GaN-based Power Amplifier MMIC and Module for D-Band Applications

This paper presents GaN-based power amplifier integrated circuits targeting D-band frequencies. Two chips have been realized, using transistors with a gate length of 100 nm and 70 nm. On-wafer S-Parameter measurements of the designed GaN MMICs yields a high linear-gain of more than 20 dB and 25 dB at 130 GHz, respectively. Performed large-signal measurements of assembled samples demonstrated a saturated output power of 21.9 dBm (150 mW) for the 100 nm MMIC, along with a maximum PAE of 8.8 % at 140 GHz. Assembled 70 nm MMICs yield an improved large-signal performance of 23.1 dBm (200 mW) and more than 11.2 % PAE. Based on the power amplifier integrated circuits with the longer gate-length, a compact split-block module with waveguide flanges has been fabricated. The assembled module has been characterized between 130-150 GHz, demonstrating a typical linear-gain of 19 dB (+/- 3 dB within the frequency band), along with more than 18 dBm (60 mW).