System, method, and sensors for sensing physical properties

摘要: Several sensors are provided for determining one of a number physical roperties including pressure, temperature, chemical species, and other conditions. In general, the feature resonant circuit with an inductor coil which is electromagnetically coupled to transmitting antenna. When excitation signal applied antenna, current induced in sensor circuit. This oscillates at frequency The bandwidth determined using impedance analyzer, receiving antenna system, or chirp interrogation system. may further be simple analog transmitter. constructed so that either circuit, both, made depend upon properties such as presence condition specific environment. calculated from determined.