Impedance matching circuit (100, 100') able to perform a simultaneous impedance matching between the generator and the load for a power supply signal having at least one first frequency, one second frequency, and one third frequency, distinct from one another, said circuit comprising: - an impedance matching stage able to perform the impedance matching between the generator and the load for the first frequency, this stage having a circuit comprising at least one tuning impedance (Z TUNE) mounted in series between the generator and the load and a load impedance (Z LOAD) mounted between the generator and a ground, and - at least one pair of additional stages (S2, S'2) able to perform the simultaneous impedance matching between the generator and the load for the second frequency, said pair of additional stages (S2, S'2) comprising: - a first additional stage having a load circuit mounted in parallel with the load impedance (Z LOAD) of the impedance matching stage, said load circuit comprising at least one inductance (L load2) and a capacitor (C load2) mounted in series, and - a second additional stage (S'2) having a tuning circuit (C'2) mounted in series with the tuning impedance (Z TUNE) of the impedance matching stage, said tuning circuit (C'2) comprising at least one inductance (L' tune2) and a capacitor (C' tune2) mounted in parallel, the impedance matching stage being moreover mounted between the first additional stage and the second additional stage (S'2), said circuit being characterised in that it comprises at least one additional pair of additional stages (S3, S'3) able to perform the simultaneous impedance matching, between the generator and the load for a third frequency, distinct from said first and second frequencies, said at least one additional pair of additional stages (S3, S'3) having: - a supplementary first additional stage having a load circuit mounted in parallel with the load impedance (Z TUNE) of the impedance matching stage, said load circuit comprising at least one inductance (L load3) and a capacitor (C load3) mounted in series, - a supplementary second additional stage (S'3) having a tuning circuit (C'3) mounted in series with the tuning impedance (Z TUNE) of the impedance matching stage, said tuning circuit (C'3) comprising at least one inductance (L' tune3) and a capacitor (C' tune3) mounted in parallel, the assembly formed by the impedance matching stage as well as by the pair of additional stages (S2, S'2) being moreover mounted between the supplementary first additional stage and the supplementary second additional stage (S'3). - an impedance matching stage able to perform the impedance matching between the generator and the load for the first frequency, this stage having a circuit comprising at least one tuning impedance (Z TUNE) mounted in series between the generator and the load and a load impedance (Z LOAD) mounted between the generator and a ground, and - at least one pair of additional stages (S2, S'2) able to perform the simultaneous impedance matching between the generator and the load for the second frequency, said pair of additional stages (S2, S'2) comprising: - a first additional stage having a load circuit mounted in parallel with the load impedance (Z LOAD) of the impedance matching stage, said load circuit comprising at least one inductance (L load2) and a capacitor (C load2) mounted in series, and - a second additional stage (S'2) having a tuning circuit (C'2) mounted in series with the tuning impedance (Z TUNE) of the impedance matching stage, said tuning circuit (C'2) comprising at least one inductance (L' tune2) and a capacitor (C' tune2) mounted in parallel, - a first additional stage having a load circuit mounted in parallel with the load impedance (Z LOAD) of the impedance matching stage, said load circuit comprising at least one inductance (L load2) and a capacitor (C load2) mounted in series, and - a second additional stage (S'2) having a tuning circuit (C'2) mounted in series with the tuning impedance (Z TUNE) of the impedance matching stage, said tuning circuit (C'2) comprising at least one inductance (L' tune2) and a capacitor (C' tune2) mounted in parallel, - a supplementary first additional stage having a load circuit mounted in parallel with the load impedance (Z TUNE) of the impedance matching stage, said load circuit comprising at least one inductance (L load3) and a capacitor (C load3) mounted in series, - a supplementary second additional stage (S'3) having a tuning circuit (C'3) mounted in series with the tuning impedance (Z TUNE) of the impedance matching stage,