What is RFID (Radio Frequency Identification)?
RFID (Radio Frequency Identification) specifies the contactless data exchange between RFID transponders and RFID writer/reader devices. The RFID writer/reader device creates a magnetic or electromagnetic field for data transmission purposes that powers the RFID transponder. Data can be exchanged as long as the RFID transponder remains within the electromagnetic field of the RFID reader device. Information can be read from the chip of the RFID transponder, or new data can be stored on the chip.
How are RFID transponders constructed?
Basically, RFID transponders are available in almost all forms, materials, sizes and colors. How they are constructed depends on how they are used and what they are said to serve. A common feature of all the different RFID transponders is that there are two components. Internally, each RFID transponder consists of at least a microchip and a printed, laid or etched antenna. The chip and antenna (also known as the inlay) are very sensitive, which means it has limited resistance to mechanical, thermal and chemical shocks. Therefore, application-specific “packages” of these electronic components become necessary. The simplest form of packaging is an RFID tag. This is sufficient for many applications.
However, with this package, the chip is only protected by a simple foil or paper layer. If you need something more stable and sturdy, we recommend packing the electronics into a laminated card. If this is not enough, especially in the case of industrial applications, the sensitive inlay (= chip + antenna) should be cast into the plastic cover, which represents the most robust package, the most durable and the least sensitive.
What are the different frequency bands of transponders in the RFID system?
RFID is divided into 3 different frequencies: LF, HF and UHF
Low Frequency (LF 125kHz)
This freely accessible frequency band is characterized by low transmission rates and short transmission distances. Operating frequencies are not regulated by radio frequencies. The reading distance is generally less than 1m. There are higher inductive coupling power can provide the use of electronic tags. Wireless signals can penetrate water, organic tissue, and wood, among others.
International standards related to low-frequency electronic tags include ISO11784/11785 and ISO18000-2.
The biggest advantage is that when the tag is close to the metal or liquid object, the influence of the tag search is small, and the low-frequency system is very mature, and the price of reading and writing equipment is low.
Disadvantages: The reading distance is short, multi-tag reading cannot be performed at the same time (anti-collision) and the amount of information is low, and the general storage capacity is 125 bits to 512 bits.
- Mainly used in access control system animal chips, car alarms and toys, etc. Although the low-frequency system is mature, the reading and writing system is mature, and the reading and writing equipment is cheap, due to its low resonance rate, the tag needs to make a winding inductor with a large inductance value, and often needs to package off-chip resonant capacitors. The cost of the tag is higher than that of other tags. high frequency band.
- Typical applications for motor vehicles are: Remote Keyless Entry (RKE), Passive Keyless Entry (PKE) and Passive Keyless Start (PKS).
- Typical applications for animals and livestock are: animal identification, animal husbandry, livestock rearing and cold chains.
- Typical applications for commercial and industrial use are: store alarm anti-theft systems (EAS), industrial laundry, pallet monitoring in commercial transport, container identification (eg: butane gas tanks), tool identification (eg: hospital trolleys)20 Inch container monitoring, luxury monitoring and casino chip monitoring, etc.
- Typical applications for the public domain are: tree monitoring in Paris (watering of health conditions) access control in high security areas such as airports, library inventory and membership card records, etc.
High frequency (HF 13,56 MHz)
HF can be used universally and is characterized by high transmission rate and high beat frequency. The corresponding RFID transponders operate at the HF frequency of 13.56 MHz – a short wavelength that requires only a few antenna windings. Therefore, the RFID antenna can be smaller and simpler.
This is the most typical high-frequency working frequency of RFID, and the relevant international standards are ISO14443, ISO15693 and ISO18000-3. This band is used worldwide as the ISM band. High clock frequency to implement cryptographic functions or use a microprocessor. The data transmission is fast, the typical value is 106Kbit/s.
Electronic tags are generally made into standard card shapes. The electronic label of this frequency band is the most used electronic label in practical applications.
The tags in this frequency band are still mainly passive, and energy supply and data transmission are also carried out through inductive coupling. The largest application in this frequency band is the well-known contactless smart card.
Compared with low frequency, its transmission is faster, usually more than 100KBS, and it can perform multi-label identification (each international standard has a mature anti-collision mechanism). The system in this frequency band benefits from the application and popularization of contactless smart cards, the system is relatively mature, and the price of reading and writing equipment is low.
High-frequency products are the most abundant, with storage capacities ranging from 128 bits to more than 8K bytes, and can support high security features, from the simplest write lock to encryption, and even encryption co-processors are integrated. Generally used in identity recognition, library management, product management, etc.
- Typical applications for contactless smart cards are: e-wallets (school canteens, city bus cards, e-train tickets), access control (stadium tickets, nuclear power plant access) and automatic fare collection systems (AFC) for road transport.
- Used for personal and official data: passports, electronic visas, resident ID cards (my country’s resident ID cards use this frequency band) and driver’s licenses, etc.
- Sentence applications that use dry monitoring and tracking include Parcel monitoring (foreign DHL FedEx) fleet management (monitoring postal vehicle company trucks)
- Book management (document management, book shelving, book inventory) and store monitoring (anti-theft monitoring EAS, flow control, inventory), etc.
Ultra High Frequency (UHF 860 – 950 MHz)
These systems do have very high transfer rates and ranges. Due to the shorter wavelength, dipoles are sufficient as antennas rather than reels, and in the case of ray optics, field expansion is sufficient, which in turn provides targeted expansion.
This frequency band is the main frequency band for realizing the Internet of Things, mainly using passive tags, suitable for applications from 4m to 7m, and can be extended to 10mde applications at most.
860MHz~960MHz is the communication frequency between the second generation PC tag and the reader described by the EPCGen2 standard. The EPCGen2 standard is the most important RFID standard of EPC global. Different regions of the world have allocated the frequency spectrum of this frequency band for UHFRFID. The reader of the Gen2 standard can meet the requirements of different regions:
|North America||902-928Mhz||4W ERP|
|South Korea||910-914Mhz||4W ERP|
Typical applications are: EPCGen2 tags, my country’s railway number automatic identification system (ATIS), store alarm anti-theft system (EAS), supply chain management, postal parcel identification, container management and airport luggage classification. EPCGen2 tags are expected to replace barcode applications that are used in the millions per day, billions per year, and are disposable for applications in luggage, supply chain management, and transportation, among others.