  This paper focuses on the RF study of a C-band(5712MHz) BOC pulse compressor.
The operating principle of BOC is presented and the technical specifications
are determined. The main components of BOC such as the cavity, the matching
waveguide, the coupling slots and the tuning rings were numerically simulated
by 3-D codes software HFSS and CST Microwave Studio(MWS). The "whispering
gallery" mode TM6,1,1 with an unload Q of 100000 was chosen to oscillate in the
cavity. An energy multiplication factor of 1.99 and a peak power gain of 6.34
were achieved theoretically.
