Wireless Passive Intracranial Pressure Sensor Based on Vacuum Packaging

This paper presents a wireless passive pressure sensor based on a pressure-sensitive capacitor specifically designed to monitor intracranial pressure (ICP) in patients with traumatic brain injuries. It is crucial that temperature will affect the accuracy of pressure detection. To improve temperature stability, the capacitor is composed of an SOI wafer as the sensing element and a glass cap for vacuum packaging. To realize reliable vacuum packaging, it is vital to transfer the electrical signal out of the vacuum cavity. The experimental results show that the proposed sensor demonstrated averaged pressure sensitivity and averaged temperature sensitivity of 0.5803 Hz/kPa and 0.024 Hz/°C. Additionally, the in-vivo test in the animal show that the proposed sensor has the similar detection effect with the commercial wired sensor, and naturally has the advantage of reducing the risk of infection, which further validated the feasibility and effectiveness of the wireless passive ICP monitoring system.