SECURE PASSIVE WIRELESS SENSOR AND RELATED METHODS

A passive wireless sensor may be wirelessly coupled with an interrogator. The sensor uses multiple antennas to receive an interrogation signal from the interrogator and compares a path length difference between the signal received at each antenna. The path length difference changes based on the relative position of the sensor and interrogator. Using the path length difference, the sensor transmits a response signal to the interrogator. The interrogator analyzes the response signal to determine sensor position. The interrogator compares the determined sensor position to a previous known sensor position to determine if an attack has occurred, such as a replay, counterfeit, or tampering attack. The sensor may include cryptographic circuitry that scrambles the response signal, thwarting an attack such as a sniffing attack. The interrogator may include multiple antennas and determine a position of the sensor by calculating an angle-of-arrival that enhances a signal from the sensor, via beamforming.