Research On The Key Technology Of Through–metal-wall Wireless Power And Data Transmission System Based On The Ultrasonic Transducers

In military equipment and civil industry,through-metal-wall wireless data communication is becoming a research focus.The electromagnetic wave signal is difficult to pass through the thick metal wall due to the shielding effect of the metal barrier.Ultrasonic waves have the advantages of good penetration and high transfer efficiency,which make it possible to power and communicate with the electronics enclosed in hermitical metal structure for condition monitoring while maintaining the integration of the structure.In this paper,the domestic and foreign state-of-art is investigated.The key technologies of ultrasonic wireless energy and data transmission system are studied.The experimental device of through-metal-wall ultrasonic energy transmission and data communication system is developed,and the device is tested,achieving power delivery and data transmission through metal barrier based on ultrasonic.The main contents of the paper include:(1)The sound field model of through-metal-wall ultrasonic transmission is established.The characteristics of the ultrasonic channel are analyzed.The PSpice circuit model for through-metal-wall ultrasonic data communication is built up based on the equivalent circuit theory.The communication mode based on impedance modulation is simulated and the feasibility of the data transmission is verified theoretically.(2)The overall structure and hardware circuits of the through-metal-wall wireless power and data transmission system are designed.The circuits are divided into two parts,the internal and external circuits of the metal structure,which include the internal energy collection circuit,digital signal modulation circuit,temperature sensor signal acquisition,power amplifying and demodulation circuit.(3)The software of through-metal-wall ultrasonic wireless data transmission is designed and developed,which fulfills the functions of the internal temperature data acquisition,impedance modulation control based on the MSP430 microcontroller,the external transmission data decode,communication with PC based on MSP430 microcontroller,and data display interface based on PC.(4)The circuits and software of the system are debugged and tested.The performance of the system for energy and data transmission is experimentally studied.The results show that the system has the capability of wireless transmission of 45 mW power and achieving a transmission data rate up to 4.8Kbps through a 20 mm thick metal wall using ultrasonic waves.