APWC2000 - Short Courses
Microstrip Antennas
Dr. Rod Waterhouse
Microstrip or printed antennas are being considered/used in a variety of communication systems due to their many advantages, including low profile, light weight and ease of integration with microwave and photonic devices. It is due to these features that has seen versions of the microstrip patch antenna used for applications ranging from satellite main mission antennas to small handset terminal antennas for mobile communications. However, despite the microstrip patch starting to be incorporated into main stream applications there are still several shorting comings of the conventional form of this printed antenna that has hindered its development. These include its relatively small bandwidth and the excitation of surface waves. Over the past decade or so researchers throughout the world have focused on means of alleviating these problematic characteristics with varying degrees of success. In particular, looking at means of improving the impedance bandwidth, reducing the size of the printed conductor, efficiently integrating the antenna with MMIC and OEIC technologies and also enhancing the scan performance of large arrays of microstrip patches.
In this course we will cover a number of topics that are fundamental to developing an understanding of microstrip patch antennas and the role that they play in developing wireless communication systems. These include: (1) the general characteristics of microstrip patches; (2) a comparison of the excitation/feeding methods; (3) techniques to improve the impedance bandwidth; (4) methods to generate circular polarization; (5) methods to reduce the size of the patch conductor; (6) how to efficiently integrate these antennas with MMIC and OEIC technologies; (7) a comparison of array architectures; and (8) methods to design omni-directional printed antennas. Finally, if time permits, the design procedure for several cases will be presented.
Dr Rod Waterhouse received the degrees of Bachelor of Engineering (Hons), Masters of Engineering Science (Research) and PhD from the University of Queensland, Australia in 1987, 1990 and 1994, respectively. In 1994, he joined the Department of Communication and Electronic Engineering at the RMIT University, where he is currently a Senior Lecturer. His research interests include printed antennas, phased arrays, optically distributed wireless systems and photonic devices for microwave applications. He has published over 120 papers in these areas. In 2000 RMIT University became a member of the Australian Photonics Cooperative Research Centre of which he is a Key Researcher. Dr Waterhouse is the Chair of the IEEE Victorian MTTS/APS Chapter.
Practical Consideration in the design of Antennas for Wireless Communication
Dr. Naftali (Tuli) Herscovici
This short course will address specific topics related to the design and fabrication of antennas for wireless communication. In the first part, we will discuss the types of antennas used in this industry, as well as strategies for choosing the right antenna for a system. A short historical background will illustrate the evolution of the antenna industry from the military technology to the emerging commercial applications of the late 90s. The second part will focus on antennas used in the wireless communication industry: microstrip antennas and arrays, wire antennas and MMwave antennas. In the third part of the course we will design different types of antennas using an electromagnetic simulator (IE3D by Zeland Software) and compare the results with those obtained using different software packages: NECWINPro by Paragon Technology, The Antenna Optimizer and The Yagi Optimizer by Brian Beezley and The Antenna Radiation Pattern Software by Far Field Corp. We will conclude with an interactive design session.
Dr. Naftali Herscovici joined Spike Technology Inc. in January 1998 as its Chief Antenna Scientist. Dr. Herscovici has over 20 years of experience in the design of antennas in general and antennas for wireless communication in particular. He received his Ph.D. in Electrical Engineering from the University of Massachusetts at Amherst in 1992 and is the author of over 50 technical papers in various journal and conference publications.
In 1978, after gradating from the Israeli Technologic Institute (Technion) he was employed by the Israeli Navy as an Electronic Engineer. In 1982 he joined RAFAEL, the Research Institute of the Israeli Department of Defense, where he was employed as an antenna engineer. There he was in charge with the design and fabrication of a large variety of antennas for military systems. He also conducted research in the area of numerical electromagnetics.
In 1989 he joined the University of Massachusetts where he obtained his Ph.D. in 1992. During these years he acquired valuable experience in the design of microstrip antennas and arrays. He developed numerous new configurations, which were published in professional journals such as the IEEE Transactions on Antennas and Propagation and Microwave Journal.
In 1992 he joined Chu Associates as a Senior Project Engineer. There he was engaged in the design and fabrication of numerous antennas such as reflectors, dielectric polyrods and discone antennas.
In 1994 he joined Spears Associates as its Chief Scientist. Spears Associates, was one of the few companies in the world specializing in the field of communication systems for submarines. There, Dr. Herscovici developed antennas for the Multifunction Mast Antenna for Submarines. The multitude of communication tasks involved in a submarine mission together with the extraordinary space limitations present the antenna engineer with a unique design challenge. Spears Associates work was successful in finding an optimized solution to this problem whose main goal was the maximization of the number of simultaneous frequency bands of coverage. This Multifunction Mast Antenna was designed, built, and successfully tested and its first version is currently in operation in the US Navy.
In 1996 Naftali (Tuli) jointed Cushcraft Corporation, as Chief Scientist. Here he helped developing a full line of antenna products for wireless communications. Some of his designs are unique and one of them was awarded the Product of the Year Prize by the Wireless Design Magazine for 1997.
For more details visit his website at www.anteg.net
Electromagnetic Simulators - IE3D and Fidelity by Zeland Software
Dr. Jian Zheng
IE3D and FIDELITY are general purpose electromagnetic simulators. The IE3D is based upon moment method solving the current distribution on planar and 3D metallic structures in layered dielectric environment. It is very suitable for the design of printed antennas (patch antennas, printed dipoles), 3D wire antennas (dipoles, conical helix and cylindrical helix antennas), inverted-F antennas and other wireless antennas, as well as RF circuits. The IE3D has extremely powerful and flexible graphic interface and simulation engine allowing users to build and simulate complicated structures in a short time. It also has a built-in robust genetic optimizer for efficient electromagnetic optimization. It helps users to achieve optimum performance for their antennas and RF circuits. Typical examples are antenna optimization for wide bandwidth and filter optimization for lowest insertion loss in the pass band.
FIDELITY is a FDTD based time domain simulator. It is solving the 3D field distribution surrounding an antenna (or circuit) structure. It is most suitable for general 3D metallic and dielectric structures. Due to its full 3D features, it can be used to solve problems such as dielectric resonators, dielectric antennas, horn antennas, waveguide structures and connectors. It is also applicable to many different kinds of antenna and RF applications. FIDELITY performs a simulation in the time marching style. It does not require any matrix inversion. It is very suitable for electrically large 3D structures. The most important feature of the FIDELITY is that it provides excellent near field and SAR visualization. The SAR (specific absorbing rate) is a major measure on the electromagnetic bio-medical effects on human body. The FIDELITY allows users to predict E-field, H-field, Poynting Vector, the maximum SAR and average SAR and visualize them in different forms.
The courses are suggested to all level IE3D and FIDELITY users. It is also suitable to those engineers who want to get some knowledge on how electromagnetic simulators can be applied to their practical design.
Modern Topics in Personal Communications Antennas:
Design and Analysis Techniques including Human Interaction
Prof. Yahya Rahmat-Samii
The introduction of personal communications technology has resulted in a widespread awareness of the critical role wireless services play in today’s communications-centered marketplace. Antennas play a paramount role in an optimal design of the hand-held units used in these services. Clearly in designing these antennas the electromagnetic interaction among the antenna, the hand-held unit, and the human operator is an important factor to be considered. Additionally, diverse requirements for the terrestrial and satellite applications necessitate in-depth evaluations of various antenna configurations including diversity considerations. In this presentation the following topics will be addressed:
(a) The modern age of personal communication,
(b) Advanced computational and optimizations techniques (FDTD, MoM, EEM, GA, etc.)
(c) Monopole, PIFA and others
(d) Spherical and MRI head models
(e) Head and hand interactions and SAR characterizations
(f) Measured results and comparative studies among various computational techniques
(g) Terrestrial and satellite applications
(h) Miniaturization and reduced interaction designs for antennas
Smart Antennas
Prof. Christos Christodoulou and Dr. Ahmed EL Zooghby
Smart antennas have recently received increasing interest in improving the performance of wireless radio systems. These systems of antennas include a large number of techniques that attempt to enhance the received signal, suppress all interfering signals, and increase capacity, in general. This short course will provide an overview of the current state of research in the area of smart antennas and describe how they can be used in wireless systems. A basic model for determining the angle of arrival for incoming signals, the appropriate antenna beam-forming, and the adaptive algorithms that are currently used for array processing will be provided. Moreover, it will be explained how smart antennas, with spatial processing, can provide substantial additional improvement in the capacity, number of cells, coverage, handoff overhead reduction in TDMA and CDMA digital communication systems.
Topics:
Prof. Christos G. Christodoulou: received the B.Sc. degree in physics and math from the American University of Cairo in 1979, and the M.S. and Ph.D. degrees in Electrical Engineering from North Carolina State University, Raleigh, in 1981 and 1985, respectively. He served as a faculty member in the University of Central Florida, Orlando, from 1985 to 1998, where he received numerous teaching and research awards. In 1999, he joined the faculty of the Electrical and Computer Engineering Department of the University of New Mexico, Albuquerque as a Chair. In 1991 he was selected as the AP/MTT Engineer of the year (Orlando Section). He is a senior member of IEEE and a member of URSI (Commission B). He served as the general Chair of the IEEE Antennas and Propagation Society/URSI 1999 Symposium in Orlando, Florida. He is the co-chair of the IEEE 2000 Symposium on Antennas and Propagation for wireless communications, Waltham, MA and the Chair for the IEEE 2001 Symposium on Antennas and Propagation for wireless communications, Albuquerque, NM. He has published over 140 papers in journals and conferences. He also has two patents. He is currently, the co-editor for a column on "Wireless Communications" for the IEEE AP Magazine. His research interests are in the areas of modeling of electromagnetic systems, neural network applications in electromagnetics, and smart antennas
UHF Propagation for Modern Wireless Systems
Prof. Henry L. Bertoni
Modern wireless systems employ spatial re-use of the limited spectrum available in order to serve may subscribers. Spatial re-use places at odds the need for adequate coverage and the need to avoid interference from distant channels the re-use the spectrum. When treated in the context of the urban propagation environment, with its extremes of shadowing and multipath scattering, this competition between coverage and interference avoidance places strong demands on the knowledge and ingenuity of the system designer.
This tutorial will discuss the characteristics of the urban wireless channel. We will review the various manifestations of the multipath scattering for narrowband and broadband signals, including Raleigh and Rician fading, time delay spread, angle of arrival distribution and depolarization. We will discuss the causes leading to the log normal distribution of shadow loss, along with its implications for system design. Dependence of the average signal level on range R will be described for different antenna heights and propagation environments. Measurement based and theoretical models of the various phenomena will be discussed to give the practitioner both convenient engineering tools, as well as a conceptual basis for understanding and reasoning about propagation issues effecting wireless.
Prof. Henry L. Bertoni has been Department Head (1990-95) and Vice Provost for Graduate Studies (1995-96). He has a Visiting Fellow at the Department of Electrical and Electronic Engineering, University College, London (1992 - 1993), Sponsored by the Royal society and been a Summer Faculty Research Fellow (1993), USAF Rome Air Development Center, Hanscom, MA.
He received the PhD in Electrophysics (1967) and MS in Electrical Engineering (1962) from Polytechnic Institute of Brooklyn (now Polytechnic University), Brooklyn, New York and the BS in Electrical Engineering (1960) from Northwestern University, Evanston, Illinois.
Starting in the mid 1980's Professor Henry L. Bertoni has led a group in the study of UHF propagation in urban environments. They were the first to understand the mechanisms governing average signal strength for elevated base station antennas of cellular mobile radio (CMR). These results are the basis for the COST-231 model used throughout the world for installation of 1900 MHz GSM and PCS systems.
Later work treated propagation from the low base station and has been incorporated in the new standards developed by the Joint Technical Committee of the US PCS industry. They were the first to identify mechanisms leading to the slow fading observed in outdoor channels, and to explain its log normal statistics. A novel outdoor site specific ray tracing computer program, called the Vertical Plane Launch (VPL) method, was developed for microcell predictions in mixed building environments.
Research in outdoor propagation is continuing with a study of the effects of foliage and terrain, as well as sources of multipath at the base station for fixed wireless systems.
The group has also studied characteristics of the indoor radio channel resulting both theoretic and experimentally. These studies have led ray tracing codes predicting indoor propagation
Over 40 papers in journals and conference proceedings, including an invited survey paper in the Proceedings of the IEEE come out of these studies. One paper was given the 1993 Neal Shepherd Best Propagation Paper Award of the IEEE VT Society
Dr. Bertoni is a Fellow of the IEEE, and a member of the International Scientific Radio Union and the New York Academy of Science. He has served as Chairman of the Technical Committee on Personal Communications of the IEEE Communications Society, as Chairman of the Hoover Medal Board of Award, and was on the ADCOM of the IEEE Ultrasonics, Ferroelectric and Frequency Control Society.