Improved theory of propagation through slotted circular waveguide

The letter describes two types of correction to existing expressions for the radial-line susceptance arising from a uniform slot in the wall of a circular waveguide. These expressions lead to much more accurate values for the propagation coefficients of leaky-waveguide modes. For the H11 mode, favourable comparison is made between computed results and experimental results obtained previously by Harrington. Corrections to the susceptance expressions are presented for H0, E0, H1 and E1 radial-line modes, and, for the azimuthal-dependent modes, two slot positions are considered.