Frequency and phase controlled transducers and sensing
View Patent ↗Localized heating can use a fixed-frequency planar transmission line resonators arranged along a main-line, selected by tuning an electromagnetic input signal frequency applied to the main line for depositing heat in an adjacent active substrate. More generally, adjusting input signal frequency can be used to selectively address and energize an electromagnetic-to-heat, an electromagnetic-to-vibration, or other transducer to controllably direct energy toward a desired transducer load. Resonators or other electromagnetically energized transducers can be arranged to electromagnetically interfere, such that specifying or adjusting a relative phase of applied electrical signals can be used to specify or adjust the energy directed toward a desired transducer load. Temperature sensing can characterize a material in a target region near the transducer. A cold-hot-cold temperature profile can better manage temperature and avoid overheating a dielectric material such as the active substrate material.
1. A transmission line based control device for an integrated transducer, the device comprising:
a substrate providing or coupled to the transducer; and
a planar resonator configured to receive an AC electromagnetic input signal, wherein the resonator is constructed of a planar arrangement of electrically conductive traces that are configured to resonate at its characteristic AC electromagnetic input signal frequency using an AC electromagnetic input signal that is received to frequency-select, without requiring a switch, and to energize the transducer at a first energy level.
2. The device of claim 1 , wherein the resonator is configured to receive the AC electromagnetic input signal directly.
3. The device of claim 2 , wherein the resonator is capacitively coupled to at least one of a ground conductor or a ground plane.
4. The device of claim 1 , comprising an electrically conductive connection between the resonator and a main line.
5. The device of claim 1 , comprising a plurality of resonators, respectively co-located with corresponding transducers, at different locations along a main line, wherein the substrate comprises a dielectric substrate.
6. The device of claim 5 , wherein the substrate comprises a lossy dielectric substrate.
7. The device of claim 5 , wherein:
an individual first one of the resonators is configured to resonate at a first characteristic AC electromagnetic input signal frequency to generate transduced energy at the co-located first one of the transducers; and
an individual second one of the resonators is configured to be off-resonance at the first characteristic AC electromagnetic input signal frequency, to generate less transduced energy at the co-located second one of the transducers than is generated in the first one of the transducers at the first characteristic AC electromagnetic input signal frequency.
8. The device of claim 1 wherein the resonator comprises a first resonator and a second resonator, arranged in a cascade with the first resonator.
9. The device of claim 1 , comprising first and second resonators that are configured to be independently addressed using different characteristic AC electromagnetic input signal frequencies.
10. The device of claim 1 , comprising a plurality of resonators, wherein respective ones of the resonators are arranged to provide sufficient frequency-domain spacing between corresponding characteristic AC electromagnetic input signal frequencies of corresponding resonators such that ones or groups of the resonators are selectively addressable by applying a variable frequency of the received AC electromagnetic input signal.
11. The device of claim 1 , comprising interfering first and second resonators that are configured to electromagnetically interfere with each other to permit phase control of the interfering first and second resonators by specifying or varying a phase of a first electrical signal delivered to the first resonator relative to a phase of a second electrical signal delivered to the second resonator.
12. The device of claim 11 , including or coupled to control circuitry configured for selectively addressing the first and second resonators by selecting or varying a frequency of the first electrical signal delivered to the first resonator and a frequency of the second electrical signal delivered to the second resonator, the control circuitry further configured for specifying or varying the phase of a first electrical signal delivered to the first resonator relative to the phase of the second electrical signal delivered to the second resonator.
13. The device of claim 11 , wherein the substrate is a lossy dielectric active substrate including or coupled to the first and second resonators, and comprising control circuitry is configured to control heat generated in the lossy dielectric active substrate including by specifying or varying the phase of a first electrical signal delivered to the first resonator relative to the phase of the second electrical signal delivered to the second resonator.
14. The device of claim 1 , comprising:
one or more temperature sensors, configured to measure temperature at a corresponding one or more measurement locations corresponding to one or more respective resonator-activated heating locations of the substrate for communication to a signal processor circuit that is configured to process one or more signals representing measured temperature to compute an indication of a material characteristic of a target region near the one or more measurement locations based on the measured temperature.
15. A method of using a transmission line based control device to control a transducer, the method comprising:
receiving an AC electromagnetic input signal at a planar resonator via a transmission line, wherein the planar resonator is constructed of a planar arrangement of electrically conductive traces that are configured to resonate at a characteristic AC electromagnetic signal frequency; and
using the received AC electromagnetic input signal at a first frequency to resonate the resonator at its characteristic AC electromagnetic input signal frequency to frequency-select, without requiring a switch, and to energize a transducer at a first energy level.
16. The method of claim 15 , further comprising:
using the received AC electromagnetic input signal at a second frequency to put the planar resonator off-resonance at a frequency different from the characteristic AC electromagnetic input signal frequency to energize the transducer at a second energy level that is less than the first energy level.
17. The method of claim 15 , wherein the energizing the transducer transduces the AC electromagnetic input signal into a different energy form.
18. The method of claim 15 , comprising:
receiving the AC electromagnetic input signal at a first resonator, at its first characteristic AC electromagnetic input signal frequency, to activate a first transducer co-located with the first resonator; and
receiving the AC electromagnetic input signal to be off-resonance at a second resonator, at the first characteristic AC electromagnetic input signal frequency, to activate a second transducer co-located with the second resonator at a level less than that of the first transducer.
19. The method of claim 15 , comprising capacitively coupling the resonator to at least one of a ground line or a ground plane.
20. The method of claim 15 , further comprising independently addressing first and second resonators having different characteristic AC electromagnetic input signal frequencies by receiving a variable frequency of the received AC electromagnetic input signal.
21. The method of claim 15 , further comprising using phase control of electromagnetically interfering first and second resonators by specifying or varying a phase of a first electrical signal delivered to the first resonator relative to a phase of the second electrical signal delivered to the second resonator.
22. The method of claim 21 , wherein a dielectric substrate provides or is coupled to the first and second resonators, and comprising:
controlling heat generated in the dielectric substrate including by varying the phase of a first electrical signal delivered to the first resonator relative to the phase of the second electrical signal delivered to the second resonator.
23. The method of claim 15 , further comprising:
selectively addressing first and second resonators by selecting or varying a frequency of the first electrical signal delivered to the first resonator and a frequency of the second electrical signal delivered to the second resonator; and
specifying or varying a phase of a first electrical signal delivered to the first resonator relative to the phase of the second electrical signal delivered to the second resonator.