共查询到20条相似文献,搜索用时 31 毫秒
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针对毫米波被动成像应用,设计了工作频率为84 ~ 94 GHz的16阵元焦平面阵列天线.聚焦天线采用500 mm口径的旋转抛物面以获得0.47°角分辨率;16馈源排成4×4阵列,相邻列馈源在垂直方向交错排列,使天线在垂直方向采样波束密度增加一倍,满足Nyquist采样要求;采用电流分布法并利用MATLAB编程计算馈源偏焦时天线辐射场分布,对馈源阵列排列参数进行优化设计.成像实验结果表明,天线沿水平方向扫描一次即可获得场景成像二维完全采样数据,成像耗时比传统扫描采样方式减少一倍. 相似文献
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Ming-Yi Li Kai Chang 《Antennas and Propagation, IEEE Transactions on》1999,47(3):453-457
This paper presents novel low-cost beam-steering techniques using microstrip patch antenna arrays fed by dielectric image lines (DILs). Two approaches are designed and used. The first, DILs without reflector plate, are used for feeding microstrip patch antenna arrays. Antenna array radiation beams are scanned when the operating frequency sweeps. The second, a dielectric image line with a movable reflector plate (DILWRP), is developed. The beam direction of the antenna array is controlled and steered by changing the perturbation distance between DIL and movable reflector plate at a given operating frequency. Both types of patch antenna array structures are simple, low cost, easily fabricated, stable, and reliable. Eight-element patch antenna arrays fed by DIL and DILWRP have been designed, fabricated, and tested. Experiments show good performance and results. Measurement results of scanning angles agree well with theoretical predictions 相似文献
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A phase-steered linear array feed for a parabolic cylindrical reflector antenna is considered. The nearly cylindrical wave radiated from this line feed in the Fresnel zone is expressed in terms of the isolated-element pattern. The correction to this wave due to diffraction from the endpoints of the line feed and from the grating formed by the array elements is also derived. 相似文献
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Davis R.M. Cha C.-C. Kamak S.G. Sadigh A. 《Antennas and Propagation, IEEE Transactions on》1991,39(3):391-400
An architecture for a scanning reflector antenna that supports wide-angle scanning, multioctave tunable bandwidths, transmit and receive operation, and monopulse processing is presented. It consists of a parabolic dish with an offset phased array. The array is actually a feed-through lens fed from a small feed array in the back of the lens. Beam steering is accomplished by using the feed array to illuminate clusters of elements within the lens that correspond to far-field beam positions. The evolution of the architecture and a computer model is described. Simulated and measured performance results are reported. Off-axis scanning of 10° to 15° appears to be possible while still supporting gain magnifications of four to five 相似文献
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Subreflectarrays for Reflector Surface Distortion Compensation 总被引:1,自引:0,他引:1
《Antennas and Propagation, IEEE Transactions on》2009,57(2):364-372
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《Electromagnetic Compatibility, IEEE Transactions on》1965,7(4):368-374
The radiating mechanisms of a reflector antenna system are discussed. Means of computing the various component fields are given, including aperture radiation, direct feed radiation, and diffracted radiation. An offset parabolic reflector antenna system fed with a corrugated horn is treated as an example. Means of reduction of the undesired components of radiation are suggested. 相似文献
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传声器系统指向性的实现主要有两种途径:一是通过特殊的声结构,二是通过传声器阵列。比较了一个带有抛物面形状反射面的传声器系统和与抛物面开口面积相同的圆形传声器阵列的差异。分别使用Kirchhoff-Helmholtz积分方程和阵列理论对这两种传声器系统的性能进行研究。数值模拟的结果表明,抛物面反射式传声器系统在高频时具有更高的灵敏度,其指向性通常也好于圆形传声器阵列。 相似文献
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Dau-Chyrh Chang Chang-Nan Hu Chia-I Hung Ko-Tai Ho 《Antennas and Propagation, IEEE Transactions on》1994,42(2):240-245
The performance degradation of an offset reflector antenna with off-axis scanning feed and distorted reflector surface can be improved by using a phased array feed. Generally, both analog attenuators and phase shifters are used in phased array feed. Yet, it seems to make the feed system very complicated. In this paper, a phase-only gradient search (POGS) algorithm is developed to optimize the performance of offset reflector antenna systems using phased array feed that is equipped with phase shifters only. This technique not only can greatly simplify the complexity of phased array feed, but also can provide the reflector antenna with better antenna gain and sidelobe level control capability. Simulation and experimental results are presented to illustrate the excellent performance of offset reflector, with limited beam scanning capability, can be obtained by using this less complicated phased array feed 相似文献
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A systematic and efficient two-dimensional method is presented for calculation of the three-dimensional radiation field from current sources which are located in proximity to long cylindrical scatterers. The method is applied to the calculation of the isolated-element pattern of a linear array of crossed dipoles (i.e., current sources) mounted above a long and narrow ground plane. Computed and measured results are given. The results are subsequently applied to the problem of prediction of the radiation characteristics of a cylindrical reflector antenna fed by such a linear array. 相似文献
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Space-borne satellite applications provide a vast array of services extending from global connectivity to Earth observation systems. The soil moisture radiation mission is a proposed space-borne passive microwave system complementary to the existing Earth observing system operating at low microwave frequencies and requiring an antenna with multibeam, high-beam efficiency, and dual polarization capabilities. To achieve both the large reflector size and the multibeam pattern at the operational frequencies an innovative multibeam reflector antenna design was needed. The advances in inflatable antenna technology has been proposed to overcome the launch vehicle size and weight restrictions. This paper describes a novel offset parabolic torus reflector antenna design that produces the desired multibeam pattern and is compatible with the inflatable antenna technology. Using the system requirements of this mission as an example, the design process for an inflatable parabolic torus reflector antenna is outlined, the development of suitable distortion models is given, and representative RF characteristics are presented. These RF characteristics include far-field patterns, beam contour patterns, beam efficiency, and other key performance parameters. The development of an advanced analytical modeling/numerical tool in support of the design effort is also detailed 相似文献
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The crosspolarisation efficiency of a reflector antenna is the ratio between the peak crosspolarisation from the complete antenna to that from the feed. The results of a parametric study into this factor for parabolic reflectors fed by a mathematical model of a common class of feeds are presented, and it is concluded that the efficiency is typically ?4 to ?6 dB. 相似文献
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Microwave antennas are extensively used in communications systems such as satellite, television and high-speed data transmission due to their wide and absolute bandwidth. Among the variety of microwave antennas, satellite communication commonly adopts an antenna of parabolic dish type, despite some drawbacks. In a primary fed design, there is considerable aperture blockage. An offset parabolic antenna design, which then eliminates the blockage, is susceptible to physical damage as its feed is significantly exposed from the body of reflector. The radial line slot array (RLSA) type antenna is thus designed to cope with the problems encountered in parabolic antennas. RLSA is a planar antenna suitable for direct broadcast satellite (DBS) reception, with advantages including high radiation efficiency (high gain), low profile, low cost and feed rear-mounted. The prototype development started with the selection of the cavity's dielectric material and construction of the feeding structure of coaxial-to-waveguide transition. Within the frequency band of interest, between 10.95 and 11.7?GHz, results, is showed a lower than ?10?dB of return loss. A DBS receiver test-bed had been developed to test the constructed antenna prototypes and it revealed that the prototype has the capability of receiving TV programs from DBS. 相似文献
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Presents measured results at 31-38 GHz of the radiation characteristics of a 0.252 m diameter parabolic dish fed at the prime focus by a short backfire antenna. The feed consists of an experimentally optimised design of a short backfire antenna, having a conical main reflector of 15° slant angle. The measured radiation patterns of the reflector system generally agree quite well with the prediction based on aperture field integration 相似文献
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This paper presents a new approach to beamforming in hybrid antennas. Using a scattering matrix model for the hybrid antenna system, a bidirectional transformation is developed that relates the signals at the hybrid system feed to the signals that would be present in a planar array at the location of the reflector aperture. For example, the received fields at the feed of a hybrid antenna system may be transformed into the fields at the reflector aperture, and these reflector aperture fields may then be processed as if they were received by a planar or linear array. Similarly, the desired field or current distribution across the reflector aperture when transmitting may be transformed into the required field or current distribution at the hybrid system feed. This method allows standard linear or planar array analysis and synthesis techniques to be used with the hybrid system. Examples are provided for transmit and receive weight synthesis. 相似文献
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在卫星星座跟踪、远距离微波能传输等需要构建大功率均匀场的领域,都需要具有平顶波束的高增益反射面天线.受多模和混合模喇叭天线的启发,文中创新性地在反射面天线设计中引入了多模的理念.首先提出了双模反射面的思路,即在标准抛物面天线的最大辐射方向上引入相位差为180°的反相模式场,由两种模式合成平顶波束.然后,将双模的理念推广... 相似文献
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Wen-Jen Tseng Chun-Shu Hu Shyh-Jong Chung 《Electronics letters》1998,34(14):1374-1376
An X-band planar reflector with a broad responding beam was developed using the Van Atta retrodirective antenna array. The reflector contained four antenna sub-arrays, each with six dual-slot antennas appropriately fed and paired by microstrip lines on the backside of the substrate. Good agreement has been achieved between theoretical and measured results 相似文献