A size-reduced, broadband, bidirectional, circularly polarized antenna for potential application in WLAN, WiMAX, 4G, and 5G frequency bands

A bidirectional, circularly polarized antenna with a miniaturized design and broadband capabilities is proposed for consideration in WLAN 2.4/3.65-GHz, WiMAX 2.3/2.5-GHz, 4G, and 5G frequency bands. The front side of the antenna consists of a hexagonal slot, a hexagonal patch, ten meander tips, and rectangular corner notches to achieve broad impedance and axial ratio bandwidth. The feedline on the backside of the antenna with accompanying shorting pin is offset to further increase the common bandwidth. Also, the four corners of the antenna substrate are removed to decrease the electrical size. The designed antenna is fabricated and measured to validate simulation results. From measured results the antenna has a −10-dB impedance bandwidth of 89.7% (1.60–4.20 GHz) and a 3-dB axial ratio bandwidth of 70.5% (1.80–3.76 GHz). The peak realized gain in the boresight direction is 3.65 dBi, which occurs at 1.88 GHz.