@Article{EkstromH._etal1995,
author="Ekstrom H.
and Karasik B. S.
and Kollberg E.L.
and Yngvesson K.S.",
title="Conversion Gain and Noise of Niobium Superconducting Hot-Electron-Mixers",
journal="IEEE Trans. Microw. Theory Techn.",
year="1995",
volume="43",
pages="938--947",
abstract="A study has been done of microwave mixing at 20 GHz using  the  nonlinear  (power  dependent) resistance of thin niobium strips in the resistive state. Our experiments give evidence that electron-heating is the main cause of the nonlinear phenomenon. Also a detailed phenomenological theory for the determination of conversion properties is presented. This theory is  capable of predicting the frequency-conversion loss rather accurately for arbitrary bias by examining the I-V-characteristic. Knowing the electron temperature relaxation time, and using parameters derived from the I-V-characteristic also allows us to predict the -3-dB IF bandwidth. Experimental results are in excellent agreement with the theoretical predictions. The require ments on the mode of operation and on the film parameters for minimizing the conversion loss (and even  achieving conversion gain) are  discussed in some detail. Our measurements demon-strate an intrinsic conversion loss as low as 1 dB. The maximum IF frequency defined for -3-dB  drop in conversion gain, is about 80 MHz. Noise  measurements indicate  a device output noise temperature  of about 50 K and  SSB  mixer  noise temperature below 250 K. This type of mixer is considered very promising for use in low-noise heterodyne receivers at THz frequencies.",
optnote="exported from refbase (https://db.rplab.ru/refbase/show.php?record=964), last updated on Sun, 22 May 2016 16:27:02 -0500"
}