Modeling and Evaluation of Piezoelectric Transducer (PZT)-Based Through-Metal Energy and Data Transfer

Through-metal transfer of energy and data using piezoelectric transduce can avoid the potential leakage problem caused by physical penetrations and wired feed-through. The through-metal transfer efficiency of energy or data is determined by the relative pressure on the receiving PZT (piezoelectric transducer). Hence, in this paper, we first propose the Spatial Equivalent Plane Acoustic Pressure (SEPAP), which is defined as the integration of the acoustic pressure over the receiving area, to model the pressure on the receiving PZT. Then we analyze the features of SEPAP and the factors impacting it by utilizing COMSOL. Furthermore, we propose a low-cost and small-size prototype for simultaneous transfer of energy and bidirectional communication through metal by using two pairs of PZTs working on different resonant frequencies. Extensive experiment has been done on evaluating the match between SEPAP transfer efficiency and the power transfer efficiency and analyzing the achievable data rate for bi-directional communication. Test through a 20 mm aluminum alloy plate shows that power transmission with efficiency 20.3% and data communication rate up to 38.4 Kbps can be achieved simultaneously.