Modeling of Millimeter-Wave Propagation in Rain Based on Parabolic Equation Method

The parabolic equation (PE) method is proposed to model millimeter-wave propagation in rain medium. The rain medium is treated as an anisotropy mixture comprising of spherical and ellipsoidal raindrops with different sizes in atmosphere. Taking into account the effects of size, distribution, temperature, and shape of the raindrops on the dielectric property, we introduce an analytical formula for the effective permittivity of the rain medium. The PE model for estimating rain attenuation is developed via revising the refractive index by the effective permittivity. The values of specific rain attenuation predicted by the model agree well with those obtained by the ITU-R model, which verifies the accuracy of our method. Finally, the PE model is applied to simulate the propagation characteristics of millimeter wave in rain over irregular terrain.