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RFID antenna question. Answered

How sensitive is RFID functionality to the length of its antenna?

Specifically, if I had an RFID like this one, cut the antenna and then resoldered it, would the loss in antenna length (I'm guessing about half an inch) affect the workings of the device?

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steveastrouk
steveastrouk

Best Answer 6 years ago

Its more to do with the change in open AREA and any change in the number of turns, not the overall wire length - you aren't making a 1/4 wave dipole for high microwave frequencies.

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Kiteman
Kiteman

Answer 6 years ago

So, if the coil were rewound, with a diameter of, say, an inch, the loss in area would cut its effectiveness?

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steveastrouk
steveastrouk

Answer 6 years ago

This, to my mind, is the go-to paper on the subject
http://ww1.microchip.com/downloads/en/appnotes/00710c.pdf

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Kiteman
Kiteman

Answer 6 years ago

Cool, thanks.

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steveastrouk
steveastrouk

Answer 6 years ago

Yes, although it can perhaps be compensated by the number of turns on the coil.