Design, Fabrication and Characterization of a Microwave Resonator ...

4.3 Calibration4.3 CalibrationIn order to eliminate systematic errors resulting from mismatches, reflections, crosstalks etc.in the NVA and feed cables, the setup is calibrated with known calibration standards. Thesecalibration standards are connectors including a short, an open, a broadband load terminationand a through, matched to 50 Ω. When starting this work, the calibration techniqueswere already well established (see [12], [5], here also further information about temperaturedependent calibrations can be found). All calibrations were performed at room temperature.We used two different calibration schemes for transmission and reflection.In transmission, a 50 Ω through adapter was connected in between the feedlines. TheNVA then provides a response calibration function where the calibration data is recorded. Inmeasurements, the measured data is then normalized to the calibration data. This calibrationis very simple, but eliminates only two of twelve possible errors.In most measurements we only calibrated the feed cables connected to the cryostat. Forphase measurement we decided to record data where the cables in the cryostat were alsocalibrated. At resonance all power is transmitted and the output power should reach 0 dB.Reflection measurements were calibrated with 1-port calibration. Therefore, we connectedthe cables in the cryostat with an 50 Ω adapter. One of the feed throughs on topof the cryostat was connected to the NVA (the feed cables to the cryostat are numbered becauseone should always use the same cables for reflection measurements) the other feedthrough was terminated with a short, an open and a broadband load. The NVA provides aroutine to calibrate the reflection measurement with all these standards. While measuringthe feed through not connected with a feed cable has to be terminated with the broadbandload.37