FDTD分析包含S参数器件模型的微波有源电路

将有源器件的S参数引入到FDTD迭代中,传统方法采用了逆傅立叶变换和复杂的卷积技术.为了避免繁琐的卷积运算,本文首先把测量的S参数转化为Y参数,采用Vector Fitting技术拟合得到Y参数的s域有理多项式,然后通过差分技术或者Z变换技术将Y参数引入到FDTD运算中.另外,为了提高该方法的计算效率及稳定性,利用FDTD方法提取分布元件部分的时域特征模型(TDCM),再结合本文方法全波分析微波有源电路,达到了更好的效果.最后,作为例子模拟了一个微波FET放大器电路,验证了本文方法的有效性和精度.

FDTD Analysis on Microwave Active Circuits with Lumped Device Characterized by S-parameters

Inverse Fourier transforms and complex convolution integral are adopted in traditional method to take S pa- rameters of active components into FDTD iteration steps. To avoid the complex convolution integral calculation, we firstly transform the measured S parameters into Y parameters, and then the Vector Fitting technique is used to obtain rational poly- nomial of Y parameters in s domain. Through difference technique or Z-transform method, the Y parameter is taken into FDTD iteration steps. To increase the computational efficiency and stability, FDTD is used to distill the time domain charac- ter model of distributing elements. An example of microwave FET amplifier circuit is analyzed, and validates the efficiency and precision of the method.