A method for managing a microwave heating device wherein the microwave heating device comprises: - a heating chamber; - a signal generator, the signal generator being of the solid-state type and being able to generate sinusoidal signals with a fundamental harmonic frequency within the microwave range; - one or more radiating portions positioned in the heating chamber and supplied by the signal generator by means of a supply circuit, for radiating microwaves in the heating chamber; - the signal generator and the supply circuit being settable according to multiple operating configurations, each operating configuration having its own fundamental harmonic frequency; the method comprising: - a setting step in which the signal generator and the supply circuit are set according to a first operating configuration having a first fundamental harmonic frequency; and - a supply step in which the signal generator generates a first signal with the first fundamental harmonic frequency, which is transmitted by means of the supply circuit, and, according to the first operating configuration, to the one or more radiating portions according to a forward direction of propagation that goes from the signal generator to the one or more radiating portions; and wherein, during the supply step, the method also comprises: - a step of monitoring a second signal that propagates in the supply circuit according to a reflected direction of propagation that goes from the one or more radiating portions to the signal generator, and/or that is generated in the heating chamber; characterized by - a step of detecting the intensity of one or more harmonic components of said second signal, which have a frequency higher than the fundamental harmonic frequency; - a step of comparing the intensity detected with a critical reference value; and, - when the comparison step indicates that the intensity detected is higher than the critical reference value, a safety intervention step in which the supply step is interrupted or in which the operating configuration is changed, wherein the critical reference value is equal to 5-10 times the intensity of a third signal that propagates in the supply circuit according to the reflected direction of propagation and/or that is generated in the heating chamber in a reference operating condition. - a heating chamber; - a signal generator, the signal generator being of the solid-state type and being able to generate sinusoidal signals with a fundamental harmonic frequency within the microwave range; - one or more radiating portions positioned in the heating chamber and supplied by the signal generator by means of a supply circuit, for radiating microwaves in the heating chamber; - the signal generator and the supply circuit being settable according to multiple operating configurations, each operating configuration having its own fundamental harmonic frequency; - a setting step in which the signal generator and the supply circuit are set according to a first operating configuration having a first fundamental harmonic frequency; and - a supply step in which the signal generator generates a first signal with the first fundamental harmonic frequency, which is transmitted by means of the supply circuit, and, according to the first operating configuration, to the one or more radiating portions according to a forward direction of propagation that goes from the signal generator to the one or more radiating portions; and - a step of monitoring a second signal that propagates in the supply circuit according to a reflected direction of propagation that goes from the one or more radiating portions to the signal generator, and/or that is generated in the heating chamber; - a step of detecting the intensity of one or more harmonic components of said second signal, which have a frequency higher than the fundamental harmonic frequency; - a step of comparing the intensity detected with a critical reference value; and, - when the comparison step indicates that the intensity detected is higher than the critical reference value, a safety intervention step in which the supply step is interrupted or in which the operating configuration is changed,