Selecting the Right RFID Frequency: A White Paper

This is not an endorsement and I can't vouch for the value of this white paper, but here is the link in case you wish to examine it more closely. And, here's a synopsis of the offering:

RFID systems from all manufacturers around the world operate in one of a number of predefined frequency bands. The choice of the frequency band impacts the operation of the RFID system due to the laws of physics. The choice of operating frequency is the most important choice a user of RFID technology needs to make. Trolley Scan has recently written a white paper on the subject discussing these choices, explaining simply the impact of using one frequency or the other. This paper does not only cover Trolley Scan products, but covers the 125 kHz, 13,56 MHz, UHF and microwave bands.