Patent ID: 8917160
Filing Date: 2014-12-23
Classification: G06K,H04B

Abstract:
1. An RFID module comprising: an antenna element forming an RFID antenna; an RFID circuit block to which the antenna element is connected; and a first resonance frequency adjustment circuit having an element that includes a drain terminal connected to the antenna element, a gate terminal that is grounded, a source terminal that is grounded, wherein a pull-up resistor is connected between the drain terminal and a power supply such that the drain terminal has separate connections to the antenna element and to the power supply, wherein a DC level of the drain terminal is configured to be decreased through a capacitance between the drain terminal and the gate terminal when an AC waveform of a predetermined amplitude or more is input on the basis of a voltage excited in the RFID antenna when the RFID module comes close to an R/W device, and the first resonance frequency adjustment circuit is configured to shift a resonance frequency of a loop antenna toward lower frequencies by increasing a drain-source parasitic capacitance value on the basis of the decrease of the DC level of the drain terminal.