| 摘要 |
A filter in which the overall size is reduced in plan view while utilizing a folded waveguide. The filter comprises a waveguide (B1) formed in a multilayer substrate (PC) while being surrounded by conductor layers (15, 17) arranged oppositely across a dielectric layer (A1) and a conductor wall constituted of conductors (TH) for conducting the conductor layers (15, 17), and a waveguide (B2) formed in the multilayer substrate (PC) along the waveguide (B1) while being surrounded by conductor layers (17, 21) and a conductor wall constituted of conductors (TH) for conducting the conductor layers (17, 21). Each waveguide (B1, B2) is closed at one end part on the same direction side along the longitudinal direction and coupled, at each end part, through a coupling window (31) arranged in the conductor layer (17). |
