RFID, or radio frequency identification, is a technology that has enabled businesses around the world to improve their processes in many ways, from their manufacturing operations to their supply chain management and more. The widespread adoption of RFID has also made it possible to reduce costs, easily scale operations, and boost profits at an unprecedented rate. However, maximizing the potential of RFID first requires making the right decisions.
RFID technology uses several different frequencies, and choosing the one best suited for a business’s specific application or processes is vital. Understanding the available frequencies, their capabilities, and limitations is the first step in making the right choice.
The Different RFID Frequencies Explained
Similar to radio transmissions, it is critical to tune RFID tags and their readers to the same frequency. The three main RFID frequencies to choose from are low frequency (LF), high frequency (HF), and ultra-high frequency (UHF). These terminologies are also common in radio transmissions as the two technologies share many things in common.
As one may recall, tuning a radio to switch between stations will only result in static until the next available station is reached. The same applies to RFID, wherein tags and readers not on the same frequency cannot communicate. This is why choosing frequencies is critical, and getting it right is paramount to successful RFID implementation.
Regarding RFID, the difference lies in the nature of the frequency. The operational frequency for RFID applications is as follows:
- LF: 125 kHz and 134.2 kHz
- HF: 13.56 MHz
- UHF: 433 MHz for active tags and between 860-960 MHz for passive tags
Besides establishing communication, it is essential to note that the radio waves enabling RFID technology also have distinct features at different frequencies.
How Frequency Impacts Decision-Making Around RFID
The best choice of frequency largely depends on the assets being tracked or manufactured. Below, we take a deep dive into the capabilities of each frequency.
- Low Frequency
LF RFID is the most mature frequency in use and generally finds use in access control systems, animal tracking and identification, asset tracking, automotive control, healthcare, various point-of-sale applications, and vehicle immobilizers where its short range is a non-issue. LF tags are also ideal for use in manufacturing plants and steel buildings where metallic surfaces abound as they do not suffer from readability issues. Other materials that they work well with include items containing water, liquids, wood, and animal tissues.
LF RFID tags rely on the near-field inductive coupling to power and transmit data to the interrogator. They are passive tags (no embedded power source and transmitter) with a limited read range of just several inches. LF tags have limited to no anti-collision capabilities, making it extremely difficult to nigh impossible to read multiple tags simultaneously. Moreover, LF tags have the lowest data transfer rate out of all frequencies and can only store a limited amount of data.
- High Frequency
HF RFID tags are similar to LF tags in that they are generally passive, have a short range of up to three feet or 1 metre max, have no anti-collision, and use near-field inductive coupling. They also have no issues with the materials mentioned in the previous section save for metals in the vicinity. However, its higher range means it has a higher data transfer rate than LF.
The slight improvements of HF RFID tags make them ideal for applications like tracking patients in hospices, managing access tickets in transit systems, tracking library books, and smart cards and credit cards.
- Ultra-High Frequency
UHF RFID systems usually have a much greater read range of 15 to 20 feet (with some reaching up to 50 feet depending on the installation), making them suited for applications where extended usability range takes top priority. UHF tags use backscatter or far-field radiative coupling, with all protocols having some anti-collision feature, making it possible to read several hundred tags per second. RFID systems operating in UHF can also transfer data faster than LF and HF. However, this extended read range and quicker read rate come at the cost of signal attenuation due to UHF’s shorter wavelength.
UHF RFID systems are typically found in manufacturing plants and large-scale warehouses, environments where efficiency and speed are the most critical factors. They are also used in parking access control and electronic tolls, where their longer range is most useful.
RFID asset tracking systems are tested to increase efficiency, minimize costs, and help organizations improve their operations in countless ways, but only if the correct and proper frequency is implemented which is highly dependent on their usage or application. Each RFID system has specific benefits and drawbacks that business owners must extensively evaluate in order to make the right decision. Understanding the basics of RFID technology and its frequencies makes it easier for businesses to determine which is the perfect frequency for their specific application.