Sauce: http:// www.centrenational-rfid.com/rfid-frequency-ranges-article-16-gb-ruid-202.html
The RFID frequency spectrum
RFID is considered as a non specific short range device. It can use frequency bands without a license. Nevertheless, RFID has to be compliant with local regulations (ETSI, FCC etc.)
•LF : 125 kHz - 134,2 kHz : low frequencies,
•HF : 13.56 MHz : high frequencies,
•UHF : 860 MHz - 960 MHz : ultra high frequencies,
•SHF : 2.45 GHz : super high frequencies
Here is a graph of the electromagnetic spectrum with the frequency bands that the RFID systems can use