Low-power planar complex dielectric sensor with DC readout circuit in a BiCMOS technology

Sensing the dielectric constants real part (ε') and imaginary part (ε") of a material under test (MUT) enhances the capability to differentiate between different materials. In this paper a low power dielectric sensor with two DC outputs, based on K-band sensing structure, is presented. The full solution is implemented in a standard 0.13 μm SiGe:C BiCMOS technology. Different concentrations of ethanol and methanol solutions were used to demonstrate the functionality of the proposed approach. The sensor showed a responsivity of 10mV/ε' and 100 mV/ε". The sensor can detect a variation of 0.15 of ε' and 0.002 of ε" based on phase noise measurements and simulations. With the DC outputs and a total power consumption of 74mW the proposed sensor architecture is well suited for lab-on-chip systems.