Passive wireless antenna sensor for strain, temperature, crack and fatigue measurement
First Claim
1. A method of monitoring a condition of a structure using a passive wireless antenna sensor having a known resonant frequency when mounted on the structure, comprising:
- transmitting a series of radio frequency (RF) signals with sweeping frequencies around the known resonant frequency to the passive wireless antenna sensor, wherein the passive wireless antenna sensor comprises an antenna comprising a dielectric substrate disposed between an antenna pattern and a ground plane such that a change in the condition of the structure being monitored will directly cause a change in at least one characteristic of the antenna, wherein the characteristic includes a crack in the ground plane;
receiving a backscattered signal from the passive wireless antenna sensor, wherein the backscattered signal comprises an antenna backscattered signal and a structure backscattered signal, and the antenna backscattered signal is delayed with respect to the structure backscattered signal, such that the structure backscattered signal is received before the antenna backscattered signal;
determining a resonant frequency of the passive wireless antenna sensor based on the antenna backscattered signal; and
using a digital signal processor, determining the condition of the structure by comparing the determined resonant frequency of the passive wireless antenna sensor to the known resonant frequency of the passive wireless antenna sensor, whereby a change in the resonant frequency of the passive wireless antenna sensor indicates a change in the condition of the structure, including a detected crack in the structure.
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Accused Products
Abstract
An apparatus and method is provided for monitoring a condition of a structure using a passive wireless antenna sensor having a known resonant frequency when mounted on the structure. A series of radio frequency signals are transmitted with sweeping frequencies around the known resonant frequency to the passive wireless antenna sensor. The passive wireless antenna sensor includes a dielectric substrate disposed between an antenna pattern and a ground plane such that a change in the condition of the structure will cause a change in one or more characteristics of the passive wireless sensor. A signal is received from the passive wireless antenna sensor and a resonant frequency of the passive wireless antenna sensor is determined based on the received signal. The determined resonant frequency is then compared to the known resonant frequency, whereby a change in the resonant frequency indicates a change in the condition of the structure.
19 Citations
25 Claims
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1. A method of monitoring a condition of a structure using a passive wireless antenna sensor having a known resonant frequency when mounted on the structure, comprising:
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transmitting a series of radio frequency (RF) signals with sweeping frequencies around the known resonant frequency to the passive wireless antenna sensor, wherein the passive wireless antenna sensor comprises an antenna comprising a dielectric substrate disposed between an antenna pattern and a ground plane such that a change in the condition of the structure being monitored will directly cause a change in at least one characteristic of the antenna, wherein the characteristic includes a crack in the ground plane; receiving a backscattered signal from the passive wireless antenna sensor, wherein the backscattered signal comprises an antenna backscattered signal and a structure backscattered signal, and the antenna backscattered signal is delayed with respect to the structure backscattered signal, such that the structure backscattered signal is received before the antenna backscattered signal; determining a resonant frequency of the passive wireless antenna sensor based on the antenna backscattered signal; and using a digital signal processor, determining the condition of the structure by comparing the determined resonant frequency of the passive wireless antenna sensor to the known resonant frequency of the passive wireless antenna sensor, whereby a change in the resonant frequency of the passive wireless antenna sensor indicates a change in the condition of the structure, including a detected crack in the structure. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13)
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14. An apparatus for monitoring a condition of a structure, comprising:
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a transmitter for transmitting a series of radio frequency (RF) signals with sweeping frequencies around a known resonant frequency to a passive wireless antenna sensor, wherein the passive wireless antenna sensor has the known resonant frequency when mounted on the structure and comprises an antenna comprising a dielectric substrate disposed between an antenna pattern and a ground plane such that a change in the condition of the structure being monitored will directly cause a change in at least one characteristic of the antenna, including a crack in the ground plane; a receiver for receiving a backscattered signal from the passive wireless antenna sensor mounted on the structure, wherein the backscattered signal comprises an antenna backscattered signal and a structure backscattered signal, and the antenna backscattered signal is delayed with respect to the structure backscattered signal, such that the structure backscattered signal is received before the antenna backscattered signal; and a digital signal processor that is configured to, using the antenna backscattered signal received from the passive wireless antenna sensor, determine a resonant frequency of the passive wireless antenna sensor based on the antenna backscattered signal and determine the condition of the structure by comparing the determined resonant frequency of the passive wireless antenna sensor to the known resonant frequency of the passive wireless antenna sensor, whereby a change in the resonant frequency of the passive wireless antenna sensor indicates a change in the condition of the structure, including a detected crack in the structure. - View Dependent Claims (15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25)
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Specification