Bistatic Configuration Reading for Sub-Millimeter Displacement Chipless Tag Sensor

A phase measurement technique for millimeter wave chipless tag μ−displacement sensor considering bistatic configuration is presented. For this purpose, a bistatic antenna configuration is employed, where the angle between the incident wave and the backscattered signal is chosen to increase the useful part of the tag signal. The displacements are analyzed along the 1D axis parallel to the alignment of the antennas. The validity and accuracy of the displacement method have been verified by moving the tag to different positions considering static antennas. The measured displacement deviations achieved based on the proposed approach are around 5 μm for a 30 μm step. It indicates precise and low-cost displacement chipless tag sensors for millimeter-wave applications.