A wideband circularly polarized magneto-electric dipole antenna with asymmetric geometries and parasitic elements for 5 G applications

• Innovative CP MED Design : A compact CP MED antenna with asymmetric L-shaped dipole arms and G-shaped parasitic elements achieves circular polarization for 5G n77/n78 bands (3.3–4.2 GHz) using a low-profile, aperture-coupled microstrip feed. • Broad Bandwidth Capability : Measured impedance bandwidth of 43.62% (2.85–4.44 GHz) and axial ratio bandwidth of 15.26% (3.39–3.95 GHz) ensure coverage of n78 and partial coverage of n77 bands. • Superior CP Performance : Delivers a peak RHCP gain of 7.46 dBic at 3.5 GHz with an RHCP-LHCP gain difference over 22 dB, confirming high circular polarization purity. • Cost-Effective Fabrication : Fabricated with Rogers RO4003 substrates using standard PCB techniques, offering simplicity and reduced cost compared to complex CP MED antennas with metallic reflectors. • Robust Radiation Characteristics : Exhibits unidirectional patterns with a 65.43° half-power beamwidth and >15 dB RHCP-LHCP difference at 3.5 GHz, ideal for 5G applications. • Competitive Performance : Comparison with state-of-the-art CP MED antennas ( Table 1 ) shows superior bandwidth and gain with a simpler, cost-effective printed structure, outperforming complex designs with metallic reflectors or vias. This paper introduces an innovative circularly polarized (CP) magneto-electric dipole (MED) antenna specifically designed for the core n77/n78 bands of 5G systems. The antenna features a low-profile, printed design with microstrip line aperture-coupled excitation. It utilizes asymmetric L-shaped electric dipole arms along with G-shaped parasitic elements on four Rogers RO4003 substrates to achieve CP through orthogonal electric field components that have a 90° phase difference and equal amplitudes. A systematic five-step design methodology is presented in this study that progressively reduces the axial ratio (AR) from 60 dB to below 3 dB by incorporating asymmetry and parasitic elements. The fabricated prototype, constructed using standard PCB techniques, demonstrates a measured impedance bandwidth (IBW) of 43.62% (2.85–4.44 GHz) and an AR bandwidth (ARBW) of 15.26% (3.39–3.95 GHz), effectively covering the n78 band and partially covering n77. The antenna achieves a peak right-hand circular polarization (RHCP) gain of 7.46 dBic at 3.5 GHz, with an RHCP-LHCP gain difference exceeding 22 dB and a half-power beamwidth of 65.43°. Measurements confirm stable unidirectional radiation patterns and high CP purity. In comparison to the best current CP MED antennas, the proposed design stands out due to its reduced fabrication complexity and compact size (0.762 × 0.762 × 0.191 λ₀³ at 3.5 GHz), offering a cost-effective, high-performance solution for 5G base station and mobile terminal applications.