K-band spatial combiner using active array modules in an oversized rectangular waveguide

The spatial power combining technique provides a viable solution to the realization of solid-state power sources and amplifiers at microwave and mm-wave frequencies. The technique integrates a large number of amplifiers to provide large output power with higher efficiency that cannot be realized with circuit level combining. In particular, the tray structure and the waveguide environment of the system provides the broadband characteristic and good thermal management.; A k-band combining system was built in an oversized waveguide environment. The system contains antenna trays and amplifiers, built monolithically using flip-chip bonding for the active devices. The waveguide environment operates in the dominant TE10 mode with TE20 mode being sufficiently suppressed. Each antenna is then essentially a waveguide-finline-CPW transformer that couples energy from the waveguide mode to a power device. This dissertation includes the practical design of power amplifiers at 18GHz using PHEMT devices, a passive combiner using antenna arrays, and the power combiner modules. Some combiner characteristics such as the phase noise reduction, graceful degradation are also included.