Dual-Band Circularly Polarized Antenna Array for 5G Millimeter-Wave Applications

A dual-band miniaturized e-shaped antenna with circular polarization (CP) at 28 and 38 GHz is presented in this work for 5G millimeter-wave applications. Characteristic mode analysis (CMA) is used in the design steps of the antenna. This compact antenna consists of a main radiating patch surrounded by an L-shaped and hat-shaped metallic strips. The design was implemented on a single RO5880 substrate with a thickness of 0.508 mm, and fed by a single coaxial cable. A 2 x 2 antenna array was also developed and validated. The dimensions of this array were 1.5 lambda(0) x 1.86 lambda(0) (where lambda(0) is the free space wavelength at 28 GHz). In the lower band of 28 GHz, 95% total efficiency and 12.69 dBiC gain were obtained, while in the higher band of 38 GHz, 90% total efficiency and 11.10 dBiC gain were achieved. The beamforming capability of this dual band array was investigated as well.