What is RFID?
Radio Frequency Identification (RFID) refers to a technology by which a reader captures digital data encoded in an RFID tag or smart label (defined below) via radio waves. RFID has a wide range of uses, from public transportation to animal identification to product tracking. In industrial environments, RFID tags are used to track parts or assets and can be used for automation and/or logistical purposes.
What is RFID Frequency?
There are 3 RFID frequencies to choose from: LF, HF and UHF. You may recognize the term radio transmission, and the two technologies do have a lot in common. As with radio transmissions, it is important to tune RFID tags and their readers to the same frequency.
If the RFID tag and the reader use different languages, the results will be much the same. This is why frequency selection is so important, and how getting it right is critical to the success of any RFID implementation.
Types of RFID Tags
There are three types of RFID tags: Active, Semi-Active (or Battery-Assisted Passive), and Passive.
Active RFID tags have a transmitter and their own power source (typically a battery). The power source is used to run the microchip’s circuitry and to broadcast a signal to a reader (the way a cell phone transmits signals to a base station).
Passive tags have no battery. Instead, they draw power from the reader, which sends out electromagnetic waves that induce a current in the tag’s antenna.
Semi-passive tags use a battery to run the chip’s circuitry but communicate by drawing power from the reader. Active and semi-passive tags are useful for tracking high-value goods that need to be scanned over long ranges, such as railway cars on a track, but they cost more than passive tags, which means they can’t be used on low-cost items.
Read-write distance of RFID tags in different frequencies
Low-Frequency RFID TAGS
Low-frequency RFID has the shortest read distance of about 10 cm between the reader and the tag. After special tag design and reader, the read distance can reach 1.5m.LF read time is slower, however, low frequency is subject to metal and water interference is so the least of the frequency. LF covers a range from 30 to 300 kHz. Due to differences in frequency and power levels around the world, LF is also not considered globally compatible. Common uses of low-frequency RFID include animal tracking and access control.
High-Frequency RFID TAGS
High-frequency RFID is very common and operates in the frequency range of 3 to 30 MHz. reading distances range from 10 cm to 1 meter. Most HF RFID devices operate at 13.56 MHz, and typically NFC is also in the 13.56 MHz frequency band.
Some uses of HF RFID involve near-field communication (NFC), which focuses on data transfer between two devices. This is often found in smart payment cards and other proximity-activated devices. Other industries that use HF RFID for payment, cataloging, and/or tracking include marketing, waste management, automation, health and medical, and manufacturing.
HF RFID tags come in many shapes and sizes to suit many specific purposes. They can accommodate read-only, write-only, and rewritable RFID tags. The memory capacity of the reader ranges from 64B to 32KB.
UHF RFID Tags
UHF RFID tags have the fastest read speeds and longest read ranges. While proximity UHF tags are an option, proximity UHF tags have a shorter and narrower read range than HF tags. However, proximity UHF tags are less susceptible to interference and offer performance advantages.
Long-range UHF RFID tags have a read range of up to 12 m, while active tags can have a read range of 100 m or more. UHF RFID tags operate at frequencies ranging from 300 MHz to 3 GHz, and UHF tags are most susceptible to interference. To resist signal interference, UHF tag manufacturers often build readers and antennas to maintain reliability in troublesome environments.
UHF tags are cheaper to make than HF tags (~5-15¢ labels compared to 50¢-$2), causing them to appear in a wide variety of applications including inventory management, anti-theft management, and wireless device configuration.
RFID technology is a growing market, and UHF tags are becoming increasingly popular due to their lower cost and equivalent effectiveness to LF and HF tags. If you are searching for a new tagging or tracking system that will improve your business model, RFID may be a valuable option to consider.