Research Of Key Technolgies Based On Saw Rfid-tag

SAW (Surface Acoustic Wave) based RFID (Radio Frequency Identification) tag is a passive and chipless tag. SAW Identification technology is one of RFID technology which is built on the SAW RFID tag system. It has wide potential marketing because of its unique advantage comparing with traditional IC (Integrated Circuit) RFID technology such as wireless, passive and long-term transportation.We introduce principium, configuration, characteristics and some relatively basic theory about SAW RFID tag system and analyze the problems existing in the SAW ID technology which is realized by this system. Especially, we deeply research how to build a SAW RFID tag system. Around this topic, the key technologies of system we discuss are several aspects including coding method of tags, determination of optimal threshold level for ID-Tags, time delay identification and how to build the part of sending and receiving signal and the part of data-collecting system. The main work I have done in the research process is as follows:1. We review briefly the history of SAW technique and introduce its features. Based on working principle of Surface Acoustic Wave RF tags, we introduce the coding methods of RF tags label and how to launch the pulse signal, which is tested through the expriment of the signal waveform.2. Based on the analysis with the parameters of the transmitting/receiving system, we design the cuicirts. After received by the receiving cuicirts, the signal is IQ demodulated by the hardware. The data-collecting block gets the 2 routes of analogue signal through the high speed ADC, and processes the signal with DSP using algorithms such as determination of optimal threshold level for ID-Tags, time delay identification in order to achieve the purpose of identify RFID Tags effectively.3. The design on the CPLD realise the signal transmition from the ADC to the DSP through the dual RAM, which help the system meet diferent needs. This block also controls the system Clock.In this thesis, the innovation is that take advantage of traditional technologies in some other subject fields such as communication and radar. Combine them with Characteristics of SAW RFID tag, we form new algorithm and use them to build SAW RFID system to identify the RFID tags. We analyze the principle of these technologies, validate the practicability of using them to realize and improve SAW RFID tag system's capability.