Research On Characteristic Of Radio Wave Transmitting In Stratum Medium

An emergency security communication system is needed for the exploitation of mine and other underground buildings. In order to solve this problem, the best way should be penetration stratum communication, only by which can meet the needs of communication in the non-free space. Therefore, it is very essential to study the characteristic of the radio wave transmitting through the earth. The transmission characteristic of the radio wave in complex medium of the stratum is analyzed and researched in this subject, which provide the theoretic basis for design of the through-the-earth communication system for Mine. Then, the characteristic of the stratum and all kinds of parameters tied closely to transmission of the radio wave are analyzed, and the working frequency band is given as well. Based on the model of multi-layer stratum medium, which divided into two kinds of mutation and gradual change according to medium' permittivity, the mathematics expression of reflect and transmission coefficients of the radio wave's transmitting through the multi-layer stratum medium is deduced by way of analytic method respectively; and some useful data are worked out about the amplitude of wave which is transmitting in the stratum. Meanwhile, reflect and transmission coefficients of radio wave in the interface between the free space and the earth is worked out, together with the radio wave's transmission in the stratum is simulated used numerical method-FDTD(Finite Difference Time Domain).The conclusion obtained can provide theory basis for the design of the through-the-earth radio communication system. Besides, it can provide the experiences for other non-free spaces such as underground buildings and tunnel etc and it involves some theoretic value and practice significance. ...