacture ,light weight, low cost and small size. The open slot antenna is use microstrip line to design, the antenna size is (30#westeur024#35#westeur024#0.8mm^3)，substrate thickness is 0.8mm of double-sided FR4。Front of the antenna has a rectangular metal(7#westeur024#6mm^2)，and connected to the input impedance of 50 ohm microstrip line. The back of the antenna has L-shaped and U-shaped slot，them resonate high and low frequency respectively. First use the L-shaped slot to obtained low frequency, then in the less sensitive of low frequencies and a built-in inverted U- slot to obtained the high frequency, Final change the size and shape of the slot to complete the resonant frequencies, Without increasing the antenna size to operating band of WLAN applications 2.4/5.2/5.8GHz. A typical PIFA include a rectangular metal sheet, ground plane and short circuit plate connect edge of the rectangular flat metal sheet shorter side. The proposed PIFA is use coaxial feed mechanism to design. The inner conductor of the coaxial line is connected to the radiator plane over the substrate, and through the dielectric substrate, and the outer conductor of the coaxial line connected to ground plane, and use short circuiting contactor instead of short circuit plate. By changing the size and shape of the radiator plane，or changing position of feed and short circuiting contactor to reach frequency at 2.4GHz and 5 ~ 6GHz dual-band planar inverted-F antenna's. Finally, simulate Return loss is similar to measure of the PIFA and open slot antenna. Although it is shift of frequency but is not significantly affected, the bandwidth still includes frequency of WLAN. In conclusion, the simulate and measure are not exactly the same, but the trend is close to measure of the characteristic.

碩士<br>國立臺北科技大學<br>電子工程系<br>107<br>With the rapid development of wireless communication, the demand for mobile communication devices based on multi-band operation is increasing, and the development of multi-band antennas is promoted. Planar inverted-F antenna (PIFA) has excellent performances such as small size, light weight, high efficiency and low cost, which is widely used in portable devices like mobile phones; in addition, PIFAs are also commonly applied in RFID, MIMO and wireless communication system. However, most of conventional PIFA antennas can only be operated in a single frequency band. This is the main disadvantage of the antenna, which is also the purpose of this research. In this thesis, the high-frequency structure simulator（HFSS） is used to simulate the PIFA antenna that can be worked in multi-band. Moreover, the current distribution can be observed and analyzed. The multi-band PIFA antenna is designed by the use of parasitic and slot elements, which are pattern measured in anechoic chamber and its return loss is measured by using the network analyzer. The antenna consists of main patch with parasitic element and ground plane. The volume is 40 x 31 x 0.8 〖mm〗^3 and 60 x 40 x 1.6 〖mm〗^3, respectively. The operating frequency is optimized from a single band to multi-band, which can improve the practical disadvantage of the conventional PIFA antenna effectively.

碩士<br>國立交通大學<br>電信工程系<br>91<br>Two compact antennas suitable for wireless LAN are described in this thesis. Both of them are integrated with other component simply, also can batch fabrication. A chip planar inverted F antenna structure is discussed. The chip PIFA built in FR4 substrate. The dimension of antenna is limited. Utilized simulation software, named Ansoft HFSS, the effects of bandwidth and impedance because different feed-point and different shorten-cylinder position are described. The chip PIFA has the advantage of effortless integrated with other device and mass of fabrication. Analysis of microelectromechanical systems (MEMS) technology, the meander monopole is presented. Simulations about various parameters are tested. A planar MEMS meander monopole antenna and a 3D meander monopole antenna, can integrate with CMOS process and batch fabrication are fabricated.

碩士<br>大葉大學<br>電信工程學系碩士班<br>95<br>ABSTRACT The purpose of studies in this thesis aims at designing embedded planar Inverted-F Antenna that can be applied to mobile phones. The antenna is to make use of existing aluminum foil and substrate FR4 with a commercial low price to design a kind of PIFA. The advantage of this antenna includes low cost, small size, light, easy for manufacture, and low profile, and so on. The antenna adopts one quarter of wavelength, and utilizes the feeding way of microstrip to design 50 ohms of matching impedance, using the Finite Integration Technique method to calculate the distribution of surface electric current, radiation efficiency, radiation field and gains. Furthermore, two concepts are introduced in the design to improve characteristics of the antenna. First, partial radiators are lengthened to increase the radiation efficiency and impedance bandwidth of the antenna. Second, a parasitic element is placed near the antenna to generate parasitic resonance so as to increase matching impedance bandwidth. Last, for the sake of increasing the radiation efficiency of cellular tphones by controlling the nearby electromagnetic field around a human model, the periodic elements are employed to create a FSS (Frequency selective surface) array with the bandgap characteristic to suppress the propagation of the electromagnetic wave. The design of integrated mobile-phone PIFA antenna with FSS module, which can let the back-oriented radiation to be reduced, is contributive to increase the radiation efficiency and gains. It also has the effectiveness of mobile phones in reducing specific absorption rate (SAR) induced around a human head model, and maintains the antenna performance of mobile communications. Key Words : Planar Inverted-F Antenna, shield, Frequency selective surface

碩士<br>景文科技大學<br>電子工程系電腦與通訊碩士班<br>105<br>In this paper, we propose an open-loop coupled-structure PIFA antenna. We use the general traditional inverted-F-shaped antenna as the design basis, and then add a radiation path and parasitic element next to each other to obtain three resonant paths, where PIFA longer path is used to generate Low frequency resonance mode to provide LTE 700 band operation, while the other shorter path is used to generate high-frequency mode, to provide GSM 2500 band operation, increase the open loop coupling structure resonates out of the LAA3500 band, in the Traditional PIFA dual-frequency antenna design, because only a single short-circuit path in the high-frequency mode and low-frequency mode can only get a compromise between the short circuit length to control its low frequency and high frequency impedance bandwidth, the antenna in maintaining the original LTE And increases the resonant path of the LAA at the same time, increasing the antenna effect of the band by the open loop coupling antenna structure. Detailed antenna design and experimental data will be described and discussed in this paper.

yes<br>A novel miniaturized planar double inverted-F antenna is presented. The antenna design is based on the electromagnetic coupling of two air dielectric PIFA antennas, combined with a broadband rectangular plate feed structure to achieve ultra-wideband characteristics. The computed and experimental impedance bandwidths show good agreement over an UWB frequency band from 3.1 GHz to 10.6 GHz for |S11| < -10dB. The antenna is electrically small, with size 0.31 x 0.16 x 0.09 wavelengths at 3.1 GHz and 1.06 x 0.55 x 0.31 wavelengths at 10.6 GHz. The simulated and measured gain and radiation patterns show acceptable agreement and confirm that the antenna has appropriate characteristics for short range wireless applications.<br>MSCRC

碩士<br>景文科技大學<br>電子工程系電腦與通訊碩士班<br>105<br>This paper presents a miniaturized printed planar inverted-F antenna design for wireless sensor networks, which is suitable for use in Internet products or sensors. It also explores the space environment with metal reflectors and grounding effects. covering frequency bands for Wi-Fi 2.4GHz and 5GHz dual-band antenna. In this paper, the antenna design is in line with the actual industrial application, the use of metal reflector and wire grounding as experimental parameters, indicating the antenna structure and characteristics of the different changes in the height, and the antenna side of the ground and the bottom of the metal reflector and the practical application of the simulation industry, the grounding effect of the discussion and comparison. The results show that the miniaturized printing planar inverted F antenna with the application environment, the smallest size up to 1 by 1 square centimeter, to meet the industry application specifications, and the relevant research parameters can also be used as an industry reference.

碩士<br>國立彰化師範大學<br>電子工程學系<br>104<br>The main objective of this thesis is the study and design of balanced wideband filtering planar inverted-F antenna (PIFA) and balanced ultra-wideband (UWB) open-slot antenna with a 5-GHz notched band. For the first work, the integrated design of a balanced wideband filter and a PIFA is performed. The balanced wideband filter is constructed using parallel coupled-line resonators and the antenna is designed in inverted-F configuration. The improvement of the differential-mode (DM) passband selectivity and upper stopband rejection, as well as the increase of the common-mode (CM) rejection level are investigated. For the second circuit, the balanced UWB open-slot antenna is fed with a differential microstrip line which intersects the antenna at the position a quarter-wavelength away from the shorted end of the open-slot to achieve strong coupling. In addation, a 5-GHz notched band is implemented to avoid the interference with signals of the 5.2- and 5.8-GHz WLAN bands. Besides the design and investigation of the above balanced wideband/UWB antennas, this thesis also proposes a novel approach of measuring balanced antennas using conventional two-port antenna measurement systems. The formulas needed to convert the S parameters of the standard single-port antenna to those of the balanced antenna will be derived. The proposed approach will be validated by practical example circuits. The approximated balanced antenna measurement method is expected to be useful to researchers who own only a two-port antenna measurement system. It can not only provide an easy and convenient way for measuring balanced antennas, but also help save the cost needed for building a balanced antenna measurement system. This could be the biggest contribution of this thesis. Keywords—balanced wideband bandpass filter, balanced wideband PIFA, ultra-wideband (UWB), passband selectivity, common-mode suppression

碩士<br>大葉大學<br>電信工程學系碩士班<br>93<br>This thesis is aimed at designing embedded antennas that can be applied to mobile phones. The operating bands available for cellular communications may depend on the areas of operation. Therefore it is advantageous for a mobile phone to be capable of operating in multiple frequency bands. According to its capacity, a mobile phone can be categorized as dual-band (e.g., GSM850/PCS and GSM900/DCS), trip-band (e.g., GSM850/DCS/PCS and GSM900/DCS/PCS), and WCDMA, a third generation communication scheme. Four embedded antennas applicable to multiple-band mobile phones were designed and fabricated. They are either a monopole antenna or a printed inverted-F antenna (PIFA). Two methodologies were employed to perform the antenna design. First, a parasitic conductor was placed near the monopole to invoke parasitic resonance so as to increase the impedance bandwidth. Second, part of the copper on the ground plane under the PIFA was removed to increase the radiation efficiency and impedance bandwidth. All these antennas possess the features of low profile, low cost, ease of manufacture, and good radiation patterns in both co-polarized and cross-polarized directions. They also have bandwidths that are broad enough for mobile communications.

yes<br>Two miniature low profile PIFLA antennas with a compact volume size of 30mm × 15mm × 8mm has presented in this paper. By applying the magnetic wall concept a reduced size dual-band and a wideband half PIFLAs for WLAN (2.4GHz/5.2GHz) and UWB applications are achieved. The dual-band antenna shows a relative bandwidth of 12% and 10.2% at ISM2400 and IEEE802.11a frequency bands respectively for input return loss less than 10dB. By carefully tuning the geometry parameters of the dual-band proposed antenna, the two resonant frequencies can be merged to form a wide bandwidth characteristic, to cover 3000MHz to 5400 MHz bandwidth (57%) for a similar input return loss that is fully covering the lower band UWB (3.1-4.8GHz) spectrum. The experimental and simulated return losses on a small finite ground plane of size 30mm × 15mm show good agreement. The computed and measured radiation patterns are shown to fully characterize the performance of the proposed two antennas.<br>MSCRC

No<br>This study presents a miniaturised multiple input and multiple output /diversity antenna which is suitable for high data-rate communication systems such as mobile ultra-wideband (UWB). This antenna assembly comprises two identical planar inverted-F antennas, a T-shaped structure connecting them and a finite ground plane. The T-shaped structure improves the impedance matching and suppresses the mutual coupling between the antenna elements over a wider bandwidth than previously reported. The compact envelope dimension of this antenna is 50 x 90 x 7.5 mm(3). Theoretical and experimental S-parameters are illustrated for this antenna that fully cover the UWB operating frequency band of 3.1-10.6 GHz, with a reflection coefficient and mutual coupling better than -10 and -20 dB, respectively. Acceptable agreement is obtained between computed and measured radiation patterns, gains, envelope correlation coefficient and channel capacity loss. The proposed antenna is an attractive candidate to provide pattern diversity and enhance channel capacity in a rich scattering environment.

Yes<br>This paper examines the case for an ultrawideband planar inverted-F-L-antenna design intended for use in the lower sub-band. The antenna construction is based on the conventional inverted F, and inverted L as its feed element, and parasitic element, respectively. The optimized antenna size is 30×15×4mm3. The prototype antenna has a good return loss of -10 dB, and a 66.6% impedance bandwidth (2.8 GHz ¿ 5.6 GHz), the gain varies between 3.1 dBi and 4.5 dBi.

No<br>This article presents a printed crescent-shaped monopole MIMO diversity antenna for wireless communications. The port-to-port isolation is increased by introducing an I-shaped conductor symmetrically between the two antenna elements and shaping the ground plane. Both the computed and experimental results confirm that the antenna possesses a wide impedance bandwidth of 54.5% across 1.6-2.8 GHz, with a reflection coefficient and mutual coupling better than -10 and -14 dB, respectively. By further validating the simulated and the measured radiation and MIMO characteristics including far-field, gain, envelope correlation and channel capacity loss, the results show that the antenna can offer effective MIMO/diversity operation to alleviate multipath environments.