Evaluation of integrated tuning elements with SIS devices

The resonance of integrated tuning stubs in combination with SIS detectors is measured and modeled. The predicted resonances are compared with measurements of stubs integrated with Nb/Al2O3/Nb junctions in a log-periodic antenna using a Michelson interferometer. Different stub lengths were made on different substrates (on 200 micron thick quartz and on a 7 micron thick silicon membrane) and the results show a fairly good agreement with the model calculations. Quartz substrates showed resonances up to 580 GHz, silicon membrane stub resonances reach as high as 480 GHz. An observed resonance at 560 GHz is probably a substrate effect from the membrane. The gap frequency for all the samples is 650 GHz and no resonances are detected above this frequency. Up to the maximum detected frequency dispersion is found to be negligible.