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Type: Theses
Title: Analysis, design and optimisation of various antenna types based on equivalent magnetic-current concept
Author: Nguyen Trong, Nghia
Issue Date: 2017
School/Discipline: School of Electrical and Electronic Engineering
Abstract: The field equivalence principle is a classical technique, simple to use but remarkably effective to analyse aperture antennas. For most of thin planar structures, the aperture can be approximated as perfect magnetic conductor. Thus, the field equivalence principle typically yields a well-approximated equivalent problem that is much easier to solve than the original geometry. Inspired by this principle, a wide range of novel antenna structures are proposed in this thesis. These structures are further developed, optimised and tailored for various practical applications. Three main types of antennas are investigated, including travelling-wave antennas, low-profile monopolar antennas and reconfigurable antennas, corresponding to three major parts of this dissertation. The first part examines various realisations of travelling-wave half-mode substrate- integrated waveguide (HMSIW) antennas and their optimisations. This type of antenna is equivalent to a magnetic dipole. In this part, the core contribution is a generalised semi-analytical model to effectively analyse continuous-source travelling-wave antennas, based on which different optimisation techniques for bandwidth and radiation patterns are proposed. An optimisation procedure that includes parameter uncertainties is also demonstrated. The second part focuses on a type of low-profile monopolar antennas that can be interpreted as magnetic-current loops using the field equivalence principle. The main contributions are different configurations of symmetrical radiating slots that act as additional magnetic-current loop sources. The last major part covers a wide range of reconfigurable antennas targeting various applications. These includes a family of stub-loaded substrate-integrated antennas, a circular resonant cavity, and low-profile monopolar antennas that have been introduced in the second major part. These antennas not only cover three main application types of reconfigurable antennas, i.e. frequency- , polarisation-, and pattern-tunability, but also combine those in a single device. Moreover, significant improvements in performances compared to antennas available in the literature are demonstrated. Overall, the thesis provides different frameworks to design many types of antennas. The analytical models, using the field equivalence principle as a common fundamental technique, provide not only thorough understandings on antennas’ radiation mechanisms but also an effective means for rapid antenna optimisations.
Advisor: Fumeaux, Christophe
Kaufmann, Thomas
Dissertation Note: Thesis (Ph.D.) -- University of Adelaide, School of Electrical and Electronic Engineering, 2017
Keywords: field equivalence principle
magnetic current
leaky-wave antenna
travelling-wave antenna
monopolar antenna
reconfigurable antenna
Provenance: This electronic version is made publicly available by the University of Adelaide in accordance with its open access policy for student theses. Copyright in this thesis remains with the author. This thesis may incorporate third party material which has been used by the author pursuant to Fair Dealing exceptions. If you are the owner of any included third party copyright material you wish to be removed from this electronic version, please complete the take down form located at:
DOI: 10.25909/5bd12bb4c8d49
Appears in Collections:Research Theses

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