Dual-Band Balanced to Unbalanced Multilayer Filtering Magic-T Based on SIW Cavity

摘要

A new dual-band balanced to unbalanced (BTU) multilayer filtering magic-T (FMT) based on square substrate integrated waveguide (SIW) cavity is proposed in this letter. Degenerate TE ??? and TE ??? modes are exploited to realize the requested dual-band filtering responses and in-/out-of-phase characteristic. The requested differential-mode (DM) transmission, common-mode (CM) suppression, and port-to-port isolation can be obtained by appropriately placing the input-output ports and coupling slots. Multiple transmission zeros (TZs) are introduced to improve frequency selectivity, and the center frequencies (CFs) can be flexibly controlled to some extent. For validation, a prototype dual-band BTU FMT operating at 11.6 and 19.1 GHz is fabricated and measured. It can be obtained that the simulated results are in good agreement with the measured ones.

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