Microstrip Patch Antenna Simulation Using FDTD Method with Code Implementation

This document describes the simulation of microstrip patch antennas using the Finite-Difference Time-Domain (FDTD) method. The FDTD algorithm works by discretizing Maxwell's equations in both time and space domains, using central difference approximations for derivative calculations. Key implementation steps include setting up the Yee grid for electromagnetic field components, defining material properties, and implementing absorbing boundary conditions like PML (Perfectly Matched Layer) to simulate open space radiation. The simulation typically involves updating electric and magnetic fields alternately using leapfrog time-stepping scheme, where E-field updates depend on previous H-field values and material properties, while H-field updates rely on previous E-field values. For microstrip patch antenna simulation, special attention must be paid to substrate dielectric modeling, feed point implementation, and far-field pattern calculation through near-field to far-field transformation algorithms. The code structure generally includes initialization of field arrays, time-loop implementation with field updates, and post-processing for antenna parameters like return loss, radiation patterns, and gain calculations.