A Compact Gate-Width Scalable Model for Dual-Gate GaAs pHEMT

A compact gate-width scalable model of dual-gate gallium arsenide pseudo high electron mobility transistors (GaAs pHEMTs) is proposed. We derive the model based on analytical formulation and represent it with a simplified circuit containing only eight elements. Compared with the dual-gate model using two separate devices, this modeling method is much simpler in characterization and can extract intrinsic parameters directly from two-port measurements. Extrinsic parameters are extracted by de-embedding method evolved from the conventional open-short method. Devices with different gate widths and numbers of finger are modeled to verify the scaling effect. The simulated results based on the proposed model agree with the measured results well up to 40 GHz for
$0.25~\mu \text{m}$
GaAs pHEMT devices. In addition, a large-signal model is built based on the proposed dual-gate model. A 2 GHz power amplifier was realized to illustrate the suitability of the proposed model for circuit design.