High-sensitivity micro-magnetic probe for the applications of safety and security

This paper presents a high-resolution near-field magnetic sensing system for nondestructive inspection applications of safety and security. The system includes a probe chip based on a 0.18-μm 5-metal-layer CMOS process technology and a micro-position calibration mechanism. The probe chip includes a magnetic pick-up coil followed by a 3-stage low-noise amplifier to amplify the induced voltage on the coil. A mechanical scanning system with an ability of micro-position calibration is to allow high-precision calibration and micro-scanning operation. For the security application, a high spacial resolution magnetic scanning experiment is conducted on a micro-strip line and on the surface of a cryptographic FPGA running 128-bit Advanced Encryption Standard algorithm. In addition, the magnetic probe is used for safety applications for fault detection in both low-power devices and power electric circuits.