Microwave Beam Steering for Radar Antennas Through the Use of Waveguide Mode Mixing

The present invention relates to a method of, and corresponding apparatus for, electronically steering an antenna beam. Beam steering is accomplished by altering the electric-field distribution at the open-end of one or more overmoded waveguides through the controlled mixing of multiple modes. An example method includes propagating a signal in multiple modes in a waveguide, and controlling the relative phase and amplitude of the respective modes, relative to each other, to steer the beam. A further example includes a common waveguide enabling the propagation of multiple modes, first and second waveguides enabling the propagation of respective first and second modes, a splitter/combiner coupling the first and second waveguides to the common waveguide, and a controller for controlling a propagation characteristic of the modes relative to each other in a least one path to steer the beam. Electronically steering a beam is useful for fine-tuned angle adjustments and tight beam scanning.