Narrowband amplifier with excellent power combining efficiency

Based on a coaxial waveguide power-dividing/combining circuit, a four-device solid-state power amplifier with excellent power combining efficiency is presented. The fabricated power amplifier combining four monolithic microwave integrated circuit power amplifiers shows a 13-16.65 dB small-signal gain over a wide bandwidth of 7-13.5 GHz. The measured maximum output power at 1 dB compression is 25.4 dBm at 11 GHz, with a power-combining efficiency of 91%.