共查询到16条相似文献,搜索用时 140 毫秒
1.
2.
大型反射面天线由于比较庞大、容易受外力的影响发生形变,因此计算表面具有形变反射面天线的方向图就变得尤为重要。反射面表面发生形变后,对辐射积分的处理会变得比较复杂,文中利用表面雅可比变换,对辐射积分进行处理,使得辐射积分的数学表示变得相对简单,将计算结果与GRASP仿真结果作了对比,结果基本一致,验证了方法的正确性。 相似文献
3.
4.
5.
6.
7.
8.
9.
将超表面结构作为天线的辐射单元,可以降低天线剖面,拓展其带宽,并改善其辐射性能。特征模分析的方法可以用来揭示超表面天线的小型化机理并提供设计思路。基于此方法,设计了3个小型化的超表面天线,并进行了仿真验证。3个超表面天线的辐射单元尺寸分别减小到0.53λ0×0.51λ0,0.50λ0×0.49λ0和0.35λ0×0.29λ0,与4×4方形贴片单元构成的超表面天线相比,尺寸均缩减了20%以上,实现了超表面天线的小型化。 相似文献
10.
针对天线雷达截面减缩问题,该文提出一种基于二极管控制的可重构频率选择表面结构,并将其用于天线的雷达截面减缩技术。论文将可重构技术应用于频率选择表面设计,使得频率选择表面可以在带通型以及带阻型之间进行相互切换。为了在保证天线辐射特性的前提下降低天线的雷达截面,该文考虑将可重构频率选择表面作为天线反射板用以置换一般的金属反射板。通过二极管导通/截断使得可重构频率选择表面反射板处于不同状态,以实现天线在不同工作状态下的RCS减缩控制及切换。仿真及实测结果表明,使用可重构频率选择表面反射板,天线雷达截面的最大减缩量可达20 dB以上,减缩角域可达-60+60,同时天线的辐射特性几乎未发生变化。该方法可在保证天线辐射特性的基础上极大程度降低天线的雷达截面,并能做到天线雷达截面减缩频段的可重构。 相似文献
11.
12.
The physical optics/aperture integration (PO/AI) formulation is often used to analyze the radiation patterns of reflector antennas. In this study, the PO/AI radiation integrals for distorted reflector antennas are addressed. The surface error of the antennas is approximated by a series of surface expansion functions. The radiation integral is decomposed into a series of radiation-type integrals, each of which corresponds to one of the surface expansion functions. Each of these radiation-type integrals is then weighted by amplitude coefficients. The advantage of performing the decomposition is that each of the radiation-type integrals can be computed and the pattern data stored. The computation of the pattern for a distorted reflector antenna with a changing error profile is performed by recalling the pattern data for each perturbation term and weighting it with the amplitude coefficient. This facilitates rapid evaluation of the radiation integral in cases where the error profile is changing (for example, time-varying errors). The superposition of integrals presented in this paper was shown to be valid for surface-error profiles up to 0.1 λ rms amplitude 相似文献
13.
N. P. Yeliseyeva 《Journal of Communications Technology and Electronics》2008,53(7):731-746
The method of the uniform geometric theory of diffraction (UGTD) was used to solve a 3D diffraction problem of the radiation of an electric dipole arbitrarily positioned inside a 90° reflector with finite dimensions. For three mutually orthogonal orientations of a half-wave dipole, space radiation-power patterns are calculated and the field structure is analyzed. The influence of diffraction effects at the reflector edges on the field intensity in the direction of the maximum of the dipole’s radiation field and the dipole’s radiation resistance is studied as a function of the dipole position relative to the reflector sides. 相似文献
14.
利用电磁场分析软件FEKO,研究了抛物面天线在破片穿孔时天线方向图的变化规律。通过对物理光学法(PO)和物理绕射理论(PTD)的混合使用,对战损后抛物面天线的电气性能进行了建模与分析,以比较反射面损坏前后对天线方向图的影响。着重研究了天线反射面毁伤后,毁伤孔数、孔径及其位置变化对方向图的影响。 相似文献
15.
A dual-frequency Cassegrain reflector antenna has been investigated in which the secondary mirror is constructed from a stack of waveguides. The secondary mirror behaves as a highpass filter, giving access to the prime-focus feed position at the higher-frequency band. The copolar and crosspolar radiation patterns are discussed. 相似文献
16.
The development and application of a numerical technique for the rapid calculation of the far-field radiation patterns of a reflector antenna from either a measured or computed feed pattern are reported. The reflector is defined by the intersection of a cone with any surface of revolution or an offset sector of any surface of revolution. The feed is assumed to be linearly polarized and can have an arbitrary location. Both the copolarized and the cross polarized reflector radiation patterns are computed. Calculations using the technique compare closely with measured radiation patterns of a waveguide-fed offset parabolic reflector. The unique features of this technique are the freedom from restrictive feed assumptions and the numerical methods used in preparing the aperture plane electric field data for integration. 相似文献