Category - Validation

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 […]

Discover the perfect balance: a simple dual-band vertical dipole, AN-SOF modeling, and real-world results. Elevate your ham radio experience.

Discover the vital role of historical theoretical results alongside advanced numerical calculations in accurately approximating current distribution on linear antennas.

This article validates the results obtained from AN-SOF by replicating a panel antenna model with nine dipole radiators. The model used for validation was published by the IEC and an excerpt of the document can be accessed by following this link...

The V antenna is a traveling wave antenna where high directivity can be achieved when the length of each arm of the V is greater than the wavelength. However, the angle between the arms must be chosen so that the fields radiated by both arms constructively add in the forward direction. Several authors have investigated […]

With the utilization of enhanced techniques for impedance calculation of monopoles above radial wire ground screens, our study paves the way for improved performance in LF/MF antenna design.

In absence of power losses, the power radiated by any antenna must be equal to its input power. In other words, the radiation resistance of a lossless antenna must match its input resistance. When comparing these two resistances we have another validation check of a numerical method. Fig. 1 shows the input resistance of a […]

One of the validation checks consists of incrementing the number of segments as the antenna length, radius and source gap remain constant. In this way, the input impedance should converge to an asymptotic value as the number of segments increases. Fig. 1 shows the input impedance of a center-fed dipole antenna as a function of […]

Since there is a lot of theoretical data available for the input impedance of a linear antenna, we will compare the simulation results with those obtained theoretically. Among the theoretical results, we have chosen the King-Middleton’s because from our point of view it is the most elaborate analytical solution. It is based on an expansion […]

This article is based on the geometric parameters for the helix defined in this link >. A helical antenna operating in axial mode can be a highly directional radiator. Its radiation pattern consists of a main lobe and several secondary lobes, as Fig. 1 shows. The gain increases as the number of turns increases for […]

Helical Geometry The current distribution in a helical antenna of arbitrary size cannot be described in terms of simple series or elementary functions, so most of the available data has been obtained experimentally. The helical antenna was invented by Prof. John Krauss who has investigated its performance as a function of geometry extensively. Refer to “Antennas” […]

Assuming a uniform current distribution along a small circular loop > has allowed us to obtain closed-form expressions for the radiation resistance and directivity. When the loop circumference is comparable to the wavelength, the current distribution cannot longer be assumed uniform but a Fourier series is applied to approximate it. Also, a delta gap voltage […]

Among the advantages of the Conformal Method of Moments (CMoM) > implemented in AN-SOF is the ability to model exactly the contour of curved antennas. Besides, calculations at extremely low frequencies are possible or, equivalently, when the antenna size is a tiny fraction of a wavelength. Both advantages will be demonstrated in this article for […]