Patent ID: 9030277
Filing Date: 2015-05-12
Classification: H01P

Abstract:
1. A compact microwave distributed-element dual-mode bandpass filter comprising a dual-mode resonator and a signal input port and a signal output port coupled electrically to two open-circuited ends of the dual-mode resonator respectively; wherein, the dual-mode resonator comprises a main stripline with a center-loaded short-circuited stub, the main stripline is folded in both vertical and horizontal directions and is folded into a first layer, a second layer, a third layer and a fourth layer from top to bottom in the vertical direction which connected sequentially through main stripline connecting metallized through-holes, and the center-loaded short-circuited stub comprises a branch stripline and a short-circuited stub connecting metallized through-hole connected to actual ground; a symmetrical plane is provided between the second layer and the third layer, while the first layer and the fourth layer are symmetrical to each other relative to the symmetrical plane, the second layer and the third layer are symmetrical to each other relative to the symmetrical plane as well; the center-loaded short-circuited stub is located on the symmetrical plane, and the symmetrical plane can be a virtual ground at odd-mode resonant frequency.