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

5 MeasurementsFigure 5.1: Transmission S 21 of R20 and R22 at 4 K in the hybrid box. Since the recordeddata from R22 was uncalibrated a level of 20 dB is added to the data.name design W S length frequency capacitance substrate[µm] [µm] [mm] [GHz] value materialR24 Custom 1 10 20 9.8 6.403 undercoupled 1.1 fF SapphireTable 5.3: Description of the resonator R24 on Sapphire.measurement.One reason why we saw resonance peaksthat could not be identified with resonatorsand had low quality factors could be thedifferent fabrication techniques used by ourgroup and the group in Yale. Frunzio [6]uses a lift off process, our group, in contrast,uses a RIE process that could lead tothe observed very sharp edges of our structures(an electron-beam micrograph isshown in Figure 5.2). At these edges theelectric field diverges.Figure 5.2: Coupling Capacitance of R20(same as Figure 3.1 on page 29)40