Cantilever-Based Microwave Biosensors: Analysis, Designs and Optimizations

This paper presents a novel microwave readout scheme for measuring deflection of cantilevers in nanometer range. The cantilever deflection can be sensed by the variation of transmission levels or resonant frequencies of microwave signals. The sensitivity of the cantilever biosensor based on LC resonators is at first theoretically analyzed.

A LC resonator based biosensor with beams is designed and optimized by using 3D electromagnetic (EM) simulations, where the beam is a typical variation of cantilevers. The sensitivity of the lossless biosensor is predicted as 4.6MHz/nm. The 3-dB bandwidths of the resonances are narrowed for improving the resolution of distinguishing resonances by reducing conductive loss of electrodes.

The lossy biosensor can achieve the highest sensitivity as 5.6 MHz/nm and narrowest 3-dB bandwidth as 5 GHz.