High-efficiency magnetoelectric dipole antenna array with passive beam-switching for 5G applications

Abstract

This paper presents a 2D scanning array of magneto-electric (ME) dipole antennas designed for 5G millimeter-wave applications. The design features a Butler matrix comprising four hybrid couplers, realized as a printed ridge gap waveguide (PRGW) matrix, thereby achieving a phase error within ±6° across the 27–33 GHz frequency range. Through the integration of this Butler matrix with a beam-switching network (BSN) that feeds a 2 × 2 ME dipole array, four distinct beams are generated in specified directions. A substrate-integrated waveguide (SIW) layer with four bends serves as the interconnect, efficiently feeding the antenna elements without degrading their performance. A prototype of the proposed antenna was fabricated and experimentally validated. Measurements demonstrate an impedance bandwidth exceeding 33% (—10 dB return loss) at 30 GHz (covering 25-35 GHz), side-lobe levels below —15 dB, and a peak gain of approximately 14.5 ± 0.9 dB within the matching bandwidth. Moreover, the passive BSN achieves a radiation efficiency above 90% across the 27-33 GHz range. The proposed antenna exhibits high efficiency, stable radiation patterns, and consistently high gain. The compact PRGW-based Butler matrix provides a practical and effective solution for designing millimeter-wave antennas for next-generation 5G systems.