A frequency-domain mixer model for diffusion-cooled hot-electron bolometers

A new frequency domain hot-electron bolometer (HEB) mixer model is describe d, which takes into account the non-uniform temperature distribution found in superconducting diffusion-cooled devices. In this model the bolometer is discretized into a finite number of segments, and the non-linear large sig nal response to local oscillator and DC heating is found by an iterative al gorithm. A frequency-domain coupling matrix is introduced to represent smal l-signal modulations around the large-signal values of temperatures and hea t flows inside the device. The coupling matrix and a Norton representation of the mixer DC and intermediate frequency (IF) circuit allows the mixer co nversion to be calculated.