Electrical and Computer Engineering ETDs

Publication Date

Spring 4-15-2021

Abstract

While liquid metals, such as mercury, have been used in electronics for quite some time, the non-toxic gallium based liquid metals have caused an increase in research for liquid metal applications. Some of the potential applications that have been previously presented range from reconfigurable antennas, strain and pressure sensors, and speakers and microphones to name a few. The focus of this work is to provide further research into the use of gallium based liquid metals as a reconfigurable antenna, a phase shifter, and an array. This is done by designing, constructing, and characterizing each of these reconfigurable liquid metal (LM) devices as a demonstration of their possibilities.

Much of the antenna research using gallium based LM focuses on a design that varies the amount of LM in a cavity to reconfigure the antenna and manipulate the desired characteristics, such as the resonance, radiation pattern, or input impedance. Presented in this research is how one may control the characteristics of the device by stretching rather than filling and vacating a cavity.

Presented first is a simple stretchable LM monopole antenna. A 3D printed cylinder is made as a mold to create a stretchable polymer with a cavity for the LM. Once the polymer is cured and removed from the mold, its cavity is filled with LM and capped off. Tuning the antenna is accomplished simply by stretching the antenna to increase its length and modify its resonant frequency. Simulations and measurements of the antenna show that the stretchable LM antenna can be designed to satisfy an application in need of a wideband antenna.

Second, a stretchable liquid metal phase shifter, made much the same as the monopole antenna, is presented. Based on a coax design, when stretched, the path lengthens and phase changes. Simulations and measurements show the available phase shift almost triples what was previously available for a LM phase shifter.

Lastly, an array combining two of the stretchable LM antennas and the stretchable LM coaxial phase shifter is presented and constructed. Resonant frequency tuning is still obtained by stretching the monopole antennas, but the stretchable phase shifter adds the ability to change the phase of the input signal to steer the antenna beam. Simulations and measurements confirm the ability to rotate the beam 180° (end-to-end) at three different frequencies.

Keywords

antenna, array, liquid metal, phase shifter, reconfigurable, stretchable

Document Type

Dissertation

Language

English

Degree Name

Electrical Engineering

Level of Degree

Doctoral

Department Name

Electrical and Computer Engineering

First Committee Member (Chair)

Christos Christodoulou

Second Committee Member

Mark Gilmore

Third Committee Member

Nathan Jackson

Fourth Committee Member

Youssef Tawk

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