Analysis and Application of Triple-Post Discontinuity in Circular Waveguide

This article presents the analysis of scattering characteristics of three symmetrical radially directed thin posts in an oversized circular waveguide in the transverse plane using the method of moments. Simulated data on return loss of the dominant mode and higher-order mode TE 21 have been compared with the data computed using Ansys high frequency structure simulator (HFSS; Canonsburg, PA, USA). The data on return loss for the incident TE 11 mode have been compared with experimental data for an oversized cylindrical waveguide loaded with the three posts. Also, the above analysis has been applied for designing a conjugate matched feed horn, which is used to cancel the cross-polar components generated in an offset reflector antenna. The primary pattern of the conjugate feed horn has been simulated and optimized using Ansys HFSS. The secondary pattern has been calculated using a general reflector antenna software package (GRASP; TICRA Engineering Consultants, Denmark).