Negative coupling structure applied in a dielectric waveguide filter

A negative coupling structure applied in a dielectric waveguide filter, comprising:

• a dielectric body, a plurality of tuning holes and the negative coupling structure disposed on the dielectric body, and the negative coupling structure being an elongated blind hole formed on a first surface of the dielectric body, and the negative coupling structure being formed between two adjacent tuning holes of the plurality of tuning holes, and the plurality of tuning holes being blind holes disposed on the first surface of the dielectric body or on a second surface opposite to the first surface, and the negative coupling structure comprising:
• a first coupling portion, defined in the dielectric body, and serving as a bottom wall of the elongated blind hole;
• a second coupling portion, defined in the dielectric body, and serving as a side wall of one of the two ends of the elongated blind hole;
• and
• a common coupling portion, coupled to the first coupling portion and the second coupling portion, defined as one of the two ends of the elongated blind hole, and coupled to connecting wall of the bottom wall and the side wall.