A Ka-band tunable direct-conversion correlation reflectometer for NSTX

Journal Article · Fri Oct 15 04:00:00 EDT 2010 · Review of Scientific Instruments

DOI:https://doi.org/10.1063/1.3490024· OSTI ID:22055823

Kubota, S; Peebles, W A; Nguyen, X V; Crocker, N A ^[1]; Roquemore, A L; Holoman, T; Guttadora, L; Kaita, R ^[2]

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1. Department of Physics and Astronomy, University of California, Los Angeles, California 90095 (United States)
2. Princeton Plasma Physics Laboratory, Princeton, New Jersey 08543 (United States)

The recent availability of broadband microwave quadrature mixers in the Ka-band (28-40 GHz) of frequencies has allowed the fabrication of low-cost direct-conversion detection circuits for use in the variable-frequency correlation reflectometer on the National Spherical Torus eXperiment (NSTX). The quadrature receiver in this case can be implemented as a simple homodyne circuit, without the complication of a single-sideband modulator or a feedforward tracking circuit present in more typical designs. A pair of direct-conversion receivers is coupled with broadband microwave voltage-controlled oscillators to construct a flexible dual-channel radar system with a fast frequency settling time of {approx}160 {mu}s. A detailed description of the design and a full characterization of the hardware are provided. Examples of turbulence measurements from radial and poloidal correlation reflectometry on NSTX using a poloidal array of antennas (oriented normal to the magnetic flux surfaces for conventional reflectometry) are presented.

• OSTI ID: 22055823
• Journal Information: Review of Scientific Instruments, Journal Name: Review of Scientific Instruments Journal Issue: 10 Vol. 81; ISSN 0034-6748; ISSN RSINAK
• Country of Publication: United States
• Language: English

Related Subjects

43 PARTICLE ACCELERATORS
70 PLASMA PHYSICS AND FUSION TECHNOLOGY
ANTENNAS
DESIGN
DETECTION
DIRECT ENERGY CONVERSION
FABRICATION
FREQUENCY MIXING
GHZ RANGE
MAGNETIC FLUX
MICROWAVE RADIATION
NSTX DEVICE
OSCILLATORS
RADAR
TURBULENCE