A novel wideband gyrotron travelling wave amplifier

We present the design and the experimental results of a novel wideband quasioptical Gyrotron Traveling Wave Tube (gyro-TWT) amplifier and the first Vacuum Electron Device (VED) with a Photonic Band Gap (PBG) structure. The theory and experimental results from two other quasioptical gyrotron oscillator experiments are also presented. The gyro-TWT amplifier at 140 GHz produced up to 30 kW of peak power in operation with 3 ts pulses at 6 Hz, 2.30 GHz unsaturated bandwidth, a peak linear gain of 29 dB and an efficiency of 12 %. This is the highest frequency gyro-TWT reported as yet. The use of a very high order operating mode in a novel mode selective interaction structure namely, a quasioptical open confocal waveguide makes the gyro-TWT potentially capable of up to 100 kW CW operation at 140 GHz and at 94 GHz in the W-band (75-110 GHz) if built to industrial standards. The theory and experimental results from the first VED with a PBG resonator, in the form of a high power high frequency gyrotron oscillator at 25 kW power level at 140 GHz in a high order mode, TE041 are also presented. The absence of any spurious mode excitation over 30 % variation in the magnetic field corresponding to an equal variation in the cyclotron frequency indicates that the PBG resonator was highly mode selective while operating in a higher order mode. This opens up promising avenues for building highly oversized resonators for generating Terahertz radiation with low voltage electron beams.

Department dc:contributor.department

Massachusetts Institute of Technology. Department of Electrical Engineering and Computer Science.

Grantor dc:publisher

Massachusetts Institute of Technology

Year dc:date.issued

2003

Author dc:creator

• Sirigiri, Jagadishwar R. (Jagadishwar Rao), 1973-

Advisor dc:contributor.advisor

• Richard J. Temkin.

• Electrical Engineering and Computer Science.

Statement dc:rights

• M.I.T. theses are protected by copyright. They may be viewed from this source for any purpose, but reproduction or distribution in any format is prohibited without written permission. See provided URL for inquiries about permission.

Licence dc:rights.uri

• http://dspace.mit.edu/handle/1721.1/7582

Language dc:language.iso

eng

Handle dc:identifier.uri

http://hdl.handle.net/1721.1/87853

OAI identifier oai:identifier

oai:dspace.mit.edu:1721.1/87853