Apparatus for sensing the temperature of an object

A method of operating an apparatus for sensing temperature of an object, wherein the apparatus comprises a sensing element having a resonant circuit, a detection unit physically unconnected with the sensing element, and a control unit, wherein the sensing element is configured to be inserted into or placed adjacent to the object, and the resonant circuit has a temperature-dependent resonant frequency and comprises a capacitor which comprises a ceramic capacitor that has a temperature coefficient in a predetermined range, and wherein the method comprises:

• interfacing the detection unit with the resonant circuit to receive a response associated with a current resonant frequency of the resonant circuit;
• determining, by the control unit, the current resonant frequency of the resonant circuit based on the received response;
• and
• determining, by the control unit, the temperature of the object based on the determined current resonant frequency of the resonant circuit,
• wherein the detection unit comprises a transmitter-receiver coil, and wherein interfacing the detection unit with the resonant circuit comprises controlling the transmitter-receiver coil to perform a frequency sweep to excite the resonant circuit in the sensing element,
• wherein performing the frequency sweep comprises performing a stepped sweep which includes a plurality of discrete steps each associated with a different frequency band, and
• wherein the method further comprises transmitting, by the resonant circuit, a response signal for each step in the sweep,
• and wherein determining the current resonant frequency of the resonant circuit comprises processing the response signals to determine the current resonant frequency.