采用CN-FDTD研究不同介电常数对PRDGS传输特性的影响

Study on the Influence on Transmission Characteristic of PRDGS with Different Dielectric Constants Based on CN-FDTD

周期性矩形缺陷接地结构(PRDGS)广泛应用于微波电路中以改善电路性能。采用无条件稳定的CrankNicolson格式FDTD(CN-FDTD)计算了介电常数和矩形单元尺寸对PRDGS传输特性的影响,在矩形单元尺寸一定时,随介电常数增大,PRDGS的阻带中心频率发生左移,而其宽度和深度保持不变;在介电常数一定时,随矩形尺寸增大,PRDGS的阻带宽度和深度会增大,其中心频率基本不变。比较两种方式计算的阻带中心频率,平均相对误差不超过1.72%,当CN-FDTD时间步长远大于CFL时,计算效率可提高77.2%,对PRDGS的分析设计有一定指导。

Periodic rectangle defected ground structure(PRDGS)can be widely applied in microwave circuits in order to obtain high performance circuits.The influence on transmission characteristic of PRDGS is calculated when the PRDGS has the different dielectric constants and the different rectangle unit sizes by the Crank-Nicolson FDTD(CN-FDTD),which is an unconditionally stable scheme.The center frequency of stopband can be minimized and the width of stopband and the deepness of stopband are kept constant when the dielectric constant 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 constant is kept constant.The results using two kinds of method to calculate the center frequency of stopband,and the mean relative calculation error doesn’t exceed 1.72%.When the CN-FDTD time step is larger than CFL,the computational efficiency can be improved by 77.2%.Therefore,helpful conclusion given in the paper can be served as a powerful tool to analyze and design the PRDGS.