The invention relates to the field of communication, and provides a filter, which comprises a first
resonator, the first
resonator at least has two
resonance modes of a TE mode and a TM mode, the first
resonator comprises a resonator shell and a
dielectric resonance piece arranged in the resonator shell, and the
dielectric resonance piece is connected to a first wall of the resonator shell; the filter further comprises a first
coupling structure arranged in the resonator shell, the two opposite ends of the first
coupling structure are both grounded, the first
coupling structure comprises a first coupling part and a second coupling part, one end of the second coupling part is connected to the end, away from the central axis of the
dielectric resonance piece, of the first coupling part, and the other end of the second coupling part is grounded. The first coupling part intersects in the circumferential direction of the
dielectric resonance part, and the second coupling part intersects in the radial direction of the
dielectric resonance part, so that a TE mode and a TM mode of the first resonator are coupled. According to the filter, the TE mode and the TM mode of the first resonator can be coupled through the first coupling structure which is simplified and optimized, the
coupling effect is good, and
simulation design of the filter can be facilitated.