STEM Shoutout: Dr. Francesca Cavallo
Professor awarded grant for work on vacuum electronic devices
Dr. Francesca Cavallo, an assistant professor of electrical and computer engineering at UNM with an appointment at the Center for High Technology Materials, has been awarded a three-year, $860,000 grant from the Airforce Office of Scientific Research to establish a radical new concept for scaling the operation of traveling wave tubes (TWTs) beyond the microwaves and into THz frequencies.
“TWTs are vacuum electronic devices that touch our lives every day. They make satellite communications possible because of their exceptional on-orbit reliability and high-power efficiency. TWTs also enable television broadcasting and modern aviation radar systems,” Cavallo said.
“No solid-state device can provide as much power as a TWT at wave frequencies. Nevertheless, application of these devices at frequencies beyond the microwaves is limited by a number of challenges that relate to fabricating devices with the required micro- and nanoscale dimensions to amplify THz radiation.”
As part of the work, “we have invented a way to replace the wire helix that is the central feature of a TWT,” Cavallo said. “We are thus able to make micro- and nanoscale diameter structures that are additionally self-winding and mass-producible. We have further developed new ways of testing and qualifying these structures that are potentially more rapid than conventional ones. The upshot is that we can market these helical waveguides to customers who are building high- power, high-frequency amplifiers.”
The innovative approach of this work to modeling, realization, and testing of extremely small helical slow-wave structures will provide the DoD and scientific community with a transformative route and knowledge base to develop more advanced travelling-wave tubes (TWTs), ones that scale up in frequency in a manner that currently planned or in-progress approaches cannot.
“We are paving the way to more affordable and low-form factor amplifiers of THz waves” she said.
“These devices will potentially enable applications and discoveries of wide diversity in materials science, warfare, wireless communications, high-frequency electromagnetics, astrophysics, and biomedical sciences.”