Packaged Microwave Displacement Sensors With Wideband Filtering Function

In this letter, a novel packaged linear displacement sensor integrated with inherent bandpass filter (BPF) is presented. The proposed filtering sensor is composed of a multimode resonator (MMR) and a pair of transmission line. Based on the insertion phase shifts, a displacement sensing function can be obtained along with a wideband bandpass filtering response. For verification, a prototype is simulated and measured. The measured results of the proposed sensors are in good agreement with the simulated ones, exhibiting an average phase sensitivity about 14°/mm with a wideband Chebyshev bandpass filtering response centered at 3.2 GHz of 56.7% 3-dB fractional bandwidth (FBW).