Low Power Backscatter Signal Transmitter Based On Tunnel Diode

With the rapid development of the Internet of Things technology,sensor networks,drones and satellites have been widely used in many industries such as healthcare,smart cities and precision agriculture.As a key application in the Internet of Things,RFID(radio frequency identification)has gradually begun to develop in all walks of life,but its power consumption problem has also become increasingly serious.The core technology of RFID-backscattering technology,because of its low power consumption and support for low-rate communication,has become a key point in solving the power consumption problem of radio frequency identification.Therefore,researchers in the low-power IoT industry have begun to study backscattering.technology.Due to the backscatter signal path loss and power limitation,the existing backscatter technology can only achieve short-range communication,and it cannot compete with wireless communication technologies such as Wi-Fi that can cover widely.This thesis focuses on a new type of low-power backscatter communication technology.By comparing the existing implementation schemes of several backscatter signal amplifier prototypes,a new type of low-power backscatter based on tunnel diodes is proposed.Compared with the existing radio frequency tags,the scattered signal transmitter has the characteristics of low power consumption,high signal gain,and long communication distance.The main work of this thesis is as follows:First,this thesis investigates and compares the current research status at home and abroad,analyzes several new backscattering technologies,and summarizes the current development direction and trend of backscattering technologies.Secondly,the basic theory of backscattering technology is researched,several existing backscattering technologies are introduced,and some dual-port devices that can be used to achieve amplification are analyzed.The main work of this thesis is to analyze the performance of the tunnel diode-based reflective amplifier,study the amplification and modulation of the backscatter link,and select the AI301A tunnel diode as the core to independently design a new type of low power backscatter.Signal transmitter.The circuit mainly includes an antenna,an impedance matching module,a reflection amplifier module,a DC bias module,and a modulation module.According to the design scheme,the physical production and detailed test of the tunnel diode-based signal transmitter are performed.Through the system test,in the UHF frequency band,the prototype of the signal transmitter can generate a return gain of up to 40dB under an incident signal as low as-50dBm,and the bias power is less than 250?W,and the performance is better than similar research results.On the other hand,the designed impedance matching network circuit can also adjust the center frequency well.The center frequency adjustment function can be completed by manually adjusting the knob of the variable capacitor,which has a high adjustment accuracy,a wide range and can be operated repeatedly,which is the first of its kind in known research work.Compared with the commonly used electronic tags in the market,the power of the backscattered signal of the backscattered signal transmitter is significantly enhanced,and the difference of the backscattered power can be up to 21.45dB.The modulation circuit modulates the backscattered signal through a DC bias,and the prototype can complete normal frame transmission.The test results show that the design,fabrication and debugging of the low power backscatter signal transmitter based on the tunnel diode have been well completed in this thesis.Finally,the thesis summarizes the work content and points out that the work content needs to be improved in the future.