Study On The Antenna And Circuits Of Radio Frequency Identification (RFID) Tag Employing Metal Oxide TFTs Technology

Radio frequency identification(RFID)is an automatic recognition technology that identifies and tracks objects attached by tag through radio frequency signals.It can be used without direct contact with the object to collect and process the identity information carried by the object identified quickly,real-time and accurately,which increases the efficiency of information collection greatly.It has now been widely used in multiple areas,and has become the cornerstone of the internet of things.Metal oxide thin film transistor is a semiconductor with many advantages such as simple manufacturing process,high mobility and low cost.Fabricating RFID Tag employing MOTFT technology is expected to achieve high performance and reliable integrate flexible RFID tags that can be applied to areas such as wearable devices and bio-electronics,so it has high value to study.Based on the metal oxide TFT technology and ISO/IEC 14443 A standard,the antenna,digital logic circuit and analog front circuit of 13.56 MHz passive radio frequency identification tag are designed and fabricated,and the feasibility of RFID tag integrated preparation is explored.It mainly includes the following aspects: In the aspect of device,various MOTFT devices of different sizes are prepared,and the accurate device electrical parameters are extracted,and the SPICE simulation model of the device is fitted.In the aspect of antenna design,an on-chip inductance model based on MOTFT process is proposed.The influence of parasitic parameters on the performance of antenna and the challenge of design are analyzed.Under the premise of fully compatible MOTFT process,an on-chip antenna and its parallel resonance circuit with a quality factor of 16 are designed.Through the optimization of the layout design,the parasitic resistance of the on-chip antenna is reduced to the original half.In the aspect of digital logic circuit design,circuit modules such as clock generation circuit,ROM and its read circuit,Manchester coding circuit and subcarrier modulation are designed and prepared,and further integrated into the IC module capable of outputting an On-Off Keying(OOK)signal with the data rate of 23 KHz and subcarrier frequency of 190 KHz.In the aspect of analog front circuit design,a full-wave rectifier circuit based on NTFT cross-gate connections rectification and an Amplitude Shift Keying(ASK)modulation circuit based on resistance load modulation are designed and fabricated.The full-wave rectifier circuit can convert the frequency of 13.56 MHz and the amplitude of 5V alternating power supply into the 6V DC power supply,and the ripple factor control in about 10%.By designing and preparing the key module of RFID tag on the glass substrate,the feasibility of using MOTFT technology to fabricate RFID tags is preliminarily verified,and it has laid a solid theory and experimental basis for the further realization of practical MOTFT RFID tags and even flexible tags.