Interdigital transducers on a piezoelectric thin-film for signal compression

Patent metadata

Field	Value
Publication number	US-11451209-B2
Application number	US-201816175439-A
Country	US
Kind code	B2
Filing date	Oct 30, 2018
Priority date	Oct 31, 2017
Publication date	Sep 20, 2022
Grant date	Sep 20, 2022

Abstract

A piezoelectric thin-film suspended above a carrier substrate. An input interdigital transducer (IDT) having first interdigitated electrodes is disposed at different locations along the horizontal axis and on the first side of the piezoelectric thin-film. Each opposing pair of the first interdigitated electrodes is to selectively transduce a particular frequency range of an input electrical signal that varies in frequency over time into an acoustic wave of a laterally vibrating mode based on a pitch between electrodes of the opposing pair. An output IDT that includes second interdigitated electrodes is disposed at different locations along the horizontal axis and on the second side of the piezoelectric thin-film. Each opposing pair of the second interdigitated electrodes is to convert the acoustic wave transduced by the respective opposing pair of the first interdigitated electrodes into a compressed pulse.

First claim

What is claimed is:

1. An apparatus, comprising:
a piezoelectric thin-film suspended above a carrier substrate, the piezoelectric thin-film having a horizontal axis orientated along a length of the piezoelectric thin-film and a center axis orientated along a width of the piezoelectric thin-film, wherein the horizontal axis is perpendicular to the center axis, and wherein the piezoelectric thin-film comprises a first side and a second side with respect to the center axis;
an input interdigital transducer (IDT) comprising first interdigitated electrodes disposed at different locations along the horizontal axis and on the first side of the piezoelectric thin-film, wherein each opposing pair of the first interdigitated electrodes is to selectively transduce a particular frequency range of an input electrical signal, which varies in frequency over time, into an acoustic wave of a laterally vibrating mode based on a pitch between electrodes of the respective opposing pair, and wherein the pitch varies across respective opposing pairs of the first interdigitated electrodes; and
an output IDT comprising second interdigitated electrodes disposed at different locations along the horizontal axis and on the second side of the piezoelectric thin-film, wherein each opposing pair of the second interdigitated electrodes corresponds to a respective opposing pair of the first interdigitated electrodes of equal pitch, and wherein each opposing pair of the second interdigitated electrodes is to convert the acoustic wave transduced by the respective opposing pair of the first interdigitated electrodes into an output signal of a corresponding frequency range, and wherein a plurality of frequency components of the output signals concurrently interfere to form a compressed pulse.

2. The apparatus of claim 1 , wherein a first electrode of a first opposing pair of the first interdigitated electrodes is coupled to an input bus line, wherein a second electrode of the first opposing pair of the first interdigitated electrodes is coupled to an input ground line, wherein a third electrode of a first corresponding opposing pair of the second interdigitated electrodes is coupled to an output bus line, and wherein a fourth electrode of the first corresponding opposing pair of the second interdigitated electrodes is coupled to an output ground line.

3. The apparatus of claim 1 , wherein the acoustic wave travels within the piezoelectric thin-film in at least one of a shear-horizontal (SH0) laterally vibrating mode or a length extensional (S0) laterally vibrating mode, and wherein the piezoelectric thin-film comprises lithium niobate thin-film.

4. The apparatus of claim 1 , wherein the acoustic wave travels within the piezoelectric thin-film in at least one of a shear-horizontal (SH0) laterally vibrating mode, a length extensional (S0) laterally vibrating mode, a first order thickness extensional (S1) mode, or a thickness shear (A1) mode.

5. The apparatus of claim 1 , wherein the piezoelectric thin-film comprises one of lithium niobate thin-film, lithium tantalate thin-film, aluminum nitride thin-film, scandium doped aluminum nitride thin-film, potassium niobate thin-film, or potassium tantalite thin-film.

6. The apparatus of claim 1 , wherein the piezoelectric thin-film comprises one of X-cut, Z-cut, Y-cut, rotated X-cut, rotated Z-cut, or rotated Y-cut piezoelectric thin-film and comprises one of lithium niobate thin-film, lithium tantalate thin-film, potassium niobate thin-film, or potassium tantalite thin-film, or wherein the piezoelectric thin-film comprises c-axis grown aluminum nitride thin-film or c-axis grown scandium doped aluminum nitride thin-film.

7. The apparatus of claim 1 , wherein the input IDT and the output IDT are symmetric about the center axis, wherein a first opposing pair of the first interdigitated electrodes is nearest to the center axis and is located an identical distance from the center axis as a corresponding first opposing pair of the second interdigitated electrodes of first equal pitch, and wherein a second opposing pair of the first interdigitated electrodes is farthest from the center axis and is located an identical distance from the center axis as a corresponding second opposing pair of the second interdigitated electrodes of second equal pitch.

8. The apparatus of claim 1 , wherein the input electrical signal received at the input IDT is an input chirp signal with a bandwidth (B) and a duration (T) that varies in frequency over time, wherein frequency components of the input chirp signal are collected at the output IDT concurrently to form the compressed pulse, and wherein power of the input chirp signal is condensed resulting in an instantaneous power amplification of a time-bandwidth (TB) product to signal.

9. The apparatus of claim 1 , wherein the input electrical signal received at the input IDT comprises discrete frequency components arranged in an order in time, wherein the discrete frequency components of the input electrical signal are collected at the output IDT concurrently to form the compressed pulse having a voltage gain greater than one.

10. The apparatus of claim 1 , wherein acoustic waves of the laterally vibrating mode are to propagate through the piezoelectric thin-film with different delay times that are proportional to distances between each opposing pair of the second interdigitated electrodes and the corresponding opposing pair of the first interdigitated electrodes of equal pitch, and wherein a phase velocity of the acoustic waves of different frequencies is an identical phase velocity.

11. The apparatus of claim 1 , further comprising a cavity disposed between the piezoelectric thin-film and the carrier substrate.

12. The apparatus of claim 1 , wherein the piezoelectric thin-film comprises an electromechanical coupling coefficient greater than 10 percent.

13. The apparatus of claim 1 , wherein the pitches of opposing pairs of the first interdigitated electrodes vary along the horizontal axis.

14. A system comprising:
an antenna to receive an input electrical signal that varies in frequency over time; and
a passive voltage gain device, coupled with the antenna, the passive voltage gain device comprising:
a piezoelectric thin-film suspended above a carrier substrate, the piezoelectric thin-film having a horizontal axis orientated along a length of the piezoelectric thin-film and a center axis orientated along a width of the piezoelectric thin-film, wherein the horizontal axis is perpendicular to the center axis, and wherein the piezoelectric thin-film comprises a first side and a second side with respect to the center axis;
an input interdigital transducer (IDT) comprising first interdigitated electrodes disposed at different locations along the horizontal axis and on the first side of the piezoelectric thin-film, wherein each opposing pair of the first interdigitated electrodes is to selectively transduce a particular frequency range of the input electrical signal into an acoustic wave of a laterally vibrating mode based on a pitch between electrodes of the respective opposing pair, and wherein the pitches of opposing pairs of the first interdigitated electrodes vary along the horizontal axis; and
an output IDT comprising second interdigitated electrodes disposed at different locations along the horizontal axis and on the second side of the piezoelectric thin-film, wherein each opposing pair of the second interdigitated electrodes corresponds to a respective opposing pair of the first interdigitated electrodes of equal pitch, wherein each opposing pair of the second interdigitated electrodes is to convert the acoustic wave trans

Assignees

• Univ Illinois

Inventors

• Gong Songbin
• Lu Ruochen
• Manzaneque Garcia Tomas

Classifications

• H01Q3/22

  varying the orientation in accordance with variation of frequency of radiated wave · CPC title

• H03H2009/155

  using MEMS techniques · CPC title

• H03H9/02228

  Guided bulk acoustic wave devices or Lamb wave devices having interdigital transducers situated in parallel planes on either side of a piezoelectric layer · CPC title

• B06B1/0696

  with a plurality of electrodes on both sides · CPC title

• B06B1/0292

  Electrostatic transducers, e.g. electret-type · CPC title