The Basics of RFID Technology

All the wireless communication is based on a basic principle: By attaching an antenna of the appropriate size to an electrical circuit, the electromagnetic waves can be broadcast efficiently and received by a receiver some distance away. We focus on the characteristics of radio waves over a relatively short distance.

The properties of radio waves are frequency dependent. At low frequencies, radio waves pass through obstacles well, but the power falls off sharply with distance from source. Radio waves are also subject to interference from a variety of sources, from sun spots to other electrical equipment. Due to these reasons there are stringent regulations from government. At this moment if RFID sounds alien to you consider this RFID works on the same principle and similar bandwidth as used by cordless phones, garage door openers, wireless hi-fi speakers, security gates.

ELECTROMAGNETIC SPECTRUM

CLASSIFICATION OF RFID TECHNOLOGIES
LOW-FREQUENCY	LOWFID	125–134.2 KHZ AND 140–148.5 KHZ
HIGH-FREQUENCY	HIGHFID	13.56 MHZ
ULTRA-HIGH-FREQUENCY	ULTRA-HIGHFID OR UHFID	868–928 MHZ

Low FID tags and High FID tags can be used globally without a license. Ultra-High FID tags cannot be used globally as there is no single global standard. In North America, UHF can be used unlicensed for 902–928& MHz (±13 MHz from the 915 MHz center frequency), but restrictions exist for transmission power. In Europe, RFID and other low-power radio applications are regulated by ETSI recommendations EN 300 220 and EN 302 208, and ERO recommendation 70 03, allowing RFID operation with somewhat complex band restrictions from 865–868 MHz, The North American UHF standard is not accepted in France as it interferes with its military bands. For China and Japan, there is no regulation for the use of UHF. Each application for UHF in these countries needs a site license, which needs to be applied for at the local authorities, and can be revoked. For Australia and New Zealand, 918–926 MHz are unlicensed, but restrictions exist for transmission power.