Analysis of Radiation Characteristics of the Electric Dipole in the Rectangular Tunnel

The parameter of the rectangular tunnel have greatly influence on the radiation characteristics of a electric dipole. The expression of the electric and magnetic Hertz vectors in vertical direction was deduced by the method of the Fourier Transform. Based on the MATLAB software, the field strength against different environment was studied. The main conclusions are as follows: for the horizontal dipole, with bigger of the dielectric constant, the field strength is increase in low frequency, and is decrease in high frequency, if the frequency or the conductivity is greater, the field strength is rising, for the vertical dipole, if the frequency or the dielectric constant is bigger, the field strength is higher, and the field strength is smaller with higher of the conductivity. The attenuation rate of the field strength with the horizontal dipole is smaller than the vertical dipole. In the rectangular tunnel, the high frequency or the horizontal dipole is beneficial for the radio wave to propagate.