Liquid-crystal reconfigurable multi-beam phased array

• US 10,211,532 B2
• Filed: 08/29/2017
• Issued: 02/19/2019
• Est. Priority Date: 05/01/2017
• Status: Active Grant

• Current Assignee: Huawei Technologies Co., Ltd. (Huawei Investment & Holding Co., Ltd.)
• Original Assignee: Huawei Technologies Co., Ltd. (Huawei Investment & Holding Co., Ltd.)
• Inventors: Foo, Senglee
• Primary Examiner(s): Williams, Howard
• Application Number:
  US15/689,817
• Publication Number:
  US 20180316090A1
• Time in Patent Office: 539 Days
• Field of Search: 343909, 343911, 342368, 342371
• CPC Class Codes: H01Q 1/523 between antennas of an array
• CPC Class Codes: H01Q 15/002 said selective devices being reconfigurable or tunable, e.g. using switches or diodes
• CPC Class Codes: H01Q 15/0066 said selective devices being reconfigurable, tunable or controllable, e.g. using switches
• CPC Class Codes: H01Q 19/06 using refracting or diffracting devices, e.g. lens radome H01Q1/42
• CPC Class Codes: H01Q 19/062 for focusing
• CPC Class Codes: H01Q 21/0025 Modular arrays
• CPC Class Codes: H01Q 21/061 Two dimensional planar arrays
• CPC Class Codes: H01Q 3/2605 Array of radiating elements provided with a feedback control over the element weights, e.g. adaptive arrays
• CPC Class Codes: H01Q 3/34 by electrical means active lenses or reflecting arrays H01Q3/46
• CPC Class Codes: H01Q 3/44 varying the electric or magnetic characteristics of reflecting, refracting, or diffracting devices associated with the radiating element

Abstract

A phased array antenna comprising a two dimensional array of lens enhanced radiator units, each radiator unit comprising: a radiator for generating a radio frequency (RF) signal; and a two dimensional phase variable lens group defining an aperture in a transmission path of the RF signal, the lens group comprising a two dimensional array of individually controllable lens elements enabling a varying transmission phase to be applied to the RF signal across the aperture of the lens group. Also, a unit cell of a lens element in a metamaterial sheet, the unit cell comprising a stack of cell layers, each cell layer comprising a volume of nematic liquid crystal with a controllable dielectric value enabling each cell layer to function as tunable resonator.

Claims

1. A phased array antenna comprising:

a two dimensional array of lens enhanced radiator units, each radiator unit comprising;

a radiator for generating a radio frequency (RF) signal;

a two-dimensional phase variable lens group defining an aperture in a transmission path of the RF signal, the lens group comprising a two dimensional array of individually controllable lens elements enabling a varying transmission phase to be applied to the RF signal across the aperture of the lens group.

2. The antenna of claim 1 wherein the lens groups are formed from a metamaterial sheet.

3. The antenna of claim 1 comprising conductive walls isolating adjacent radiator units from each other.

4. The antenna of claim 1 comprising a control circuit configured to enable the radiators units to operate in a MIMO mode in which the radiator units operate to form multiple concurrent independent beams and a point-to-point mode in which the radiator units operate collectively to form a single high-gain directive beam or multiple optimally shaped beams.

5. The antenna of claim 1 wherein the aperture of each lens group is greater than twice a minimum operating wavelength λ

of the RF signal.

6. The antenna of claim 5 wherein adjacent lens groups are spaced within one and one half the wavelength λ

of each other.

7. The antenna of claim 5 wherein each lens element has an aperture size of approximately half of the wavelength λ

.

8. The antenna of claim 1 wherein a plurality of control conductors are provided about a perimeter each radiator unit for providing a unique configurable control voltage to each of the lens elements within the radiator unit.

9. The antenna of claim 1 wherein each lens element comprises at least one unit cell, each unit cell comprising a stack of cell layers, each cell layer comprising a volume of nematic liquid crystal with a controllable dielectric value enabling each cell layer to function as tunable resonator.

10. The antenna of claim 9 wherein each lens element comprises a two dimensional array of the unit cells.

11. The antenna of claim 9 wherein each cell layer comprises:

first and second double sided substrates defining an intermediate region between them, the first substrate having a first microstrip patch formed on a side thereof that faces the second substrate, the second substrate having a second microstrip patch formed on a side thereof that faces the first substrate;

the liquid crystal being located in a liquid crystal embedded substrate between the first microstrip patch and the second microstrip patch in the intermediate region,

and wherein the first microstrip patch of each cell layer is electrically connected to a common ground and the second microstrip patch of each cell layer is electrically connected to a common control voltage source.

12. The antenna of claim 11 wherein:

the first microstrip patch of each cell layer is electrically connected to the common ground via a first conductive element extending through the first substrate to a first conductive wire located on an opposite side of the first substrate than the first microstrip patch; and

the second microstrip patch of each cell layer is electrically connected to the common control voltage source via a second conductive element extending through the second substrate to a second conductive wire located on an opposite side of the second substrate than the second first microstrip patch;

wherein the first wire and the second wire are substantially RF transparent to the RF signal passing through the cell layer.

13. The antenna of claim 12 wherein the first wire and the second wire are each part of a respective first gridded mesh wire and second gridded mesh wire that extend across the lens element that comprises the unit cell.

14. The antenna of claim 13 where in each unit cell, adjacent cell layers are bonded together by non-conductive adhesive.

15. A method of transmitting RF signals, comprising:

providing a phased array antenna having a two dimensional array of lens enhanced radiator units, each radiator unit comprising;

a radiator for generating a radio frequency (RF) signal; and

a lens group defining an aperture in a transmission path of the RF signal, the lens group comprising a two dimensional array of individually controllable lens elements enabling a varying transmission phase to be applied to the RF signal across the aperture of the lens group;

generating RF signals at the radiators; and

applying control voltages to the lens groups to control a transmission phase of the lens elements across each of the radiator units.

16. The method of claim 15 wherein the control voltages are applied to cause the radiators units to operate in a MIMO mode in which the radiator units operate to form multiple concurrent independent beams.

18. The method of claim 15 wherein each lens element comprises at least one unit cell, each unit cell comprising a stack of cell layers, each cell layer comprising a volume of nematic liquid crystal with a controllable dielectric value enabling each cell layer to function as tunable resonator, wherein the control voltages are applied to control the dielectric values of the cell layers.

19. The method of claim 18 wherein each cell layer comprises:

first and second double sided substrates defining an intermediate region between them, the first substrate having a first microstrip patch formed on a side thereof that faces the second substrate, the second substrate having a second microstrip patch formed on a side thereof that faces the first substrate;

the liquid crystal being located in a liquid crystal embedded substrate between the first microstrip patch and the second microstrip patch in the intermediate region,

and wherein the first microstrip patch of each cell layer is electrically connected to a common ground and the second microstrip patch of each cell layer is electrically connected to a common control voltage source,

wherein the control voltages are applied using the control voltage source.

20. The method of claim 19 wherein:

the first microstrip patch of each cell layer is electrically connected to the common ground via a first conductive element extending through the first substrate to a first conductive wire located on an opposite side of the first substrate than the first microstrip patch; and

the second microstrip patch of each cell layer is electrically connected to the common control voltage source via a second conductive element extending through the second substrate to a second conductive wire located on an opposite side of the second substrate than the second first microstrip patch;

wherein the first wire and the second wire are substantially RF transparent to the RF signal passing through the cell layer.

17. The method of 15 wherein the control voltages are applied to cause the radiators units p to operate in a point-to-point mode in which the radiator units operate collectively to form a single high-gain directive beam or multiple optimally shaped beams.