A Multi-Mode Superposition Technique for Circular Polarized Beamforming and Steering in Mobile Communication and Radar Systems

Focusing electromagnetic energy into a narrow sliver of space (beamforming) and directing this energy to desired areas (beam steering), which have been conventionally achieved using phased array antennas, allow for mitigating the propagation loss of energy and are critical for emerging communication and radar systems. This work presents a novel beamforming and steering technique which is based on the superposition of circular waveguide transverse electric (TEn1) modes. In this technique, a plurality of superposed omnidirectional circular polarized (CP) TEn1 waves, where each wave has a specific azimuthal radiation phase profile, is created. The unique phase profile of each wave is leveraged for CP beamforming and 360° beam steering. The proposed beamforming and steering approach can be realized using a single antenna structure with a relatively small dimension. It can be integrated into user mobile equipment, vehicles, base stations, repeaters, and radars, and due to its CP radiation, would be more immune to multipath fading and multiple reflections. It can also eliminate the requirement of a precise alignment for transmitting and receiving antennas. A CP beamformer antenna performing based on the proposed method is designed and fabricated for operation within 26.5-29.5 GHz which covers n257 and n261 bands for 5G systems. The test results verify the functionality of the proposed CP beamforming and steering technique. This technique can also be adapted for high-resolution automotive radars by employing a rotating antenna, and preliminary simulation and measurement results are also presented.