Journal articles: 'Missile Antennas'

1

Wang, Wei, Xue Tian Wang, Ying Li, and Song Song. "Design of an Ultra-Wideband Four Arms Sinuous Antenna." Advanced Materials Research 981 (July 2014): 469–73. http://dx.doi.org/10.4028/www.scientific.net/amr.981.469.

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Due to the advantages of ultra-wideband, single caliber, symmetric pattern, full polarization, the sinuous antennas have gradually displaced the traditional spiral antennas in the Missile guider, reflector feed, wideband direction finding system. Based on the traditional planar sinuous antennas, this paper designed a novel 2-22 GHz 3D sinuous antenna in the conical form. Results show that the designed antenna showed high performance within 2-22 GHZ frequency band.

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Gonçalves, André Paim, Renan Miranda Richter, Felipe Streitenberger Ivo, Alessandro Roberto Santos, Robson Ribeiro Carreira, and Olympio Lucchini Coutinho. "Proposal of anti-radiation missile decoy assisted by microwave photonics." Revista Brasileira de Aplicações de Vácuo 39, no. 3 (December 28, 2020): 218–23. http://dx.doi.org/10.17563/rbav.v39i3.1178.

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This article has proposed the concept of a decoy that could be used against anti-radiation missiles (ARMs). The bait signals are generated remotely and transmitted to the sacrificial antenna site over a fiber-optic network. This network has the possibility to support broadband radar signals in the range of a few GHz. This study postulated a distance of 1 km in relation to its park of antennas, distance that may be greater. This analog fiber link was designed for radar signal transmission in the frequency range of 0.3 to 3 GHz. The theoretical results were compared with the experimental ones, and it was observed that the behavior of the radar signal power gained in the studied range is straight. Thus, the signal does not present distortions. The system proposed in this study is promising as a distraction for ARMs.

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3

Vyas, Kirti, Garima Sanyal, Arun Kumar Sharma, and Pramod Kumar Singhal. "Gain enhancement over a wideband in CPW-fed compact circular patch antenna." International Journal of Microwave and Wireless Technologies 6, no. 5 (December 13, 2013): 497–503. http://dx.doi.org/10.1017/s1759078713001037.

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The present paper reports the gain enhancement over a wideband (12–15 GHz) in a coplanar waveguide (CPW)-fed circular patch antenna with circular defected ground structure (DGS). Two compact coplanar circular antennas have been designed and fabricated with and without DGS of same volume 18 × 20 × 1.6 mm3, built over FR4-epoxy substrate (εr = 4.4). Gain enhancement has been achieved by optimizing the current distribution with suitable DGS. For this purpose, structural designs have been optimized by parametric simulations in HFSS and CST MWS. Both the antennas can perform well in variety of wireless communication including WLAN IEEE 802.11 g/a (5.15–5.35 GHz and 5.725–5.825 GHz) and X-band applications including short range, tracking, missile guidance, and radar communication that ranges roughly from 8.29 to 11.4 GHz. The measured experimental results show that impedance bandwidth (S11 < −10 dB) of antenna with DGS is 100%. The antenna with DGS offers gain improvement by 2.7 dB for 13 GHz and 7 dB for 14 GHz. The performance of antenna with DGS is compared to conventional CPW-fed circular patch antenna (without DGS) in terms of reflection coefficient, radiation characteristics, and gain.

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Biswas, Diptiman, and Asif Rizwan. "Frustum Shaped Conformal Antenna for Spinning Aerial Platform." Defence Science Journal 68, no. 4 (June 26, 2018): 388. http://dx.doi.org/10.14429/dsj.68.12217.

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A novel approach to design and develop frustum shaped conformal antenna for transmission of telemetry data from a missile like spinning aerial platform is described. The requirement necessitates for an omni directional radiation pattern in the roll plane. However, the criteria is not feasible to achieve by using a monopole or a dipole as the omni coverage due to these antennas are restricted only in yaw or azimuth plane of the aerial platform. A conformal antenna appropriately wrapped on to the surface provides potential solution and accordingly has been configured for meeting the requirements of a practical application. The antenna artwork has been designed to conform to the exterior geometry of the intended portion of conical surface and printed on a microwave substrate which is essentially thin and flexible. A corporate feed distribution scheme has been designed and tailored to match with the impedance of the microstrip radiator at multiple locations and also printed along with it making the frustum antenna very compact and of aerodynamic supportive form. The antenna produces required omni coverage in the plane normal to the roll axis. A step-wise method for the design and development of the frustum conformal antenna through simulation and experiment approach has been discussed.

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5

Andreev, А. "Outlook for application of radars with phased-array antennas in foreign navies on missile tracking ships." Transactions of the Krylov State Research Centre 3, no. 385 (August 27, 2018): 145–52. http://dx.doi.org/10.24937/2542-2324-2018-3-385-145-152.

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6

Lohn, Jason D., Gregory S. Hornby, and Derek S. Linden. "Human-competitive evolved antennas." Artificial Intelligence for Engineering Design, Analysis and Manufacturing 22, no. 3 (June 12, 2008): 235–47. http://dx.doi.org/10.1017/s0890060408000164.

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AbstractWe present a case study showing a human-competitive design of an evolved antenna that was deployed on a NASA spacecraft in 2006. We were fortunate to develop our antennas in parallel with another group using traditional design methodologies. This allowed us to demonstrate that our techniques were human-competitive because our automatically designed antenna could be directly compared to a human-designed antenna. The antennas described below were evolved to meet a challenging set of mission requirements, most notably the combination of wide beamwidth for a circularly polarized wave and wide bandwidth. Two evolutionary algorithms were used in the development process: one used a genetic algorithm style representation that did not allow branching in the antenna arms; the second used a genetic programming style tree-structured representation that allowed branching in the antenna arms. The highest performance antennas from both algorithms were fabricated and tested, and both yielded very similar performance. Both antennas were comparable in performance to a hand-designed antenna produced by the antenna contractor for the mission, and so we consider them examples of human-competitive performance by evolutionary algorithms. Our design was approved for flight, and three copies of it were successfully flown on NASA's Space Technology 5 mission between March 22 and June 30, 2006. These evolved antennas represent the first evolved hardware in space and the first evolved antennas to be deployed.

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7

Tan, Chee Leong, and Hooman Mohseni. "Emerging technologies for high performance infrared detectors." Nanophotonics 7, no. 1 (January 1, 2018): 169–97. http://dx.doi.org/10.1515/nanoph-2017-0061.

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AbstractInfrared photodetectors (IRPDs) have become important devices in various applications such as night vision, military missile tracking, medical imaging, industry defect imaging, environmental sensing, and exoplanet exploration. Mature semiconductor technologies such as mercury cadmium telluride and III–V material-based photodetectors have been dominating the industry. However, in the last few decades, significant funding and research has been focused to improve the performance of IRPDs such as lowering the fabrication cost, simplifying the fabrication processes, increasing the production yield, and increasing the operating temperature by making use of advances in nanofabrication and nanotechnology. We will first review the nanomaterial with suitable electronic and mechanical properties, such as two-dimensional material, graphene, transition metal dichalcogenides, and metal oxides. We compare these with more traditional low-dimensional material such as quantum well, quantum dot, quantum dot in well, semiconductor superlattice, nanowires, nanotube, and colloid quantum dot. We will also review the nanostructures used for enhanced light-matter interaction to boost the IRPD sensitivity. These include nanostructured antireflection coatings, optical antennas, plasmonic, and metamaterials.

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8

Hornby, Gregory S., Jason D. Lohn, and Derek S. Linden. "Computer-Automated Evolution of an X-Band Antenna for NASA's Space Technology 5 Mission." Evolutionary Computation 19, no. 1 (March 2011): 1–23. http://dx.doi.org/10.1162/evco_a_00005.

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Whereas the current practice of designing antennas by hand is severely limited because it is both time and labor intensive and requires a significant amount of domain knowledge, evolutionary algorithms can be used to search the design space and automatically find novel antenna designs that are more effective than would otherwise be developed. Here we present our work in using evolutionary algorithms to automatically design an X-band antenna for NASA's Space Technology 5 (ST5) spacecraft. Two evolutionary algorithms were used: the first uses a vector of real-valued parameters and the second uses a tree-structured generative representation for constructing the antenna. The highest-performance antennas from both algorithms were fabricated and tested and both outperformed a hand-designed antenna produced by the antenna contractor for the mission. Subsequent changes to the spacecraft orbit resulted in a change in requirements for the spacecraft antenna. By adjusting our fitness function we were able to rapidly evolve a new set of antennas for this mission in less than a month. One of these new antenna designs was built, tested, and approved for deployment on the three ST5 spacecraft, which were successfully launched into space on March 22, 2006. This evolved antenna design is the first computer-evolved antenna to be deployed for any application and is the first computer-evolved hardware in space.

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9

Ge, Lei, Xujun Yang, Zheng Dong, Dengguo Zhang, and Xierong Zeng. "Reconfigurable Magneto-Electric Dipole Antennas for Base Stations in Modern Wireless Communication Systems." Wireless Communications and Mobile Computing 2018 (2018): 1–8. http://dx.doi.org/10.1155/2018/2408923.

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Magneto-electric (ME) dipole antennas, with the function of changing the antenna characteristics, such as frequency, polarization, or radiation patterns, are reviewed in this paper. The reconfigurability is achieved by electrically altering the states of diodes or varactors to change the surface currents distributions or reflector size of the antenna. The purpose of the designs is to obtain agile antenna characteristics together with good directive radiation performances, such as low cross-polarization level, high front-to-back ratio, and stable gain. By reconfiguring the antenna capability to support more than one wireless frequency standard, switchable polarizations, or cover tunable areas, the reconfigurable ME dipole antennas are able to switch functionality as the mission changes. Therefore, it can help increase the communication efficiency and reduce the construction cost. This shows very attractive features in base station antennas of modern wireless communication applications.

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10

Kogan, L. R. "Position Angle of the HALCA Antenna Feed." International Astronomical Union Colloquium 164 (1998): 419–20. http://dx.doi.org/10.1017/s0252921100046224.

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AbstractKnowledge of the position angle of an antenna feed is very important for polarization observations. The issue had been developed for ground based antennas but has not been considered for a orbiting antennas. We provide a calculation of the position angle of the Japanese satellite VSOP/HALCA which was successfully launched in a space VLBI mission.

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11

Bachmann, Markus, Marco Schwerdt, Gabriel Castellanos Alfonzo, and Dirk Schrank. "Phase Pattern Calibration for Interferometric Applications in Spaceborne SAR Systems." International Journal of Antennas and Propagation 2013 (2013): 1–8. http://dx.doi.org/10.1155/2013/284698.

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SAR is a widely used technique to acquire images for geoscience and earth observation applications. Active phased array antennas are commonly used in spaceborne SAR systems. For certain modes and applications, it is necessary to know the phase behavior of these phased array antennas. For applications utilizing the different polarization channels for interferometry, the phase difference between the polarizations needs to be calibrated very accurately as it is the main evaluation parameter. Also for single-pass interferometric missions, the difference between the two antennas in terms of phase gradients is of major importance. This paper demonstrates for the first time the usage of phase patterns in an operational interferometric SAR mission. It describes why these phase patterns are required and how they are used to fulfill the different goals of the missions. Then, the mathematical model to derive the phase of the antenna patterns is shown. Finally, the paper explains how the antenna patterns are calibrated in order to minimize their residual errors and describes in detail the measurements performed for this calibration and verification.

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12

Maccone, Claudio. "Seti Space Missions." International Astronomical Union Colloquium 161 (January 1997): 761–76. http://dx.doi.org/10.1017/s0252921100015372.

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AbstractSETI from space is currently envisaged in three ways: i) by large space antennas orbiting the Earth that could be used for both VLBI and SETI (VSOP and RadioAstron missions), ii) by a radiotelescope inside the Saha far side Moon crater and an Earth-link antenna on the Mare Smythii near side plain. Such SETIMOON mission would require no astronaut work since a Tether, deployed in Moon orbit until the two antennas landed softly, would also be the cable connecting them. Alternatively, a data relay satellite orbiting the Earth-Moon Lagrangian pointL2would avoid the Earthlink antenna, iii) by a large space antenna put at the foci of the Sun gravitational lens: 1) for electromagnetic waves, the minimal focal distance is 550 Astronomical Units (AU) or 14 times beyond Pluto. One could use the huge radio magnifications of sources aligned to the Sun and spacecraft; 2) for gravitational waves and neutrinos, the focus lies between 22.45 and 29.59 AU (Uranus and Neptune orbits), with a flight time of less than 30 years. Two new space missions, of SETI interest if ET’s use neutrinos for communications, are proposed.

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13

Reimann, Jens, Marco Schwerdt, Kersten Schmidt, Patrick Klenk, Ulrich Steinbrecher, and Helko Breit. "Precise Antenna Pointing Determination in Elevation for Spaceborne SAR Systems Using Coherent Pattern Differences." Remote Sensing 11, no. 3 (February 6, 2019): 320. http://dx.doi.org/10.3390/rs11030320.

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The precise determination of the SAR (synthetic aperture radar) antenna pointing is an essential task initially performed during the commissioning phase of a spaceborne SAR system and is permanently monitored during the whole mission life-time. Besides a correct illumination of the scene during data acquisition, antenna pointing is required for proper compensation of the radiation pattern for radiometric correction during SAR data processing. The Amazon rainforest is a well-established target area for antenna pointing estimation in elevation as proven by many past and current SAR missions. Several new SAR systems are now proposed which are using long wavelengths, i.e., L- and P-bands, which will be implemented using reflector-based antenna systems. These reflectors have, in contrast to planar phased array antennas, no completely rigid connection to the satellite body and, hence, a more volatile antenna pointing. Due to the huge dimensions of such reflector antennas required for the envisaged long wavelengths and the finite stiffness of the boom, the antenna pointing may change significantly along the orbit. Such variation cannot be tracked using the common Amazon rainforest approach only, as this measurement opportunity exists only at two positions along the orbit (ascending and descending). Here, the performance of an alternative technique is presented which mitigates the influence of the underlying SAR scene by employing two coherent SAR datasets acquired simultaneously with different antenna patterns. This allows the use of amplitude and phase information for pointing estimation. No assumption upon the homogeneity of the underlying scene is required and, hence, pointing estimation becomes feasible at nearly any point along the orbit. This paper outlines the technique, describes simulation results and presents outcomes from first experimental acquisitions performed with the TerraSAR-X satellite.

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14

Saidulu, V. "Design a 900 Hybrid Feed Square Patch Stacked Antenna at 3GHz." International Journal of Engineering and Advanced Technology 10, no. 3 (February 28, 2021): 201–5. http://dx.doi.org/10.35940/ijeat.c2279.0210321.

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Microstrip antennas find wide applications in high-speed vehicles, and missiles, tanks, satellite communications etc. The main advantage of these antennas over conventional microwave antenna are lightweight, low volume, low cost, planar structure and compatibility with integrated circuits. The present paper deals with the design and development of 90o hybrid feed square patch stacked antenna. The design of square patch and 900 hybrid feed has been carried out at frequency of 3 GHz on epoxy glass substrate, the radiation pattern of the square patch has been experimentally studied. The effect of stacked patches placed above the square patch has been studied experimentally for different cases like 1,2,3 and 4 stacked patches placed one above other above the driven square patch. From the experimental result it has been found that performance of the case of 1 + 2 (one driven element and two parasitic element) is optimum with bandwidth of 16 % and VSWR 1.42 the performance degrades the no of practical elements is increased that is for case 1 + 3 and 1 + 4 etc., The performance of 1 + 2 case of also found to be superior to the performance 1+ 0 and 1+1 cases experimentally studied, also been carried out for cross Polarization and co – polarization.

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15

Lu, Wei, Yuxi Li, Yicai Ji, Chuanjun Tang, Bin Zhou, and Guangyou Fang. "Ultra-Wideband MIMO Array for Penetrating Lunar Regolith Structures on the Chang’e-5 Lander." Electronics 10, no. 1 (December 23, 2020): 8. http://dx.doi.org/10.3390/electronics10010008.

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The Chang’e-5 lunar exploration mission of China is equipped with a Lunar Regolith Penetrating Radar (LRPR) for measuring the thickness and structures of the lunar regolith in the landing area. Since the LRPR is stationary, an ultra-wideband multiple-input multiple-output (MIMO) array is designed as a replacement for conventional mobile subsurface probing systems. The MIMO array, with 12 antenna elements and a switch matrix, operates in the frequency band from 1.0 to 4.75 GHz. In this work, the design and layout of the antenna elements were optimized with respect to the lander. To this end, the antenna elements were designed as miniaturized Vivaldi antennas with quarter elliptical slots (i.e., quarter elliptical slotted antenna, or QESA). QESAs are significantly small while being able to mitigate the impact of the lander on antenna electrical performances. QESAs also have a wide operating bandwidth, flat gain, and excellent time domain characteristics. In addition, a high-temperature resistant ultra-light radome with high transmissivity is designed to protect the external antenna array. After calibration, the MIMO array is used to detect targets embedded in volcanic ash. The detection depth reaches 2.5 m, and the detection effect is good.

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Choi, Yu-Seong, Jeong-Su Park, and Wang-Sang Lee. "Beam-Reconfigurable Multi-Antenna System with Beam-Combining Technology for UAV-to-Everything Communications." Electronics 9, no. 6 (June 12, 2020): 980. http://dx.doi.org/10.3390/electronics9060980.

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This paper proposes a beam-reconfigurable antenna for unmanned aerial vehicles (UAVs) with wide beam coverage by applying beam-combining technology to multiple antennas with different beam patterns. The proposed multi-antenna system consists of a circular patch antenna and a low-profile printed meandered monopole antenna. For beam combining, a coplanar waveguide with ground (CPW-G) structure feeding network is proposed, and it consists of two input ports, a 90° hybrid coupler, a microstrip 90° phase delay line, and a single-pole double-throw (SPDT) switch. It performs the role of power distribution and phase adjustment, and synthesizes the broad-side beam of the monopole antenna and the end-fire beam of the patch antenna to form the directive broadside beams in four different directions. The proposed antenna system operates at 5–5.5 GHz which covers both UAV ground control frequencies (5.03–5.09 GHz) and UAV mission frequencies (5.091–5.150 GHz). The peak gain, total efficiency, and half-power beamwidth (HPBW) of the antenna system are approximately 5.8 dBi, 76%, 145° in the elevation plane, and 360° in the azimuth plane respectively. Its electrical size and weight are λ 0 × λ 0 × 0.21 λ 0 at 5.09 GHz and 19.2 g, respectively.

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17

Ishitsuka, José, M. Ishitsuka, N. Kaifu, M. Inoue, M. Tsuboi, M. Ohishi, T. Kondo, et al. "A new astronomical facility for Peru: transforming a telecommunication's 32-metre antenna into a radio-telescope." Proceedings of the International Astronomical Union 2, SPS5 (August 2006): 77–82. http://dx.doi.org/10.1017/s1743921307006758.

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AbstractIn 1984 an INTELSAT antenna of 32 m of diameter was constructed at 3 370 metres above the sea level on the Peruvian Andes. At the time Entel Perú the Peruvian tele-communications company managed the antenna station, of almost 12 hectares in extension. In 1993 the government transferred the station to the private telecommunications company Telefónica del Perú. Since transoceanic fiber optics replaced radically satellite communications in 2002, a beautiful 32- metre parabolic antenna was finished its tele-communications mission and become available for other use. So in cooperation with the National Astronomical Observatory of Japan we began coordination to transform the antenna into a radio-telescope.Researches on interstellar medium around Young Stellar Objects (YSO) are possible using methanol maser that emits at 6.7 GHz, so initially we will monitor and survey maser sources at the southern sky. An ambient temperature receiver withTrx= 60 K was developed at Nobeyama Radio Observatory and is ready to be installed. The antenna will be controlled by the Field System FS9 software installed in a PC within a Linux environment. An interface between antenna and PC was developed at Kashima Space Research Center in Japan by Mr E. Vidal.In the near future S-band (2 GHz), X-band (8GHz), 12 GHz and 22 GHz observations are planned.The peculiar position and altitude of the Peruvian Radio Observatory will be useful for VLBI observations with the VLBA for astronomical observation and geodetic measurements. For Peru where few or almost non astronomical observational instruments are available for research, implementation of the first radio observatory is a big step to foster sciences at graduate and postgraduate levels of universities.Worldwide tele-communications antennas recently tend to finish their role as tele-communications antennas. Several of them are transformed into useful observational instruments.

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18

Wu, Junyan, Jiaao Yu, and Qin Tao. "Design of a Missile-borne Conformal Microstrip Navigation Antenna." MATEC Web of Conferences 232 (2018): 04080. http://dx.doi.org/10.1051/matecconf/201823204080.

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A missile-borne conformal dual-fed circular polarized microstrip antenna array is designed and fabricated, which realized omnidirectional radiation in horizontal direction. Frequencies of the antenna include GPS L1 frequency (1.575GHz) and Beidou navigation system B1 frequency (1.562GHz). Based on the HFSS simulation, the influence of conformation is analyzed on S11, axial ratio and gain of antenna array. The size of microstrip patches is changed so that the influence of conformation on antenna can be reduced. The circular polarization performance and the circular polarization gain of the antenna are also improved. The antenna array prototype is fabricated and measured. The result shows that the S11 parameter of the antenna is less than -10dB in the 1.55~1.60GHz frequency band. At the GPS L1 frequency and the Beidou B1 frequency, the maximum of horizontal omnidirectional gain is 1.73dB, 1.25dB respectively. The out-of-roundness of the radiation pattern is less than 2.5dB. The antenna has a good horizontal omnidirectional circular polarization radiation performance.

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19

Monthasuwan, Jessada, Thanaset Thosdeekoraphat, and Chanchai Thongsopa. "Design of Curved Patch Array Antenna for Small Missile Application." Applied Mechanics and Materials 378 (August 2013): 487–91. http://dx.doi.org/10.4028/www.scientific.net/amm.378.487.

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The design of curved patch array antenna for small missile application is presented. A thin copper plate antenna was attached a part of plastic pipe. This antenna is designed on cylinder metal object for such an application in military communication devices and antenna analysis was conducted by using the CST program. The frequency of a designed antenna was adjusted at 2.4 GHz. The proposed antenna is realized and experimentally examined, since it is small size, light weight, easy method fabrication and low manufacturing cost. In measurement, it is found that the propose antenna have the return loss was lower than-10 dB which covered frequency range 2.3 GHz-2.7 GHz. The average gain achieved in the propose antenna is about 6.13 dB over the operating frequency. The advantage of the proposed antenna is that it can be used to small missile for military application.

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20

Sampl, M., W. Macher, C. Gruber, T. Oswald, M. Kapper, H. O. Rucker, and M. Mogilevsky. "HF performance of electric field sensors aboard the RESONANCE satellite." Geoscientific Instrumentation, Methods and Data Systems Discussions 4, no. 2 (December 18, 2014): 683–703. http://dx.doi.org/10.5194/gid-4-683-2014.

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Abstract. We present the high frequency properties of the eight electric field sensors as proposed to be launched on the spacecraft "RESONANCE" in the near future. Due to the close proximity of the conducting spacecraft body, the sensors (antennas) have complex receiving features and need to be well understood for an optimal mission and spacecraft design. An optimal configuration and precise understanding of the sensors and antennas characteristics is also vital for the proper performance of spaceborne scientific instrumentation and the corresponding data analysis. The provided results are particularly interesting with regard to the planned mutual impedance experiment for measuring plasma parameters. Our computational results describe the extreme dependency of the sensor system regarding wave incident direction and frequency, and provides the full description of the sensor system as a multi-port scatterer. In particular, goniopolarimetry techniques like polarization analysis and direction finding depend crucially on the presented antenna characteristics.

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21

Szpakowska-Peas, Ewelina. "CRW 13 – the new generation radio altimeter: the concept, design, and tests." Aircraft Engineering and Aerospace Technology 92, no. 9 (June 4, 2020): 1413–19. http://dx.doi.org/10.1108/aeat-12-2019-0238.

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Purpose The purpose of this paper is to outline a novel concept of radio altimeter CRW-13 that has been designed and developed in the Lukasiewicz Research Network – Institute of Aviation as a result of the need to update the outdated structure of RWL-750M. Design/methodology/approach The new design of the device consists of integral antennas and signal processor for smart digital signal filtering. Findings As a result of a number of laboratory tests and flight tests of the device installed on MP-02 “Czajka” ultralight aircraft promising results were achieved. They allow to move on to the next stage of implementation and preparation for the device certification. Practical implications The CRW-13 meets with great interest of civilian and military potential customers. It is an ideal solution for airplanes, helicopters, unmanned and guided missiles. The universal design enables installation on many different platforms where exact height measurement is needed and crucial. Originality/value At the origin of the new concept was the need to replace the separate transmitting and receiving antennas with one unit comprising two planar microstrip antennas placed directly next to each other on a common plate block in the transceiver. This solution eliminates thick antenna cables and coaxial connectors, which are the most unreliable and problematic elements of radio altimeters. The new concept of integral antennas and the use of signal processors for smart digital signal filtration made it possible to take the technology to the next level.

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Nekrasov, Alexey, Alena Khachaturian, Ján Labun, Pavol Kurdel, and Mikhail Bogachev. "Towards the Sea Ice and Wind Measurement by a C-Band Scatterometer at Dual VV/HH Polarization: A Prospective Appraisal." Remote Sensing 12, no. 20 (October 16, 2020): 3382. http://dx.doi.org/10.3390/rs12203382.

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Following the mission science plan of EPS/Metop-SG C-band scatterometer for 2023–2044, we consider the potential application of the sea ice/water discrimination method based on the minimum statistical distance of the measured normalized radar cross sections (NRCS) to the geophysical model functions (GMF) of the sea ice and water, respectively. The application of the method is considered for the classical spacecraft scatterometer geometry with three fixed fan-beam antennas and the hypothetical prospective scatterometer geometry with the five fixed fan-beam antennas. Joint vertical (VV) and horizontal (HH) transmit and receive polarization are considered for the spaceborne scatterometer geometries. We show explicitly that the hypothetical five fixed fan-beam antenna geometry combined with the dual VV and HH polarization for all antennas provides better estimates of the sea wind speed and direction as well as sea ice/water discrimination during single spacecraft pass. The sea ice/water discrimination algorithms developed for each scatterometer geometry and dual VV/HH polarization are presented. The obtained results can be used to optimize the design of new spaceborne scatterometers and will be beneficial to the forthcoming satellite missions.

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23

Smetana, Adam. "Background for gravitational wave signal at LISA from refractive index of solar wind plasma." Monthly Notices of the Royal Astronomical Society: Letters 499, no. 1 (September 16, 2020): L77—L81. http://dx.doi.org/10.1093/mnrasl/slaa155.

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ABSTRACT A strong indication is presented that the space-based gravitational antennas, in particular the Laser Interferometer Space Antenna (LISA) concept introduced in 2017 in response to the ESA call for L3 mission concepts, are going to be sensitive to a strong background signal interfering with the prospected signal of gravitational waves. The false signal is due to variations in the electron number density of the solar wind, causing variations in the refractive index of plasma flowing through interplanetary space. As countermeasures, two solutions are proposed. The first solution is to deploy enough solar wind detectors to the LISA mission to allow for reliable knowledge of the solar wind background. The second solution is to equip the LISA interferometer with a second laser beam with a distinct wavelength to allow cancelling of the background solar wind signal from the interferometric data.

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24

Sampl, M., W. Macher, C. Gruber, T. Oswald, M. Kapper, H. O. Rucker, and M. Mogilevsky. "High-frequency performance of electric field sensors aboard the RESONANCE satellite." Geoscientific Instrumentation, Methods and Data Systems 4, no. 1 (May 4, 2015): 81–88. http://dx.doi.org/10.5194/gi-4-81-2015.

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Abstract. We present the high-frequency properties of the eight electric field sensors as proposed to be launched on the spacecraft "RESONANCE" in the near future. Due to the close proximity of the conducting spacecraft body, the sensors (antennas) have complex receiving features and need to be well understood for an optimal mission and spacecraft design. An optimal configuration and precise understanding of the sensor and antenna characteristics is also vital for the proper performance of spaceborne scientific instrumentation and the corresponding data analysis. The provided results are particularly interesting with regard to the planned mutual impedance experiment for measuring plasma parameters. Our computational results describe the extreme dependency of the sensor system with regard to wave incident direction and frequency, and provides the full description of the sensor system as a multi-port scatterer. In particular, goniopolarimetry techniques like polarization analysis and direction finding depend crucially on the presented antenna characteristics.

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25

Senthil Kumar, S., and G. Anitha. "A Novel Self-Tuning Fuzzy Logic-Based PID Controllers for Two-Axis Gimbal Stabilization in a Missile Seeker." International Journal of Aerospace Engineering 2021 (January 13, 2021): 1–12. http://dx.doi.org/10.1155/2021/8897556.

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Tracking a target is an essential function of a seeker for missiles. The target tracking mechanism of a seeker consists of gimbals, mounted with gyroscopes, and an antenna or some other energy receiving devices such as radar, infrared (IR), or laser. Stabilization of such a gimbal is necessary for any guided missile to maintain the tracking device always pointing towards the target. For the stabilization of the gimbal system, several control methods have been employed for making the gimbal to follow an input rate command by eliminating all the gimbal disturbances. Here, a new self-tuning fuzzy logic-based proportional, integral, derivative (PID) controller is introduced for the stabilization of a two-axis gimbal for a manoeuvring guided missile. The proposed control method involves tuning the gains of the PID controller based on the fuzzy logic rule bases considering the missile body rotation. The performance of the stabilization loops has been verified through MATLAB simulations for fuzzy logic-based PID controller compared with the conventional PID controller. The simulation results show the response of the gimbal system with stabilization loops met the control requirements with fuzzy PID controllers but not with conventional PID controllers.

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Hoseini, Sayed Amir, Jahan Hassan, Ayub Bokani, and Salil S. Kanhere. "In Situ MIMO-WPT Recharging of UAVs Using Intelligent Flying Energy Sources." Drones 5, no. 3 (September 5, 2021): 89. http://dx.doi.org/10.3390/drones5030089.

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Unmanned Aerial Vehicles (UAVs), used in civilian applications such as emergency medical deliveries, precision agriculture, wireless communication provisioning, etc., face the challenge of limited flight time due to their reliance on the on-board battery. Therefore, developing efficient mechanisms for in situ power transfer to recharge UAV batteries holds potential to extend their mission time. In this paper, we study the use of the far-field wireless power transfer (WPT) technique from specialized, transmitter UAVs (tUAVs) carrying Multiple Input Multiple Output (MIMO) antennas for transferring wireless power to receiver UAVs (rUAVs) in a mission. The tUAVs can fly and adjust their distance to the rUAVs to maximize energy transfer gain. The use of MIMO antennas further boosts the energy reception by narrowing the energy beam toward the rUAVs. The complexity of their dynamic operating environment increases with the growing number of tUAVs and rUAVs with varying levels of energy consumption and residual power. We propose an intelligent trajectory selection algorithm for the tUAVs based on a deep reinforcement learning model called Proximal Policy Optimization (PPO) to optimize the energy transfer gain. The simulation results demonstrate that the PPO-based system achieves about a tenfold increase in flight time for a set of realistic transmit power, distance, sub-band number and antenna numbers. Further, PPO outperforms the benchmark movement strategies of “Traveling Salesman Problem” and “Low Battery First” when used by the tUAVs.

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Choi, Dong-Su, Yoon-Seon Choi, Jae-Yeop Jeong, Tae-Hwan Jung, and Jong-Myung Woo. "Four-Array Printed Monopole Yagi-Uda Antenna Mounted on a Small Missile Warhead." Journal of Electromagnetic Engineering and Science 21, no. 2 (April 30, 2021): 143–47. http://dx.doi.org/10.26866/jees.2021.21.2.143.

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In this study, the structure of a circular four-array antenna was designed for a monopulse radar attached to a conical small missile warhead with a diameter of 29 mm and a lateral length of 63 mm. A printed monopole Yagi-Uda antenna was adopted as the basic model for the antenna to decrease production cost and reduce weight. The director structure of the printed monopole Yagi-Uda antenna that we proposed was modified to λ/2 to improve the beam direction. Unlike the existing structure, the proposed director was made to be separated from the ground, so that it could act as a director. The antenna was expanded to a four-array structure for the detection of vertical and horizontal planes. As a result of the design, the S11 had excellent matching characteristics at the center frequency of 9.375 GHz, and the beam pattern also had directivity in the same direction as the missile travel direction. In the case of gain, it showed more than 6 dBi performance. Finally, the proposed four-array structure antenna was fabricated to verify that the S11 and radiation patterns were maintained.

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Bachmann, Markus, Marco Schwerdt, and Benjamin Bräutigam. "Accurate Antenna Pattern Modeling for Phased Array Antennas in SAR Applications—Demonstration on TerraSAR-X." International Journal of Antennas and Propagation 2009 (2009): 1–9. http://dx.doi.org/10.1155/2009/492505.

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The high flexibility and tight accuracy requirements of today's spaceborne synthetic aperture radar (SAR) systems require innovative technologies to calibrate and process the SAR images. To perform accurate pattern correction during SAR processing, an Antenna Model is used to derive the multitude of different antenna beams generated by active antenna steering. The application of such an Antenna Model could be successfully demonstrated for the TerraSAR-X mission, launched in 2007. The methodology and the results of the inorbit verification with an achieved accuracy of better than dB is reviewed in this paper in detail showing its outstanding accuracy.

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Alekseev, V. R. "Two new Eucyclops species (Cyclopiformes: Cyclopidae) from Spain." Zoosystematica Rossica 19, no. 2 (December 30, 2010): 171–78. http://dx.doi.org/10.31610/zsr/2010.19.2.171.

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Eucyclops miracleae sp. nov. from the Albufera Mediterranean lagoon, and Eucyclops romaniensis sp. nov. from a spring in the vicinity of Valencia, both from Spain, are described. These new species belong to the serrulatus group because of the structure of the antennula possessing a smooth hyaline plate on three distal segments and the antenna bearing a group of hair-like setae on the top of the anterior side of the antennal basis. The new species are clearly distinguishable from the type species of the genus, E. serrulatus (Fischer, 1851), by missing a gap between hair-like setae on the outer side of the P4 coxal spine. A key for Eucyclops species inhabiting surface and subterranean waters of Europe is given.

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Esmaeilkhah, A., and N. Lavasani. "Jamming Efficacy of Variable Altitude GPS Jammer against Airborne GPS Receiver, Theoretical Study and Parametric Simulation." Advanced Electromagnetics 7, no. 1 (February 10, 2018): 57–64. http://dx.doi.org/10.7716/aem.v7i1.659.

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Satellite-based navigation systems, as one of the key infrastructure of development in manned and unmanned guidance systems, is vulnerable against the simplest form of attack in Electronic Warfare environments. This led us to investigate the described vulnerability of an airborne GPS receiver against jammers which are located at various altitude above the targeted point. To do that and to avoid encountering with unavailability of classified information about military-class missiles, some simplification was done and the problem was investigated in “Worst Case” conditions. Finally, the flight profile and radiation pattern of the antenna of the GPS receiver were theoretically modeled. Considering some assumptions, the other parameters were derived from them. At the end, a simulation software was developed and some results were extracted. The data was represented figuratively and the dependency of efficacy of jamming operation to the jammer’s altitude and flight profile of the missile were discussed.

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Kanso, A., R. Chantalat, U. Naeem, H. Chreim, M. Thevenot, S. Bila, and T. Monediere. "Multifeed EBG Dual-Band Antenna for Spatial Mission." International Journal of Antennas and Propagation 2011 (2011): 1–14. http://dx.doi.org/10.1155/2011/190358.

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We present the design of a multibeam reflector antenna fed by a multifeed dual-band electromagnetic band gap (EBG) antenna to achieve a high-gain multispot coverage for space applications. First, we design a dual-band EBG antenna in monofeed configuration. This antenna is composed of double-layer frequency selective surfaces (FSSs) arranged in the longitudinal direction and a square horn as a feed. Then, the same antenna in multifeed configuration is studied, and the results are compared to those obtained in monofeed configuration in order to emphasize the problem of coupling, generally encountered in multifeed configuration. Consequently, filters are used in order to reduce the parasitic interferences and obtain good radiation characteristics. As shown in this paper, the same EBG phase center is obtained in both frequency bands. Finally, we have studied the whole system composed of the offset reflector and the multifeed EBG dual-band antenna. An edge of coverage (EOC) gain higher than 42 dBi and sidelobes levels lower than −18 dBi are obtained over all spots.

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Nugroho, Gesang, and Dicky Dectaviansyah. "Design, manufacture and performance analysis of an automatic antenna tracker for an unmanned aerial vehicle (UAV)." Journal of Mechatronics, Electrical Power, and Vehicular Technology 9, no. 1 (July 31, 2018): 32. http://dx.doi.org/10.14203/j.mev.2018.v9.32-40.

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In conducting a disaster monitoring mission, an unmanned aerial vehicle (UAV) has to travel a long distance to cover the region that is hited by a disaster. In the monitoring mission, Air Data and Attitude Heading Reference System (ADAHRS) data are very important to always be displayed on the ground control station (GCS). Unfortunately, the area of monitoring mission is very wide, whereas the usage of an omnidirectional antenna in the disaster monitoring mission is limited to the UAV maximum range. Therefore, a high gain directional antenna is needed. However, the directional antenna has a disadvantage of always being directed to the target. To solve this problem, antenna tracker is made to track the UAV continuously so that the directional antenna can always be directed to the flying UAV. An antenna tracker using a 32-bit microcontroller and GPS with two degrees-of-freedom was developed. It is able to move 360 degrees on azimuth axis (yaw) and 90 degrees on elevation axis (pitch). Meanwhile, the directional antenna is three elements yagi type with a radiation capability of 6 dBi. By using the antenna tracker, larger UAV range was obtained and the connection between the UAV and the GCS could always be maintained with a minimum fluctuation of RSSI signal, compared to those without using antenna tracker.

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Litovchenko, I. D., A. V. Alakoz, V. I. Kostenko, S. F. Lihachev, A. M. Finkelstein, and A. V. Ipatov. "OH maser observations using the Russian interferometric network “Quasar” in preparation for scientific observations with the space mission RadioAstron." Proceedings of the International Astronomical Union 8, S287 (January 2012): 504–5. http://dx.doi.org/10.1017/s1743921312007612.

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AbstractWe present results of a VLBI experiment at a wavelength of 18 cm, which simulates the ground-space interferometer with space link to RadioAstron. An array of five antennas was used, four of them are located in the Russian Federation, plus the the 32-m radio telescope in Medicine (Italy). The 22-m radio telescope in Pushchino (Moscow Region) acted in place of the space arm. It has an effective area of 100 square meters. The three other Russian 32-m antennas are operated by the Institute of Applied Astronomy RAS; they are located at Badary, Svetloe and Zelenchukskaya (interferometer network “Quasar”). The maximum base-line, Badary-Svetloe, was about 4402 km, providing an angular resolution of about 0.009 arc seconds at a wavelength of 18 cm. The duration of the experiment was 10 hours on 02/03 February 2011. The program of observations included quasars 3C273, 3C279, 3C286 and the maser source - W3(OH). W3(OH) was observed only by the Russian telescopes and was investigated at the frequency of the 1665 MHz main line. The data were recorded on the MK5 recorder (32-m radio telescopes) and the RDR system (RadioAstron Digital Recorder) in Pushchino. The low SEFD (system equivalence of flux density) of Pushchino emulated the RadioAstron antenna. Correlation was performed with the universal software correlator of the AstroSpace Center of Lebedev Physical Institute. The correlator output format is compatible with that used by the AIPS package, which was used for data analysis. After analyzing the correlated data we obtained relative coordinates of the maser components. The main results are tabulated and presented in the figures. The data quality is sufficient for astrophysical analysis and comparison with previous observations of maser source W3(OH) on VLBI networks EVN and VLBA.

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Kim, Young-Rok, Young-Joo Song, Jonghee Bae, and Bang-Yeop Kim. "Influence of the Choice of Lunar Gravity Model on Orbit Determination for Lunar Orbiters." Mathematical Problems in Engineering 2018 (2018): 1–17. http://dx.doi.org/10.1155/2018/5145419.

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We examine the influence of the lunar gravity model on the orbit determination (OD) of a lunar orbiter operating in a 100 km high, lunar polar orbit. Doppler and sequential range measurements by three Deep Space Network antennas and one Korea Deep Space Antenna were used. For measurement simulation and OD analysis, STK11 and ODTK6 were utilized. GLGM2, LP100K, LP150Q, GRAIL420A, and GRAIL660B were used for investigation of lunar gravity model selection effect. OD results were assessed by position and velocity uncertainties with error covariance and an external orbit comparison using simulated true orbit. The effect of the lunar gravity models on the long-term OD, degree and order level, measurement-acquisition condition, and lunar altitude was investigated. For efficiency verification, computational times for the five lunar gravity models were compared. Results showed that significant improvements to OD accuracy are observed by applying a GRAIL-based model; however, applying a full order and degree gravity modeling is not always the best strategy, owing to the computational burden. Consequently, we consider that OD using GRAIL660B with 70 × 70 degree and order is the most efficient strategy for mission preanalysis. This study provides useful guideline for KPLO OD analysis during nominal mission operation.

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Baginski, Frank, Kaiyu Zhao, Joshua Furer, Justin Landay, Shantanu Bailoor, Peter Gorham, Gary Varner, et al. "Shape Analysis and Deployment of the ExaVolt Antenna." Journal of Astronomical Instrumentation 06, no. 02 (May 11, 2017): 1740004. http://dx.doi.org/10.1142/s2251171717400049.

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The ExaVolt Antenna (EVA) is the next generation balloon-borne ultra-high energy (UHE) particle observatory under development for NASA’s suborbital super-pressure balloon program in Antarctica. Unlike a typical mission where the balloon lifts a gondola that carries the primary scientific instrument, the EVA mission is a first-of-its-kind in that the balloon itself is part of the science instrument. Specifically, a toroidal RF reflector is mounted onto the outside surface of a superpressure balloon (SPB) and a feed antenna is suspended inside the balloon, creating a high-gain antenna system with a synoptic view of the Antarctic ice sheet. The EVA mission presents a number of technical challenges. For example, can a stowed feed antenna be inserted through an opening in the top-plate? Can the feed antenna be deployed during the ascent? Once float altitude is achieved, how might small shape changes in the balloon shape affect the antenna performance over the life of the EVA mission? The EVA team utilized a combination of testing with a 1/20-scale physical model, mathematical modeling and numerical simulations to probe these and related questions. While the problems are challenging, they are solvable with current technology and expertise. Experiments with a 1/20-scale EVA physical model outline a pathway for inserting a stowed feed into a SPB. Analysis indicates the EVA system will ascend, deploy and assume a stable configuration at float altitude. Nominal shape changes in an Antarctic SPB are sufficiently small to allow the use of the surface of the balloon as a high-gain reflector.

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Gopi, Dattatreya, A. R. G. Chandra, K. Mouli, V. Janardhan Reddy, G. K. Chaitanya, and S. Ramu. "Miniaturized cpw-fed conformal antenna for guided missiles." Journal of Physics: Conference Series 1706 (December 2020): 012073. http://dx.doi.org/10.1088/1742-6596/1706/1/012073.

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Schuss, J. J., J. Upton, B. Myers, T. Sikina, A. Rohwer, P. Makridakas, R. Francois, L. Wardle, and R. Smith. "The IRIDIUM main mission antenna concept." IEEE Transactions on Antennas and Propagation 47, no. 3 (March 1999): 416–24. http://dx.doi.org/10.1109/8.768775.

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Hechler, F., and W. M. Folkner. "Mission analysis for the Laser Interferometer Space Antenna (LISA) mission." Advances in Space Research 32, no. 7 (October 2003): 1277–82. http://dx.doi.org/10.1016/s0273-1177(03)90332-2.

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Nahas, M. M., and M. Nahas. "Bandwidth and Efficiency Enhancement of Rectangular Patch Antenna for SHF Applications." Engineering, Technology & Applied Science Research 9, no. 6 (December 1, 2019): 4962–67. http://dx.doi.org/10.48084/etasr.3014.

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The microstrip patch antenna is used in various communication applications including cellular phones, satellites, missiles, and radars, due to its several attractive features such as small size and weight, low cost, and easy fabrication. The microstrip patch antenna consists of a top radiating patch, a bottom ground plane, and a dielectric substrate in between. The patch can have different shapes, the rectangular patch being the most commonly used. In practice, the microstrip antenna suffers from narrow bandwidth and low gain efficiency. This paper aims to enhance the bandwidth and efficiency of a rectangular-patch antenna using the High-Frequency Structure Simulator (HFSS). Initially different patch sizes and substrate materials are investigated and optimal antenna parameters are achieved. Then, the antenna performance is further enhanced by inserting single and double slot designs into the patch. Two cost-effective feeding methods are involved in the investigation. The antenna is designed to operate in the Super High Frequency (SHF) band.

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Sanchez, Victor, Fernando Martin, Aingeru Barrio, Iñaki Pinto, Rafael Garcia, Manuel Sierra, Leandro de Haro, José Luis Besada, and Belén Galocha. "Measurement of BepiColombo mission medium gain antenna parameters under realistic thermal conditions." International Journal of Microwave and Wireless Technologies 9, no. 7 (September 2017): 1409–18. http://dx.doi.org/10.1017/s175907871700099x.

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This paper is focused on explaining the radiation test in temperature performed on the Engineering and Qualification Model of the Medium Gain Antenna Radiofrequency (MGA-RFA) Assembly of ESA's BepiColombo mission. The goal of this program is to observe and study Mercury and its surroundings in a very demanding environment in terms of temperature and radiation. The MGA is an X-band two-axis steerable horn, which provides bidirectional communications between spacecraft and Earth as backup of the High Gain Antenna and also operates as primary communication link at several mission stages or conditions. The paper presents the measurement set-up for the qualification campaign of the antenna, where it was necessary to characterize the antenna in a representative thermal environment, and the results obtained from this test. Results of test up to 150°C show how gain and radiation pattern shapes are slightly affected by thermal stress, but without jeopardizing mission requirements. In addition, by analyzing correlation of this test with RF analysis in the same thermal conditions, it becomes possible to accurately extrapolate the MGA-RFA behavior up to temperatures of more than 500°C. This fact allowed the successful space qualification of this model.

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Li, Cun L., Xiao W. Shi, Hai H. Wang, and Xin Li. "A compact missile-borne conformal array antenna with off-axis radiation." Microwave and Optical Technology Letters 60, no. 4 (March 8, 2018): 1010–13. http://dx.doi.org/10.1002/mop.31094.

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Kuzmin, L. S., and A. V. Chiginev. "TWO-FREQUENCY CROSS-SLOT ANTENNA WITH RESONANT COLD ELECTRON BOLOMETERS FOR APPLICATION IN CORE SPACE MISSION." Devices and Methods of Measurements 8, no. 2 (June 9, 2017): 101–7. http://dx.doi.org/10.21122/2220-9506-2017-8-2-101-107.

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Measurements of the CMB properties is an actual problem of modern astronomy. The aim of the present paper is the numerical modeling of the two-frequency planar cross-slot antenna designed for operation in the receiving system of the orbital telescope Cosmic Origins Explorer (COrE), developed by the European Space Agency to measure the CMB.The proposed antenna is a planar metal layer on the dielectric substrate, and comprising a set of four slots intersecting each other at right angles. The composition also includes a set of microstrip lines for transmitting a signal from the resonant slots to cold-electron bolometers, and a lens for forming the main beam of the radiation diagram. Calculation of the antenna system is made by electrodynamic modeling software package CST Microwave Studio. As a result of the modeling, the radiation diagram of the antenna in two frequency channels as well as its frequency characteristics are obtained.The calculation gives the following characteristics of the receiving system on the basis of cross-slot antenna: width of the main beam of the radiation diagram – 24.3° and 19.5°, the ellipticity of the beam – 4.2 % and 0.3 %, the bandwidth – 14.9 GHz and 19.0 GHz, polarization resolution – 23.4 dB and 29.6 dB, where the former value refers to the 75 GHz channel, and the latter refers to 105 GHz channel.It is proposed to use a cross-slot antenna in dual-frequency mode together with resonant cold-electron bolometers to work in the receiving system of the orbital telescope COrE. Comparison of the calculated antenna characteristics with the requirements set by the European Space Agency, have shown the possibility of using this type of antenna as part COrE mission.

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LOTT, DEREK A. "The species of Acylophorus Nordmann (Coleoptera: Staphylinidae: Staphylininae) in continental sub-Saharan Africa." Zootaxa 2402, no. 1 (March 18, 2010): 1. http://dx.doi.org/10.11646/zootaxa.2402.1.1.

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Types of Acylophorus delphinus Fauvel from Madagascar and Acylophorus species found in continental sub-Saharan Africa are revised. Lectotypes are designated for the following species: A. orientalis Fauvel, A. picipennis Bernhauer, A. densipennis Bernhauer, A. antennalis Cameron, A. tenuiceps Bernhauer, A. collarti Cameron, A. congoensis Cameron, A. mareei Bernhauer, A. trigonocephalus Cameron and A. grandis Bernhauer. Type material for A. rufipennis Cameron could not be located and the name is considered to be a nomen dubium. The following new synonymies are established: A. orientalis Fauvel = A. picipennis Bernhauer syn. n., = A. marginalis Cameron syn. n.; A. antennalis Cameron = A. tenuiceps Bernhauer syn. n.; A. trigonocephalus Cameron = A. lomaensis Bordoni syn. n. Seven new species are described: A. nitens sp. n. from Sudan, A. tshuapensis sp. n. from Congo, A. makhoreae sp. n. from Ethiopia, A. micans sp. n. from Côte d’Ivoire and Gabon, A. salifi sp. n. from Burkina Faso, A. minor sp. n. from Côte d’Ivoire and Nigeria, and A. setiger sp. n. from Bioko (Equatorial Guinea). A key is given to species groups defined by easily observed characters. Comparative diagnoses are given for species, their distributions mapped and their bionomics detailed where data are available. Forebodies, terminal segments of the maxillary palpi, antennae and aedeagi are figured for all species, except those represented by material with these parts missing. Mandibles and secondary sexual characters are figured for selected species.

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Miś, Tomasz Aleksander, and Józef Modelski. "The Analysis of Experimental Deployment of IGLUNA 2019 Trans-Ice Longwave System." Remote Sensing 12, no. 24 (December 10, 2020): 4045. http://dx.doi.org/10.3390/rs12244045.

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An experimental longwave system operating in the broadcasting spectrum with horizontal magnetic loop transmitting antennas is presented as an element of simulated lunar astronaut mission of the IGLUNA program of Swiss Space Center (ESA_Lab demonstrator) in June 2019 on the Klein Matterhorn glacier in Switzerland. The parameters of the antennas, the environment, the transmitter design, and propagation tests are presented. The best-suited propagation model is developed. As the system, using low powers, provided coverage of maximal distance of 2077.06 km, a single radio station of this type would cover about 36% of the Moon’s surface and allow in situ ground-penetrating research.

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Bao, Min, Peng Zhou, and Lin Shi. "Study on Deambiguity Algorithm for Double Antenna Forward Looking Missile Borne SAR." Journal of Electronics & Information Technology 35, no. 12 (February 23, 2014): 2857–62. http://dx.doi.org/10.3724/sp.j.1146.2013.00083.

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Liu, Wen-Chung, and Chih-Sheng Chen. "DESIGN OF MISSILE-MOUNTED SIW ANTENNA WITH HIGH DIRECTIVITY FOR DATA TRANSMISSION." Progress In Electromagnetics Research C 38 (2013): 79–88. http://dx.doi.org/10.2528/pierc13012910.

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Almradi, Ahmed M., and Sohail A. Dianat. "NDA SNR and CRLB Estimation Over MISO with STBC Channels." International Journal of Business Data Communications and Networking 8, no. 4 (October 2012): 1–16. http://dx.doi.org/10.4018/jbdcn.2012100101.

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This paper discusses the problem of Non Data Aided (NDA) Signal to Noise Ratio (SNR) estimation of Binary Phase Shift keying (BPSK) modulated signals using the Expectation Maximization (EM) Algorithm. In addition, the Cramer-Rao Lower Bounds (CRLB) for the estimation of Data Aided (DA) and Non Data Aided (NDA) Signal to Noise Ratio (SNR) estimation is derived. Multiple Input Single Output (MISO) channels with Space Time Block Codes (STBC) is used. The EM algorithm is a method that finds the Maximum Likelihood (ML) solution iteratively when there are unobserved (hidden or missing) data. Extension of the proposed approach to other types of linearly modulated signals in estimating SNR is straight forward. The performance of the estimator is assessed using the NDA CRLBs. Alamouti coding technique is used in this paper with two transmit antennas and one receive antenna. The authors’ assumption is that the received signal is corrupted by additive white Gaussian noise (AWGN) with unknown variance, and scaled by fixed unknown complex channel gain. Monte Carlo simulations are used to show that the proposed estimator offers a substantial improvement over the conventional Single Input Single Output (SISO) NDA SNR estimator due to the use of the statistical dependences in space and time. Moreover, the proposed NDA SNR estimator works close to the NDA SNR estimator over Single Input Multiple Output (SIMO) channels.

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Koubeissi, M., E. Arnaud, M. Thevenot, T. Monediere, E. Peragin, and H. Diez. "Wide aperture circularly polarized antenna for small telemetry satellites." International Journal of Microwave and Wireless Technologies 4, no. 6 (September 19, 2012): 623–28. http://dx.doi.org/10.1017/s1759078712000608.

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This paper focuses on the design of a telemetry antenna system intended for small satellites. It provides an axial ratio (AR) lower than 3 dB over ±60° conical space angle with over 20% of bandwidth. The antenna consists of a multilayer patch element fed by a wideband feeding circuit. The latter is an appropriate adjustment of 90° hybrid couplers and 180° ring coupler. We show that this design provides high-quality circular polarization properties for agile small satellites without having to suspend their mission to download their data and also without sacrificing the antenna low profile and wide bandwidth. The antenna is fabricated and the experimental performance is presented and followed by a discussion.

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Akanksha, K. "Accurate and Efficient Representation of Obstacles Using Radar Visualizer." International Journal for Research in Applied Science and Engineering Technology 9, no. VI (June 30, 2021): 4429–31. http://dx.doi.org/10.22214/ijraset.2021.36107.

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Radar is a detection system that uses radio waves to determine the range, angle or velocity of objects. It can be used to detect aircraft, ships, spacecraft, guided missiles, motor vehicles, weather formations, and terrain. A radar system consist of a transmitting antenna, a receiving antenna (often same antenna is used for transmitting and receiving) and a receiver and process to determine properties of the objects. In our project we are detecting the target position of the obstacles that come in our way be it in military, aircrafts, ships, clouds, etc. using MATLAB. Using MATLAB, you can: analyze data, develop algorithms, create models and applications. The language, apps, and build in math functions enable you to quickly explore multiple approaches to arrive at a solution. Using MATLAB and Simulink we are doing radar visualizer.

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Schuss, J. J., J. Upton, B. Myers, T. Sikina, A. Rohwer, P. Makridakas, R. Francois, L. Wardle, W. Kreutel, and R. Smith. "The IRIDIUM/sup R/ main mission antenna concept." IEEE Aerospace and Electronic Systems Magazine 12, no. 12 (1997): 3–12. http://dx.doi.org/10.1109/62.641860.

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Journal articles on the topic 'Missile Antennas'

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