Spatial Power Combiner Using Cavity Modes in W-Band

In this paper, we report on a new 6-way MMIC power combiner amplifier utilizing cavity modes. The combiner is designed around a square cavity operating in the TM320 electromagnetic mode. Such a configuration produces a total of 6 lobes of maximum field intensity inside the cavity. By placing probes (attached to MMIC amplifier chips) in alignment with the points of maximum field strength, a highly compact power combiner can be achieved. We illustrate this concept using a set of 1 Watt W-band GaN MMIC chips, placed in layered copper sheets and oriented so the MMICs line up with the regions of maximum field strength. A 6-way power combiner was built and was able to deliver 5.5 Watts of output power and 13.4% PAE using a miniature package.