Reconfigurable RHCP-to-LP Helical Antenna Made of Pure Water

A polarization-reconfigurable pure-water helical antenna operating at 1.6 GHz is presented in this paper, which consists of two water helixes with inversed rotational directions connected in series. By changing the water height, a switch between right-handed circular polarization (RHCP) and linear polarization (LP) is achieved. Measured results show that the proposed RHCP-to-LP antenna has an overall impedance bandwidth (|S₁₁| <; -10 dB) of 79.1% for the two polarizations, and an axial ratio (AR) bandwidth (AR<; 3 dB) of 51.4% for RHCP.

I. Introduction

There has been a growing interest in designing water antennas in recent years due to its transparency, reconfigurability, and low cost [1]. Water has been used to design different kinds of antennas, such as dielectric resonator antennas (DRA) [2], leaky-wave antennas [3], monopole antennas [4], patch antennas [5], and spiral antennas [6]. In [2], a traditional dielectric resonator antenna made of water was proposed. In [3], a water leaky-wave antenna was reported. In [4], a frequency reconfigurable monopole water antenna was presented. In [5], a novel water dense dielectric patch antenna (DDPA) fed by an L-shaped probe was designed and investigated. A polarization reconfigurable Archimedean spiral antenna with two water arms fed by a parallel strip line with broadband characteristics was designed in [6].