PASSIVE WIRELESS SENSORS FOR CHEMICAL AND BIOLOGICAL AGENTS AND WIRELESS SYSTEMS INCLUDING THE PASSIVE WIRELESS SENSORS

• US 20140062666A1
• Filed: 07/24/2013
• Published: 03/06/2014
• Est. Priority Date: 07/25/2012
• Status: Active Grant

• Current Assignee: University of Dayton
• Original Assignee: University of Dayton
• Inventors: Patterson, Mark Alan
• Granted Patent: US 9,177,185 B2
• Time in Patent Office: Days
• US Class Current: 340/10.1
• CPC Class Codes: G01N 2291/0255 (Bio)chemical reactions, e.g. on biosensors
• CPC Class Codes: G01N 2291/0256 Adsorption, desorption, surface mass change, e.g. on biosensors
• CPC Class Codes: G01N 33/0031 comprising two or more sensors, e.g. a sensor array
• CPC Class Codes: G06K 19/0716 at least one of the integrated circuit chips comprising a sensor or an interface to a sensor
• CPC Class Codes: G06K 7/10366 the interrogation device being adapted for miscellaneous applications

Abstract

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.

Claims

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;

at least 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; 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.

2. The wireless sensor of claim 1, wherein the functional coating material is a material that is chemically reactive with the analyte or onto which the analyte physically absorbs or is adsorbed.

3. The wireless sensor of claim 1, wherein the functional material is a polymer that is permeable to the analyte.

4. The wireless sensor of claim 1, wherein the functional coating material is chosen from silk, sulfonated tetrafluoroethylene, acrylic polymers, poly(methylmethacrylate), polystyrene, poly(vinyl chloride), poly(2-chloroethyl vinyl ether), polyacrylamide, polyfluoropolyol (FPOL), poly(ethylenimine) (XPEI), poly(ethylene phthalate) (PEPH), poly(epichlorohydrin) (PECH), poly(isobutylene) (XPIB), phenylmethyl-diphenyisiloxane copolymers, polybis(cyanopropyl)siloxane, poly(ethylene maleate), and poly(butyl acrylate).

5. The wireless sensor of claim 1, wherein the relaxation oscillator circuit further comprises a plurality of resistors and a unijunction transistor, wherein the plurality of resistors, the unijunction transistor, and the capacitance element together define the response-pulse frequency of the relaxation oscillator circuit.

6. The wireless sensor of claim 1, wherein the sensor receiving antenna, the DC converter, the relaxation oscillator circuit, and the sensor transmitting antenna are provided on a sensor-substrate surface of a sensor substrate.

7. The wireless sensor of claim 6, wherein the sensor receiving antenna and the sensor transmitting antenna are coils.

8. The wireless sensor of claim 7, wherein the sensor receiving antenna defines an outer periphery of the wireless sensor on the sensor-substrate surface.

9. The wireless sensor of claim 7, wherein the DC converter, the relaxation oscillator circuit, and the sensor transmitting antenna are disposed on the sensor-substrate surface inside an inner perimeter of the sensor receiving antenna.

16. The wireless system of claim 1, wherein the interrogator card comprises:

an interrogator transmitting antenna configured to send the interrogation pulses; and

an interrogator receiving antenna configured to receive the response pulses transmitted from the wireless sensor.

17. The wireless system of claim 16, wherein:

the interrogator transmitting antenna and the interrogator receiving antenna are coils provided on an interrogator-substrate surface of an interrogator substrate; and

the sensor receiving antenna and the sensor transmitting antenna are coils provided on a sensor-substrate surface of a sensor substrate.

18. The wireless system of claim 17, wherein:

the interrogator transmitting antenna of the interrogator card has an interrogator transmitting-antenna geometry that substantially matches a sensor receiving-antenna geometry of the sensor receiving antenna of the wireless sensor; and

the interrogator receiving antenna of the interrogator card has a interrogator receiving-antenna geometry that substantially matches a sensor transmitting-antenna geometry of the sensor transmitting antenna of the wireless sensor.

19. The wireless system of claim 16, wherein:

the interrogator transmitting antenna and the interrogator receiving antenna are coils provided on an interrogator-substrate surface of an interrogator substrate;

the interrogator receiving antenna defines an outer periphery of the interrogator card on the interrogator-substrate surface;

the interrogator transmitting antenna is disposed on the substrate surface inside an inner perimeter of the interrogator receiving antenna;

the sensor receiving antenna and the sensor transmitting antenna are coils provided on a sensor-substrate surface of a sensor substrate;

the sensor receiving antenna defines an outer periphery of the wireless sensor on the sensor-substrate surface; and

the DC converter, the relaxation oscillator circuit, and the sensor transmitting antenna are disposed on the sensor-substrate surface inside an inner perimeter of the sensor receiving antenna.

20. The wireless system of claim 16, wherein the interrogator module further comprises:

a radio-frequency generator that generates the interrogation pulses, the radio-frequency generator being electrically coupled to the interrogator transmitting antenna; and

a radio-frequency receiver that determines the response-pulse frequency of incoming response pulses, the radio-frequency receiver being electrically coupled to the interrogator receiving antenna.

10. A wireless system for detecting an exposure of a wireless sensor to an analyte, the wireless system comprising an interrogator module including an interrogator card that sends interrogation pulses having an interrogation frequency to a wireless sensor and receives response pulses having a response-pulse frequency from the wireless sensor, wherein the wireless sensor comprises:

a sensor receiving antenna configured to receive the interrogation pulses;

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 the response-pulse frequency; 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 to the interrogator module at the response-pulse frequency;

wherein;

the capacitance element of the relaxation oscillator circuit comprises an interdigitated capacitor;

at least 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; 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.

11. The wireless system of claim 10, wherein the functional coating material is a material that is chemically reactive with the analyte or onto which the analyte physically absorbs or is adsorbed.

12. The wireless system of claim 10, wherein:

the functional material is hydrophilic and the analyte is hydrophilic;

or

the functional material is hydrophobic and the analyte is hydrophobic.

13. The wireless system of claim 10, wherein the analyte at least partially dissolves the functional material when the functional material is exposed to the analyte.

14. The wireless system of claim 10, wherein the functional coating material is chosen from silk, sulfonated tetrafluoroethylene, acrylic polymers, poly(methylmethacrylate), polystyrene, poly(vinyl chloride), poly(2-chloroethyl vinyl ether), polyacrylamide, polyfluoropolyol (FPOL), poly(ethylenimine) (XPEI), poly(ethylene phthalate) (PEPH), poly(epichlorohydrin) (PECH), poly(isobutylene) (XPIB), phenylmethyl-diphenyisiloxane copolymers, polybis(cyanopropyl)siloxane, poly(ethylene maleate), and poly(butyl acrylate).

15. The wireless system of claim 14, wherein the analyte is chosen from hydrocarbons, petroleum products, hydraulic fluid, gasoline, chlorine, mineral acids, volatile organics, pesticides, polychlorinated biphenyls (PCBs), herbicides, alkanes, alkenes, alkynes, dienes, alicyclic hydrocarbons, arenes, alcohols, ethers, ketones, aldehydes, carbonyls, carbanions, polynuclear aromatics, organic derivatives, biomolecules, sugars, isoprenes, isoprenoids, fatty acids, and dimethyl methylphosphonate.