Multi-Mode Antennas for Ultra-Wide-Angle Scanning Millimeter-Wave Arrays

In this paper, a novel multi-mode millimeter-wave antenna array with enhanced scan range and reduced scan losses is presented. The individual array element consists of a differentially fed microstrip patch on top of which a cylindrical dielectric resonator is integrated. The radiation pattern of the antenna element can be reconfigured by changing the phase offset between the feeding ports of the patch and the dielectric resonator to excite two distinct radiating modes. With such a feature, the field of view can be divided into two different subspaces, with the first one covering the angular range from -75to 0and the second one from 0to +75. In a 1 × 16 linear array configuration, the achieved scan range extends from -75to 75along the horizontal plane with a maximal gain loss of 3 dB, which is better than the ideal cos θ0 behavior. The proposed design operates in the frequency range between 27 GHz and 29.5 GHz and, thanks to its wide-scan capabilities, constitutes an effective solution for upcoming 5G/6G millimeter-wave wireless communications.