Open Complementary Split-Ring Resonator for Eye Tracking

This paper presents a microwave planar sensor for eye tracking. The sensor is implemented using coplanar waveguide (CPW) technology and consists of two identical configurations with a pair of mirror-symmetrical open complementary split-ring resonators in each eye corner. The proposed design employs two uncoupled and separate reflection magnitudes for differential modes. Each of the sensors has two resonance frequencies, fL and fH, to detect horizontal and vertical eye sweeping, respectively. When the eye sweeps left to right or up and down, the asymmetrical condition in the paired sensors provides highly useful information for measuring pupil location, namely, the differential reflection magnitude variation. Experimental results using wearable glasses indicate that the sensor can detect relative eye gazes changes from 50 to 130 degrees horizontally (5.96 dB variation) and 40 to 140 degrees vertically (9.63 dB variation). These two eye sweeping direction connect on the central 90 degrees.