Compact Wideband-Folded Ridge Substrate-Integrated Waveguide Filter

In this letter, a novel folded ridge substrate-integrated waveguide (FRSIW) is proposed by folding a classic ridge substrate-integrated waveguide (RSIW). The FRSIW demonstrates a size nearly half of its RSIW counterpart while keeping the main propagation properties of the RSIW. A prototype of the wideband FRSIW filter with compact size has been designed and tested. The measurements show that the proposed wideband FRSIW filter has the advantages of low loss, compact size, and easy fabrication and integration with other electronic systems.