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Auto-tuned RFID reader antenna

  • US 20070222605A1
  • Filed: 03/22/2006
  • Published: 09/27/2007
  • Est. Priority Date: 03/22/2006
  • Status: Active Grant
First Claim
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1. A reader for an RFID system comprising:

  • an antenna assembly including an antenna tuning circuit and an antenna, said antenna tuning circuit coupled to said antenna and said antenna having an antenna impedance;

    a variable capacitance circuit included in said antenna tuning circuit, said variable capacitance circuit having a variable capacitance;

    a signal driver coupled to said antenna assembly to apply a drive signal to said antenna, said signal driver having a signal driver impedance; and

    a controller coupled to said antenna assembly to determine a difference between said antenna impedance and said signal driver impedance and to set said variable capacitance to a set capacitance value to reduce said difference.

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