Time-Domain Free-Field Measurements of the Relative Permittivity of Building Materials

• Published in: IEEE transactions on instrumentation and measurement Vol. 58; no. 7; pp. 2275 - 2282
• Main Authors: Grosvenor, C.A., Johnk, R.T., Baker-Jarvis, J., Janezic, M.D., Riddle, B.
• Format: Journal Article
• Language: English
• Published: New York IEEE 01.07.2009; The Institute of Electrical and Electronics Engineers, Inc. (IEEE)
• Subjects: Antenna measurements; Antennas; Building materials; Concrete; Construction materials; Deconvolution; Dielectric constant; Dielectric measurements; digital signal processing; Equations; fast Fourier transform (FFT); free-space measurements; inverse Fourier transform; Kirkwood-Fuoss equation; Mathematical analysis; Mathematical models; Optical reflection; Permittivity measurement; Plywood; Reflection; relative permittivity; Surface fitting; time domain; Time domain analysis; vector network analyzer (VNA); Walls
• ISSN: 0018-9456; 1557-9662
• DOI: 10.1109/TIM.2009.2013916

Time-domain free-field measurements comprised the dielectric properties of several common building materials using dual-ridged guide antennas and 1 mtimes1 m samples placed on an optical table covered with an absorber. The samples are polycarbonate, gypsum, plywood, a brick wall, and a concrete wall. Time gating and deconvolution are used to isolate a sample's front and back surfaces to obtain the measured reflection coefficients (RCs) and transmission coefficients. Theoretical reflection and transmission equations were generated from a plane-wave model. Relative permittivity is obtained by varying the parameters in the Kirkwood-Fuoss equation until a best fit between the theoretical and measured reflection and transmission coefficients is obtained.