A Water-Based Huygens Dielectric Resonator Antenna

With its high-permittivity in the microwave frequency range, water has the potential as an alternative, inexpensive, bio-friendly and abundant material for many microwave applications such as dielectric resonator antennas and tunable metamaterials. Huygens antennas, composed of single-element structures supporting a special combination of electric and magnetic modes, provide an alternative route for compact and directive antennas. In this work, we investigate a subwavelength water-based Huygens dielectric resonator antenna with strongly excited electric and magnetic dipoles at around 350 MHz. Our antenna leads to the directivity of 6 and a radiation front-to-back ratio of 40.3 dB. Additionally, good matching to the feed-line and the surrounding free space were achieved with a reflection coefficient of -38.3 dB and a total efficiency of 57.8 %. The antenna was fabricated and characterized with excellent agreement between the measurements and the numerical results. Furthermore, several means of tuning the antenna were tested numerically and experimentally. We believe that the proposed water-based Huygens dielectric resonator antenna may serve as an easy-to-fabricate and cheap alternative for the VHF and low end of the UHF bands.