Patent ID: 10148009

Abstract:
A method and apparatus for phase-mode feeding a circular antenna array for beamsteering is provided. A Butler Matrix having M antenna-side ports and M input/output ports is coupled to beamsteering circuitry. The coupled input/output ports may include a port corresponding to a phase-mode having an order magnitude greater than one. The coupled input/output ports may include ports of three different order magnitudes of phase-mode. The Butler Matrix is coupled to M inner ports of a radial waveguide, and the antenna elements are coupled to N outer ports of the waveguide, where N>M. Where M=4, the input/output ports correspond to a zeroth order phase-mode, plus and minus 1st order phase-modes, and a second order phase-mode. The zeroth order phase-mode may be used for beamsteering closer to the radial axis of the antenna array while the second order phase-mode may be used for beamsteering further from the radial axis.