Study On The Design Of RFID Tag Modules Based On Metal Oxide TFTs

The newly developed metal oxide(MO)TFTs have advantages of high mobility,low sub-threshold voltage and high current on/off ratio compared to amorphous silicon TFTs.MO TFT have advantages of simple process compared to low temperature poly-silicon TFTs.MO TFT have advantages of good transparence,compatibility with flexible substrate compared to conventional CMOS technology.TFTs have been wildly applied in the panel display area and the sensor area.TFTs have a bright future in the Internet of Things and wearable devices.As a underlying perception technique of the Internet of Things,Radio frequency identification(RFID)is one of the most important technology in the automatic identification area.The main work of this paper:For the front end of the RFID tag,we fabricate rectifier circuits and give the measurement results.In addition,we propose an high-gain amplifier combining the load impedance enhancement and equivalent transconductance enhancement technique.The amplifier shows the open loop differential mode gain of 30dB,-3dB bandwidth of 6 kHz,unity gain bandwidth of 103kHz and phase margin of 36 degree.We use the bootstrapped structure gate to design ring oscillator,5-bit counter,2-to-4decoder,read-only-memory and Manchester encoder.And utilize these modules to bulid a Manchester Encoded Data Transmission Circuit.The modules are only realized by two king of gates:NOT gate and NOR gate.The number of the total transistor of the circuit is 300.The total area of the circuit is 6.5mm~2.The measured result shows that the Manchester Encoded Data Transmission Circuit read out the ROM data successfully.Under the VDD=5V,the data rate reaches 103kbps,the power consumption is 3.8m W.We use the dynamic-load Pseudo-CMOS gate to design the low power digital modules,including D-flip-flop,2-to-4 decoder,XOR gate and ring oscillator.The dynamic-load method didn't need external control signal and extra transistors.It has the advantages of simple and tending to realize.Compared to the traditional D-flip-flop,2-to-4 decoder,XOR gate and ring oscillator,respectively,the measured results shows that the power consumption of the proposed D-flip-flop is reduced by 12.8%.The simulated result shows that the proposed2-to-4 decoder and XOR gate is reduced by 35%and 22.6%,respectively.For the measured result of the proposed 11-stages ring oscillator,it is measured that the power-delay-product of the proposed ring oscillator is reduced by more than 50%under the same value of supply voltage.At the same oscillation frequency,the power consumption tends to be reduced by18%as oscillation frequency increases.Furthermore,the peak-to-peak voltage of the proposed RO can almost receive a full swing at any supply voltage.This paper focus on the realization of the modules of the RFID tag.We fabricate the amplifier,the Manchester Encoded Data Transmission Circuit,the dynamic-load low power D-flip-flop and the low power 11-stages ring oscillator.The experiment provides new oration for the wildly application of TFTs.