The February 2006 meeting of the Dallas IEEE/EMC Society was held at the Holiday Inn Select, in Richardson, Texas, on February 21st.

An opportunity for networking was provided while refreshments were served from 6 to 7 PM, following which, the meeting was called to order by Bill Paschetag, chapter chairman. Attendees introduced themselves and Bill discussed sponsorship to help offset the cost of future meetings and the EMC chapter website.

The guest speaker for the February EMC meeting was EMC Society Distinguished Lecturer Dr. Christopher Holloway, NIST, Boulder, Colorado. Dr. Holloway is a member of Commission A of the International Union of Radio Science, an Associate Editor for the IEEE Transactions on Electromagnetic Compatibility and chairman for the Technical Committee on Computational Electromagnetics (TC-9) of the IEEE Electromagnetic Compatibility Society. He spoke on two topics that he is working on at NIST – first, on double-negative materials, controllable surfaces, and a new class of metamaterials, and second, on propagation and detection of RF signals before, during and after a building implosion.

There were 19 attendees, including 13 IEEE members and 6 non-members.

Refreshments for the meeting were provided by the Chapter.

The door prize, a $25 gift certificate to Appleby’s, was won by Steve Chenoweth.

The meeting adjourned at 9:30 PM. The next EMC chapter meeting will be held on March 21st, 2006 at the Richardson Radisson Hotel.

Submitted by Anthony Denton and Bill Paschetag

Program Summary - Topic 1: A Discussion on Double Negative Materials, Transition Boundary Conditions, Controllable Surfaces, and Design of a New Class of Metamaterials

In recent years, there has been a great deal of attention directed towards metamaterials (i.e., engineered or man-made materials). In the context of electromagnetics, examples of these are artificial dielectrics, photonic bandgap structures, and frequency-selective surfaces. More specifically and recently there have been studies on the properties and potential applications of double negative (DNG) materials. DNG materials are a class of metamaterials, also known as negative-index materials, backward media (BW), or left-handed materials, for which the effective permittivity and effective permeability are simultaneously negative. This class of metamaterials has a wide range of potential applications in electromagnetics (EM) and electromagnetic compatibility (EMC) including: (1) shielding materials, (2) low-reflection materials, (3) substrate materials, (4) antenna applications, (5) electronic switches, (6) the so-called perfect lens, and (7) clocking objects.

We show that the effective permeability and permittivity of composite medium consisting of insulating magneto-dielectric spherical particles embedded in a background can be simultaneously negative for wavelengths where the spherical inclusions are resonant to form a DNG material. The theoretical results presented here show that composite media having much simpler structure than those recently reported in the literature can exhibit negative permeability and permittivity over significant bandwidths.

Metamaterials are commonly engineered by arranging a set of scatterers embedded throughout a region of space in a specific pattern so as to achieve some desirable bulk behavior of the material. This concept can be extended by judiciously placing scatterers in a two-dimensional pattern at a surface or interface. This surface version of a metamaterial has been given the name metafilm. More specifically, a metafilm is a surface distribution of electrically small scatterers characterized by electric and magnetic polarizability densities. Here will present generalized sheet transition conditions (GSTCs) for the average electromagnetic fields across a metafilm where it is shown that the coefficients in the GSTC are related to the electric and magnetic polarizability densities of the scatterers on the interface. The transmission and reflection properties of a metafilm are presented where it is shown that the transmission and reflection coefficients are found to be functions of the electric and magnetic polarization densities. It is shown that the reflection and transmission coefficients can be controlled by changing the electric and magnetic polarizabilities in order to develop a “smart” or controllable surface. Finally, we introduce a metafilm composed of spherical magneto-dielectric particles for achieving a controllable surface.

Program Summary - Topic 2: Propagation and Detection of Signals Before, During, and After a Building Implosion

The National Institute of Standards and Technology (NIST) is currently involved with a project related to homeland security where communications problems for first-responders (firefighters and police) in disaster situations (i.e., collapsed buildings) is investigated. Also, various schemes are investigated for locating firefighters and civilians who may have portable radios or cell phones and are trapped in voids in the collapsed building.

Part of this work utilizes buildings that are scheduled to be imploded. RF transmitters which transmit at frequencies near public safety and cell phone bands (approximately 50 MHz, 150 MHz, 250 MHz, 400 MHz, 900 MHz, and 2 GHz) are placed in various locations in the building. The received RF signals are measured before, during, and after the building is imploded. Once the building is down, various location schemes are investigated which involve searching with directional antennas and connecting instruments to some of the metal debris located on the perimeter of the collapsed building.

Three such sets of experiments have been completed, one in a 13 story apartment complex in New Orleans, a second one at the Veterans Stadium in Philadelphia, and a third one at the Convention Center in Washington, DC.

This presentation summarized the experiments in these three locations with a multi-media presentation of photos, videos, and news clips of the building implosion. Also, primary results of the data that was collected will be presented and some of the interesting propagation effects observed will be discussed.

Our Speaker:  Dr. Christopher Holloway received his BS degree in Engineering from the University of Tennessee and MS and PhD degrees in Electrical Engineering from the University of Colorado. He is also on the Graduate Faculty at the University of Colorado.

Prior to 1992, Dr. Holloway worked as a staff scientist with Electro Magnetic Applications, Inc., in Lakewood, Colorado where his responsibilities included theoretical analysis and finite-difference time-domain modeling of various electromagnetic problems. From the fall of 1992 to 1994, he was with the National Center for Atmospheric Research (NCAR) in Boulder, Colorado where his duties included wave propagation modeling, signal processing studies, and radar systems design. From 1994 to 2000, he was with the Institute for Telecommunication Sciences (ITS) at the U.S. Department of Commerce in Boulder where he was involved in wave propagation studies. Since 2000, he has been with the National Institute of Standards and Technology (NIST) in Boulder where he works on electromagnetic theory. His research interests include electromagnetic field theory, wave propagation, guided wave structures, remote sensing, numerical methods, and EMC/EMI issues.

Dr. Holloway holds U.S. Patents on electromagnetic absorbing materials, radar systems and antennas for atmospheric radars and also has authored over 125 technical publications. He was awarded the 1999 Department of Commerce Silver Medal for his work in electromagnetic theory and the 1998 Department of Commerce Bronze Medal for his work on printed circuit boards.

He is a member of Commission A of the International Union of Radio Science, a Senior Member of the IEEE, an Associate Editor for the IEEE Transactions on Electromagnetic Compatibility, the chairman for the Technical Committee on Computational Electromagnetics (TC-9) of the IEEE EMC Society, and is presently serving as a Distinguished Lecturer for the IEEE EMC Society.