Abstract:
A method for fabrication of electromagnetic meta-materials and structure fabricated thereby are disclosed. A substrate material is provided, and an array of electromagnetically reactive patterns of a conductive material are formed on a first face of the substrate material. An array of electromagnetically reactive patterns of a conductive material is applied to each respective face of layers of a substrate used to form a block. The substrate block is successively formed by joining each of the respective faces together such that the faces bearing the electromagnetically reactive patterns are commonly oriented. A new set of substrate layers is formed by slicing the block between elements of the array of patterns in a plane perpendicular to a face to which the electromagnetically reactive patterns were applied. After each slice is made, the slices are rotated to present a face to which magnetically conductive patterns have not yet been applied.

Description:
NOTICE OF GOVERNMENT RIGHTS  
       [0001] This invention was made with Government support under Contract MDA972-01-2-0016 awarded by DARPA. The Government has certain rights in this invention. 
     
    
     
       FIELD OF THE INVENTION  
         [0002]    This invention relates generally to a method for producing electromagnetic materials, and, more specifically, to producing electromagnetic meta-materials with selected magnetic and electric properties.  
         BACKGROUND OF THE INVENTION  
         [0003]    Conventionally, electric and magnetic fields follow what is termed as the right-hand rule: an electrical current flowing through a conductor results in a magnetic flux revolving around the conductor in a clockwise direction as observed from the direction of the source of the current. This is termed the right-hand rule because, while extending the thumb of one&#39;s right hand, the direction one&#39;s fingers curl indicates the direction in which induced magnetic flux revolves. However, as originally termed by V. G. Veselago, “left-handedness” can exist. In other words, a material can exist in which the flow of the electric current causes magnetic flux of an opposite sense, revolving in a counter-clockwise direction from the perspective of the source of the current.  
           [0004]    More specifically, conventional, right-handed materials have positive values of electric permittivity, ε, and magnetic permeability, μ. Therefore, as shown in FIG. 1, if ranges of electric permittivity and magnetic permeability are graphed in a two-dimensional Cartesian space  100 , the properties of natural materials fall in a first, upper-right quadrant  110  of the graph  100 . On the other hand, left-handed materials or meta-materials have negative values of both electric permittivity and magnetic permeability. As a result, these quantities describing left-handed materials fall in a third, lower-left quadrant  120  of the graph  100 .  
           [0005]    Left-handed materials can have useful properties in manipulating electromagnetic signals, for example, in refracting those signals. As shown in FIG. 2, an electromagnetic signal  200  passing from a first right-handed material  210  into a second right-handed material  220  at a boundary  230  will always be refracted toward the normal  240  of the boundary  230 . This is because the index of refraction n for such signals derived from Snell&#39;s law is always a positive quantity. According to Snell&#39;s law, the index of refraction n can be derived from the equation n 2 =εμ. Therefore, n={square root}{square root over (εμ)}, conventionally, necessarily yields a positive quantity. Because n is a positive quantity, as is understood by one ordinarily skilled in the art, the electromagnetic signal  200  always is refracted toward the normal  240 . However, as suggested by Veselago, if the electric permittivity ε and magnetic permeability μ are both negative numbers, then the square root of the combined quantity will yield a negative number. Thus, as shown in FIG. 3, because the index of refraction can be a negative quantity, a signal  300  passing from a right-handed material  310  into a left-handed material  320  at a boundary  330  is refracted away from the normal  340 .  
           [0006]    A material exhibiting such refractive properties, to name one example, would be useful in allowing different ways of focusing electromagnetic signal transmission and reception, such as in radar. Antennae or electromagnetic lenses incorporating left-handed materials for the transmission and reception of such signals could be shaped differently than devices constructed of only right-handed materials. However, left-handed materials are only theorized, and currently there are no methods for fabricating left-handed materials. Therefore, there is an unmet need in the art for a method to fabricate left-handed materials, as well as for the materials such a method can produce.  
         SUMMARY OF THE INVENTION  
         [0007]    The present invention provides a method for producing meta-materials whose electric permitivities and magnetic permeabilities can conform to a left-hand rule and the meta-material produced thereby. Using conventional substrates and conductive materials, layered or composite meta-materials can be constructed with controllable, desired negative values or electric permittivity and magnetic permeability. A substrate is provided on which a final product will reside or merely will support thin-layered materials during their creation. On the substrate, patterns of a conductive material are applied to create a layer of cells with the desired properties. The substrates, bearing these patterns, then can be joined together, and sliced perpendicular to the applied patterns, rotating these slices to provide a substrate for the next layer of patterns of conductive materials. This process is repeated until three dimensions of faces have had patterns of conductive material applied to them.  
           [0008]    For example, an embodiment of a method of the present invention provides a suitably conventional substrate material. An array of electromagnetically reactive patterns of a conductive material is applied to a first face of a set of substrate materials. Once the array of electromagnetically reactive patterns have been applied to the first face of a set of substrates, each of the respective substrates are joined together with or without suitable spacers between the substrates. Through this process, the faces bearing the electromagnetically reactive pattern are commonly oriented, so that each face is aligned in the same direction, thus creating a one-dimensional block of left-handed material. The substrate block is subsequently sliced between elements of the array of electromagnetically reactive patterns and in a plane perpendicular to a face to which the electromagnetically reactive patterns were applied. The slicing process creates a new set of substrates on which suitable patterns can be applied after they are rotated by ninety degrees. Again, this new set of substrates can be joined together with or without suitable spacers to form a two-dimensional block of left-handed material. This is followed by yet one more slicing process similar to the one used for the creation of the two-dimensional block. Again, suitable electromagnetic patters are applied to the ninety-degree-rotated slices, followed by a joining process to create a three-dimensional meta-material block.  
           [0009]    If desired, embodiments of the present invention also suitably involve applying a binding material to each face of the substrate, then applying the conductive patterns to the binding material. An additional layer of binding material may then be applied over the conductive patterns. The presence of the binding material allows for different presentation of the patterns of conducive material. An etching material corrosive of the substrate may be applied to formed three-dimensional meta-materials to dissolve the substrate and leave a honeycombed mass of the conductive patterns supported by a lattice of the binding material. Similarly, the binding material could be removed from the substrate and/or separated to create a plurality of cells which can be arranged in a solid form. Also, embodiments of the present invention include multi-dimensional meta-materials having electromagnetically reactive elements arrayed in at least two dimensions supported by a supporting structure.  
       
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0010]    The preferred and alternative embodiments of the present invention are described in detail below with reference to the following drawings.  
         [0011]    [0011]FIG. 1 is a prior art graph showing relative positions occupied by materials having positive and negative magnetic permeabilities and electric permativities;  
         [0012]    [0012]FIG. 2 is a prior art diagram showing refraction of an electromagnetic signal from a material observing a right-hand rule to another material observing the right-hand rule;  
         [0013]    [0013]FIG. 3 is a prior art diagram showing the refraction of an electromagnetic signal from a material observing a right-hand rule to a material observing a left-hand rule;  
         [0014]    [0014]FIG. 4A is a split ring resonator (SRR) pattern of a deposit of conductive material used in accordance with embodiments of the present invention;  
         [0015]    [0015]FIG. 4B is a square split ring resonator (SSRR) pattern of a deposit of conductive material used in accordance with embodiments of the present invention;  
         [0016]    [0016]FIG. 4C is a swiss roll (SR) pattern of a deposit of conductive material used in accordance with embodiments of the present invention  
         [0017]    [0017]FIG. 4D is a thin parallel wire (TPW pattern) of a deposit of conductive material used in accordance with embodiments of the present invention;  
         [0018]    [0018]FIG. 5 is a flowchart of a method for making meta-materials in accordance with a first embodiment of the present invention;  
         [0019]    [0019]FIG. 6A is a perspective view of patterns of conductive material applied to layers of a substrate in accordance with a first embodiment of the present invention;  
         [0020]    [0020]FIG. 6B is a perspective view of the layers of substrate bearing patterns of conductive material of FIG. 6A joined into a block;  
         [0021]    [0021]FIG. 6C is a perspective view of a slice of the block of the patterns of conductive material and substrate of FIG. 6B;  
         [0022]    [0022]FIG. 6D is a perspective view of the slice of FIG. 6B rotated clockwise ninety degrees about the Y axis;  
         [0023]    [0023]FIG. 6E is a perspective view of additional patterns of conductive material applied to slices as shown in FIG. 6D;  
         [0024]    [0024]FIG. 6F is a perspective view of the layers of substrate bearing patterns of conductive material of FIG. 6E joined into a block;  
         [0025]    [0025]FIG. 6G is a perspective view of a slice in the X-Z plane of the block of FIG. 6F rotated counterclockwise ninety degrees about the X axis;  
         [0026]    [0026]FIG. 6H is a perspective view of additional patterns of conductive material applied to slices as shown in FIG. 6G;  
         [0027]    [0027]FIG. 6I is a perspective view of the layers of substrate bearing patterns of conductive material of FIG. 6H joined into a block;  
         [0028]    [0028]FIG. 7 is a flowchart of a method for making meta-materials in accordance with a variation of the first embodiment of the present invention;  
         [0029]    [0029]FIG. 8A is a perspective view of a layer of a binding material applied over a substrate;  
         [0030]    [0030]FIG. 8B is a perspective view of patterns of conductive material applied to the layer of the binding material applied over the substrate;  
         [0031]    [0031]FIG. 8C is a perspective view of a second layer of binding material being applied over patterns of conductive material;  
         [0032]    [0032]FIG. 8D is a perspective view of a second layer of binding material in place over patterns of conductive material;  
         [0033]    [0033]FIG. 9 is a flowchart of a method for making meta-materials in accordance with a second embodiment of the present invention;  
         [0034]    [0034]FIG. 10 is an exploded perspective view of patterns of conductive material encased in layers of a binding material, a sacrificial layer, and a substrate; and  
         [0035]    [0035]FIG. 11 is a perspective view of elements comprised of individual patterns of conductive material formed on either or both faces bound together in a solid mass. 
     
    
     DETAILED DESCRIPTION OF THE INVENTION  
       [0036]    [0036]FIGS. 4A, 4B,  4 C, and  4 D show four different patterns for depositing conductive materials upon layers of substrate that may be used in the preparation of meta-materials—that is, materials exhibiting negative values of electric permittivity and magnetic permeability. The patterns, used individually or in combination in the presence of an excitation wave, can be electromagnetically reactive.  
         [0037]    [0037]FIG. 4A shows a split ring resonator pattern (SRR)  400 . The split ring resonator pattern  400  includes an inner ring  404  having a width  408  and an outer ring  412  having a width  416 . The rings  404  and  412  are separated by a gap  420 . The split ring resonator pattern  400  has an orientation  424 . Similar to the split ring resonator pattern  400  of FIG. 4A is a square split ring resonator pattern  430  (SSSR) of FIG. 4B. The square split ring resonator pattern  430  includes an inner ring  434  having a width  438  and an outer ring  442  having a width  446 . The rings  434  and  442  are separated by a gap  450 . The square split ring resonator pattern  430  has an orientation  454 .  
         [0038]    [0038]FIG. 4C shows a swiss roll pattern (SR)  460 . The swiss roll pattern  460  includes a continuous, winding loop  464  having a width  468 . The swiss roll pattern  460  has a radius  472  as measured from a centerpoint  474  to an outer edge  476 . The swiss roll pattern  460  also is described by a number of turns the loop  464  makes about the centerpoint. In the swiss roll pattern  460  shown, the loop  464  makes one and three-quarters turns about the centerpoint. The swiss roll pattern  460  has an orientation  478 .  
         [0039]    [0039]FIG. 4D shows a thin parallel wire pattern (TPW)  480 . The thin parallel wire pattern  480  is so called because the thin parallel wire pattern  480  includes a plurality of parallel wire elements  484 . Each wire element  484  of the thin parallel wire pattern  480  has a width  488  and is suitably separated from other elements  484  by a gap  492 . The thin parallel wire pattern  480  has an orientation  482 .  
         [0040]    Applying an excitation wave to one or more split ring resonator, square split ring resonator, or swiss roll patterns results in a negative effective magnetic permeability caused by the pattern&#39;s resonant reaction to the energy. On the other hand, the presence of a wire element creates a negative effective electrical permittivity in a given frequency range. Advantageously, the combination of these patterns, therefore, results in a left-handed material or meta-material in a given frequency range. For example, at a field resonance of about 4.86 gigahertz, a negative effective magnetic permeability and electric permittivity can be measured in a split ring resonator pattern having a depth of about 0.52 millimeters, an inner ring  404  having an inner radius of about 0.8 millimeters, an inner ring width  408  and an outer ring width  416  of about 1.5 millimeters, an interring gap  420  of about 0.2 millimeters, a wire thickness of about 0.4 millimeters, and a gap between a wire element  484  and the split ring resonator pattern  400  of about 0.4 millimeters. Orientation of the split ring resonator pattern  400  or other patterns relative to that of the thin wire pattern  480  is described below.  
         [0041]    Additionally, manipulating the form of these patterns can change the electromagnetic properties of devices in which they are installed. For one example, for a SRR pattern  400 , changing the width  408  of the inner loop  404 , the width  416  of the outer loop  412 , or the gap  420  between loops  404  and  412  affects the pattern&#39;s electromagnetic properties. In addition, ferromagnetic material might be inlaid inside a central area bounded by the inner loop  404  of the SRR pattern  400 , the inner loop  434  of the SSRR  430  pattern, or around the centerpoint  474  of the SR pattern  460 . Inclusion of such materials can change the magnetic permeability of the structure when exposed to a magnetic field.  
         [0042]    Making use of the patterns  400 ,  430 , and  470 , different forms of the meta-materials are created. FIG. 5 is a flowchart of a method for making meta-materials in accordance with a first embodiment of the present invention, and FIGS. 6A through 6I show perspective views of meta-materials being created thereby. The method begins at a block  504  by choosing a substrate material. The choice of substrate is open, and can be made based upon numerous design considerations to take advantage of widely different properties of each material that might prove advantageous. For example, plastics, such as Teflon, polystyrene, or polycarbonate, or ceramics, quartz, glass, polymide may be used. Having chosen the substrate at the block  504 , at a block  508  the substrate is prepared in layers. At a block  512 , any preparatory steps desired for forming a suitable spacer material, which could be the same nonconductive material chosen for the substrate or a different nonconductive material, depending on the properties desired. The properties desired can be determined based on simulation results using standard solutions of Maxwell&#39;s equations.  
         [0043]    At a block  516 , patterns of conductive materials are formed on the layers of the substrate. As will be understood by one ordinarily skilled in the art, the patterns of conductive material are suitably formed first by depositing conductive materials on the substrate layers using thin film deposition, lamination of a copper sheet, or some other technique known by those ordinarily skilled in the art. Once the conductive materials have been deposited, the material not being used is etched away using standard micro-photolithography, etching, or other techniques. The conductive material is etched away to leave patterns may include SRR patterns  400  (FIG. 4A), SSRR patterns  430  (FIG. 4B), SR patterns  460  (FIG. 4C), and/or thin parallel wire patterns  480  (FIG. 4D). Alternatively, a “direct write” technique can also be used to form the patterns.  
         [0044]    [0044]FIG. 6A is a perspective view of patterns of conductive material applied to layers of the substrate. In one embodiment, either SRR patterns  400  (FIG. 4A), SSRR patterns  430  (FIG. 4B), or SR patterns  460  (FIG. 4C) are formed on a first layer of the substrate  602 . Thin parallel wire patterns  480  (FIG. 4D) are formed on a second layer of the substrate  604 . Then, alternating, either SRR patterns  400  (FIG. 4A), SSRR patterns  430  (FIG. 4B), or SR patterns  460  (FIG. 4C) are formed on a third layer of the substrate  606 , and so on. On the first layer of substrate  602  and the third layer of the substrate  606 , patterns  608  of conductive material, whether SRR patterns  400  (FIG. 4A), SSRR patterns  430  (FIG. 4B), or SR patterns  460  (FIG. 4C), are depicted only by their orientation,  424 ,  454 , and  478  (FIGS. 4A, 4B,  4 C), respectively, for the sake of visual simplicity in FIGS.  6 A through FIG. 6I. On the second layer of substrate  604 , elements  610  of the thin parallel wire pattern  480  (FIG. 4D) are shown as they would be oriented. On the third layer of substrate  606 , additional patterns  608  of conductive material are formed in the same orientation as used on the first layer  602 .  
         [0045]    In another embodiment not shown, at the block  516  either SRR patterns  400  (FIG. 4A), SSRR patterns  430  (FIG. 4B), or SR patterns  460  (FIG. 4C) are formed one a first side of a substrate layer and thin parallel wire patterns  480  (FIG. 4D) are formed on a second side of the same substrate layer, forming double-sided layers. After the conductive patterns are formed, blank spacer layers are inserted between the double-sided layers. The blank spacer layers are composed of a nonconducting material which can be the same as the substrate layers or a different material. The presence of the blank spacer layers is to adjust an effective dielectric constant of a resulting composite structure, thereby changing a frequency and a bandwidth of a left-handed pass band.  
         [0046]    Returning now to FIG. 5, at a block  520  alternating layers of the substrate  602 ,  604 , and  606  (FIG. 6A) bearing the conductive patterns are attached together to form a block  612 , as shown in FIG. 6B. In a process known to one ordinarily skilled in the art, the layers of the substrate are joined using a glue material (not shown) having material properties similar to those of the chosen substrate and/or spacer layer. For example, to attach layers of substrate consisting of polymide, liquid polymnide could be used. Similarly, for Teflon substrates, a liquid Teflon or laminate Teflon material can be used, or a liquid polystyrene could be used for polystyrene substrates. The object is to choose a glue material having as close as possible to the same chemical and physical composition as the substrate itself to create a largely homogenous block  612 .  
         [0047]    Alternatively, if quartz or glass is used as the substrate, standard bonding techniques suitably are used. Such standard bonding techniques rely on the creation of surface charged layers that do not require the use of a glue or adhesive. In addition, instead of bonding layers to each other, an encapsulating material transparent to incident electromagnetic fields suitably may be used to hold the layers together.  
         [0048]    In any case, an object in a method for joining the layers is to avoid thermal expansion mismatches and similar problems that could result if the physical properties of a glue material or encapsulating material did not match that of the substrate itself. The attachment process itself will be achieved by curing the stacked and glued imprinted layers of the substrate to create the solid block  612 . As shown in FIG. 6B, ends of the thin parallel wire pattern elements  610  can be engaged at edges of the block  612 .  
         [0049]    At a block  524 , to prepare layers for creation of the next set of patterns of conductive materials, the block  612  formed at the block  520  is sliced. Slices are made between the patterns  608  and the thin parallel wire elements in a Y-Z plane (according to the perspective of FIG. 6B) where the layers are stacked along a Z axis and the thin parallel wire elements  610  and the other elements  608  extend parallel to a Y axis. Referring to FIG. 6C, the resulting slices have an appearance of a slice  614 . In the slice  614 , segments of the substrate layers  602 ,  604 , and  606  are still visible, as are the patterns  608  of the conductive materials formed on the third layer  606  and the ends of the thin parallel wire elements  610 .  
         [0050]    Once the slices  614  have been created at the block  524  (FIG. 5), at a block  528  each of the slices is rotated to present a layer for the formation of the next group of patterns of conductive material. As described at the block  528  and shown in FIG. 6D, each of the slices formed at block  524  are rotated about the Y axis to present the next face to be used for the formation of conductive patterns. FIG. 6D shows, as can be seen from the relative positions of segments of layers  602 ,  604 , and  606 , the conductive patterns  608 , and the thin parallel wire elements  610 , that the slice  614  of FIG. 6C has been rotated ninety degrees clockwise about the Y axis. As also can be seen in FIG. 6D, this rotation of the slice  614  presents a clean face for formation of another set of conductive patterns.  
         [0051]    Beginning with a block  532  of FIG. 5, the process represented by blocks  512  through  528  now largely repeats with regard to the layers formed in the preceding steps with a few differences, as will be explained. At the block  532 , the second layers, which include slices formed and rotated such as the slice  614  of FIG. 6D, are prepared for the deposition of conductive materials using known means. At a block  536 , using the same methods previously described in connection with block  516 , conductive materials are deposited and then etched to form conductive patterns. As shown in FIG. 6E, these patterns are formed on layers such as the slice  614 , shown in FIG. 6D, and similar layers  616  and  618 . Alternatively, the thin parallel wire patterns  622  suitably are formed on a second face of the layers  614  and  618 , and the layer  616  can be replaced by a blank spacer layer.  
         [0052]    [0052]FIG. 6E shows a difference between the blocks  516  and  536  in the orientation of the conductive patterns formed. The SRR patterns  400  (FIG. 4A), SSRR patterns  430  (FIG. 4B), or the SR patterns  460  (FIG. 4C) are now oriented as shown by the double arrows  620  shown in FIG. 6E, representing the patterns. As one views FIG. 6E, this orientation is parallel to an X axis and directed from right to left, or directed from a conventional positive value of an X variable toward a conventionally negative value of X. Second thin parallel wire element patterns  622  are aligned parallel with the alignment of the patterns  620 . As one can see from FIG. 6E, the newly-formed patterns  620  and  622  run perpendicular to the first formed patterns  608  and  610 .  
         [0053]    At a block  540  (FIG. 5), the imprinted layers  614 ,  616 , and  618  are now joined into a block  624 , using a process like that described in connection with step  520 . The block formed is shown in FIG. 6F. Also, comparable with the process described at block  524 , at a block  544  the block  624  is now sliced to form layers to be used for the further imprinting of conductive patterns. A difference between the blocks  524  and  544 , comparable to the difference between the deposition blocks of  516  and  536 , is one of orientation. At the block  544 , the block  624  is sliced to form new layers. The difference between the blocks  524  and  544  is that the conductive patterns formed at block  536  run parallel to an X-axis, while those that are formed at the block  516  run parallel to the Y-axis. Thus, the slices are made in an X-Z plane. The resulting slice is then rotated about its X-axis to form a slice  626  shown in FIG. 6G. The slice  626  shows a blank surface  628 , ready to be imprinted with conductive patterns. Although the slice  626  has the remaining blank surface  628 , it will be appreciated that, perpendicular to an X-Y plane containing the surface  628  are patterns  608  and  610 , and parallel to that plane are patterns  620  and  622 .  
         [0054]    A last phase of the process begins at a block  552  (FIG. 5) in which layers are again prepared, as previously referenced, for the deposition of conductive materials. At a block  556 , conductive patterns are formed on these layers through the deposition and etching process previously described in connection with the blocks  516  and  536 . Again, a difference is one of orientation. As shown in FIG. 6H, a third grouping of conductive patterns, SRR patterns  400  (FIG. 4A), SSRR patterns  430  (FIG. 4B), or SR patterns  460  (FIG. 4C) are formed, oriented as shown by the triple arrows  630  shown in FIG. 6H, representing the patterns. The orientation is directed along the Y-axis. Thin parallel wire pattern elements  632  are also oriented as shown, parallel with the Y-axis. Comparable with steps at the blocks  520  and  540  (FIG. 5), at a block  560  imprinted layers are now joined, as shown in FIG. 6I, into a block  634 . This block now represents a completed unit of three-dimensional meta-material.  
         [0055]    A variation of the first embodiment of a method for making meta-materials is described in FIG. 7, and FIGS. 8A through 8D show perspective views of meta-materials being created thereby. An object of this variation is creating a similar structure supporting a plurality of conductive patterns, but in a manner in which the underlying substrate can be removed to create a resulting structure having reduced weight. To this end, conductive patterns are formed not on the substrate directly, but on layers of a binding material or binder applied to the layers of substrate, with the layers of substrate material subsequently being etched away or otherwise removed. Many of the steps are similar to steps  505  through  560  as shown in FIG. 5. In the interest of brevity, details of comparable steps will not be repeated, but differences will be highlighted.  
         [0056]    The method begins at a block  704  by choosing a substrate material. The material that is selected for the substrate is suitably a material that can be etched away without disturbing the integrity of the binder, which is explained below. For example, the substrate may be aluminum-based so that it can be dissolved with a weak acid that will not dissolve the binder. Having chosen the substrate at the block  704 , at a block  708  the chosen substrate is prepared in layers. At a block  712 , any preparatory steps desired for the application of materials to the substrate completed.  
         [0057]    At a block  714 , the binder is applied to the substrate. The binder may be a thermoplastic, an organic resin, or other material that, in contrast to the substrate material, suitably withstands corrosive effects of the etching material. FIG. 8A is a perspective view representing a layer of the binder  802  being applied to a layer of the substrate  804 . At a block  716  (FIG. 7), patterns of conductive materials are then formed on the layer of binder instead of directly on the substrate. FIG. 8B is a perspective view of the substrate layer  802  applied to the substrate layer  804  with a plurality of conductive patterns  808  applied to the binding layer  802 . In FIG. 8B, the patterns of the conductive material as shown in FIGS. 4A through 4C for the sake of visual simplicity are represented by a single arrow indicating their orientation.  
         [0058]    At a block  718 , a second layer of a binder is applied over the patterns of conductive material. The second layer of binder may be useful to protect the patterns of conductive material, to serve as additional binder in joining the layers as will be described below, or for other purposes. FIG. 8C shows the second layer of binder  810  in the process of being applied over the conductive patterns  808 . FIG. 8D shows the second layer  810  in place over the conductive patterns  808 . The two layers of binder  802  and  810  effectively seal the conductive patterns in the selected binding material. At a block  719 , access holes are then formed in the binder for the purpose of allowing etchant to more easily reach the substrate material when the substrate is subsequently removed. Accordingly, the access holes suitably extend completely through the thickness of the layers of binder to the substrate. Such access holes can be formed by chemical etching, reactive ion etching (RIE), laser drilling, or the like. The access holes may be formed away from the patterns of conductive material to ensure the patterns are not damaged during the formation of the access holes.  
         [0059]    At a block  720 , alternating layers of the substrate bearing the conductive patterns are attached together to form a block as was done at the block  520  (FIG. 5) and as shown in FIG. 6B. The binder chosen to form the layers may serve as the glue to join the layers, or an additional gluing material can be used as desired. At a block  724 , to prepare layers for creation of the next set of patterns of conductive materials, the block formed in the block  720  is sliced. Slices are made between the conductive patterns in a Y-Z plane. At a block  728 , each of the slices is rotated about the Y-axis to present a layer for formation of a next group of patterns of conductive material.  
         [0060]    Beginning with a block  732 , the process represented by blocks  712  through  728  now largely repeats with regard to the layers formed in the preceding blocks with a few differences. At the block  732 , the second layers, which include the slices formed and rotated during the preceding steps, are prepared for the deposition of materials using known methods. At a block  734 , a binder is applied to the second layers. At a block  736  conductive materials are deposited and then etched to form conductive patterns. The relative orientation of each of these series of conductive patterns is suitably similar to that shown in FIGS. 6A through 6I. At a block  738 , a second layer of binder is applied over the conductive patterns. At a block  739 , access holes are formed in the layers of the binder. At a block  740  the layers are joined into a block. At a block  744 , the block is now sliced to form layers to be used for the further imprinting of conductive patterns. The difference between the blocks  724  and  744 , like those steps illustrated in FIGS. 6A through 6I, is that the conductive patterns formed at block  736  run parallel to an X-axis. Thus, the slices are made in an X-Z plane. A resulting slice is then rotated about its X-axis to form a slice ready to be layered with binder and imprinted with conductive patterns.  
         [0061]    The last phase of the process begins at a block  752  in which layers are again prepared, as previously referenced, for the deposition of materials. At a block  754 , a binder layer is applied. At a block  756 , conductive patterns are formed on the layers of binder. Again, a difference is one of orientation, as previously described in connection with FIGS. 6A through 6I. At a block  758 , a second layer of binder is applied over the conductive patterns. At a block  759 , access holes are formed in the layers of binder. Comparable with steps  720  and  740  (FIG. 7), at a block  760  imprinted layers are now joined.  
         [0062]    However, as opposed to the process described in connection with FIG. 5, the process described in FIG. 7 is not yet completed. At a block  764 , an etchant is now applied to dissolve the substrate. The resulting structure of conductive patterns is suitably the same, but in this variation the conductive patterns are now supported in a honeycombed lattice of layers of binder, without the mass of the substrate material. This honeycombed lattice now represents a completed unit of meta-material according to a variation of the first embodiment of the invention.  
         [0063]    A second embodiment of the method of the present invention is described in FIG. 9 with arrangement of materials used in the method illustrated in an exploded perspective view of FIG. 10. An object of this second embodiment is to form elements of conductive patterns which may be arranged in ways other than the blocks formed according to the method shown in FIG. 5 or the lattice formed according to the method shown in FIG. 7. In short, conductive patterns are formed in a binder matrix similar to that previously described in FIG. 7. However, in this embodiment, the individual patterns are formed and separated by etching, and then the binder-encased patterns are removed from the substrate for arrangement and installation. The process of the second embodiment does not involve the joining, slicing, and/or rotating of layers as described in the preceding methods of FIGS. 5 and 7.  
         [0064]    A process of the second embodiment begins at a block  904  with the selection of a substrate material. The substrate in this embodiment may advantageously be reusable for creating multiple batches of conductive patterns. Accordingly, the substrate material can be chosen for its durability and resilience to chemicals. At a block  908 , a sacrificial material is chosen, and the sacrificial material is applied to the substrate at a block  912 . The sacrificial material is suitably a dissolvable material which can be etched away to free from the substrate materials applied to the sacrificial layer, as will be explained below. Once the sacrificial layer has been deposited on the substrate at block  912 , a first layer of a binder is applied to the sacrificial layer at a block  916 . At a block  920 , conductive patterns are formed on the first layer of binder using one of the methods previously described. At a block  924 , a second layer of binder is applied over the conductive patterns, also as previously described.  
         [0065]    [0065]FIG. 10 shows the sacrificial layer  1002  as it will be applied to a substrate  1004  beneath a first layer of a binding material  1010 . Patterns of conductive material  1008  are applied to the first layer of binder  1010 , and the second layer of the binder  1012  is applied over the patterns of conductive material  1008 .  
         [0066]    Once the layers shownin FIG. 10 have all been formed upon the substrate  1004 , the binder supporting the cells comprised of binder material  1010  and  1012  and patterns of conductive material  1008  is scored at a block  926  to separate the cells from one another. The cells are then freed from the substrate at a block  928  (FIG. 9). The cells can be freed in a number of ways. For one non-limiting example, the sheets of binder  1010  and  1012  encasing a plurality of patterns of conductive material can be freed by applying an etchant to dissolve the sacrificial layer. This frees the first layer of binding material  1010  from the substrate, leaving the binder layers  1010  and  1012  encasing the patterns of conductive material. The layers  1010  and  1012  can then be sliced between the patterns of conductive materials to create individual cells. For a second non-limiting example, the layers of binder  1010  and  1012  and the sacrificial layer  1002  are suitably etched away between the conductive patterns  1008 . Subsequently, another etchant corrosive to the sacrificial layer  1002  is suitably applied to free the cells.  
         [0067]    Once the cells are freed, they can be arranged in a number of ways as desired. FIG. 11 shows an amorphous arrangement of individual cells  1100 . The cells  1100  can be joined in a mass  1102  with a binding material (not shown) in a common orientation as shown, or in a more random arrangement. Wire elements  1104  can be arrayed near or within the mass to engage the cells  1100 . A structure similar to the foregoing amorphous arrangement of cells is achievable by forming a split ring resonator pattern  400  (FIG. 4A), a square split ring resonator pattern  430  (FIG. 4B), or a swiss roll pattern  460  (FIG. 4C) on one side of a substrate and a thin wire pattern  484  (FIG. 4D) can be formed on an opposite side of the substrate such that separate wire elements  1104  need not be included.  
         [0068]    While the preferred embodiment of the invention has been illustrated and described, as noted above, many changes can be made without departing from the spirit and scope of the invention. Accordingly, the scope of the invention is not limited by the disclosure of the preferred embodiment. Instead, the invention should be determined entirely by reference to the claims that follow.