Two-dimensional linear displacement microwave sensor based on split ring resonator

A two-dimensional linear displacement microwave sensor based on split ring resonator (SRR) is designed in this paper using microwave technology to measure displacement. The sensor is composed of a stator and a mover. The stator is composed of two groups of SRRs with different sizes coupled with a transmission microstrip line. The mover is made of FR-4 dielectric substrate with single copper coating. When the mover moves in two dimensions, the resonant frequency of the two SRRs will change, and the transmission zero will also shift accordingly, thus establishing the relationship between the displacement and the transmission zero. In addition, the detection sensitivity is improved by loading the defect structure on SRR. Through electromagnetic modeling and simulation, the sensor produces two transmission zeros in the range of 1 GHz to 3.2 GHz, which can characterize the displacement of 0~6 mm in the x and y directions, and the sensitivity is 122 MHz/mm and 82 MHz/mm, respectively. The sensor is fabricated and tested, and the measured and simulated data are basically consistent, which confirms the effectiveness of the sensor design.