title: Low-noise heterodyne receiver for electron cyclotron emission imaging and microwave imaging reflectometry.
abstract: The critical component enabling electron cyclotron emission imaging (ECEI) and microwave imaging reflectometry (MIR) to resolve 2D and 3D electron temperature and density perturbations is the heterodyne imaging array that collects and downconverts radiated emission and/or reflected signals (50-150 GHz) to an intermediate frequency (IF) band (e.g. 0.1-18 GHz) that can be transmitted by a shielded coaxial cable for further filtering and detection. New circuitry has been developed for this task, integrating gallium arsenide (GaAs) monolithic microwave integrated circuits (MMICs) mounted on a liquid crystal polymer (LCP) substrate. The improved topology significantly increases electromagnetic shielding from out-of-band interference, leads to 10× improvement in the signal-to-noise ratio, and dramatic cost savings through integration. The current design, optimized for reflectometry and edge radiometry on mid-sized tokamaks, has demonstrated >20 dB conversion gain in upper V-band (60-75 GHz). Implementation of the circuit in a multi-channel electron cyclotron emission imaging (ECEI) array will improve the diagnosis of edge-localized modes and fluctuations of the high-confinement, or H-mode, pedestal.
authors.affiliation: Princeton Plasma Physics Laboratory, Princeton, New Jersey 08543, USA.
authors.forename: B
authors.initials: B
authors.lastname: Tobias
authors.affiliation: University of California at Davis, Davis, California 95616, USA.
authors.forename: C W
authors.initials: CW
authors.lastname: Domier
authors.affiliation: University of California at Davis, Davis, California 95616, USA.
authors.forename: N C
authors.initials: NC
authors.lastname: Luhmann
authors.affiliation: University of California at Davis, Davis, California 95616, USA.
authors.forename: C
authors.initials: C
authors.lastname: Luo
authors.affiliation: University of California at Davis, Davis, California 95616, USA.
authors.forename: M
authors.initials: M
authors.lastname: Mamidanna
authors.affiliation: University of California at Davis, Davis, California 95616, USA.
authors.forename: T
authors.initials: T
authors.lastname: Phan
authors.affiliation: University of California at Davis, Davis, California 95616, USA.
authors.forename: A-V
authors.initials: AV
authors.lastname: Pham
authors.affiliation: University of California at Davis, Davis, California 95616, USA.
authors.forename: Y
authors.initials: Y
authors.lastname: Wang