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Noise and Bandwidth Measurements of Diffusion-Cooled Nb Hot-Electron Bolometer Mixers at Frequencies Above the Superconductive Energy GapDiffusion-cooled Nb hot-electron bolometer (HEB) mixers have the potential to simultaneously achieve high intermediate frequency (IF) bandwidths and low mixer noise temperatures for operation at THz frequencies (above the superconductive gap energy). We have measured the IF signal bandwidth at 630 GHz of Nb devices with lengths L = 0.3, 0.2, and 0.1 micrometer in a quasioptical mixer configuration employing twin-slot antennas. The 3-dB EF bandwidth increased from 1.2 GHz for the 0.3 gm long device to 9.2 GHz for the 0.1 gm long device. These results demonstrate the expected 1/L squared dependence of the IF bandwidth at submillimeter wave frequencies for the first time, as well as the largest EF bandwidth obtained to date. For the 0.1 gm device, which had the largest bandwidth, the double sideband (DSB) noise temperature of the receiver was 320-470 K at 630 GHz with an absorbed LO power of 35 nW, estimated using the isothermal method. A version of this mixer with the antenna length scaled for operation at 2.5 THz has also been tested. A DSB receiver noise temperature of 1800 plus or minus 100 K was achieved, which is about 1,000 K lower than our previously reported results. These results demonstrate that large EF bandwidth and low-noise operation of a diffusion-cooled HEB mixer is possible at THz frequencies with the same device geometry.
Document ID
20000070856
Acquisition Source
Headquarters
Document Type
Preprint (Draft being sent to journal)
Authors
Wyss, R. A. (Jet Propulsion Lab., California Inst. of Tech. Pasadena, CA United States)
Karasik, B. S. (Jet Propulsion Lab., California Inst. of Tech. Pasadena, CA United States)
McGrath, W. R. (Jet Propulsion Lab., California Inst. of Tech. Pasadena, CA United States)
Bumble, B. (Jet Propulsion Lab., California Inst. of Tech. Pasadena, CA United States)
LeDuc, H. (Jet Propulsion Lab., California Inst. of Tech. Pasadena, CA United States)
Date Acquired
September 7, 2013
Publication Date
January 1, 1999
Subject Category
Instrumentation And Photography
Meeting Information
Meeting: Space THz Technology
Location: Charlottesville, VA
Country: United States
Start Date: March 16, 1999
End Date: March 18, 1999
Distribution Limits
Public
Copyright
Work of the US Gov. Public Use Permitted.

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