A millimeter-wave solid-state power combining circuit based on low-loss corporate waveguide structure

In this paper, we present a Ka-band (30 GHz-35 GHz) solid-state power combining circuit using 4 low-power amplifier modules. By using low-loss waveguide power dividing/combining network and a monolithic microwave integrated circuit (MMIC) with a low-loss microstrip-to-waveguide transition, the combining circuit output loss is minimized, so a high combining efficiency larger than 85% from 30 GHz to 35 GHz is achieved. Measured results show a good agreement with simulated results. Meanwhile the new combing structure shows many advantages, such as easy assembling and maintenance, excellent heat-sink capacity, a strong potential for higher power and higher frequency. Modular architecture is adopted in the combiner design, adding great flexibility to circuit operation. Modular amplifiers can be premade and reserved in case any malfunctioning amplifier needs to be replaced.