Thomas B.A. Senior

Thomas B. A. Senior has earned an international reputation for his work in scattering and electromagnetics. He has made fundamental contributions to the knowledge of electromagnetic and acoustic scattering and to the development of analytic and numerical techniques applicable at low, resonant and high frequencies. The early research was motivated by the desire to detect V2 missiles, first launched in WWII.

Senior was born in Yorkshire, England, on June 26, 1928. He received his MSc and PhD degrees in Applied Mathematics from Manchester and Cambridge Universities in 1950 and 1954, respectively. He spent five years as a Senior Scientific Officer at the Radar Research and Development Establishment in Malvern, during which time Prof. Keeve (Kip) Siegel began to visit him to consult on ongoing research at Willow Run. He was offered and accepted a position as Research Scientist to continue this work in the Department of Electrical and Computer Engineering in 1957. He received a special visa basd on a specific national scientific need, something that is still quite rare. He was appointed Professor in 1969.

Prof. Senior held a variety of leadership positions in the department. After serving as Acting Chair of the EECS Department during the calendar year 1987, he served as Associate Chair of the Electrical Science and Engineering Division and Associate Chair for Academic Affairs for the entire department until his retirement in 1998. Prior to his departmental leadership positions, he served as associate director (1962-74) and director (1974-87) of the RADLAB, where he carried out his research.

Prof. Senior has performed pioneering work in radar cross section (RCS) control, a measurement of how detectable on object is by radar. The research was initially motivated by the development of the V2 rocket in WWII. This was the first guided ballistic missile that could not be detected in advance (unlike its predecessor, the buzz bomb, which could be heard from long distances).

In the 1960s, Senior’s specific research turned to the detection of stealth aircraft rather than missiles. He created many of the analytical tools needed to predict how RCS reduction can be accomplished using shaping and radar-absorbing materials. In particular, he demonstrated how radar-absorbing coatings, smooth surfaces and body angles designed to scatter radar waves away from a receiver enable a low RCS. His research directly impacted the design of stealth aircraft in the U.S.

During the 1970s, Senior and his group were the first to recognize how large wind turbines can cause interference to electromagnetic systems, such as television. In fact, his research proved that the wind turbines installed on Block Island were negatively impacting television reception for residents of Rhode Island, leading to the U.S. government providing cable to every resident in the state. Back then, the turbines were made of metal which dramatically increased the interference. Senior and his team developed procedures that are now part of all environmental assessments of wind turbines.

During his career, Prof. Senior authored or co-authored three books. The first, Electromagnetic and Acoustic Scattering by Simple Shapes, was a foundational work that emerged from Willow Run research on the radar detection of aircraft and missiles. The other two were Mathematical Methods in Electrical Engineering and Approximate Boundary Conditions in Electromagnetics. He also contributed to other books, and authored more than 250 refereed journal articles and over 250 technical reports.

Prof. Senior directed the RADLAB at a time when military research, especially classified, on campus was a target for student activists. In 1983, 26 students staged the first of several lab sit-ins in protest of the university’s involvement in military research. Called the Progressive Student Network, the members managed to slow operations in Senior’s group for several days. A counter-protest group, naming themselves the Nuclear Saints of America, eventually converged on the lab as well, intent on resuming its research activities uninterrupted and “cleansing the lab from evil forces.”

The protests ended without fuss in Senior’s lab, though the activists continued their movement for a time in the lab of Prof. George Haddad. Despite the targeting of the department by the protestors, there was, in fact, no nuclear research and no direct weapons research being conducted in ECE. However, there were indirect links – as there will always be in the development of new technology, especially when funded by the Department of Defense.

Prof. Senior was appointed Arthur F. Thurnau Professor in 1991, an honor bestowed on the best University educators. He also received the CoE Teaching Excellence Award, the University of Michigan Teaching Excellence Award, the Eta Kappa Nu Award Teacher of the Year Award for two years in a row, and the Tau Beta Pi Outstanding Faculty Award.

When the EECS Department was formed in 1984 out of the previous ECE Department, the Computer, Information and Control Engineering (CICE) graduate program, and the Department of Computer and Communication Sciences (CCS), he was responsible for completely revamping the course numbers and selections for the department.

In addition to his numerous teaching awards, he received the CoE Research Excellence Award, the CoE Stephen S. Atwood Award, the IEEE Millennium Medal, the IEEE AP-S Distinguished Achievement Award, the URSI van der Pol Gold Medal, and the IEEE Electromagnetics Award.

Prof. Senior was active in the International Union for Radio Science (URSI) for almost 50 years. He was an Associate Editor and later Editor of “Radio Science” (then an URSI journal) from 1970 to 1979, and Secretary then Chair of USNC/URSI from 1979 through 1984. He was Vice Chair then Chair of URSI Commission B, 1987-1992, and Vice President then President of URSI itself from 1993-1999. He has also served on numerous URSI Committees, and wrote a history of the early years of URSI.

Senior retired as Emeritus Professor in 1998. He continued research in the RADLAB for a number of years, and wrote a history of the RADLAB and a history of the EECS Department since 1970.

Resources and Further Reading

IEEE Xplore: “Thomas B.A. Senior Wins the 2010 IEEE Electromagnetics Award”
Thomas Senior on the University of Michigan Faculty History Project
The Department of Electrical Engineering and Computer Science: A Brief Overview (1970 – 2010), by Thomas B.A. Senior
Radlab History, by Thomas B.A. Senior