Patent ID: 8508317

Claim:
A broadband coupling filter, comprising: a substrate, comprising a first layer, a second layer and a third layer, wherein the second layer is between the first layer and the third layer; a first signal terminal, formed in the first layer of the substrate; a second signal terminal, formed in the first layer of the substrate; a third signal terminal, formed in the third layer of the substrate; a fourth signal terminal, formed in the third layer of the substrate; a grounding plate, formed in the second layer of the substrate, and having a hole; a first block transmission line, formed at a position corresponding to the hole in the first layer of the substrate, and coupled to the first signal terminal and the second signal terminal; a second block transmission line, formed at a position corresponding to the hole in the third layer of the substrate, and directly coupled to the third signal terminal and the fourth signal terminal, and having a shape identical to a shape of the first block transmission line; and a connection unit, formed in the third layer of the substrate, for connecting the third signal terminal and the fourth signal terminal; wherein the first signal terminal is utilized for receiving a signal, and the second signal terminal is utilized for outputting a filtering result of the signal.