Compact Band-Stop Filters Based on Single Ridge Waveguide Lines, Resonators, and Coupling Elements

This paper presents a methodology to design compact band-stop filters based on ridge waveguide lines and resonators. Such filters find application in high-power systems where isolation between high-power transmitters is needed. The presented design utilized transversal ridges to act as a coupling mechanism between ridge waveguide resonant cavities and ridge waveguide lines. This enables the designer to prevent unwanted coupling between the cavities and allows them to be spaced at λg/4 rather than 3λg/4, which is almost a must in waveguide realizations. Through the use of this design methodology, compact BSFs with moderate power handling and losses can be realized. A design example of a fifth order wide-band BSF covering both X- and Ku-bands is discussed in detail followed by an experimental prototype which was fabricated and tested demonstrating good results without any tuning.