Composition Of RFID

1. RFID tags (radio frequency cards): RFID tags are commonly known as electronic tags, also known as tags, transponders, and responders. They can be divided into active (active) and passive (passive) types according to their working methods. Passive RFID tags have close reading and writing distances and low prices; Active RFID tags can provide longer read and write distances, but require battery power and are more expensive. Passive RFID tags consist of a tag chip and a tag antenna or coil. They utilize the principle of inductive coupling or electromagnetic backscatter coupling to achieve communication with readers and writers. RFID tags store a unique code, usually 64 bits, 96 bits, or even higher. Its address space is much higher than the space provided by barcode, so it can achieve single item coding. When an RFID tag enters the functional area of the reader/writer, it can generate an induced potential difference at both ends of the tag antenna according to the inductive coupling principle (within the near-field functional area) or the electromagnetic backscatter coupling principle (within the far-field functional area), and form a weak current in the tag chip path. If the current intensity exceeds a threshold, the RFID tag chip circuit will be activated to work, Thereby performing read/write operations on the memory in the tag chip, and the microcontroller can further add complex functions such as passwords or anti-collision algorithms. The internal structure of RFID tag chip mainly includes four parts: RF front-end, analog front-end, digital baseband processing unit, and EEPROM storage unit.
2. Reader/Writer: A reader/writer, also known as a reader or interrogator, is a device that performs read/write operations on RFID tags. It mainly includes two parts: a radio frequency module and a digital signal processing unit. The reader/writer is the most important infrastructure in the RFID system. On the one hand, the weak electromagnetic signal returned by the RFID tag enters the RF module of the reader/writer through the antenna and is converted into a digital signal, which is then processed and reshaped by the digital signal processing unit of the reader/writer, and then the returned information is retrieved from it to complete the identification or read/write operation of the RFID tag; On the other hand, the upper layer middleware and application software interact with the reader and writer to implement the execution of operating instructions and data aggregation and uploading. When uploading data, readers and writers will perform de duplication filtering or simple conditional filtering on RFID tag atomic events, process them into reader and writer events, and then upload them to reduce the flow of data exchange with middleware and application software. Therefore, microprocessors and embedded systems are also integrated in many readers and writers to achieve some middleware functions, such as signal status control, parity error checking and correction. In the future, readers and writers will exhibit a trend of intelligence, miniaturization, and integration, and will also have more powerful front-end control functions, such as directly interacting with other devices in the industrial field or even acting as controllers for online scheduling. In the Internet of Things, readers and writers will become core devices that simultaneously have communication, control, and computing functions.
3. Antenna: An antenna is a device that enables spatial propagation of radio frequency signals and establishes wireless communication connections between RFID tags and readers. The RFID system includes two types of antennas: one is the antenna on the RFID tag, which has been integrated with the RFID tag. The other is the reader antenna, which can be either built into the reader or connected to the RF output port of the reader through a coaxial cable. Antenna products often use transceiver separation technology to achieve the integration of transmit and receive functions. The importance of antennas in RFID systems is often overlooked. In practical applications, antenna design parameters are the main factor affecting the identification range of RFID systems. High performance antennas require not only good impedance matching characteristics, but also specialized design for directional, polarization, and frequency characteristics based on the characteristics of the application environment.
4. Middleware: Middleware is a specialized software that is message oriented and can accept requests from the application software end, initiate operations on one or more designated readers, receive, process, and return result data to the application software. In RFID applications, middleware can not only shield the reliability and stability issues caused by various business scenarios, hardware interfaces, and applicable standards brought about by the underlying hardware, but also provide cooperation between business information and management information in a multi-layer, distributed, and heterogeneous information environment for the upper application software. The in-memory database of middleware can also filter, aggregate, and calculate reader/writer events based on one or more readers, abstracting business logic information that is meaningful to the application software to form business events to meet retrieval, publish/subscribe, and control requests from multiple clients.
5. Application Software: Application software is a human-computer interaction interface that directly faces the end user of an RFID application. It assists the user in completing command operations on the reader and writer, as well as logical settings for the middleware. It gradually converts RFID atomic events into business events that the user can understand, and uses a visual interface for display. Because application software needs to be specially developed for different enterprises in different application fields, it is difficult to have generality. From the perspective of application evaluation criteria, the user experience on the application software side is one of the decisive factors in determining the success of an RFID application case.