A Pulse on the Problem

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Dec. 1, 2012

A Pulse on the Problem

Microwave engineer at Trinity University touches many disciplines in his research

Joshua Schwartz

 SAN ANTONIO - Joshua Schwartz is a microwave engineer, but don't bother calling him if your fast-heating oven goes on the fritz. Schwartz, an assistant professor of engineering science at Trinity University, is contributing to international research on the use of microwave imaging to detect breast cancer and, with the help of a Trinity undergraduate, is figuring out ways to identify fluids using only the tiniest amounts without touching or destroying them. The latter technique could yield exciting chemical or biomedical applications or even aid in crime scene analysis.

"In my lab is the world's smallest microwave oven," Schwartz said, "with a chamber that barely holds a few microliters of fluid." The device is connected to a vector network analyzer, which he uses as a tool for characterizing microfluids. Schwartz and his students are testing droplets of ordinary substances like alcohol and water, but the unique aspect of his work is that the testing does not destroy the sample of material. He uses a syringe to inject the liquid, activates the electromagnetic waves, and is able to evaluate what the fluid is by observing its response to a range of frequencies. Such a process could reveal whether a red droplet found in a kitchen murder is blood or ketchup, for example, without altering its chemical composition or allowing a limited sample to evaporate.

In current practice, engineers no longer work in a vacuum but reach out to other departments and disciplines. "There was a time when engineers could invent something to change the world in their garage. Invention is now done by large teams of well-funded researchers. This is the current reality of R&D (research and development,)" Schwartz said, adding that it hasn't stopped him from setting up Trinity's first microwave-oriented lab on his own.

Joshua SchwartzSchwartz seemed destined to take engineering science in a multidisciplinary direction. As a graduate student at McGill University in his hometown of Montreal, Canada, he worked in a lab for photonics, the study of light and fiber optics. "I was a microwave guy sitting in a room filled with laser lovers." But he drew upon their ideas, applying them to the microwave world, which, he says, is "just a differently-sized frequency of radiation that plays by many of the same rules." At Trinity, he teaches a new course called "High Frequency Electromagnetics" - so named because he didn't think anyone would sign up for "microwave engineering" - that is cross-listed with physics. In fact, much of Schwartz's work touches other disciplines. He speaks of measuring the unique properties of the fluids passing through the "world's smallest microwave," including how much radiation it absorbs and how much it slows down what passes through or reflects back. "Most people just know that microwaves are useful for heating," but Schwartz adds that he is considering exploring that aspect as well, for example by using microwaves to heat up a chemical reaction while measuring its changing properties in real time.

It is to the field of biology and medical instrumentation where Schwartz recently traveled, to search for better ways to detect breast cancer. The idea is to establish a baseline image of a patient's breast tissues and provide a possible early detection system. He teamed with researchers from McGill to shape electromagnetic pulses launched into lab-made phantom breasts containing a mass similar to a tumor. Schwartz improved the image so it could provide a higher resolution look at the tissues rather than a broad slice lacking detail. If, over time, successive images show a larger and potentially growing tissue mass in a patient, a medical professional would be alerted. "With this method, there's no compression (as in a mammogram) and the microwaves are harmless," Schwartz said, adding that the radiation from the microwaves involved is much less than from an ordinary cell phone. The team includes researchers from Canada and Spain, and Schwartz said the next step is clinical trials and a search for equipment that is compact, convenient, and affordable.

Spending a summer studying with Schwartz in Canada was a highlight for engineering science student Mohsin Rahim, a candidate for graduation in December 2013. The son of a doctor, Rahim was expected to prepare for a medical career but an unpleasant hospital stay as a child left him thinking otherwise. Besides, he said he is drawn to the challenge of building projects that can solve a real-world problem. "The exciting part for engineers is that what we learn in class, we can apply it," he said, adding that working with Schwartz has offered many opportunities to solve many problems.

Courses Taught

  • Circuit Analysis Lab
  • Electronics I
  • Electronics I Lab
  • High-Frequency Electromagnetics

Select Publications

  • J. D. Schwartz, A. Santorelli, M. Rahim and P. J. Roche, "Microwave permittivity measurement of microfluids in microstrip technology," in progress.
  • A. Santorelli, M. Chudzik, E. Kirshin, E. Porter, A. Lujambio, I. Arnedo, M. Popovic and J. D. Schwartz, "Experimental demonstration of pulse shaping for time-domain microwave breast imaging," Progress in Electromagnetics Research (PIER), v. 133, pp. 309-329, 2013.
  • J. D. Schwartz and A. Ater Kranov, "Introducing contemporary issues to engineering students: A case study module," American Society for Engineering Education (ASEE), Annual Conference and Exposition, San Antonio, Texas, June 2012.
  • J. D. Schwartz, Q. Zhuge, J. Azaña and D. V. Plant, "1-D Uniform and chirped electromagnetic bandgap structures in substrate integrated waveguides at 60 GHz," Microwave and Optical Tech. Lett., v. 54 (3), pp. 735-7, March 2012.
  • J. D. Schwartz, J. Azaña and D. V. Plant, "A fully-electronic system for the time magnification of GHz electrical signals," IEEE Transactions on Microwave Theory and Techniques, v.55, n.2, pp. 327-34, Feb. 2007. Winner of the 2009 IEEE MTT-S Microwave Prize.

-- Susie P. Gonzalez