Continuous Full-Azimuth Beam Steering using Mode Synchronization in Dual-Mode Circular Waveguides

Abstract

A new concept for beam steering using a dual-mode circular waveguide is proposed. Two antennas are designed using this concept to achieve full-azimuth beam steering over a narrow bandwidth. The idea is to use the first two non-degenerate circular waveguide modes (TE11 and TM01) and synchronize them to achieve a desired interference pattern on the waveguide cross section. Slots are then introduced into the waveguide to allow radiation along the azimuthal direction where the two modes add constructively. Using an orthomode transducer, the polarization of the TE11 mode is rotated, by modulating the amplitude of the two signals at each port, to achieve full-azimuth beam steering. This technique is therefore fundamentally different from the traditional methods of beam steering that use mechanical control or phase control.