Cavity filter

A cavity filter, comprising:

• a housing with an accommodating cavity, an input through hole and an output through hole, the input through hole and the output through hole communicating with the accommodating cavity;
• an input resonator located in the accommodating cavity and disposed on the housing, the input resonator comprising a first sheet resonant body, an input end and a first branch, the input end extending outward from one side of the first sheet resonance body, the first branch extending outward from a same side of the input end on the first sheet resonant body and/or the first branch extending outward from the input end, the input end extending out of the housing through the input through hole;
• and
• an output resonator located in the accommodating cavity and disposed on the housing, the output resonator comprising a second sheet resonant body, an output end and a second branch, the output end extending outward from one side of the second sheet resonance body, the second branch extending outward from a same side of the output end on the second sheet resonant body and/or the second branch extending outward from the output end, the output end extending out of the housing through the output through hole;
• wherein a length of the first branch and a length of the second branch are a quarter wavelength of a resonant frequency of the cavity filter.