RFID Frequency

cityman1013

Hi everyone.
I have a bunch of RFID tags that I want to use. Unfortunately I don't know what frequency they are. Does anyone know of a product out or plans for one that can detect and display the frequency on the tags? Or a RFID reader that you can manually adjust the frequency so I'll know when it starts reading them?

Thanks

Mike Green

"RFID reader ... manually adjust the frequency" - No. That's not how RFID readers work. They're designed for specific frequency bands. The reader generates a signal at that frequency which is broadcast. The RFID tag is tuned to that frequency and absorbs energy at that frequency. Some of that energy is rectified and filtered to provide power for the controller in the tag. The controller, once powered and initialized, absorbs more energy for short periods of time. This and the normal power draw are the two states used for communications to the reader.

You would need some kind of frequency generator that would generate power at specific frequencies and measure the absorption of energy at a particular frequency, then display both frequency and impedance / power absorption. I'm not aware of any RFID reader built to do this. You'd have to cobble together the necessary instruments or design and build your own. There's very little need for such a setup since RFID tags / readers are specifically chosen for a particular band of frequencies based on the needs of the customer / user. Some bands require larger antennas than others, so the size of the tag and the reader are affected. The range and materials that might affect the readings also can be affected by the frequencies used. Power requirements can be affected.