An X-band tray-type spatial power combiner using uniplanar quasi-Yagi antennas

There has been a surge in research into a variety of spatial power combining techniques of solid-state devices. The driving force behind this activity has been a growing demand for reliable high power solid-state sources for applications at upper microwave and millimeter-wave frequencies. In order to achieve power combining in space, active planar arrays, arranged in either tile or tray configuration, can be used. We focus on the tray-type amplifying spatial power combiner. Due to the use of end-fire-type antennas, the tray configuration offers an increased operational bandwidth and more space for the inclusion of active devices in comparison with its tile counterpart. Our investigations concern the active structure of an X-band spatial power combiner consisting of seven trays of planar quasi-Yagi antennas (Deal, W.R. et al., IEEE Trans. Microwave Theory Tech., vol.48, no.6, p.910-18, 2000) connected back-to-back with active stages in between. Hard horns, for signal launching and receiving, and Schiffman phase shifters within the trays are used to provide uniform field magnitude and phase across the trays to achieve the large dynamic range of the combiner. Performance comparison of the power combining structure with and without phase compensation is presented.