Abstract: A near field communications (NFC) device is disclosed that interacts with other NFC devices to exchange information and/or data. An antenna receives an input signal from another NFC device and a communication circuit processes the input signal. A signal detector may be used to detect an input current signal corresponding to the input signal received from the other NFC device. The signal detector can include a primary communication path and a secondary communication path. Through its proximity to the secondary communication path, the primary communication path induces the input current signal in the secondary communication path.

Abstract: An apparatus and method is disclosed to control antenna characteristic of a near field communications (NFC) device. The apparatus and method may tune a resonant frequency of an antenna module of the NFC device to compensate for manufacturing tolerances of the antenna module. The NFC device may cause the antenna module to operate in a first configuration for a first period of time that is characterized by a compensation resonant frequency and a second configuration for a second period of time that is characterized by an actual resonant frequency. The NFC device causes the antenna module to continuously switch between the first configuration and the second configuration such that on average, a resonant frequency of the antenna module is approximately equal to an expected resonant frequency of the antenna module.