Reconfigurable Antennas Using Liquid Crystalline Elastomers

Authors

John Gibson, Florida International UniversityFollow

Document Type

Dissertation

Degree

Doctor of Philosophy (PhD)

Major/Program

Electrical Engineering

First Advisor's Name

Stavros Georgakopoulos

First Advisor's Committee Title

Committee Chair

Second Advisor's Name

Nezih Pala

Second Advisor's Committee Title

Committee Member

Third Advisor's Name

Taylor Ware

Third Advisor's Committee Title

Committee Member

Fourth Advisor's Name

Jean Andrian

Fourth Advisor's Committee Title

Committee Member

Fifth Advisor's Name

Félix Miranda

Fifth Advisor's Committee Title

Committee Member

Sixth Advisor's Name

Kinzy Jones

Sixth Advisor's Committee Title

Committee Member

Keywords

Reconfigurable Antennas, Shape Memory Polymers, Liquid Crystalline Elastomers, Passive Temperature Sensor

Date of Defense

3-29-2018

Abstract

This dissertation demonstrates the design of reversibly self-morphing novel liquid crystalline elastomer (LCE) antennas that can dynamically change electromagnetic performance in response to temperature. This change in performance can be achieved by programming the shape change of stimuli-responsive (i.e., temperature-responsive) LCEs, and using these materials as substrates for reconfigurable antennas. Existing reconfigurable antennas rely on external circuitry such as Micro-Electro-Mechanical-Systems (MEMS) switches, pin diodes, and shape memory alloys (SMAs) to reconfigure their performance. Antennas using MEMS or diodes exhibit low efficiency due to the losses from these components. Also, antennas based on SMAs can change their performance only once as SMAs response to the stimuli and is not reversible. Flexible electronics are capable of morphing from one shape to another using various techniques, such as liquid metals, hydrogels, and shape memory polymers.

LCE antennas can reconfigure their electromagnetic performance, (e.g., frequency of operation, polarization, and radiation pattern) and enable passive (i.e., battery-less) temperature sensing and monitoring applications, such as passive radio frequency identification device (RFID) sensing tags. Limited previous work has been performed on shape-changing antenna structures based on LCEs. To date, self-morphing flexible electronics, including antennas, which rely on stimuli-responsive LCEs that reversibly change shape in response to temperature changes, have not been previously explored. Here, LCE antennas will be studied and developed. Also, the metallization of LCEs with different metal conductors and their fabrication process, by either electron beam (E-Beam) evaporation or optical gluing of the metal film will be observed. The LCE material can have a significant impact on sensing applications due to its reversible actuation that can enable a sensor to work repeatedly. This interdisciplinary research (material polymer science and electrical engineering) is expected to contribute to the development of morphing electronics, including sensors, passive antennas, arrays, and frequency selective surfaces (FSS).

Identifier

FIDC006536

Recommended Citation

Gibson, John, "Reconfigurable Antennas Using Liquid Crystalline Elastomers" (2018). FIU Electronic Theses and Dissertations. 3706.
https://digitalcommons.fiu.edu/etd/3706