25 W solid state power combining amplifier in Ka-band

This paper presents a new waveguide-based spatial power combining amplifier at millimeter-wave frequency.In this amplifier,a waveguide-microstrip spatial power dividing/combining network is adopted.A four-way broadband low loss symmetrical power dividing/combining is achieved at millimeter-wave frequency with an easy manufacture processing and convenience of integrating solid-state high power devices.The measured output power of this amplifier is more than 43.4 dBm in 29～31 GHz,and the corresponding power combining efficiency is more than 80%.The obtained output power is more than 25 W in 30～30.6 GHz.