Band-pass filter for a microwave which can be frequency-tuned and which has a central frequency (fc), the microwave being propagated along an axis Z, the filter comprising - an input resonator comprising a metal input cavity and a dielectric input element, placed inside the input cavity and capable of disrupting the resonance mode of the microwave in the input cavity, - an output resonator comprising a metal output cavity and a dielectric output element, placed inside the output cavity and capable of disrupting the resonance mode of the microwave in the output cavity, - an input excitation means which has an elongate shape along the axis Z and which penetrates the input cavity in order to allow the microwave to penetrate the input cavity, - an output excitation means which has an elongate shape on the axis Z and which penetrates the output cavity in order to allow the microwave to exit the output cavity, - the input resonator and the output resonator being coupled, and - the dielectric input element and the dielectric output element have a recess (41, 42), - the input excitation means penetrates inside the recess of the dielectric input element so that the dielectric input element disrupts the electromagnetic field close to the input excitation means, - the output excitation means penetrates inside the recess of the dielectric output element so that the dielectric output element disrupts the electromagnetic field close to the output excitation means, - the dielectric input element is capable of carrying out a rotation about an input rotation axis, the recess being suitable for allowing the rotation of the dielectric element while keeping the input excitation element inside the recess, - the dielectric output element is capable of carrying out a rotation about an output rotation axis, the recess being suitable for allowing the rotation of the dielectric element while keeping the output excitation element inside the recess, - each dielectric element (E1, EN) has a flat shape having a height less by at least a factor of 3 than the smallest external dimension in a plane perpendicular to the direction supporting the height, - the rotations of the dielectric elements (E1, EN) allowing the modification of the central frequency of the filter. - an input resonator comprising a metal input cavity and a dielectric input element, placed inside the input cavity and capable of disrupting the resonance mode of the microwave in the input cavity, - an output resonator comprising a metal output cavity and a dielectric output element, placed inside the output cavity and capable of disrupting the resonance mode of the microwave in the output cavity, - an input excitation means which has an elongate shape along the axis Z and which penetrates the input cavity in order to allow the microwave to penetrate the input cavity, - an output excitation means which has an elongate shape on the axis Z and which penetrates the output cavity in order to allow the microwave to exit the output cavity, - the input resonator and the output resonator being coupled, and - the dielectric input element and the dielectric output element have a recess (41, 42), - the input excitation means penetrates inside the recess of the dielectric input element so that the dielectric input element disrupts the electromagnetic field close to the input excitation means, - the output excitation means penetrates inside the recess of the dielectric output element so that the dielectric output element disrupts the electromagnetic field close to the output excitation means, - the dielectric input element is capable of carrying out a rotation about an input rotation axis, the recess being suitable for allowing the rotation of the dielectric element while keeping the input excitation element inside the recess, - the dielectric output element is capable of carrying out a rotation about an output rotation axis, the recess being suitable for allowing the rotation of the dielectric element while keeping the output excitation element inside the recess, - each dielectric element (E1, EN) has a flat shape having a height less by at least a factor of 3 than the smallest external dimension in a plane perpendicular to the direction supporting the height, - the rotations of the dielectric elements (E1, EN) allowing the modification of the central frequency of the filter.