Fritz E. Borgnis (December 24, 1906 – August 27, 1982) was a German applied physicist and electrical engineer, known for his contributions to microwave physics, guided waves and ultrasonic measurements for medical diagnostics.

After completing high school in Hamburg, he matriculated at the Technische Hochschule of Munich where he received a diploma in electrical engineering in 1929.

[2] He continued his academic career at the University of Graz followed by two years at the ETH Zurich from 1948 until 1950.

From 1957 until 1960, Borgnis acted as director of research at the Allgemeine Deutsche Philips Industrie in Hamburg.

From the early 1960s, Borgnis' projects at ETH dealt with measurements of flow in liquids using ultrasound.