Capacitive Obstacle Realizing Multiple Transmission Zeros for In-Line Rectangular Waveguide Filters

(c) 2016 IEEE. Personal use of this material is permitted. Permission from IEEE must be obtained for all other users, including reprinting/ republishing this material for advertising or promotional purposes, creating new collective works for resale or redistribution to servers or lists, or reuse of any copyrighted components of this work in other worksThis paper presents a capacitive obstacle for rectangular waveguide filters capable of realizing multiple transmission zeros (TZs). By combining a capacitive window with multiple thin stubs, a filter designer has the ability to control the total coupling implemented by the obstacle, and the frequency location of the TZs generated. The resulting structure is compact, and can be employed at the input/output and intermediate stages of direct-coupled-resonator filters. This letter includes a parametric analysis of the obstacle and practical design guidelines. To validate its practical application, an in-line five-pole filter realizing three TZs has been successfully realized.This work was supported by the Spanish Ministerio de Economia y Competitividad under R&D project TEC2013-47037-C5-1-R.Carceller Candau, C.; Soto Pacheco, P.; Boria Esbert, VE.; Guglielmi, M. (2016). Capacitive Obstacle Realizing Multiple Transmission Zeros for In-Line Rectangular Waveguide Filters. IEEE Microwave and Wireless Components Letters. 26(10):795-797. doi:10.1109/LMWC.2016.2605462S795797261