A fast FPW allergy analyzer prototype for point of care (POC)

An IgE antigen concentration analyzer system using a pair of two-port FPW (flexural plate-wave) sensors is proposed in this paper. The proposed system utilizes a frequency-shift readout method based on a peak detecting scheme to measure the resonant frequency shift. The frequency-shift readout circuit is integrated on silicon composed of a linear frequency generator, two peak detectors, two registers, and a subtractor. The frequency sweep range is from in 0.5 MHz to 11.6 MHz according to the characteristics of the FPW allergy biosensor. The sensitivity of the peak detector is 5 mV. The proposed frequency-shift readout circuit is verified by a prototype on PCB, where the maximal power consumption is 54 mW@5 kHz clock.