Performance of Wideband Receiving Devices with Josephson Junctions

Abstract

In recent experiments, fairly high sensitivity of some Josephson junction receivers has been demonstrated (see reviews [1-3]). The theoretical analysis of their performance limits, however, has not been completed even within the framework of the simple and convenient “Resistively Shunted Junction” (RSJ) model (e.g., see [4]). The reason is that the best sensitivity can be achieved in the case most difficult for calculations, when the reduced signal source resistance R E is comparable with the normal resistance of the Josephson junction [5], and the signal frequency f is of the order of the junction “characteristic frequency” f C , typically from 100 to 500 GHz. The adequate analysis in the case of arbitrary R E and f, occurs to be possible for wideband source-junction coupling with no essential reactances for all frequencies comparable with f. Following are the results of the analysis of noise performance limits for the most principal types of the Josephson-effect-based receivers (see [6] for details of calculations).