Bulk acoustic wave mediated multiferroic antennas

Patent metadata

Field	Value
Publication number	US-10218072-B2
Application number	US-201615171956-A
Country	US
Kind code	B2
Filing date	Jun 2, 2016
Priority date	Jun 8, 2015
Publication date	Feb 26, 2019
Grant date	Feb 26, 2019

Abstract

An antenna apparatus utilizing bulk acoustic wave (BAW) resonances to transfer dynamic strain across multiple layers, which include piezoelectric layers coupled to magnetostrictive material layers. In at least one embodiment, a piezoelectric layer is coupled to a magnetostrictive layer to which another layer having similar acoustic properties as the piezoelectric layer is coupled as an inertial buffer. These multiple layers comprise a strain media to provide a vertical multiferroic coupling which couples electric field, magnetic field, and mechanical fields. Electrodes are coupled to excite one of the piezoelectric layers for injecting acoustic waves into the structure from which electromagnetic radiation is generated out of the plane.

First claim

What is claimed is:

1. A bulk acoustic wave mediated multiferroic antenna apparatus, comprising:
(a) a substrate layer;
(b) multiple layers within a multiple layer strain media, comprising:
(i) at least one piezoelectric material layer having a first set of acoustic properties;
(ii) at least one magnetostrictive material layer coupled to a first side of said piezoelectric material layer;
(iii) a structure layer extending from a second side of said piezoelectric material layer to said substrate layer and which is shaped to create a gap or cavity between said piezoelectric material layer and said substrate to mechanically decouple said multiple layer strain media from said substrate;

(c) wherein said at least one piezoelectric material layer and said at least one magnetostrictive material layer are disposed in an out of plane dimension in relation to the emitted electromagnetic radiation from said apparatus;
(d) wherein said at least one piezoelectric material layer and said at least one magnetostrictive material layer are coupled together into the multiple layer strain media to provide a vertical multiferroic coupling which couples electric field, magnetic field, and mechanical field; and
(e) at least two electrodes coupled to one or more layers of said at least one piezoelectric material layer for exciting that layer, or layers, in response to receiving radio-frequency electric field signals to inject acoustic waves into the multiple layer strain media, from which electromagnetic radiation is generated out of the plane on the exterior of said apparatus;
(f) wherein injection of acoustic waves into the multiple layer strain media induces a resonance mode in the entire apparatus which creates substantial strain in said at least one magnetostrictive material layer, which results in oscillating magnetization which produces a radiating electromagnetic RF wave which is emitted from said apparatus which is operating as an antenna.

2. The apparatus as recited in claim 1 , wherein said multiple layer strain media further comprises at least one acoustic buffer layer configured as an acoustic or inertial damper coupled to said magnetostrictive material layer and having acoustic properties for receiving acoustic waves transmitted from said at least one piezoelectric material layer and through said at least one magnetostrictive material layer.

3. The apparatus as recited in claim 1 , wherein said apparatus operates in response to using a coupled acoustic resonant mode, driven by said at least two electrodes exciting said at least one piezoelectric material layer which subsequently drives electromagnetics through strain coupling in which geometric characteristics determine the excited mode, to excite magnetic fluctuation through strain coupling.

4. The apparatus as recited in claim 1 , wherein said at least one piezoelectric material layer comprises a material having a sufficient electric polarization to strain characteristic, wherein upon sufficient electrically excitation it causes injection acoustic waves into said multiple layer strain media.

5. The apparatus as recited in claim 1 , wherein said at least one piezoelectric material layer comprises an electroelastic material having sufficient magnetization-to-strain characteristics to excite said multiple layer strain media into acoustic oscillation.

6. The apparatus as recited in claim 5 , wherein said electroelastic material is selected from a group of electroelastic materials consisting of Alumina Nitride (AlN), Lithium Niobate, Lead Zirconate Titanate (PZT), Lead Magnesium Niobate Titanate (PMN-PT), Lead Magnesium Niobate (PMN), and Quartz.

7. The apparatus as recited in claim 1 , wherein said at least one magnetostrictive material layer comprises a magnetoelastic material having magnetization-to-strain characteristics which create said oscillating magnetization in response to strain induced by excitation from said at least one piezoelectric or electroelastic material.

8. The apparatus as recited in claim 7 , wherein said at least one piezoelectric material layer comprises Alumina Nitride (AlN).

9. The apparatus as recited in claim 7 , wherein said at least one magnetostrictive material layer is selected from a group of magnetoelastic material consisting of Permalloy, Terfenol-D, YiG, CoFeB, FeGaB, NiMgZnO3, and Metglas.

10. The apparatus as recited in claim 1 , wherein said at least one piezoelectric material layer comprises multiple piezoelectric material layers, and said at least one magnetostrictive material layer comprises multiple magnetostrictive material layers, and wherein said multiple piezoelectric material layers and said multiple magnetostrictive material layers are interleaved.

11. The apparatus as recited in claim 1 , wherein said RF wave is emitted from an external layer comprising at least one acoustic buffer layer.

12. The apparatus as recited in claim 1 , wherein said gap or cavity comprises air or a material for mechanically decoupling said multiple layer strain media from said substrate.

13. The apparatus as recited in claim 1 , wherein said structure for retaining said multilayer structure comprises a dielectric material.

14. The apparatus as recited in claim 13 , wherein said dielectric material comprises silicon nitride.

15. The apparatus as recited in claim 1 , wherein thickness for each layer within said multiple layer strain media are between 200 nanometers and 2 millimeters.

16. The apparatus as recited in claim 1 , wherein said vertical multiferroic coupling is fabricated in the out-of-plane dimension, whereby resonant frequencies of said apparatus is independent of horizontal dimensions of said vertical multiferroic coupling.

17. A bulk acoustic wave mediated multiferroic antenna apparatus, comprising:
(a) a substrate layer;
(b) multiple layers within a multiple layer strain media, comprising:
(i) at least one piezoelectric material layer having a first set of acoustic properties;
(ii) at least one magnetostrictive material layer coupled to a first side of each of said at least one piezoelectric material layer; and
(iii) at least one acoustic buffer layer coupled to a magnetostrictive material layer within said at least one magnetostrictive layer, which is farthest from said substrate, said acoustic buffer layer configured as an acoustic or inertial damper having acoustic properties for receiving acoustic waves transmitted from said at least one piezoelectric material layer, and through said at least one magnetostrictive material layer;
(iv) a structure layer extending from at least one piezoelectric material layer to said substrate layer and which is shaped to create a gap or cavity between said piezoelectric material layer and said substrate to mechanically decouple said multiple layer strain media from said substrate;

(b) wherein said at least one piezoelectric material layer, said at least one magnetostrictive material layer, and said at least one acoustic buffer layer are disposed in an out of plane dimension in relation to the emitted electromagnetic radiation from said apparatus;
(c) wherein said at least one piezoelectric material layer, said at least one magnetostrictive material layer, and said at least one acoustic buffer layer are coupled together into the multiple layer strain media to provide a vertical multiferroic coupling which couples electric field, magnetic field, and mechanical field; and
(d) at least two electrodes coupled to one or more layers of said at least one piezoelectric material layer for exciting that layer, or layers, in response to receiving radio-frequency electr

Assignees

• Univ California

Inventors

• Wang Yuanxun Ethan
• Carman Gregory P
• Candler Robert Norris
• KELLER Scott

Classifications

• H01Q3/44

  varying the electric or magnetic characteristics of reflecting, refracting, or diffracting devices associated with the radiating element · CPC title

• H03H9/22

  Constructional features of resonators consisting of magnetostrictive material · CPC title

• H01Q7/06 Primary

  with core of ferromagnetic material (H01Q7/02 takes precedence) · CPC title

• H01Q1/52 Primary

  Means for reducing coupling between antennas; Means for reducing coupling between an antenna and another structure (absorbing means H01Q17/00) · CPC title

• H03H9/173

  Air-gaps · CPC title