Substrate Integrated Waveguide Derived Novel Two-Way Rotation Sensor

A novel two-way rotation sensor is proposed in this work deploying substrate integrated waveguide (SIW) for the first time instead of traditional microstrip and coplanar waveguide. The SIW is designed for the fundamental TE$_{\sf 10}$ propagation mode with the cut-off frequency at 3 GHz. The designed rotation sensor is comprised of a stator which in this case is the SIW itself with a circular metallic disc etched from the top of it. The other part of the sensor is its rotor which is made of a circular cylindrical disc to be mounted over the stator and with the same diameter as that of the etched part of stator. The top and bottom surfaces of the rotor are having complimentary split ring resonator (CSRR) etched on it which causes a resonance dip to be introduced in the passband of the SIW at a frequency of nearly 6.5 GHz when the CSRR is aligned with the propagation direction of the SIW. As the rotor rotates in either the clockwise or counter-clockwise direction, the resonance frequency starts shifting along with the decrease in the notch dip indicating reduction in coupling. The proposed rotation sensor is exhibiting a wide dynamic range till 90° along with high linearity from 0° - 80°. The sensitivity of the sensor in terms of resonance frequency is 5 MHz/° while 0.21 dB/° in terms of notch dip magnitude. A detailed comparison with the available literature confirms that the proposed rotation sensor provides quite high sensitivity with a high linearity.