An Improved InP HEMT Small Signal Model with RC Network In this paper, an improved smallsignal model of an InAlAsInGaAs InPbased HEMT device based on RC network is proposed. In the smallsignal model, the gatedrain resistance R gd  is added to characterize the symmetrical distribution of the undergate depletion region in the lowvoltage case. The RsubCsub series network is used to characterize the influence of lossy substrate on the output characteristics of InP HEMT and improve the fitting accuracy of output admittance. The extraction of extrinsic parameters is realized by the openshort test structure method. The intrinsic elements are determined by solving the intrinsic Y parameters and making reasonable optimizations. The results show that the measurement data of Sparameters are consistent with the simulation results of the model, and the RsubCsub series network can significantly improve the fitting accuracy of output admittance.

Scalable Modeling for the CPW Gap Discontinuity at Frequency up to 150 GHz The coplanar waveguide (CPW) gap discontinuity is an important component of many applications in the monolithic microwave integrated circuits (MMICs). Therefore, accurate modeling of the CPW gap discontinuity is very important and fundamental for the design of MMICs. In this work, a new lumped equiva1entcircuit model which can accurately describe the characterization of the CPW gap discontinuity from 0 to 150 GHz is proposed. The parameters are extracted from electromagnetic (EM) simulations simply and conveniently without any complicated optimization algorithms. And we make the model scalable in gap length, width and space. Satisfactory fitting accuracy is obtained between the model data and EM simulations, which verifies that our model can be implemented in computeraided design software to reduce design time and save computer resources.