The University of New South Wales Sydney, Australia RADIO FREQUENCY AND MICROWAVE DESIGN METHODS FOR MOBILE COMMUNICATIONS Marian Gabriel Banciu Thesis submitted in fulfilment of the requirements for the degree of Doctor of Philosophy School of Electrical Engineering and Telecommunications 2003 RF and Microwave Design Methods for Mobile Communication Abstract The Global System for Mobile communications (GSM), which covers 54% of the world’s mobile market, evolved into the General Packet Radio Service (GPRS). The thesis addresses interference suppression using new radio frequency (RF) and microwave design methods for GSM and GPRS. The overall outcome is interference reduction and enhanced network capacity, leading to superior quality of service (QoS) for wider area coverage. The main results can be summarized as follows • Design, manufacturing and characterisation measurements of new compact filters for GSM and GPRS base stations in order to reduce the out-of-band interference. It is shown that filters with novel microstrip resonators - dual mode filters and cross coupled filters - provide both a high degree of miniaturisation and narrow bandwidth. • Development of a new 3-D Finite-Difference Time-Domain (FDTD) design method for new microstrip filters. A non-homogeneous Perfectly Matched Layer (NH-PML) was implemented for Absorbing Boundary Conditions (ABC) to increase the accuracy of the FDTD method. Signal estimation techniques were developed to speed up FDTD computations. A novel design method based on neural networks (NN) and FDTD was implemented to reduce the total design time. • Investigation of High Temperature Superconductors (HTS) thin film resonators and antennas at microwave frequencies. High Q-factor HTS devices considerably enhance both the front-ends sensitivity and selectivity of wireless receivers. • Design, manufacturing and testing of radio frequency (RF) electronics for 16 elements GSM and GPRS Smart Antenna for multipath fading mitigation and for in-band interference including co-channel interference (CCI) suppression. i RF and Microwave Design Methods for Mobile Communication Acknowledgments First of all, I would like to express my gratitude to all the people in the Government of Australia, University of New South Wales, Faculty of Engineering and School of Electrical Engineering and Telecommunications who promoted research policies and maintained a research environment indispensable for this project. I would like to thank my supervisor Dr. R. Ramer for giving me the opportunity to work on microwave and RF design techniques for mobile communications at the University of New South Wales. I am grateful for all the given support and the essential guidance during my Ph.D. study. I wish to express my appreciation to my former co-supervisor Prof. T. Bao Vu and to Gary Jonas for their support during my two years long participation as a RF engineer in the “Smart Antenna for GSM” project. I would like to thank to Dr. E. Ambikairajah for his encouragements and for the inspiring lectures on Neural Networks and Applications. I am grateful to Dr. P. Rapajic for his encouragements and for his support during my activity as a tutor and laboratory demonstrator for the subject Mobile and Satellite Communications. I dedicate this work to my family. Lucrare dedicată familiei mele (Mihai, Doina, Elena, Emil, Zoica) Musical motto. Oedipus, challenging the Destiny, is defeating the Sphynx. George Enescu, opera “Oedipe” ii RF and Microwave Design Methods for Mobile Communication List of Publications [1] R. Ramer, M. G. Banciu, C. Constantin, G. J. Russell, T. B. Vu, “Superconducting Thin Films for Microwave Resonators”, Proceedings of the Asia-Pacific Microwave Conference, APMC ’97, 2-5 December 1997, pp. 121-123 [2] M. G. Banciu, R. Coca, R. Ramer, T. B. Vu, “Full Wave Computations for Microstrip Resonators and Antennas”, Proceedings of the 3rd Asia-Pacific Conference on Communications, APCC’97, 7-10 December, 1997, pp. 814-817 [3] M. G. Banciu, M. S. Pham, R. Ramer, T. B. Vu, “Preliminary Design and Fabrication of Microstrip HTS Antenna”, Proceedings of the 3rd Asia-Pacific Conference on Communications, APCC’97, 7-10 December, 1997, pp. 902-905 [4] M. G. Banciu, R. Ramer, “FDTD Method for Mobile Communicationss Filters”, Progress in Electromagnetics Research Symposium, PIERS 2000, Cambridge, Massachusetts, USA, July 2000 [5] M. G. Banciu, R. Ramer, “Analysis of Microstrip Circuits Using a Finite- Difference Time-Domain”, Proceedings of the 4th World Multiconference on Circuits, Systems, Communications and Computers, Proceedings CSCC 2000, Vouliagmeni, Greece, July 2000, ISBN 960-8052-19-X, pp 4611-4615 [6] M. G. Banciu, R. Ramer, “Analysis of Microstrip Circuits Using a Finite- Difference Time-Domain”, in Advances in Physics, Electronics and Signal Processing Applications, edited by N. E. Mastorakis, World Scientific and Engineering Society Press, Danvers, MA, USA, 2000, ISBN: 960-8052-17-3, pp. 156-160 [7] M. G. Banciu, R. Ramer, “A FDTD Method for Circuits on High Dielectric Constant Substrates”, Proceedings of the 5th International Symposium on Antennas, Propagation and Electromagnetic Theory, ISAPE 2000, Beijing, China, August 2000, pp. 219-222 [8] M. G. Banciu, R. Ramer, “Design of Microstrip Dual Mode Filters Using Finite-Difference Time-Domain Method”, Proceedings of the Asia-Pacific Microwave Conference – APMC 2000, December 2000, Sydney, vol. 1, pp. 975-978 iii RF and Microwave Design Methods for Mobile Communication [9] R. Ramer, M. G. Banciu, “High Temperature Superconducting Thin Films for Microwave Devices”, Proceedings of the XV-th International Conference on Microwave Ferrites, Rokosowo, Poland, September 2000, pp. 120-123 [10] R. Ramer, M. G. Banciu, E. Dimitriu, M. S. Pham, T. B. Vu, “Design and Fabrication Preamble of a Microstrip HTS Antenna”, Industrial Ceramics, vol. 21, no. 2, ISSN 1127-7588, pp. 111-113 [11] M. G. Banciu, R. Ramer, A. Ioachim, “Microstrip Filters Using New Compact Resonators”, Electronics Letters, vol. 38, 2002, pp. 228-229 [12] M. G. Banciu, E. Ambikairajah, R. Ramer, “Microstrip Filter Design Using FDTD and Neural Networks”, Microwave and Optical Technology Letters, vol. 34, No. 3, 2002, pp. 219-224. [13] M. G. Banciu, R. Ramer, A. Ioachim, “Compact Microstrip Resonators for 900 MHz Frequency Band”, to appear in IEEE Microwave and Wireless Components Letters, May 2003 [14] M. G. Banciu, A. Ioachim, R. Ramer, “New Microstrip Resonators and Filters for GSM / GPRS”, Proceedings of the 25th Edition of the International Semiconductor Conference, CAS 2002, (IEEE Romania Section), Sinaia, Romania, 2002, vol. 1, pp. 41-44 [15] M. G. Banciu, A. Ioachim, R. Ramer, “New Microstrip Filters for GSM / GPRS”, to appear in the Proceedings of the EMFM 2002 (former ICMF), (IEE Slovakia Section), Bratislava, Slovakia, September 2002 [16] A. Ioachim, R. Ramer, G. Banciu, “X-Band High Peak Power Ferrite Devices“, presented to Progress in Electromagnetic Research, PIERS 2002, Cambridge, MA, July 2002 [17] M. G. Banciu, P. Rapajic, R. Ramer, “RF Electronics for GSM/GPRS Smart Antenna”, Proceedings of the 25th Edition of the International Semiconductor Conference, CAS 2002, (IEEE Romania Section), Sinaia, Romania, 2002, vol. 1, pp. 45-48 iv RF and Microwave Design Methods for Mobile Communication Table of contents 1. Introduction …………………………………………………………………. 1 1.1. Thesis outline ………………………………………………………... 1 1.2. Summary of Thesis Contributions …………………………………… 3 References ………………………………………………………………… 4 Acronyms and Abbreviations in Chapter 1 …………………………….… 8 2. Background Knowledge …………………………………………....…..…… 9 2.1. Fundamental Concepts in Mobile Communications ………..….....…. 9 2.1.1. Global System for Mobile Communication ………...……... 15 2.1.2. General Packet Radio Service ………………………...….… 17 2.2. Finite Difference Time Domain Method …...............………………… 18 2.3. Elements of Microwave Filters …………………………………..….. 24 2.3.1. Microstrip Filters …………….………………………..….… 30 2.4. High Temperature Superconductivity for Mobile Communications …………………………………………………….. 32 2.4.1. The Cryogenic Front Ends …...………………………..…... 34 2.4.2. HTS Antennas ……………......………………………..…... 38 2.5. Antenna Array Concepts…………………..…………………….…… 39 2.5.1. Smart Antennas……………......………………………..…... 42 2.6. Chapter Summary ……………………………………………….…… 46 References …………………………………………....…………….…….. 47 Acronyms and Abbreviations in Chapter 2 …………………….....……… 54 3. Designing of Microstrip Devices Using the FDTD Method ……..……..… 57 3.1. Introduction …………………………………………………….……. 57 3.2. Dispersion Effects …………………..………………………….……. 59 3.3. FDTD Analysis of Different Types of Microstrip Devices ….………. 60 3.3.1. Linear Low Impedance Microstrip Section ………….…….. 60 3.3.2. Gap End Coupled Linear Resonator ………………….…….. 62 3.3.3. Meander Lines ………………………………………….….. 63 3.3.4. Dual Mode Filters ………………………………………….. 66 v RF and Microwave Design Methods for Mobile Communication 3.4. Non-Homogeneous PML …………............………………………….. 69 3.5. FDTD Signal Estimation Technique ………………………………… 73 3.5.1. Signal Estimation for Meander Loop Dual Mode Filter Design ………………………………………………... 74 3.5.2. Signal Estimation for FDTD Analysis of Forward Coupled Filter ……………………………………………… 82 3.6. Microstrip Filter Design Using FDTD and Neural Networks ….……. 87 3.7. Chapter Summary …….…..………………………………….………. 93 References ……………………………………………………….....…….. 94 Acronyms and Abbreviations and Notations in Chapter 3 …………...…… 96 4. New Microstrip Filter Design …………………….…………………......…… 97 4.1. Introduction ………………………………………………….....…….