Combiner with common port and double-layer cavity

The present invention relates to a combiner with a common port and a double-layer cavity, comprising a cavity, a spacer plate separating the cavity into an upper-layer cavity and a lower-layer cavity, a common port and a plurality of signal ports distributed at two sides of the cavity, and a first coupling disk, wherein the upper-layer cavity and the lower-layer cavity are respectively provided with a plurality of filtering paths, and are respectively provided with an upper common resonant column and a lower common resonant column at positions close to the common port; and the spacer plate is provided with a first coupling hole at a position close to the common port, and the first coupling disk is provided at the first coupling hole and is connected to the common port. Thus, a signal is coupled from the common port to an upper-layer and a lower-layer filtering path through the first coupling disk, thereby realising the port bandwidth of the upper-layer and the lower-layer filtering path. The combiner of the present invention has the advantages of a low insertion loss, a small volume, and being convenient for machining.