Numerical calculation of dipole antenna radiation pattern at interface between two media

The work examines the problem of numerical modeling of pulsed radiation from a dipole antenna lying at the interface between air and a dielectric medium. A brief description of the time domain finite difference modeling capabilities implemented in the gprMax software package is provided. In order to control the obtained numerical results, they are compared with known analytical solutions of two-dimensional radiation problems of an infinitely long line with a current, lying at the interface between two media; the radiation pattern is considered in both frequency and time domains. It is shown that the analytical and numerical solutions, when calculating the radiation pattern of pulsed radiation, give equivalent results. Disadvantages are noted of the numerical approach which copes well with calculations in the near field, while signal estimates in the far field can require excessive computational, including time, resources even for a relatively simple two-dimensional problem. The three-dimensional directivity patterns of pulsed radiation of a finite dipole antenna in the near field are also numerically calculated. The results obtained can be used in georadar practice in order to select a GPR survey scheme. The last section of the work is devoted to the examples of calculating signal attenuation with the radar range equation, taking into account numerically calculated radiation patterns.