| 摘要 |
A reader for an RFID system includes an antenna assembly, a signal driver and a controller. The antenna assembly has an antenna coupled to an antenna tuning circuit which includes a variable capacitance circuit. The signal driver is coupled to the antenna assembly to apply a drive signal to the antenna assembly. The controller is coupled to the antenna assembly to determine a difference between an antenna impedance and a signal driver impedance and to set the variable capacitance at a set capacitance value which reduces the impedance difference.
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