Behavioral modeling and simulation of a chemical sensor with its microelectronics front-end interface

A surface acoustic wave (SAW) device is used in this work as the sensing element for a chemical sensor that will be embedded in a wireless sensor node. The SAW device is intended to detect the concentration of gaseous mercury in the environment. Two behavioral models of the SAW device have been studied. The microelectronics front-end architecture has been designed at transistor level in a 0.35 mum CMOS technology. The SAW device is embedded in a phase-locked loop (PLL) that converts the change of concentration of gaseous mercury into a shift of the loop frequency. Finally, the simulation of the overall sensor has been carried out considering a model of the SAW device described in the Hardware Description Language Verilog-A.