A capacitive air touch sensor system in 65nm CMOS technology

In this thesis, the new methodology of an oscillator-based capacitive air touch sensor system is introduced for future touch screen technology. This high sensitivity and low power solution is based on oscillation frequency shifts for air touch screening position identification with improved touch sensitivity and extended reliability. This system includes two parts: first, analog circuits are used to sense signals from the antenna, and then digital circuits are used to determine and analyze the detected human's finger positions.The system is designed and implemented using a 65nm CMOS technology. It is capable of detecting up to 20fF capacitance difference, which is 50 times more sensitive than current projected-capacitive touch screen products. With fixed 1V supply voltage, the power of the entire system is only 1.3mW. The core size is 1mm by 1.2mm, which is compact enough to be adopted in any commercial products.