Optimized design of polarizers with low ohmic loss and any polarization state for the 28 GHz QUEST ECH/ECCD system

Toru Ii Tsujimura, Hiroshi Idei, Shin Kubo, Sakuji Kobayashi

    Research output: Contribution to journalArticle

    2 Citations (Scopus)

    Abstract

    In a high-power long-pulse millimeter-wave transmission line for electron cyclotron heating and current drive (ECH/ECCD), the ohmic loss on the grooved mirror surface of polarizers is one of the important issues for reducing the transmission loss. In this paper, the ohmic loss on the mirror surface is evaluated in simulated real-scale polarizer miter bends for different groove parameters under a linearly-polarized incident wave excitation. The polarizers with low ohmic loss are optimally designed for a new 28 GHz transmission line on the QUEST spherical tokamak. The calculated optimum ohmic loss is restricted to only less than 1.5 times as large as the theoretical loss for a copper flat mirror at room temperature. The copper rounded-rectangular grooves of the polarizers were relatively easy to make smooth in mechanical machining and the resultant surface roughness was not more than 0.15 μm, which is only 0.38 times as large as the skin depth. The combination of the designed elliptical polarizer and the polarization rotator can also realize any polarization state of the reflected wave.

    Original languageEnglish
    Pages (from-to)97-101
    Number of pages5
    JournalFusion Engineering and Design
    Volume114
    DOIs
    Publication statusPublished - Jan 1 2017

    Fingerprint

    Polarization
    Mirrors
    Copper
    Electric lines
    Wave transmission
    Cyclotrons
    Millimeter waves
    Skin
    Machining
    Surface roughness
    Heating
    Electrons
    Temperature

    All Science Journal Classification (ASJC) codes

    • Civil and Structural Engineering
    • Nuclear Energy and Engineering
    • Materials Science(all)
    • Mechanical Engineering

    Cite this

    Optimized design of polarizers with low ohmic loss and any polarization state for the 28 GHz QUEST ECH/ECCD system. / Tsujimura, Toru Ii; Idei, Hiroshi; Kubo, Shin; Kobayashi, Sakuji.

    In: Fusion Engineering and Design, Vol. 114, 01.01.2017, p. 97-101.

    Research output: Contribution to journalArticle

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