A wideband polarization reconfigurable isosceles trapezoidal monopole antenna

Abstract

In this article, a polarization reconfigurable isosceles trapezoidal monopole antenna for the circular polarization (CP) is presented. A trapezoidal monopole and the ground plane are on the same side of the dielectric substrate. The monopole is excited by a reconfigurable T‐shaped 50 Ω microstrip feed line and reconfigurable vertical slots are incorporated in the ground plane to realize switchable wideband CP. For the different switching states of the p‐i‐n diodes, linear polarization, left‐handed and right handed CP can be achieved in the boresight direction (+z direction). The antenna prototype is fabricated and tested. The measured reflection coefficient bandwidth (|S11| < −10 dB) is 31.2% (2.13 ‐ 2.91 GHz) and axial ratio bandwidth (axial ratio < 3 dB) is 22% (2.18 ‐ 2.72 GHz) for the CP. The measured reflection coefficient bandwidth is 18.56% (2.15 ‐ 2.59 GHz) for linear polarization.

Dual‐band polarisation reconfigurable grounded fractal slot antenna

“…A comparison between the proposed fractal inspired antenna and previously reported polarisation reconfigurable antenna is summarised in Table 3. The antenna presented in [1–13, 16–20], the switching element is placed within the radiating element or signal path and require complex biasing network for the switching. The proposed antenna is small in profile and large overall CP bandwidth.…”

“…In the recent past, several polarisation reconfigurable antennas radiating circular polarisation have been proposed [1–16]. These antennas utilise several techniques, such as switchable slots in the radiating element, switchable/reconfigurable feed network, reconfigurable slots and stubs connected to the ground plane etc.…”

“…In the recent past, two reconfigurable grounded L‐shaped stubs placed on both sides of a monopole antenna [15] are used to control the polarisation. In [16], a trapezoidal monopole antenna having reconfigurable feed line and switchable grounded slots are proposed. A monopole antenna with switchable corner and loaded with a metasurface to enhance CP bandwidth is presented in [17] and a monopole antenna with a switchable square ring is presented in [18].…”

“…A reconfigurable L‐shaped feed line exciting a rectangular slot in [20] is a dual‐band polarisation reconfigurable antenna. The antennas presented in [1–16] are limited by the narrow overlapping reflection and axial ratio (AR) bandwidths and provide single band CP reconfigurability. The switching elements are embedded within the radiating element in the antennas presented in [17–20], and hence the biasing network affects the antenna performance [21].…”

A polarization and band reconfigurable cross-slot antenna for multiband application

“…Various techniques are used to alter the current path within the antenna by integrating RF switches to achieve reconfigurability e.g. by placing the RF switching element within the feed network, radiating element, or in the ground plane [2,3].…”