Object detector

A method of object detection using an object detector comprising:

• an object detector, comprising:
• a transmitter arranged to generate a transmit signal;
• a transmit loop antenna, coupled to said transmitter and arranged to radiate said transmit signal;
• and a receive loop antenna arranged to generate a receive signal from received radio waves;
• and a signal detector, coupled to said receive loop antenna and said transmitter, the method comprising:
• generating and transmitting said transmit signal;
• receiving, at said receive loop antenna, radio waves including said radiated transmit signal and, in the presence of objects within range of the device which reradiate said transmit signal, one or more radio waves reradiated by such objects;
• generating a receive signal, at an output of said receive loop antenna, including a component corresponding to said transmit signal and, in the presence of reradiated radio waves, one or more components corresponding to said reradiated radio waves;
• and
• detecting, using said signal detector, changes in the amplitude and/or phase of said receive signal which are due to changes in said components corresponding to said reradiated radio waves.