Transmission Line Designs With a Measured Step Response of 3 ps Per Centimeter

Abstract

In order to effectively exploit the extreme speed and sensitivity potential of both the electro-optic and superconducting technologies, proper generation, coupling, and propagation of signals with bandwidths in excess of 100 Gigahertz is required. In this report we present results of an experimental investigation, supported by theoretical predictions, on a transmission structure which satisfies the ultra wide bandwidth requirements. The experiments, which incorporated a new variation of an electro optical sampling technique [1], investigated the generation of picosecond electrical pulses, an impedance matching tapered coupling configuration, and the propagation of the pulses down the transmission line. The technique allows the measurement of the waveforms at any point along the transmission line while minimizing dispersional effects associated with the sampling. This resulted in an accurate determination of pulse degradation, i.e., step response, per unit length of transmission line. The investigation supports the conclusion that transmission lines and connectors capable of supporting bandwidths in excess of 100 Gigahertz, while allowing relatively dispersionless propagation over distances exceeding a centimeter, are realizable.