1. Low Frequency (125 kHz to 134 kHz)

a. Transponders (tags) operating in the low-frequency (LF) range typically function between 120 kHz and 134 kHz; Texas Instruments (TI) devices, for instance, operate at 134.2 kHz. The wavelength in this frequency band is approximately 2,500 meters.

b. With the exception of metallic materials, LF signals can generally pass through most objects without a reduction in read range.

c. There are no specific global regulatory restrictions for LF readers.

d. LF products come in various packaging formats. While high-quality packaging can be expensive, it often ensures a service life of over 10 years.

e. Although the magnetic field strength in this frequency range drops off rapidly, it is capable of creating a relatively uniform read/write zone.

f. Compared to RFID products in other frequency bands, the data transmission rate in this band is relatively slow.

g. Transponders in this frequency range are generally more expensive than those in other bands.

2. High Frequency (Operating frequency: 13.56 MHz)

a. The operating frequency is 13.56 MHz, which corresponds to a wavelength of approximately 22 meters.

b. Except for metallic materials, signals at this frequency can pass through most substances, though this often results in a reduced read range. Transponders must be kept at a certain distance from metal objects.

c. This frequency band is recognized globally and is not subject to any special restrictions.

d. Transponders in this range typically take the form of electronic tags (labels).

e. Although the magnetic field strength in this frequency range drops off rapidly, it is capable of creating a relatively uniform read/write zone.

f. These systems feature anti-collision capabilities, allowing for the simultaneous reading of multiple electronic tags.

g. Specific data can be written onto the tags.

h. The data transmission rate is faster than that of LF systems, and the cost is relatively affordable.

3. Ultra-High Frequency (Operating frequency: 860 MHz to 960 MHz)

a. Definitions for this frequency band vary globally: in Europe and parts of Asia, it is defined as 868 MHz; in North America, it spans 902 to 905 MHz; and in Japan, the recommended range is 950 to 956 MHz. The wavelength in this band is approximately 30 cm.

b. Currently, there are varying standards for power output in this band (4 W in the United States and 500 mW in Europe). It is possible that the European limit will be increased to 2 W EIRP.

c. Radio waves in this frequency band cannot easily penetrate many materials—particularly water, dust, fog, and other suspended particulate matter. Unlike high-frequency (HF) RFID tags, tags operating in this band do not necessarily need to be kept away from metal surfaces.

d. RFID tags in this band typically feature long, strip-like antennas. These antennas can be designed with either linear or circular polarization to suit different application requirements.

e. While this band offers a good read range, it is difficult to precisely define the specific reading zone.

f. It supports a very high data transmission rate, allowing for the reading of a large number of RFID tags within a very short period.

An RFID system consists of at least two components: an electronic tag and a reader. The electronic tag serves as the data carrier for the RFID system and is composed of a tag antenna and a dedicated chip. Based on their power supply method, electronic tags are classified into active tags, passive tags, and semi-passive tags. Active tags contain an internal battery, passive tags do not, and semi-passive tags rely partially on an internal battery for operation.

Electronic tags can also be categorized by frequency—such as low-frequency (LF), high-frequency (HF), ultra-high-frequency (UHF), and microwave tags—or by their physical form factor, including credit-card-style, linear, paper-based, glass-tube, circular, or other specialized, custom-shaped tags.

An RFID reader (or interrogator) communicates wirelessly with RFID tags via an antenna, enabling the reading or writing of identification codes and data stored in the tag's memory. A typical reader comprises a high-frequency module (transmitter and receiver), a control unit, and an antenna.

1: Rapid Bulk Scanning with UHF RFID Readers

While a barcode scanner can only process one barcode at a time, a UHF RFID reader can identify and read multiple UHF RFID tags simultaneously.

2: Miniaturization and Diverse Forms of RFID Tags

RFID technology is not constrained by the size or shape of the tag; it does not rely on fixed dimensions or specific print quality—as barcodes do—to ensure accurate reading. Furthermore, RFID tags can be designed in various miniature forms to suit a wide range of products.

3: Resistance to Contamination and High Durability

Traditional barcodes are typically printed on paper, making them highly susceptible to damage or contamination. In contrast, RFID tags are highly resistant to substances such as water, oil, and various chemicals. Additionally, because barcodes are often affixed to plastic bags or outer cardboard packaging, they are prone to physical wear and tearing; RFID tags, however, store data within a chip, protecting it from such damage.

4: Reusability of RFID Tags

Unlike barcodes, which cannot be altered once printed, the data stored on an RFID tag can be repeatedly added to, modified, or deleted, allowing for convenient information updates.

5: Penetrative and Unobstructed Reading

RFID technology can communicate through non-metallic or opaque materials—such as paper, wood, and plastic—even when the tag is covered or concealed. Barcode scanners, by contrast, require a clear, unobstructed line of sight at close range to read a barcode.

6: Large Data Storage Capacity

A one-dimensional (1D) barcode has a capacity of 50 bytes, while a two-dimensional (2D) barcode can store between 2 and 3,000 characters. RFID tags, however, can store several megabytes of data. As memory technology advances, this capacity continues to grow. As the volume of data required for individual items increases, so too does the demand for tags with greater storage capacity.

7: Security

Because RFID tags carry electronic information, the data can be protected by passwords, making it difficult for the content to be forged or tampered with.

The Electronic Product Code (EPC) is designed as a universal identifier that provides a unique identity for every physical object anywhere in the world, for all time. Stored on an RFID tag, EPC can be associated with dynamic data, such as the origination point of an item and the date of its production, to identify a specific item in the supply chain.

Failure to read ultrahigh-frequency (UHF) tags happens more frequent than to read high-frequency (HF) and low-frequency (LF) tags, since UHF has a longer read range and utilizes a different means of tag-reader communication.

In UHF RFID systems, there can be null spots or dead zones in the read field in which tags cannot be energized. Please properly place the tags or move your reader so that all tags can be read.