1. Introduction
RFID (Radio Frequency Identification) is a non-contact automatic identification technology that enables the automatic recognition of objects and the acquisition of related data through radio frequency signals. This system can operate in various harsh environments without requiring manual intervention. An RFID system typically consists of two main components: the reader and the electronic tag. The electronic tag stores data, and when it enters the effective range of the reader, communication occurs based on a specific protocol. RFID technology can recognize high-speed moving objects and multiple tags simultaneously, making operations fast and efficient. Short-range RFID products are resistant to harsh conditions such as oil and dust, making them suitable for replacing barcodes in environments like factory assembly lines. Long-range RFID systems are commonly used in transportation, with recognition distances reaching several tens of meters, such as for vehicle identification or automatic toll collection [6]. Additionally, due to its resistance to counterfeiting and hacking, RFID tags offer strong security. Its applications are widespread, including animal tracking, car alarms, access control, parking management, production automation, and material handling. Countries and international organizations are actively working on developing RFID standards. However, there is currently no comprehensive global standard, with major specifications including EPC in the US and Europe, UID in Japan, and ISO 18000 series standards.
There are various types of RFID tags, classified based on power supply and operating frequency. They can be either active or passive, depending on their power source, and categorized by frequency into low-frequency (134.2kHz), high-frequency (13.56MHz), ultra-high-frequency (433MHz and 915MHz), and microwave (2.45GHz) [6]. While the individual technologies have matured, challenges remain in practical applications within logistics and manufacturing industries, such as cost efficiency, signal interference, improving recognition accuracy, information security, privacy protection, and standardization.
The basic RFID system includes RFID tags, readers, and supporting software. The CC2430 chip provides a powerful integrated development environment and supports interactive debugging using IAR’s industry-standard IDE, which is widely recognized in embedded systems. It operates at 2.4 GHz and is fabricated using a 0.18μm CMOS process, consuming 27 mA during operation and less than 27 mA or 25 mA in receive and transmit modes, respectively. Available in a 7 mm × 7 mm QLP package with 48 pins, all pins are categorized into I/O, power, and control lines. The chip’s sleep mode and quick transition to active mode make it ideal for long battery life applications, particularly in RFID systems. This article uses TI’s CC2430 as the core component for designing active RFID tags. Powered by a button battery with a voltage range of 3.3–4.5V, the chip consumes minimal power, requires few peripheral circuits, and integrates most high-frequency components internally, ensuring stable performance and reduced external interference. It is well-suited for low-power, high-performance applications.
2. Label Hardware Design
2.1 Hardware Circuit Structure
A typical active RFID tag comprises an antenna, a radio frequency module, a control module, memory, a wake-up circuit, and a battery module, as shown in the figure. The RF module handles the modulation and demodulation of signals between the tag and the reader. The controller executes instructions from the reader, while the memory stores tag information and microcontroller programs. The RF module includes both transmitting and receiving sections. The transmitter consists of a modulator, power amplifier, bandpass filter, mixer, and local oscillator, while the receiver includes a low-noise amplifier, bandpass filter, demodulator, and waveform shaper. The TI CC2430 integrates the entire wireless communication system, reducing costs and simplifying design with only a few peripheral components. Fabricated in a 0.18μm CMOS process, the chip consumes 27 mA during operation, with current losses of less than 27 mA or 25 mA in receive and transmit modes. It comes in a 7 mm × 7 mm QLP package with 48 pins, divided into I/O, power, and control lines. The chip’s sleep mode and fast transition to active mode make it ideal for long-lasting battery applications, especially in RFID systems. This design matches the output to a 50-ohm microstrip patch antenna, and surface-mount components are used in the PCB layout, reducing complexity and size. The entire PCB measures 10 cm × 5 cm, meeting the miniaturization requirements of the label. The tag's circuit diagram is shown in Figure 2.
2.2 Low Power Design of Labels
For active tags, battery power limits their operational lifespan, so energy efficiency is crucial. The CC2430 chip, fabricated in a 0.18μm CMOS process, consumes 27 mA during operation and less than 27 mA or 25 mA in receive and transmit modes. By implementing a control program during the design phase, the tag can respond only within the reader’s working range, maximizing energy savings and extending battery life.
2.3 Reader Design
The design of the reader involves selecting appropriate hardware and software to ensure reliable communication with the RFID tags. The reader must support the required frequency band, handle signal processing, and manage data transmission efficiently. It also needs to be compatible with the tag’s communication protocol and capable of operating in different environmental conditions. The choice of components, such as antennas and signal amplifiers, plays a key role in determining the reader’s performance and range. Additionally, the reader should be designed with user-friendly interfaces and robust error-checking mechanisms to enhance overall system reliability.
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