Novel substrate integrated waveguide cavity filter with defected ground structure

An open-structure eigenvalue problem of substrate integrated waveguide (SIW) cavity structures is investigated in detail by using a finite-difference frequency-domain method, and the quality (Q) factor of such SIW cavities is given. Based on the concept of a defected ground structure, a new class of SIW cavity bandpass filters are designed, fabricated, and measured around 5.8 GHz. With their fabrication on standard printed circuit boards, such filters present the advantages of high-Q factor, high power capacity, and small size. Simulated and measured results are presented and discussed to show promising performances of the proposed filters.