Rectangular Waveguide Filters With Meandered Topology

• Published in: IEEE transactions on microwave theory and techniques Vol. 66; no. 8; pp. 3632 - 3643
• Main Authors: Teberio, Fernando, Percaz, Jon M., Arregui, Ivan, Martin-Iglesias, Petronilo, Lopetegi, Txema, Laso, Miguel A. G., Arnedo, Israel
• Format: Journal Article
• Language: English
• Published: New York IEEE 01-08-2018; The Institute of Electrical and Electronics Engineers, Inc. (IEEE)
• Subjects: Band-pass filters; Bandpass filter; Bandpass filters; Bends; Electromagnetic wave filters; Fabrication; impedance matching; Insertion loss; Low pass filters; low-pass filter; Mathematical analysis; Prototypes; Rectangular waveguides; Reflectance; Robust design; Routing; stepped impedance; Topology; waveguide filter; Waveguide filters
• ISSN: 0018-9480; 1557-9670
• DOI: 10.1109/TMTT.2018.2845872

In this paper, a new topology for rectangular waveguide bandpass and low-pass filters is presented. A simple, accurate, and robust design technique for these novel meandered waveguide filters is provided. The proposed filters employ a concatenation of ±90° <inline-formula> <tex-math notation="LaTeX">E </tex-math></inline-formula>-plane mitered bends (±90° EMBs) with different heights and lengths, whose dimensions are consecutively and independently calculated. Each ±90° EMB satisfies a local target reflection coefficient along the device so that they can be calculated separately. The novel structures allow drastically reduce the total length of the filters and embed bends if desired, or even to provide routing capabilities. Furthermore, the new meandered topology allows the introduction of transmission zeros above the passband of the low-pass filter, which can be controlled by the free parameters of the ±90° EMBs. A bandpass and a low-pass filter with meandered topology have been designed following the proposed novel technique. Measurements of the manufactured prototypes are also included to validate the novel topology and design technique, achieving excellent agreement with the simulation results.