Compact Substrate Integrated Waveguide (SIW) Filter With Defected Ground Structure

A compact substrate integrated waveguide (SIW) filter with defected ground structure (DGS) is proposed. The DGS is etched on the ground plane of the SIW cavity, and it behaves as a resonator. Under such condition, better frequency selectivity contributed to three transmission zeros is obtained, and two of them are located at the lower stopband. The proposed filter, fabricated using standard printed circuit board technology, has the advantages of compactness, good spurious suppression characteristics and low cost. Its measured S-parameters agree well with the simulated ones.