The Research For Numerical Stimulation Of Path Loss In The Band Of 30-88MHz

Nowadays the research of the performance of radio path is on the first place in radio communication which is important in every aspect of the life. And as we know, the environment of radio path should be stimulated and analyzed based on actual and concrete surrounding in according to different transfering paths and diverse geographic characters.The wireless communication in the frequency band of 30~88MHz is always employed among moving cars, whether as transmitting or receiving terminals, of course, between which the path is complicated and complex.Therefore to provide a well communication system between moving bodies, the propagation characteristics of wireless communication in the frequency band of 30~88MHz should be deeply studied.This paper supplements and amends Okumura-Hata formula in the frequency band of 30~88MHz in some extent based on practical environments'electromagnetical simulation results, with which computational results from Okumura-Hata formula are compared, using the function of Dynamic Link from 3D electromagnetical simulation software of Ansoft HFSS, which makes electromagnetical simulation computation for comparatively large and complicated practical environments possible, taking the Finite Elememt Method(FEM) as its primary theory and physical prototype as its foundation, and then makes the formula better used and expands its serviceable range to the lower frequency range to enlarge its application and practicability.This paper mainly presents as following,Firstly, it is about researching background and current situation of the mobile communication,and then simply summery of this paper.Secondly, it introduces the formula of Okumura-Hata, which is helpful to let the content go forward.The third, it summarizes the fundamental knowledge and computing theory of Ansoft HFSS, the first electromagnetic stimulation software of three dimensions ,and used a lot in this paper.and its advanced key technique of Dynamic Link.The fourth, it provides modified Okumura-Hata after a large amount of numerical stimulation experimental, and two typical examples based the modified formula, which expands the modified formula'using range and enlarges its practicability.The last,it sums all the work up in this paper, and does some outlook.