Phase Response of Scattered Fields from Microstrip Reflectarray Elements Using FDTD Method

摘要

In this paper, the scattering of incident plane wave onto a microstrip infinite array consisting of similar microstrip patch elements is investigated. The Finite Difference Time Domain (FDTD) method is employed to calculate the phase shifts. At first, the infinite array configuration is converted into an equivalent unit cell configuration containing only one radiator element using PEC and PMC walls around it. Then, a Gaussian TEM plane wave excitation is introduced for this equivalent waveguide structure and the reflected field phase shifts are determined by discretizing the time domain Maxwell's equations and applying the FDTD method. By using discrete time Fourier transforms, the phase response is obtained in the frequency domain. The phase response versus the microstrip patch size is determined by using available relations for patch resonance dimensions. This method is applied to several elements such as microstrip square patch, microstrip dipole and double concentric microstrip rings. The results are compared with HFSS software results and some reported results in the literature.