A Virtual Cathode Oscillator With An Axially Extracted TE₁₀ Or TE₁₁ Mode

A virtual cathode oscillator with an axially extracted TE10 or TE11 mode has been investigated using the PIC code. It can emit microwaves axially through an antenna without mode converter or transition waveguide, making the system more simple and compact. The efficiency of this device can be enhanced by employing premodulation cavity, resonant cavity, feedback mechanism, and virtual cathode formed by two electron beams.A virtual cathode oscillator with an axially extracted TE10 or TE11 mode based on the Tomachan accelerator in our laboratory is investigated using the PIC simulation code. The Tomachan accelerator can run with an electron beam of 400keV and 8.9kA. Microwaves of 500MW, 2.1GHz are obtained in the PIC simulation. Microwaves can be extracted by a cylindrical waveguide of TE11 mode or a rectangular waveguide of TE10 mode. The beam-to-microwave efficiency is about 14%. The frequency and mode of the generated microwave are very pure. These results can provide a possible method for constructing a compact high-power microwave device.In addition, a virtual cathode oscillator with an axially extracted TE11 mode based on the Spark05 accelerator in our laboratory has also been investigated using the PIC simulation code. The electron beam of the Spark05 accelerator is with 580keV and 10.6kA. Microwaves of 1GW, 2.1GHz are obtained in PIC simulation. The beam-to-microwave efficiency is about 16%. The frequency and mode of the generated microwave are also very pure.A virtual cathode oscillator with axially extracted TE10 mode of rectangular waveguide has been designed and manufactured. The measurement system which is used to diagnose microwaves emitted by the virtual cathode oscillator has been prepared.