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13.56 MHz RFID Switches

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rsocor01

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Hi all,

I have an array of 16 antennas (coils) that I would like to multiplex using some kind of analog switches or multiplexers. I'm using the Seeedstudio NFC RFID module and it works fine with one antenna connected to it.

I have tried using the LCA110 MOSFET optocouplers, but it works okay only for a few antennas (3 or 4). Somehow, when I add more antennas it stops working, and I don't know why :?:. Any help would be greatly appreciated.

Thank you,

Robert
 

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Hard to guess without seeing your actual circuit.

The fact that you are using a high voltage analog switch suggests that you are multiplexing the RFID coil behind the matching network. But the switch has considerable capacitance, this can't work without tuning/redesigning the matching network.

A more promising approach might be to use individual matching networks for each coil and perform the multiplexing with low resistance, low voltage switches at the reader IC interface.
 

rsocor01

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FVM,

Thank you for your help. We have a four by four antenna array with 16 coils in it. Our goal is to use 4 switches on two sides for a total 8 switches to control the 16 coils. We want to use the matching network that comes in the Seeedstudio NFC RFID module. I think that 8 relays will work for this purpose but we want to use some solid state kind of switch. Any suggestions? Do you think that the MASW-007813 will work? Any other suggestions?

We are controlling the switches with a microcontroller.

Thank you,

Robert
 

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