A Wideband Slot-Ring Phased Array Antenna With Switchable Polarization for 5G NR

The escalating demand for advanced communication systems necessitates the development of wideband phased array antennas. In particular, achieving wideband performance in polarization-reconfigurable phased array antennas is gaining popularity in aerospace, remote sensing, and smart city applications due to their ability to mitigate polarization mismatches, enhance data rates, and reduce multipath fading losses. However, the previously-reported polarization-reconfigurable phased arrays have limited modularity, bandwidth, and require complex feeding networks. To address these limitations, this paper presents a wideband slot-ring phased array antenna with switchable polarization for 5G NR (n77, n78, and n79) bands. This antenna is designed using the Characteristic Mode Analysis in HFSS. It is observed that incorporating meandered lines in the narrow strip ground plane and in the square patch helps to significantly improve the bandwidth performance of the antenna. To achieve reconfigurable polarization, a 2×2 array has been designed with half wavelength element spacing at the center frequency. The operating frequency ranges from 3.3 to 5 GHz, achieving a 40% fractional bandwidth across all polarization modes. It achieves polarization agility by dynamically switching between horizontal, vertical, LHCP, and RHCP states through simple phase adjustments. In circular polarization mode, the axial ratio bandwidth matches the impedance bandwidth, making it ideal for V2X communication and 5G MIMO base stations. In addition, this array maintains a uniform radiation pattern throughout the entire operating frequency and supports beam steering up to ±30° in quad polarization mode, with a radiation efficiency of 95%. To validate the scalability, a 4×4 array is designed, confirming that the concept can be extended to larger arrays for high-capacity, high-gain applications in next-generation wireless networks. Measurement data presented in this paper validate the efficacy of the proposed concept, with experimental results exhibiting close agreement with simulations. Given its wideband operation, high radiation efficiency, polarization reconfigurability, beam-steering capabilities, and ease of fabrication and assembly, the proposed antenna is well-suited for 5G MIMO networks, satellite communications, and future wireless systems that require dynamic polarization control.