# US 11,443,124 B2 · Reading of an electromagnetic resonant structure by a separated transmitter and receiver > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 11,443,124 B2 - Document ID: US11443124B2 - Status: Granted - Kind: B2 - Application number: 16/952,755 - Filed: 2020-11-19 - Published: 2022-05-19 - Granted: 2022-09-13 - Earliest claimed: 2020-11-19 - Assignees: Palo Alto Research Center Incorporated - Applicants: Palo Alto Research Center Incorporated - Inventors: David Eric Schwartz; Farzad Inanlou; Shabnam Ladan; Dogan Timucin - Web page: https://patentgrep.com/patent/US11443124B2 ## CPC - G06K 7/10148: {the step consisting of dynamically tuning the resonant circuit of the interrogation device that is emitting the interrogation signal, e.g. for impedance matching inside of the interrogation device (for tuning related to loop aerials in general H01Q7/00)} - G06K 19/0672: {with resonating marks} - G06K 7/10009: {sensing by radiation using wavelengths larger than 0.1 mm, e.g. radio-waves or microwaves} - G06K: GRAPHICAL DATA READING (image or video recognition or understanding G06V); PRESENTATION OF DATA; RECORD CARRIERS; HANDLING RECORD CARRIERS ## Abstract A resonant structure includes a conductive surface layer on a dielectric layer that produces an enhanced or reduced backscattered radiation in one or more resonant frequency bands when illuminated with electromagnetic energy. A transmitter illuminates the resonant structure with the electromagnetic energy at a first angle relative to the normal of the conductive surface. A receiver is operable to detect the enhanced or reduced backscattered radiation at the resonant frequency bands at a second angle relative to the normal of the conductive surface. The second angle is different from the first angle by at least five degrees. A processor coupled to the receiver and is operable to detect data encoded in one or both of a frequency response and a polarization response of the resonant structure based on the detected enhanced or reduced backscattered radiation. ## Claims ### Claim 1 A system comprising: a resonant structure comprising a conductive surface layer on a dielectric layer that produces an enhanced or reduced backscattered radiation in one or more resonant frequency bands when illuminated with electromagnetic energy; a transmitter illuminating the resonant structure with the electromagnetic energy at a first angle relative to a normal of the conductive surface layer; a receiver operable to detect the enhanced or reduced backscattered radiation at the resonant frequency bands at a second angle relative to the normal of the conductive surface layer, the second angle different from the first angle by at least five degrees; and a processor coupled to the receiver and operable to detect data encoded in one or both of a frequency response and a polarization response of the resonant structure based on the detected enhanced or reduced backscattered radiation, the data being encoded within the resonant structure, wherein the processor is coupled to the transmitter and further operable to synchronize the illumination with the backscattered radiation through an optical signal transmitted to the transmitter and the receiver, the optical signal combined with a detected backscattering radiation signal to synchronize the transmitter and the receiver via deramping. ### Claim 2 (depends on 1) The system of claim 1, wherein the first and second angles are non-zero and oblique relative to the normal of the conductive surface layer. ### Claim 3 (depends on 2) The system of claim 2, wherein the first and second angles are at a same angular separation in opposite directions from the normal of the conductive surface layer. ### Claim 4 (depends on 1) The system of claim 1, wherein the second angle is zero. ### Claim 5 (depends on 1) The system of claim 1, wherein the system includes an actuator to induce relative motion between the resonant structure and one or both of the transmitter and the receiver while the resonant structure is illuminated and the backscattered radiation is detected, the processor further operable to determine one of a synthetic aperture radar (SAR) and inverse SAR image based on the detection of the backscattered radiation. ### Claim 6 (depends on 1) The system of claim 1, wherein the frequency band of the resonant structure varies with an environment of the resonant structure, the processor further operable to measure the environment of the resonant structure based on the detected backscattered radiation. ### Claim 7 (depends on 6) The system of claim 6, wherein the environment comprises at least one of humidity, temperature, vibration, concentration of a specific gas, and optical illumination. ### Claim 8 (depends on 1) The system of claim 1, wherein the processor is further operable to detect the data based on two or more polarization responses of the resonant structure. ### Claim 9 (depends on 1) The system of claim 1, wherein the electromagnetic energy illuminates the resonant structure at a plurality of frequencies within a band that includes the resonant frequencies of the structure. ### Claim 10 (depends on 1) The system of claim 1, wherein the resonant frequency bands are between 10 and 100 GHz. ### Claim 11 A method, comprising: illuminating a resonant structure with electromagnetic energy via a transmitter that is at a first angle relative to a normal of a conductive surface layer of the resonant structure, the conductive surface layer formed on a dielectric layer and producing backscattered radiation at a resonant frequency band in response to the illumination; detecting, via a receiver, the backscattered radiation at the resonant frequency band at a second angle relative to the normal of the conductive surface layer, the second angle different from the first angle by at least five degrees; detecting data encoded in one or both of a frequency response and a polarization response of the resonant structure based on an enhancement or reduction of the detected backscattered radiation, the data being encoded within the resonant structure; and synchronizing the illumination with the backscattered radiation through an optical signal transmitted to the transmitter and the receiver, the optical signal combined with a detected backscattering radiation signal to synchronize the transmitter and the receiver via deramping. ### Claim 12 (depends on 11) The method of claim 11, wherein the first and second angles are equal in magnitude, non-zero and oblique relative to the normal of the conductive surface layer. ### Claim 13 (depends on 11) The method of claim 11, wherein the second angle is zero. ### Claim 14 (depends on 11) The method of claim 11, further comprising: inducing relative motion between the resonant structure and one or both of the transmitter and the receiver while the resonant structure is illuminated and the backscattered radiation is detected; and determining one of a synthetic aperture radar (SAR) and inverse SAR image based on the detected backscattered radiation. ### Claim 15 (depends on 11) The method of claim 11, wherein the frequency band of the resonant structure varies with an environment of the resonant structure, the method further comprising measuring the environment of the resonant structure based on the detected backscattered radiation. ### Claim 16 (depends on 11) The method of claim 11, further comprising detecting the data based on two or more polarization responses of the resonant structure. ### Claim 17 (depends on 11) The method of claim 11, wherein the electromagnetic energy illuminates the resonant structure at a plurality of frequencies within a band that includes the resonant frequencies of the structure.