Low dielectric constant radio frequency substrate, its assembly, and method for manufacturing the same

Abstract

The substrate includes a monolithic structure formed from a dielectric material having a first side, a second side, and an intermediate region between the first and second sides, the intermediate region having a lattice structure of the dielectric material, the lattice structure having a plurality of interstitial spaces between the dielectric materials of the lattice structure. The lattice structure extends between and is monolithically connected to the first and second sides, and at least one of the first and second sides has a substantially solid surface suitably configured to support one or more of electronic circuit imaging, electroplating, metal deposition, or vias between the first and second sides.

Description

Technical Field

[0001] Cross - reference to Related Applications This application claims the benefit of U.S. Provisional Application No. 63 / 357,386, filed Jun. 30, 2022, and U.S. Application No. 18 / 215,570, filed Jun. 28, 2023, the entire contents of which are incorporated herein by reference.

[0002] The present disclosure generally relates to low - dielectric - constant radio - frequency substrates, assemblies thereof, and methods of fabricating the same.

Background Art

[0003] Substrates having a low dielectric constant or low Dk (dielectric constant) are often preferably used for certain RF (radio - frequency) radiating elements such as patch antennas. In these antenna structures, as the Dk of the substrate decreases, the portion of the electric field that is confined becomes smaller, the energy stored in the substrate decreases, enabling higher radiation efficiency, wider bandwidth, and increased - gain antennas. While mimicking air with Dk = 1, the materials currently used to provide rigidity and support for printed antennas are typically formed from foamed polymer materials. However, foamed materials prohibit common manufacturing techniques such as plated vias for stacked - patch designs and other multilayer circuit designs. Additionally, because foamed materials are porous and cannot be directly metallized and / or imaged on the surface, other circuit materials must be laminated on the foamed surface, resulting in additional processing complexity. Therefore, end - users must either overcome the challenges of constructing a low - Dk substrate system or use high - Dk laminates.

[0004] Conventional solutions have required laminating circuit materials onto foamed spacers (typically pre - imaged to avoid the penetration of process chemistry into the foam) and passing z - axis wires through to connect the circuit planes above and below the low - Dk space (foam) since vias cannot be drilled and plated.

[0005] While existing foamed polymer substrates useful for RF applications may be suitable for their intended purposes, the technology for low dielectric constant RF substrates will advance with substrates that overcome one or more of the above-described limitations. SUMMARY OF THE INVENTION MEANS FOR SOLVING THE PROBLEM

[0006] One embodiment includes a substrate, an assembly, and a method as defined by the appended independent claims. Further advantageous variations of the substrate, assembly, and method are defined by the appended dependent claims.

[0007] One embodiment includes a substrate having a monolithic structure formed from a dielectric material having a first side, a second side, and an intermediate region between the first side and the second side, the intermediate region having a lattice structure of the dielectric material having a plurality of interstitial spaces between the lattice-structured dielectric materials, the lattice structure extending between and being monolithically connected to the first side and the second side, and at least one of the first side and the second side having a substantially solid surface suitably configured to support one or more of electronic circuit imaging, electroplating, metal deposition, or vias between the first side and the second side.

[0008] One embodiment includes a multilayer assembly having two or more of the above-described substrates, each of the substrates being mechanically attached, adhered, or fused to one of the adjacent substrates.

[0009] One embodiment includes a method of fabricating the above-described substrate having the above-described monolithic structure, the method including, in a continuous process, forming a first side of the substrate, and, via the continuous process, forming monolithically therewith on the first side an intermediate region of the substrate, the intermediate region having a lattice structure of the dielectric material having a plurality of interstitial spaces between the lattice-structured dielectric materials, and, via the continuous process, forming monolithically therewith on the intermediate region a second side of the substrate.

[0010] The above features and advantages of the present invention, as well as other features and advantages, will be apparent immediately from the following detailed description of the present invention in connection with the accompanying drawings.

[0011] Reference is made to the exemplary and non-limiting drawings, in which like elements are numbered alike in the accompanying figures.

Brief Description of the Drawings

[0012]

Figure 1A

Figure 1B

Figure 2A

Figure 2B

Figure 3A

Figure 3B

Figure 4A

Figure 4B

Figure 4C

Figure 4D

Modes for Carrying Out the Invention

[0013] Those skilled in the art will understand that the drawings further described hereinbelow are for illustrative purposes only. For the sake of brevity and clarity of illustration, it will be appreciated that the elements shown in the figures are not necessarily drawn to scale. For example, the dimensions or scale of some of the elements may be exaggerated relative to other elements for clarity. Further, where appropriate, reference numerals may be repeated in the figures to indicate corresponding or similar elements, or similar elements may not be repeated in all of the figures, and in the absence of such repetition, it will be recognized and understood that they are inherently disclosed.

[0014] As used herein, the phrase "embodiment" means "an embodiment disclosed and / or illustrated herein", and does not necessarily include a specific embodiment of the invention that complies with the appended claims, but is provided herein as being useful for a complete understanding of the invention that complies with the appended claims.

[0015] The following detailed description includes many details for illustrative purposes, but those skilled in the art will recognize that many variations and modifications of the following details are within the scope of the appended claims. For example, where the features described are not mutually exclusive with respect to other described features, such non-mutually exclusive combinations of features are considered to be inherently disclosed herein. Additionally, common features may be commonly illustrated in various figures, but for the sake of brevity may not be specifically enumerated in all figures, and yet will be recognized by those skilled in the art as being features that are explicitly disclosed, even if they need not be enumerated in a particular figure. Accordingly, the following examples of embodiments are presented without any loss of generality to the claimed invention disclosed herein and without imposing any limitations thereon.

[0016] As illustrated and described by various figures and accompanying text, one embodiment uses a lattice structure to provide a low dielectric constant dielectric, while providing one or more substantially solid surfaces on one or both sides of a substrate for electrical circuit imaging and also being configured to include one or more vias in-situ, providing a 3D printable or other additive manufacturing process substrate. While one embodiment described and illustrated herein represents a gyroidal lattice structure as an example of a structure for the substrate disclosed herein, other lattice structures may also be applicable for the purposes disclosed herein as described herein, and it will be appreciated that the invention disclosed herein and in the appended claims is not so limited.

[0017] As used herein, the term monolithic means a single material composition and / or a structure integrally formed from a single process without material discontinuities from one region of the structure to another, such as a structure produced from, for example, a plastic molding process, a 3D printing process, a deposition process or a machining process.

[0018] As used herein, the term substantially is intended to account for manufacturing tolerances and / or minor deviations, such as in the case of vias, that do not impair the intended performance or scope of the invention disclosed herein in accordance with the appended claims.

[0019] As described and illustrated herein, one embodiment includes a 3D printable substrate that is designed to use a lattice structure to provide a low dielectric constant while having the ability to create solid surfaces for circuit imaging and vias in-situ.

[0020] In one embodiment, the substrate may comprise a 3D lattice of a dielectric material with a solid printed film on one or both sides. In one embodiment, vias can be printed directly into the substrate by creating solid cylindrical walls within the lattice that lead to both ends of the substrate. Printing solid films on both sides can be utilized when using a ground plane or capacitive coupling patch element within a single component, but single (or double-sided) components can be incorporated into other structures.

[0021] In one embodiment, the printed lattice can have features that are very small compared to a fraction of the operating wavelength, typically less than a few hundred microns, and thus can operate as a single dielectric medium.

[0022] In one embodiment, the lattice structure may be a gyroidal lattice with good mechanical stability and even density distribution within the cells.

[0023] Some of the advantages of the embodiments disclosed herein may include one or more of the following: a solid, non-porous surface, mechanically robust, low dielectric constant substrate; an integrally formed via structure that connects elements on either side of the substrate; a single monolithic structure with better alignment and lower Dk; no need for additional lamination processes; and a lower dielectric constant than other copper-clad laminates.

[0024] Reference is now made in combination to FIGS. 1A, 1B, 2A, 2B, 3A and 3B.

[0025] In one embodiment, the substrate 100 includes a monolithic structure 102 formed from a dielectric material having a first side 200, a second side 300, and an intermediate region 400 between the first side 200 and the second side 300. In one embodiment, the intermediate region 400 has a lattice structure 403 of the dielectric material, having a plurality of interstitial spaces 402 (most clearly seen with reference to FIG. 3A) between the dielectric materials of the lattice structure 403, the lattice structure 403 extending between and being monolithically connected to the first side 200 and the second side 300. At least one of the first side 200 and the second side 300 includes a substantially solid surface 202, 302 suitably configured to support one or more of electronic circuit imaging, electroplating, metal deposition (collectively referred to herein by reference numeral 250) or vias 104 between the first side 200 and the second side 300. In one embodiment, the interstitial spaces 402 are formed entirely or at least partially from air. In one embodiment, the monolithic structure 102 is not formed from a foam and / or is not a laminated structure. As used herein, the term laminated structure means a structure having separate and distinct layers that are fixed together to form a rigid, flat or flexible material. In one embodiment, the lattice structure 403 is a gyroidal lattice structure, but may be any other surface-based lattice structure as opposed to a strut-based lattice structure. In one embodiment, the lattice structure 403 of the intermediate region 400 has a uniform distribution of the dielectric material and the interstitial spaces 402.

[0026] In one embodiment, both the first side 200 and the second side 300 have substantially solid surfaces 202, 302 (best seen in FIG. 2A) that are suitably configured to support one or more of electronic circuit imaging, electroplating, metal deposition 250 (best seen in FIG. 1B), or vias 104 (best seen in FIG. 3A) between the first side 200 and the second side 300. In one embodiment, the monolithic structure 102 of the substrate 100 includes one or more vias 104 (best seen in FIG. 3) that extend between the first side 200 and the second side 300. In one embodiment, the one or more vias 104 have a conductive (inner) surface that extends between the first side 200 and the second side 300 and serves to provide at least one conductive path between the first side 200 and the second side 300. In one embodiment, the first side 200, the second side 300, or both the first side 200 and the second side 300 of the monolithic structure 102 have a metal-coated surface with which the conductive vias 104 are in electrical contact. In one embodiment, the conductive vias 104 and the metal-coated surfaces of the first and second sides 200, 300 are metal-coated together in the same metal-coating process, such as, for example, metal evaporation.

[0027] In one embodiment, the dielectric material of the monolithic structure 102 of the substrate 100 has a relative dielectric constant of 1.01 or more and 5 or less, or alternatively 1.1 or more and 4.5 or less.

[0028] In one embodiment, the monolithic structure 102 of the substrate 100 is formed with respect to an orthogonal x-y-z coordinate system in which the z-axis is perpendicular to both the first side 200 and the second side 300, and the dielectric material includes ceramic fibers 150 substantially aligned with the x-y plane of the x-y-z coordinate system, ceramic fibers 160 substantially aligned with the z-axis of the x-y-z coordinate system, or both ceramic fibers 150 substantially aligned with the x-y plane of the x-y-z coordinate system and ceramic fibers 160 substantially aligned with the z-axis of the x-y-z coordinate system (best seen with reference to FIG. 3B). Although FIG. 3B represents only a few examples of the arrangement of the ceramic fibers 150, 160 in terms of quantity, width, and length, it is recognized that these arrangements are for illustrative purposes only, and that the quantity, width, and length of such ceramic fibers 150, 160 can vary according to the desired performance characteristics and in accordance with the embodiments disclosed herein.

[0029] In one embodiment, the first side 200 of the substrate 100 is planar, the second side 300 of the substrate 100 is planar, and the second side 300 is parallel to the first side 200 (best seen with reference to FIGS. 1 and 2A). In another embodiment, the first side 200 of the substrate 100 is provided equidistantly at a distance "T" from the second side 300 of the substrate 100. In one embodiment, the first side 200 of the substrate 100 and the second side 300 of the substrate 100 are curved (best seen with reference to FIG. 2B).

[0030] In one embodiment, the monolithic structure 102 of the substrate 100 is formed with respect to an orthogonal x-y-z coordinate system in which the z-axis is perpendicular to both the first side 200 and the second side 300, the substrate 100 operates at a given center frequency f having an operating wavelength λ, and the total thickness of the substrate 100 in the z-direction is λ / 2 or less, or alternatively λ / 4 or less. In one example embodiment, the given center frequency is 4.9 GHz and the z-direction thickness of the substrate is 4.0 mm.

[0031] Now, with reference to FIGS. 1, 2A, 2B, 3A, and 3B, refer also to FIGS. 4A, 4B, 4C, and 4D.

[0032] In one embodiment, as shown in FIGS. 4A, 4B, 4C, and 4D, a multilayer assembly 500 includes two or more substrates 100 (individually referred to by reference numerals 100.1, 100.2, etc. in FIGS. 4A, 4B, 4C, and 4D) as described herein and illustrated in FIGS. 1, 2A, 2B, 3A, and 3B, and a plurality (i.e., two or more) of substrates 100 are indicated by ellipsis 502 in FIG. 4A.

[0033] Referring to FIG. 4B in one embodiment, one substrate 100.1 is mechanically attached to another adjacent substrate 100.2 via a mechanical attachment structure 504 such that elastic deformable protrusions 510 on each substrate 100.1, 100.2, e.g., on adjacent ones of each substrate 100.1, 100.2, engage corresponding elastic deformable recesses 515 in a one-to-one alignment. Alternatively stated, each substrate 100.1, 100.2 has one or more mechanical alignment features 510, 515 that mechanically attach and engage corresponding ones of the mechanical alignment features 515, 510 of adjacent ones of the substrates 100.1, 100.2. In one embodiment, one or more of the mechanical alignment features 510, 515 and corresponding ones of the mechanical alignment features 515, 510 have an elastic deformable interference fit therebetween. In one embodiment, the elastic deformable protrusions 510 are fully or at least partially insertable into corresponding ones of the elastic deformable recesses 515.

[0034] Referring to FIG. 4C in one embodiment, one substrate 100.1 is adhered to another adjacent substrate 100.2 via an adhesive 506.

[0035] Referring to FIG. 4D in one embodiment, one substrate 100.1 is fused to another adjacent substrate 100.2 via a fusion interface 508.

[0036] In one embodiment, the multilayer assembly 500 is configured such that each monolithic structure 102 is formed with respect to an orthogonal x-y-z coordinate system in which the z-axis is perpendicular to both the first side 200 and the second side 300. The multilayer assembly 500 operates at a given frequency f having an operating wavelength λ, and the total thickness of the multilayer assembly 500 in the z-direction is λ / 2 or less, or alternatively λ / 4 or less.

[0037] In addition to the disclosure herein of the configuration for the 3D printable substrate 100 that uses the lattice structure 403 to provide a low dielectric constant dielectric to the substrate 100, it will be appreciated that a method for fabricating it is also disclosed herein.

[0038] In one embodiment, a method of fabricating a substrate 100 having a monolithic structure 102 as disclosed and illustrated herein includes, in a continuous process, forming a first side 200 of the substrate 100 and, via the continuous process, monolithically forming an intermediate region 400 of the substrate 100 on the first side 200, the intermediate region 400 being a lattice structure 403 of a dielectric material and having a plurality of interstitial spaces 402 between the dielectric materials of the lattice structure 403, and, via the continuous process, monolithically forming a second side 300 of the substrate 100 on the intermediate region 400.

[0039] In one embodiment of the method, the continuous process further includes forming one or more vias 104 that extend from the first side 200, through the intermediate region 400, to the second side 300.

[0040] In one embodiment, the method further includes imaging or metallizing an electronic circuit network 250 on at least one of a first side 200 and a second side 300 to provide electronic circuit imaging. FIG. 1B depicts a portion of a general-purpose electronic circuit network 250 having a plurality of conductive trace lines 252 and a plurality of conductive vias 104 (the same reference numbers used for the vias 104 represented in FIG. 3A since they are electrically connected to each other).

[0041] In one embodiment, a method of fabricating a substrate 100 includes forming a monolithic structure 102 with respect to an orthogonal x-y-z coordinate system where the z-axis is perpendicular to both the first side 200 and the second side 300. Through a continuous process, the method further includes forming ceramic fibers 150 within a dielectric material that are substantially aligned with the x-y plane of the x-y-z coordinate system, substantially aligned with the z-axis of the x-y-z coordinate system, or substantially aligned with the x-y plane of the x-y-z coordinate system and substantially aligned with the z-axis of the x-y-z coordinate system.

[0042] In one embodiment, the continuous process involved in the method of fabricating the substrate 100 includes any one of 3D printing, stereolithography, light-based additive manufacturing, or digital light processing involving cross-linking of a dielectric material.

[0043] While certain combinations of individual features are described and illustrated herein, these combinations of certain features are for illustrative purposes only, and any combination of any of such individual features, whether or not such combination is explicitly illustrated, may be utilized in accordance with one embodiment and will be recognized as consistent with the disclosure herein. All such combinations of features as disclosed herein are contemplated herein and are considered to be within the scope of the invention as understood by those skilled in the art considering the entire application, and are considered to be within the scope of the invention disclosed herein to the extent that they fall within the scope of the invention as defined by the appended claims in a manner understood by those skilled in the art.

[0044] While the invention has been described herein with reference to example embodiments, it will be understood by those skilled in the art that various changes can be made without departing from the scope of the claims, and equivalents can be substituted for its elements. Many modifications can be made to adapt a particular situation or material to the teachings without departing from the essential scope of the invention. Therefore, it is intended that the invention not be limited to the specific embodiments disclosed herein as the best or only form contemplated for carrying out the invention, but rather that the invention include all embodiments falling within the scope of the appended claims. In the drawings and description, example embodiments may have been disclosed and specific terms and / or dimensions may have been utilized, but they are used only in a general, illustrative and / or descriptive sense and not for purposes of limitation, and the scope of the claims is not so limited. The use of terms such as first, second, etc. does not indicate any order or importance, but rather such terms as first, second, etc. are used to distinguish one element from another. The use of the words a, an, etc. does not indicate a limitation of quantity, but rather indicates the presence of at least one of the recited particulars. The term "comprising" as used herein does not exclude the possibility of including one or more additional features. And any background information provided herein is provided to clarify information that the applicant believes may be relevant to the invention disclosed herein. It is not necessarily intended, nor should it be construed, that any of such background information constitutes prior art to embodiments of the invention disclosed herein.

[0045] In view of all of the above, it will be appreciated that various aspects of the embodiments are disclosed herein and are admissible to, but not limited to, at least the following aspects and / or combinations of aspects.

[0046] Aspect 1: A substrate comprising a monolithic structure formed from a dielectric material having a first side, a second side, and an intermediate region between the first side and the second side, the intermediate region being a lattice structure of the dielectric material and comprising a plurality of interstitial spaces between the lattice-structured dielectric materials, the lattice structure extending between and being monolithically connected to the first side and the second side, and at least one of the first side and the second side comprising a substantially solid surface suitably configured to support one or more of electronic circuit imaging, electroplating, metal deposition, or vias between the first side and the second side.

[0047] Aspect 2: The substrate of aspect 1, wherein the interstitial spaces contain air.

[0048] Aspect 3: The substrate of aspect 1 or 2, wherein the monolithic structure is not a foamed material.

[0049] Aspect 4: The substrate of any one of aspects 1 to 3, wherein the monolithic structure is not a laminated structure.

[0050] Aspect 5: The substrate of any one of aspects 1 to 4, wherein both the first side and the second side comprise a substantially solid surface suitably configured to support one or more of electronic circuit imaging, electroplating, metal deposition, or vias between the first side and the second side.

[0051] Aspect 6: The substrate of any one of aspects 1 to 5, wherein the dielectric material of the monolithic structure has a relative dielectric constant of 1.01 or more and 5 or less.

[0052] Aspect 7: The substrate of aspect 6, wherein the dielectric material of the monolithic structure has a relative dielectric constant of 1.1 or more and 4.5 or less.

[0053] Aspect 8: The substrate of any one of aspects 1 to 7, wherein the monolithic structure is formed with respect to a rectangular x - y - z coordinate system in which the z - axis is perpendicular to both the first side and the second side, and the dielectric material comprises ceramic fibers substantially aligned in the x - y plane of the x - y - z coordinate system.

[0054] Aspect 9: A substrate according to any one of Aspects 1 to 7, wherein the monolithic structure is formed with respect to an orthogonal x-y-z coordinate system in which the z-axis is perpendicular to both the first side and the second side, and the dielectric material comprises ceramic fibers substantially aligned with the z-axis of the x-y-z coordinate system.

[0055] Aspect 10: A substrate according to any one of Aspects 1 to 7, wherein the monolithic structure is formed with respect to an orthogonal x-y-z coordinate system in which the z-axis is perpendicular to both the first side and the second side, the dielectric material comprises ceramic fibers substantially aligned with the x-y plane of the x-y-z coordinate system, and the dielectric material comprises ceramic fibers substantially aligned with the z-axis of the x-y-z coordinate system.

[0056] Aspect 11: A substrate according to any one of Aspects 1 to 10, wherein the monolithic structure comprises one or more vias extending between the first side and the second side.

[0057] Aspect 12: A substrate according to Aspect 11, wherein one or more vias comprise a conductive surface between the first side and the second side of the monolithic structure.

[0058] Aspect 13: A substrate according to any one of Aspects 1 to 12, wherein the lattice structure includes a gyroidal lattice structure.

[0059] Aspect 14: A substrate according to any one of Aspects 1 to 13, further comprising a metal coating layer on the first side, the second side, or both the first side and the second side of the monolithic structure.

[0060] Aspect 15: A substrate according to Aspect 14, further comprising a via, wherein the via comprises a conductive surface between the first side and the second side of the monolithic structure that is electrically connected to the metal coating layer on the first side, the second side, or both the first side and the second side.

[0061] Aspect 16: A substrate according to any one of Aspects 1 to 15, wherein the lattice structure is a face-based lattice structure and not a strut-based lattice structure.

[0062] Aspect 17: A substrate according to any one of Aspects 1 to 16, wherein the lattice structure in the intermediate region has a uniform distribution of dielectric material and interstitial spaces.

[0063] Aspect 18: A substrate according to any one of Aspects 1 to 17, wherein the first side is planar, the second side is planar, and the second side is parallel to the first side.

[0064] Aspect 19: A substrate according to any one of Aspects 1 to 17, wherein the first side is provided equidistant from the second side.

[0065] Aspect 20: The substrate of Aspect 19, wherein the first side and the second side are curved.

[0066] Aspect 21: A substrate according to any one of Aspects 1 to 20, wherein the monolithic structure is formed with respect to an orthogonal x - y - z coordinate system in which the z - axis is perpendicular to both the first side and the second side, the substrate operates at a given frequency f having an operating wavelength λ, and the total thickness of the substrate in the z - direction is λ / 2 or less.

[0067] Aspect 22: The substrate of Aspect 21, wherein the monolithic structure is formed with respect to an orthogonal x - y - z coordinate system in which the z - axis is perpendicular to both the first side and the second side, the substrate operates at a given frequency f having an operating wavelength λ, and the total thickness of the substrate in the z - direction is λ / 4 or less.

[0068] Aspect 23: A multilayer assembly comprising two or more substrates according to any one of Aspects 1 to 22, each of the substrates being mechanically attached, adhered, or fused to one of the adjacent substrates.

[0069] Aspect 24: The assembly of Aspect 23, wherein each of the substrates comprises one or more mechanical alignment functions that mechanically attach and engage with corresponding ones of the mechanical alignment functions of one of the adjacent substrates.

[0070] Aspect 25: The assembly of Aspect 24, wherein the one or more mechanical alignment functions and the corresponding ones of the mechanical alignment functions include an elastically deformable interference fit therebetween.

[0071] Aspect 26: An assembly according to any one of Aspects 23 to 25, wherein the monolithic structure is formed with respect to an orthogonal x-y-z coordinate system in which the z-axis is perpendicular to both the first side and the second side, the assembly operates at a predetermined frequency f having an operating wavelength λ, and the total thickness of the assembly in the z-direction is λ / 2 or less.

[0072] Aspect 27: An assembly according to any one of Aspects 23 to 25, wherein the monolithic structure is formed with respect to an orthogonal x-y-z coordinate system in which the z-axis is perpendicular to both the first side and the second side, the assembly operates at a predetermined frequency f having an operating wavelength λ, and the total thickness of the assembly in the z-direction is λ / 4 or less.

[0073] Aspect 28: A method of fabricating a substrate having a monolithic structure according to any one of Aspects 1 to 22, the method including, in a continuous process, forming a first side of the substrate, and, via the continuous process, monolithically forming an intermediate region of the substrate on the first side, the intermediate region being a lattice structure of a dielectric material and having a plurality of gap spaces between the dielectric materials of the lattice structure, and, via the continuous process, monolithically forming a second side of the substrate on the intermediate region.

[0074] Aspect 29: The method of Aspect 28, wherein the continuous process further includes forming one or more vias extending from the first side, through the intermediate region, to the second side.

[0075] Aspect 30: The method of Aspect 28 or 29, further including imaging an electronic circuit network on at least one of the first side and the second side to provide electronic circuit imaging.

[0076] Aspect 31: The method of Aspect 28 or 29, further including metallizing an electronic circuit network on at least one of the first side and the second side to provide electronic circuit imaging.

[0077] Aspect 32: The monolithic structure is formed with respect to an orthogonal x-y-z coordinate system in which the z-axis is perpendicular to both the first side and the second side, and the method further includes the step of forming ceramic fibers substantially aligned with the x-y plane of the x-y-z coordinate system within the dielectric material via a continuous process, the method of any one of Aspects 28 to 31.

[0078] Aspect 33: The monolithic structure is formed with respect to an orthogonal x-y-z coordinate system in which the z-axis is perpendicular to both the first side and the second side, and the method further includes the step of forming ceramic fibers substantially aligned with the z-axis of the x-y-z coordinate system within the dielectric material via a continuous process, the method of any one of Aspects 28 to 31.

[0079] Aspect 34: The monolithic structure is formed with respect to an orthogonal x-y-z coordinate system in which the z-axis is perpendicular to both the first side and the second side, and the method further includes the step of forming ceramic fibers substantially aligned with the x-y plane of the x-y-z coordinate system within the dielectric material via a continuous process and the step of forming ceramic fibers substantially aligned with the z-axis of the x-y-z coordinate system within the dielectric material via a continuous process, the method of any one of Aspects 28 to 31.

[0080] Aspect 35: The continuous process includes any one of 3D printing, stereolithography, light-based additive manufacturing, or digital light processing involving cross-linking of the dielectric material, the method of any one of Aspects 28 to 34.

Explanation of Reference Numerals

[0081] 100, 100.1, 100.2 Substrate 102 Monolithic Structure 104 Via 150, 160 Ceramic Fibers 200 First Side 202, 302 Substantially Solid Surface 250 Metal Deposition 252 Trace Line 300 Second Side 400 Intermediate Region 402 Gap space 403 Lattice structure 500 Multilayer assembly 502 Ellipsis 504 Mechanical attachment structure 506 Adhesive 508 Fusion interface 510 Elastically deformable protrusion 515 Elastically deformable recess

Claims

1. A substrate comprising a monolithic structure formed from a dielectric material having a first side, a second side, and an intermediate region between the first side and the second side, wherein the intermediate region comprises a lattice structure of the dielectric material, the lattice structure comprising a plurality of interstitial spaces between the dielectric materials of the lattice structure, the lattice structure extending between and being monolithically connected to the first side and the second side, wherein at least one of the first side and the second side comprises a substantially solid surface suitably configured to support one or more of electronic circuit imaging, electroplating, metal deposition, or vias between the first side and the second side.

2. The substrate of claim 1, wherein the interstitial spaces contain air.

3. The substrate of claim 1 or 2, wherein the monolithic structure is not a foamed material.

4. The substrate according to any one of claims 1 to 3, wherein the monolithic structure is not a laminated structure.

5. The substrate according to any one of claims 1 to 4, wherein both the first side and the second side comprise a substantially solid surface suitably configured to support one or more of electronic circuit imaging, electroplating, metal deposition, or vias between the first side and the second side.

6. The substrate according to any one of claims 1 to 5, wherein the dielectric material of the monolithic structure has a relative dielectric constant of 1.01 or more and 5 or less.

7. The substrate of claim 6, wherein the dielectric material of the monolithic structure has a relative dielectric constant of 1.1 or more and 4.5 or less.

8. The monolithic structure is formed with respect to an orthogonal x - y - z coordinate system in which the z - axis is perpendicular to both the first side and the second side, and the dielectric material comprises ceramic fibers substantially aligned with the x - y plane of the x - y - z coordinate system. The substrate according to any one of claims 1 to 7.

9. The monolithic structure is formed with respect to an orthogonal x - y - z coordinate system in which the z - axis is perpendicular to both the first side and the second side, and the dielectric material comprises ceramic fibers substantially aligned with the z - axis of the x - y - z coordinate system. The substrate according to any one of claims 1 to 7.

10. The monolithic structure is formed with respect to an orthogonal x - y - z coordinate system in which the z - axis is perpendicular to both the first side and the second side, The dielectric material comprises ceramic fibers substantially aligned in the x-y plane of the x-y-z coordinate system. The substrate according to any one of claims 1 to 7, wherein the dielectric material comprises ceramic fibers substantially aligned along the z-axis of the x-y-z coordinate system. **Claim 11** The substrate according to any one of claims 1 to 10, wherein the monolithic structure comprises one or more vias extending between the first side and the second side. **Claim 12** The substrate according to claim 11, wherein the one or more vias comprise a conductive surface between the first side and the second side of the monolithic structure. **Claim 13** The substrate according to any one of claims 1 to 12, wherein the lattice structure comprises a gyroidal lattice structure. **Claim 14** The substrate according to any one of claims 1 to 13, further comprising a metal coating layer on the first side, the second side, or both the first side and the second side of the monolithic structure. **Claim 15** Further comprising vias, The substrate according to claim 14, wherein the vias comprise a conductive surface between the first side and the second side of the monolithic structure that is electrically connected to the metal coating layer on the first side, the second side, or both the first side and the second side. **Claim 16** The substrate according to any one of claims 1 to 15, wherein the lattice structure is a face-based lattice structure and not a strut-based lattice structure. **Claim 17** The substrate according to any one of claims 1 to 16, wherein the lattice structure in the intermediate region has a uniform distribution of the dielectric material and the interstitial space. **Claim 18** The substrate according to any one of claims 1 to 17, wherein the first side is planar, the second side is planar, and the second side is parallel to the first side. **Claim 19** The substrate according to any one of claims 1 to 17, wherein the first side is provided at an equal distance from the second side. **Claim 20** The substrate according to claim 19, wherein the first side and the second side are curved. **Claim 21** The monolithic structure is formed with respect to an orthogonal x-y-z coordinate system in which the z-axis is perpendicular to both the first side and the second side. The substrate according to any one of claims 1 to 20, wherein the substrate operates at a given frequency f having an operating wavelength λ, and the total thickness of the substrate in the z direction is λ / 2 or less. **Claim 22** The monolithic structure is formed with respect to an orthogonal x - y - z coordinate system in which the z - axis is perpendicular to both the first side and the second side. The substrate according to claim 21, wherein the substrate operates at a predetermined frequency f having an operating wavelength λ, and the total thickness of the substrate in the z - direction is λ / 4 or less.

23. A multilayer assembly comprising two or more substrates according to any one of claims 1 to 22, wherein each of the substrates is mechanically attached to, adhered to, or fused to one of the adjacent substrates.

24. The assembly according to claim 23, wherein each of the substrates comprises one or more mechanical alignment functions that mechanically attach to and engage corresponding ones of the mechanical alignment functions of one of the adjacent substrates.

25. The assembly according to claim 24, wherein the one or more mechanical alignment functions and the corresponding ones of the mechanical alignment functions include an elastically deformable interference fit therebetween.

26. The monolithic structure is formed with respect to an orthogonal x - y - z coordinate system in which the z - axis is perpendicular to both the first side and the second side. The assembly according to any one of claims 23 to 25, wherein the assembly operates at a predetermined frequency f having an operating wavelength λ, and the total thickness of the assembly in the z - direction is λ / 2 or less.

27. The monolithic structure is formed with respect to an orthogonal x - y - z coordinate system in which the z - axis is perpendicular to both the first side and the second side. The assembly according to any one of claims 23 to 25, wherein the assembly operates at a predetermined frequency f having an operating wavelength λ, and the total thickness of the assembly in the z - direction is λ / 4 or less.

28. A method of fabricating a substrate having a monolithic structure according to any one of claims 1 to 22, comprising forming the first side of the substrate in a continuous process; forming the intermediate region of the substrate monolithically thereon via the continuous process, the intermediate region being the lattice structure of the dielectric material and having the plurality of interstitial spaces between the dielectric materials of the lattice structure; and forming the second side of the substrate monolithically thereon via the continuous process over the intermediate region.

29. The method of claim 28, wherein the continuous process further comprises forming one or more vias extending from the first side, through the intermediate region, to the second side.

30. The method of claim 28 or 29, further comprising imaging an electronic circuit network on at least one of the first side and the second side to provide an electronic circuit image.

31. The method of claim 28 or 29, further comprising metallizing an electronic circuit network on at least one of the first side and the second side to provide an electronic circuit image.

32. The monolithic structure is formed with respect to an orthogonal x - y - z coordinate system in which the z - axis is perpendicular to both the first side and the second side, and the method The method of any one of claims 28 to 31, further comprising forming ceramic fibers substantially aligned with the x - y plane of the x - y - z coordinate system within the dielectric material via the continuous process.

33. The monolithic structure is formed with respect to an orthogonal x - y - z coordinate system in which the z - axis is perpendicular to both the first side and the second side, and the method The method of any one of claims 28 to 31, further comprising forming ceramic fibers substantially aligned with the z - axis of the x - y - z coordinate system within the dielectric material via the continuous process.

34. The monolithic structure is formed with respect to an orthogonal x - y - z coordinate system in which the z - axis is perpendicular to both the first side and the second side, and the method The method of any one of claims 28 to 31, further comprising: forming, via the continuous process, ceramic fibers substantially aligned with the x - y plane of the x - y - z coordinate system within the dielectric material; and forming, via the continuous process, ceramic fibers substantially aligned with the z - axis of the x - y - z coordinate system within the dielectric material.

35. The method of any one of claims 28 to 34, wherein the continuous process comprises any one of 3D printing, stereolithography, light - based additive manufacturing, or digital light processing involving cross - linking of the dielectric material.

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