Reconfigurable Water-Based Antennas

Water is an inexpensive, abundant and biofriendly material for many microwave applications. The high permittivity of water at microwave frequencies, as well as its liquid state, enables compact and reconfigurable dielectric resonators, which can be used in antenna configurations and functional material structures such as metasurfaces. In this work, we present two water-based antennas with reconfigurable responses operating in the lower microwave frequencies. First, we present a highly subwavelength antenna operating as a magnetic dipole antenna. The second is a Huygens antenna with an increased directivity due to a balanced excitation of dipole modes. Both numerical and experimental results are presented. The proposed water-based antennas may serve as an easy–to– fabricate and cheap alternative for the VHF and low end of the UHF bands.