Research On Far-distance Contactless IC Card Read-write System At 915MHz

At the present time, close quarters intermediate & low frequency RFID IC read-write system based on inductive coupling load modulated technology is used worldwide. Along with a very fast development of world economy, especially the advancement and popularization of Internet of Things, the requirement of high frequency RFID IC read-write system is becoming increasingly pressing. In our country, the application is still in its primary stage.In the following years of the development of Internet of Things, China will be the maximal EPC consumer. High frequency RFID IC is just the core of EPC technology. Thereby, the research on this thesis is of great significance.This paper touches upon some elementary research work about 915MHz high frequency RFID IC read-write system and parts of the system, including data communication, reader antenna, RF interface, control of the system, etc. The concrete contents are listed as follows:1. To a certain degree, contactless IC card-related standards, theories and its realization technology are guidable and instructive to the development of high frequency RFID IC read-write system and the study of the application system of logistics.2. Base on Bi-phase Space coding principle the program of coding and decoding of 915MHz high frequency RFID IC read-write system is set up.The realization technology of using hardware.3. The ODD and CRC data verifying format are carried out by technology of hardware.4. Analyze the data transmission principle and the antenna receiver/transmitter principle of high frequency RFID contactless IC card system, research into the design principle and methods of antenna and work out four-element half-wave dipole matrix antenna and circle polarization microstrip antenna.5. Adopt zero-IF receiver program to design receiver circuit. Substitute multiplierand voltage comparator for A/D switch circuit in the zero-IF receiver program, therefore, the design is simplified and delicacy of the system are effectively enhanced.6. Accomplish the design of the MCU application system and program its related functional softwares. Succeed in operating it in the system.Being a key part of the project of far distance contactless IC card read-write system, the production of the paper has passed identification by experts, and been successfully applied to logistics, access control system and so on.