Surface integral equation analysis of gyrotron quasi-optical launchers using the multi level fast multipole method

Neilson, Jeff; Bunger, R.

doi:10.1109/plasma.2003.1228625

Cited by 3 publications

(4 citation statements)

References 0 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Here, a n (z) and b n (z) are numerically optimized to form a Gaussian like field pattern at far field 6 . In order to investigate the conversion performance, a model launcher was fabricated for TE 22,6 mode at 110 GHz, and tested with low power.…”

Section: Optimization Of the Launcher And Low Power Testmentioning

confidence: 99%

See 1 more Smart Citation

The Designs of High Efficiency Launcher of Quasi-Optical Mode Converter for High Power Gyrotrons

Minami¹,

Kasugai²,

Takahashi³

et al. 2007

Int J Infrared Milli Waves

View full text Add to dashboard Cite

A high efficiency launcher of quasi-optical (QO) mode converters for high power gyrotrons have been designed and tested. A helical cut launcher radiates the RF power via its straight cut onto the first phase correcting mirror. The launchers have been optimized for the TE 31,8 mode at 170 GHz and TE 22,6 mode at 110 GHz by numerically optimizing a launcher surface. The helical cut of the launcher has been optimized by taking the taper angle into account. Further more, the amplitude of the surface perturbation have been optimized for improved focusing in order to reduce the diffraction losses at the helical cut. Low power measurement shows a good agreement with the design. High efficiency characteristics of the design have also been calculated on the assumption of frequency downshift due to the thermal expansion of the cavity and stepwise frequency tuning by changing the operating mode. Besides, the possibility of high efficiency launcher for higher mode is discussed, and these results give the prospect to high efficiency long pulse gyrotrons.

show abstract

Section: Optimization Of the Launcher And Low Power Testmentioning

confidence: 99%

“…A numerical algorithm surface integral analysis of the launchers of QO mode converter was developed in consideration of edge diffraction losses with magnetic field integral equation (MFIE) approach (Surf3D code) by Neilson 6 . LOT (Launcher Optimization Tool) is a computer code for the design of QO launchers optimizing a converter surface.…”

Section: Introductionmentioning

confidence: 99%

The Designs of High Efficiency Launcher of Quasi-Optical Mode Converter for High Power Gyrotrons

Minami¹,

Kasugai²,

Takahashi³

et al. 2007

Int J Infrared Milli Waves

View full text Add to dashboard Cite

show abstract

“…The aperture of the elements of the launcher of QO mode converter are comparatively small on the wavelength scale, thus causing significant diffraction losses. In order to reduce the diffraction loss, a launcher of QO mode converter was designed using the codes developed by Neilson [9].…”

Section: Introductionmentioning

confidence: 99%

High Efficiency Mode Converter for Low-Frequency Gyrotron

Minami

Kariya

Imai

et al. 2010

J Infrared Milli Terahz Waves

View full text Add to dashboard Cite

A high efficiency quasi-optical (QO) mode converter for high-power, low-frequency gyrotron have been designed and tested. For low-frequency gyrotrons, the scales of the mode converter are comparatively small on the wavelength scale, thus causing significant diffraction losses. Over-1 MW power gyrotron with TE 8,3 cavity at 28 GHz have been developed, which has a high efficiency mode converter designed by the use of numerical methods for launcher optimization. This calculation is sufficiently optimized to maximize the fractional Gaussian content of the far field. The total transmission efficiency from the mode converter to output window is 94.7%. For the experimental result of first tube, the output power of more than 1 MW has been obtained with about 40% efficiency and output burn pattern agrees fairly with the calculated profiles, which imply the design appropriateness. Besides, the frequency dependence for diffraction loss is discussed, and these results give the guiding design principle of the mode converter for high-power, low-frequency and long-pulse gyrotrons.

show abstract

“…One is large stray radiation from the built-in mode converter. Regarding this problem, the prospect for the reduction of stray radiation in the gyrotron has been already obtained by the new mode converter with high mode conversion efficiency designed by CCR-LOT Code [16]. Another issue is the large beam current decrease caused by the emission cooling of the cathode.…”

Section: Introductionmentioning

confidence: 99%