U. Bhattacharya et al., DC-725 GHZ SAMPLING CIRCUITS AND SUBPICOSECOND NONLINEAR TRANSMISSION-LINES USING ELEVATED COPLANAR WAVE-GUIDE, IEEE microwave and guided wave letters, 5(2), 1995, pp. 50-52
Nonlinear transmission lines (NLTL's) fabricated with Schottky diodes
on GaAs were used to electrically generate 3.7-V step functions that h
ad a measured 10%-90% fall time of 0.68 ps. These NLTL's were integrat
ed on wafer with sampling circuits that had a measured 3-dB bandwidth
of 725 GHz. Key to circuit performance are the use of low-loss, high-w
ave-velocity elevated coplanar waveguide transmission lines and the el
imination of active device pad parasitics by contacting devices above
the plane of the wafer.