| Present: | Dean, School of Engineering and Professor of Electrical Engineering, University of Mississippi |
| 1996-2000t: | Chairman & LaPierre Professor, Electrical Engineering, University of Missouri-Columbia |
| 1988-1995: | Professor and Chairman, Electrical Engineering, The University of Toledo, Toledo, Ohio Summers 86&87:ASEE-NASA Summer Faculty Research Fellow at NASA Lewis Res. Center, Cleveland, Ohio |
| 1985-1988: | Professor of Electrical Engineering, University of Akron, Akron, Ohio |
| 1984-1985: | Founding Head, Department of Electronic Engineering, City University of Hong Kong |
| Summer 75: | Visiting Researcher, Plasma Engineering Laboratory, UCLA |
| 1973-1984: | Department of Electronics, The Chinese University of Hong Kong. Lecturer: 1973-77; Senior Lecturer: 1977-83; Reader: 1984 |
| 1972-1973: | National Research Council Senior Resident Research Associate at the National Oceanic and Atmospheric Administration, Boulder, Colorado |
| 1968-1969: | Visiting Scientist, National Center for Atmospheric Research, Boulder, Colorado (on leave from Catholic University) |
| 1967-1972: | Department of Space Science and Applied Physics, The Catholic University of America, Washington, D. C. Assistant Professor: 1967-69; Associate Professor: 1969-72 |
| 1966-1967: | Postdoctoral Research Physicist, Department of Applied Electrophysics, University of California, San Diego |