Electromagnetic Resonances of a Wire on an Earth-Air Interface
Abstract
A promising approach to detecting roadside bombs attached to command wires is the electromagnetic sensing and identification of the wires. The lowest five resonant frequencies of the wires, along with the widths of the resonances, can serve as a "fingerprint" for finding the wires. A first major step toward exploiting this fingerprint is to calculate the resonances and their widths for a straight wire on a flat interface between a homogeneous earth and air. The calculation of resonances requires extending the theory of the linear antenna to deal with a wire on the interface between two dielectric media, which we accomplish here. Complex-valued resonant frequencies are defined as those for which a certain homogeneous integral equation for the current in the wire on the interface has non-zero solutions. By applying a Galerkin procedure we obtain approximate numerical solutions for the resonant frequencies and their widths. A table of resonances is given for the case of a relative dielectric constant equal to 4 and for three values of the ration of the wire radius to wire length. MATLAB computer programs for determining resonant frequencies and widths for other parameter values are included.
Document Details
- Document Type
- Technical Report
- Publication Date
- Nov 12, 2009
- Accession Number
- ADA520611
Entities
People
- John M. Myers
- Sheldon S. Sandler
- Tai T. Wu
Organizations
- Harvard University