Monolithic coaxial transmission lines for mm-wave ICs

A transmission line with potential application to terahertz ICs has been fabricated and characterized. The transmission line is a coaxial (shielded) line which is integrable and compatible with existing monolithic microwave integrated circuit (MMIC) technology. The structure is composed of a center conductor surrounded by a homogeneous dielectric (probimide), covered entirely by a gold plated ground plane. The coaxial lines are terminated to coplanar waveguide pads for on-wafer microwave measurements. The loss and other lumped transmission line parameters were extracted from the measured S-parameter data. The simulation results based on initial experimental data suggest the usefulness of coaxial line in the frequency range above 200 GHz. The shielded coaxial lines have the following characteristics: no radiation losses, no crosstalk between adjacent lines which enables denser IC design, compatible with existing MMIC technology, and easy transition to microstrip and coplanar waveguides.<
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