Category - Background Theory

The AN-SOF engine is written in the C++ programming language using double-precision arithmetic and has been developed to improve the accuracy in the modeling of wire antennas and metallic structures in general. The computer code is based on an Electric Field Integral Equation (EFIE) expressed in the frequency domain. The current distribution on wire structures is computed by […]

The current distribution on metallic surfaces with ideal conductivity can be found by solving an Electric Field Integral Equation (EFIE) expressed in the frequency domain: where: Ei: Incident Electric Field on the surface S. n: unit vector at point r on the surface S. k: wave number. J: unknown electric current density flowing on the […]

The kernel is the core of the integral equation that is solved in AN-SOF by means of the Method of Moments to obtain the current distribution on metallic wires. Since the kernel cannot be calculated analytically in closed form, several approximations exist.

The Method of Moments (MoM) is a technique used to convert the EFIE into a system of linear equations that then can be solved by standard methods. For simplicity, the integral (linear) operator in the Electric Field Integral Equation > (EFIE) will be denoted by L. Then, the EFIE takes the form: where ET is the […]

If a discrete voltage source is placed at the i-th segment, the corresponding element in the voltage matrix is simply equal to the voltage of the generator. Thus, When an incident plane wave is used as the excitation, each wire segment is excited by the incoming field, which has the form: where k is defined by […]

Many examples show the advantages of using curved segments with respect to the stability and convergence properties of the solutions. Due to the improved convergence rate, accurate results can be obtained with reduced simulation time and memory space. Fig. 1 shows the dimensions of a center-fed helical antenna in free space (normal mode). Figs. 2 and 3 show […]