New microstrip Directional Coupler Design for Side of Waveguide in Lower Hybrid Current Drive System on Alcator C-Mod

Author

Koert, P. ; Wallace, G. ; Parker, R. ; Terry, D.R. ; Wukitch, S.J.

Author_Institution

Plasma Sci. & Fusion Center, MIT, Cambridge, MA

fYear

2005

fDate

Sept. 2005

Firstpage

1

Lastpage

3

Abstract

We have developed a compact, mass-producible probe inserted into two holes 1/4 wavelength apart in the narrow side of the reduced height waveguides used in the lower hybrid current drive (LHCD) system. The probe consists of two magnetic loops and branch coupler mounted directly on a single microstrip circuit board, thereby greatly reducing the physical size of the probe. The transmission from magnetic loop to coupler output will be discussed in detail. The requirements for confined space and many probes positioned side by side were addressed in the package design for the probe. Calibrations have shown directivity greater than 20 dB at 4.6 GHz for each of the over 100 probes built

Keywords

Tokamak devices; fusion reactor design; microstrip directional couplers; 4.6 GHz; Alcator C-Mod; LHCD system; branch coupler; compact mass-producible probe; confined space; lower hybrid current drive system; magnetic loop; magnetic loops; microstrip circuit board; microstrip directional coupler design; package design; probe size; reduced height waveguides; Coupling circuits; Directional couplers; Leg; Magnetic confinement; Microstrip; Nuclear and plasma sciences; Phased arrays; Plasma measurements; Printed circuits; Probes;

fLanguage

English

Publisher

ieee

Conference_Titel

Fusion Engineering 2005, Twenty-First IEEE/NPS Symposium on

Conference_Location

Knoxville, TN

Print_ISBN

0-4244-0150-X

Electronic_ISBN

0-4244-0150-X

Type

conf

DOI

10.1109/FUSION.2005.252947

Filename

4018981