The Evolution of RFID

The full name of RFID is Radio Frequency Identification. It is a wireless communication technology and a type of automatic recognition technology. RFID system is a hardware device based on RFID technology, which uses wireless radio frequency for non-contact bidirectional data communication. It uses wireless radio frequency to read and write recording media (electronic tags or RF cards), thereby achieving the purpose of identifying targets and exchanging data. It is considered one of the most promising information technologies in the 21st century.

 

In 1935, Sir Robert Watson Watt invented radio detection and ranging (radar), which can be considered as the early origin of RFID. The current RFID technology appeared from 1940 to 1950 and was first applied in World War II. Similar technologies were used by the Allies and Germany for identifying enemy and friendly aircraft. Charles Walton designed a portable RFID transmitter in 1973, becoming the RFID holder. The high cost of early RFID greatly hindered its commercial application. With the development of technology, hardware costs decreased, and it was not until 1980 that it began to be commercialized. After many years of continuous improvement, such as research on minimizing RFID, that technology continued to be improved. Hardware further reduces costs. In 2003, the United States announced the first radio frequency identification standard, and now the related production costs have further decreased, and the application fields have gradually increased and enriched.

 

The working principle of RFID

Firstly, we need to know that a complete RFID system consists of three parts: a reader, an electronic tag, and a data management system. Its working principle is that the tag enters the reader's sensing area, and the reader emits a specific frequency of radio wave energy, which is used by the tag's driving circuit to send out the internal data. At this time, the reader sequentially receives and interprets the data, and sends it to the application for corresponding processing.

 

If RFID is classified according to the power supply method, it can be divided into active RFID, passive RFID, and semi active RFID.

1. Passive RFID

Among these types of RFID, passive RFID has the earliest and most mature appearance, and its application is also the most extensive. He can be said to be a passive RFID system. Passive RFID does not have a power source, how can he provide power? In fact, it is through receiving microwave signals transmitted by RFID readers and obtaining energy through electromagnetic induction coils to briefly power itself, thus completing the information exchange process. In addition, his work frequency is mainly at 125KHz, 13.53MHz, etc., and we usually use this type of bus card, second-generation ID card, and cafeteria meal card.

 

2. Active RFID

Active RFID can be said to be active RFID, which has not been popular for a long time compared to passive RFID. However, it has actually existed in our daily lives, such as the electronic toll collection system (ETC) on highways. As the name suggests, active RFID requires external power supply and actively sends signals to RFID readers. Its size is relatively large, but it also has longer transmission distances and higher transmission speeds, some of which can reach up to 100 meters. The frequency of active RFID is mainly in the higher frequency range of 900MHz, 2.45GHz, 5.8GHz, etc

 

3. Semi active RFID

Due to the advantages and disadvantages of both passive RFID and active RFID, passive RFID has a short recognition distance. Although active RFID has a long recognition distance, it requires an external power supply and has a large volume. Due to market demand, this semi-active RFID system has emerged, which comes with a mobile power supply and is usually in a sleep state. It does not work and does not send signals. It is only activated when the tag enters the low-frequency activator range, so it can also be maintained for a considerable amount of time.