Detachable Ultrasonic Data Communication Through the Metal plate with NFC Technology

Data and energy transmission through the metal barriers enable us to monitor the environmental condition in the not accessible side of the metal chambers. In this study, near field communication (NFC) technology has been utilized for energy harvesting and data communication by replacement of RF antenna with ceramic PZTs. The main concept is based on energy and data transmission with ultrasonic wave by application of direct and indirect effect of piezoelectric. Due to the comb-resonance effect of metal barriers which has a dominant effect on the communication, a method is proposed to reduce the fluctuation and flatten the bandwidth in the designated frequency range (13.56 MHz). Additionally, detachable method of communication on the reader side by study on couplant material and a method for alignment of reader and transponder is discussed, in this paper. For the experimental investigation, 200 um-thick, 5mm-diameter disc PZTs have been utilized as the ultrasonic transducers of the communication system. Based on experimental results, 30mW energy could be harvested by means of NFC ICs to supply the sensor modules with integrated ADC which are used on the not accessible side of metal chamber.