An integrated 125GHz Sensor with read-out circuit for permittivity measurement of liquids

In this publication an integrated dielectric sensor with read-out circuit in SiGe BiCMOS technology at 125GHz is presented. The sensor consist of a 500 µm shorted half-wave coplanar waveguide transmission line in the top metal layer. Read-out of the sensor is performed by measurement of its reflection coefficient with an integrated multiprobe reflectometer and signal source. The MMIC has been fabricated in a 190-GHz fT SiGe:C BiCMOS technology and assembled on a printed circuit board. Functionality of the sensor is demonstrated with a stimulus frequency from 118 to 133GHz with immersion of the sensor into a binary methanol-ethanol mixture.