微波功率SiC MESFET小信号等效电路建模研究

在传统GaAs MESFET器件小信号模型基础上提出一种更适合SiC MESFET器件的小信号等效电路模型.该模型在引入了与栅压相关的输入电导后,明显改善了S11的拟合精度.提出直接利用cold FET反向栅压偏置下的S参数,通过曲线拟合和外插技术提取SiC MESFET小信号等效电路寄生参数的方法.该模型应用于国内SiCMESFET工艺线,在O.5～18GHz范围内S参数的仿真值和实测值非常吻合.

Accurate Determining the Small-Signal Equivalent Circuit of SiC MESFET

A modified small signal equivalent circuit with gate voltage-varied conductance for SiC MESFET is proposed in this paper,and the fitted S11 is improved remarkably compared with conventional GaAs MESFET small signal equivalent circuit.A simple and accurate method based on full RF characteristic to directly determine the small-signal equivalent circuit of SiC MESFET is also proposed and validated.The model and method have been implemented in civil SiC MESFET processing line,and the determined equivalent circuit fits the S-parameters very well up to 18GHz.