Circularly polarized magneto-electric dipole antenna with microstrip line cross aperture-coupled excitation

• This paper proposes a novel Circularly Polarized MED (CP-MED) antenna with a pioneering cross-slot coupling feeding mechanism, designed to enhance polarization purity and impedance bandwidth for 5G and satellite applications. • The design integrates orthogonal steel conductor plates as electric and magnetic dipoles, excited via a microstrip line through a cross-slot, achieving a 90 ∘ phase difference for circular polarization. • The array achieves a 15.63% impedance bandwidth (2.89-3.38 GHz), transitioning from elliptical to circular polarization, with a peak Right-hand Circular Polarization (RHCP) gain of 5 dBic and a stable unidirectional radiation pattern with a half-power beamwidth of 66.32 ∘ . • Compared to state-of-the-art MED designs, this work offers a compact, low-profile solution with improved polarization diversity, making it suitable for integration into compact communication devices. • Challenges such as gain stability and manufacturing tolerances are addressed, paving the way for practical implementation in high-frequency systems. This paper introduces a compact Circularly Polarized Magneto-electric Dipole (CP-MED) antenna, excited via a single-feed microstrip line using a cross-slot aperture. The design achieves circular polarization through a geometrically controlled transition from linear to elliptical to circular polarization, facilitated by the balanced excitation of orthogonal electric and magnetic dipole plates. To ensure both cost-effectiveness and structural robustness, the antenna utilizes laser-cut steel radiating elements mounted above a single-layer FR4 substrate. The cross-slot feed is specifically engineered to generate two orthogonal modes with a 90 ∘ phase difference, eliminating the need for external phase-shifting networks or multilayer structures. A comprehensive equivalent circuit model has been developed by integrating lumped-element components with microstrip transmission-line theory, drawing on Schelkunoff’s dipole formulation and Babinet-Booker duality. This model offers valuable physical insights into the coupling mechanism, accurately capturing the interaction between electric and magnetic dipole resonances. Experimental results demonstrate a remarkable correlation with the simulations, showcasing an impedance bandwidth of 15.63% (ranging from 2.89 to 3.38 GHz) and a 3-dB Axial Ratio bandwidth of 6.2% (spanning 3.04 to 3.23 GHz). The CP-MED array achieves a peak realized gain of 5 dBic, exhibiting broadside radiation with a half-power beamwidth of 66.32 ∘ and more than 20 dB of Left-hand Circular Polarization suppression in the main direction ( θ = 0 ∘ and ϕ = 0 ∘ ), confirming strong polarization purity. Due to its compact design, single-layer structure, and strong circular polarization characteristics, the proposed antenna is well-suited for sub-6-GHz wireless and satellite communication systems that require wide coverage, stable radiation patterns, and cost-effective implementation.