Abstract
In many electromagnetic engineering applications, the use of modeling of electromagnetic scattering and radiation has become more widespread. There is a growing number of techniques that are being developed that help obtain more accurate results while being less computationally demanding. A well-known method for calculating the scattered electromagnetic field from an object is the Method of Moments (MoM) which is the solving of an integral equation over a finite, discretized space where the known boundary conditions are projected onto a set of weighting functions. The MoM can be used on any shape making this method very versatile for regular and irregular objects. Other methods have been created that generate accurate results while being computationally faster than previous models, however, there has not been a lot of improvements on understanding the physics of the scattering process. Recently the Remote Sensing Group at the University of Massachusetts Dartmouth has developed a new method for modeling electromagnetic scattering. With the use of the Addition Theorem for Bessel and Hankel functions the scattering matrix is broken down into the spectral signatures of the sources projected onto the spectral signatures of the observation points. Doing this enables the separation of the source and observation points allowing the spectral signature of the currents to be defined as an image current cloud that is located inside the scattering object. This method, known as the Spectral Projection Model, was tested for accuracy when calculating the scattered fields as well as the time it took to calculate these fields compared to the MoM approach. From there multiple calculations were made with variations in the axial ratio and size of the cross-section to find a relationship between the angular coherence of the received field and the shape and size of the scattering object with a variation in the angle of incidence. The angular coherence of the scattered signal determines the resolution of radar imaging process. Radar imaging systems utilize geometric diversity obtained from measurements from a wide variety of different viewing angles to generate high resolution images of the scene. In this study, the impact of shape and size on the angular coherence is investigated by simulating radar scattering from a variety of different elliptically shaped cylinders. The variation in the bistatic angle was also considered in the angular coherence results.