Control of Insertion Loss in Substrate-Integrated Waveguide Band-Pass Filter Using New Tapered Waveguide Iris Technique

An approach to obtain effective control of insertion loss (IL) in wideband substrateintegrated waveguide (SIW) band-pass filter with several tapered Iris configurations is presented in this paper. Several iris configurations and iris parameters have been minutely studied and effective postulates have been provided for accurate design of filters with low IL throughout the transmission bandwidth. Basic structure is designed over a substrate with dielectric constant 3.2 and material thickness of 30 mils. The structures are then successfully modified into a band-pass filter with its pass band in Ku bands with minimal IL using waveguide iris method. The technique effectively serves the purpose to achieve greater control over the IL and isolation. Maximum IL of 2 dB is reduced by 1.5 dB and close to 0.5 dB IL is obtained in the final configuration using the tapering technique. Proposed techniques are supported with theoretical explanations. All designs are fabricated, and measured results are found to validate the concept produced in this paper. The study provides a direct solution to the SIW Iris filter design engineers considering all major parameters necessary foriIndustrial/scientific productions.