背腔式分形微带贴片天线电磁散射特性分析

Analysis of electromagnetic scattering by microstrip fractal patch antennas residing in a cavity

将矢量有限元方法和边界积分方法相结合 ,分析背腔式分形微带贴片天线的电磁散射特性 .给出了该方法的理论模型 .根据变分原理得出原有问题的等效泛函 ,将背腔体用四面体单元进行剖分 ,采用矢量基函数展开各单元内的电场 ,按照里兹方法得到一组线性方程 ,再利用腔体开口面上电磁场的连续性 ,应用边界积分方程得到另外一组线性方程 ,两组方程构成完备的线性方程组 ,由此求出腔体开口面的等效磁流和原问题的散射场 .通过将该混合方法应用于传统的背腔式微带贴片天线的RCS计算 ,验证了该方法的正确性 .在此基础上 ,对背腔式分形微带贴片天线的电磁散射特性进行了计算和分析 .结果显示 。

A hybrid technique (FEM/BI) is employed for the evaluation of electromagnetic scattering by microstrip fractal patch antennas residing in a cavity. In accordance with the variational theory, the equivalent functional of the problem is given. Edge-based FEM and boundary integral equation are employed to deduce the complete matrix equation for the calculation of the equivalent magnetic current on the opening of the cavity, from which RCS (radar cross section) of the antennas are computed. Numerical results for a conventional microstrip patch antenna are presented to demonstrate the accuracy of the technique. Then, a number of numerical results for microstrip fractal patch antennas residing in a cavity are presented. The calculated results show that the electromagnetic scattering of the microstrip fractal patch antennas residing in a cavity depends mainly on the driven element rather than the parasitic fractal elements.