U.S. patent application number 13/403328 was filed with the patent office on 2013-08-29 for electromagnetic meta-materials.
This patent application is currently assigned to Lockheed Martin Corporation. The applicant listed for this patent is Andy Nagerl, John Watkins. Invention is credited to Andy Nagerl, John Watkins.
Application Number | 20130224405 13/403328 |
Document ID | / |
Family ID | 49003152 |
Filed Date | 2013-08-29 |
United States Patent
Application |
20130224405 |
Kind Code |
A1 |
Nagerl; Andy ; et
al. |
August 29, 2013 |
ELECTROMAGNETIC META-MATERIALS
Abstract
Apparatus including meta-materials and methods for making the
apparatus are described. Circuit components, such as split ring
resonators and/or spiral loops, may be formed on substrates to form
the meta-materials. The meta-materials may be used in various types
of apparatus. The methods of making the apparatus may include
forming two and/or three-dimensional structures comprising the
meta-materials.
Inventors: |
Nagerl; Andy; (Owego,
NY) ; Watkins; John; (Berkshire, NY) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Nagerl; Andy
Watkins; John |
Owego
Berkshire |
NY
NY |
US
US |
|
|
Assignee: |
Lockheed Martin Corporation
Bethesda
MD
|
Family ID: |
49003152 |
Appl. No.: |
13/403328 |
Filed: |
February 23, 2012 |
Current U.S.
Class: |
428/34.1 ;
428/116; 428/117 |
Current CPC
Class: |
H05K 7/14 20130101; Y10T
428/24157 20150115; H05K 1/024 20130101; H05K 9/0086 20130101; B32B
3/28 20130101; B32B 3/12 20130101; Y10T 428/13 20150115; H05K
1/0236 20130101; Y10T 428/24149 20150115 |
Class at
Publication: |
428/34.1 ;
428/116; 428/117 |
International
Class: |
B32B 3/12 20060101
B32B003/12 |
Claims
1. A meta-material, comprising: a plurality of corrugated
substrates comprising a first corrugated substrate and a second
corrugated substrate, the first corrugated substrate comprising a
plurality of first peaks and a plurality of first troughs, and the
second corrugated substrate comprising a plurality of second peaks
and a plurality of second troughs, wherein each of the first and
second corrugated substrates has at least one circuit component
formed thereon, and wherein the first peaks are substantially
aligned with the second peaks and the first troughs are
substantially aligned with the second troughs.
2. The meta-material of claim 1, wherein the first corrugated
substrate and the second corrugated substrate form in combination
at least part of a honeycomb structure.
3. The meta-material of claim 1, wherein the at least one circuit
component is a split ring resonator.
4. The meta-material of claim 1, wherein the at least one circuit
component comprises a spiral loop.
5. The meta-material of claim 1, further comprising an adhesive
layer disposed between the first corrugated substrate and the
second corrugated substrate and configured to maintain the first
corrugated substrate and the second corrugated substrate in a fixed
relation relative to each other.
6. The meta-material of claim 5, further comprising a filler
material disposed between at least a portion of the first
corrugated substrate and the second corrugated substrate.
7. The meta-material of claim 6, wherein the filler material
comprises a syntactic foam.
8. The meta-material of claim 1, further comprising a filler
material disposed between at least a portion of the first
corrugated substrate and the second corrugated substrate.
9. The meta-material of claim 8, wherein the filler material
comprises a syntactic foam.
10. A meta-material, comprising: a slab of a first material; and a
plurality of substrate strips disposed within the first material
and arranged in an array, wherein a first substrate strip of the
plurality of substrate strips has a circuit component formed
thereon.
11. The meta-material of claim 10, wherein the slab of material
comprises syntactic foam.
12. The meta-material of claim 10, wherein the first substrate
strip comprises a printed circuit board.
13. The meta-material of claim 10, wherein the circuit component is
a split ring resonator.
14. The meta-material of claim 10, wherein the first substrate
strip and a second substrate strip of the plurality of substrate
strips are disposed at a substantially right angle relative to each
other.
15. An apparatus comprising the meta-material of claim 10, and
further comprising: a container in which the slab is disposed,
wherein the first substrate strip passes at least partially through
a first surface of the container.
16. A meta-material, comprising: a plurality of substrate strips
comprising a first substrate strip and a second substrate strip,
wherein each of the first and second substrate strips includes at
least one circuit component formed thereon, and wherein the second
substrate strip is disposed at least partially within a slot of the
first substrate strip.
17. The meta-material of claim 16, wherein each of the plurality of
substrate strips is disposed at least partially within a slot of at
least one other substrate strip of the plurality of substrate
strips.
18. The meta-material of claim 17, wherein the substrate strips of
the plurality of substrate strips are interconnected to form a grid
pattern.
19. The meta-material of claim 17, wherein the substrate strips of
the plurality of substrate strips are interconnected for form a
cube.
20. The meta-material of claim 16, wherein the at least one circuit
component comprises a spiral loop.
Description
BACKGROUND
[0001] 1. Field
[0002] The present application relates to electromagnetic
meta-materials.
[0003] 2. Related Art
[0004] Meta-materials are engineered materials that can exhibit a
negative magnetic permeability. Magnetic permeability is often
designated by "mu" (.mu.), and therefore meta-materials are
sometimes referred to as mu negative (MNG, or .mu. negative)
materials.
BRIEF SUMMARY
[0005] According to one aspect of the present application, a
meta-material is provided. The meta-material comprises a plurality
of corrugated substrates comprising a first corrugated substrate
and a second corrugated substrate. The first corrugated substrate
comprises a plurality of first peaks and a plurality of first
troughs, and the second corrugated substrate comprises a plurality
of second peaks and a plurality of second troughs. Each of the
first and second corrugated substrates may have at least one
circuit component formed thereon. The first peaks may be
substantially aligned with the second peaks and the first troughs
may be substantially aligned with the second troughs.
[0006] According to another aspect of the present application, a
meta-material is provided, comprising a slab of a first material.
The meta-material further comprises a plurality of substrate strips
disposed within the first material and arranged in an array. A
first substrate strip of the plurality of substrate strips may have
a circuit component formed thereon.
[0007] According to another aspect of the present application, an
apparatus is provided. The apparatus comprises a meta-material
including a slab of a first material in which are embedded
substrate strips including circuit components thereon. The
apparatus may further comprise a container in which the slab is
disposed. The first substrate strip passes at least partially
through a first surface of the container.
[0008] According to another aspect of the present application, a
meta-material is provided comprising a plurality of substrate
strips. The plurality of substrate strips includes a first
substrate strip and a second substrate strip. Each of the first and
second substrate strips includes at least one circuit component
formed thereon. The second substrate strip may be disposed at least
partially within a slot of the first substrate strip.
BRIEF DESCRIPTION OF DRAWINGS
[0009] Various aspects and embodiments of the technology will be
described with reference to the following figures. It should be
appreciated that the figures are not necessarily drawn to scale.
Items appearing in multiple figures are indicated by the same or
similar reference number in all figures in which they appear.
[0010] FIG. 1 illustrates a meta-material comprising corrugated
substrates with circuit components formed thereon, according to a
non-limiting embodiment.
[0011] FIG. 2 is a flowchart illustrating a non-limiting process
flow for making a meta-material of the type shown in FIG. 1.
[0012] FIG. 3 illustrates a meta-material comprising a slab of
material in which substrate strips are disposed, according to
another non-limiting embodiment.
[0013] FIG. 4 is a flowchart illustrating a non-limiting process
flow for making a meta-material of the type shown in FIG. 3.
[0014] FIG. 5 illustrates an apparatus for making a meta-material,
according to a non-limiting embodiment.
[0015] FIG. 6 is a flowchart illustrating a non-limiting process
flow for making a meta-material using the apparatus of FIG. 5.
[0016] FIG. 7. illustrates a meta-material comprising a plurality
of interconnected substrate strips having circuit components
thereon, according to another non-limiting embodiment.
[0017] FIG. 8 illustrates an alternative configuration of a
meta-material of the type shown in FIG. 7.
[0018] FIG. 9 is a flowchart illustrating a non-limiting process
flow for making a meta-material of the type shown in FIG. 7.
[0019] FIGS. 10A-10E illustrates non-limiting examples of circuit
components which may be used to form meta-materials according to
various aspects of the present application.
DETAILED DESCRIPTION
[0020] Applicants describe herein electromagnetic meta-materials,
methods for making such materials, and apparatus including such
materials. According to various aspects, the electromagnetic
meta-materials may include one or more substrates on which one or
more circuit components may be formed, such as split ring resonator
circuits. The substrates may take various forms and may be made of
various materials. Furthermore, two or more substrates may be
combined to form a two dimensional or three dimensional structure.
In some such embodiments, a filler material may be disposed between
substrates, for example to tune the electromagnetic behavior of the
meta-material.
[0021] Some aspects of the present application provide methods for
fabricating electromagnetic meta-materials of the types described
herein. The methods may involve, in some non-limiting embodiments,
forming circuit components on a substrate, and then positioning the
substrates suitably relative to each other to form the
meta-material. For example, split ring resonator circuits may be
formed on one or more substrates, and then the substrates may be
combined in any suitable manner to form a two-dimensional or
three-dimensional electromagnetic meta-material.
[0022] Some aspects of the present application are directed to
apparatus (or structures) which may be used in the fabrication of
meta-materials of at least some of the types described herein. In
some embodiments, the apparatus may facilitate formation of a
meta-material in which substrates having circuit components formed
thereon are embedded (or encased) within a filler material. The
filler material may facilitate maintaining the substrates in a
desired position relative to each other, and may be used, in some
non-limiting embodiments, to tune the electromagnetic behavior of
the meta-material.
[0023] The aspects described above, as well as additional aspects,
are described further below. These aspects may be used
individually, all together, or in any combination of two or more,
as the technology is not limited in this respect, unless otherwise
stated.
[0024] According to a first non-limiting aspect of the present
application, an electromagnetic meta-material may comprise two or
more corrugated substrates, on which one or more circuit components
may be formed. The corrugated substrates may be substantially
aligned. For example, peaks of one of the corrugated substrates may
substantially align with peaks of the other corrugated
substrate(s). Similarly, troughs of one of these substrates may
substantially align with troughs of the other substrate. A
non-limiting example is illustrated in FIG. 1.
[0025] As shown, the electromagnetic meta-material 100 comprises
multiple corrugated substrates 102a and 102b. For purposes of
simplicity, only two corrugated substrates are illustrated.
However, it should be appreciated that electromagnetic
meta-materials according to the present aspect may, and in some
scenarios will, include more than two corrugated substrates. For
instance, tens, hundreds, thousands, or any suitable number of
substrates may be used to form a meta-material of desired
dimensions. As shown, each of the corrugated substrates 102a and
102b may include circuit components 104. In the non-limiting
embodiment of FIG. 1, each of the corrugated substrates 102a and
102b includes four circuit components 104 on each corrugated
segment, positioned across the width W.
[0026] The substrates 102a and 102b may be formed of any suitable
material. For example, in one non-limiting embodiment, the
substrates 102a and 102b are formed of printed circuit boards
(PCBS). The material may, in some embodiments, be selected to
provide a desired electromagnetic property (e.g., a desired
dielectric constant). For instance, according to one non-limiting
embodiment, the substrates 102a and 102b are formed of a low
dielectric constant material. In some embodiments, the substrates
102a and 102b may be formed of a material that is substantially
flexible, which may facilitate formation of the corrugated
structures illustrated in FIG. 1. However, it should be appreciated
that any suitable type of material may be used for the substrates
102a and 102b, and that the various aspects of the present
application are not limited to using any particular type of
material as a substrate material, unless otherwise stated.
[0027] The corrugated substrates 102a and 102b may have any
suitable dimensions, including any suitable length L, any suitable
width W, and any suitable height H. According to one non-limiting
embodiment, the width W may take any suitable value between
approximately 2 inches and 20 inches (e.g., approximately 5 inches,
approximately 10 inches, etc.), between approximately 6 and 18
inches (e.g., 6 inches, 8 inches, 10 inches, 12 inches, etc.),
between approximately 1 and 6 inches (e.g., 2 inches, 3 inches,
etc.), less than approximately 3 inches, or may take any other
suitable value. Similarly, the height H of corrugated substrates
102a and 102b may fall within a range from approximately 0.1 to 1
inch (e.g., 0.25 inches), between approximately 0.5 inches and 2
inches, less than 3 inches, or may take any other suitable values,
as non-limiting examples. The length L may also assume any suitable
value, for example ranging between 2 and 20 inches (e.g., 5 inches,
10 inches, 15 inches, or any other suitable value), as a
non-limiting example. The length L may be greater than the width W.
In some non-limiting embodiments, the length of the corrugated
substrate may be substantially greater than the width of the
substrates. In some such embodiments, the substrates may be
referred to as corrugated ribbons or corrugated strips, though it
should be appreciated that other terminology may also be used to
refer such structures.
[0028] The corrugated substrates 102a and 102b may include any
suitable number of corrugations, and therefore any suitable number
of corrugated segments. The segments may have any suitable length
L.sub.S. For example, the length L.sub.S may fall within a range
from approximately 0.1 inches to approximately 1 inch (e.g., 1/4
inch), from approximately 0.5 inches to approximately 2 inches,
less than 2 inches, less than 1 inch (e.g., 1/4 inch, 1/2 inch,
etc.), or may take any suitable value. Furthermore, not all
segments need have the same length. For example, peak and trough
segments may differ in length from each other. Alternatively, or in
addition, the length of vertical segments (e.g., segments
perpendicular to the adhesive layer 114, described further below)
may differ in length from the length of peak segments and/or trough
segments. Thus, the present aspect is not limited to substrates
having any particular number or dimensions of corrugated segments.
Therefore, it should be appreciated that the number of corrugations
illustrated in FIG. 1 is non-limiting, as other numbers are
possible.
[0029] As mentioned, the circuit components 104 may represent any
suitable circuit component, or circuit. Also, as will be
appreciated further from the non-limiting examples illustrated in
FIGS. 3, 5, and 10A-10E, it should be appreciated that the
components need not be connected within an electric circuit.
Rather, as will be described, according to some non-limiting
embodiments the circuit components may comprise conductive
structures whose terminals are not directly connected to any other
circuit components. According to a non-limiting embodiment, circuit
components 104 represent split ring resonators. According to
another non-limiting embodiment, the circuit components 104 may be
spiral loops (e.g., conductive traces formed in a spiral). In both
such embodiments, the terminals of the conductive structures need
not be connected to any other circuit components. However,
alternative circuit components or circuits may be implemented.
[0030] In those embodiments in which a split ring resonator or a
spiral loop is formed on a corrugated substrate, the split ring
resonator or spiral loop may have any suitable designs. For
example, the split ring resonator or spiral loop may have any
suitable dimensions, any suitable shapes and may be formed of any
suitable material and in any suitable manner. Non-limiting examples
of suitable circuit components 104 are illustrated in FIGS.
10A-10E.
[0031] In the non-limiting example of FIG. 10A, a split ring
resonator 1002 is illustrated. As shown, the split ring resonator
1002 may include a substantially square trace (e.g., a copper
trace, a copper wire, or any other suitable conductive structure),
with a single split 1004 between two ends of the trace. The split
ring resonator may have any suitable dimension D.sub.1.
[0032] FIG. 10B illustrates an alternative circuit component
design, showing a spiral loop 1006. The spiral loop may have any
suitable diameter D.sub.2 and be formed of any suitable material
(e.g., a copper trace or wire, aluminum, are any other suitable
material).
[0033] A further non-limiting embodiment is illustrated in FIG.
10C, showing a substantially circular loop 1008 having a split 1010
between two end. The loop 1008 may have any suitable diameter
D.sub.3 and be formed of any suitable material.
[0034] FIG. 10D illustrates a further non-limiting embodiment,
illustrating a spiral loop 1012 with a diameter D4.
[0035] In some embodiments, the circuit component may include
multiple disconnected loops or rings. For example, FIG. 10E
illustrates a non-limiting example in which two substantially
square rings 1014a and 1014b are shown. The outer ring 1014b may
have any suitable length D.sub.5. Respective slits 1016a and 1016b
may be formed in each loop, as shown, and the respective slits may
be offset from each other. Other configurations are also
possible.
[0036] In any of FIGS. 10A-10E, the illustrated structures may be
formed of any suitable material (e.g., any suitable conducting
material, such as copper, aluminum or any other suitable
material).
[0037] Also, any suitable values for the dimensions of the
structures in FIGS. 10A-10E may be used. In some embodiments, the
dimensions of the illustrated structures may be chosen to provide
desired electromagnetic behavior. For example, the dimensions may
control a resonance frequency of the illustrated structures, and
thus may be selected to provide a desired resonance frequency. As a
non-limiting example, the dimension D.sub.1 may control the
resonance frequency of the loop 1002 in FIG. 10A. Thus, the value
of D.sub.1 may be selected such that the loop 1002 has a desired
resonance frequency. However, not all embodiments are limited in
this respect.
[0038] As non-limiting examples, the values of D1-D5 may be between
approximately 0.1 inches and approximately 2 inches (e.g., 1/4
inch, 1/2 inch, 3/4 inch, etc.), between approximately one inch and
four inches (e.g., two inches, three inches, etc.), may be between
approximately one inch and two inches, may be less than
approximately four inches, less than approximately two inches
(e.g., 0.25 inches, 0.5 inches, one inch, etc.), or may have any
other suitable values.
[0039] Referring again to FIG. 1, it should be appreciated that any
number of circuit components 104 may be included, and that
substrates 102a and 102b need not include an identical number of
circuit components. Furthermore, each segment of the corrugated
substrates 102a and 102b need not include the same number of
circuit components, or any circuit components at all. For example,
according to an alternative embodiment to that illustrated in FIG.
1, circuit components may only be included on the peak segments
106a and 106b of the corrugated substrates. According to an
alternative embodiment, circuit components 104 may only be included
on the trough segments 108a and 108b of the corrugated substrates.
Alternatively, circuit components may only be included on the
vertical wall segments 110a and 110b of the substrates 102a and
102b. Any combination of the segments of substrates 102a and 102b
may include circuit components formed thereon in any suitable
manner (as discussed further below).
[0040] As also illustrated in FIG. 1, in some non-limiting
embodiments of the present aspect, the corrugated substrates 102a
and 102b may be substantially aligned with each other. For example,
the substrates 102a and 102b may be substantially aligned such that
peak segments of the two substrates substantially align with each
other and trough segments of the two substrates substantially align
with each other. For instance, as illustrated in FIG. 1, peak
segment 106a of corrugated substrate 102a substantially aligns with
peak segment 106b of corrugated substrate 102b. Similarly, trough
segment 108a of corrugated substrate 102a substantially aligns with
trough segment 108b of corrugated substrate 102b. Moreover, wall
segment 110a of corrugated substrate 102a substantially aligns with
wall segment 110b of corrugated substrate 102b. The illustrated
alignment is one non-limiting example of suitable alignment, as
other alignment configurations may also be implemented.
[0041] As will be described further below with respect to FIG. 2,
alignment of the corrugated substrates 102a and 102b may be
facilitated by alignment features on one or more the substrates.
For example, alignment holes 112 may be included to facilitate
alignment of the substrates.
[0042] The electromagnetic meta-material of FIG. 1 may, optionally,
further include a structure for maintaining the substrates in a
desired alignment or configuration with respect to each other. For
example, an optional adhesive layer 114 may be included. The
optional adhesive layer 114 may be included to facilitate
maintaining the fixed alignment between the corrugated substrates
102a and 102b. For example, each of corrugated substrates 102a and
102b may be fixedly adhered to a respective surface of the adhesive
layer 114. In this manner, positioning of the corrugated substrates
with respect to each other may be maintained. The shape of the
corrugated substrates may also be maintained at least in part by
the adhesive layer.
[0043] In those embodiments in which an adhesive layer 114 is
included, the adhesive layer may be formed of any suitable
material. For example, the adhesive layer 114 may comprise
polyamide, a liquid crystal polymer, a plastic, or any other
suitable material. In some embodiments, the adhesive layer may be
formed of a material providing a desired electromagnetic property,
such as a desired dielectric constant. For example, a material of
low dielectric constant may be used as the adhesive layer 114.
Thus, it should be appreciated that in those embodiments in which
an adhesive layer is included, the adhesive layer is not limited to
being formed of any particular material.
[0044] In some embodiments, an optional filler material may be
included in the meta-material 100. The filler may be included to
provide desired electromagnetic behavior (e.g., to tune the
meta-material), may be provided to support the substrates (e.g., to
maintain their shape), or may be provided for any other reason. As
a non-limiting example, optional filler material 116 may be
disposed between at least part of the corrugated substrate 102a and
part of the corrugated substrate 102b. As illustrated, in this
non-limiting example, the optional filler material may be disposed
under a peak segment 106a of corrugated substrate 102a, for example
between the corrugated substrate 102a and the adhesive layer 114.
The filler material may be included for any suitable reason, for
example to tune the frequency operation of the electromagnetic
meta-material, to provide support for the corrugated substrate
102a, or for any other suitable reason.
[0045] The optional filler material may be any suitable material
for providing the desired function (e.g., a supporting function, a
frequency tuning function, etc.). According to some embodiments,
the filler material 116 may be formed of a low dielectric constant
material. The material may be chosen to have a dielectric constant
which may be used to tune the frequency behavior of the
electromagnetic meta-material (e.g., to tune the resonance
frequency of the meta-material, or otherwise). The filler material
may be foam (e.g., syntactic foam) in some non-limiting
embodiments. According to some embodiments, the filler material 116
may have a dielectric constant that varies with position. For
example, the filler material 116 may have a graded dielectric
constant.
[0046] It should be appreciated that the structure illustrated in
FIG. 1 may represent only part of a meta-material. For example, the
illustrated structure may be repeated in the direction of H (e.g.,
additional substrates may be disposed above and/or below substrates
102a and 102b), L (e.g., additional substrates may be disposed to
the right and/or left of substrates 102a and 102b), and/or W (e.g.,
additional substrates may be disposed in front of and/or behind the
substrates 102a and 102b). Other orientations are also
possible.
[0047] According to an aspect of the present application, a method
of fabricating an electromagnetic meta-material comprising two or
more corrugated substrates having circuit components formed
thereon, such as the meta-material 100 of FIG. 1, is provided. FIG.
2 illustrates a non-limiting example of such a process.
[0048] As shown, the method 200 may begin at step 202 by forming
circuit components on the substrates (e.g., split ring resonators,
spiral loop structure, or other suitable circuit components). In
some non-limiting embodiments, the circuit components may be formed
by printing them on a substrate (e.g., with an inkjet printer or
other suitable printing device), though not all embodiments are
limited in this manner. Other manners of forming circuit components
may be used. For example, non-limiting alternatives include
depositing and etching electrical traces, fastening a circuit chip
(e.g., a flexible circuit or any other type of circuit) to the
substrate, or any other suitable manner. In those non-limiting
embodiments in which the circuit components are printed, the
printing may be performed using any suitable technique, such as
laser inkjet printing, photolithographic printing, or any other
suitable technique.
[0049] In step 204, alignment holes (e.g., alignment holes 112 in
FIG. 1) may be formed in the substrates. Any suitable technique may
be used for forming the alignment holes, such as etching, drilling,
using a punch, or any other suitable technique.
[0050] As mentioned previously, alignment holes represent a
non-limiting example of an alignment feature which may be used to
facilitate alignment of the substrates. If features other than
holes are used for alignment, such features may be formed at step
204.
[0051] While step 204 is illustrated as occurring after step 202,
it should be appreciated that step 204 may alternatively be
performed prior to printing of the circuit components on the
substrates.
[0052] In step 206, the substrates may be creased or corrugated to
assume the shapes illustrated in FIG. 1. The creasing or
corrugation may be performed in any suitable manner.
[0053] In step 208, the corrugated substrates may be stacked in any
suitable manner to form an electromagnetic meta-material of any
desired size and shape. For example, as illustrated in FIG. 1, one
or more corrugated substrates may be stacked upon one or more
different corrugated substrates. If an optional adhesive layer is
to be used (e.g., optional adhesive layer 114 of FIG. 1), it may be
provided at this stage of the method 200. For example, step 208 may
comprise adhering one or more substrates to an adhesive layer in a
desired stacking relationship.
[0054] In step 210, filler material is optionally provided at
suitable locations, for example as illustrated in FIG. 1 in terms
of optional filler material 116. The optional nature of step 210 is
indicated by the dashed lining in FIG. 2. Again, the filler
material may optionally be a foam material (e.g., syntactic foam),
or any other suitable material. If filler material is not inserted,
the space between corrugated substrate 102a and 102b may simply be
an air gap.
[0055] According to another non-limiting aspect of the present
application, an electromagnetic meta-material comprises a slab of a
first material in which are disposed distinct substrates on which
one or more circuit components are formed. The substrates may be
disposed within the slab of material (e.g., encased within the
slab, embedded within the slab, or otherwise disposed at least
partially within the slab) in an array of any suitable orientation.
For example, substrates may be disposed at substantially 90.degree.
with respect to each other. A non-limiting example illustrated in
FIG. 3.
[0056] As shown, the electromagnetic meta-material 300 includes a
slab 302 (FIG. 3 illustrates a cut-away view of the slab) of first
material, in which slits 304 are formed. It should be appreciated
that the terminology used herein is not limiting, and that various
terms may be used to describe the illustrated structures. For
example, slab 302 may alternatively be referred to as a "block" of
material or a "body" of material, as non-limiting examples.
Similarly, the slits 304 may alternatively be referred to as
"slots," as a non-limiting example. Thus, the slab 302 may be
referred to in some embodiments as a slotted dielectric slab. Also,
it should be appreciated that the slits in some embodiments may
more generally be openings, not necessarily having a slit
structure.
[0057] As shown, a plurality of substrates may be disposed within
respective slits 304 in the slab 302. In some non-limiting
embodiments, the substrates may have a relatively small width W
compared to the length L, and therefore may be referred to as
substrate strips for purposes of explanation. The present
embodiment assumes such a configuration, with FIG. 3 illustrating
substrate strips 306a and 306b. The substrate strips may be
disposed within slits oriented substantially at a right angle
.alpha. with respect to each other. However, it should be
appreciated that other angles of orientation may also be
implemented.
[0058] The slab 302 may be formed of any suitable material.
According to a non-limiting embodiment, the slab of material may
comprise a syntactic foam. In some non-limiting embodiments, the
slab of material may be formed of a material providing a desired
dielectric constant. For example, given that the slab of material
may effectively fill spaces between substrate strips 306a and 306b,
the material may be used to tune the electromagnetic properties of
the electromagnetic meta-material 300, e.g., the material of slab
302 may help control the resonance frequency of the meta-material
300. Accordingly, the material forming slab 302 may be selected to
have any suitable dielectric constant.
[0059] The slits 304 may have any suitable dimensions. According to
a non-limiting embodiment, slits 304 may be sufficiently sized to
accommodate substrate strips 306a and 306b. For example, the slit
304 may be of substantial size to allow insertion of the strips
into the slab 302, but may be suitably sized to maintain a
sufficient pressure fit of the substrate strips, to maintain the
substrate strips in a substantially fixed position. For example,
the slits may have a dimension slightly less than the width W. In a
non-limiting example, the substrate strips may have a width W of
approximately 1 inch, such that each of the slits 304 may similarly
have a width of approximately, but slightly less than, 1 inch.
Alternative dimensions are possible.
[0060] Any suitable number of slits 304 may be provided in the slab
302 of material. According to a non-limiting embodiment, one slit
per substrate strip may be provided. Alternative configurations are
possible.
[0061] As will be described further below, the slits 304 may be
formed in the slab 302 in any suitable manner. According to a
non-limiting embodiment, the slab 302 may initially be formed as a
substantially solid slab, without slits therein. Subsequently,
slits may be formed in the slab, for instance using a cutting tool.
Alternative manners of forming slits 304 are also possible.
[0062] The substrate strips 306a and 306b may be similar to
corrugated substrates 102a and 102b, but without the corrugations
(e.g., the substrate strips 306a and 306b may be substantially
planar). The substrate strips 306a and 306b may be formed of any
suitable material, may include any suitable dimensions, and may
include any suitable type and number of circuit components formed
thereon. For example, the substrate strips may have any of the
features previously described with respect to substrates 102a and
102b. As a non-limiting example, each of substrate strips 306a and
306b includes five spiral loop resonators 308, as shown. However,
alternative numbers and shapes are possible.
[0063] FIG. 4 illustrates a method of fabricating an
electromagnetic meta-material having a configuration like that
illustrated in FIG. 3, in which one or more substrate strips of the
type illustrated are embedded in a slab of material. As shown, the
method 400 begins at step 402 by forming slits 304 (or slots) in a
top surface 305 of the slab 302. In this non-limiting example, the
slab 302 may be a foam material (e.g., a syntactic foam), or any
other suitable material, e.g., a suitable dielectric material. The
slits may be formed by machining them, broaching them, or using any
other suitable technique. As an alternative to step 402, the slab
may simply be molded in a manner resulting in the presence of
slits.
[0064] At step 404, substrate strips 306a and 306b may be formed.
This may be done in any suitable manner. For example, the substrate
strips may be cut out of a larger sheet of substrate material, or
may be formed in any other suitable manner. Similarly, the circuit
components 308 may be formed on the substrate strips 306a and 306b
in any suitable manner, for instance using any of the techniques
previously described herein for forming circuit components on
substrates.
[0065] At step 406, the substrate strips may be inserted into the
slab 302 of material, in any suitable manner.
[0066] Optionally, at step 408, the substrate strips 306a and 306b
may be fastened to the slab 302. For example, the substrate strips
may be fastened to (or within) the slab using glue, a tack (e.g.,
tacks in both the bottom and top ends of the substrate strips), or
any other suitable manner of fastening. Alternatively, as
previously mentioned, these substrate strips may be substantially
fixed relative to the slab due to a pressure fit of the strips
within the slab.
[0067] The two dimensional configuration illustrated in FIG. 3 may
be further extended in some non-limiting embodiments by placing
substrate strips on the top and/or bottom surfaces of the slab 302.
For example, the top surface 305 may have one or more substrate
strips disposed thereon. The substrate strips 306a and 306b may
then be suitably positioned to slide past any substrate strips
disposed on the surface 305. Subsequently, a second slab of the
configuration illustrated in FIG. 3 may be disposed upon the slab
illustrated in FIG. 3, thus forming a three dimensional
structure.
[0068] According to another non-limiting aspect of the present
application, an apparatus and method of encapsulating substrate
strips including circuit components (e.g., split ring resonators)
within a slab of material are described. Briefly stated, the method
may include fixing substrate strips in a desired orientation using
one or more supports, and then filling a space enclosed by the
supports with a material that becomes solid, thus encapsulating the
substrate strips. A non-limiting example of a suitable apparatus is
illustrated in FIG. 5.
[0069] As shown, the apparatus for encapsulating substrate strips
of circuit components within a slab of material includes two
supports, labeled as support sides 502a and 502b. Though not
illustrated in FIG. 5 for purposes of simplicity, the apparatus 500
may further include further components to the supporting structure
sufficient to form a structure that can be filled with a material.
For example, further supports making up left and right ends and a
bottom surface may be included, such that the combination of
support sides 502a and 502b, together with any such left and right
ends and bottom surface may substantially form a container or
bucket-like structure having an open top. As illustrated, the
support sides 502a and 502b may include multiple slits (also
referred to herein as slots), openings, or other similar features
therein. The slits 504 may accommodate substrate strips 506a and
506b. For example, the substrate strips 506a and 506b may be
inserted into respective slits 504 in the support sides 502a and
502b.
[0070] As illustrated, the substrate strips 506a and 506b may be
substantially the same as substrate strips 306a and 306b of FIG. 3.
Thus, for purposes of simplicity, a detailed explanation of
substrate strips 506a and 506b is not now given.
[0071] Any number of substrate strips may be inserted into slits in
the support sides 502a and 502b, and in any suitable orientation.
According to non-limiting embodiment, neighboring substrate strips
may be oriented substantially at right angles with respect to each
other. However, alternative configurations are possible.
[0072] Thus, as illustrated in FIG. 5, an apparatus for forming a
slab of material having substrate strips encapsulated therein may
be configured to define a volume in which the substrate strips are
disposed. By filling the volume with an encapsulating material,
such as syntactic foam, the resulting structure may include a slab
of material in which are disposed the substrate strips 506a and
506b.
[0073] To facilitate fabrication and positioning of the substrate
strips within the resulting slab of material, fasteners 508 may be
inserted into the ends of the substrate strips 506a and 506b, for
example to prevent sliding of the substrate strip relative to the
support sides 502a and 502b of the apparatus prior to formation of
the slab of material. The fasteners may be nails, tacks, pegs, or
any other suitable fastening structures.
[0074] According to another aspect of the present application, a
method of forming substrate strips having circuits thereon within a
slab of material is described. For example, the method may
implement the apparatus 500 of FIG. 5 and may be used to form a
structure substantially similar to that illustrated in FIG. 3.
[0075] As shown, the method 600 begins at step 602 by forming
substrate strips, which may be done in any of the manners
previously described herein.
[0076] In step 604, the method continues with forming slits (or
slots) in supports. For example, slits may be formed in support
sides 502a and 502b. It should be appreciated that other types of
openings (other than slits) may alternatively be formed, and that
in some embodiments the openings need not go through the support.
For example, an indentation may be formed in a wall of a support,
and the substrate strip may be positioned to have an end within the
indentation such that is remains fixed in place.
[0077] At step 606, substrate strips may be inserted into the
supports via the slits (or other openings) formed in step 604. The
substrate strips may thus assume a fixed position relative to the
supports and with respect to each other.
[0078] In step 608, the substrate strips may be substantially
fastened relative to the support sides 502a and 502b. For example,
the substrate strips may be pinned using fasteners 508 or any other
suitable fasteners. In this manner, substrate strips may be
prevented from sliding into or out of the slits in the support
sides 502a and 502b.
[0079] In step 610, the apparatus may be filled with a suitable
material that will form into a slab. For example, "form in place
foam" may be used, though any other suitable material may
alternatively be used. In this manner, the substrate strips may be
encased within the formed slab of material.
[0080] In step 612, the supports (e.g., support sides 502a and
502b) may be removed. Thus, at this stage, the remaining product
may be a slab of material (e.g., a foam block formed of syntactic
foam) including substrate strips having circuits thereon, with ends
of the substrate strips projecting out of the slab of material.
[0081] Accordingly, in step 614, the ends of the substrate strips
may be trimmed to remove excess amounts of the strips projecting
out of the slab of material.
[0082] It should be appreciated that alternative manners to that of
method 600 for forming such structures are possible, and that the
methodology of FIG. 6 is provided as a non-limiting example.
[0083] According to another non-limiting aspect of the present
application, an electromagnetic meta-material may be formed, at
least in part, by interconnecting two or more substrates to form an
array of circuit components. In some non-limiting embodiments,
spaces between the substrates may be filled with a core material
(or filler material), though in other embodiments any spaces
between the substrates may be left as air gaps. A non-limiting
example is illustrated in FIG. 7.
[0084] As shown, the electromagnetic meta-material 700 includes a
plurality of substrates 702 which are interconnected with each
other. Each of the substrates may have one or more circuit
components 704 formed thereon. The substrates 702 may be
interconnected to form a two dimensional array, as illustrated in
FIG. 7, or to form a three dimensional array, as illustrated in
FIG. 8 and described further below.
[0085] The substrates 702 in FIG. 7 may be any suitable substrate
on which circuit components 704 may be formed. According to a
non-limiting embodiment, the substrates 702 may be any of the types
of substrates previously described with respect to the figures of
the present application. For example, substrates 702 may be the
same as previously described substrate strips 306a and 506a, though
these are non-limiting examples. Thus, as a non-limiting example,
each of substrates 702 may be formed of a printed circuit board
having a desired dielectric constant.
[0086] The substrates 702 may be interconnected in any suitable
manner. As illustrated in FIG. 7, each substrate 702 may include
slits (or slots) or notches 708 which may accommodate another one
of the substrates 702. For example, a substrate 702 having a slit
708 formed along a particular side of the substrate may be slid
down over other substrates 702 of the electromagnetic
meta-material, as illustrated by the arrows in FIG. 7. In this
manner, an array of interconnected substrates may be formed. As
illustrated, connection of the substrates 702 may effectively form
distinct unit cells 710 in which circuit components 704 are
physically separated from other circuit components of the
illustrated meta-material. The angle of intersection a between the
substrates may take any suitable value, and according to a
non-limiting embodiment is approximately 90.degree.. However, other
angles may be used.
[0087] It should be appreciated from the foregoing that the
interconnection of substrates in the manner illustrated in FIG. 7
may allow the formation of a regular, repeating pattern of circuit
components 704. Thus, a desired pattern may be formed using
suitable slits and substrates.
[0088] The circuit components 704 may be of any suitable type, and
of any suitable number. For example, circuit components 704 may be
any of those types previously described herein, for example with
respect to FIGS. 1, 3, and 5. According to a non-limiting
embodiment, each of circuit components 704 may comprise a split
ring resonator. However, other circuit components and/or circuits
may alternatively be implemented. Furthermore, each unit cell 710
need not include its own circuit component, as, for example,
circuit components may only be included on a subset of the
substrates 702 or only on certain portions of a substrate 702.
Thus, it should be appreciated that the aspect of the present
application relating to interconnection of substrates to form a
grid pattern of circuit components 704 at a desired angle of
intersection relative to each other is not limited to the number of
circuit components, the type of circuit components, or any
particular configuration of circuit components.
[0089] Optionally, interconnection of the substrates 702 may be
facilitated by a fastening mechanism, for example to ensure
rigidity of the interconnection and thus assist in the
electromagnetic meta-material 700 maintaining a desired shape. For
example, an adhesive (e.g., glue) may be placed at some or all of
the intersection points of the substrates 702.
[0090] Optionally, the spaces between the substrates 702 may be
filled with a filler material. As a non-limiting example, a
syntactic foam may be disposed within at least some of the
illustrated gaps. Not all illustrated gaps need be filled with
foam, and in some embodiments, foam is not inserted in any of the
gaps If a filler material is used, any suitable material may be
used, such as any of those previously described herein (e.g.,
filler material 116 of FIG. 1).
[0091] FIG. 8 illustrates an extension of the technology
illustrated in FIG. 7 to provide a three dimensional
electromagnetic meta-material structure. As shown, the
electromagnetic meta-material 800 includes a plurality of
structures of the type illustrated in FIG. 7, i.e., a combination
of a plurality of items 700. These may be stacked relative to each
other, with a sheet 802 between neighboring structures 700. Each of
the sheets 802 may itself optionally include a plurality of circuit
components 704 of the type previously described with respect to
FIG. 7, or any other suitable type of circuit component. As shown,
the circuit components 704 on the sheet 802 may be arranged in any
suitable manner, for example, such that a single circuit component
704 of the sheet 802 corresponds to each unit cell 710.
[0092] The sheets 802 may be formed of any suitable material, and
in some embodiments may be of the same material as that used for
substrates 702. For example, each of sheets 802 may comprise a
printed circuit board on which the circuit component 704 may be
formed in any suitable manner.
[0093] It should be appreciated that the angle which sheet 802
makes relative to the electromagnetic meta-material 700 may be any
suitable angle, such as a right angle, or any other suitable angle.
Accordingly, in a non-limiting embodiment, each unit cell 710 may
be substantially shaped as a cube. However, other configurations
are possible, as this non-limiting example is provided merely for
purposes of illustration.
[0094] The sheets 802 may be bonded relative to the electromagnetic
meta-material layer 700 in any suitable manner. For example, an
adhesive (e.g., glue) may be used.
[0095] As with the electromagnetic meta-material 700 of FIG. 7, the
unit cells 710 in FIG. 8 may be filled with a filler material, such
a syntactic foam or any other suitable type of filler material.
However, the use of such filler material in the configuration of
FIG. 8 is optional, as not all embodiments include such a filler
material.
[0096] FIG. 9 illustrates a method for fabricating the
electromagnetic meta-material of FIG. 7. The method 900 begins at
step 902 with the formation of substrates having circuit
components. Step 902 may be performed in any suitable manner,
including any of the manners previously described herein for
forming a substrate including one or more circuit components.
[0097] At step 904, slits are made along a side of at least some
substrates. In some embodiments, slits are made in all substrates,
though in other embodiments slits may only be made in a subset of
substrate. The slits may be made in any suitable manner.
[0098] In step 906, the substrates are interconnected. For example,
one substrate having slits along its side may be slid over a
plurality of other substrates, as illustrated by the arrows in FIG.
7.
[0099] Optionally, the method continues at step 908 by filling
spaces between the substrates with a filler material. Any suitable
filler material may be used, such as those previously described
herein.
[0100] The method 900 of FIG. 9 may be extended to form a
three-dimensional meta-material structure like that illustrated in
FIG. 10 by adding suitable steps for connecting the structure
resulting from method 900 to sheets 802.
[0101] Various benefits may be realized through use of one or more
of the aspects described above. For example, one or more aspects
may allow for manufacture of electromagnetic meta-materials at low
cost. One or more aspects may allow for fabrication of
electromagnetic meta-materials using relatively few fabrication
steps. One or more aspects may allow for beneficial electromagnetic
properties, for example by using materials having low dielectric
constants. Thus, signal attenuation may be minimized according to
one or more embodiments. It should be appreciated, however, that
these are non-limiting examples of benefits which may be realized,
and that additional benefits may also be realized, and likewise
that not all benefits need apply to each aspect.
[0102] The electromagnetic meta-materials according to various
aspects described herein may be used in various apparatus and
settings. For example, the meta-materials may form at least part of
an antenna, or may be used in radomes. The meta-materials may be
used to focus electromagnetic signal transmission and reception,
such as radar, which may allow for reduction in size of an antenna
using the material, as an example. Other applications are also
possible.
[0103] Having thus described several aspects of at least one
embodiment of the technology, it is to be appreciated that various
alterations, modifications, and improvements will readily occur to
those skilled in the art. For example, the steps of the illustrated
methods (e.g., the steps of FIGS. 2, 4, 6, and 9) may be rearranged
in any suitable manner. Such alterations, modifications, and
improvements are intended to be within the spirit and scope of the
technology. Accordingly, the foregoing description and drawings
provide non-limiting examples only.
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