[Table of Contents]

Plasma and Fusion Research

Volume 5, 030 (2010)

Rapid Communications

Optics Design for Microwave Imaging Reflectometry in LHD
Tomokazu YOSHINAGA, Yoshio NAGAYAMA, Daisuke KUWAHARA1), Hayato TSUCHIYA, Soichiro YAMAGUCHI2), Yuichiro KOGI3), Shunji TSUJI-IIO1), Hitoshi HOJO4) and Atsushi MASE5)
National Institute for Fusion Science, 322-6 Oroshi, Toki 509-5292, Japan
1)
Tokyo Institute of Technology, 2-12-1 Ookayama, Meguro 152-8550, Japan
2)
Kansai University, 3-3-35 Yamate, Suita 564-8680, Japan
3)
Fukuoka Institute of Technology, 3-30-1 Wajiro-Higashi, Fukuoka 811-0295, Japan
4)
University of Tsukuba, 1-1-1 Tennodai, Tsukuba 305-8577, Japan
5)
Kyushu University, 6-1 Kasuga-Koen, Kasuga 816-8680, Japan
(Received 26 May 2010 / Accepted 1 July 2010 / Published 27 August 2010)

Abstract

An optics system for microwave imaging reflectometry (MIR) in the Large Helical Device (LHD) was newly developed to optimize the performance of the two-dimensional microwave receiver array. Reflected microwaves from the plasma and the first local oscillator (LO) wave are transmitted to the receiver array via the optics from the front. Finite-difference time-domain (FDTD) calculation was used to design the ellipsoidal or hyperboloidal shapes of the quasi-optical mirrors. It is confirmed that the LO beam in the constructed system covers the receiver antenna aperture area as intended. The S/N ratios of the signals are improved with this optimized optics system from those in the previous system.

Keywords

microwave imaging reflectometry, quasi-optics design, finite-difference time-domain method

DOI: 10.1585/pfr.5.030

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References

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This paper may be cited as follows:

Tomokazu YOSHINAGA, Yoshio NAGAYAMA, Daisuke KUWAHARA, Hayato TSUCHIYA, Soichiro YAMAGUCHI, Yuichiro KOGI, Shunji TSUJI-IIO, Hitoshi HOJO and Atsushi MASE, Plasma Fusion Res. 5, 030 (2010).