Analysis of the axial dipole antenna propagation characteristics in rectangular tunnel

Using dyadic green´s function and the antenna surface boundary conditions, the integral equation of the antenna in a rectangular coal mine tunnel is established. The radiation modes of the line antenna are analyzed, and the unitary transmission powers distributing of electromagnetic wave transmission mode and the maximum transmission power mode are given. The results show that the electromagnetic wave is TM mode and propagates in multimode while the antenna is located along axial in rectangular tunnel. When the antenna moves along horizontal or frequency is changed, main transmission power modes are distributed in an arc, and the maximum power model index changes a little.