Skip to Main Content
U.S. Forest Service
Caring for the land and serving people

United States Department of Agriculture

Home > Search > Publication Information

  1. Share via EmailShare on FacebookShare on LinkedInShare on Twitter
    Dislike this pubLike this pub
    Author(s): W. L. James; Y.-H. Yen; R. J. King
    Date: 1985
    Source: (Research note FPL ; 0250):9 p. ; 28 cm.
    Publication Series: Research Note (RN)
    Station: Forest Products Laboratory
    PDF: View PDF  (125 KB)


    The attenuation, phase shift and depolarization of a polarized 4.81-gigahertz wave as it is transmitted through a wood specimen can provide estimates of the moisture content (MC), density, and grain angle of the specimen. Calibrations are empirical, and computations are complicated, with considerable interaction between parameters. Measured dielectric parameters, however, correlate uniquely and repeatably with MC over a range of MC at least as great as 100 percent of the dry weight of the wood. Grain angle can be deduced reliably when the specimen thickness and MC are great enough to introduce sufficient dielectric anisotropy to appreciably depolarize the incident wave. At present, the apparatus and techniques are very complex, but the principles developed by this research show the method to be feasible for nondestructive testing of lumber as it is produced.

    Publication Notes

    • We recommend that you also print this page and attach it to the printout of the article, to retain the full citation information.
    • This article was written and prepared by U.S. Government employees on official time, and is therefore in the public domain.


    James, W. L.; Yen, Y.-H.; King, R. J. 1985. A microwave method for measuring moisture content, density, and grain angle of wood. (Research note FPL ; 0250):9 p. ; 28 cm.


    Google Scholar


    Microwaves, Dielectric properties, Non-destructive testing, Moisture content, Density, Attenuation, Grain and figure, Wood density, Wood moisture, Phase shift, Depolarization, Homodyne

    Related Search

    XML: View XML
Show More
Show Fewer
Jump to Top of Page