A Wide Range Transmission Line Based Linear Displacement Sensor

Accurate displacement measurement is critical for many applications. Recently, a variety of radio-frequency-based linear sensing techniques were introduced. However, the application previously proposed was either not fully demonstrated towards realizing sensor and/or they limited in range to less than 4 cm. This paper introduces characterized wide-range contactless sensor. The consists short-circuited 50 Ω microstrip line and movable current-sensing resonant probe. probe accurately measures sinusoidal magnetic field distribution along transmission from certain distance above it. measured normalized values are mapped using inverse function post-processing stage. technique comprehensively validated simulations measurements compact prototype operating at 727.5 MHz. Furthermore, merits compared widely-accepted variable differential transformer (LVDT) transducer highlighted herein. metrological characterization shows that it offers very wide dynamic 68 mm with standard deviation estimation error 0.09 (0.13% full range). It also outperforms commercial LVDT terms overall accuracy. In general, scalable has theoretical λ/2 making suitable