Patent ID: 9665820
Date: 2017-05-30
CPC Classifications: G06K,H04B

Claim:
1. A load modulation circuit for radio frequency identification comprising a first load modulation module connected to a coupling circuit, further comprises: a second load modulation module connected to the coupling circuit; under a specific weak field intensity, load modulation is mostly realized by the first load modulation module, with the second load modulation module contributing far less than the first load modulation module to a load modulation waveform and a load modulation depth; as field intensity increases, the first load modulation module contributes less and less to the load modulation waveform and the load modulation depth; while as the field intensity increases, a variable voltage controlling the second load modulation module also increases and the second load modulation module contributes more and more to the load modulation waveform and the load modulation depth under the control of the variable voltage; under a specific strong filed intensity, the load modulation is mostly realized by the second load modulation module, with the first load modulation module contributing far less than the second load modulation module to the load modulation waveform and the load modulation depth.