IC-Compatible Low Loss Passive Circuits for Millimeter-Wave Applications

This paper reports a novel low-loss and IC-compatible technological solution to improve coplanar passive circuit´s performances on low-resistivity silicon substrate (LRS) in order to demonstrate the feasibility of tailoring locally the silicon substrate to speed up the performance of a system. Both EM-simulations and high-frequency characterizations have shown an important benefit in CPW circuits performances by combining bulk silicon micromachining technique and low-k polymer membrane. An attenuation coefficient of 0.57 dB/cm is obtained at 20 GHz with this technique in the case of a CPW line on 20-30 Omega.cm silicon substrates. The V-band suspended CPW band-pass filter on BCB membrane has shown 3.6 dB insertion loss improvement compared to those realized on top of bulk high-resistivity (HR) silicon substrate with thick polymer interface layer