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

3.3 ConnectorsFigure 3.1: Coupling capacitors used in the paper of Frunzio el al [6].each being 4 µm wide (”fingers”) and a gap of 2 µm between those two stripes. The capacitanceof the overcoupled resonator of design 1 is done by enlarging the length and thenumber of the fingers. The length is scaled linearly compared to the Yale design, as wasdone in the undercoupled case.For design 2 only a slightly overcoupled resonator was fabricated. Here, the length ofthe fingers was enlarged, their number remained constant compared to the overcoupled resonatorof design 1.Table 3.3 gives an overview of the used dimensions. The capacitance values were calculatedusing Xic 1 .undercoupled overcoupleddesign coupling capacitance (fF) gap width # fingers lengthSapphire Silicon g (µm) (µm)Yaleundercoupled 0.58 0.69 4overcoupled 6.2 7.1 2 100design 1undercoupled 1.1 1.2 8overcoupled 21 24 3 200design 2 slighty overcoupled 31 3 350Table 3.3: Overview of the dimensions and values of the coupling capacitances.Due to the coupling capacitors the resonance frequency differs from the one the resonatorswere designed for (see (2.29)). The modified resonance frequencies and an overview of thedesigned resonators are listed in Appendix A.3.3 ConnectorsIn the design of the measurement box (refered to as ”Gold plated box”) SMA Connectors32K724-600S3 SMA from Rosenberger 2 were used. The flat center conductor pin of theconnector (diameter 510 µm) is embedded in a teflon dielectric of diameter 2.18 mm. Thepin length, not covered by dielectric on the inner side of the box is 1 mm. The connectorcan be plugged to a cable with SMA male connectors.1 www.wrcad.com2 www.rosenberger.de29