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Sub-Micron Long HTS Ho Electron MixersThe hot-electron bolometer mixer made from a high-T, superconductor (HTS) was introduced recently as an alternative to a Schottky mixer at THz frequencies. The performance of the mixer depends on the total thermal conductance for heat removal from the phonon sub-system due to either length-dependent phonon diffusion or phonon escape to the substrate. We have measured both the length and temperature dependencies of the IF bandwidth of the mixers fabricated from 25-35 mn thick YBCO films on MgO and sapphire substrates. The films were grown by a laser deposition technique and electron-beam lithography was used to define bridge lengths down to 50 nm. Mixer measurements were done using signal frequencies in the range of 1-100 GHz. For 50 nm and 400 nm long devices on MgO, the 3-dB bandwidth was about 100 MHz. At temperatures below 60 K, the hot-electron plateau was clearly seen starting around 2-3 GHz. At temperatures above 70 K, the flux-flow effects begin to dominate and the IF bandwidth increases to 1-8 GHz, while the conversion efficiency drops by several dB. This temperature dependence of the IF bandwidth can account for previously reported unexpectedly high bandwidth of HTS mixers.
Document ID
20010001502
Acquisition Source
Jet Propulsion Laboratory
Document Type
Other
Authors
Harnack, 0.
(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)
Kleinsasser, A. W.
(Jet Propulsion Lab., California Inst. of Tech. Pasadena, CA United States)
Barner, J. B.
(Jet Propulsion Lab., California Inst. of Tech. Pasadena, CA United States)
Date Acquired
August 20, 2013
Publication Date
January 1, 2000
Subject Category
Atomic And Molecular Physics
Distribution Limits
Public
Copyright
Work of the US Gov. Public Use Permitted.

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