An adjustable radiofrequency filter in planar technology comprises at least one dielectric substrate and n resonators R1, R2, . . . Ri, . . . Rj, . . . Rk, . . . Rn integrated into the substrate, and each resonator comprises, on a principal plane PL of the substrate, a succession of segments t1, t2, . . . tq, . . . tp of planar transmission lines each having two ends, p being the number of segments of planar transmission lines of the resonator Ri considered, p being equal to or greater than 2, q being the rank of the segment, an end of a segment tq of a resonator Ri being opposite and separated by a distance d from an end of the next segment t(q+1) of the same resonator Ri, the opposite ends of the successive segments of a resonator Rq being linked by an electrical link which locally raises the characteristic impedance of the resonator Ri considered.