# Accession Number:

## ADA503267

# Title:

## Analysis of Curved Frequency Selective Surfaces

# Descriptive Note:

## Final rept. 5 Apr 2007-2008

# Corporate Author:

## ZAGREB UNIV (CROATIA)

# Personal Author(s):

# Report Date:

## 2008-05-16

# Pagination or Media Count:

## 76.0

# Abstract:

This report results from a contract tasking University of Zagreb as follows 1. Formulation of the problem. First period of the project is reserved for making a detailed formulation of the problem. Our starting point will be the existing MoM based program for analyzing patch arrays on placed on cylindrical and spherical structures programs CyMPA and SMiPA that are developed under the projects F61775-99-WE040 and F61775-01-WE024. The main difference between radiation and scattering problems is in the excitation model. We will assume two types of excitations a plane wave impinging on a curved periodic structure needed for calculating RCS of the curved FSS, and the far field radiation pattern of an antenna inside the radome needed for calculating the radiation pattern of the antenna with radome the radome is usually in the far-field region. Both the plane wave and the field radiated by the primary antenna will be expanded into a series of cylindrical or spherical harmonics. Another large difference is in the size of the considered structure the radome is usually very large in terms of the wavelength. 2. Modeling the RCSradiation pattern with approximate way of calculating mutual coupling between patchesapertures. The process of determining the scattered field from the FSS radome can be divided into two steps. In the first step the real or equivalent currents on patches or slots will be determined, while the electromagnetic field radiated by this currents will be computed in the second step. The array size will be the reason why the mutual coupling effects will be calculated in an approximate way each patch or slot will be considered in an equivalent infinite planar or cylindrical environment. By this we will be able to analyze conformal arrays of patches and apertures of different size. 3. Modeling the RCSradiation pattern with rigorous way of calculating mutual coupling between patchesapertures. 4. Development of experimental model.

# Descriptors:

# Subject Categories:

- Theoretical Mathematics
- Atomic and Molecular Physics and Spectroscopy