Bandwidth Enhancement of a Broadband Dual-Polarized Antenna for 2G/3G/4G and IMT Base Stations

The bandwidth (BW) of a broadband dual-polarized antenna is enhanced for 2G/3G/4G systems and international mobile telecommunications services. The broadband dual-polarized element is a four-leaf clover antenna. By introducing a U-shaped slot to each leaf of the four-leaf clover and a parasitic element of four disks above the dual-polarized element, the BW enhancement is achieved. It is shown by simulation and experiment that the BW enhanced dual-polarized antenna achieves a BW of 67% (1.39-2.8 GHz) for reflection coefficients <;-15 dB with an isolation (ISO) of 30 dB. An eight-element antenna array is developed for base station applications. The antenna array has a BW of about 70% (1.32-2.74 GHz) with an ISO of 25 dB. The antenna array achieves an average gain of ~17 dBi and a half-power beamwidth of 65 ± 5°, suitable for base station applications.