In this study, a low-loss and compact planar power combiner for solid state power amplifiers (SSPAs) is proposed. It combines eight power amplifier modules with low insertion loss (IL) and high reliability by utilising a novel magic-Tee configuration and E-plane bend along with a suitable microstrip-to-waveguide transition. The fabricated prototype was implemented through automatic milling machines to produce three planar layers that form the final structure. This novel approach enabled precise fabrication, simple assembly of the SSPAs as well as low-cost manufacturing in comparison with existing traditional approaches. This process is suitable for SSPAs operating from 4 to 40 GHz. The combined IL of the implemented combiner network is less than 0.6 dB at Ka-band, 0.5 dB at Ku-band, and 0.4 dB at X-band while exhibiting a 10% fractional bandwidth.
IET Microwaves, Antennas and Propagation

Gholami, M. (Mehrdad), Amaya, R, & Yagoub, M.C.E. (Mustapha C.E.). (2016). Low-loss compact power combiner for solid state power amplifiers with high reliability. IET Microwaves, Antennas and Propagation, 10(3), 310–317. doi:10.1049/iet-map.2015.0403