EM parameters of regular polygonal waveguide

The paper presents theoretical analysis of regular polygonal waveguide (RPW). It is shown that there is an analogy between the characteristics of RPW and cylindrical waveguide (CW). Dimensions of an equivalent CW can be analytically determined from the dimensions and the number of sides of the PRW. This enables deriving analytical expressions for parameters of a given RPW, such as propagation constant, cut- off frequency, guided wavelength, and attenuation below cut-off frequency. The derived formulae have been verified by accurate HFSS 3D electromagnetic simulations of pentagonal (n = 5), hexagonal (n = 6) and heptagonal (n = 7) RPWs, showing excellent agreement between the theoretical predictions and the simulations.