Advanced Design Techniques and Materials for Miniaturization, Efficiency Enhancement, and Multi-Functional Operation in Wearable Antennas
Date
2023
Authors
Samal, Purna B.
Editors
Advisors
Fumeaux, Christophe
Chen, Shengjian Jammy
Chen, Shengjian Jammy
Journal Title
Journal ISSN
Volume Title
Type:
Thesis
Citation
Statement of Responsibility
Conference Name
Abstract
Wireless body area networks (WBANs) have become increasingly
popular in recent years due to their potential for remote health monitoring,
smart diagnosis, and location tracking. In such applications,
the antenna sub-system, which is responsible for wireless communications is an essential
component that defines the efficiency and reliability of the data exchange. It
is crucial for the WBAN antenna to be lightweight, compact, low-profile, and flexible
to offer comfort to the users when worn. Moreover, WBAN antennas are required
to be efficient and capable of providing multi-functional operation to better serve for
advanced applications. Therefore, to realize the immense potential of WBAN applications,
it is of paramount importance to address the current challenges of wearable
antenna design.
Flexible planar antennas with compact size are highly desirable for WBAN applications
due to their unobtrusive wearability and convenient integrability. To realize
such antennas, Chapter 3 of this thesis presents suitable miniaturization techniques for
wearable antennas. Firstly, the chapter introduces a simple antenna miniaturization
technique using manipulation of the resonant current path length. Secondly, a novel
3D-corrugated ground structure for miniaturizing wearable antennas is presented. It
is realized by single folding of the full ground plane located underneath the radiating
edges of the microstrip antenna. This structure provides additional capacitive and
inductive loading, which slows the wave propagation and makes the antenna appear
electrically longer. Importantly, such a structure can be applied to miniaturize existing
planar antennas with the ground plane while preserving their radiation performance.
Recently, non-conventional materials have become increasingly favourable in wearable
antenna design with the aim of achieving attractive features such as environmental
friendliness, mechanical flexibility, and low cost. However, they usually have high
conductor loss or dielectric loss, which result in low radiation efficiency. To address
this issue, Chapter 4 presents antenna design techniques to improve the radiation efficiency
of planar antennas implemented with lossy materials. The improvement technique
is based on two aspects: reducing the conductor loss by altering the radiator
shape to lower the maximum surface current density; and, introducing an elevated ground plane to reduce the dielectric loss by decreasing the electromagnetic energy
concentration trapped within the dielectric material. The technique can also be applied
to improve the efficiency of existing planar antennas while preserving their overall size
and radiation performance.
A single antenna possessing multi-functional capabilities is highly desirable for operation
at various frequencies with independent radiation characteristics. It offers greater
flexibility in adapting to changing wireless communications requirements and reduces
the size, weight, and cost of the wearable system. To achieve such functionalities,
Chapter 5 of the thesis presents a dual-band dual-mode antenna based on a highly
flexible polydimethylsiloxane (PDMS) substrate. The design technique features a systematic
design methodology that enables the independent control of the resonances
and offers high flexibility to adapt the design for specific frequencies of operation. The
design technique further extends by introducing a new hybrid-substrate method to
improve the radiation efficiency. Chapter 6 presents antenna design techniques for
achieving multi-band operation that covers the 2.45 and 5 GHz wireless local area network
(WLAN) bands and IEEE UWB high band. It presents a textile-based flexible
multi-band antenna with a full ground plane and introduces a design method that
incorporates optimization technique using characteristics mode analysis (CMA) to extend
the antenna working bandwidth.
In brief, this thesis introduces advanced antenna design techniques aimed at miniaturizing
wearable antennas, improving their efficiency, and enabling multi-functional
operation for WBAN applications.
School/Discipline
School of Electrical and Mechanical Engineering
Dissertation Note
Thesis (Ph.D.) -- University of Adelaide, School of Electrical and Mechanical Engineering, 2023
Provenance
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