In wired communication systems the physical wiring constraints allow communication links and networks to be effectively isolated from each other. The approach that is generally adopted for radio frequency communication channels is to separate on the basis of frequency allocation. This requires, and is generally covered by government legislation, with different parts of the electromagnetic spectrum being assigned to different purposes. Allocations may differ depending on the governments concerned, requiring care in considering RFID applications in different countries. Standardisation efforts are seeking to obviate problems in this respect.

Three frequency ranges are generally distinguished for RFID systems, low, intermediate (medium) and high. The following table summarises these three frequency ranges, along with the typical system characteristics and examples of major areas of application.

Table 1. Frequency Bands and Applications

A degree of uniformity is being sought for carrier frequency usage, through three regulatory areas, Europe and Africa (Region 1), North and South America (Region 2) and Far East and Australasia (Region 3). Each country manages their frequency allocations within the guidelines set out by the three regions. Unfortunately, there has been little or no consistency over time with the allocation of frequency, and so there are very few frequencies that are available on a global basis for the technology. This will change with time, as countries are required to try to achieve some uniformity by the year 2010.

Three carrier frequencies receiving early attention as representative of the low, intermediate and high ranges are 125kHz, 13.56 MHz and 2.45 GHz. However, there are eight frequency bands in use around the world, for RFID applications. The applications using these frequency bands are listed in Table 2.

Not all of the countries in the world have access to all of the frequency bands listed above, as some countries have assigned these bands to other users. Within each country and within each frequency range there are specific regulations that govern the use of the frequency. These regulations may apply to power levels and interference as well as frequency tolerances.