Method for producing spatially varying dielectric material, article produced by the method, and use thereof

Abstract

To provide a method for producing a polymer structure having spatially gradient dielectric constant.SOLUTION: A stereolithography method includes the steps of: providing a quantity of a liquid radiation curable composition; exposing a portion of the liquid radiation curable composition to activating radiation in a pattern to form a layer of a polymeric structure; contacting the layer with a liquid radiation curable composition; exposing the liquid radiation curable composition to activating radiation in a pattern to form a second layer on a first layer; and repeating the contacting and irradiating steps to form a polymer structure. The polymer structure includes a plurality of unit cells, each unit cell integrally connected to an adjacent unit cell and defined by a plurality of trusses formed by the irradiating step, the trusses of each unit cell being dimensioned to provide a spatially gradient dielectric constant.SELECTED DRAWING: Figure 8

Description

[Technical field]

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS This application claims priority to and the benefit of U.S. Provisional Application No. 62 / 747,497, filed October 18, 2018, which is incorporated herein by reference in its entirety.

[0002] Disclosed herein are methods for additive manufacturing production of structures having spatially varying dielectric constants, electronic devices made by the methods, and uses of the electronic devices in electronic articles. [Background technology]

[0003] A number of dielectric structures with preselected dielectric constants have been described for use in electronic devices. Methods for the fabrication of structures with spatially varying dielectric constants, such as Luneburg lenses, are a more difficult problem to solve. One way to approach the fabrication of structures such as Luneburg lenses is to spatially vary the density of the dielectric material, which results in a corresponding spatial variation in the dielectric constant. For example, U.S. Pat. No. 5,677,796 describes a Luneburg lens with a dielectric gradient formed by drilling multiple holes extending radially from the center of a sphere to control the local density of the resulting material, and therefore the relative dielectric constant, as a function of distance from the center of the sphere. U.S. Pat. No. 7,179,844 describes the three-dimensional expansion of three different composites providing three different materials with uniform but different dielectric constants, and then layering these materials to provide a structure with a step gradient in dielectric constant. These methods are slow, complex, and difficult to adapt to different shapes and different gradients.

[0004] Additive manufacturing (AM), which includes three-dimensional (3D) printing and solid freeform fabrication, allows the production of three-dimensional objects of virtually any shape from digital models. Typically, this is accomplished by creating a digital blueprint of the desired structure in computer-aided design (CAD) modeling software and then slicing that virtual blueprint into digital cross sections. These cross sections are formed or deposited in a sequential layering process to create the 3D structure. Liang et al. describe an additive manufacturing (AM) method to create structures with a step gradient in dielectric constant (Liang, M et al., "A 3-D Luneburg lens antenna fabricated by polymer jetting rapid prototyping," IEEE Transactions on Antennas and Propagation, 62(4), 1799-1807). Liang et al. describe a polymer jetting process, similar to an ink jetting process, in which thin layers of two different radiation curable compositions, one for the object and one for the support material, are jetted onto a stage and cured. This polymer jetting process allows the production of small structures of various overall shapes. However, the geometries are limited in that there cannot be overhangs unless a support material is simultaneously deposited and then removed. The process is further limited with respect to the type of polymer used, because the polymer must be jettable in very fine streams while at the same time providing the desired mechanical and electrical properties upon curing. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] U.S. Patent No. 5,677,796 [Patent Document 2] U.S. Patent No. 7,179,844 [Patent Document 3] U.S. Patent No. 4,575,330 [Patent Document 4] U.S. Patent No. 4,929,402 [Patent Document 5] U.S. Patent No. 5,104,592 [Patent Document 6] U.S. Patent No. 5,184,307 [Patent Document 7] U.S. Patent No. 5,192,559 [Patent Document 8] U.S. Patent No. 5,234,636 [Patent Document 9] U.S. Patent No. 5,236,637 [Patent Document 10] U.S. Patent No. 5,273,691 [Patent Document 11] WO2014 / 126837 [Patent Document 12] WO2016 / 153711 [Patent Document 13] U.S. Patent No. 8,232,043 [Patent Document 14] U.S. Patent No. 8,119,214 [Patent Document 15] U.S. Patent No. 7,935,476 [Patent Document 16] U.S. Patent No. 7,767,728 [Patent Document 17] U.S. Patent No. 7,649,029 [Patent Document 18] WO2012 / 129968 [Patent Document 19] CN102715751 [Patent Document 20] Patent Publication No. 2012-210408 [Patent Document 21] U.S. Patent No. 7,824,839 [Patent Document 22] U.S. Patent No. 7,550,246 [Patent Document 23] U.S. Patent No. 7,534,844 [Patent Document 24] WO2017 / 040883 [Patent Document 25] U.S. Patent No. 9,205,601 [Patent Document 26] WO2017 / 040 [Non-patent literature]

[0006] [Non-Patent Document 1] Liang, M et al., "A 3-D Luneburg lens antenna fabricated by polymer jetting rapid prototyping," IEEE Transactions on Antennas and Propagation, 62(4), 1799~1807 [Non-Patent Document 2] "Photoacid Generator Selection Guide for the electronics industry and energy curable coatings", BASF 2010 Summary of the Invention [Problem to be solved by the invention]

[0007] Thus, there remains a need in the art for efficient and flexible methods for the fabrication of dielectric polymer structures in which the dielectric constant varies spatially across the material. [Means for solving the problem]

[0008] Disclosed herein is a method for the fabrication of a polymer structure having a spatially gradient dielectric constant, the method comprising the steps of providing a volume of a liquid radiation curable composition, irradiating a portion of the liquid radiation curable composition with activating radiation in a pattern to form a layer of a polymer structure, contacting the layer with the liquid radiation curable composition, irradiating the liquid radiation curable composition with activating radiation in a pattern to form a second layer on the first layer, and repeating the contacting and irradiating to form a polymer structure, the polymer structure comprising a plurality of unit cells, each unit cell integrally connected to adjacent unit cells, each unit cell defined by a plurality of trusses formed by the irradiation, the trusses being integrally connected to one another at their respective ends, the trusses of each unit cell being dimensioned to provide the spatially gradient dielectric constant.

[0009] Also disclosed are polymer structures made by the above methods.

[0010] In another aspect, an electronic device comprises a polymer structure, the polymer structure comprising a body of dielectric material including a plurality of unit cells, each unit cell including a plurality of trusses integrally connected to one another at their respective ends, each unit cell being integrally connected to an adjacent one of the unit cells, and an average dielectric constant of the body of dielectric material varies from a first portion of the body to a second portion of the body.

[0011] Also described are electronic devices including polymer structures in which the body of dielectric material forms at least a portion of an impedance matching layer, a dielectric waveguide, a lens, a reflector array, an antenna matching structure, a superstrate, a coupler, a frequency divider, or a dielectric antenna.

[0012] The above and other features are illustrated by the following figures, detailed description, examples, and claims.

[0013] The following figures are exemplary embodiments, which are provided to illustrate aspects of the present disclosure. [Brief description of the drawings]

[0014] [Figure 1A] FIG. 1 is a schematic perspective view of a cubic lattice unit cell of a polymer structure. [Figure 1B] FIG. 1B is a schematic perspective view of a polymer structure comprising multiple cubic lattice unit cells as shown in FIG. 1A. [Figure 2A] FIG. 1 is a schematic perspective view of an octet lattice unit cell of a polymer structure. [Figure 2B] FIG. 2B is a schematic perspective view of a polymer structure including multiple octet lattice unit cells as shown in FIG. 2A. [Figure 3A] FIG. 2 is a schematic cross-sectional view of an exemplary embodiment of a truss; [Figure 3B] FIG. 2 is a schematic cross-sectional view of an exemplary embodiment of a truss; [Figure 3C] FIG. 1 is a schematic cross-sectional view of an exemplary embodiment of a truss; [Figure 3D] FIG. 1 is a schematic cross-sectional view of an exemplary embodiment of a truss; [Figure 3E] FIG. 1 is a schematic cross-sectional view of an exemplary embodiment of a truss; [Figure 3F] FIG. 1 is a schematic cross-sectional view of an exemplary embodiment of a truss; [Figure 4A] FIG. 1 is a schematic side view of an exemplary embodiment of a truss; [Figure 4B] FIG. 1 is a schematic side view of an exemplary embodiment of a truss; [Figure 4C] FIG. 1 is a schematic side view of an exemplary embodiment of a truss; [Figure 4D] FIG. 1 is a schematic side view of an exemplary embodiment of a truss; [Diagram 5] 1 is a graph showing Dk versus truss diameter for an octet unit cell. [Figure 6A] 1 is a schematic diagram of the shape of a polymeric structure of an exemplary embodiment. [Figure 6B] 1 is a schematic diagram of the shape of a polymeric structure of an exemplary embodiment. [Figure 6C] 1 is a schematic diagram of the shape of a polymeric structure of an exemplary embodiment. [Figure 6D] 1 is a schematic diagram of the shape of a polymeric structure of an exemplary embodiment. [Figure 6E] 1 is a schematic diagram of the shape of a polymeric structure of an exemplary embodiment. [Figure 6F] 1 is a schematic diagram of the shape of a polymeric structure of an exemplary embodiment. [Figure 6G] 1 is a schematic diagram of the shape of a polymeric structure of an exemplary embodiment. [Figure 6H] 1 is a schematic diagram of the shape of a polymeric structure of an exemplary embodiment. [Figure 6I] 1 is a schematic diagram of the shape of a polymeric structure of an exemplary embodiment. [Figure 6J] 1 is a schematic diagram of the shape of a polymeric structure of an exemplary embodiment. [Figure 7A] 1 is a schematic cross-sectional view of a polymer shape according to an exemplary embodiment. [Figure 7B] 1 is a schematic cross-sectional view of a polymer shape according to an exemplary embodiment. [Figure 7C] 1 is a schematic cross-sectional view of a polymer shape according to an exemplary embodiment. [Figure 7D] 1 is a schematic cross-sectional view of a polymer shape according to an exemplary embodiment. [Figure 7E] 1 is a schematic cross-sectional view of a polymer shape according to an exemplary embodiment. [Figure 8] FIG. 1 is a schematic perspective view of a polymer structure having a step gradient dielectric constant that increases in the X direction with an increase in truss diameter in the X direction. [Figure 9] FIG. 1 is a schematic perspective view of a polymer structure having a continuous gradient dielectric constant that increases in the X direction with an increase in the truss diameter in the X direction. [Figure 10A] FIG. 2 is a schematic diagram of a dielectric gradient in a polymer structure according to an exemplary embodiment. [Figure 10B] FIG. 2 is a schematic diagram of a dielectric gradient in a polymer structure according to an exemplary embodiment. [Figure 10C] FIG. 2 is a schematic diagram of a dielectric gradient in a polymer structure according to an exemplary embodiment. [Figure 10D] FIG. 2 is a schematic diagram of a dielectric gradient in a polymer structure according to an exemplary embodiment. [Figure 10E] FIG. 2 is a schematic diagram of a dielectric gradient in a polymer structure according to an exemplary embodiment. [Figure 10F] FIG. 2 is a schematic diagram of a dielectric gradient in a polymer structure according to an exemplary embodiment. [Figure 11] FIG. 1 illustrates an electronic structure or device, in particular an electromagnetic structure or device, according to one embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0015] It has been discovered by the inventors that stereolithography (SLA) additive manufacturing can be used to efficiently obtain polymer structures with varying dielectric constants across the polymer material. In particular, the SLA method can be used to provide polymer structures with open lattice cell structures, where the size of each lattice is varied to provide a corresponding change in dielectric constant. This method allows for rapid and efficient fabrication of structures with preselected dielectric constant gradients in a variety of configurations and shapes. This method is also suitable for the use of different polymers and polymer compositions. Polymer structures useful in 5G applications can be produced.

[0016] SLA is also known in the art as photofabrication, photosetting, and resin printing. Any of the above methods may be used herein and collectively referred to as "SLA" methods. In these methods, successive thin layers of liquid resin are selectively photopolymerized using a light source, starting from the bottom layer to the top layer, or starting from the top layer to the lower layer. This process is described, for example, in U.S. Pat. No. 4,575,330, U.S. Pat. No. 4,929,402, U.S. Pat. No. 5,104,592, U.S. Pat. No. 5,184,307, U.S. Pat. No. 5,192,559, U.S. Pat. No. 5,234,636, U.S. Pat. No. 5,236,637, and U.S. Pat. No. 5,273,691.

[0017] There are different approaches to SLA, including direct / laser writing and mask-based writing with digital projection. In direct / laser writing, the stage on which the polymer material is formed is placed just below the surface of the volume of curable liquid resin composition for the formation of the polymer. A single light source (e.g., a laser) moves line by line along the surface of the curable composition until it has fully cured the desired layer. To start the next layer, the stage sinks lower into the volume of the curable liquid resin composition until a new layer of curable composition covers the surface and the curing process is repeated. Between layers, a blade loaded with the curable liquid resin composition flattens the surface of the resin to ensure a uniform layer of liquid before the next round of exposure. This procedure is repeated until the curable liquid resin composition is printed to form the 3D structure.

[0018] In mask-based writing using digital projection, a stage is lowered a defined distance into a volume of liquid curable composition. This volume is placed in a bath with an optically transparent bottom. A light source is then directed to the stage in a pattern to polymerize the curable composition between the light source and the stage. In the digital projection method, a digital mirror device allows the entire layer of a given pattern to be cured simultaneously. The stage can then be raised a defined distance and the other layers can be cured. This procedure is repeated until the curable liquid resin composition is printed to form a 3D structure.

[0019] The polymer structure formed by SLA is a unity of dielectric material that includes a plurality of unit cells. Each unit cell includes a plurality of trusses that are integrally connected to one another at their respective ends. Each unit cell is integrally connected to an adjacent one of the unit cells. The average dielectric constant of the unity of dielectric material varies from one portion of the unity to another portion of the unity. For example, the average dielectric constant of the unity of dielectric material may vary from an inner portion to an outer portion of the unity or from one side of the unity to the other side of the unity.

[0020] In particular, the unit cells include trusses that define void spaces, as shown, for example, in FIGS. 1A and 1B. FIG. 1A shows a cubic unit cell 10 that includes trusses 12 that define void spaces 13. FIG. 2A shows an octet unit cell 20 that includes trusses and void spaces defined by these trusses. As used herein, the term "truss" refers to a structural member of a framework of members, with each truss member connected only at its respective end 14 to other adjacent truss members to form joints between the truss ends, as shown by the spheres 14. Any loads distributed through each truss member are assumed to be distributed through the corresponding joints 14. It should be understood that the spheres shown at the joints 14 are only for illustration of the joints and may or may not be present in the polymer lattice structure. In one embodiment, there is no additional material at the joints of the polymer lattice structure, except for the material provided by each truss that forms the joint.

[0021] Each truss 12 may be straight or curved. In one embodiment, each truss is substantially straight. Each truss may have an irregular or substantially regular cross section. For example, with reference to Figures 3B-3F, the cross section may be circular (Figure 3A), elliptical (Figure 3B), polygonal, e.g., hexagonal (Figure 3C) or rectangular (3D), ring (Figure 3E), oval (Figure 3F), etc. In one embodiment, each truss is of the same cross section throughout the length of the truss, such as circular or square. Alternatively, it is possible to have a truss that varies in cross section, e.g., substantially circular at each end, but substantially square in the portion between each end. Each truss within a unit cell may further have the same cross-sectional diameter or different diameters. For example, while each truss 12 in Fig. 2A is shown as having a substantially uniform diameter throughout its length, with reference to Figs. 4A-4D, each truss can also have a diameter that varies along its length, such as a dog bone shape with a larger circular diameter at each of its ends (Fig. 4A), or a pyramid (Fig. 4B) or polygonal shape (4C) with a larger diameter at each of its ends. In some embodiments, particularly when a continuous gradient is desired as described in more detail below, the truss can have a continuously varying diameter from one end to the other, i.e., from smaller to larger where H1 is less than H2 (Fig. 4D).

[0022] Each truss may have a diameter ranging from 0.03 to 5.0 millimeters (mm), preferably 0.05 to 4.0 mm. As used herein, "diameter" refers to the average maximum cross-sectional dimension. If the trusses have a substantially constant diameter, the average diameter may range from 0.03 to 5.0, preferably 0.05 to 4.0. If the trusses have a continuously varying diameter, the trusses may vary within this range, e.g., 0.03 to 1.0 mm, 1.0 to 1.7 mm, 1.7 to 2.4 mm, etc.

[0023] The unit cell can be of any lattice configuration, such as a cube (FIG. 1A) and its variants, such as body-centered or face-centered cube, or an octet (FIG. 2A). The use of an octet lattice unit cell is preferred because it allows for thinner truss diameters and lengths that can be easily scaled to higher frequencies. Octet lattice units are also advantageous because they can have an isotropic dielectric constant within the unit, allowing a given electromagnetic wave to interact with the unit in the same way regardless of its orientation. A simulation predicting the dielectric constant (Dk) versus truss diameter in millimeters is shown in FIG. 5.

[0024] Each of the unit cells can have a size less than 30%, or less than 20%, or less than 10% of the wavelength of the electromagnetic wave that the polymer structure is designed to operate at. The wavelength of the electromagnetic wave is limited primarily by manufacturing capabilities and therefore can vary widely. In one embodiment, the frequency range of operation is 1 to 100 GHz, i.e., wavelengths of 3 to 300 mm. The smallest cell size (e.g., 1 mm) may currently be limited by current manufacturing capabilities.

[0025] As shown in Figures 1B and 2B, the polymer structure is a unitary three-dimensional body that includes a plurality of unit cells, each cell being adjacent to the other cells. In one embodiment, each unit cell is integrally connected to a neighboring one of the unit cells. For example, the polymer structure 20 in Figure 1B includes eight unit cells 10. Although the polymer structures in Figures 1B and 2B are shown as a cube and an irregular shape, respectively, any shape can be used. Now referring to Figures 6A-6J, any of the dielectric structures 20 disclosed herein can have a three-dimensional form in the shape of a cylinder (Figure 6A), a polygonal box (Figure 6B), a tapered polygonal box (Figure 6C), a cone (Figure 6D), a cube (Figure 6E), a truncated cone (Figure 6F), a square pyramid (Figure 6G), a toroid (Figure 6H), a dome (Figure 6I), an elongated dome (Figure 6J), or any other three-dimensional form suitable for the purposes disclosed herein. 7A-7E, such shapes can have a z-axis cross-section that is circular (FIG. 7A), polygonal (FIG. 7B), rectangular (FIG. 7C), ring (FIG. 7D), elliptical (FIG. 7E), or any other shape suitable for the purposes disclosed herein. Additionally, the shape can depend on the polymer used, the desired dielectric gradient, the selected type of unit cell, and the desired mechanical and electrical properties.

[0026] A dielectric gradient in a polymer structure is established by varying the density of each unit cell, or more generally, the density of a selected set of unit cells. Density can be varied by including more material in each unit cell, with more material providing a higher dielectric constant and less material providing a lower dielectric constant. For example, as disclosed in Liang et al., referenced above, each set of unit cells in a layer can include additional polymer deposited at the junctions of the unit cells.

[0027] In a preferred embodiment, the density of the polymer structure is varied by varying the diameter of each truss in a selected set of unit cells. Referring to FIG. 8, the polymer structure 20 includes three sets of unit cells 10a, 10b, and 10c in the X direction. The diameter of each truss in each of the sets of unit cells 10a, 10b, and 10c increases in thickness in the X direction, decreasing the size of the gaps 13a, 13b, and 13c in each of the unit cells 10a, 10b, and 10c, respectively. When these gaps are filled with air, a step gradient from low (set 10a) to high (set 10c) dielectric constant is provided.

[0028] In other embodiments, the diameter of each truss of the unit cells can vary within the set of cells to provide a continuous gradient. For example, as shown in FIG. 9, truss 12a (a horizontal truss) along the X direction of set 10a increases in diameter from end 14a-1 to end 14a-2 until it joins with truss 12b of unit cell set 10b. End 14a-2 has the same diameter as end 14b-1 of truss 12b. Truss 12b (also a horizontal truss) further increases in diameter from end 14b-1 to end 14b-2. The Y and Z trusses joined at end 14a-1 have the same diameter as end 14a-1. The Y and Z trusses common to sets 10a and 10b have the same diameter as end 14a-2 / 14b-1. The Y and Z trusses joined at end 14b-2 have the same diameter as end 14b-2. This configuration provides a continuous dielectric gradient that increases along the X and Y axes of the polymer structure 20. The dielectric gradient along the Z axis is constant.

[0029] The direction of the dielectric gradient can therefore be varied in a polymer structure by varying the diameter of the trusses in the unit cells accordingly, as shown in Figures 10A-10F. For example, the dielectric constant can be varied in three dimensions from a common point, as shown in Figure 10A, where the arrows indicate a continuous uniform decrease in dielectric constant in three dimensions from the center point 30 of the hemisphere to the edge of the hemisphere.

[0030] FIG. 10B shows a cross-sectional view of a cylinder divided longitudinally into three sections, an inner section, a middle section, and an outer section. The inner section has a first dielectric constant, the middle section has a second dielectric constant, and the outer section has a third dielectric constant, providing a radial step gradient dielectric constant. In one embodiment, the first dielectric constant can be lower than the second dielectric constant, which can be lower than the third dielectric constant. Alternatively, in another embodiment, the first dielectric constant can be higher than the second dielectric constant, which can be higher than the third dielectric constant. In yet another embodiment, the first dielectric constant can be higher than the second dielectric constant, and the third dielectric constant can be higher than the first and second dielectric constants.

[0031] Figure 10C shows a frusto-conical shape divided horizontally into sections 32, 34, and 36, with arrows indicating the decrease in dielectric constant from sections 32 to 34, 36. As shown in another embodiment in Figure 10D, sections 42 and 46 can have the same first dielectric constant and sections 44 and 48 can have the same second dielectric constant, with either the first or second dielectric constant being higher or lower than the other, providing a periodic step gradient.

[0032] FIG. 10D shows a cubic polymeric structural shape divided into sections 42, 44, 46, and 48. Sections 42, 46 can have the same first dielectric constant, and sections 44, 48 can have the same second dielectric constant. The first dielectric constant can be greater than or less than the second dielectric constant, thereby establishing a periodic dielectric constant gradient. Other variations in the gradient are also possible. For example, the gradient can vary randomly or pseudo-randomly from one point of the structure to another.

[0033] In another embodiment, FIG. 10E shows a cubic polymeric structure shape having a first vertex 52a and a second vertex 52b. The dielectric constant can vary continuously throughout the shape from the first vertex 52a to the second vertex 52b. In yet another embodiment, FIG. 10F shows a cubic polymeric structure shape having a first vertex 52a and a second vertex 52b. A first section 53 shown in the shape of a cylinder is disposed between the first vertex 52a and the second vertex 52b. A second section 54 surrounds the first section 53. The first section 53 can have a first dielectric constant and the second section 54 can have a second dielectric constant, the first and second dielectric constants being different. It is also possible to vary the dielectric constant of each section independently. For example, the first section 53 can have a dielectric constant that increases in a step gradient from the vertex 52a to the vertex 52b, while the section 54 can have a single dielectric constant.

[0034] In some embodiments, the interstitial spaces of each unit cell (e.g., 13c in FIG. 8 and 13b in FIG. 9) are filled with air. In other embodiments, the interstitial spaces can be filled with a dielectric material. Such filling can be done by impregnating the polymer structure after fabrication. The dielectric material filler can have a lower dielectric constant than the material used to form at least some of the trusses. For example, in some embodiments, the dielectric filler has a very low dielectric constant (e.g., polytetrafluoroethylene (PTFE)) and can be present to provide additional support to the trusses of the polymer structure. This can allow for the fabrication of very thin trusses or provide stiffness to more flexible trusses. In other embodiments, the polymer structure can be formed using a low dielectric constant material and then filled with a higher dielectric constant material. This technique can be useful to provide polymer structures with an overall higher dielectric constant gradient.

[0035] As will be apparent to one of skill in the art from the above discussion, the direction of the dielectric gradient can be changed in any direction by changing the diameter of the set of trusses in the desired direction. Different shaped gradients can also be fabricated, and even different shaped gradients within a single polymer structure. There can be a combination of step gradients and continuous gradients, for example a first section having a step gradient adjacent to a second section having a continuous gradient. The particular gradient or combination of gradients used can be selected based on the end purpose of the polymer structure.

[0036] These complex features can be easily obtained by using SLA techniques, which allows for the easy fabrication of desired gradients in any direction and in any shape within a polymer structure. The magnitude, i.e., range, of the gradient can vary widely depending on the type of unit cell, the diameter of the truss, and the materials used. For example, the dielectric constant can range from greater than 1 (i.e., greater than the dielectric constant of air) to 20, measured at 10 GHz, 50% relative humidity, and 23° C., respectively. Any gradient of dielectric constant within this range can be obtained, e.g., 1.1 to 10, 1.1 to 5, or 1.1 to 3 across the polymer structure, measured at 10 GHz, 50% relative humidity, and 23° C., respectively. Alternatively, the dielectric constant gradient can be 5 to 20, or 5.1 to 18, or 5.1 to 15, or 5.5 to 11, or 6 to 10 across the polymer structure, measured at 10 GHz, 50% relative humidity, and 23° C., respectively.

[0037] For example, WO2014 / 126837 describes a specific SLA method. The SLA method further allows for the use of various radiation-curable resins to form the polymer structure. A particular radiation-curable resin composition is selected based on its suitability for use in the SLA method (i.e., it can be provided in liquid form) and to provide the desired mechanical and electrical properties to the polymer structure. The liquid resin composition for forming the polymer structure can include radiation-curable, i.e., photocurable and / or free-radical curable monomer components and photoinitiator components. "Monomer" as used herein includes photocurable compounds, oligomers, prepolymers, and polymers. "Curable" and "curable" include polymerizable and crosslinkable, and polymerizable and curable. Suitable monomers include radiation curable groups such as acrylic (CH2=CHCOO-), methacrylic (CH2=C(CH3)COO), acrylamide (CH2=CHCONH-, methacrylamide (CH2=C(CH3)CONH), vinyl (CH2=CH-), allyl (CH2=CH-CH2-), other alkenes such as unsaturated aromatics (e.g., styrenic), cyclic alkenes, alkynes, carbon monoxide, or combinations thereof. For convenience, "radiation curable group" includes groups that are curable in the presence of an initiator that can be photoactivated, such as a cationic photoinitiator. Such groups include epoxies, vinyl ethers, heterocyclic groups such as lactones, lactams, and the like. The monomers may be linear, branched, cyclic, or crosslinked, and may have one or more functional groups, such as one or more acrylic groups (e.g., trifunctional acrylate monomers) or one or more vinyl groups (e.g., divinyl ether). Examples of liquid monomers and initiators include, but are not limited to, those described in WO2016 / 153711, US8232043, US8119214, US7935476, US7767728, US7649029, WO2012 / 129968, CN102715751, and JP2012-210408.

[0038] Exemplary monomers and multifunctional monomers include radiation curable silicones, urethane acrylates, urethane methacrylates, (C 1-6 alkyl) acrylate, (C 1-6 alkyl) methacrylates, such as methyl methacrylate, urethane dimethacrylate, 1,3-glycerol dimethacrylate, 1,6-hexanediol diacrylate, 1,6-hexanediol dimethacrylate, 1,4-butanediol diacrylate, 1,4-butanediol dimethacrylate, methylene glycol dimethacrylate, diethylene glycol divinyl ether, methylene glycol divinyl ether, 1,4-cyclohexanedimethylol divinyl ether, dipropylene glycol divinyl ether, tripropylene glycol divinyl ether, 1,6-hexanediol divinyl ether, and 1,4-butanediol divinyl ether, methoxyethene, 4-methoxystyrene, styrene, 2-methylprop-1-ene, 1,3-butadiene, oxirane, thietane, tetrahydrofuran, oxazoline, 1,3,-dioxepane, and oxetan-2-one.

[0039] The photoinitiator component includes one or more photoinitiators. For example, the photoinitiator component can include one or more free radical photoinitiators or one or more cationic photoinitiators. Photoinitiators known in the art for use in compositions for SLA processes can be used. Exemplary free radical photoinitiators include compounds that generate free radicals upon exposure to radiation, such as ultraviolet and / or visible light, in an amount sufficient to initiate a polymerization reaction. The free radical photoinitiator can be a single compound, a mixture of two or more active compounds, or a combination of two or more different compounds (such as co-initiators).

[0040] Exemplary cationic photoinitiators include compounds that form aprotic or Bronsted acids upon exposure to radiation, such as ultraviolet and / or visible light, in an amount sufficient to initiate polymerization. The cationic photoinitiator used can be a single compound, a mixture of two or more active compounds, or a combination of two or more different compounds (such as coinitiators). Examples of cationic photoinitiators include onium salts, sulfonium salts, and iodonium salts, such as diphenyl iodide hexafluorophosphate, diphenyl iodide hexafluoroarsenate, diphenyl iodide hexafluoroantimonate, diphenyl p-methoxyphenyl triflate, diphenyl p-toluenyl triflate, diphenyl p-isobutylphenyl triflate, diphenyl p-tert-butylphenyl triflate, triphenylsulfonium hexafluorophosphate, triphenylsulfonium hexafluoroarsenate, triphenylsulfonium hexafluoroantimonate, and triphenylsulfonium triflate, dibutylnaphthylsulfonium triflate, as described in U.S. Pat. No. 7,824,839, U.S. Pat. No. 7,550,246, U.S. Pat. No. 7,534,844, and the "Photoacid Generator Selection Guide for the electronics industry and energy curable coatings" (BASF 2010). Cationic photoinitiators can be used in conjunction with photosensitizers, such as 9,10-diethoxyanthracene, to enable the cationic photoinitiator to be activated over a broader range of wavelengths.

[0041] The radiation curable resin composition can have additional components solubilized therein, including thermosetting resin components, thermoset initiators, pigments, dyes, flame retardants, antioxidants, plasticizers, polymerization inhibitors, and the like, depending on the purpose of the polymer structure being produced.

[0042] In some embodiments, the radiation curable resin composition further comprises a thermosetting resin component and a thermosetting initiator component to initiate thermal curing. The inclusion of the thermosetting resin component allows for multi-stage curing of the polymer structure. A radiation curable composition comprising a thermosetting resin component and a thermosetting initiator component is described, for example, in WO2017 / 040883. Examples of monomers that can be used as the thermosetting resin component include 1,3-dicyanatobenzene, 1,4-dicyanatobenzene, 1,3,5-tricyanatobenzene, 1,3-dicyanatonaphthalene, 1,3,6-tricyanatonaphthalene, 2,2'-dicyanatobiphenyl, bis(4-cyanatophenyl)methane, 4-chloro-1,3-dicyanatobenzene, cyanated novolacs produced by reacting novolacs with cyanogen halides, and cyanated bisphenol polycarbonate oligomers produced by reacting bisphenol polycarbonate oligomers with cyanogen halides. Examples of thermal cure initiators include peroxides, some nucleophilic catalysts, or some metal catalysts, as are known in the art.

[0043] The relative amounts of each component of the radiation curable resin composition can be, for example, 10 to 95 weight percent (wt %) of the radiation curable monomer component, 0.11 to 15 wt % of the photoinitiator component, 0 to 90 wt % of the thermosetting resin component, and 0 to 10 wt % of the thermoset initiator component, each based on the total weight of the composition.

[0044] A typical method for SLA fabrication of polymer structures with spatially graded dielectric constant generally includes the steps of providing a quantity of the liquid radiation curable composition described above, irradiating a portion of the liquid radiation curable composition with activating radiation in a pattern to form a layer of the polymer structure on a substrate, contacting the formed layer with the liquid radiation curable composition, irradiating a portion of the liquid radiation curable composition with activating radiation in a pattern to form a next layer of the polymer structure, and repeating the contacting and irradiating to form a polymer structure, the polymer structure comprising a plurality of unit cells, each unit cell being defined by a plurality of trusses formed by the irradiation, the trusses of each unit cell being dimensioned to provide a spatially graded dielectric constant. In a preferred embodiment, the method is a stereolithography method, for example as described in US Pat. No. 9,205,601.

[0045] After the polymeric material is produced, the 3D printed polymeric material can be optionally post-cured, for example, to further photopolymerize. If a thermosetting resin composition is included in the radiation curable composition, the post-curing can be thermal, for example by exposure to heat in an oven. Such dual radiation curing and thermal curing is described, for example, in WO2017 / 040. Both radiation and thermal post-curing can be used.

[0046] In one embodiment, the polymeric material is in contact with the conductive layer. In some embodiments, at least two alternating polymeric structures or at least two alternating layers of conductive layer are present to form a laminate. Conductive materials useful for the conductive layer include, for example, stainless steel, copper, gold, silver, aluminum, zinc, tin, lead, transition metals, or combinations thereof. There is no particular limitation on the thickness of the conductive layer, nor any limitation on the shape, size, or texture of the surface of the conductive layer. The conductive layer can have a thickness of 1 to 2000 micrometers, or 10 to 1000 micrometers. When there are two or more conductive layers, the thickness of each layer can be the same or different. The conductive layer can include a copper layer. Suitable conductive layers include thin layers of conductive metals, such as copper foil, e.g., electrodeposited copper foil, currently used to form circuits.

[0047] The conductive layer can be contacted with the polymer structure by placing the conductive layer on a platform used in the additive manufacturing process and printing onto the conductive layer. Alternatively, the polymer material can be contacted with the conductive layer by direct laser structuring or by adhesion. If permitted by the particular material and morphology of the polymer material, the conductive layer can be applied using other methods known in the art, such as electrodeposition, chemical vapor deposition, etc.

[0048] For example, the conductive layer can be applied by laser direct structuring. Here, the 3D printed polymer material can include a laser direct structuring additive, and the laser direct structuring can include irradiating the surface of the substrate with a laser, forming a track of the laser direct structuring additive, and applying a conductive metal to the track. The laser direct structuring additive can include metal oxide particles (such as titanium oxide and copper chromium oxide). The laser direct structuring additive can include spinel-based inorganic metal oxide particles, such as spinel copper. The metal oxide particles can be coated with a composition including, for example, tin and antimony (e.g., 50 to 99 wt% tin and 1 to 50 wt% antimony, based on the total weight of the coating). The laser direct structuring additive can include 2 to 20 parts of additive, based on 100 parts of the respective composition. The irradiation can be performed with a YAG laser having a wavelength of 1,064 nanometers, under a power of 10 watts, a frequency of 80 kilohertz (kHz), and a speed of 3 meters per second. The conductive metal may be applied using a plating process, for example in an electroless plating bath containing copper.

[0049] The conductive layer can be brought into contact by adhesion. In one embodiment, the polymer structure can be first formed by photopolymerization. When a thermal curing agent is present in the polymeric material composition, the polymer structure and the conductive layer can be brought into contact and adhered by thermal curing of the polymeric material in the polymer structure. This technique allows for "B-staging" of the polymer structure. This is particularly useful when a multi-layer structure is desired. For example, multiple layers of the polymer structure can be manufactured (B-stage), a stack of alternating polymeric and conductive layers can be made, and the stack can then be heat-cured to adhere the layers. In another embodiment, the polymer structure can be manufactured in the form of a flat sheet (B-stage), the conductive layer can be brought into contact with the flat sheet, the layers can be rolled to provide a cylinder of alternating polymeric and conductive layers, and the roll can be heat-cured to adhere the layers.

[0050] Alternatively, or in addition, an adhesive layer can be disposed between the conductive layer or layers and the polymeric material.

[0051] Polymer structures can be used as or in electronic devices, for example, as impedance matching layers, dielectric waveguides, lenses, reflector arrays, antenna matching structures, superstrates, couplers, frequency dividers, and dielectric antennas (including dielectric resonator antennas and dielectric rod antennas).

[0052] As disclosed herein, and with reference to all of the foregoing, and with particular reference to FIG. 11 , an electronic structure or device 100, in particular an electromagnetic (EM) structure or device, may include a first dielectric portion (1DP) 20.1 of any dielectric structure 20 disclosed herein, for example in the form of a dielectric resonator antenna (DRA), and a second dielectric portion (2DP) 20.2 of any dielectric structure 20 disclosed herein, for example in the form of a dielectric lens, such as a Luneburg lens, or any other dielectric element forming, for example, an electromagnetic (EM) far-field beam shaper, or any other dielectric element forming, for example, a dielectric waveguide or an EM near-field radiation conduit. As disclosed herein and as will be understood by those skilled in the art, the 1DP and 2DP are distinguishable from one another in that the 1DP is structurally configured and adapted to have an EM resonant mode that matches the EM frequency of an electrical signal source electromagnetically coupled to the 1DP, and the 2DP is structurally configured and adapted to serve to influence the EM far-field radiation pattern that emerges from the 1DP when excited without itself having a resonant mode that matches the EM frequency of the electrical signal source, in the case of a dielectric EM far-field beam shaper, or to propagate the EM near-field radiation that emerges from the 1DP when excited with little or no EM signal loss along the length of the 2DP, in the case of a dielectric EM near-field radiating conduit. As disclosed herein, the phrase electromagnetic coupling is a term of art that refers to the intentional transfer of EM energy from one location to another without necessarily physical contact between the two locations, and more specifically with respect to one embodiment disclosed herein, refers to the interaction between electrical signal sources having EM frequencies that match the EM resonant modes of the 1DP associated with the 1DP and / or the 1DP combined with the 2DP. In one embodiment, the electromagnetic coupling configuration is selected such that for a selected operating free-space wavelength associated with the EM device, greater than 50% of the resonant mode EM energy in the near field is within 1DP.In some embodiments, the height H2 of the 2DP is greater than the height H1 of the 1DP (e.g., the height of the 2DP is greater than 1.5 times the height of the 1DP, or the height of the 2DP is greater than twice the height of the 1DP, or the height of the 2DP is greater than three times the height of the 1DP). In some embodiments, the average dielectric constant of the 2DP is less than the average dielectric constant of the 1DP (e.g., the average dielectric constant of the 2DP is less than 0.5 of the average dielectric constant of the 1DP, or the average dielectric constant of the 2DP is less than 0.4 of the average dielectric constant of the 1DP, or the average dielectric constant of the 2DP is less than 0.3 of the average dielectric constant of the 1DP). In some embodiments, the 2DP has axial symmetry about a specified axis (e.g., the z-axis shown in FIG. 11). In some embodiments, the 2DP has axial symmetry about an axis perpendicular to the electrical ground plane 102 on which the 1DP is disposed.

[0053] As mentioned above, the method described herein allows for the rapid and efficient production of materials with preselected dielectric constant gradients in a variety of compositions, in a variety of configurations and in a variety of shapes. This method has many other advantages, including dramatically reducing the time from design to prototyping to commercialization. Design changes can be made quickly since no tooling is required. Minimal energy is used compared to injection molding or other molding processes. The use of additive manufacturing can also reduce the amount of waste and raw materials. This method can further be used to facilitate the production of geometrically complex parts. This method can further reduce part inventory for a business since parts can be rapidly made on demand and on-site.

[0054] Set forth below are various non-limiting aspects of the present disclosure.

[0055] Aspect 1: A stereolithography method of fabricating a polymer structure having a spatially gradient dielectric constant, the method comprising the steps of: providing a quantity of a liquid radiation curable composition; irradiating a portion of the liquid radiation curable composition with activating radiation in a pattern to form a layer of the polymer structure; contacting the layer with the liquid radiation curable composition; irradiating the liquid radiation curable composition with activating radiation in a pattern to form a second layer on the first layer; and repeating the contacting and irradiating steps to form the polymer structure, the polymer structure comprising a plurality of unit cells, each unit cell integrally connected to adjacent unit cells, each unit cell defined by a plurality of trusses formed by the irradiating step, the trusses being integrally connected to one another at their respective ends, the trusses of each unit cell being dimensioned to provide the spatially gradient dielectric constant.

[0056] Aspect 2: The method of aspect 1, wherein the unit cell structure is an octet structure.

[0057] Embodiment 3a: The method of any one or more of the preceding embodiments, wherein each of the unit cells can have a size that is less than 30%, or less than 20%, or less than 10% of the wavelength of electromagnetic radiation at which the polymer structure is operable.

[0058]

[0033] Embodiment 3b: The method of any one or more of the preceding embodiments, wherein the polymer structure is operable within a wavelength of electromagnetic radiation ranging from 3 to 300 millimeters.

[0059] Aspect 4: The method of any one or more of the preceding aspects, wherein each truss has an average diameter in the range of 0.03 to 5.0 millimeters, preferably 0.05 to 4.0 millimeters.

[0060] Aspect 5: The method of any one or more of the preceding aspects, wherein the dielectric constant gradient is a step gradient.

[0061] Embodiment 6: The method of any one or more of the preceding embodiments, wherein the dielectric gradient is a continuous gradient.

[0062] Embodiment 7: The method of any one or more of the preceding embodiments, wherein the dielectric gradient has endpoints in the range of 20 to greater than 1, measured at 10 GHz, 23° C., and 50% relative humidity.

[0063]

[0036] Aspect 8: The method of any one or more of the preceding aspects, further comprising the step of impregnating the polymer structure with a dielectric material.

[0064] Aspect 9: The method of any one or more of the previous aspects, wherein the liquid radiation curable composition comprises a thermally curable component, and the method further comprises the step of thermally curing the polymer structure.

[0065] Example 10: The method of example 9, comprising contacting the polymer structure with a conductive substrate and thermally curing the polymer structure.

[0066] Example 11: The method of example 9, further comprising contacting at least two alternating layers of the polymer structure or at least two layers of the conductive substrate to form a laminate, and thermally curing the polymer structure in the laminate.

[0067] Embodiment 12: A polymer structure having a spatially gradient dielectric constant formed by any of the previous embodiments.

[0068] Example 13: An electronic device comprising the polymer structure of Example 12, the device being an impedance matching layer, a dielectric waveguide, a lens, a reflector array, an antenna matching structure, a superstrate, a coupler, a frequency divider, or a dielectric antenna.

[0069] Aspect 14: An electronic device comprising a polymer structure, the polymer structure comprising a body of dielectric material comprising a plurality of unit cells, each unit cell comprising a plurality of trusses integrally connected to one another at their respective ends, each unit cell being integrally connected to an adjacent one of the unit cells, and an average dielectric constant of the body of dielectric material varies from one portion of the body to another portion of the body.

[0070] Example 15: The electronic device of Example 13, wherein the plurality of trusses are integrally connected to one another only at their respective ends.

[0071] Example 16: The electronic device of any one or more of Examples 14 to 15, wherein each unit cell of the plurality of unit cells has an octet lattice structure.

[0072] Example 17: The electronic device of any one or more of Examples 14 to 16, wherein each unit cell of the plurality of unit cells includes an interstitial space between the plurality of trusses.

[0073] Example 18: The electronic device of Example 17, wherein the interstitial space comprises air.

[0074] Example 19: The electronic device of example 18, wherein the interstitial space comprises a dielectric material other than air.

[0075]

[0041] Embodiment 20: The electronic device of any one or more of embodiments 14 to 19, wherein an average dielectric constant of a body of dielectric material decreases in a direction from an inner portion of the body to an outer portion of the body.

[0076]

[0041] Example 21: The electronic device of any one or more of Examples 14 to 19, wherein the average dielectric constant of a body of dielectric material varies periodically from a first portion of the body to a second portion of the body.

[0077] Example 22: Any one or more of the electronic devices of Examples 14 to 21, wherein the multiple trusses of a given unit cell have constant cross-sectional dimensions.

[0078] Example 23: Any one or more of the electronic devices of Examples 14 to 21, wherein the multiple trusses of a given unit cell have non-constant cross-sectional dimensions.

[0079] Embodiment 24: Any one or more of the electronic devices of embodiments 14 to 22, wherein the cross-sectional dimension is a circular cross-sectional dimension.

[0080] Embodiment 25: The electronic device of embodiments 22 to 24, wherein the non-constant cross-sectional dimension decreases in a direction from the inner portion of the unitary body to the outer portion of the unitary body.

[0081]

[0041] Aspect 26: Any one or more of the electronic devices of aspects 14 to 25, wherein each truss of the plurality of trusses has an overall maximum cross-sectional dimension in the range of 0.03 to 5.0 millimeters.

[0082]

[0041] Aspect 27: The electronic device of any one or more of aspects 14 to 26, wherein the spatially graded dielectric constant of the unitary body of dielectric material is greater than 20 to 1, measured at 10 GHz, 23°C, and 50% relative humidity.

[0083]

[0041] Embodiment 28: The electronic device of any one or more of embodiments 14 to 27, further comprising at least one electrical conductor disposed in contact with the unitary body of dielectric material.

[0084] Example 29: The electronic device of Example 28, wherein at least one electrical conductor is adhered to the body of dielectric material via an adhesive material.

[0085] Aspect 30: The electronic device of any one or more of aspects 14 to 29, wherein the unity of dielectric material forms at least a portion of an impedance matching layer, a dielectric waveguide, a lens, a reflector array, an antenna matching structure, a superstrate, a coupler, a divider, or a dielectric antenna.

[0086] Example 31: The electronic device of example 30, wherein the unity of dielectric material is a first dielectric portion 1DP of the electronic device and further includes a second dielectric portion 2DP, 1DP having a proximal end and a distal end, 2DP having a proximal end and a distal end, and the proximal end of the 2DP is positioned near the distal end of the 1DP.

[0087] Embodiment 32: The electronic device of embodiment 31, further comprising an electrical ground plane on which the 1DP is disposed.

[0088] Embodiment 33: Any one or more electronic devices of embodiments 31 to 33, wherein the height H2 of 2DP is greater than the height H1 of 1DP.

[0089] These compositions, methods, and articles can alternatively comprise, consist, or consist essentially of any suitable materials, steps, or components disclosed herein. These compositions, methods, and articles can additionally, or alternatively, be formulated to be devoid of, or substantially free of, any materials (or species), steps, or components that are not otherwise necessary to the function or accomplishment of the purpose of these compositions, methods, and articles.

[0090] The terms "a" and "an" denote the presence of at least one of the referenced items, rather than a limitation of quantity. The term "or" means "and / or" unless the context clearly indicates otherwise. References throughout the specification to "one embodiment," "another embodiment," and "several embodiments" mean that the particular element (e.g., feature, structure, step, or characteristic) described in connection with that embodiment is included in at least one embodiment described herein and may or may not be present in other embodiments. In addition, it should be understood that the described elements can be combined in any suitable manner in the various embodiments. The term "combination" includes blends, mixtures, alloys, reaction products, and the like. Also, "at least one of" means that the list includes each element individually, as well as combinations of two or more elements of the list, and combinations of at least one element of the list with similar elements not listed. Similarly, "combinations of these" are open and can include at least one of the listed elements, optionally with similar or equivalent elements not listed.

[0091] The endpoints of all ranges directed to the same component or property are inclusive, independently combinable, and include all intermediate points and ranges, e.g., a range of "up to 25 wt%, or from 5 to 20 wt%" includes the endpoints and all intermediate values ​​of the range "from 5 to 25 wt%, such as 10 to 23 wt%.

[0092] When an element such as a layer, film, region, or substrate is referred to as being "in contact with" or "in contact with" another element, it may be in direct contact with or in direct contact with the other element, or there may be intervening elements present. In contrast, when an element is referred to as being "in direct contact with" or in direct contact with another element, there are no intervening elements present. Terms such as first, second, third, etc. may be used herein to describe various elements, components, regions, layers, or sections, but these elements, components, regions, layers, or sections should not be limited by these terms. These terms are used only to distinguish one element, component, aspect, region, layer, or section from another element, component, region, layer, or section. Thus, a first element, component, region, layer, or section discussed below may also be referred to as a second element, component, region, layer, or section without departing from the teachings of the present embodiment.

[0093] Exemplary embodiments are described herein with reference to cross-sectional views, which are schematic illustrations. Thus, variations from the shapes of the illustrations are to be expected as a result, for example, of manufacturing techniques and / or tolerances. Thus, the embodiments described herein should not be construed as limited to the specific shapes or relative sizes of regions as shown herein, but are intended to include deviations in shapes that result, for example, from manufacturing or design. For example, regions illustrated or described as flat may typically have rough and / or non-linear features. Also, sharp angles that are illustrated may be rounded. Thus, the regions illustrated in the figures are schematic in nature, and the shapes are not intended to illustrate the exact shapes or relative sizes of the regions, and are not intended to limit the scope of the claims.

[0094] Unless specified to the contrary herein, all test standards are the latest standards in effect as of the filing date of this application or, if priority is claimed, the filing date of the earliest application in which the test standards are listed.

[0095] Unless otherwise specified, technical and scientific terms used herein have the same meaning as commonly understood by those skilled in the art to which this invention belongs.All cited patents, patent applications, and other references are incorporated herein by reference in their entirety.However, if a term in this application contradicts or conflicts with a term in an incorporated reference, the term from this application shall take precedence over the conflicting term from the incorporated reference.

[0096] While particular embodiments have been described, alternatives, modifications, variations, improvements, and substantial equivalents that are not presently foreseen or possible may occur to applicant or others skilled in the art, and accordingly, the appended claims as submitted and as they may be amended are intended to cover all such alternatives, modifications, variations, improvements, and substantial equivalents. [Explanation of symbols]

[0097] 10 unit cells 10a Unit cell 10b Unit cell 10c Unit cell 12 Truss 12a Truss 12b Truss 13 Interstitial space Gap 13a Gap 13b Gap 13c 14 End 14b-1 End 14b-2 End 20 octet unit cell, polymer structure 30 center point 32 Section 34 Section 36 Section 42 Section 44 Section 46 Section 48 Section 52a First Peak 52b The second peak 53 First Section 54 Second Section 100 Electronic Structures or Devices 102 Electrical Ground Plane

Claims

1. 1. A polymer structure having a spatially gradient dielectric constant, said polymer structure comprising: a body of dielectric material including an open lattice cell structure including a plurality of unit cells, each unit cell being integrally connected to an adjacent unit cell; the average dielectric constant of said body of said dielectric material varies from one portion of the body to another portion of the body; A polymer structure, wherein the spatially graded dielectric constant of the polymer structure has endpoints ranging from 20 to greater than 1, measured at 10 GHz, 23° C., and 50% relative humidity.

2. 10. The polymer structure of claim 1, wherein the average dielectric constant of the body of dielectric material decreases in a direction from the interior of the body to the exterior of the body.

3. 10. The polymer structure of claim 1, wherein an average dielectric constant of said body of dielectric material varies periodically from a first portion of said body to a second portion of said body.

4. 2. The polymer structure of claim 1, wherein the spatially graded dielectric constant of the body of dielectric material is greater than 10 to 1, measured at 10 GHz, 23° C., and 50% relative humidity.

5. 10. The polymer structure of claim 1, wherein the spatially graded dielectric constant of the body of dielectric material is greater than 5 to 1, measured at 10 GHz, 23°C, and 50% relative humidity.

6. 10. The polymer structure of claim 1, further comprising at least one electrical conductor disposed in contact with said body of dielectric material.

7. 10. The polymer structure of claim 1, wherein each of said unit cells has a size that is less than 30% of a wavelength of electromagnetic radiation in which said polymer structure is operable.

8. The polymer structure of claim 1 , wherein the spatially graded dielectric constant comprises a step gradient.

9. The polymer structure of claim 1 , wherein the spatially graded dielectric constant comprises a continuous gradient.

10. 10. The polymer structure of claim 1, wherein the density of the polymer structure is varied to provide a spatially graded dielectric constant having endpoints in the range from 20 to greater than 1, measured at 10 GHz, 23° C., and 50% relative humidity.

11. 10. An electronic device comprising the polymer structure of claim 1, wherein the unity of dielectric material forms at least a portion of an impedance matching layer, a dielectric waveguide, a lens, a reflector array, an antenna matching structure, a superstrate, a coupler, a frequency divider, or a dielectric antenna.

12. said unity of dielectric material being a first dielectric portion 1DP of said electronic device and further comprising a second dielectric portion 2DP; the 1DP having a proximal end and a distal end; the 2DP having a proximal end and a distal end; The proximal end of the 2DP is disposed near the distal end of the 1DP.

12. The electronic device of claim 11.

13. The electronic device of claim 12 further comprising an electrical ground plane on which the 1DP is disposed.

14. The electronic device of claim 12 , wherein the 2DP height H2 is greater than the 1DP height H1.

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