A Wideband Dual-Polarized Omnidirectional Antenna for 5G/WLAN

A compact wideband dual-polarized omnidirectional antenna with good isolation for the fifth generation/wireless local area networks communication is presented in this paper. The dual-polarized characteristic of the proposed antenna is achieved by combining a vertical polarization (VP) monopole antenna and horizontal polarization (HP) cross bow-tie antenna, which is excited by a <inline-formula> <tex-math notation="LaTeX">$50~\Omega $ </tex-math></inline-formula> Sub-Miniature-A (SMA) connector and a broadband feeding network, respectively. The size of the proposed antenna is only <inline-formula> <tex-math notation="LaTeX">$0.38\lambda \times 0.38\lambda \times 0.27\lambda $ </tex-math></inline-formula> (with <inline-formula> <tex-math notation="LaTeX">$\lambda $ </tex-math></inline-formula> being the wavelength of the lowest frequency). The simulated isolation of the proposed dual-polarized omnidirectional antenna is below −38dB in the bandwidth from 2.3 GHz to 3.7 GHz (about 46.7%, <inline-formula> <tex-math notation="LaTeX">$\vert S_{11}\vert < -10$ </tex-math></inline-formula> dB), taking no account of the commercial RF-Balun and SMA connectors. Moreover, the measured isolation of the proposed antenna with a feeding network is about −20 dB. The gain variations at the center frequency in the horizontal plane are 1.6 dB for VP element and 2.4 dB for HP element. And the lowest peak realized gains of the proposed cross bow-tie shaped antenna and the monopole antenna are about 4 dB and 2 dB, respectively. A prototype of the proposed dual-polarized omnidirectional antenna was fabricated to verify the simulated results, and the measured results are in a good agreement with the simulated ones.