# US 10,374,669 B2 · Tunable medium linear coder

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- Number: US 10,374,669 B2
- Document ID: US10374669B2
- Status: Granted
- Kind: B2
- Application number: 15/253,606
- Filed: 2016-08-31
- Published: 2018-03-01
- Granted: 2019-08-06
- Earliest claimed: 2016-08-31
- Assignees: Elwha LLC
- Applicants: Elwha LLC
- Inventors: Clarence T. Tegreene; Yaroslav A. Urzhumov
- Web page: https://patentgrep.com/patent/US10374669B2

## CPC

- H04B 7/0456: Selection of precoding matrices or codebooks, e.g. using matrices antenna weighting
- H01Q 3/46: Active lenses or reflecting arrays
- H01Q 15/0066: {said selective devices being reconfigurable, tunable or controllable, e.g. using switches}
- H01Q 15/02: Refracting or diffracting devices, e.g. lens, prism
- H01Q 19/06: using refracting or diffracting devices, e.g. lens {(radome H01Q1/42)}
- H04B 7/0413: MIMO systems
- H04B: TRANSMISSION
- H01Q: ANTENNAS, i.e. RADIO AERIALS (radiators or antennas for microwave heating H05B6/72)

## Abstract

Disclosed are antenna systems and related methods. An antenna system includes a plurality of near-end electromagnetic (EM) radiating elements, a tunable medium, and control circuitry. The tunable medium is positioned relative to the plurality of near-end EM radiating elements and a plurality of far-end EM radiating elements to scatter EM radiation transmitted between the plurality of near-end EM radiating elements and the plurality of far-end EM radiating elements. The control circuitry includes a controller operably coupled to the tunable medium. A method includes modifying EM properties of the tunable medium to modify the EM radiation transmitted between the plurality of near-end EM radiating elements and the plurality of far-end EM radiating elements.

## Claims

### Claim 1

An antenna system, comprising:
a plurality of near-end electromagnetic (EM) radiating elements;
a tunable medium positioned relative to the plurality of near-end EM radiating elements and a plurality of far-end EM radiating elements to scatter EM radiation transmitted between the plurality of near-end EM radiating elements and the plurality of far-end EM radiating elements; and
control circuitry comprising a controller operably coupled to the tunable medium and programmed to modify EM properties of the tunable medium to operate as a linear coder between the plurality of near-end EM radiating elements and the plurality of far-end EM radiating elements based on which of the plurality of near-end EM radiating elements and the plurality of far-end EM radiating elements is a source of the EM radiation transmitted between the plurality of near-end EM radiating elements and the plurality of far-end EM radiating elements to modify the EM radiation transmitted between the plurality of near-end EM radiating elements and the plurality of far-end EM radiating elements.

### Claim 2 (depends on 1)

The antenna system of claim 1, wherein the control circuitry further comprises signal generation circuitry operably coupled to the plurality of near-end EM radiating elements and configured to deliver EM signals including a plurality of different data streams to the plurality of near-end EM radiating elements for transmission to the plurality of far-end EM radiating elements.

### Claim 3 (depends on 2)

The antenna system of claim 2, wherein the tunable medium comprises a tunable metamaterial comprising a plurality of tunable EM scattering elements.

### Claim 4 (depends on 3)

The antenna system of claim 3, wherein the plurality of tunable EM scattering elements comprises a plurality of tunable capacitive elements.

### Claim 5 (depends on 3)

The antenna system of claim 3, wherein the plurality of tunable EM scattering elements comprises a plurality of variable resistive elements.

### Claim 6 (depends on 3)

The antenna system of claim 3, wherein the plurality of tunable EM scattering elements comprises a plurality of variable inductance elements.

### Claim 7 (depends on 2)

The antenna system of claim 2, wherein the controller is programmed to dynamically tune the tunable medium to function as a linear beamforming precoder.

### Claim 8 (depends on 2)

The antenna system of claim 2, wherein the controller is programmed to dynamically tune the tunable medium to function as a linear spatial-diversity precoder.

### Claim 9 (depends on 2)

The antenna system of claim 2, wherein the controller is programmed to dynamically tune the tunable medium to function as a linear spatial multiplexing precoder.

### Claim 10 (depends on 9)

The antenna system of claim 9, wherein the controller is programmed to dynamically determine a channel matrix of channels between the plurality of near-end EM radiating elements and the plurality of far-end EM radiating elements, and dynamically tune the tunable medium as a function of the determined channel matrix.

### Claim 11 (depends on 10)

The antenna system of claim 10, wherein the controller is programmed to determine values of control parameters of the tunable medium.

### Claim 12 (depends on 11)

The antenna system of claim 11, wherein the controller is programmed to determine the values of the control parameters of the tunable medium by solving an inverse scattering problem, wherein the inverse scattering problem is postulated as an equality between a determined extended channel matrix and a desired extended channel matrix.

### Claim 13 (depends on 11)

The antenna system of claim 11, wherein the controller is programmed to determine the values of the control parameters of the tunable medium by determining a minimization of a matrix norm of a difference between a determined extended channel matrix and a desired extended channel matrix.

### Claim 14 (depends on 11)

The antenna system of claim 11, wherein the controller is programmed to determine the values of the control parameters of the tunable medium by determining a minimization of a sum of squared differences between at least a portion of values from a determined extended channel matrix and corresponding values of a desired extended channel matrix.

### Claim 15 (depends on 11)

The antenna system of claim 11, wherein the controller is programmed to determine the values of the control parameters of the tunable medium by determining a minimization of a sum of squared differences between at least a portion of values from a determined extended channel matrix and corresponding values of a desired extended channel matrix, plus a weighted sum of frequency dispersion magnitudes of the portion of values.

### Claim 16 (depends on 10)

The antenna system of claim 10, wherein the controller is programmed such that a precoder matrix of the tunable medium is at least approximately equal to U†, where UΣV† is a singular value decomposition of the determined channel matrix, and U† is the conjugate transpose of unitary matrix U.

### Claim 17 (depends on 10)

The antenna system of claim 10, wherein the controller is programmed such that a precoder matrix of the tunable medium is at least approximately equal to a left pseudo-inverse of the determined channel matrix.

### Claim 18 (depends on 10)

The antenna system of claim 10, wherein the controller is programmed such that a precoder matrix of the tunable medium multiplied by the determined channel matrix produces a matrix that is approximately equal to a diagonal matrix.

### Claim 19 (depends on 10)

The antenna system of claim 10, wherein the controller is programmed such that a precoder matrix of the tunable medium multiplied by the determined channel matrix produces a matrix having off-diagonal elements, wherein a magnitude of each of the off-diagonal elements is less than or equal to a predetermined threshold value.

### Claim 20 (depends on 10)

The antenna system of claim 10, wherein the controller is programmed such that a matrix product between a precoder matrix of the tunable medium and the determined channel matrix multiplied by a decoder matrix of a far-end decoder is approximately equal to a diagonal matrix.

### Claim 21

A method of operating an antenna system, the method comprising:
operating a plurality of near-end electromagnetic (EM) radiating elements; scattering EM radiation transmitted between the plurality of near-end EM radiating elements and a plurality of far-end EM radiating elements with a tunable medium; and
modifying EM properties of the tunable medium to operate as a linear coder between the plurality of near-end EM radiating elements and the plurality of far-end EM radiating elements based on which of the plurality of near-end EM radiating elements and the plurality of far-end EM radiating elements is a source of the EM radiation transmitted between the plurality of near-end EM radiating elements and the plurality of far-end EM radiating elements to modify the EM radiation transmitted between the plurality of near-end EM radiating elements and the plurality of far-end EM radiating elements.

### Claim 22 (depends on 21)

The method of claim 21, wherein modifying EM properties of the tunable medium comprises dynamically modifying the EM properties of the tunable medium during operation of the antenna system.

### Claim 23 (depends on 21)

The method of claim 21, wherein modifying EM properties of the tunable medium comprises pre-selecting a state of the tunable medium and holding the tunable medium in the selected state during operation of the antenna system.

### Claim 24 (depends on 21)

The method of claim 21, further comprising delivering EM signals including a plurality of different data streams to the plurality of near-end EM radiating elements for transmission to the plurality of far-end EM radiating elements.

### Claim 25 (depends on 24)

The method of claim 24, wherein delivering EM signals includes delivering the EM signals to the plurality of near-end EM radiating elements for transmission to the plurality of far-end EM radiating elements distributed between at least two physically separate devices.

### Claim 26 (depends on 24)

The method of claim 24, wherein delivering EM signals includes delivering EM signals including a number of different data streams that is equal to a number of the plurality of far-end EM radiating elements, each of the plurality of far-end EM radiating elements receiving only one of the plurality of data streams.

### Claim 27 (depends on 24)

The method of claim 24, wherein delivering EM signals includes delivering EM signals including a number of different data streams that is less than a number of the plurality of far-end EM radiating elements.

### Claim 28 (depends on 24)

The method of claim 24, wherein delivering EM signals includes delivering EM signals including a number of different data streams that is equal to a number of the plurality of near-end EM radiating elements.

### Claim 29 (depends on 24)

The method of claim 24, wherein delivering EM signals includes delivering EM signals including a number of different data streams that is less than a number of the plurality of near-end EM radiating elements.

### Claim 30 (depends on 24)

The method of claim 24, wherein scattering EM radiation with a tunable medium comprises scattering the EM radiation with a tunable metamaterial comprising a plurality of tunable EM scattering elements.

### Claim 31 (depends on 30)

The method of claim 30, wherein scattering the EM radiation with a tunable metamaterial comprising a plurality of tunable EM scattering elements comprises scattering the EM radiation with at least one tunable-impedance two-port lumped circuit element.

### Claim 32 (depends on 24)

The method of claim 24, wherein scattering EM radiation with a tunable medium comprises scattering the EM radiation with a tunable medium that is tunable with a number of degrees of freedom that is greater than or equal to a number of independent elements of a channel matrix of channels between the plurality of near-end EM radiating elements and the plurality of far-end EM radiating elements.

### Claim 33 (depends on 24)

The method of claim 24, wherein scattering EM radiation transmitted between the plurality of near-end EM radiating elements and a plurality of far-end EM radiating elements comprises scattering the EM radiation at least substantially in a direction of a specular reflection relative to a surface of a body carrying the plurality of near-end EM radiating elements.

### Claim 34 (depends on 24)

The method of claim 24, wherein scattering EM radiation transmitted between the plurality of near-end EM radiating elements and a plurality of far-end EM radiating elements comprises scattering the EM radiation at least substantially in a direction towards the plurality of far-end EM radiating elements.

### Claim 35 (depends on 24)

The method of claim 24, wherein operating a plurality of near-end EM radiating elements comprises operating the plurality of near-end EM radiating elements with the tunable medium at least partially surrounding at least a portion of the plurality of near-end EM radiating elements.

### Claim 36 (depends on 35)

The method of claim 35, wherein operating the plurality of near-end EM radiating elements with the tunable medium at least partially surrounding at least a portion of the plurality of near-end EM radiating elements comprises operating the plurality of near-end radiating elements inside of a tunable radome comprising the tunable medium.

### Claim 37 (depends on 24)

The method of claim 24, further comprising dynamically tuning the tunable medium to function as a linear beamforming precoder.

### Claim 38 (depends on 24)

The method of claim 24, further comprising dynamically tuning the tunable medium to function as a linear spatial-diversity precoder.

### Claim 39 (depends on 24)

The method of claim 24, further comprising dynamically tuning the tunable medium to function as a linear spatial multiplexing precoder.