InP HBT millimeter-wave power amplifier implemented using planar radial power combiner

In this paper a millimeter-wave power amplifier implemented using a planar radial type power splitter and combiner is presented. The amplifier achieves an unsaturated output power of 23 dBm at 71 GHz with a corresponding P1dB of 20.8 dBm. The radial layout for the combiner allows 4 unit amplifiers to be combined in a single stage of power combining with a compact layout. The amplifier is implemented using an InP HBT process with ft/fmax values of 300/300 GHz.