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

An approach to obtain e ff ective control of insertion loss (IL) in wideband substrateintegrated waveguide (SIW) band-pass fi lter with several tapered Iris con fi gurations is presented in this paper. Several iris con fi gurations and iris parameters have been minutely studied and e ff ective postulates have been provided for accurate design of fi lters 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 modi fi ed into a band-pass fi lter with its pass band in Ku bands with minimal IL using waveguide iris method. The technique e ff ectively 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 fi nal con fi guration 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 fi lter design engineers considering all major parameters necessary foriI ndust rial/ scien ti fi c productions.