No abstract

Described is a zero power transceiver that is designed to receive a low-power RF signal at a fundamental frequency, double the frequency with high efficiency, and retransmit the second harmonic. The specific emphasis of this reported work was to demonstrate a means of imparting amplitude modulation onto the retransmitted harmonic in response to some environmental stimulus -in this case a DC bias voltage -to facilitate use of the transceiver in wireless sensing applications. The 1.3/2.6 GHz transceiver zero-bias conversion efficiency is approximately 2% (−17 dB) at received input power levels in the micro-Watt range. A change in the conversion efficiency of 10 dB per 100 mV is achieved through DC biasing of the multiplier.Introduction: The development of wireless sensors for remote monitoring is an active field of research with a broad range of applications. Areas involving security, intelligence, structural health monitoring, and tracking will be influenced by the continued development of remote sensor technology in the coming years. Efforts have been made to create efficient, low-cost and low-powered wireless devices for use in sensor networks in such fields.Background: Low-power remote sensors are continuously developing for sensing and monitoring applications, including miniaturised low-power embedded sensors and active acoustic wave transducers for infrastructure monitoring [1,2]. Harmonic transceivers utilising harmonic radar have been employed in sensor networks -incorporating a receiver that is tuned to the second harmonic of the transmitter [3]. Passive surface acoustic wave (SAW) technology has also proven to be useful in low power sensing [4], in particular, passive wireless SAW sensors for use in structural health monitoring of motor vehicles [5] and in-space vehicles [6].