Sensitivity Evaluation for Refection Phase Measurements of Resonant Microwave Near-Field Sensors with Artificial Transmission Lines

摘要

In this contribution, we present a design process to increase the dielectric sensitivity of resonant microwave near-field sensors based on artificial transmission lines to detect small relative permittivity variations down to approximately 0.1 ppm with reflection phase measurements. To support the theory and to achieve an applicable sensor design, circuit and three-dimensional electromagnetic field simulations with AWR and CST Microwave Studio are performed. Moreover, measurements of a realized prototype sensor, that operates at multiple frequencies in the range of 5 to 6 GHz, confirm the design process. In addition, measurements inside a pressure chamber, that produces small pressure and thus midget permittivity variations, state the excellent sensitivity of the sensor.