Using Gallium-Based Liquid Metal to Create Beam Switchable Bull's Eye Antennas

This paper presents two designs for beam switchable Bulls Eye antennas. The first beam switchable antenna was generated by dividing a Bull's Eye antenna into two symmetrical halves. We can then reconfigure the beam direction by effectively switching each half on and off. We refer to this design, throughout the paper, as a beam switchable Bull's Eye antenna. The second design effectively involves switching between two different antenna types having different main beam directions, namely: a Bull's Eye and a Yagi-Uda. We refer to this design, throughout the paper, as a two-mode antenna. In order to enable us to switch between the two different types of antennas, we nest the geometrical features of the Yagi-Uda antenna inside those of the Bull's Eye antenna. The beam switchable Bull's Eye antenna operates at a frequency of 10 GHz and the two-mode antenna operates at a frequency of 15 GHz. Both antennas incorporate a series of fluidic channels. In practical prototypes of the antennas, they would be reconfigured by filling and emptying different combinations of channels with Gallium-based liquid metal. The main beam of the beam switchable Bull's Eye antenna can scan between ±14°. At 10 GHz, simulated realized gain was 12.1 dBi, with a sidelobe level (SSL) of -9.3 dB. The simulated main beam of the two-mode antenna can be switched from 1° (for the Bull's Eye mode) to 74° (for the Yagi-Uda mode). The simulated realised gain was 13 dB and 16.2 dB for the for Yagi-Uda and Bull's Eye mode, respectively.