Broadband Polarization Diversity Base Station Antenna for 3G Communication System

Antennas with dual linear slant polarization over a wide band are necessary for modern personal communication base-station applications. A ±45° polarization diversity antenna element constructed by novel umbrella-shaped dipoles is presented in this paper. The antenna has a half-power beam width of 63° ± 5° in the horizontal plane by designing a reflector over a bandwidth of 1710 to 2170 MHz, which covers not only 3G frequency band (1920–2170 MHz) but also DCS band (1710–1880 MHz) and PCS band (1850–1990 MHz). In addition the worst-case isolation between polarizations is 30 dB and the front-to-back ratio is more than 30 dB over the above frequency band.