Cross-coupled filter

1. A cross-coupled filter, wherein:

the cross-coupled filter comprises a resonant structure including a plurality of columns of resonant units, each column of resonant units including at least two resonators;

a dominant coupling mode of a coupling between two adjacent resonators in a same column is electrical coupling or magnetic coupling;

dominant coupling modes of a plurality of groups of two adjacent resonators in the same column alternate between electrical coupling and magnetic coupling;

a dominant coupling mode of a coupling between two adjacent resonators in adjacent columns is electrical coupling or magnetic coupling;

dominant coupling modes of a plurality of groups of two resonators of two adjacent columns alternate between electrical coupling and magnetic coupling, to form at least a set of cross-coupling.

2. The cross-coupled filter according to claim 1 , wherein the resonant structure is integrally formed, the resonant structure further comprises a frame, and the resonant units are integrally formed on the frame.

3. The cross-coupled filter according to claim 1 , wherein each of the resonators has an overall cylindrical appearance, and comprises a resonant head and a resonant tail opposite to each other, and a width of the resonant head is greater than a width of the resonant tail.

4. The cross-coupled filter according to claim 3 , wherein the filter further comprises a cover arranged on the resonators, and the cover comprises a top cover arranged on an upper end of the resonant structure and a bottom cover arranged on a lower end of the resonant structure to form a closed filter cavity.

5. The cross-coupled filter according to claim 4 , wherein the top cover comprises a plurality of protrusions and at least a shielding post, wherein,

each protrusion is formed by extending from an end face of the top cover close to the resonant structure toward the resonant structure, and a position of the protrusion on the top cover corresponds to a position of the resonant head of the resonator on the resonant structure; and

the shielding post is located between two adjacent resonators.

6. The cross-coupled filter according to claim 4 , wherein the bottom cover comprises a plurality of protrusions and at least a shielding post, wherein,

each protrusion is formed by extending from an end face of the bottom cover close to the resonant structure toward the resonant structure, and a position of the protrusion on the bottom cover corresponds to a position of the resonant head of the resonator on the resonant structure; and

the shielding post is located between two adjacent resonators.

7. The cross-coupled filter according to claim 3 , wherein the resonant tails of two adjacent resonators in the same column are connected to form the dominant coupling mode of magnetic coupling, or the resonant heads are placed face-to-face to form the dominant coupling mode of electrical coupling, and distributed positions of the plurality of groups of adjacent resonators in the same column alternate between face-to-face of the resonant heads and connection of the resonant tails.

8. The cross-coupled filter according to claim 1 , wherein at least one partition wall is disposed between two adjacent columns of the resonant units and configured to adjust the dominant coupling mode between two adjacent resonators of the two adjacent columns of the resonant units to electrical coupling or magnetic coupling.

9. The cross-coupled filter according to claim 1 , further comprising:

at least one structural member configured to enhance an amount of cross-coupling between the resonators, and each structural member connects two resonators that are cross-coupled.

10. The cross-coupled filter according to claim 4 , wherein the cover further comprises a plurality of tuning screws and a plurality of coupling adjustment screws, the resonant head is provided with a tuning hole, and each tuning screw passes through the cover and extends into the tuning hole of the corresponding resonant head to adjust a resonant frequency of the corresponding resonator; each coupling adjustment screw passes through the cover and extends to a position between two adjacent resonators to adjust an amount of coupling between the corresponding two adjacent resonators.

11. The cross-coupled filter according to claim 1 , wherein the plurality of columns of resonant units are distributed along a signal transmission path, and the signal transmission path is U-shaped, S-shaped, or a curve path formed by a plurality of continuous U-shapes or continuous S-shapes.