A Reconfigurable Microstrip Patch Antenna With Switchable Liquid-Metal Ground Plane

This letter presents a novel reconfigurable microstrip patch antenna that is reconfigured using liquid metal. The proposed antenna employs two approaches in unison to switch the direction of the main beam. Specifically, the antenna uses the parasitic steering approach together with a novel switchable ground plane. The antenna operates at 5.9 GHz. It consists of a driven patch surrounded by four parasitics. All five elements are circular disk resonators. Each of the parasitic resonators incorporates a drill hole. The drill holes can be filled or emptied of liquid metal to control the behavior of the parasitics. The ground plane incorporates two reconfigurable segments. The switchable ground plane can be reshaped by adding or removing the additional segments of ground plane which are formed from liquid metal. To the best of the authors’ knowledge, this is the first antenna that is capable of reconfiguring its radiation pattern by reshaping the ground plane using liquid metal. A hardware prototype of the antenna was fabricated and measured. The measurement results show that the antenna can switch between five different beam directions, namely: 0°, ±20°, and ±40°. The design has only 0.5 dB of scan loss across the beam switching range.