Interrogation of passive wireless sensors in harsh environments Zusammenfassung: The automotive aerospace and all other applications working in severe conditions require sensing solutions to monitor critical parameters in order to increase the systems lifetime or to reduce power consumption. The sensors must be small robust and exhibit low manufacturing costs. Passive wireless sensors have the advantages that they do not require any battery and they can be interrogated with no physical connection to the reader electronics. This thesis reports the development of different torque and high temperature wireless sensing systems based on sensors initially used for radio frequency signal filtering: Surface Acoustic Wave (SAW) and microwave dielectric resonators. The described coupling methods between the reader antennas and the sensors improve the sensing accuracy resolution interrogation distance and immunity to the environmental clutter currently being the main issues when using these sensors in harsh environments. Based on the piezoelectric effect and the propagated mechanical wave velocity dependence with the environment SAW resonators are used for passive wireless torque or temperature sensing on rotating machinery. However the main source of errors comes from the angular variations of the coupling between the coupler elements and the receiving coupler element impedance. This parasitic frequency shift is known as pulling effect and concerns all measurements using resonators. In this work several wireless coupling solutions for the interrogation of SAW resonators on a clamp system fixed on a small diameter shaft are presented. The maintained solution is a capacitive coupler based on coplanar strip lines. It allows an angular transmission amplitude variation lower than 4 dB and a single 434 MHz resonator angular frequency pulling lower than 200 Hz (0.46 ppm). The RADAR based interrogation Finite Element Method (FEM) simulations coupler parameters and frequency pulling measurement results are presented to demonstrate the performances of the complete sensing system. Dielectric resonators are resilient in harsh environments where SAW sensors suffer from the packaging and the radiating element constraints. In this work the sensitivity of multi mode dielectric resonators over temperature is investigated. The resonance frequency shift is due to the material permittivity change and the thermal expansion. Moreover dielectric resonators are physically connected to metallic surfaces in order to get a sufficient coupling ...