对集中匹配电路加载天线的扩展FDTD场路协同计算

Analysis of a Lumped Matching Circuit Loaded Antenna Using an Extended FDTD-based Field-circuit Co-simulation Method

采用扩展时域有限差分(finite-difference time-domain,FDTD)算法实现电磁场和电路混合系统的协同计算。介绍了扩展FDTD的原理和嵌入不同集总元件的迭代公式,以一款馈电端口加载有集中匹配电路的微带双偶极子天线为例,采用扩展FDTD算法仿真了该天线和匹配电路混合系统。仿真中通过将微带馈线直接插入复数频率偏移完全匹配层(complex frequency shifted perfectly matched layer,CFS-PML),用2次FDTD运算提取了该混合系统的S11参数。对该加载天线进行了加工制作和实验测试,结果表明:基于扩展FDTD的场路协同计算和实验测试结果吻合良好,在加载集中匹配电路后,该微带偶极子天线的方向图和增益基本保持不变,谐振频率点发生偏移,S11曲线有显著变化。

The co-simulation of the electromagnetic-field-and-circuits hybrid system was studied by employing the extended finite-difference time-domain(FDTD) algorithm.The extended FDTD's principle and its iterative formula reflecting the embedment of lumped devices in the FDTD cells were introduced.As a sample,a microstrip double dipole antenna loaded with a lumped matching circuit at its input port,which was an antenna-and-circuit hybrid system,was simulated by the extended FDTD.In the simulation,S11 of this antenna was obtained by using a technique,which directly inserted the microstrip feeding line into a complex frequency shifted perfectly matched layer(CFS-PML) and executed the FDTD program twice.The loaded antenna was fabricated and measured.Results showed that the measurement agrees well with the simulation,and for the antenna,the lumped matching circuit slightly affects its gain and radiation patterns,but varies its resonant frequency and significantly changed its S11 curve.