Passive wireless sensors for chemical and biological agents and wireless systems including the passive wireless sensors

摘要

Wireless sensors for detection of an analyte may include a sensor receiving antenna configured to receive interrogation pulses having an interrogation frequency, a DC converter, a relaxation oscillator circuit electrically, and a sensor transmitting antenna. The relaxation oscillator circuit may include a capacitance element that defines a response-pulse frequency of the wireless sensor. The capacitance element may include an interdigitated capacitor coated with a detection layer of a functional material having a dielectric constant that defines the dielectric constant of the interdigitated capacitor. This dielectric constant changes when the functional material is exposed to the analyte, thereby changing the response-pulse frequency of the relaxation oscillator circuit to an analyte-exposure frequency indicative of the exposure of the functional material to the analyte. Wireless systems for detecting an analyte may include a wireless sensor that communicates with an interrogation module.

主权项

1. A wireless sensor for detection of an analyte, the wireless sensor comprising:
a sensor receiving antenna configured to receive interrogation pulses having an interrogation frequency; a DC converter electrically coupled to the sensor receiving antenna; a relaxation oscillator circuit electrically coupled to the DC converter, the relaxation oscillator circuit comprising a capacitance element that defines a response-pulse frequency of the wireless sensor; and a sensor transmitting antenna electrically coupled to the relaxation oscillator circuit, the sensor transmitting antenna being configured to receive response pulses from the relaxation oscillator circuit and to transmit the response pulses at the response-pulse frequency;wherein:
the capacitance element of the relaxation oscillator circuit comprises an interdigitated capacitor comprising a first capacitor plate including a plurality of parallel first-plate fingers and a second capacitor plate including a plurality of second-plate fingers, a capacitor-finger gap defined between the first-plate fingers and the second-plate fingers, each of the first-plate fingers extending between two of the second-plate fingers to form an interdigitated structure of the interdigitated capacitor; the interdigitated capacitor is coated with a detection layer of a functional material having a detection-layer dielectric constant that defines an IDC dielectric constant of the interdigitated capacitor, the detection layer completely covering the interdigitated capacitor and filling the capacitor-finger gap; and the detection-layer dielectric constant changes when the functional material is exposed to the analyte, thereby changing the response-pulse frequency of the relaxation oscillator circuit to an analyte-exposure frequency indicative of the exposure of the functional material to the analyte.