Additively Manufactured Reconfigurable Liquid Metal Monopole Antenna Using Reservoir‐Based Feed System and Pneumatic Control

ABSTRACT Reconfigurable antennas, which are capable of changing properties such as their resonant frequency, are becoming increasingly necessary for modern wireless communication systems. A variety of reconfigurable antennas have been developed, including those which use liquid metals as their conductors to adjust electrical length. However, monopole liquid metal‐based antennas suffer from a variety of issues, such as the need for a liquid metal feed system that does not act as an undesired antenna. To overcome this issue, using reservoirs has proven useful, but current attempts have resulted in devices requiring either complex fabrication or control methods. In this study, an additively manufactured reconfigurable liquid metal monopole antenna is presented, which is fed by a reservoir of liquid metal and whose electrical length is controlled pneumatically using a syringe. The liquid metal used is eutectic gallium‐indium, which is a nontoxic liquid metal often used in place of mercury. The antenna is characterized at liquid metal heights ranging from 30 to 65 mm, resulting in a −10 dB bandwidth of 1.27 GHz from 1.08 to 2.35 GHz. The calculated tuning range and tuning ratio are also found to be 74.1% and 2.18. A sensitivity to temperature is also shown, with an increase in temperature leading to an increase in resonant frequency. This study not only adds to the existing body of liquid metal monopole antennas found in the literature, but also demonstrates a relatively simple structure and control method.