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 similar to 31 GHz, and the corresponding power combining efficiency is more than 80%. The obtained output power is more than 25 W in 30 similar to 30.6 GHz.