A Dual Band Semi-Passive Sensor Tag Based on the Technique of Electromagnetic Field Scavenging

Abstract

The study provides a dual band semi-passive sensor tag with one band used for delivering the information of interest, the other one for aggregating the power necessary for sensor head offset. The proposed sensor tag is a planar structure equipped with two radiators. The radiator1 is a planar inverse F-type metallic strip connected to RF/DC rectifier and grounding plane via, respectively, the feed and the short line. The radiator2 is an inverse L-type metallic strip connected to grounding plane directly. A RF/DC rectifier is set between the feed and the grounding plane, the offset output from which is exerted to the electrode of the sensor head fabricated by interdigited fingers with resistive load. The radiator1, the short line, the feed and the grounding plane form the first RF channel for delivering the information of interest; the radiator2, the sensor head, the feed and the RFin port in the RF/DC rectifier form the second channel for power scavenging and transmitting; while the RF/DC rectifier, the feed, the sensor head, the radiator2 and the grounding plane form the circuit of offset yielded and applied to the electrodes of the sensor head.