Propagation and suppression method of lightning wave in coaxial line

Abstract

In accordance with the theory of waveguide, the electric field and magnetic field equations of transverse electromag- netic propagating in coaxial line were derived. Based on the equivalent impedance of coaxial line after the broken-down of gas discharge tube (GDT) that connected in parallel, the corresponding relation between reflection coefficient and the equivalent impedance of the main modules at the reflector surface of Z = 0 is established. The high-order mode function of the excitation magnetic current was also analyzed. To solve the transmission and suppression problems of lightning wave propagation, we combined theories with experiment and draw conclusions: a) higher mode will be excited when the lightning wave propagates on the coaxial line with the line terminal to be open; b) the lightning wave energy will be absorbed by terminal load and higher mode will be also excited when the characteristic impedance of the load is same with the coaxial line; c) the GDT will become a reflector when the lightning wave go through it and part of the wave will be reflected. Part of the energy of the lightning wave will be discharged by GDT and only a little of the energy will be absorbed by the load. The experimental results are consisted with the theories analysis and have a great of significance in practical applications.