A passive intraocular pressure sensor and a wireless sensing technique using an intermediate LC resonator

This paper presents a wireless passive pressure sensor and wireless sensing techniques for intraocular pressure (IOP) measurement. The sensor device consists of a capacitor array and a coil inductor, which form a series LC type resonator. The capacitor array is also a membrane structure, and is fabricated by surface micromachining technique. By using a high permeability ferrite coil detector, the IOP sensor can be wirelessly detected up to 4mm with a sensitivity of 3.78kHz/(10mmHg), under a pressure range 0–70mmHg. This work also demonstrates a new sensing technique using an intermediate LC resonator to improve the sensing distance to 1.5cm, with a sensitivity of about 185Hz/(10mmHg).