DUAL‐BAND BALANCED FILTERS IMPLEMENTED IN SUBSTRATE INTEGRATED WAVEGUIDE (SIW) TECHNOLOGY

This chapter introduces two types of balanced filters with dual operation bands utilizing the potential substrate integrated waveguide (SIW) technology. For the first type of dual‐band balanced bandpass filters (BPF), it is constructed by utilizing the TE
₁₀₁
and TE
₁₀₂
modes, where the common‐mode (CM) signals are effectively suppressed by the balanced sections resonating at the TE
₁₀₂
mode. As for the second type of dual‐band balanced BPF, it is designed by the adoption of TE
₁₀₁
, TE
₁₀₂
, TE201, and TE
₂₀₂
modes, where the CM signals are effectively suppressed by the balanced sections resonating at the TE
₁₀₂
and TE
₂₀₂
modes. The chapter shows a typical SIW cavity configuration. It deals with a new dual‐band balanced filter using high‐order resonant modes in SIW cavities. Specifically, in the differential‐mode (DM) response, the first passband is derived by the dominant modes, while the second passband is obtained by employing the higher‐order modes in the SIW cavities.