A CEA Concentration Measurement System Using FPW Biosensors and Frequency-shift Readout IC

In this paper, a CEA (carcinoembryonic antigen) concentration measurement system using flexural plate wave (FPW) biosensors and a frequency-shift readout IC is presented. The proposed frequency-shift readout method employs a programmable frequency generator and a peak detecting scheme to estimate the resonant frequency. The programmable frequency generator provides a frequency scanning range from 0.9 MHz to 25 MHz according to the characteristics of the FPW biosensors. Particularly, the proposed frequency-shift readout circuit filters and amplifies the FPW biosensors signals such that the requirements for the following voltage peak detector can be relaxed. Therefore, the sensitivity and performance of the CEA sensing system are also enhanced. The sensitivity of the peak detector is 5 mV at the highest signal rate, 50 MHz. The proposed frequency-shift readout circuit is implemented using a typical 0.18 mu m CMOS technology. The power consumption of the proposed CEA concentration measurement system is 7.69 mW justified by HSPICE simulations.