Application of a cryogenic vector network measuring technique in a high-speed digital test

The result of a digital transmission test of a YBa/sub 2/Cu/sub 3/Ox/MgO/Au microstrip line to coplanar waveguide transmission line converter is reported. It was fabricated in order to introduce a microwave design technology for high-speed digital testing. The performance was verified using a cryogenic vector network measuring technique. The transmission characteristics of the microstrip line to coplanar waveguide transmission line converter was almost the same as YBa/sub 2/Cu/sub 3/Ox/MgO/Au microstrip line at frequencies from 40 MHz to 10 GHz at 30 K. The bit error rate was analyzed using a 2/sup 23/-1 pseudo random binary signal at 3 GHz. The degradation of the bit error rate caused by the microstrip line to coplanar waveguide transmission line converter and the measuring system itself are discussed using the Q factor of the signal obtained from the bit error rate analysis and the transmission characteristics obtained by the vector network measurement.