Temperature and Frequency Dependence of Complex Permittivity in Metal Oxide Dielectrics: Theory, Modelling and Measurement
Authors: Breeze, Jonathan
Free Preview- Nominated as an outstanding Ph.D. thesis by Imperial College London, United Kingdom
- Demonstrates for the first time that a theory of harmonic phonon coupling can effectively predict the complex permittivity of metal oxides as a function of temperature and frequency
- Provides invaluable insights into the mechanisms of dielectric loss in oxides
- Paves the way for engineering better dielectrics, especially for the rapidly developing terahertz field
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- About this book
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This thesis investigates the dielectric properties of metal-oxide ceramics at microwave frequencies. It also demonstrates for the first time that a theory of harmonic phonon coupling can effectively predict the complex permittivity of metal oxides as a function of temperature and frequency. Dielectric ceramics are an important class of materials for radio-frequency, microwave and emergent terahertz technologies. Their key property is complex permittivity, the real part of which permits the miniaturisation of devices and the imaginary part of which is responsible for the absorption of electromagnetic energy. Absorption limits the practical performance of many microwave devices such as filters, oscillators, passive circuits and antennas. Complex permittivity as a function of temperature for low-loss dielectrics is determined by measuring the resonant frequency of dielectric resonators and using the radial mode matching technique to extract the dielectric properties.
There have been only a handful of publications on the theory of dielectric loss, and their predictions have often been unfortunately unsatisfactory when compared to measurements of real crystals, sometimes differing by whole orders of magnitude. The main reason for this is the lack of accurate data for a harmonic coupling coefficient and phonon eigenfrequencies at arbitrary q vectors in the Brillouin zone.
Here, a quantum field theory of losses in dielectrics is applied, using results from density functional perturbation theory, to predict from first principles the complex permittivity of metal oxides as functions of frequency and temperature.
- About the authors
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My principal research interests lie in room-temperature maser, the measurement and modelling of the dielectric properties of microwave dielectric materials, the design of high Q-factor and Purcell-factor resonators and density functional calculations of materials. Other research areas are microwave filter design, photonic bandgap structures, metamaterials and the measurement of the electrical and magnetic properties of thin films at microwave frequencies.
- Table of contents (8 chapters)
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Introduction
Pages 1-12
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Modelling Dielectric Resonators
Pages 13-41
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Measurement of Dielectric Properties
Pages 43-67
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Lattice Dynamics and Density Functional Perturbation Theory
Pages 69-86
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Harmonic Properties of Metal Oxide Dielectrics
Pages 87-109
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Table of contents (8 chapters)
- Download Sample pages 2 PDF (688.5 KB)
- Download Table of contents PDF (118.6 KB)
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Bibliographic Information
- Bibliographic Information
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- Book Title
- Temperature and Frequency Dependence of Complex Permittivity in Metal Oxide Dielectrics: Theory, Modelling and Measurement
- Authors
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- Jonathan Breeze
- Series Title
- Springer Theses
- Copyright
- 2016
- Publisher
- Springer International Publishing
- Copyright Holder
- Springer International Publishing AG
- eBook ISBN
- 978-3-319-44547-2
- DOI
- 10.1007/978-3-319-44547-2
- Hardcover ISBN
- 978-3-319-44545-8
- Softcover ISBN
- 978-3-319-83076-6
- Series ISSN
- 2190-5053
- Edition Number
- 1
- Number of Pages
- XX, 167
- Number of Illustrations
- 51 b/w illustrations, 27 illustrations in colour
- Topics
