Filter and wireless network device

A wireless network device, comprising a filter, which comprises

• a filter body with a straight-line groove body, and resonant cavities disposed in the straight-line groove body of the filter body, wherein one resonator is disposed in each of the resonant cavities;
• a cover fastened to the straight-line groove body;
• an input port and an output port, the input port disposed on the cover, and the output port disposed on the filter body, wherein the input port is inductively coupled to one of the resonant cavities, the output port is inductively coupled to another one of the resonant cavities, and neighboring resonant cavities are inductively coupled;
• and wherein at least one of the input port or the output port is connected to a set of additional resonant cavities, and the set of additional resonant cavities comprises:
• a first additional resonant cavity coupled to the input port or the output port, and a second additional resonant cavity in signal coupling to the first additional resonant cavity.