Design of H-shaped planar displacement microwave sensors with wide dynamic range

In this paper, two kinds of H-shaped planar microwave sensors are proposed for displacement detection. For the first sensor, the movement of the mover can be retrieved by the resonant frequency shift. The working principle of this sensor is explained using the open stub resonator. Then, the coupled line is employed to realize frequency-splitting sensor, and it is demonstrated that two transmission zeros are caused by even- and odd-mode resonances. The influences of the geometrical parameters on the sensor characteristics are investigated. The proposed sensors are fabricated and tested. The experimental results demonstrate that the proposed sensors exhibit wide dynamic range and good sensitivity. In particular, the proposed sensors achieve about two times larger dynamic range than previous designs.