Dr. Bernhard's Wireless Communications Research and New Laboratory

by Jennifer T. Bernhard

Portable wireless communication systems face a unique kind of interference from their local electromagnetic environments. These environments contain both scatterers, such as the chassis of the wireless equipment, and absorbers, such as users and their full coffee cups! These kinds of scatterers and absorbers may profoundly affect the performance of portable units for both high (cellular telephones) and low (LAN) tier applications, causing multipath interference, signal blockage, or general degradation of the communications connection. As a result, existing wireless systems designed for voice transmission will not provide adequate performance for the more demanding data and video transmission of the future.

My research seeks to improve the reliability of present and future wireless communication links through simulation and measurement of the local electromagnetic environments in which portable wireless units operate. My work investigates a variety of consumer-end wireless equipment, emphasizing the user and unit's chassis as parts of the electromagnetic subsystem. The results will characterize the conditions under which portable wireless systems are expected to perform reliably, facilitating improvements in antenna design and antenna placement on portable units. Additionally, I have been studying antenna diversity techniques and developing theoretical models for integrated microstrip antennas.

The renovation of laboratory space (as yet unnamed, suggestions welcome!) in Kingsbury 105BA has provided an ideal space for this work. Thanks are due to the ECE Department for agreeing to the renovations and to Frank Hludik, Adam Perkins, and Gene Filley for helping to get the space into shape. Over the past year, I've focused on the specification and acquisition of appropriate simulation and measurement facilities and equipment. For instance, the laboratory acquired an S-parameter test set for use with the Department's vector network analyzer, which will enable antenna input impedance measurements as well as other RF and microwave circuit measurements for my research, senior projects, graduate theses, and EE758 projects operating at frequencies up to 6 GHz. In the very near future the laboratory will also be acquiring a computer and FDTD (Finite Difference Time Domain) simulation software that will support many aspects of this research.

Currently, the lab is being inhabited by two NSF REU students, Carolyn Tousignant and Shawn Staker, who are doing their best to make it feel like home. They are both working on antenna designs for wireless communication systems that will be fabricated and measured in the lab. Next year, lab activities will focus on continuation of the research as well as assembly of measurement equipment for antenna radiation pattern measurements.