Research Of Low Power RFID Reader On Power Control

RFID (Radio Frequency Identification) technology, radio frequency identification technology, has been widely used because of its characteristic of huge information storage capacity, high safety, non-contact identification. With the rapid development and wide application of this technique, to reduce the power consumption of the reader has become a new hot research.Low voltage chip, intelligent power management circuit and the power adjustable technology can reduce the power consumption of the reader. The low power consumption of the UHF reader is designed by the power-adjustable method. According to the principle of the reader transmitter power can be adjusted according to the distance between the readers to label the distance. The transmitting power and the reading distance is directly related. When the transmit power is large, the reading distance is far. On the contrary, the transmit power is small, the reading and writing distance is nearly.But the general readers’ transmit power is not adjustable on the market. In this way, the transmit power can not be adjustment besead on the distance between the readers and tags.It will cause a waste of electricity. If the transmission power of the RFID reader is adjustable, can not only reduce the power consumption of the reader, but also can improve the system performance of the collision, the anti-interference ability is enhanced, dynamic range compression.This paper presents a design scheme of low power consumption based on reader with automatic power control, according to the distance between the tag antenna and reader antenna to adjust the transmitting power. The system hardware consisted of control module and RF module. The control module was designed by S3C6410. The system hardware also added external storage circuit module, RS-232 serial port module, clock module, power supply module, Ethernet module, liquid crystal display module. The RF module was designed by CC1101 in the study. In addition, in the design of transmission link, the type of amplifier is the gain can be adjustable.The directional coupling geophone increased in the receiving link. So the power can be adjusted in real time to the reader.The system software including the Linux operating system transporting, and the designs of CC1101 driver program, power control program and RF transceiver procedures.System testing and result analysis show that, the average reader read write speed is about 3ms, the reading distance up to 5m. And the transmit power with the knowledge distance adjustable. Maximum power is 33dBm, the minimum transmitting power can be reduced to lOdBm. Power controllable reader not only reduces the power consumption, but also improves the anti collision performance of the system.