Detecting physical parameters

An apparatus for sensing the value of a physical parameter at a sensing location, the apparatus comprising:

• a transmitter element configured to generate and transmit a pulsed electromagnetic wave;
• a sensing element, galvanically isolated from the transmitter element and configured to be positioned at or adjacent to the sensing location, wherein:
• the sensing element comprises a capacitive element and a resistive element connected in a loop such that, responsive to the sensing element receiving the pulsed electromagnetic wave, the sensing element generates an oscillating electromagnetic wave that changes responsive to an impedance of the resistive element;
• and
• the resistive element is configured such that an impedance of the resistive element changes responsive to changes in the physical parameter in the vicinity of the sensing element;
• and
• a detection element, galvanically isolated from the sensing element, and configured to detect the oscillating electromagnetic wave and process the detected oscillating electromagnetic wave to estimate a value of the physical parameter at the sensing location.