Design of polarizers for a mega-watt long-pulse millimeter-wave transmission line on the large helical device.
The polarizer is one of the critical components in a high-power millimeter-wave transmission line. It requires full and highly efficient coverage of any polarization states, high-power tolerance, and low-loss feature. Polarizers with rounded shape at the edge of the periodic groove surface are designed and fabricated by the machining process for a mega-watt long-pulse millimeter-wave transmission line of the electron cyclotron resonance heating system in the large helical device. The groove shape of λ/8- and λ/4-type polarizers for an 82.7 GHz transmission line is optimally designed in an integral method developed in the vector theories of diffraction gratings so that the efficiency to realize any polarization state can be maximized. The dependence of the polarization states on the combination of the two polarizer rotation angles (Φλ/8, Φλ/4) is examined experimentally in a low-power test with the newly developed polarization monitor. The results show that the measured polarization characteristics are in good agreement with the calculated ones.
National Institute for Fusion Science, 322-6 Oroshi-cho, Toki 509-5292, Japan.
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Ii
National Institute for Fusion Science, 322-6 Oroshi-cho, Toki 509-5292, Japan.
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Kubo
National Institute for Fusion Science, 322-6 Oroshi-cho, Toki 509-5292, Japan.
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Shimozuma
National Institute for Fusion Science, 322-6 Oroshi-cho, Toki 509-5292, Japan.
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Kobayashi
National Institute for Fusion Science, 322-6 Oroshi-cho, Toki 509-5292, Japan.
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Okada
National Institute for Fusion Science, 322-6 Oroshi-cho, Toki 509-5292, Japan.
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Yoshimura
National Institute for Fusion Science, 322-6 Oroshi-cho, Toki 509-5292, Japan.
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Igami
National Institute for Fusion Science, 322-6 Oroshi-cho, Toki 509-5292, Japan.
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Takahashi
National Institute for Fusion Science, 322-6 Oroshi-cho, Toki 509-5292, Japan.
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Ito
National Institute for Fusion Science, 322-6 Oroshi-cho, Toki 509-5292, Japan.
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Mizuno
National Institute for Fusion Science, 322-6 Oroshi-cho, Toki 509-5292, Japan.
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Okada
Department of Energy Engineering and Science, Nagoya University, Furo-cho, Chikusa-ku, Nagoya 464-8602, Japan.
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Makino
Department of Energy Engineering and Science, Nagoya University, Furo-cho, Chikusa-ku, Nagoya 464-8602, Japan.
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Kobayashi
Department of Energy Engineering and Science, Nagoya University, Furo-cho, Chikusa-ku, Nagoya 464-8602, Japan.
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Goto
National Institute for Fusion Science, 322-6 Oroshi-cho, Toki 509-5292, Japan.
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Mutoh