Analysis of radiation loss in post-wall waveguides

The post-wall waveguide consists of two rows of metal posts sandwiched between two parallel metal plates. The post-wall waveguide is suffering from the radiation through the gaps between posts. In this paper, a finite section of post-wall waveguide is considered. A horn consisting of metal posts is attached to one end of waveguide, while the other end is terminated with metal posts. A plane wave is incident at the horn so that standing waves are excited in the waveguide. The standing wave pattern is computed by using the method of moments (MoM) with global base. The attenuation constant and the wavelength of the guided mode are obtained by curve fitting of the standing wave pattern.