Applying CFDTD (conformal finite difference time domain) method to analyzing microstrip patch antenna with complicated patch shape

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.