Patent Application
20150295300
This invention generally relates to wave guides for high frequency signals, and in particular to waveguides with dielectric cores.
In electromagnetic and communications engineering, the term waveguide may refer to any linear structure that conveys electromagnetic waves between its endpoints. The original and most common meaning is a hollow metal pipe used to carry radio waves. This type of waveguide is used as a transmission line for such purposes as connecting microwave transmitters and receivers to their antennas, in equipment such as microwave ovens, radar sets, satellite communications, and microwave radio links.
A dielectric waveguide employs a solid dielectric core rather than a hollow pipe. A dielectric is an electrical insulator that can be polarized by an applied electric field. When a dielectric is placed in an electric field, electric charges do not flow through the material as they do in a conductor, but only slightly shift from their average equilibrium positions causing dielectric polarization. Because of dielectric polarization, positive charges are displaced toward the field and negative charges shift in the opposite direction. This creates an internal electric field which reduces the overall field within the dielectric itself. If a dielectric is composed of weakly bonded molecules, those molecules not only become polarized, but also reorient so that their symmetry axis aligns to the field. While the term “insulator” implies low electrical conduction, “dielectric” is typically used to describe materials with a high polarizability; which is expressed by a number called the relative permittivity (∈k). The term insulator is generally used to indicate electrical obstruction while the term dielectric is used to indicate the energy storing capacity of the material by means of polarization.
Permittivity is a material property that expresses a measure of the energy storage per unit meter of a material due to electric polarization (J/V̂2)/(m). Relative permittivity is the factor by which the electric field between the charges is decreased or increased relative to vacuum. Permittivity is typically represented by the Greek letter ∈. Relative permittivity is also commonly known as dielectric constant.
Permeability is the measure of the ability of a material to support the formation of a magnetic field within itself in response to an applied magnetic field. Magnetic permeability is typically represented by the Greek letter μ.
The electromagnetic waves in a metal-pipe waveguide may be imagined as travelling down the guide in a zig-zag path, being repeatedly reflected between opposite walls of the guide. For the particular case of a rectangular waveguide, it is possible to base an exact analysis on this view. Propagation in a dielectric waveguide may be viewed in the same way, with the waves confined to the dielectric by total internal reflection at its surface.
Particular embodiments in accordance with the invention will now be described, by way of example only, and with reference to the accompanying drawings:
Other features of the present embodiments will be apparent from the accompanying drawings and from the detailed description that follows.
Specific embodiments of the invention will now be described in detail with reference to the accompanying figures. Like elements in the various figures are denoted by like reference numerals for consistency. In the following detailed description of embodiments of the invention, numerous specific details are set forth in order to provide a more thorough understanding of the invention. However, it will be apparent to one of ordinary skill in the art that the invention may be practiced without these specific details. In other instances, well-known features have not been described in detail to avoid unnecessarily complicating the description.
A dielectric waveguide (DWG) may be used as an interconnect to communicate chip to chip in a system or system to system, for example. As a signal propagates through a DWG, it may undergo magnitude and/or velocity changes due to the frequency response effects of frequency sensitive dielectric materials used to fabricate the DWG. While the signal may be “digital” in nature or be a continuous signal modulated to carry digital information, a digital signal may be represented and analyzed as a set of frequencies. Filter blocks or other periodic structures may be integrated into the DWG to control the frequency response of a DWG interconnect system, as will be described in more detail below.
As frequencies in electronic components and systems increase, the wavelength decreases in a corresponding manner. For example, many computer processors now operate in the gigahertz realm. As operating frequencies increase sub-terahertz, the wavelengths become short enough that signal lines that exceed a short distance may act as an antenna and signal radiation may occur.
Waves in open space propagate in all directions, as spherical waves. In this way they lose their power proportionally to the square of the distance; that is, at a distance R from the source, the power is the source power divided by R2. A wave guide may be used to transport high frequency signals over relatively long distances. The waveguide confines the wave to propagation in one dimension, so that under ideal conditions the wave loses no power while propagating. Electromagnetic wave propagation along the axis of the waveguide is described by the wave equation, which is derived from Maxwell's equations, and where the wavelength depends upon the structure of the waveguide, and the material within it (air, plastic, vacuum, etc.), as well as on the frequency of the wave. Commonly-used waveguides are only of a few categories. The most common kind of waveguide is one that has a rectangular cross-section, one that is usually not square. It is common for the long side of this cross-section to be twice as long as its short side. These are useful for carrying electromagnetic waves that are horizontally or vertically polarized.
A waveguide configuration may have a core member made from dielectric material with a high dielectric constant and be surrounded with a cladding made from dielectric material with a lower dielectric constant. While theoretically, air could be used in place of the cladding, since air has a dielectric constant of approximately 1.0, any contact by humans, or other objects may introduce serious impedance mismatch effects that may result in signal loss or corruption. Therefore, typically free air does not provide a suitable cladding.
For the exceedingly small wavelengths encountered for sub-THz radio frequency (RF) signals, dielectric waveguides perform well and are much less expensive to fabricate than hollow metal waveguides. Furthermore, a metallic waveguide has a frequency cutoff determined by the size of the waveguide. Below the cutoff frequency there is no propagation of the electromagnetic field. Dielectric waveguides may have a wider range of operation without a fixed cutoff point. However, a purely dielectric waveguide may be subject to interference caused by touching by fingers or hands, or by other conductive objects. Metallic waveguides confine all fields and therefore do not suffer from EMI (electromagnetic interference) and cross-talk issues; therefore, a dielectric waveguide with a metallic cladding may provide significant isolation from external sources of interference. Various types of dielectric core waveguides will be described in more detail below.
Various configurations of dielectric waveguides (DWG) and interconnect schemes are described in US Patent Publication number 2014-0287701, filed Apr. 1, 2013, entitled “Integrated Circuit with Dipole Antenna Interface for Dielectric Waveguide” by Juan Herbsommer, et al, and are incorporated by reference herein. Various antenna configurations for launching and receiving radio frequency signals to/from a DWG are also described therein and are incorporated by reference herein.
As used herein, the term “periodic structure” refers to a structure that includes multiple elements that are spaced apart with approximately equal spacing. Typically, the spacing will be related to a wavelength of a signal with a selected frequency or range of frequencies that is intended to be affected by the periodic structure. A periodic structure is a single unit cell repeated in the x-y-z direction with some spacing. The structure may be repeated the entire length of the waveguide for cases where it is useful to affect the entire waveguide, or in specific places, such as at a bend, to help contain the fields or filter higher order modes caused by the bend, for example.
DWG periodic structure 240 has a first DWG portion 243, a second DWG portion 244, and one or more filter stubs 245. A signal propagating through DWG in either direction will pass through filter structure 240. In this example, DWG 200 and filter stubs 245 have a core made from a polymer dielectric material having a first dielectric constant ∈1 and a polymer cladding having dielectric constant ∈2, where ∈1>∈2. A metallic or other type of conductive coating 246 surrounds DWG filter structure 240.
One or more copies of metallic filter structure 240 may be integrated along the dielectric waveguide 200 to modify the frequency and dispersion characteristics of the dielectric waveguide interconnect. In this example, the length and position of the stubs determine the frequency characteristic of the interconnect. The ends of the stubs are blanked off to short-circuit them and thereby cause a boundary condition in which the electric field is zero. When the short-circuited stubs are odd multiples of approximately λ/4 long, then the field will be at a maximum in the waveguide core and the filter will be a band-pass filter, where λ represents the approximate wavelength of a target range of frequencies. When the stubs are odd multiples of approximately λ/2 long the filter will be a band-stop filter. The number of stubs affects the quality factor of the filter and the raw frequencies that are affected by the filter. The stubs are spaced to form a periodic structure with spacing typically in a range of λ/2-λ/8, for example.
As an electromagnetic (EM) signal wave propagates through filter structure 240, some signal energy may divert into the one or more filter stubs 245, depending on the wavelength of the EM signal and the physical dimensions of filter stubs 245. Reflected signal energy from filter stubs 245 may combine with the original EM signal in a constructive or destructive manner, depending on the physical size of filters stubs 245 and the EM signal frequency. In this manner, various types of high pass, low pass, band pass, band block, etc., filters may be constructed.
In this example, a periodic metallic element 440 embedded in a dielectric waveguide is formed on a substrate 420 onto which the waveguide with periodic metallic structure can be printed, as illustrated in step 401. This substrate may range from a die, package, or board, or to a substrate as simple as paper, for example.
Various layers of printed metal 430, 414 and dielectric material 410, 412 form the core of the waveguide and the walls of the metallic structure. In step 402, a conductive layer is printed to form the conductive bottom layer of periodic structure 440. Conductive layer 430 may be metallic or may be a conductive non-metallic material, for example. The printed dielectric deposited in step 403 may be composed of any insulating material which can be deposited in thick layers (polymers, oxides). The dielectric material may be deposited as a single bulk material with relative permittivity ∈r1 and relative permeability μr1, or in multiple layers to form a graded-permittivity/permeability core with relative permittivities/permeability of ∈r1-∈m, μr1-μrn. The grading may be attained via use of different materials, or nanoparticle doping, for example. A top layer of conductive material is deposited in step 404 to complete periodic structure 440.
In this manner, a printed metallic periodic structure may be processed during the waveguide fabrication to embed the element directly within the DWG. A printed metallic shell may totally surround the periodic structure and provide improved isolation, as compared to a dielectric only implementation. As illustrated in
EM signals propagating through a DWG may undergo changes in both amplitude and velocity. The magnitude may vary over a range of frequencies due to signal attenuation and dispersion, which may lead to changes in the power vs. frequency characteristic of a signal as it propagates through a DWG transmission system. Similarly, an EM signal may undergo changes in group velocity vs. freq which may affect phase relationships as a signal propagates through a DWG transmission system due to frequency dependent permittivity characteristics of the dielectric core, for example.
Periodic filtering structures may be fabricated to tailor the magnitude transmission response in several ways, such as by providing a bandstop for a particular frequency or range of frequencies, by providing a bandpass for particular frequency or range of frequencies, etc., for example. Similarly, periodic filtering structures may be fabricated to correct for phase changes in a signal due to dielectric material effects.
A wide array of other configurations of periodic metallic or non-metallic periodic structures may be used to control the dispersion and frequency characteristics of a dielectric waveguide interconnect. Additional examples are illustrated later in this disclosure.
Several configurations of dielectric waveguides and integrated periodic structures and methods for making them will now be described in more detail. In each example, periodic structures may be formed as part of the waveguide as described above.
In this example, dielectric clad DWG 500 is fabricated on a surface 522 of a substrate 520, as will be explained in more detail below. This substrate may range from an integrated circuit (IC) die, a substrate in a multi-chip package, a printed circuit board (PCB) on which several ICs are mounted, etc., for example. The substrate may be any commonly used or later developed material used for electronic systems and packages, such as: silicon, ceramic, Plexiglas, fiberglass, plastic, metal, etc., for example. The substrate may be as simple as paper, for example.
In this example, metallic clad DWG 600 is fabricated on a surface 622 of a substrate 620. This substrate may range from an integrated circuit (IC) die, a substrate in a multi-chip package, a printed circuit board (PCB) on which several ICs are mounted, etc., for example. The substrate may be any commonly used or later developed material used for electronic systems and packages, such as: silicon, ceramic, Plexiglas, fiberglass, plastic, metal, etc., for example. The substrate may be as simple as paper, for example.
In this example, metallic clad DWG 700 is fabricated on a surface 722 of a substrate 720. This substrate may range from an integrated circuit (IC) die, a substrate in a multi-chip package, a printed circuit board (PCB) on which several ICs are mounted, etc., for example. The substrate may be any commonly used or later developed material used for electronic systems and packages, such as: silicon, ceramic, Plexiglas, fiberglass, plastic, metal, etc., for example. The substrate may be as simple as paper, for example.
For a metallic clad waveguide, such as those illustrated in
Embodiments of the invention may be implemented using any of the dielectric core waveguides described above, for example. In each embodiment, one or more periodic filter structures may be embedded in the DWG to perform EM signal filtering as described above in more detail.
The various dielectric core waveguide configurations described above may be fabricated using a printing process, such as an inkjet printer or other three dimensional printing mechanism. Fabrication of three dimensional structures using ink jet printers or similar printers that can “print” various polymer materials is well known and need not be described in further detail herein. For example, see “3D printing,” Wikipedia, Sep. 4, 2014. Printing allows for the rapid and low-cost deposition of thick dielectric and metallic layers, such as 0.1 um-1000 um thick, for example, while also allowing for fine feature sizes, such as 20 um feature sizes, for example. Standard integrated circuit (IC) fabrication processes are not able to process layers this thick. Standard macroscopic techniques, such as machining and etching, typically used to manufacture dielectric waveguides and metallic structures may only allow feature sizes down to 1 mm, for example. These thicker printed dielectric and metallic layers on the order of 100 nm-1 mm which are made possible by inkjet printing enable waveguide operation at Sub-THz and THz frequencies. Previously optical frequencies could be handled using standard semiconductor fabrication methods while lower frequencies may be handled using large metallic waveguides; however, there was a gap in technology for fabricating waveguides for THz signals. Printing the waveguides directly onto the chip/package/board mitigates alignment errors of standard waveguide assemblies and simplifies the packaging process.
In another embodiment, bottom layer 930 may be pre-fabricated on the substrate; for example, it may be a conductive layer that is laminated on the surface of substrate 920. In this example, unneeded portions of the conductive layer may be removed by etching, for example, or by other known fabrication techniques for creating patterned features on a substrate. In another embodiment, bottom layer 930 may be formed by diffusion of a layer onto substrate 920, or by sputtering a layer onto substrate 920, or by flooding the surface of substrate 920 with a liquid or paste, etc., for example. In another embodiment, a stamped metal or dielectric shape may be laminated or otherwise affixed to substrate 920 to form bottom layer 930
In process step 902, a core member 912 is formed by printing a dielectric material to form the core of the waveguide. Multiple passes of print-head 952 may be required to obtain a desired thickness for core 912. The printed dielectric may be composed of any dielectric material which can be deposited in thick layers, such as polymers, oxides, etc., for example.
During process step 903, a conformal cladding coating is applied by print-head 953 to cover the top and sides of the waveguide. In this manner, core 912 is enclosed with a conductive cladding 910 or a dielectric cladding to form a waveguide. Various conductive materials that can be printed in this manner may be used to form coating 910, such as: a conductive ink with metallic filler, a conductive polymer formed by ionic doping, carbon and graphite based compounds, conductive oxides, etc., for example. Similarly, a dielectric material similar to base layer 930 may be used to form the cladding for a non-conductive DWG, for example.
During process step 1003, the core 1012 is formed by print-head 1053 using a dielectric material that has a different dielectric constant than the material used for layer 1010. Then, in step 1004 another layer 1011 of dielectric material is applied by print-head 1054 to complete the cladding of the waveguide.
Multiple passes of print-head 1053 may be required to obtain a desired thickness for core 1012. The printed dielectric may be composed of any dielectric material which can be deposited in thick layers, such as polymers, oxides, etc., for example. Additional passes of print-head 1053 may be performed to form a periodic structure such as structure 240, 440, referring back to
In another embodiment, additional layers may be used to form graded core member 1012 using a range of relative permittivity of ∈r1-∈rn, for example.
During process step 1005, a printed conductive coating is applied by print-head 1055 to cover the top and sides of the periodic structure. In this manner, a periodic structure such as 240, 440 is enclosed with a conductive cladding 1014, as discussed in more detail above.
The same steps that are used to form the periodic structure may also be used to form the rest of the DWG. Similarly, conductive gladding may be formed in other regions of the DWG besides the periodic structure.
For all of the waveguide embodiments described above, the waveguides may be printed arbitrarily long in a desired pattern in the plane of the substrate. However, the length of the DWG may be limited by the “attenuation budget” available since the transceiver must allow for a determined attenuation of the signal between TX and RX. The maximum length of the DWG depends on several factors, including: the material of the DWG, its attenuation, isolation properties bending loss and number of curves, etc., for example.
Printed waveguides may conform to the surface topology of the substrate. If the substrate is flexible, the waveguide may also be flexible as long as the materials used to print the waveguide are also flexible.
In another embodiment, the dielectric core may be formed in a such a manner that the dielectric core has a dielectric constant value that varies over at least two values along the longitudinal extent of the dielectric core. This may be done by printing different materials along the extent of the dielectric core, for example. This may be useful for matching impedance of the waveguide to another waveguide, for example.
Typically, using a lithographic process to form the dielectric core would produce essentially vertical sidewalls on the dielectric core. Deposition of a metallic material to cover the dielectric core may be difficult when the sides of the dielectric core are vertical. However, using an inkjet process to form the dielectric core and controlling the surface tension of the ink allows the slope, or angle, of the sidewalls of the printed waveguide to be controlled. Thus, the sidewalls of the dielectric core may be formed with a slight inward slope, or may be formed perfectly vertical, depending on the needs of the next processing step. In this manner, deposition of the metallic sidewalls may be improved. This may not be an issue in other 3D printing processes, however.
One or more periodic structures 1140-1143 may be included to provide signal compensation by passing or rejecting a particular signal frequency or range of frequencies, as discussed above in more detail. Periodic structures 1140-1141 are placed at a corner region of DWG 1162 in order to compensate for corner effects, for example. Periodic structures may be spaced along the length of DWG 1162 in an even spacing manner, or the spacing between each periodic structure may vary, as needed to perform signal compensation or to perform other functions, for example.
As described in more detail above, waveguides 1161, 1162 and periodic structures 1140-1143 may be formed directly on the surface of substrate 1120 using an inkjet process or other form of 3D printing. This process allows the wave guides to be formed on a chip die of each node and to then follow over the edge of each die an onto the surface of substrate 1120. In a similar manner, one waveguide, such as 1162, may be routed over the top of another waveguide, such as 1161, as indicated at 1171, for example.
In some embodiments, substrate 1120 may be a single integrated circuit that includes multiple functional nodes in a single SoC. In that case, the SoC may include an antenna or other coupling structure in each node such as node 1101-1104, with one or more DWGs coupled between the two nodes formed directly on the SoC substrate. In this manner, a wide degree a freedom is available to route multiple waveguides on a surface of the substrate, and to cross over other waveguides or other physical features that are present on the surface of the substrate.
As shown by the above descriptions and examples, multiple electronic devices may be easily interconnected to provide sub-terahertz communication paths between the electronic devices by using the techniques described herein.
Printable metallic waveguides on top of a chip, package, or board may be processed onto nearly any substrate (silicon, Plexiglas, plastic, paper, etc. . . . ). Printed dielectric layers on the order of 100 nm-1 mm which are made possible by inkjet printing enable waveguide operation at Sub-THz frequencies; previously only optical frequencies could be reached using standard fabrication methods. A metallic or otherwise conductive shell provides isolation over standard dielectric waveguides.
Thus, extremely low-cost and low-loss sub-THz signal routing waveguides may be printed onto nearly any substrate. Printing the waveguides directly onto the chip/package/board mitigates alignment errors of standard waveguide assemblies and simplifies the packaging process.
As described above, while propagating through the DWG, the signal may undergo magnitude and phase distortion due to frequency dependent transmission characteristics of the dielectric material used to form the DWG.
The set of RF signals may be filtered 1204 with one or more periodic structures embedded within the DWG such that a core of the DWG is integral to the periodic structures, as described in more detail above, such as periodic structures 240, 440, for example. This filtering may compensate for magnitude and phase distortion experience by the signal as it propagates through the DWG. The periodic structures may attenuate one or more selected frequencies, for example.
The filtered set of RF signals may be provided 1206 to a receiver circuit coupled to the DWG. In this manner, magnitude distortion and/or phase distortion of the digital signal while propagating through the DWG may be minimized.
Periodic filtering structures may be fabricated as described above in more detail to tailor the magnitude transmission response in several ways, such as by providing a bandstop for a particular frequency or range of frequencies, by providing a bandpass for particular frequency or range of frequencies, etc., for example. Similarly, periodic filtering structures may be fabricated to correct for phase changes in a signal due to dielectric material effects.
In some embodiments, biasing the ferro/para material (electric or magnetic field) allows for tuning of the periodic structures which can be used for shifting the filtering frequency, modulating, isolating (unidirectional propagation in the case of the ferromagnetic materials), etc., for example.
In addition to band pass or band stop filters, a periodic structure may perform other functions, such as: phase shifting, filtering, isolation (one directional propagation), tunable filtering, modulation (amplitude or phase), adaptive matching, etc., for example.
For adaptive matching, a periodic structure may be put at the input/output ends of a waveguide. Typically the transmitters and receivers have a variable input/output impedance which is dependent on the power level. By including tunable materials within the periodic structures, impedance matching may be adaptively optimized based on the power going through the waveguide, for example.
The embedded elements can also be polarization sensitive so if a signal is sent through the waveguide which has multiple polarizations, the elements may be sensitized to act on only one or several of the polarizations.
It is known that the dielectric constant of several high dielectric constant materials may change in the presence of a DC electric field. Tunable dielectric materials are materials whose permittivity (more commonly called dielectric constant) can be varied by varying the strength of an electric field to which the materials are subjected. Even though these materials work in their paraelectric phase above the Curie temperature, they are conveniently called “ferroelectric” because they exhibit spontaneous polarization at temperatures below the Curie temperature. Tunable ferroelectric materials including barium-strontium titanate (BST) or BST composites have been reported. Strontium titanate may be used at low temperatures.
This technique may be applied to any of the periodic structures described above, for example. In this example, device 1640 is fabricated on a substrate 1620, which may be flexible or rigid in different embodiments. An electrode 1650 may be formed on a surface 1622 of substrate 1620. A matching electrode 1651 may be formed on the top of DWG portion 1632. The electrodes 1650, 1651 may cover a portion or most of the DWG portion 1632. In another embodiment, the matching electrodes may be formed on the sides of DWG portion 1632, rather than on the top and bottom, for example.
Dielectric core material 1612 is a tunable high dielectric material, such as BST, Zinc oxide (ZnO), etc., for example. Alternatively, dielectric core material 1612 may be a polymer that is doped with high dielectric particles, such as BST, ZnO, etc., for example. The particles may be nm or um sized, for example. A variable voltage source 1652 may be connected across electrodes 1650, 1651 and used to tune the dielectric constant value of core material 1612 and to thereby tune the filter characteristics of filter 1600. Control logic may be coupled to the variable voltage source to control tuning of device 1600.
In another embodiment, a variable magnetic field may be applied in place of a variable electric field to provide tuning of a periodic structure.
In this manner, an array of metallic, dielectric, or magnetic shapes may be organized as a lattice within a waveguide to form a periodic structure that may provide several types of desired effects. Within a given DWG, two or more types of periodic structures may be embedded to provide multiple functions, for example. In some embodiments, an electrical or magnetic field may be used to tune the operation of the periodic structure.
While the invention has been described with reference to illustrative embodiments, this description is not intended to be construed in a limiting sense. Various other embodiments of the invention will be apparent to persons skilled in the art upon reference to this description. For example, while a dielectric waveguide has been described herein, another embodiment may use a metallic or non-metallic conductive material to form the top, bottom, and sidewalls of the wave guide, such as: a conductive polymer formed by ionic doping, carbon and graphite based compounds, conductive oxides, etc., for example. As used herein, the term “conductive waveguide” refers to a waveguide having either metallic or non-metallic conductive sidewalls.
While waveguides with polymer dielectric cores have been described herein, other embodiments may use other materials for the dielectric core, such as ceramics, glass, etc., for example.
A DWG may include a single periodic structure. In another embodiment, periodic structures may be integrated along a DWG in an evenly spaced manner, or they may be positioned with variable spacing, depending on the function of the periodic structures.
In some embodiments, a ferroelectric material may be printed in conjunction with a polymeric dielectric or in place of a polymeric dielectric to form a dielectric core that permits EM signal propagation in one direction through the DWG, but blocks propagation in the other direction.
The substrate on which a dielectric core waveguide is formed may be rigid or flexible, planar or non-planar, smooth or irregular, etc., for example. Regardless of the topology of the substrate, the dielectric core waveguide may be formed on the surface of the substrate and conform to the topology of the surface by using the additive processes described herein.
While dielectric cores with a rectangular cross section are described herein, other embodiments may be easily implemented using the printing processes described herein. For example, the dielectric core may have a cross section that is rectangular, square, trapezoidal, cylindrical, oval, or many other selected geometries. Furthermore, the processes described herein allow the cross section of a dielectric core to change along the length of a waveguide in order to adjust impedance, produce transmission mode reshaping, etc., for example.
In some embodiments, the substrate may be removed after forming a waveguide using the inkjet printing or other 3d printing process by dissolving the substrate with an appropriate solvent or melting a heat sensitive substrate, for example. In this manner, a free standing waveguide that may have a complicated shape may be formed using the ease of fabrication and optional material variations available as described herein.
The dielectric core of the conductive waveguide may be selected from a range of approximately 2.4-12, for example. These values are for commonly available dielectric materials. Dielectric materials having higher or lower values may be used when they become available.
While formation of a conductive waveguide by directly printing the waveguide onto the substrate using a layer-by-layer additive fabrication technique such as inkjet-printing is described herein, other additive techniques such as screen-printing, flexographic printing, or 3D printing may also be used.
While DWGs and metallic or otherwise conductive waveguides are described herein, the inkjet and 3D printing techniques described herein may also be used to form other forms of waveguides, micro-coax, etc., for example that conform to a surface of a substrate.
Certain terms are used throughout the description and the claims to refer to particular system components. As one skilled in the art will appreciate, components in digital systems may be referred to by different names and/or may be combined in ways not shown herein without departing from the described functionality. This document does not intend to distinguish between components that differ in name but not function. In the following discussion and in the claims, the terms “including” and “comprising” are used in an open-ended fashion, and thus should be interpreted to mean “including, but not limited to . . . . ” Also, the term “couple” and derivatives thereof are intended to mean an indirect, direct, optical, and/or wireless electrical connection. Thus, if a first device couples to a second device, that connection may be through a direct electrical connection, through an indirect electrical connection via other devices and connections, through an optical electrical connection, and/or through a wireless electrical connection.
Although method steps may be presented and described herein in a sequential fashion, one or more of the steps shown and described may be omitted, repeated, performed concurrently, and/or performed in a different order than the order shown in the figures and/or described herein. Accordingly, embodiments of the invention should not be considered limited to the specific ordering of steps shown in the figures and/or described herein.
It is therefore contemplated that the appended claims will cover any such modifications of the embodiments as fall within the true scope and spirit of the invention.
The present application claims priority to and incorporates by reference U.S. Provisional Application No. 61/977,407 (attorney docket TI-74512PS) filed Apr. 9, 2014, entitled “Method to Integrate Periodical Structures with Dielectric Waveguides to Control the Dispersion and Frequencies Response of Interconnects using Direct-Write Printing Manufacturing Process.”
| Number | Date | Country | |
|---|---|---|---|
| 61977407 | Apr 2014 | US |
