HID Global Corporation SE3210 사용자 설명서
7.1.1 Inductive Coupling
An inductively coupled transponder usually consists of a single chip and an attached coil,
which is used as an antenna.
Most inductively coupled transponders are passive, meaning that power is supplied by the
Most inductively coupled transponders are passive, meaning that power is supplied by the
reader. To this end, the reader produces a magnetic field that the transponder uses for
power.
Figure 12: Inductive Coupling Principle
Mathematically, treat the coupling as a simple alternating magnetic field. The wavelength at
Mathematically, treat the coupling as a simple alternating magnetic field. The wavelength at
the frequencies of interest is much higher than the distance between the tag and reader (22.1
m at 13.56 MHz). Both antenna coils (transponder and reader) have a parallel capacitor,
creating a parallel resonant circuit. The capacitor is chosen to achieve a resonance frequency
near the working / carrier frequency of 13.56 MHz.
Interpret the arrangement of the two coils as a loosely coupled transformer, with a coupling
Interpret the arrangement of the two coils as a loosely coupled transformer, with a coupling
factor that varies with position and geometry.
Figure 13: Mutual Inductance between Reader and Transponder Antenna