A Novel Millimeter-Wave Single-Fed Circularly Polarized ME-Dipole Antenna With Self-Decoupling Capability and Wide-Angle Scanning Performance

Abstract

In the design of circularly polarized (CP) antenna phased arrays, achieving wide-angle scanning while maintaining high polarization purity remains a key challenge. This letter presents a novel millimeter-wave (mm-wave), single-fed CP magneto-electric dipole (ME-dipole) antenna. By asymmetrically arranging the magnetic dipole vias and incorporating a chamfered structure in the planar electric dipole, the proposed single-fed antenna not only achieves a wide 3 dB axial ratio (AR) beamwidth exceeding 183°, but also exhibits an inherent self-decoupling characteristic, providing high port isolation of 42 dB. Furthermore, in the array configuration, the design effectively exploits coupled near-field to broaden the beamwidth of the active element pattern (AEP). A 1 × 8 phased array prototype has been fabricated and tested. The results demonstrate a ±67° beam scanning capability at 26.3 GHz, with AR maintained below 3 dB across the entire scan range, and a gain variation of no more than 2.8 dB. Notably, this performance is achieved without requiring any supplementary decoupling or beam-broadening components, enabling a compact and low-complexity design.