Quasi-Optics In High Power Millimeter Wave Systems

Petelin, M. I.

doi:10.1063/1.1635126

Cited by 20 publications

(13 citation statements)

References 15 publications

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“…As long-term perspective, switching of a high-power beam generated from several continuously operating sources can be provided by using a multiplexer fed by a set of frequency-controlled gyrotrons [3,4,5,6,7]. Infinitely variable beam steering could become possible with a phased array fed by a set of gyrotrons (or high-order-mode gyroklystrons) which are phase locked to a common low-power reference oscillator via electrically controlled phase shifters [4,5,7,8,9,10].…”

Section: Introductionmentioning

confidence: 99%

A fast switch, combiner and narrow-band filter for high-power millimetre wave beams

Kasparek¹,

Petelin²,

Shchegolkov³

et al. 2008

Nucl. Fusion

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Abstract.A fast directional switch (FADIS) is described, which allows controlled switching of high-power microwaves between two outputs. A possible application could be synchronous stabilization of neoclassical tearing modes (NTM). Generally, the device can be used to share the installed EC power between different types of launchers or different applications (e.g. in ITER, midplane / upper launcher). The switching is performed electronically without moving parts by a small frequency-shift keying of the gyrotron (some tens of MHz), and a narrow-band diplexer. The device can be operated as a beam combiner also, which offers attractive transmission perspectives in multi-megawatt ECRH systems. In addition, these diplexers are useful for plasma diagnostic systems employing high-power sources due to their filter characteristics. The principle and the design of a four-port quasi-optical resonator diplexer is presented. Lowpower measurements of switching contrast, mode purity and efficiency show good agreement with theory. Preliminary frequency modulation characteristics of gyrotrons are shown, and first results from high-power switching experiments using the ECRH system for W7-X are presented.

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Section: Introductionmentioning

confidence: 99%

A fast switch, combiner and narrow-band filter for high-power millimetre wave beams

Kasparek¹,

Petelin²,

Shchegolkov³

et al. 2008

Nucl. Fusion

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“…the Mach-Zehnder type [2,6]), multibeam interferometers (Fabry-Perot type, or ring resonator [1,3]) and combinations thereof. As high-power compatible hybrids, low-loss dielectric beam splitters [2,6], metallic phase gratings (magic Y) [4,10], and square corrugated waveguides [5,11] have been identified up to now. In principle, any of the solutions found can be integrated into corrugated waveguide as well as in beam waveguide transmission systems by using appropriate interface elements.…”

Section: Designs For High-power Diplexersmentioning

confidence: 99%

“…Within the experimental possibilities of these mock-ups, a good agreement with theory is obtained for all set ups. Details can be found in the respective references [2][3][4][5][6][7][8][9][10][11][12]. The quasi-optical resonant diplexer was as well exposed to high-power tests, which were performed at the ECRH system for the stellarator W7-X [13].…”

Section: Experimental Investigationsmentioning

confidence: 99%

High-power microwave diplexers for advanced ECRH systems

Kasparek

Petelin

Erckmann

et al. 2009

Fusion Engineering and Design

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In Electron cyclotron resonance heating systems, high-power multiplexers can be employed as power combiners, adjustable power dividers, fast switches to toggle the power between two launchers, as well as frequency sensitive directional couplers to combine heating and diagnostic applications on one launcher. In the paper, various diplexer designs for quasi-optical and corrugated waveguide transmission systems are discussed. Numerical calculations, low-power tests and especially high-power experiments performed at the ECRH system of W7-X are shown, which demonstrate the capability of these devices. Near term plans for applications on ASDEX Upgrade and FTU are presented. Based on the present results, options for implementation of power combiners and fast switches in the ECRH system of ITER is discussed.

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“…Once frequency-controllable gyrotrons [11,12,13] are available, the wide range of applications of high-power diplexer would become available, including staggering of these devices for multiplexers [12].…”

Section: Conclusion and Future Perspectivementioning

confidence: 99%

Power Combination of Two 140-GHz Gyrotrons and Fast Switching of the Combined Beam

Erckmann

Kasparek

Koshurinov

et al. 2009

Fusion Science and Technology

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Experiments on the combination of the high power wave beams from two gyrotrons and fast switching of the combined beam between two transmission channels are described. The measurements were performed using a high-power resonator diplexer in the optical transmission line of the electron cyclotron heating system for W7-X. The principle and the engineering design of the prototype fourport quasi-optical diplexer is presented. The wave beams from two gyrotrons with an output power of 370 kW and 560 kW, respectively, have been combined for pulse lengths up to 10 seconds, only limited by the un-cooled mirrors used in the diplexer. By modulating the gyrotron frequency using a fast high-voltage body modulator, controlled toggling of the combined power between the two outputs of the diplexer was demonstrated with switching frequencies of up to 20 kHz.The experiments are compared to theory, showing good agreement when the limited stability of the free-running gyrotrons is taken into account.

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Quasi-Optics In High Power Millimeter Wave Systems

Cited by 20 publications

References 15 publications

A fast switch, combiner and narrow-band filter for high-power millimetre wave beams

A fast switch, combiner and narrow-band filter for high-power millimetre wave beams

High-power microwave diplexers for advanced ECRH systems

Power Combination of Two 140-GHz Gyrotrons and Fast Switching of the Combined Beam

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