Title :
Progress in experimental studies of harmonic multiplying gyro-amplifiers
Author :
Guo, H. ; Granatstein, V.L. ; Rodgers, J. ; Zhao, J.J. ; Chen, W.J. ; Miao, Y.
Author_Institution :
Inst. for Plasma Res., Maryland Univ., College Park, MD, USA
Abstract :
Summary form only given. The University of Maryland is investigating gyro harmonic multiplication as a new means of coherently generating high frequency, large bandwidth, high power microwaves with reduced magnetic field, lower noise and high sub-harmonic injection gain. Significant progress has been made in frequency doubling devices. One of them is the phase-coherent harmonic-multiplying inverted gyroklystron (the phigtron), which consists of a Ku-band fundamental gyro-TWT input section, a Ka-band second harmonic two cavity gyroklystron output section and a long radiation-free drift space between them. This device has been characterized as a high performance millimeter wave amplifier with output peak power of 400-720 KW, saturated gain of 30-33 dB, efficiency of 30-35%, bandwidth of 0.3-0.7% and phase stability of 0.026 degree per volt of beam voltage rippling. The second one of our investigations is the Ka-band, frequency doubling, second harmonic gyro-TWT. This traveling wave amplifier utilizes a configuration similar to the phigtron with the only difference in the output section, which is now in the form of Ka-band second harmonic gyro-TWT rather than the simple cavity gyroklystron of the previous case. Preliminary hot test results have been obtained with output peak power of about 180 KW, bandwidth, 3% at central frequency of 32.8 GHz, beam voltage of 50 KV and beam current of /spl sim/30 A. We may bring better test results to the conference after further improving the B field profile and the frequency characteristics of the input coupler.
Keywords :
gyrotrons; harmonic generation; microwave amplifiers; 180 kW; 30 A; 30 to 33 dB; 30 to 35 percent; 32.8 GHz; 400 to 720 kW; 50 kV; B field profile; Ka-band frequency doubling second harmonic gyro-travelling wave tube; Ka-band second harmonic two cavity gyroklystron output section; Ku-band fundamental gyro-travelling wave tube input section; bandwidth; beam voltage rippling; coherent microwave generation; distributed loss; efficiency; frequency characteristics; frequency doubling devices; harmonic multiplying gyro-amplifiers; high frequency large bandwidth high power microwaves; hot test; input coupler; millimeter wave amplifier; mode selective interaction structures; output peak power; phase-coherent harmonic-multiplying inverted gyroklystron; phigtron; radiation-free drift space; reduced magnetic field; saturated gain; simple cavity gyroklystron; spurious oscillation suppression; sub-harmonic injection gain; traveling wave amplifier; wideband fourth harmonic gyro travelling wave tube amplifier; Bandwidth; Frequency; High power microwave generation; Klystrons; Microwave devices; Microwave generation; Power generation; Power system harmonics; Testing; Voltage;
Conference_Titel :
Plasma Science, 2000. ICOPS 2000. IEEE Conference Record - Abstracts. The 27th IEEE International Conference on
Conference_Location :
New Orleans, LA, USA
Print_ISBN :
0-7803-5982-8
DOI :
10.1109/PLASMA.2000.855008