Design of an airline coax radial power combiner with enhanced isolation

An X-band radial power combiner based on an airline coax with 0.15 dB measured insertion loss, 8 dB minimum port-to-port isolation, 33% bandwidth, and the ability to handle kilowatt power levels is presented in this work. The design can readily be scaled to arbitrary frequencies or any number of ports. The methods used to select the parameters and optimize the design are presented. The models are validated by a 9-port X-band proof-of-concept combiner.