Analysis of On-Chip Impedance Spectroscopy Methodologies for Sensor Arrays

Despite the great number of exciting applications for chip-scale, impedance-based sensor arrays, almost no on-chip instrumentation circuitry exists to support such systems. This void is inhibiting further research with many nanotechnology sensors and impeding the full potential of many related applications. This paper outlines the key requirements for instrumentation circuitry to measure the complex impedance of sensor arrays. It analyzes the three most likely approaches for filling this void: FFT, FRA, and a recently introduced rapid FRA system. The requirements and tradeoffs in the on-chip realization of each approach are presented, and the rapid FRA method is shown to provide the best combination of speed and hardware simplicity.