Microwave dielectric materials play a key role in our global society with a wide range of applications, from terrestrial and satellite communication including software radio, GPS, and DBS TV to environmental monitoring via satellite.
A small ceramic component made from a dielectric material is fundamental to the operation of filters and oscillators in several microwave systems. In microwave communications, dielectric resonator filters are used to discriminate between wanted and unwanted signal frequencies in the transmitted and received signal. When the wanted frequency is extracted and detected, it is necessary to maintain a strong signal. For clarity it is also critical that the wanted signal frequencies are not affected by seasonal temperature changes. In order to meet the specifications of current and future systems, improved or new microwave components based on dedicated dielectric materials and new designs are required. The recent progress in microwave telecommunication, satellite broadcasting and intelligent transport systems (ITS) has resulted in an increased demand for Dielectric Resonators (DRs). With the recent revolution in mobile phone and satellite communication systems using microwaves as the propagation media, the research and development in the field of device miniaturization has been a major challenge in contemporary Materials Science. In a mobile phone communication, the message is sent from a phone to the nearest base station, and then on via a series of base stations to the other phone. At the heart of each base station is the combiner/filter unit which has the job of receiving the messages, keeping them separate, amplifying the signals and sending then onto the next base station. For such a microwave circuit to work, part of it needs to resonate at the specific working frequency. The frequency determining component (resonator) used in such a high frequency device must satisfy certain criteria. The three important characterist
- collects together in one source data on all new materials used in wireless communication
- includes tabulated properties of all reported low loss dielectric materials
- in-depth treatment of dielectric resonator materials
Research scientists and engineers working in the area of wireless communication, postgraduate students in physical and chemical sciences, graduate and postgraduate students in electronic engineering.
Foreword by Prof. Neil Alford, F R Eng. Imperial College London Chapter 1. Introduction
Chapter 2. Measurement of microwave dielectric properties and factors affecting them
2.1. Permittivity 2.2. Quality factor (Q) 2.3. Measurement of microwave dielectric properties 2.3.1. Hakki and Coleman (Courtney) method 126.96.36.199. Measurement of Permittivity 188.8.131.52. Measurement of loss tangent 2.3.2. TE01ƒÔ) mode dielectric resonator method 2.3.3. Measurement of quality factor by stripline method 2.3.4. Whispering Gallery Mode resonators 2.3.5. Split Post Dielectric Resonator (SPDR) method 2.3.6. Cavity Perturbation method 2.3.7. TM010 mode and Re-entrant cavity method 2.3.8. TE01n mode cavities 2.4. Estimation of dielectric loss by spectroscopic methods 2.5. Factors affecting the dielectric loss 2.6. Correction for porosity 2.7. Calculation of permittivity using Clausius Mossotti equation 2.8. Measurement of temperature coefficient of resonant frequency 2.9. Tuning of resonant frequency References
Chapter 3. Microwave dielectric materials in the BaO-TiO2 system
3.1. Introduction 3.2. BaTi4O9 3.2.1. Microwave dielectric properties 3.3. BaTi5O11 3.4. Ba2Ti9O20 3.4.1. Preparation 3.4.2. Structure 3.4.3. Properties 3.5. BaTi4O9/Ba2Ti9O20 composites 3.6. Conclusion References <BR id="CRLF"
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- 23rd June 2008
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Dr. M T Sebastian is currently Deputy Director, National Institute for Interdisciplinary Science and Technology at Trivandrum in India. He obtained his Ph.D. in Physics from Banaras Hindu University in 1983. He taught physics at Cochin University of Science & Technology during 1984-87. He was an Alexander Von Humboldt Fellow in Germany and Nokia Visiting Fellow in Finland. He has done extensive researches in USA, UK, France, Germany, Australia, Czech Republic, Australia, Japan and Finland. He has co-authored the book “Random non-random and periodic faulting in crystals” published by Gordon & Breach Science publishers (1994). He has published more than 160 research papers in international refereed journals and possesses several patents. His research interests are microwave ceramic dielectric resonators, perovskites electrode materials, crystal growth and defect characterization, X-ray scattering from disordered structures, electronic packaging materials.
National Institute for Interdisciplinary Science and Technology