# US 12,217,890 B2 · Subwavelength antennas, drivers, and systems

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- Number: US 12,217,890 B2
- Document ID: US12217890B2
- Status: Granted
- Kind: B2
- Application number: 17/440,974
- Filed: 2020-03-20
- Published: 2022-05-26
- Granted: 2025-02-04
- Earliest claimed: 2019-03-21
- Assignees: Virginia Commonwealth University
- Applicants: Virginia Commonwealth University
- Inventors: Supriyo Bandyopadhyay
- Web page: https://patentgrep.com/patent/US12217890B2

## CPC

- H01F 10/324: {Exchange coupling of magnetic film pairs via a very thin non-magnetic spacer, e.g. by exchange with conduction electrons of the spacer}
- H01Q 21/061: {Two dimensional planar arrays}
- H01P 3/081: {Microstriplines}
- H01Q 1/364: {using a particular conducting material, e.g. superconductor}
- H03H 9/25: Constructional features of resonators using surface acoustic waves {(devices for manipulating acoustic surface waves in general G10K11/36)}
- H04L 27/12: Modulator circuits; Transmitter circuits
- H04M 1/03: Constructional features of telephone transmitters or receivers, e.g. telephone hand-sets
- H10N 35/00: Magnetostrictive devices (integrated devices or assemblies of multiple devices H10N39/00)
- H10N 50/20: Spin-polarised current-controlled devices (magnetoresistive devices H10N50/10)
- B82Y 25/00: Nanomagnetism, e.g. magnetoimpedance, anisotropic magnetoresistance, giant magnetoresistance or tunneling magnetoresistance
- H01F: MAGNETS; INDUCTANCES; TRANSFORMERS; SELECTION OF MATERIALS FOR THEIR MAGNETIC PROPERTIES
- H01Q: ANTENNAS, i.e. RADIO AERIALS (radiators or antennas for microwave heating H05B6/72)
- H01P: WAVEGUIDES; RESONATORS, LINES, OR OTHER DEVICES OF THE WAVEGUIDE TYPE (operating at optical frequencies G02B)
- H03H: IMPEDANCE NETWORKS, e.g. RESONANT CIRCUITS; RESONATORS (waveguides, resonators, lines or other devices of the waveguide type H01P)
- H04L: TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION (arrangements common to telegraphic and telephonic communication H04M)
- H04M: TELEPHONIC COMMUNICATION (circuits for controlling other apparatus via a telephone cable and not involving telephone switching apparatus G08)
- H10N: ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
- B82Y: SPECIFIC USES OR APPLICATIONS OF NANOSTRUCTURES; MEASUREMENT OR ANALYSIS OF NANOSTRUCTURES; MANUFACTURE OR TREATMENT OF NANOSTRUCTURES

## Abstract

Embodiments generally relate to subwavelength antennas and, more particularly, extreme subwavelength antennas with high radiation efficiency. One embodiment and its derivatives achieve the objective of an extreme subwavelength dual acoustic and electromagnetic antenna by using spin-orbit torque in an array of nanomagnets.

## Claims

### Claim 1

A subwavelength electromagnetic antenna, comprising
a piezoelectric substrate;
an array of magnetostrictive nanomagnets in elastic contact with the piezoelectric substrate; and
a driver configured to actuate the array by causing magnetization oscillations in the magnetostrictive nanomagnets using surface acoustic waves (SAWs) launched in the piezoelectric substrate, wherein the driver is configured to change SAW frequencies to cause the array to radiate electromagnetic waves at multiple frequencies that match the SAW frequencies up to a predetermined limit,
wherein the array of magnetostrictive nanomagnets is configured to (i) convert phonons of the SAWs to magnons via phonon-magnon coupling and (ii) convert the magnons to photons of the electromagnetic waves via magnon-photon coupling.

### Claim 2 (depends on 1)

The subwavelength electromagnetic antenna of claim 1, wherein the driver is configured to launch the surface acoustic wave (SAW) in the substrate with an alternating electrical voltage.

### Claim 3 (depends on 1)

The subwavelength electromagnetic antenna of claim 1, wherein the array of nanomagnets define an emitting area (A) and, when driven, radiate an electromagnetic wave of a wavelength (λ), wherein the ratio A/λ2 is on the order of 10−9.

### Claim 4 (depends on 1)

The subwavelength electromagnetic antenna of claim 1, wherein the magnetostrictive nanomagnets are each 100-500 nm in length and/or 100-500 nm in width.

### Claim 5 (depends on 1)

The subwavelength electromagnetic antenna of claim 1, wherein a greater number of magnetostrictive nanomagnets in the array corresponds with a greater emitted signal strength.