Research on the propagation constant of the periodically slotted rectangular waveguide by equivalent circuit method

The influence of the structural parameters on the propagation constant of the leaky rectangular waveguide is studied by an equivalent circuit method and the dispersion equations are derived by the theory of transmission line. Using these equations, variation of propagation constant with the structural parameters is obtained and analyzed. And the propagation constants obtained from the equivalent circuit method were compared with those from the full‐wave simulation results. Both the results show that there is a critical length of the slots, below which the propagation constant of the leaky waveguide will be larger than that of the closed waveguide.