共查询到20条相似文献,搜索用时 187 毫秒
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基于场耦合的概念,建立了有源相控阵天线阵面的机电耦合模型。天线阵面的阵元布置为环栅阵,仿真计算了阵面因子方向图和阵面方向图。依据此环栅阵,将结构误差加入机电耦合模型,得到结构变形误差,阵面加工误差,累积安装误差对天线阵面电性能的影响数据。研究分析结构误差对天线增益、栅瓣电平、波束指向和波束宽度等天线阵面电性能指标的影响,可知天线阵面对振动的位移响应对电性能的影响满足系统的指标要求,阵面加工误差和累积安装误差对天线阵面电性能的影响较小。 相似文献
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雷达天线实时变形测试系统 总被引:1,自引:0,他引:1
提出了通过加速度传感器来建立雷达天线阵面工作变形的实时测量系统,该系统避免了激光测量法中基准不稳定影响测试精度,和采用位移传感器直接测量无法消除基础位移等问题,并通过试验测试验证了频域数字积分的精度,解决了测试数据通过高频汇流环进行数据实时传输等问题,为实时把握天线阵面变形对电性能的影响和改进天线阵面的结构设计提供了科学依据。 相似文献
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分形天线是分形几何和天线技术交叉的产物,分形概念用于天线阵的工程合成,有助于将等幅度面阵和随机面阵的优点结合起来,将分形的自相似特征用于随机面阵设计有助于控制旁瓣区域的天线方向图。基于维尔斯特拉斯(Weierstrass)广义函数,研究天线阵排列系数函数的连续和不可微分的特性,通过对天线阵的分形电动力学和天线阵可实现性条件的研究分析,给出天线阵合成示例,得到Weierstrass不同尺寸天线阵的辐射特性与分形因子的作用关系。指出雷达天线阵列在结构、频带、副瓣等方面需要进行改进。 相似文献
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Mutual coupling compensation in small array antennas 总被引:10,自引:0,他引:10
A technique to compensate for mutual coupling in a small array is developed and experimentally verified. Mathematically, the compensation consists of a matrix multiplication performed on the received-signal vector. This, in effect, restores the signals as received by the isolated elements in the absence of mutual coupling. This technique is most practical for digital beamforming antennas where the matrix operation can be readily implemented 相似文献
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Eshrah I.A. Kishk A.A. Yakovlev A.B. Glisson A.W. 《Antennas and Propagation, IEEE Transactions on》2006,54(5):1433-1441
A simple equivalent circuit is used to model an arbitrarily loaded waveguide probe with emphasis on probe-excited dielectric resonator antennas. The values of the lumped inductance and capacitance are obtained via the method of moments analysis for the problem of a short-circuited probe acting as a waveguide scatterer. For problems involving the excitation of an external load, the aperture through which the probe extends to the load is modeled by a shunt capacitance, and an additional transformer is introduced to model the coupling to the load. Expressions for these circuit parameters are obtained using curve-fitting techniques and are employed to determine the lengths and positions of an array of waveguide probes used to feed external loads with feeding currents of desired relative values. The procedure is applied to synthesize waveguide-fed antenna arrays to achieve a specified radiation pattern. The scanning capabilities and the effect of the mutual coupling are studied by comparing radiation patterns obtained from the analysis of the whole array and from the pattern multiplication principle. 相似文献
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Cherrette A.R. Acosta R.J. Lam P.T. Lee S.-W. 《Antennas and Propagation, IEEE Transactions on》1989,37(8):966-978
Various aspects of reflector surface distortion compensation are explored by first assuming the reflector distortion is given and then designing the compensating feed array. The sensitivity of boresight directivity to changing surface distortion parameters for fixed feed-array geometries is examined. It is found that feed array compensation is feasible only for distortions with low spatial frequency content, such as those distortions induced by thermal and gravitational effects. The optimum directivity methods for determining element excitation is found to yield slightly better values of directivity than those for the conjugate field matching (CMF) technique. However, the CFM technique has, in general, much lower sidelobe levels and lends itself to simple realization in hardware. In view of these results, distortion compensation using an array feed is concluded to be a reasonable approach to improving antenna performance for large, space-based reflector antennas that are not easily accessible for tuning and have time-dependent surface distortions 相似文献
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Interstitial arrays of insulated antennas have shown promise for microwave hyperthermia treatment of deep-seated tumors. Available analytical techniques for predicting the electromagnetic (EM) power deposition of these antennas have been limited to the case of a homogeneous conductive medium surrounding the array. Since tumors and host tissue may differ in their electrical characteristics, it is necessary to consider the impact of this variation in electrical properties and the geometry of the tumor in the calculation of the EM field distribution and power deposition pattern when modeling interstitial antennas. In this paper a three-dimensional model of a tumor of arbitrary shape subjected to the fields of an interstitial antenna array is developed to predict the EM power deposition in an inhomogeneous tumor-tissue medium. The volume integral equation for the imbedded tumor is developed and solved by method of moments. The incident fields are calculated based on the available formulation of interstitial antennas in homogeneous media. The accuracy of the developed computer code was checked by comparing the results from the volume integral approach with the Mie solution for the special case of spherical tumors. Good comparison was obtained for tumors with properties approximately 25 percent different from those of the surrounding tissue. Comparisons of results from models of antenna arrays with and without imbedded tumors show significant differences in their predictions of the EM power deposition in the tumor. Hyperthermia protocols generally specify uniform temperature distribution within the tumor. The developed inhomogeneous model was used to examine the feasibility of controlling the uniformity of the power deposition pattern in large tumors by adjusting the amplitude or relative phase between the array elements. Results are presented to show that a phase lead of +90 degrees or relative amplitude of 4.0 on one antenna in a square array of four antennas could be used to shift the power deposition pattern to sequentially heat outer portions of a 2 cm diameter tumor, thereby achieving a more uniform time-averaged temperature distribution in the tumor. 相似文献