Transmitted fields of a directional antenna in proximity of a wall

Transmission of a directional antenna in near proximity of a building wall modelled by a semi-finite dielectric slab above a perfectly conducting ground is investigated and an accurate and fast method to predict wall penetration loss (PL) once the source/observation points are in proximity of the wall is proposed. First, the antenna is replaced by an array of electric Hertzian dipoles with approximately the same half power beamwidth. Second, the dipole array radiation is calculated both numerically and asymptotically. They are based on computation of Sommerfeld integrals using Filon quadrature (FQ) technique and the steepest descent method, respectively. Third, PL of a typical x-polarised and y-polarised horn and a z-polarised wire antenna, simulated in FEKO using the method of moments (MoM) is compared with that of, respectively, the x-, y- and z-directed dipole arrays calculated using FQ technique. A good agreement between MoM and the dipole model results are obtained for relatively short stand-off distances for which estimation based on slab transmission coefficient is not an accurate approximation. The proposed dipole array model with FQ technique makes calculation at least 7.5 times faster than FEKO. Fourth, PL for different wall permittivity and conductivity is studied.