Document Type : Research Article

Authors

1 Assistant Professor. Department of Electrical Engineering, Technical and Vocational University (TVU), Tehran, Iran.

2 Assistant Professor. Aerospace Research Institute, Ministry of Science, Research and Technology, Tehran, Iran.

Abstract

This research is focused on the design of microwave filters with asymmetric frequency response with a single transmission zero below or above the passband. The procedure to design such filters in dual-mode cylindrical cavities is presented. It is shown that while realizing filters, especially with a transmission zero below the passband is quite challenging, high-performance filters with transmission zeros either below or above the passband can be easily implemented in dual-mode cylindrical cavity filters. Furthermore, it has been demonstrated that changing the position of the transmission zero from below to above the passband may be conducted with minimum changes in the configuration and physical dimensions of the filter, thus can be performed only by rotating the irises and cavities and using tuning screws, thus bypassing the need for re-manufacturing the filter. To demonstrate the design procedure, two filters are designed and simulated using full-wave electromagnetic software. The simulation results very well match the prescribed specifications of the filters.

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