Study on transmission characteristic of the PRDGS with different dielectric constants

Periodic rectangle defected ground structure (PRDGS) is a class of frequency selective surfaces (FSS) and it can be widely applied in microwave circuits in order to obtain high performance circuits. The influence on transmission characteristic of PRDGS is calculated by the finite difference time domain method (FDTD) when the PRDGS has the different dielectric constants and the different rectangle unit sizes. The center frequency of stopband can be minimized and the width of stopband and the deepness of stopband are kept constant when the dielectric constants increase and the rectangle unit sizes remain constant. The width of stopband and the deepness of stopband can increase and the center frequency of stopband remains constant with increasing the rectangle unit sizes when the dielectric constants are kept constant. The results obtained through using the FDTD reach an excellent agreement with the ones using the equivalent circuit model method about the center frequency of stopband, and the mean relative calculation error doesn´t exceed 1.72%. The helpful conclusion given in the paper can be served as a powerful tool to analyze and design the PRDGS.