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Title: Grating Polarizers at 170 GHz for ECRH Systems: Low Power Tests and Simulations

Abstract

The elliptical polarization produced by a pair of sinusoidally profiled miter-bend grating polarizers has been measured experimentally and found to be in excellent agreement with theory. The polarizers were designed to be used at 170 GHz in the miter bends of a 63.5 mm corrugated metallic waveguide for creating the arbitrary elliptically polarized microwave beam needed for electron cyclotron resonance heating of plasma. Using a vector network analyzer to generate a linearly polarized HE11 incident mode, each polarizer was individually tested to measure the rotation α and ellipticity β of the elliptically polarized reflected microwave beam as a function of the grating rotation angle. The grating polarizers were then tested together to measure the elliptical polarization as a function of the angles of the combination of the two polarizers arranged sequentially on the transmission line. The map of the ellipticity versus grating angles agreed very well with numerical simulations using high-frequency structure simulator. Numerical simulations show that up to eight combinations of rotation angles of the two grating polarizers can provide the same ellipticity but with the varying ohmic loss, thus allowing the choice of settings to minimize the ohmic loss, a necessary consideration to minimize heating effects in megawattmore » power level systems.« less

Authors:
; ; ; ;
Publication Date:
DOE Contract Number:  
FC02-93ER54186
Research Org.:
Massachusetts Inst. of Technology (MIT), Cambridge, MA (United States). Plasma Science and Fusion Center
Sponsoring Org.:
USDOE Office of Science (SC), Fusion Energy Sciences (FES)
Subject:
70 PLASMA PHYSICS AND FUSION TECHNOLOGY
OSTI Identifier:
1881480
DOI:
https://doi.org/10.7910/DVN/TPF6DZ

Citation Formats

Hoffmann, Hannah M., Jawla, Sudheer K., Shapiro, Michael A., Hanson, Gregory, and Temkin, Richard J. Grating Polarizers at 170 GHz for ECRH Systems: Low Power Tests and Simulations. United States: N. p., 2020. Web. doi:10.7910/DVN/TPF6DZ.
Hoffmann, Hannah M., Jawla, Sudheer K., Shapiro, Michael A., Hanson, Gregory, & Temkin, Richard J. Grating Polarizers at 170 GHz for ECRH Systems: Low Power Tests and Simulations. United States. doi:https://doi.org/10.7910/DVN/TPF6DZ
Hoffmann, Hannah M., Jawla, Sudheer K., Shapiro, Michael A., Hanson, Gregory, and Temkin, Richard J. 2020. "Grating Polarizers at 170 GHz for ECRH Systems: Low Power Tests and Simulations". United States. doi:https://doi.org/10.7910/DVN/TPF6DZ. https://www.osti.gov/servlets/purl/1881480. Pub date:Thu Jun 04 00:00:00 EDT 2020
@article{osti_1881480,
title = {Grating Polarizers at 170 GHz for ECRH Systems: Low Power Tests and Simulations},
author = {Hoffmann, Hannah M. and Jawla, Sudheer K. and Shapiro, Michael A. and Hanson, Gregory and Temkin, Richard J.},
abstractNote = {The elliptical polarization produced by a pair of sinusoidally profiled miter-bend grating polarizers has been measured experimentally and found to be in excellent agreement with theory. The polarizers were designed to be used at 170 GHz in the miter bends of a 63.5 mm corrugated metallic waveguide for creating the arbitrary elliptically polarized microwave beam needed for electron cyclotron resonance heating of plasma. Using a vector network analyzer to generate a linearly polarized HE11 incident mode, each polarizer was individually tested to measure the rotation α and ellipticity β of the elliptically polarized reflected microwave beam as a function of the grating rotation angle. The grating polarizers were then tested together to measure the elliptical polarization as a function of the angles of the combination of the two polarizers arranged sequentially on the transmission line. The map of the ellipticity versus grating angles agreed very well with numerical simulations using high-frequency structure simulator. Numerical simulations show that up to eight combinations of rotation angles of the two grating polarizers can provide the same ellipticity but with the varying ohmic loss, thus allowing the choice of settings to minimize the ohmic loss, a necessary consideration to minimize heating effects in megawatt power level systems.},
doi = {10.7910/DVN/TPF6DZ},
journal = {},
number = ,
volume = ,
place = {United States},
year = {2020},
month = {6}
}

Works referencing / citing this record:

Grating Polarizers at 170 GHz for ECRH Systems: Low Power Tests and Simulations
journal, September 2018