High-frequency filter

A filter for providing an analog signal with a predetermined bandwidth, the filter comprising:

• a printed circuit board having a printed circuit thereon, the printed circuit including a signal circuit having a plurality of resonators magnetically or electrically coupled with each other, an input terminal and an output terminal, and a grounding circuit electrically connected to ground and arranged around the resonators;
• wherein the resonators comprises a first resonator electrically connected to the input terminal and a second resonator electrically connected to the output terminal;
• a tuner including a shell made of a conductive metal, electrically connected to the grounding circuit and covered over the resonators such that an isolation chamber is defined between the shell and the resonators, and an adjustment member movably mounted in the shell and moveable relative to the resonators to adjust the dimension of the isolation chamber so as to further adjust a range of the bandwidth of the analog signal.