Measurement of Sea State by RF Interferometry

The mutual coherence function is derived for the scattered field due to a plane wave incident on the surface of the sea. The analysis is based on first order small perturbation theory, and neglects composite surface effects. The concept of an interferometer measuring the space correlation function of the scattered field providing information leading to the determination of the wave number spectrum of the sea surface is demonstrated. Assuming that the sea has a Phillips spectrum with a low cutoff number determined by the wind, a number of the basic physical properties of the proposed device are examined.