We report the studies of a free running virtual cathode oscillator radiating in the S-band. Although this vircator is acting as a nonresonant device, the radiation bandwidth is relatively narrow ($LS 2%), almost comparable to the results obtained when a high Q cavity is used ($LSEQ 1%). The customary chirping behavior of the RF pulse is absent in our measurements. The virtual cathode oscillator is radiating in a single mode identified as TM$-01$/ mode by using microwave-gas breakdown techniques. The measured peak power is approximately 300 MW. The mode pattern is strongly affected by the presence of electrons inside the waveguide.
展开▼
