Resonant circuit with characteristic stabilized impedance, comprising an input terminal (Pe) and an output terminal (Ps), and at least: - a group of N piezoelectric resonators, where N > 1, said resonators having the same resonance frequency and the same antiresonance frequency, said resonators being arranged in parallel such that the sum of their elementary static capacitances is equal to a static capacitance of said group; - a first impedance matching element (Cs) having a non-zero reactance and a second impedance matching element (Cp) having a non-zero reactance, the first impedance matching element being in series with said group of N resonators, and the second impedance matching element being in parallel with said group of N resonators, said resonant circuit comprising: - first means for controlling said group of resonators, arranged to enable the static capacitance (C 0) of said group to be fixed at a first value; - second control means, arranged to enable the impedance of the first impedance matching element and that of the second impedance matching element to be fixed at second values; said first and second values being such that: the triplet of values: static capacitance of said group/impedance of the first impedance matching element/impedance of the second impedance matching element (C 0, Cs, Cp) determines for the impedance Z of the assembly formed by said group, said first impedance matching element and said second matching element, a following triplet of parameters: ∘ a characteristic impedance Z c of said assembly; ∘ the resonance frequency ω r of said assembly; ∘ the antiresonance frequency ω a of said assembly; in order to stabilize the impedance of said circuit at a chosen characteristic impedance. - a group of N piezoelectric resonators, where N > 1, said resonators having the same resonance frequency and the same antiresonance frequency, said resonators being arranged in parallel such that the sum of their elementary static capacitances is equal to a static capacitance of said group; - a first impedance matching element (Cs) having a non-zero reactance and a second impedance matching element (Cp) having a non-zero reactance, the first impedance matching element being in series with said group of N resonators, and the second impedance matching element being in parallel with said group of N resonators, said resonant circuit comprising: - first means for controlling said group of resonators, arranged to enable the static capacitance (C 0) of said group to be fixed at a first value; - second control means, arranged to enable the impedance of the first impedance matching element and that of the second impedance matching element to be fixed at second values; the triplet of values: static capacitance of said group/impedance of the first impedance matching element/impedance of the second impedance matching element (C 0, Cs, Cp) determines for the impedance Z of the assembly formed by said group, said first impedance matching element and said second matching element, a following triplet of parameters: ∘ a characteristic impedance Z c of said assembly; ∘ the resonance frequency ω r of said assembly; ∘ the antiresonance frequency ω a of said assembly; ∘ a characteristic impedance Z c of said assembly; ∘ the resonance frequency ω r of said assembly; ∘ the antiresonance frequency ω a of said assembly; in order to stabilize the impedance of said circuit at a chosen characteristic impedance.