An apparatus for low-frequency signal detection and transmission in a short-distance communication field comprises: a PCB, a magnetic induction module for inducing low-frequency magnetic signal, and a low-frequency signal processing module for detecting low-frequency signal, the magnetic induction module and the low-frequency signal processing module being integrated onto the PCB. One example method may include determining a location of the mobile station, and determining data that is accessible to the mobile station based on its location. The motion estimator assumes that motion is constant between fields. Each of the planar Schottky diodes further includes a Shannon implant region disposed in a gap between the separated body regions of two adjacent power transistor cells for further adjusting a leakage current of said Schottky diode. Several tests are provided and the user is allowed to choose which tests are to be used.