Electrical and Computer Engineering ETDs

Publication Date



A systematic study of high power backward wave oscillators (BWOs) was performed using the Sinus-6 repetitively-pulsed relativistic electron beam accelerator. Peak output power of up to 550 MW was measured in a frequency range of 9.2 to 9.8 GHz with pulse lengths up to 10 ns. The experimental results were compared with numerical simulations using TWOQUICK, a 2.5 D, relativistic, fully electromagnetic, particle-in-cell (PIC) code. It was observed that a significant increase in microwave efficiency can be obtained by using a BWO with a spatially varying coupling impedance instead of the traditional uniform distribution. Based on experiments using variations of a two stage nonuniform amplitude BWO in conjunction with TWOQUICK simulations, it was determined that the efficiency enhancement can be attributed to the prebunching of the electron beam.


Air Force Office of Scientific Research

Document Type




Degree Name

Electrical Engineering

Level of Degree


Department Name

Electrical and Computer Engineering

First Committee Member (Chair)

Ed Schamiloglu

Second Committee Member

Raymond W. Lemke

Third Committee Member

John Gahl

Third Advisor

Charles Fleddermann