The study in fast calculation of Numerical Green Matrix of a surface antenna in a plane

In this paper, it is discovered that the correlation matrices of antennas whose scattering surface are within the same plane are diagonal matrices. By applying this conclusion to the Numerical Green Matrix Module in the NEC (Numerical Electromagnetic Code), the memory space used by simulation program is significantly reduced, and the computational speed is improved, when the initial structures are face structures within the same plane. In a simulated experiment of NASA ST5 antenna designing, the speed of computation with the method introduced in this paper is 25.3 times faster than that of original NEC, and uses as 1/858 memory as original NEC. Applying the approach to evolutionary antenna research can help with solving one of its great challenges: expensive and time-consuming computation.

I. Introduction

Antenna design problem is usually a kind of complex optimization problem. For example, the satellite antenna design problem of ST5(NASA ST5[1]) by NASA(National Aeronautics and Space Administration), set up an optimization model, which is according to the design requirement (as shown in Table.1), very complex, it's a nonlinear, multivariable, multiple-objective and constrained conditions optimization problem. To solve this kind of complex problems, the traditional algorithm is proved powerless. But the evolutionary algorithm which simulates the nature evolution process has potential advantages. In the mid 1990's, the evolutionary algorithm is applied to antenna design and optimization. For example, Haupt [3] designed an antenna array, Altshuler and Linden [4] designed a wire antenna, Jason etc. [5] designed an antenna and successes used in miniature satellites. In recent years, evolutionary antenna is still a hot topic in the antenna design research and the intelligent computing area [6–10].