Patent ID: 7358464

Claim:
A method for temperature measurement in a household appliance, comprising the steps: a) generating, using an electrical processing unit of the household appliance, a high-frequency electromagnetic excitation wave of a predefined transmit frequency, the transmit frequency being in a frequency band including temperature-dependent resonant frequencies that occur in a surface wave device incorporated in a temperature measuring probe and which frequencies respectively correspond to temperatures expected at the temperature measuring probe during operation of the household appliance; b) during a first phase, wirelessly transmitting the excitation wave to the surface wave device; c) during a second phase following the first phase, wirelessly transmitting to the processing unit an electromagnetic response wave generated by the excitation wave in the surface wave device; d) during the second phase, measuring, in an evaluation circuit of the processing unit, a signal level of a response signal generated from the response wave, and storing the signal level and the associated transmit frequency in a memory of the processing unit; e) repeating steps a)-d) for at least one additional different transmit frequency selected from the frequency band; f) comparing at least the signal level of a current measurement to the signal level of a previous measurement so as to determine the higher signal level; and g) determining a current temperature of the surface wave device by selecting the transmit frequency associated with the higher signal level.