Enhancing cross‐polarisation discrimination or axial ratio beamwidth of diagonally dual or circularly polarised base station antennas by using vertical parasitic elements

Abstract

The cross-polarisation discrimination (XPD) of a ± 45° dual-polarised base station antenna is enhanced by adding vertical parasitic elements. First, it is established that high XPD can be achieved by employing four vertical parasitic elements between a simple ± 45° dual-polarised radiator and ground. Second, based on the proposed method, a simple ± 45° dualpolarised antenna for a long-term evolution 1.71-2.17 GHz base station is designed, fabricated and measured. Compared with the antenna without vertical elements, XPDs are improved by about 7 dB in the horizontal plane due to the addition of the vertical parasitic elements. Third, with a wideband quadrature hybrid, the proposed antenna is shown to radiate circularly polarised waves. In particular, the 3 dB axial ratio beamwidth of the proposed antenna is increased from 84° to 195° with the addition of the four vertical parasitic elements.

Design of a Wideband Dual-Feed Circularly Polarized Antenna for Different Axial Ratio Requirements

“…Some minor discrepancies may be caused by the fabrication tolerance and measurement errors in the anechoic chamber. Table V compares the recently published dual-feed CP patch antennas [2], [4] and dipole antennas [6], [7] with the presented antenna. All of these antennas use branch-line coupler as the feed network.…”

A Simple and Efficient Adaptive ISM-Band Antenna Based on a Reconfigurable Optically Driven Parasitic Structure

“…In order to minimize (7) and, according to the guidelines reported in [19,20], a suitable implementation of the PSO [21][22][23][24][25][26][27][28][29] and of a geometry generator, able to modify and control the reference geometrical parameters, have been integrated with a method-of-moments (MoM) [30] electromagnetic simulator. Starting from the set of trial arrays ζ…”

Design of a Wideband Circularly Polarized Cross-Dipole With Wide Axial-Ratio Beamwidth

“…In [9], an inverted, pyramidal, cavity-backed reflector is incorporated with the cross-dipole to produce a unidirectional radiation pattern with a wide 3 dB AR beamwidth of 110 • . In [10], four vertical parasitic elements are employed between a simple ±45 • dual-polarized radiator and ground to widen the 3 dB AR beamwidth of 195 • . In [11], the antenna is backed by a metallic cavity to provide a unidirectional radiation pattern with a wide 3 dB AR beamwidth of over 165 • .…”