共形时域有限差分法在不同形状微带贴片天线特性分析中的应用

应用共形时域有限差分法(CFDTD)对不同形状微带贴片天线的特性进行了有效的分析。为了提高计算精度,对天线激励源、导体贴片等组成部分进行了预处理。通过对时域结果的傅立叶变换,得到与频率有关的天线特性参数。实际制作并测试了五角形和椭圆形贴片微带天线的反射损耗和辐射场方向图,并与CFDTD仿真结果进行了比较。结果吻合良好,表明该方法对复杂微带天线的分析非常有效。

Applying CFDTD(Conformal Finite Difference Time Domain) Method to Analyzing Microstrip Patch Antenna with Complicated Patch Shape

Aim. Most theoretical papers on microstrip patch antenna have been concerned with rectangular or circular patch,but more complicated patches such as pentagon and ellipse have appeared in some important applications.We now apply CFDTD(conformal finite difference time domain) method to theoretically analyzing microstrip patch antenna whose patch shape is more complicated.Section 1 in the full paper introduces theoretical analysis.In subsection 1.1,we point out that eqs.(1) through(6),taken from Ref.4 authored by D.M.Sheen et al,are FDTD(finite difference time domain) formulas convenient for computer processing.Subsection 1.2 presents CFDTD formulas derived by us for treating the conductor portion of microstrip antenna;the formulas are three in number and eq.(8) in the full paper gives only CFDTD formula for the Hz component.Subsection 1.3 describes the treatment of excitation in order to acquire results in broad frequency range.Subsection 1.4 describes the treatment of absorbing boundary conditions.Subsection 1.5 explains how to transform data in time-domain into data in frequency-domain.Section 2 gives two simulation examples for testing accuracy of the above-mentioned theoretical methods.Subsections 2.1 and 2.2 deal with pentagonal patch antenna and elliptical one respectively.Return-loss simulation results are given in Fig.3(pentagonal patch) and Fig.6(elliptical patch).Radiation pattern simulation results are given in Fig.4(pentagonal patch) and Fig.7(elliptical patch). Theoretical analysis in section 1 and simulated results in section 2 show that the method is an efficient tool for modeling complicated microstrip structure.