Leaky wave antennas for remote vital signs monitoring at MM-wave frequencies

Mingle, Solomon ORCID: 0000-0001-6749-7179 (2023). Leaky wave antennas for remote vital signs monitoring at MM-wave frequencies. University of Birmingham. Ph.D.

Preview

Mingle2023PhD.pdf
Text - Accepted Version
Available under License All rights reserved.
Download (11MB) | Preview

Abstract

In this thesis, a novel leaky wave antennas (LWAs) of the Fabry-Perot type (FP) with significantly improved gain and beam scanning capabilities based on periodic metasurfaces for remote vital sign monitoring (RVSM) in the millimetre waveband (50 – 68 GHz) are presented. The LWA design technique presented overcomes the difficulties associated with the fabrication and implementation of traditional designs for millimetre-wave antennas. This technique uses a simple feed between a partially reflective surface (PRS) and a high impedance surface (HIS) to achieve a leaky wave and beam scanning effect for RVSM. Periodic arrays, also known as frequency selective surfaces (FSS) due to their filtering capabilities, were used to determine partial reflections. First, a theoretical approximate model was used to gain an understanding of the physical behaviour of the antenna. The reflection characteristics of PRS and HIS determined using plane wave modal analysis were related to the performance of the antenna. The findings of this study served as guidelines for the development of single and double-layer array designs optimised for both high gain and beam scanning performance. An experimental study on RVSM was conducted using the proposed LWAs and compared with a conventional contact device to verify the accuracy of the results. It was found that the proposed LWAs can detect heart rate and breathing rate with 93% accuracy, which is a good match with the contact device. This research work has contributed to the current knowledge on (i) the design and testing of LWAs with and without HIS configuration to achieve high gains of 20 dBi and 22 dBi for short (1 m) and long (2 m) distances RVSM, (ii) the design of multilayer LWAs with improved bandwidth (8 GHz) and higher gain (24 dBi) for RVSM at 4 m, and (iii) the design and testing of bidirectional LWAs based on dielectric image lines with a gain of 19 dBi and 70o beam scanning through the broadside for single and multiple target RVSM at 1.5 m. The above contributions and findings of the proposed LWAs for RVSM have been published.

Type of Work:

Thesis (Doctorates > Ph.D.)

Award Type:

Doctorates > Ph.D.

Supervisor(s):