Yttria-Stabilized Zirconia (YSZ) Based Antennas for High Temperature Applications

Abstract

With the importance of work achieved by first responders, it is important that they retain solid and reliable communication in a variety of difficult and life-threatening situations. A major component that contributes to the viability of these devices is the antenna that retains its operation under high stress and high-temperature situations while not contributing to the decrease in mobility and operations of the user. An antenna capable of covering these requirements comes in the form of a patch antenna, both in size and operational integrity. The stress and temperature requirements, however, would be withstood by the antenna through the introduction of a new, usable substrate. This substrate is ZRC composed of Yttria-Stabilized Zirconia (YSZ), a chemical compound that has the capacity of withstanding extreme temperatures, changes in temperatures, and a structural integrity to be successfully integrated within existing first-responder equipment without changing the operational characteristics of the antenna constructed. Presented below are three projects serving as an exploration into ZRC and its possible integrated as a variety of antenna systems. The first project presents a characterization of the material for its electrical properties. This project consists of two individual ZRC substrates that serve as two structures. The first structure contains a centered transmission line of 3 mm thickness spanning the length of the substrate and connected by two ports. The second structure modifies the transmission line of the first by applying a stub structure at the middle of the transmission line as it spans the length of the substrate. Both structures were constructed through the application of multi-layer application technique consisting of cobalt (Co) and Aluminum (Al). The phase differences and isolation of these structures compared to each other allow the determination of different electrical properties of the ZRC substrate. The second project is the first construction of a monopole coplanar waveguide (CPW) antenna on this substrate. The antenna consists of a rectangular resonator with a ground plane of two parts on either side of the antenna feedline. The antenna was able to achieve a bandwidth of 1.6 GHz (77%) at a peak of about -50 dB at 2.55 GHz. The antenna also exhibits a peak gain of about 4 dB and stays above 2 dB gain throughout the S-band in which the antenna operates. The final project expands on the capacity and workable viability of the antenna by introducing a multi-input-multi-output (MIMO) design constructed on a square ZRC substrate, along with a study of th effect of a new dielectric constant introduced to a created design. The initial antenna consists of 4 monopole antenna elements mounted on the center of each side of the square substrate. The working bandwidth of each antenna was about 100 MHz (4%), from 2.45 GHz to 2.55 GHz. An isolation below -15 dB was achieved between each element. At least 3 dB gain was obtained through workable range, peaking at 3.34 dB at the center frequency 2.5 GHz. The MIMO antenna with updated characteristics provides a bandwidth of 80 MHz (3.2%) from 2.46 GHz to 2.54 GHz. A similar isolation was achieved, with all elements below -15 dB, and the gain was above 2.5 dB in the operating bandwidth, with a peak of gain just below 3.5 dB. The characterization of this material presents a greater understanding of the substrate characteristics, and the two antennas provide options for expanding antenna implementations for use in harsh environments.