Analysis of a parasitic-tuned microstrip antenna using the FDTD method

In this study the FDTD method has been utilized for analysis of parasitic-tuned microstrip antennas. The second-order dispersive boundary condition is efficient for satisfying the absorbing boundary condition. The parasitic-tuned microstrip antenna can give wider bandwidth and low return loss for proper size and location of parasitic elements. When the gap between the parasitic elements and the non-radiating edges is 2.5 times the substrate thickness, the antenna shows the best performance with respect to the values of bandwidth and return loss. The depolarization ratio is improved when a parasitic element is added at the radiating edge with a gap of 0.8 mm in this case.