A Single-Layer Compact Wideband Circularly Polarized Patch Array for 5G Communications

This letter presents a single-layer antenna array with wideband circular polarization. The array is formed by 2 x 2 element antennas, each element including two radiators mutually coupled to each other and fed by a sequential feeding network. The antenna array is designed, fabricated, and measured with overall size of 1.49? x 1.49? at the center frequency of 28 GHz. The proposed antenna achieves the desired radiation patterns and provides excellent characteristics, including a wide bandwidth (BW) and compact structure. The results show a large BW of 31.32% and a wide axial ratio of 20.2%, which is the largest found in the literature for similarly sized arrays on a single layer. Besides, the peak gain of 13.8 dBi is achieved over the operating frequency range. These merits confirm the proposed antenna design as a suitable choice for 5G communications.