Open-Wire Transmission Lines Applied to the Measurement of the Macroscopic Electrical Properties of a Forest Region
Abstract
The theoretical capabilities of two-conductor, open-wire transmission lines (OWLs) as probes to measure the macroscopic electrical properties of a forest are examined under the premise that a forest can be represented as a lossy dielectric slab. A laboratory experiment with a line inserted in a relatively homogeneous, isotropic slab of Styrofoam was performed to verify certain approximations in the analysis of such a line when a void (hole) exists in the slab near the line. The effective sensing radius for a 300-ohm line is shown to be about one and one-half line spacings. The limitations of a transmission-line probe for inhomogeneous and anisotropic dielectrics are discussed. The forest also is considered as a synthetic dielectric composed of lossy scatterers. The equivalent circuit of a short scatterer (length small relative to the RF wavelength) as a load on the transmission line is shown to be a lossy capacitor.
Document Details
- Document Type
- Technical Report
- Publication Date
- Oct 01, 1971
- Accession Number
- AD0755551
Entities
People
- Ching Chun Han
- Chung Lien Tien
- George Hagn
- John Taylor
Organizations
- SRI International