A Decade Bandwidth 90 W GaN HEMT Push-Pull Power Amplifier for VHF / UHF Applications

A decade bandwidth 90 W, GaN HEMT push-pull power amplifier has been demonstrated. The power amplifier exhibits 18 dB small-signal gain with 20-1100 MHz 3-dB bandwidth and obtains 82.2-107.5 W CW output power with 51.9-73.8 % drain efficiency and 15.2-16.3 dB power gain over the 100-1000 MHz band. The push-pull power amplifier occupies a 2 x 2 inch PCB area and uses a novel compact broadband low loss coaxial coiled 1:1 balun to combine two 45 W packaged broadband lossy matched GaN HEMT amplifiers matched to 25 U. The packaged amplifiers contain a GaN on SiC HEMT operating at 50 V drain voltage with integrated passive matching circuitry on GaAs substrate. These amplifiers are targeted for use in multi-band multi-standard communication systems and for instrumentation applications.