High‐efficiency broadband power amplifier design via ideal de‐embedding and direct compensation of GaN‐HEMTs parasitics

In this work, a design approach for broadband high‐efficiency power amplifiers is presented. The proposed technique is based on deductive de‐embedding of the nonlinear parasitics of packaged GaN‐HEMT devices. A new transistor parasitics equivalent network is proposed that utilises a model‐based extraction flow. A simple two‐element compensation network is then used to accurately compensate the extracted nonlinear device parasitics; this enables optimum load resistance to be presented to the device current generator using a real‐to‐real matching network. In order to validate the proposed concept, a single‐ended Class‐AB power amplifier is designed and fabricated using a Wolfspeed 25‐W GaN HEMT ‘CGH40025F’ transistor. At a centre frequency of 2.35 GHz, a fractional bandwidth of 55% is achieved. The measured average drain efficiency and power gain of the designed power amplifier are 71% and 10.4 dB, respectively.