An Octave Bandwidth Spatial Power Combiner with Supply Voltage Control

This paper presents an analysis of an octave-bandwidth spatial power combiner, focusing on maintaining EIRP and efficiency across the band. Four GaN amplifier MMICs are fed with a broadband microstrip Wilkinson divider and power combine upon radiation from ridged-waveguide dielectric-loaded small-aperture horn antennas. The array is designed for operation from 6–12 GHz with 2-W PAs, with scalable element power and number of elements. As the supply voltage is varied on the individual PAs, the efficiency, power and linearity of the combiner present tradeoffs that are studied with CW and QAM-64 50-Mbaud modulated signals input to the combiner. Sidelobe level control with supply variation is also investigated and shows that it is possible to reduce sidelobes without significantly degrading EIRP.