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A useful method for monostatic RCS reduction of unavoidable shapes in desired frequency bandwidth and angle range is proposed. The proposed method is based on the concept of the random scatterer for RCS reduction and the genetic algorithm for optimization. PO, MEC, and SBR methods are used to obtain RCS. Target shapes whose RCS we want to reduce are basically a plate and finally a scale model tank. Results show that monostatic RCS of a fixed shape can be reduced by the proposed method. [ABSTRACT FROM AUTHOR]

New expressions for the narrow aperture dimension of the pyramidal horn are presented. They are obtained by using a differential evolution algorithm (DEA), and are used in successfully designing optimum gain pyramidal horns. The DEA is a simple, fast, and robust evolutionary algorithm for solving general type of numeric optimization problems. Design parameters of the horn are determined from the simple and explicit analytical formulas. These formulas do not need the application of the iterative methods, and are not restricted to the high-gain horn designs. The gain of a pyramidal horn is computed without approximating the path length error. Better accuracy with respect to the previous design methods is obtained for various pyramidal horn design examples. [ABSTRACT FROM AUTHOR]

In this paper, the performances of a general MIMO system with arrays at both ends adopting different antenna polarization combinations are studied. Our results show that MIMO systems exploiting the vertically co-polarized antenna arrays at both ends outperform, the horizontally co-polarized combination. The adoption of the orthogonal polarization antenna arrays at both ends can achieve parallel transmission and reception pairs at the expense of some subchannel gains, and thus is an efficient way for enhancing channel capacity in a poor-scattering environment. When cross-polarized antenna combination is used at both ends, both isolation and correlation properties are needed to fully describe the system performance whereas a co-polarized antenna combination scheme can be described by correlation property alone. [ABSTRACT FROM AUTHOR]

The boundary value solution of electromagnetic radiation from an axis-asymmetric slot antenna on a perfectly conducting prolate spheroid coated with a confocal sheath is presented. The electromagnetic fields are expanded in terms of prolate spheroidal vector wave functions. The unknown expansion coefficients are determined from a set of linear equations derived from the application of boundary conditions on the tangential fields' components. Numerical results for radiation patterns and power are presented. It is found that the thickness of the sheath has a significant effect on the radiated fields, and the radiated power is greatly enhanced for certain values of the sheath thickness. [ABSTRACT FROM AUTHOR]