Exploring Design Guidelines of AlGaN/GaN Gated-Anode Diodes Toward High-Power, High-Efficiency Microwave Rectification

Gated-anode diodes (GADs) based on gallium nitride (GaN) high-electron-mobility transistors (HEMTs) present considerable potential for high-power microwave rectification. To identify the structural challenges that limit rectification efficiency, GADs must be evaluated at the circuit level using a high-accuracy SPICE model. In our previous study, we proposed a GAD model incorporating a large-signal HEMT model. In this study, we refined the GAD model to enable simulation at higher input power and to reproduce current collapse. We also developed, for the first time, a 5.8-GHz watt-class rectifier monolithic microwave integrated circuit (MMIC) for model verification. The refined model reproduced the measured circuit characteristics and clarified the power-loss mechanism within GADs. However, the model deviated from the measurements at high input power, likely due to increased leakage current caused by self-heating. These results highlight the need to consider self-heating in device design and to optimize the turn-on voltage (${V}_{\text {on}}\text {)}$according to the target input power.