Complex Permittivity Estimation for Construction Materials based on PSO Method

To determine propagation characteristics in buildings for fifth-generation (5G) wireless communication, it is necessary to obtain the complex permittivity of the construction materials at millimeter-wave band. Backward reconstruction of complex permittivity of construction materials in free space at millimeter-waves remains a challenging and up to date complex problem. A procedure for the estimation of the complex permittivity of construction materials based on Particle Swarm Optimization (PSO) method is presented in this paper. The complex permittivity is extracted from the transmission and reflection coefficients for perpendicular polarization over 40-50 GHz, and verified by reflection coefficients for parallel polarization. This method is relatively precise and fast which gives a good estimation of complex permittivity.