Book contents
- Frontmatter
- Contents
- Preface
- Acknowledgements
- To the reader
- List of notation
- 1 An overview of computational electromagnetics for RF and microwave applications
- 2 The finite difference time domain method: a one-dimensional introduction
- 3 The finite difference time domain method in two and three dimensions
- 4 A one-dimensional introduction to the method of moments: thin-wire modelling
- 5 The application of the FEKO and NEC-2 codes to thin-wire antenna modelling
- 6 The method of moments for surface modelling
- 7 The method of moments and stratified media: theory
- 8 The method of moments and stratified media: practical applications of a commercial code
- 9 An introduction to the finite element method
- 10 A selection of more advanced topics on the finite element method
- Appendix A The Whitney element
- Appendix B The Newmark-β time-stepping algorithm
- Appendix C On the convergence of the MoM
- Appendix D Suggested exercises and assignments
- Appendix E Useful formulas for simplex coordinates
- Appendix F Web resources
- Index
8 - The method of moments and stratified media: practical applications of a commercial code
Published online by Cambridge University Press: 10 December 2009
- Frontmatter
- Contents
- Preface
- Acknowledgements
- To the reader
- List of notation
- 1 An overview of computational electromagnetics for RF and microwave applications
- 2 The finite difference time domain method: a one-dimensional introduction
- 3 The finite difference time domain method in two and three dimensions
- 4 A one-dimensional introduction to the method of moments: thin-wire modelling
- 5 The application of the FEKO and NEC-2 codes to thin-wire antenna modelling
- 6 The method of moments for surface modelling
- 7 The method of moments and stratified media: theory
- 8 The method of moments and stratified media: practical applications of a commercial code
- 9 An introduction to the finite element method
- 10 A selection of more advanced topics on the finite element method
- Appendix A The Whitney element
- Appendix B The Newmark-β time-stepping algorithm
- Appendix C On the convergence of the MoM
- Appendix D Suggested exercises and assignments
- Appendix E Useful formulas for simplex coordinates
- Appendix F Web resources
- Index
Summary
Printed antenna and microstrip technology: a brief review
Microstrip patch antennas are an example of a large class of modern antennas known as “printed antennas.” Microstrip was originally developed in the early 1950s as a transmission line, and the first publication on using this structure as a radiator appears to have been by Deschamp in 1953 [1, Section 1.1]. Almost twenty years then passed until the first patent of the modern microstrip antenna was registered in 1973 by Munson, although the structure was independently discovered in at least one other location.
Microstrip antennas are generally constructed using the same photo lithographic process using to create printed circuit boards. In their simplest form, radiation is due primarily to energy leaking out of the cavity formed by the patch located close to a ground plane; physically, the patch is simply a very wide microstrip line. For the basic rectangular patch, the radiation from two opposite sides reinforces, whereas that from the other two sides cancels. The patch is usually supported on a dielectric substrate of some form, primarily for structural reasons. Typical materials are Teflon and glass-reinforced plastics, as used in printed circuit board technology. Typical material properties for these are ∈r in the range from 2–2.5, and tan δ from 0.0004–0.002. High-∈r substrates such as alumina ceramics produce physically small patches, but with very limited bandwidth. Typical material properties in this case are: ∈r 9.7–10.3, tan δ ≈ 0.0004. For some applications, plastic foam substrates have been used. These materials (sometimes using cheap materials such as expanded polystyrene tiles) have properties close to free space: ∈r ≈ 1.05, and tan δ ≈ 0.0008.
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- Information
- Computational Electromagnetics for RF and Microwave Engineering , pp. 271 - 288Publisher: Cambridge University PressPrint publication year: 2005