2007 IEEE Radio and Wireless Symposium

Abstract: In recent years, there has been a considerable amount of interest in development of electrically small and low-profile multifunction/reconfigurable antenna elements and arrays for both civilian and defense applications. In particular, antenna miniaturization has been the subject of intense investigation over the past decade with the significant commercial growth of wireless devices as well as the emergence of electronic intelligence and digital battlefield, which require electrically small antennas operating in VHF and UHF bands. In addition, extensive efforts are currently underway to develop universal wireless receivers that necessitate design of multi-band, multi-service, and multi-standards antennas. These requirements provide challenging problems for the antenna engineer in optimization and design of the future generation of electrically small and reconfigurable antenna systems.

This short course begins with an overview of the basic theory and concepts associated with electrically small antennas. The presentation provides an understanding of antenna performance limitations in terms of impedance, radiation patterns, bandwidth, efficiency, and quality factor. The presentation continues with a discussion of recent advances in the field of electrically small antenna design. Techniques discussed include dielectric loading, impedance loading, linear loading, top-loading, folded configurations, Genetic Algorithm optimization, etc. The relationship between the antenna’s performance characteristics and its physical properties are discussed. This segment concludes with a discussion of recent advances in the design of low profile, conformal and integrated device antennas.

In the second part of the short course, the concept of Reactive Impedance Surface (RIS) as a substrate for planar antennas, that can miniaturize the size and significantly enhance both the bandwidth and the radiation characteristics of an antenna above such substrate, will be presented. A RIS can be tuned anywhere between Perfectly Electric and Magnetic Conductor (PEC and PMC) surfaces offering the unique property to achieve the optimal bandwidth and miniaturization factor. The concept of artificial magnetism using embedded circuit metamaterials will also presented for both miniaturization of antennas. Design examples using both analytical and numerical simulation verified by experimental results will be presented.

In the third part, the concepts of space-filling curves (SFC), such as Hilbert and Peano curves, will be introduced and their applications in design of self-resonant electrically small antennas and high impedance ground planes will be detailed. These curves offer an attractive technique for antenna miniaturization, since a structure of this shape can be made of an electrically long metallic wire compacted within a very small footprint. The presentation will include applications of SFCs in design of wideband top-loaded monopoles, dual-band PIFA for ISM bands, RFID tags, and EBG surfaces. Design examples include both simulated and experimental results.

In the last part, we discuss the reconfigurable antennas, which would have great potential to provide such versatility in a compact, low cost, and high performance structure. However, they have certain limitations, which include the presence of higher order resonances (spurious resonances) and the need to simultaneously serve multiple services at the same time, but these hurdles can be circumvented. We will evaluate the different design options, present some examples of reconfigurable wireless antennas, and elaborate on their limitations.

Background required for this short course includes: i) Undergraduate-level antenna theory and familiarity with basic antenna terminologies. ii) Undergraduate-level microwave theory and familiarity with impedance matching techniques.

Instructors:

Dr. Steve Best, Mitre Corporation Fundamentals of electrically small antennas and their optimal design
Prof. Kamal Sarabandi, University of Michigan, Ann Arbor, MI Antenna miniaturization using EBG and reactive Surfaces
Prof. Ahmad Hoorfar, Villanova University, Villanova, PA Antenna miniaturization using space-filling curves
Prof. Aly Fathy, University of Tennessee, Knoxville, TN Reconfigurable antennas

SCFRI2: Spectrum Policy and Regulation for the R&D Wireless Engineer
Friday 8:30AM – 12:30 PM

Abstract: Spectrum policy and regulatory issues are just as real for the designer of innovative wireless systems as Maxwell's Equations, although they sometimes can be changed given early recognition of problems and adequate lead time. This course will be taught by an engineer and a lawyer who both have long experience in spectrum policy issues and by a manager of an EMC test firm/telecommunications certification body (TCB). The course will show how to see if a new wireless technology raises significant issues under current regulations or not, estimating the complexity of possible regulatory issues that might impact practical use of the technology, and evaluating options for addressing policy issues in parallel with development. It will also address the importance of designing compliance into new technology just as one would design reliability into a product and not waiting until the eve of production. Finally, it will review the final step of how to get a new wireless system that complies with regulations approved for sale in various markets. It will also discuss ways to participate in the regulatory process and identifying when outside specialized help might be needed.

The first part of the course will review the basic sources of technical regulations for wireless technologies, their original intentions, and trends in present day approaches to policy development. The focus will be on US regulation with examples from other countries mentioned for comparison. Areas covered will be frequency allocations, emission standards, and marketing regulations. Future issues such as cognitive radios, the ongoing controversy of unlicensed vs. licensed use, and public safety interoperability issues will be covered.

The second part of the course will cover what you need to know but missed because you didn't go to law school: How regulations are made. Opportunities to participate in the development of regulations for wireless technologies. How to decide when you may need professional help in participating in policy development. When waivers can be a promising approach for new technologies that generally, but not completely, comply with existing regulations.

The final part of the course deals with wireless systems that are designed to meet existing regulations but must show compliance before they can be marketed. The importance of considering EMC issues throughout system design will be discussed as well as sources for such information. Then options for EMC testing and the procedures for marketing authorization for various countries will be discussed.

Basic knowledge of wireless technology and interest in learning about the broader context of regulatory issues will meet the background required for this short course.

Instructors:

Dr. Michael Marcus, Marcus Spectrum Solutions

An Introduction to Spectrum Allocations and Wireless Technology Regulations for Engineers