Metamaterial-Based Phase Shifting Element and Phased Array

Patent metadata

Field	Value
Publication number	US-2016013531-A1
Application number	US-201414330977-A
Country	US
Kind code	A1
Filing date	Jul 14, 2014
Priority date	Jul 14, 2014
Publication date	Jan 14, 2016
Grant date	—

Abstract

A metamaterial-based phase shifting element utilizes a variable capacitor (varicap) to control the effective capacitance of a metamaterial structure in order to control the phase of a radio frequency output signal generated by the metamaterial structure. The metamaterial structure is configured to resonate at the same radio wave frequency as an incident input signal (radiation), whereby the metamaterial structure emits the output signal by way of controlled scattering the input signal. A variable capacitance applied on metamaterial structure by the varicap is adjustable by way of a control voltage, whereby the output phase is adjusted by way of adjusting the control voltage. The metamaterial structure is constructed using inexpensive metal film or PCB fabrication technology including an upper metal “island” structure, a lower metal backplane layer, and a dielectric layer sandwiched therebetween. The varicap is connected between the island structure and a base metal structure that surrounds the island structure.

First claim

1 . A phase shifting element for receiving an input signal having a radio wave frequency and an input phase, and for generating an output signal having said radio wave frequency and having an output phase determined by an applied phase control signal, the phase shifting element comprising:
a metamaterial structure configured to have a fixed capacitance, and configured such that said metamaterial structure resonates at said radio wave frequency; and a variable capacitor configured to generate a variable capacitance that varies in accordance with said applied phase control signal, said variable capacitor being coupled to said metamaterial structure such that an effective capacitance of said metamaterial structure is altered by a corresponding change in said variable capacitance, whereby said metamaterial structure generates said output signal at said output phase determined by said applied phase control signal.

2 . The phase shifting element of claim 1 , wherein said phase control signal comprises a direct-current phase control voltage, and wherein the variable capacitor is configured such that:
when said phase control voltage is applied across said variable capacitor and has a first voltage level, said variable capacitor generates said variable capacitance at a first capacitance level such that said metamaterial structure generates said output signal at an associated first output phase, and when said applied phase control voltage is increased from said first voltage level to a second voltage level, said variable capacitor generates said variable capacitance at a second capacitance level such that said metamaterial structure generates said output signal at an associated second output phase, said second output phase being greater than said first output phase.

3 . The phase shifting element of claim 1 ,
wherein said variable capacitor includes a first terminal connected to said metamaterial structure and a second terminal, wherein said phase shifting element further comprises a conductive structure connected to one of said metamaterial structure and said first terminal of said variable capacitor such that, when said phase control signal is applied to said conductive structure and said second terminal is connected to a ground potential, said variable capacitor generates said associated variable capacitance having a capacitance level that is proportional to said phase control signal.

4 . The phase shifting element of claim 1 , wherein said metamaterial structure comprises:
a first metal layer structure connected to said variable capacitor; an electrically isolated second metal layer structure; and a dielectric layer sandwiched between said first and second metal layer structures, wherein said first and second metal layer structures are cooperatively configured such that said metamaterial structure resonates at said radio wave frequency and has said fixed capacitance.

5 . The phase shifting element of claim 4 , wherein said dielectric layer comprises a lossless dielectric material.

6 . The phase shifting element of claim 4 ,
wherein said first metal layer structure is disposed on an upper dielectric surface of said dielectric layer, wherein said phase shifting element further comprises a third metal layer structure disposed on said upper dielectric surface and spaced from said first metal layer structure, and wherein said variable capacitor includes a first terminal connected to said first metal layer structure and a second terminal connected to said third metal structure.

7 . The phase shifting element of claim 6 ,
wherein said third metal layer structure defines an opening disposed inside an inner peripheral edge, wherein said first metal layer structure is disposed inside said opening such that an outer peripheral edge of said first metal layer structure is separated from the inner peripheral edge of said third metal layer structure by a peripheral gap, and wherein said first, second and third metal layer structures are cooperatively configured such that said metamaterial structure resonates at said radio wave frequency and has said fixed capacitance.

8 . The phase shifting element of claim 7 , wherein said third metal layer structure and said first metal layer structure comprise a single metal.

9 . The phase shifting element of claim 7 , further comprising a metal via structure extending through the dielectric layer and contacting the first terminal.

10 . The phase shifting element of claim 7 , wherein said inner peripheral edge defining said at least one opening in said third metal layer structure and said outer peripheral edge of said first metal layer structure comprise concentric square shapes such that a width of said peripheral gap remains substantially constant around the entire perimeter of said first metal layer structure.

11 . The phase shifting element of claim 4 , wherein the first metal layer structure comprises a patterned planar structure defining one or more open regions.

12 . The phase shifting element of claim 11 , wherein the first metal layer structure comprises:
a peripheral frame portion including said outer peripheral edge; one or more radial arms, each radial arm having a first end integrally connected to the peripheral frame portion and extending inward from the peripheral frame toward a central region of said metamaterial structure; and an inner structure integrally connected to second ends of the one or more radial arms, said inner structure being spaced from said peripheral frame portion by way of said one or more open regions.

13 . A phase shifting apparatus for generating an output signal at an output phase determined by a phase control signal, said apparatus comprising:
a signal source configured to generate a first signal having a radio wave frequency and a first phase; a phase shifting element including: a metamaterial structure configured to have a fixed capacitance, and configured such that said metamaterial structure resonates at said radio wave frequency, and a variable capacitor configured to generate a variable capacitance that varies in accordance with an applied phase control voltage, said variable capacitor being coupled to said metamaterial structure such that an effective capacitance of said metamaterial structure is altered by a corresponding change in said variable capacitance; and a control circuit configured to generate said phase control voltage applied to said variable capacitor at a voltage level determined in accordance with said phase control signal, whereby said metamaterial structure generates said output signal at said output phase determined by said phase control signal.

14 . The phase shifting apparatus of claim 13 , wherein said metamaterial structure comprises:
a first metal layer structure connected to said variable capacitor; an electrically isolated second metal layer structure; and a dielectric layer sandwiched between said first and second metal layer structures, wherein said signal source is disposed over the first metal layer structure such that said first metal layer structure is disposed between said signal source and said dielectric layer, and wherein said first and second metal layer structures are cooperatively configured such that said metamaterial structure resonates at said radio wave frequency and has said fixed capacitance.

15 . The phase shifting apparatus of claim 14 ,
wherein said first metal layer structure is disposed on an upper dielectric surface of said dielectric layer, wherein said phase shifting element further comprises a third metal layer structure disposed on said upper dielectr

Assignees

• Palo Alto Res Ct Inc

Inventors

• Casse Bernard D
• Volkel Armin R
• Liu Victor
• Tuganov Alexander S

Classifications

• H01Q3/46

  Active lenses or reflecting arrays · CPC title

• H01Q3/36

  with variable phase-shifters · CPC title

• H01Q21/08

  the units being spaced along or adjacent to a rectilinear path {(waveguide fed H01Q21/0037)} · CPC title

• H01Q21/065

  Patch antenna array · CPC title

• H01P1/184 Primary

  Strip line phase-shifters (H01P1/181, H01P1/185, H01P1/19 take precedence) · CPC title