This paper presents the design, simulation, and experimental verification of an electronic modulator circuit, which is a critical functional component for an acoustic wireless sensor that can simultaneously measure temperature and pressure within an injection mold. Through a stack of piezoceramic rings, the sensor is powered by energy harvested from the mold pressure differential. Based on the concept of nonlinear network theory, the amount of energy for pressure and temperature modulation is quantitatively defined by calculating the current and voltage thresholds of the modulator circuit. Results from the analytical model have shown that by optimizing the parameters of the circuit, the sensor can be properly powered by energy harvested from the molding process for data acquisition and transmission. The simulation result was then experimentally verified using a prototyped circuit. Pressure measurement resolution of 0.12% of the full scale (100 MPa) and temperature sensitivity of 4.8 kHz/°C were obtained from the experiments.

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