功率GaAs MESFET小信号等效电路模型的参数求解

Parameter extraction of the power GaAs MESFET small-signal equivalent circuit

采用非本征元件的参数作为本征元件参数函数的自变量的方法 ,求解金属肖特基势垒场效应晶体管小信号等效电路模型 ,并采用相对误差来构建目标函数 .以场效应晶体管在零偏置状态的非本征元件值作为初值 ,通过优化求得了热场效应晶体管状态的本征元件值 .该方法具有收敛快 ,精度高和效率高的优点 ,便于移植到微波器件计算机辅助设计和模拟软件中 .

Intrinsic parameters are extracted from functions of MESFET's intrinsic elements by using extrinsic parameters as independent variables. We have proposed that relative errors for intrinsic elements are used to define objective functions. Extrinsic elements' values of FET's in an unbiased state are used as the starting point of the independent variables. Then intrinsic elements' values for hot FET's are extracted by the optimization method. The calculated and measured results are in good agreement. The relative errors of S-parameters are 0.09% for S11, 1.1% for S12, 0.08% for S21, and 2.26% for S22 respectively. This method has advantages of fast convergence, high precision and efficiency. It is easy to transplant into microwave CAD tools for device design and simulation, and is more reasonable, as well as great of practical engineering significance.