| 英文摘要 | Radio Frequency Identification (RFID) is a kind of automatic identification technology based on non-contact RF principle. Recently, the research and application of RFID develop rapidly, by for UHF band backscatter modulation technology. Key components of RFID systems, which include the test system and relevant antennas, are studied in this paper. The major contents are as follows. First, we analyze systematically the operating mechanism and characteristics of RFID reader and tag, and then elaborate current test technologies. Issues for RFID test have been stated in this paper. Take the RFID application in tobacco manufacturing for an example. Network deployment and programming for reader antenna, as well as formalized deployment are studied. The criterion for the selection of HF or UHF band is discussed. Comparison of various anti-collision algorithms is indexed, and an advanced algorithm of self adapting appears in this paper. We systematically study the methods for test of tag, including sensitivity test, readability rate, differential Radio Cross Section (ΔRCS) and related tests. For the tests, we develop a chamber for imitation of free space, and key technical indexes can be found in this paper. Second, this paper focuses on the test methods for RFID antennas. For 50 Ohm impedance port antenna, ones of testing for gains are given by absolute and relative methods, in addition to radiation pattern. RFID-oriented test method, named by equivalent power line pattern is given in this paper, along with the automatic test equipment. This method can be used to direct the deployment of RFID reader antennas in reality. RCS is closely interrelated to the range of RFID tag, especially for passive one. Sweep-frequency technique directly acts on the site and time for RCS. Relative RCS test technologies are included in this paper. In addition, oriented to complex impedance of tag antenna, this paper describes methods for measuring it, by direct manner, mirror method, comparison, indirect process and testing jig. Through some of these methods, the complex impedance test may be available to employ. Third, in connection with requirements for characters of RFID antenna, this paper states several design methods for tag antennas with high qualities, such as insensitive to metal environment and surroundings, omni directivity, robust, high radiation efficiency, muliti-frequencies and miniaturization. For insensitive to surroundings, many methods are provided: ferrite c... |
修改评论