An Investigation of the Dipole Antenna Over Stationary and Time-Varying Irregular Surfaces.
Abstract
Investigations of electromagnetic scattering from rough surfaces have been oriented toward radar surveillance or remote sensing applications. An important problem that has been relatively unexplored is that of a dipole antenna close to and illuminating an ocean surface with spherical waves, for example, communication antennas on submarines or surface ships. The work is concerned primarily with the fluctuations in the far electric field intensity caused by reinforcement and cancellation of the direct wave by the wave reflected from a time-varying surface. The analysis starts with the simplest possible model of a time-varying surface. A vertical electric dipole is situated above a flat ground that varies sinusoidally about a fixed reference plane. Other simple models are considered, one of which shows that depolarization is introduced. The most sophisticated model of the ocean surface that is considered is one for a moving sinusoidal surface. Certain situations arise so that the sinusoidal model is a good approximation of an actual ocean surface. For the sinusoidal ocean surface model, the amplitude of the sine curve is small compared with a free-space wavelength; therefore, a Fourier integral-perturbation series approach can be used to solve the boundary value problem. (Author)
Document Details
- Document Type
- Technical Report
- Publication Date
- Jun 10, 1971
- Accession Number
- AD0728033
Entities
People
- Dennis E. Fessenden
Organizations
- Naval Undersea Warfare Center