Dual-Mode Substrate Integrated Waveguide Filter With Flexible Response

This paper proposes a novel dual-mode substrate integrated waveguide (SIW) filter technique. Based on the conventional dual-mode SIW structure, further investigation is performed. Multiple transmission zeros can be obtained at one side or both sides of the passband for an SIW cavity. Therefore, flexible design and high performance response can be available for dual-mode SIW filter. A dual-mode SIW bandpass filter with quasi-elliptic response and a dual-mode SIW diplexer with asymmetric channel response are simulated, fabricated, and measured to demonstrate and verify the novel property.