Compact, low-loss, micromachined rectangular coaxial millimeter-wave power combining networks

Compact air-dielectric rectangular coaxial power combiners are constructed using the PolyStrata process. Designs for 2-1 combiners centered at 60 GHz 94 GHz are presented, as well as a 4-1 combiner centered at 60 GHz. The simulated insertion loss across the bands of the 60 GHz and 94 GHz combiners is 0.11 dB and 0.1 dB, respectively. Both bands of the 2-1 combiner exhibit output isolation of greater than 14 dB. An implementation of a “direct” 4-1 combiner is presented; simulated insertion loss of less than 0.15 dB and output isolation of greater than 18 dB are also reported. Measured results of back-to-back combiners for all designs and frequencies discussed herein are presented. Good agreement with simulated results is shown.