This paper presents a high-efficiency Ka-band solid-state power combining amplifier on the basis of a novel waveguide magic tee. By employing 16 low-power amplifier modules and compact waveguide power combining network with a low loss microstrip-to-waveguide transition, the output loss of the combining circuit is minimized, so a high combining efficiency larger than 85% from 34 to 36 GHz is obtained. Modular architecture is adopted in the combiner design. The single amplifier, bias circuit and heat sink are all fabricated separately, which add great flexibility to the system. Modular amplifiers can be premade and reserved in case any malfunctioning amplifier needs to be replaced. In addition, the improved power combining amplifier has the advantages of low loss, high isolation, compact structure, excellent heat-sink, etc.
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