The potential performance of wide bandgap microwave power MESFETs

This paper investigates the theoretical potential of the wide bandgap (WBG) semiconductors silicon carbide and gallium nitride for microwave power MESFET devices. Their expected performances are compared to a baseline model of the current GaAs capability. In contrast to previous studies, the impedance matching and associated stability issues arising when deploying the devices in a microwave power amplifier are examined. For a given gate width and channel current, it is determined that WBG device models predict gain within 1 dB of that of GaAs, an input impedance approaching a factor of two higher and an increase in output power of a factor of 6. Based on current GaAs performance at 10 GHz, a conservative first-principles analysis suggests that WBG microwave integrated circuits will provide ∼80 W output power and modules will provide ∼400 W output power.