A Shape Memory Alloy Based Chipless RF Temperature Sensor

This article details the design and simulation of a chipless RF temperature sensor featuring a square-shaped tag on a Rogers Ultralam 3850 substrate. The sensor is meticulously designed to resonate at 2.746 GHz, exhibiting a reflection coefficient of −38.54 dB. Its temperature-sensing capabilities span the frequency range of 2.0-3.6 GHz. Employing Nitinol as the sensing material, the sensor responds to temperature-induced deformation, resulting in a discernible shift in the resonant frequency and a concurrent reduction in the reflection coefficient amplitude. This innovative sensor presents a compelling solution for temperature-sensing applications, as evidenced by a calibration curve derived from data, illustrating a consistent linear correlation between temperature and reflection coefficient amplitude. The comprehensive simulation and analysis of the chipless RF sensor were executed using CST Microwave Studio for simulation and CST MPhysics Studio for in-depth analysis.