X band highly efficient GaN power amplifier utilizing built-in electroformed heat sinks for advanced thermal management

We report an X-band class-E GaN power amplifier with built-in electroformed heat sink. Our novel approach for packaging, cooling and interconnecting allows “known good die” GaN MMICs to be combined with other components (Si, SiGe, passives etc) and enable GaN based RF front-ends. The presented amplifier offers continuous wave (CW) output power (P out ) of 34 dBm (power density of 3.2W/mm) with associated power added efficiency (PAE) of 72% and drain efficiency (DE) of 82% when biased at 15V. At 21V the PA offers CW P out of 36.4 dBm (power density of 5.5W/mm) and associated PAE of 57%. Compared to identical PAs mounted on Cu-W heat sinks with silver epoxy and AuSn eutectic solder this corresponds to a 2x and 1.5x improvement in P out respectively.