The 18th International Symposium on Electrets (ISE 18)
Virtual Conference, 24-28 September 2021, Shanghai, China
Special for Sessler and West

First patent on foil electret microphone by G. M. Sessler and J. E. West

Gerhard M. Sessler

Gerhard M. Sessler (born 15 February 1931 in Rosenfeld, Baden-Württemberg, Germany) is a German inventor and scientist. He is Professor Emeritus at the Department of Electrical Engineering and Information Technology of the Technische Universität Darmstadt.

Together with James E. West, he co-invented the foil electric microphone at Bell Laboratories in 1962 and together with Dietmar Hohm the silicon microphone in 1983.

From 1950 to1959, Sessler studied physics at Universities of Freiburg, Munich, and Göttingen. He received his diploma in 1957 and his Ph.D. from the University of Göttingen in 1959. After working in the United States at Bell Labs until 1975, he returned to the academia in Germany. From 1975 to 2000, he worked as a professor of electrical engineering at the Department of Electrical Engineering and Information Technology of the Technische Universität Darmstadt where he invented the silicon microphone. Since 1999, Sessler is Professor Emeritus. At age 90 in 2021, he is still an active scientist working on flexible ferroelectrets and energy harvesters.

He holds over 100 international patents, among them 18 US-patents. The first one, US 3,118,022, with James E. West, was issued on 14 January 1964.

Sessler is the author/editor of several books on electrets and acoustics. In 2014, together with Ning Xiang, he co-edited a memorial book on Manfred R. Schroeder published by Springer. Furthermore, he is well known for his over 300 scientific papers in prestigious international magazines and journals.


•Fellow of the Acoustical Society of America, 1964

•Fellow of the IEEE, 1976

•Fellow of the American Physical Society, 1991

•George R. Stibitz Trophy of AT&T, 1993

•Helmholtz-medal of the Deutsche Gesellschaft für Akustik, 1993

•Silver Helmholtz-Rayleigh-medal of the Acoustical Society of America, 1997

•Induction into the National Inventors Hall of Fame, 1999

•Technology Award of the Eduard Rhein Foundation, 2007

•Honorary doctorate from the National Academy of Sciences of Belarus, 2010

•Benjamin Franklin Medal in Electrical Engineering of The Franklin Institute, with James E. West, 2010

•IEEE/RSE James Clerk Maxwell Medal, 2012

•Gold Medal of the Acoustical Society of America, 2015

James E. West

James Edward Maceo West (born 10 February 1931 in Farmville, Prince Edward County, Virginia) is an American inventor and acoustician. He holds over 250 foreign and U.S. patents for the production and design of microphones and techniques for creating polymer foil electrets.

West received a bachelor's degree in Physics from Temple University in 1957. In 2001, West retired from Lucent Technologies after a distinguished 40-year career at Bell Laboratories where he received the organization's highest honor, being named a Bell Laboratories Fellow. West then joined the faculty of the Whiting School at Johns Hopkins University where he is currently a Professor in the Department of Electrical and Computer Engineering. In 2007, West received an honorary doctorate from NJIT.

Along with Gerhard Sessler, West invented the foil electret microphone in 1962 while developing instruments for human hearing research. Compared to the previous condenser microphones, the electret microphone has higher capacitance and does not require a DC bias. West and Sessler optimized the mechanical and surface parameters of the system. Nearly 90 percent of more than two billion microphones produced annually are based on the principles of the foil-electret and are used in everyday items such as telephones, camcorders, hearing aids, baby monitors, and audio recording devices among others. West measured the acoustics of Philharmonic Hall in New York City. Recently, West teamed with Ilene Busch-Vishniac and studied the acoustic environment of hospitals showing that hospitals are in general too loud and that the noise levels affect staff and patients. Dr. West has over 250 patents to his name. At age 90 in 2021, he is still an active inventor working on a device to detect pneumonia in infant lungs.

Dr. West is the recipient of the National Medal of Technology and Innovation, and in 2010, along with Gerhard M. Sessler, West was the recipient of The Franklin Institute's Benjamin Franklin Medal in Electrical Engineering. He is also an inductee to the National Inventors Hall of Fame and an elected member of the National Academy of Engineering. He is also the recipient of numerous other honors and awards.