There are a variety of frequencies used with radio frequency identification systems.
• Passive low-frequency (LF) systems employ 125 kHz and 134 kHz. LF systems are used for animal identification, access control and some industrial applications.
• Passive high-frequency (HF) systems utilize 13.56 MHz. These are used mainly for access control, smart cards and item identification.
• Passive ultrahigh-frequency (UHF) systems employ 856 MHz to 960 MHz. These systems are used for inventory tracking, item identification and other applications.
• Most active RFID systems utilize 433 MHz, 900 MHz or 2.45 GHz.
Each frequency has its own pros and cons, depending on the application. HF, for instance, has good penetration of materials and a well-defined read field, but the read range is not as long as that found with UHF. On the other hand, UHF has a longer read range but is absorbed by water, which can cause problems when reading tags on items with a high liquid content.
A good system integrator can help you choose the proper system for your application, and work around any challenges that the physics of a specific frequency might raise.
—Mark Roberti, Editor, RFID Journal