Experimental Stydy of Noise Generated by Magnetrons for Microwave Owens

Yamamoto, Kosuke; Kuronuma, H.; Koinuma, T.; Koinuma, N.

doi:10.1080/16070658.1981.11689249

Cited by 8 publications

(3 citation statements)

References 4 publications

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“…The signal exhibits a copious amount of close-in noise (we define the close-in noise as the noise observed within approximately 50 MHz from the carrier). Two sidebands are also evident, spaced about 120 MHz from the carrier, believed to be caused by the recirculating electrons [14]. An additional peak located at about 240 MHz from the carrier is presumably a second harmonic of the 120 MHz sidebands.…”

Section: Magnetron Experimental Data For Azimuthally Varying Aximentioning

confidence: 97%

Low-Noise Microwave Oven Magnetrons With Fast Start-Oscillation by Azimuthally Varying Axial Magnetic Fields

Neculaes

Gilgenbach

Lau

et al. 2004

IEEE Trans. Plasma Sci.

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A technique has been proven to significantly reduce the noise and to hasten the startup in microwave signals from dc operating oven magnetrons. The technique is based on imposition of an azimuthally varying axial magnetic field in magnetrons. For an -cavity magnetron operating in pi-mode, the optimal number of periods of azimuthal variations in the axial magnetic field is 2. This technique demonstrates the fastest startup and lowest start-oscillation current by prebunching the electrons. Measurements show dramatic reduction in noise of 600-800 W oven magnetrons operating dc near 2.45 GHz. The sidebands are eliminated ( 30 dB) and the noise within 50 MHz from the carrier is reduced by 30 dB. Noise reduction is observed at low (up to 60 mA), medium (60-200 mA) and high currents (200-300 mA), for both aged and fresh oven magnetrons. The reduction in power and in electronic efficiency is of order of 10%, in this low-noise, fast startup operation.Index Terms-High power microwaves, magnetron, microwave noise.

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Section: Magnetron Experimental Data For Azimuthally Varying Aximentioning

confidence: 97%

Low-Noise Microwave Oven Magnetrons With Fast Start-Oscillation by Azimuthally Varying Axial Magnetic Fields

Neculaes

Gilgenbach

Lau

et al. 2004

IEEE Trans. Plasma Sci.

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“…This is noise generated in synchrony with the electron circulation as indicated in Ref. 1. The frequency of the noise generated in synchrony with the electron circulation is theoretically given by the following formula [10]:…”

Section: Time Domain Analysis Of Low-frequency Line Noisementioning

confidence: 99%

“…In the case of a microwave oven, the line noise leaking from the magnetron is a major problem. The causes of line noise generation reported in the past include noise generated in synchrony with the electron circulation, noise due to ion plasma vibration, noise due to ion relaxation vibration, and their intermodulations [1]. However, there are many unknown factors regarding the noise sources of magnetrons.…”

Section: Introductionmentioning

confidence: 99%

Time domain analysis of noises generated from microwave oven magnetron

Mitani¹,

Shinohara²,

Matsumoto³

et al. 2005

Electron. Comm. Jpn. Pt. II

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Low-noise microwave magnetrons by azimuthally varying axial magnetic field

Neculaes

Gilgenbach

Lau

2003

Applied Physics Letters

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A technique has been demonstrated to significantly reduce the noise in microwave oven magnetrons. The technique employs permanent magnets to generate an azimuthally varying axial magnetic field. Noise measurements are reported which show dramatic reductions in the noise of kW oven magnetrons operating near 2.45 GHz. The noise reduction near the carrier is some 30 dB. Microwave sidebands are reduced or eliminated. Noise reduction occurs at all anode currents, but is particularly significant at low current near the start-oscillation condition.

show abstract

Experimental Stydy of Noise Generated by Magnetrons for Microwave Owens

Cited by 8 publications

References 4 publications

Low-Noise Microwave Oven Magnetrons With Fast Start-Oscillation by Azimuthally Varying Axial Magnetic Fields

Low-Noise Microwave Oven Magnetrons With Fast Start-Oscillation by Azimuthally Varying Axial Magnetic Fields

Time domain analysis of noises generated from microwave oven magnetron

Low-noise microwave magnetrons by azimuthally varying axial magnetic field

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