Broadband circularly polarized magneto-electric dipole antenna for millimeter-wave communication

This article proposes a broadband circularly polarized (CP) magnetoelectric (ME) dipole antenna for millimeter-wave (mmW) communications. Based on a conventional linearly polarized ME-dipole, a pair of centrally symmetric L-shaped strips generates a rotating electric field with a 90° phase difference for CP radiation. A microstrip line feeds the antenna via a center-symmetrical matching branch on a coupling slot. A parasitic top layer enhances bandwidth, achieving 26.9% impedance bandwidth (|S₁₁| < -10 dB), 20.8% 3-dB axial ratio (AR) bandwidth, and 8 dBic peak gain for the element. A fabricated 4 × 4 array using these elements with sequential rotation technique (SRT) feeding shows good agreement between simulation and measurement: 30.7% impedance bandwidth, 26.5% 3-dB AR bandwidth, and 15 dBic peak gain. The design offers superior CP performance, low profile, and high integration for millimeter-wave systems.