Polarization-Reconfigurable Single-Port Patch Antenna with Switchable Horizontal and Vertical Modes for Mid-Band 5G Applications

With the growing demand for compact, high-performance and reconfigurable antenna systems in mid-band 5G communication (3.3–6 GHz), polarization agility has become essential for improving link reliability and spectral efficiency. This paper presents the design, simulation and experimental validation of a polarization reconfigurable microstrip patch antenna capable of dynamically switching between vertical (VP) and horizontal (HP) linear polarization states using a single RF excitation port. The antenna employs two orthogonal microstrip feedlines connected via PIN diode switches to a common feed, enabling selective excitation of adjacent patch edges. This facilitates activation of the fundamental TM01​ or TM10​ mode, producing vertical or horizontal polarization, respectively. Fabricated on an FR4 substrate, the antenna features a low-profile, planar configuration ideal for compact RF systems. Simulated and measured resonances occur at 5.31/5.40 GHz (VP) and 5.27/5.33 GHz (HP), respectively. The antenna achieves –10 dB impedance bandwidths of 3.52% (VP) and 6.01% (HP), peak gains of 2.48 dBi and 2.76 dBi and axial ratios above 48 dB, confirming high polarization purity and low cross-polarization. Radiation patterns show good agreement with simulations. The proposed design offers a compact and efficient solution for applications demanding polarization reconfigurability, making it well-suited for advanced wireless communication systems.