Liquid Dielectric Resonator Antenna With Circular Polarization Reconfigurability

A novel liquid dielectric resonator antenna with circular polarization (CP) reconfigurability is investigated in this communication. The fluidic dielectric for this design is ethyl acetate ( $\varepsilon _{\text {r}} =6.6$ ) which is held by a container fabricated by 3-D printing technology and excited by a single probe. To realize the CP reconfigurability, the container is designed with two zones: left and right zones. Therefore, the proposed antenna can be switched between two different states: when the liquid solution is injected into the left zone, it can realize left hand CP, on the other hand, if the fluidic dielectric is pumped into the right zone, it can obtain right hand CP. Consequently, the CP reconfigurability is obtained by flowing liquid control of the ethyl acetate solution. For demonstration, the proposed antenna is design at 2.4 GHz for RFID application with a broad impedance bandwidth (SWR < 2) of 35.6% which fully cover the wide axial ratio (AR) bandwidth (AR < 3 dB) of 16.3%. Finally, good agreement is achieved between the measurement and simulation.