Transmit-receive delay element apparatus, method, and applications
AssigneeCornell University
InventorsAmit Lal, Mamdouh Abdelmejeed, Justin Kuo
Life of this patent
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Abstract
A CMOS compatible GHz ultrasonic pulse/echo transmit-receive ultrasonic delay element demonstrating less than <6 ppm stability over time and having a zero-temperature coefficient of delay at two temperatures. The delay element includes one or more CMOS compatible piezoelectric transducers requiring no release step, which transmit and/or receive a GHz-ultrasonic wave packet. The bulk substrate exhibits low loss for the GHz-ultrasonic wave packet transmitted through the substrate and uses the phenomenon of diffraction to retrieve multiple reflections.
Claims19
An integrated delay apparatus, comprising:
- a substrate;
- a piezoelectric transducer integrally disposed on or in the substrate,
- wherein the piezoelectric transducer is adapted to generate an ultrasonic wave packet having a temporal width from 0.5 to 100 nanoseconds,
- further wherein the substrate has a thickness, h, that is greater than a spatial width of the ultrasonic wave packet corresponding to the temporal width,
- further wherein an interface between a bottom surface of the substrate and a medium immediately adjacent the bottom surface of the substrate exhibits an impedance mismatch whereby the bottom surface of the substrate is a reflective surface for the ultrasonic wave packet;
- and
- further wherein the integrated delay apparatus is characterized by a delay time, τ, where τ≥2h/vs, where vs is a speed of sound in the substrate.
An integrated delay apparatus, comprising
- a substrate;
- a transmitting piezoelectric transducer integrally disposed on or in the substrate;
- a receiving piezoelectric transducer integrally disposed on or in the substrate;
- wherein the transmitting piezoelectric transducer is adapted to generate an ultrasonic was pocket having a temporal width form 0.5 to 100 nanoseconds;
- further wherein the substrate has a thickness, h, that is greater than a spatial width of the ultrasonic wave packet corresponding to the temporal width;
- further wherein an interface between a bottom surface of the substrate and a medium immediately adjacent the bottom surface of the substrate exhibits an impedance mismatch whereby the bottom surface of the substrate is a reflective surface for the ultrasonic wave packet;
- and
- further wherein the transmitting piezoelectric transducer has a largest transverse surface dimension between 0.5 to 20λ, where λ is a longitudinal wavelength of the ultrasonic wave packet with a carrier frequency, f, where f is between 0.5 to 10 GHz.
A method for generating a stable delay time, comprising:
- generating an ultrasonic wave packet having a temporal width from 0.5 to 100 ns with a carrier frequency, f, where f is between 0.5 to 10 GHz;
- transmitting, using a CMOS-integrated piezoelectric transmit transducer, the ultrasonic wave packet through a bulk substrate;
- reflecting the transmitted ultrasonic wave packet from a top and/or a bottom surface of the bulk substrate;
- and
- detecting, using a CMOS-integrated piezoelectric transmit transducer, the reflected ultrasonic wave packet;
- wherein the CMOS-integrated piezoelectric receive transducer is laterally located at a distance from the CMOS-integrated piezoelectric transmit transducer such that the delay is temperature stabilized at adjustable temperatures.
An integrated delay apparatus, comprising:
- a substrate;
- a piezoelectric transducer integrally disposed on or in the substrate;
- wherein the piezoelectric transducer is adapted to generate an ultrasonic wave packet having a temporal width from 0.5 to 100 nanoseconds;
- further wherein the substrate has a thickness, h, that is greater than a spatial width of the ultrasonic wave packet corresponding to the temporal width;
- further wherein an interface between a bottom surface of the substrate and a medium immediately adjacent the bottom surface of the substrate exhibits an impedance mismatch whereby the bottom surface of the substrate is a reflective surface for the ultrasonic wave packet;
- and
- further wherein the integrated delay apparatus is characterized by an Allan deviation of 0.87 ps (<6 ppm).
Dependencies are inferred from the claim text.