Electrical optimization of power delivery through thick steel barriers using piezoelectric transducers

T. J. Lawry, K. R. Wilt, S. Roa-Prada, J. D. Ashdown, G. J. Saulnier, H. A. Scarton, P. K. Das, J. D. Pinezich

Research output: Book / Book Chapter / ReportResearch Bookspeer-review

34 Scopus citations


In many commercial, industrial, and military applications, supplying power to electronics through a thick metallic barrier without compromising its structural integrity would provide tremendous advantages over many existing barrier-penetrating techniques. The Faraday shielding presented by thick metallic barriers prevents the use of electromagnetic power-transmission techniques. This work describes the electrical optimization of continuouswave power delivery through thick steel barriers using ultrasound. Ultrasonic channels are formed by attaching pairs of coaxially-aligned piezoelectric transducers to opposite sides of thick steel blocks. The thickness of the steel considered is on the order of, or greater than, one quarter wavelength of the acoustic power signal inside of steel, requiring the use of wave propagation theory to properly analyze the system. A characterization and optimization methodology is presented which measures the linear two-port electrical scattering parameters of the transducersteel- transducer channel. Using these measurements, the simultaneous conjugate impedance-matching conditions at both transducers are calculated, and electrical matching-networks are designed to optimize the power transfer from a 50Ω power amplifier on one side of the steel block to a 50Ω load on the opposite side. In addition, the impacts of, and interactions between, transducer and steel geometries are discussed, and some general guidelines for selecting their relationships are presented. Measurements of optimized systems using transducers designed to resonate at 1 MHz with diameters from 12.7 mm to 66.7 mm, and steel block thicknesses from 9.5 mm to 63.5 mm, reveal power transfer efficiencies as high as 55%, and linear delivery of 81 watts through an optimized channel.

Original languageEnglish
Title of host publicationEnergy Harvesting and Storage
Subtitle of host publicationMaterials, Devices, and Applications
StatePublished - 2010
Externally publishedYes
EventEnergy Harvesting and Storage: Materials, Devices, and Applications - Orlando, FL, United States
Duration: 5 Apr 20106 Apr 2010

Publication series

NameProceedings of SPIE - The International Society for Optical Engineering
ISSN (Print)0277-786X


ConferenceEnergy Harvesting and Storage: Materials, Devices, and Applications
Country/TerritoryUnited States
CityOrlando, FL


  • acoustic-electric
  • continuous-wave
  • impedance matching
  • optimization of power efficiency
  • piezoelectric transducer
  • power harvesting
  • thick steel wall
  • ultrasonic


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