Filter

1. A filter, comprising:

a filter frame in which a receiving space is formed;

at least two resonators disposed in the receiving space and distributed along a signal transmission path, adjacent resonators on the signal transmission path being coupled to each other, and each resonator including a body part and a bending part, wherein:

one end of the body part is grounded,

the bending part includes a head bending part and an end bending part, the head bending part being connected to the end bending part to form a resonator structure circulating in a counterclockwise or clockwise direction.

2. The filter according to claim 1 , wherein the bending part further includes at least one middle bending part, and the at least one middle bending part connects the head bending part and the end bending part to form the resonator structure circulating in the counterclockwise or clockwise direction.

3. The filter according to claim 1 , wherein the head bending part is formed by bending another end of the body part in one direction or two directions.

4. The filter according to claim 1 , further comprising:

at least one partition wall disposed in the filter, a coupling gap being formed between the partition wall and an inner wall of the filter frame.

5. The filter according to claim 4 , wherein the signal transmission path in the filter has a U-shape or an S-shape.

6. The filter according to claim 5 , wherein the partition wall is integrally formed with a middle section of the filter frame, and the signal transmission path in the filter has the U-shape.

7. The fitter according to claim 4 , wherein a plurality of partition walls spaced with each other are disposed within the filter, and two adjacent partition walls respectively form a coupling gap with a corresponding inner wall of two opposite inner walls of the filter frame, and the signal transmission path in the filter has an S-shape according to the partition wall.

8. The filter according to claim 4 , wherein the partition wall divides the receiving space into a plurality of receiving chambers, the partition wall is provided with a coupling opening, and two adjacent resonators in different receiving chambers are coupled to each other through the coupling opening to form a cross-coupling.

9. The filter according to claim 8 , wherein the body parts of two adjacent resonators in different receiving chambers are directly connected through the coupling opening to form inductive cross-coupling.

10. The filter according to claim 8 , wherein the bending parts of two adjacent resonators in different receiving chambers are spaced apart through the coupling opening to form capacitive cross-coupling.

11. The filter according to claim 1 , wherein the filter further comprises an upper cover plate arranged at an upper end of the filter frame and a lower cover plate arranged at a lower end of the filter frame, the upper cover and the lower cover encapsulate the receiving space, and a thickness of the bending part of one or both of the at least two resonators is greater than a thickness of the body part in a direction perpendicular to the upper and lower cover plates.

12. The filter according to claim 4 , wherein: the partition wall is integrally formed with the inner wall of the filter frame.

13. The filter according to claim 12 , wherein: the body part of the resonator is integrally formed with the partition wall and grounded.

14. The filter according to claim 12 , wherein: the body part of the resonator is integrally formed with the inner wall of the filter frame and grounded.