Multiband and Dual-Polarized Omnidirectional Antenna for 2G/3G/LTE Application

Abstract

A novel multiband and vertically/horizontally polarized omnidirectional antenna is proposed for 2G/3G/LTE mobile communication systems. The proposed antenna is a combination of a modified asymmetric biconical for vertical polarization (VP) and six printed dipoles with concentric placement for horizontal polarization (HP). The VP element consists of two modified cones with different diameters, designed to work in the multiband GSM+3G/4G. Printed dipoles of the HP element are fed by a six-way power splitter printed on the substrate. The HP element is nested between two cones of the VP element, forming a compact structure. The bottom cone can be used as the reflector for VP and HP in the overlapping work frequencies band for 3G and LTE communication systems. The VP element achieves a bandwidth of 17.4% and gain of 1.5 dBi in the 806 ~ 960-MHz band. The HP element achieves a bandwidth of 35% (1880 ~ 2700 MHz) directly overlapping with the VP-element higher frequency band. An isolation of 25 dB is achieved in the overlapping band. The cross-polarization levels in the azimuth plane for both VP and HP are lower than -15 dB.