Date of Award

8-17-2017

Document Type

Thesis

Degree Name

Master of Science (MS)

Department

Systems Engineering

First Advisor

Hussain Al-Rizzo

Abstract

Due to market trends and rapid development in the wireless technology, wearable devices are expected to become part of our daily life like Google Glass, health monitors, smart watches and so on. The electronics market has oriented toward portable and fancy flexible devices due to their invisibility, outstanding view and disposability. The past decade witnessed an extensive research focused on the development and optimisation of flexible displays. Flexible displays are considered as an appealing and promising technology due to their low profile, low cost, light weight, and portability. Wearable displays deemed as a promising technology applicable to a wide spectrum of applications such as medical, military, entertainment and wireless communication. Investigating the effects of thin flexible substrates on wearable antennas near down the choices to the designer and enrich the topic with enough information about selecting the appropriate substrate properties. Moreover, this research attempts to answer a major question about either considering the presence of substrates or being excluded in the design simulation. In this thesis, different types of substrates have been chosen in the designs with different feeding techniques to illustrate the effects of the substrate properties on the performance of the antennas. Ultralam 3850 with two thicknesses (25μm and 50μm) and Roger R03035 with a thickness of 130μm have been implemented to fabricate the designs. The simulation settings required to achieve reliable characterization of the performance metrics in terms of impedance matching and far-field radiation patterns are implemented. From the crucial factors in the design of patch antennas are the selection of the suitable substrate thickness and dielectric constant (εr) to minimise substrate losses and improve antenna’s performance. Substrate thicknesses from 25μm to 125μm along with dielectric constant ranging from 1 to 9 have been chosen to reveal the effects of changing the substrate properties on the performance of the antennas in the simulation stage. Two designs were implemented and carefully studied using a dense mesh which are UWB Printed Monopole Antenna (PMA) and Printed Trapezoidal Monopole Antenna (PTMA). The antennas were designed and simulated using the High-Frequency Structure Simulator (HFSS) from ANSYS. Prototypes were fabricated using photolithography microfabrication technique and measured it in an anechoic chamber using Vector Network Analyzer (VNA).

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