A Highly Sensitive Substrate-Integrated Waveguide Rotation Sensor With Embedded Reference Band for Calibration

A novel dual-band half-mode substrate integrated waveguide (SIW) sensor is presented to measure rotation while featuring a reference band for calibration purposes. The sensor has two layers: a stationary bottom layer, which consists of a half-mode SIW structure that incorporates three slots, and a rotatable top layer. The first resonance (f1) appears at 2.4 GHz and remains stable to serve as a reference point, while the second resonance (f2) shifts from 3.42 to 4.24 GHz as the top layer rotates from 0° to 90°, with a sensitivity of 9.1 MHz/°. The difference between these two resonances (Δf=f2-f1) directly reflects the rotation angle and effectively compensates for influences that cause simultaneous shifts in both resonances. This compensation principle is demonstrated by temperature analysis. The measured results indicate that the frequency difference remains constant over a wide temperature range from −60°C to 60°C, as temperature affects both frequencies in a similar manner. This confirms that the use of the frequency difference effectively suppresses common-mode frequency drifts, rendering Δfinsensitive to these effects and allowing for reliable detection. An extensive performance comparison with state-of-the-art rotation sensors confirms that the proposed design offers higher sensitivity and reliable dual-band operation with built-in calibration.