Design of mechanically rotatable microstrip patch antennas using an asymmetric polariser for adaptive polarisation adjustment

Abstract

This paper proposes the design of a microstrip patch antenna with an asymmetric polariser for adaptive polarisation adjustment. The asymmetric polariser is placed in the outer perimeter of a circular radiating patch and is mechanically rotated from 0° to 360° to adjust the axial ratio (AR) and the tilt angle (TA). To verify the operating principle of the proposed antenna, its radiating properties are theoretically formulated based on the cavity model, and three sample antennas with different shapes of the polariser are fabricated to measure their antenna characteristics. Then, a field test is conducted to observe variations of the received signal strength for incoming signals with time‐varying polarisation properties. The results demonstrate that the mechanical rotation of the polariser is suitable to minimise the polarisation mismatch with improvement of the received signal strength from −44.0 to −30.3 dBm in a harsh multipath environment.

Design of patch antenna with polarization control module to achieve broad 3‐dB gain bandwidth over entire AR range

“…However, the matching bandwidth and the 3-dB gain bandwidth for each polarization are often too narrow for practical applications. 13 In this article, we propose a novel patch-antenna design with broad matching bandwidth and broad 3-dB gain bandwidth, which can adjust AR properties for various practical applications. The proposed antenna consists of a shorted radiating patch, an L-shaped indirect feed, and a polarization control module.…”

“…Various polarizations adjustment techniques, such as using parasitic elements, two‐port with a branch‐line coupler, and pin‐diode have been proposed to obtain axial ratio (AR) characteristics including linear, right‐hand circular (RHC), left‐hand circular (LHC), and elliptical polarizations (EP). However, the matching bandwidth and the 3‐dB gain bandwidth for each polarization are often too narrow for practical applications …”