By now you have hopefully learned that the voltage induced in a coil is proportionate to the change of the flux threading through that coil. We will now see that this is the cornerstone operating principle for another electromagnetic device called the transformer.

Magnetic Tuning of Resonant Sensors and Methods for Increasing Sensitivity explains methods for better tuning of resonant magnetic sensors typically used with RFID (RF Identification) and PKE (Passive Keyless Entry) devices.