Reconfigurable geometric metasurfaces with optically tunable materials

Patent metadata

Field	Value
Publication number	US-2021028547-A1
Application number	US-201916522297-A
Country	US
Kind code	A1
Filing date	Jul 25, 2019
Priority date	Jul 25, 2019
Publication date	Jan 28, 2021
Grant date	—

Abstract

An apparatus includes two or more groups of antennas, each including two or more patches of optically tunable material providing two or more antennas. The tunable geometric metasurface also includes a control circuit including a plurality of switches providing current sources and a ground voltage. The plurality of switches are coupled to respective ones of the patches of optically tunable material in each of the groups of antennas via first electrodes. The ground voltage is coupled to respective ones of the patches of optically tunable material in each of the groups of antennas via second electrodes. The control circuit is configured to modify states of the antennas in each of the groups of antennas utilizing the first electrodes and the second electrodes to adjust reflectivity of the patches of optically tunable material to provide a tunable geometric metasurface.

First claim

What is claimed is:

1 . An apparatus comprising:
two or more groups of antennas, each group of antennas comprising two or more patches of optically tunable material providing two or more antennas; and a control circuit comprising a plurality of switches providing current sources and a ground voltage, the plurality of switches being coupled to respective ones of the two or more patches of optically tunable material in each of the two or more groups of antennas via first electrodes, the ground voltage being coupled to respective ones of the two or more patches of optically tunable material in each of the two or more groups of antennas via second electrodes; wherein the control circuit is configured to modify states of the two or more antennas in each of the two or more groups of antennas utilizing the first electrodes and the second electrodes to adjust reflectivity of the patches of optically tunable material to provide a tunable geometric metasurface.

2 . The apparatus of claim 1 , wherein each of the two or more groups of antennas comprises three or more patches of optically tunable material providing three or more antennas.

3 . The apparatus of claim 1 , wherein the control circuit is configured to modify the states of the two or more patches of optically tunable material in each of the two or more groups of antennas such that a single one of the antennas in each of the two or more groups of antennas has higher reflectively than other ones of the antennas in that group of antennas.

4 . The apparatus of claim 1 , wherein the two or more patches of optically tunable material of each of the two or more groups of antennas have a same orientation over a top surface of a substrate.

5 . The apparatus of claim 1 , wherein the two or more patches of optically tunable material of a first one of the two or more groups of antennas has a first orientation over a top surface of a substrate and wherein the two or more patches of the optically tunable material of a second one of the two or more groups of antennas has a second orientation over the top surface of the substrate different than the first orientation.

6 . The apparatus of claim 1 , wherein a given one of the two or more patches of optically tunable material in a given one of the plurality of groups of antennas comprises chalcogenide phase change material, and wherein the control circuit is configured to modify the state of the given antenna provided by the given patch of optically tunable material by providing a current from the first electrode coupled to the given patch of optically tunable material to the second electrode coupled to the given patch of optically tunable material to heat the chalcogenide phase change material to change a phase of the chalcogenide phase change material from one of crystalline and amorphous to the other one of crystalline and amorphous.

7 . A semiconductor structure comprising:
a substrate; a patch of optically tunable material disposed over the substrate; a first electrode coupled to the patch of optically tunable material and a switch providing a current source; and a second electrode coupled to the patch of optically tunable material and a ground voltage; wherein the first electrode and the second electrode are configured to modify a state of the patch of optically tunable material to adjust a reflectivity of the patch of optically tunable material.

8 . The semiconductor structure of claim 7 , wherein the patch of optically tunable material comprises a chalcogenide phase-change material, and wherein the first electrode and the second electrode are configured to modify the state of the chalcogenide phase-change material via heating to change the chalcogenide phase-change material between an amorphous and a crystalline phase.

9 . The semiconductor structure of claim 8 , wherein the chalcogenide phase-change material comprises at least one of germanium antinomy telluride, germanium telluride, antimony telluride and silver antimony telluride.

10 . The semiconductor structure of claim 7 , wherein the optically tunable material comprises an electrically tunable plasmonic material.

11 . The semiconductor structure of claim 10 , wherein the electrically tunable plasmonic material comprises at least one of graphene, carbon nanotubes, a metal oxide and a metal nitride.

12 . The semiconductor structure of claim 7 , wherein the optically tunable material comprises a metal-insulator transition material.

13 . The semiconductor structure of claim 12 , wherein the metal-insulator transition material comprises vanadium oxide.

14 . The semiconductor structure of claim 7 , further comprising:
a first dielectric layer disposed between the substrate and the patch of optically tunable material; a second dielectric layer disposed over the patch of optically tunable material; and a transparent conductor disposed over the second dielectric layer; wherein the first electrode and the second electrode are disposed over the transparent conductor at opposite ends of the patch of optically tunable material.

15 . The semiconductor structure of claim 14 , further comprising a metal mirror disposed between the substrate and the first dielectric layer.

16 . The semiconductor structure of claim 7 , further comprising:
a first transparent conductor disposed between the substrate and the patch of optically tunable material; a second transparent conductor disposed over the patch of optically tunable material; a first insulator layer disposed over the substrate adjacent a first end of the patch of optically tunable material; and a second insulator layer disposed over the substrate adjacent a second end of the patch of optically tunable material; wherein the first electrode is disposed over the first insulator layer and the second electrode is disposed between the substrate and the second insulator layer.

17 . The semiconductor structure of claim 16 , further comprising a metal mirror disposed between the substrate and the first insulator layer, the first transparent conductor and the second insulator layer, the metal mirror providing the second electrode.

18 . The semiconductor structure of claim 7 , further comprising:
one or more additional patches of optically tunable material; and one or more additional electrodes coupled to respective ones of the one or more additional patches of optically tunable material and one or more additional switches providing one or more additional current sources; wherein each of the one or more additional patches of optically tunable material is coupled to the second electrode providing the ground voltage; and wherein the second electrode and the one or more additional electrodes are configured to modify states of the one or more additional patches of optically tunable material to adjust reflectivity of the one or more additional patches of optically tunable material.

19 . A method comprising:
determining a desired interference effect for a plurality of groups of antennas, each group of antennas comprising two or more patches of optically tunable material providing two or more antennas, the two or more patches of optically tunable material being coupled via first electrodes to switches providing current sources and via a second electrode to a ground voltage; and utilizing a control circuit to modify states of the antennas in each of the two or more groups of antennas to provide the desired interference effect, the control circuit comprising a plurality of switches providing current sources and a ground vo

Assignees

• IBM

Inventors

• Falk Abram L
• Rosenberg Jessie Carrigan
• Lai Kafai
• Farmer Damon Brooks

Classifications

• H01Q15/0086 Primary

  said selective devices having materials with a synthesized negative refractive index, e.g. metamaterials or left-handed materials · CPC title

• H01Q9/0442 Primary

  with particular tuning means · CPC title

• H01Q3/44

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

• H01Q21/065

  Patch antenna array · CPC title

• H01Q3/30

  varying the {relative} phase {between the radiating elements of an array (H01Q3/2605, H01Q3/2658, H01Q3/2682, H01Q3/44 take precedence)} · CPC title