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

4 Fabrication and Measurement SetupGold plated box This box was designed especially for the measurements of the CPWresonators. It was produced of oxygen free copper and covered with gold to improvethe connection to ground. The resonators are put into a carefully milled recess.Figure 4.2: Connecting with silver glue (a) on connector (b) grounding on edges.For the connections to the taper lines of our resonators Rosenberger stripline SMA-Connectors (section 3.3) were used. The advantage of this decision is, that we do nothave to use bonding wires on a PCB. For better electronic contact, we put a droplet ofsilver glue between the connector pins and the taperline. For putting the silver glue onthe small pin, the microscope of the bonding machine was used. A cold light sourcehad to be used, instead of the much heat producing lamp of the bonding machine, toglue the devices, since silver glue hardens very fast. The ground planes of the DUTwere connected to the box, by putting silver glue all over the edges of the structure tothe box (Figure 4.2).After checking for shorts the sample was connected to the coaxial cables of the cryostat(Figure 4.4).The measurement setup is shown in detail in Figure 4.3.A Labview program controls the settings (like start, stop-frequency) of the Network VectorAnalyzer (NVA) and is able to record data at selected temperature steps. The magnitudeand the phase of transmission and reflection measurements were extracted from the calibrateddata returned by the NVA.34