摘要 |
<p>A radio system for sensing the spatial configuration of a physical object comprising a transmitter (102) which sends a query message to a transponder (104) having at least one antenna (106). A radio frequency shield (108) is moveably interposable between the transmitter and one or more antennas and thereby attenuates the signal strength of the query message received at an antenna. In any state of spatial configuration of the physical object, the transponder is able to receive the query message and, in reply, send a response message containing data determined according to the signal strength of the query message received at the one or more antennas.</p> |