Wireless passive weight sensor: Design and simulation of an RLC-resonance sensor for weight sensing in conveyor belts

This thesis presents a resonant sensor circuit design that converts the deformation of a load cell in a conveyor belt into a change in resonance frequency. The sensor is inductively coupled to a reader circuit using planar PCB inductor coils. A sensor circuit was designed, fitted on a square PCB with 14.14 mm side length. The circuit consists of a planar squared inductor and a planar interdigital capacitor. The inductor has an inductance of 0.66535 $\mu$H, and the capacitor has a capacitance of 5.157 pF. An additional SMD capacitor was added to reach a resonating frequency range around 27.2 MHz. The deformation of the load cell causes a bend in the sensor PCB, which is directly attached to the diaphragm of the load cell. The bend causes a change in capacitance of the interdigital capacitor, which shifts the resonance frequency of the sensor. The sensor components are designed in MATLAB and simulated and verified in CST studio.Bachelor graduation project Electrical EngineeringElectrical Engineerin