APPARATUS AND METHOD OF INCREASING THE SENSITIVITY OF MAGNETIC SENSORS USED IN MAGNETIC FIELD TRANSMISSION AND DETECTION SYSTEMS

摘要

The present invention is directed to an apparatus and method of increasing the sensitivity of a magnetic sensor embedded in a key fob used in passive keyless entry and identification systems. The sensitivity of the sensor is increased by magnetically coupling a pair of magnetic flux concentrators at opposite ends of the magnetic core of the sensor, which is surrounded by a helical conductive coil. Addition of the magnetic flux concentrators external to the coil effectively forces a larger window of magnetic flux through the coil than was possible without them. This increases the magnetic sensitivity of the coil as a sensor in a time varying magnetic field. In a key fob/passive keyless device this results in an increased range of operation.