Transparent Radio Frequency Antennas and EMI Shielding

Abstract

The present disclosure includes and results in the creation of a printed carbon nanotube and / or graphene hybrid antenna and / or EMI shield, consisting of a conductive layer including a metal mesh (MM) layer or nanowire layer on a substrate and a printed signal enhancement layer (SEL) on the conductive layer. The SEL includes an ink including one or both of carbon nanotubes (CNT) and graphene. The circuit pattern results after the "exposed" conductive layer (i.e., areas where the CNT / graphene ink is not printed) is removed by chemical etching or mechanical cutting. The structure (antenna / EMI shield) is preferably, but not necessarily, transparent.

Description

[Technical Field]

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS This application claims priority to U.S. Provisional Patent Application No. 63 / 271,265, filed October 25, 2022. The entire disclosure (text and drawings) of the provisional application is incorporated herein by reference in its entirety for all purposes.

[0002] background The present disclosure relates to radio frequency antennas and electromagnetic interference (EMI) shielding. [Background technology]

[0003] International Publication WO 2016 / 172315 A1 describes a printed carbon nanotube (CNT) hybrid transparent conductive film comprising a silver nanowire (AgNW) layer and a printed CNT ink layer. The entire disclosure of this publication is incorporated herein by reference for all purposes. This publication also describes a "wet wiping" method for removing exposed AgNW regions (i.e., areas not printed with CNT ink).

[0004] International Publication WO2020 / 102392 describes a printed CNT hybrid transparent conductive film that includes a metal mesh (MM) layer used as a simple transparent conductive film and a printed CNT ink layer. The entire disclosure of this publication is incorporated herein by reference for all purposes. A chemical etchant is used to dissolve the exposed areas where the CNTs are not printed, forming a conductive pattern. Summary of the Invention

[0005] The present disclosure is distinguished from the prior art in part by: 1) the synergistic effect of combining CNT and / or graphene with copper (Cu) mesh on the RF properties of transparent circuit structures; 2) RF shielding and transmission / reception benefits by applying CNT and / or graphene ink on top of the mesh; 3) RF shielding and transmission / reception benefits by controlling the dimensions of the Cu mesh; 4) printed carbon nanotube and / or graphene hybrid transparent antennas; and 5) printed carbon nanotube and / or graphene hybrid transparent EMI shielding structures.

[0006] The advantage of using MM is that it can achieve very low sheet resistance (0.2-1 Ω / □) in transparent CNT and / or graphene hybrid film structures while maintaining high transparency (visible light transmittance (VLT) 85%-90%). Low sheet resistance (Rs) is a useful property for antennas and EMI shielding.

[0007] The advantage of using a chemical etchant to dissolve the exposed MM regions is that it is impractical to use simple water / organic solvent wet wiping to remove the MM. However, for chemical etching to work, the printed CNT or graphene ink must also function as an etching mask. This makes the ink a multifunctional material. This ink not only enables the creation of CNT or graphene hybrid (CNT or graphene + MM + polymer binder) transparent conductive films, but also produces films with better conductivity than CNT or MM alone. Furthermore, this ink allows the use of standard flexible printed circuit fabrication methods (i.e., using a chemical etchant to dissolve conductive areas not covered by the etch mask). Etching conditions are described in International Publication No. WO2020 / 102392.

[0008] An alternative to etching is to pattern the film using a "kissing" type automated cutter system.

[0009] In another embodiment, the substrate can incorporate a layer of silver nanowires (AgNWs) that function as the conductive layer in place of the MM described above. The nanowires can be made of other conductive materials (e.g., copper), as further described elsewhere herein.

[0010] In another embodiment, the CNT and / or graphene hybrid film structures can be used as high performance EMI shielding films. [Brief explanation of the drawings]

[0011] [Figure 1] FIG. 1A shows the response (S11, S22, S12, S21) from a test of the microstrip with the SEL, and FIG. 1B shows the response without the SEL. [Figure 2-1] FIG. 2A shows a patch SEL antenna. [Figure 2-2] FIG. 2B shows the antenna response, and FIG. 2C shows the response without the SEL. [Figure 3A] This is a simulation of a copper multi-band tunable antenna tuned to the low frequency band. [Figure 3B] This is a simulation of the antenna with SEL. [Figure 4A] This is a simulation of a copper multiband tuned antenna tuned to the mid-high frequency band. [Figure 4B] This is a simulation of an antenna using SEL. [Figure 5A] This is a simulation of a copper multiband tuned antenna tuned to high frequency bands. [Figure 5B] This is a simulation of an antenna with a SEL. [Figure 6] FIG. 6A shows the simulated and measured results of the S21 and S11 parameters of the copper antenna, and FIG. 6B shows the parameters of the antenna with a SEL. [Figure 7-1] FIG. 7A shows the simulated and measured return loss results for the patch antenna. [Figure 7-2] FIG. 7B shows the efficiency and FIG. 7C shows the gain. [Figure 8] 8A to 8C are diagrams showing radiation patterns of the antennas shown in FIGS. 7A to 7C. [Figure 9-1] FIG. 9A shows the return loss results of the patch antenna simulation and actual measurements. [Figure 9-2] FIG. 9B shows the efficiency and FIG. 9C shows the gain. [Figure 10] 10A to 10C are diagrams showing radiation patterns of the antennas shown in FIGS. 9A to 9C. [Figure 11] The VLT and sheet resistance values ​​of the two antenna simulations are shown. [Figure 12] FIG. 12A is a polar diagram for the copper antenna and the SEL antenna, and FIG. 12B shows the gain of both antennas. [Figure 13A] 1 shows the return loss of a low frequency tuned SEL antenna. [Figure 13B] 1 shows the return loss of a radio frequency tuned SEL antenna. [Figure 14A] The shielding effect of the SEL base shield is shown. [Figure 14B] The shielding effect of another SEL-based shield is shown. [Figure 14C] The shielding effect of another SEL-based shield is shown. [Figure 15] 1 shows the EMI shielding effectiveness of SEL-based shields with different sheet resistance levels. [Figure 16] The shielding effectiveness of two SEL-based shields is compared with state-of-the-art shields. DETAILED DESCRIPTION OF THE INVENTION

[0012] The system, method, and apparatus embodiments described herein are not limited in application to the details of construction and the arrangements of components set forth in the following description or illustrated in the accompanying drawings. The systems, methods, and apparatus may be implemented in other embodiments and may be implemented in various ways. The specific embodiments are provided herein for purposes of illustration only and are not intended to be limiting. In particular, functions, components, elements, and features discussed in connection with any one or more embodiments are not intended to exclude a similar role in other embodiments.

[0013] The embodiments disclosed herein may be combined with other embodiments in any manner consistent with at least one of the principles disclosed herein, and references to "embodiments," "some embodiments," "alternative embodiments," "various embodiments," "one embodiment," etc. are not necessarily mutually exclusive and are intended to indicate that a particular feature, structure, or characteristic described may be included in at least one embodiment. Appearances of such terms herein do not necessarily all refer to the same embodiment.

[0014] Additionally, the phraseology and terminology used herein are for purposes of description and should not be considered limiting. Any reference herein to examples, components, elements, acts, or functions of computer program products, systems, and methods in the singular can also encompass embodiments that include the plural, and any reference herein to any example, component, element, act, or function in the plural can also encompass examples that include only the singular. Thus, singular or plural references are not intended to limit the presently disclosed systems or methods, their components, acts, or elements. The use herein of "including," "comprising," "having," "containing," "involving," and variations thereof, is intended to encompass the items listed thereafter and equivalents thereof, as well as additional items. References to "or" may be construed as inclusive, such that terms described with "or" can refer to a single term, multiple terms, and all of the described terms.

[0015] The impact of signal enhancement layers on RF antenna performance One aspect of this disclosure is the significant impact on antenna response in the 5G frequency range (approximately 3.2-3.8 GHz). Shown below are test results with (Figure 1A) and without (Figure 1B) a signal enhancement layer (SEL) printed on top of the MM layer. Tests were performed using both microstrip evaluation (used for material characterization) and antenna evaluation over a wide frequency range.

[0016] Figure 1B displays the microstrip results and the S11 and S22 response parameters, showing poor antenna performance at high frequencies, as indicated by the dashed ellipse area at high frequencies where there is a lack of dB return loss (reflection) reduction and the reflected power increases significantly. A good target response of: · If S11 and S22 are low → energy is transmitted or dissipated as heat loss. · If S12 and S21 are high → signal transmission and reception is high.

[0017] Additional testing was performed using a "patch" antenna, as shown in Figure 2A. This antenna consists of five substrates, with AgeNT-G3 SEL layers on top of substrate 1, at the interfaces between substrates 2 and 3, and on the bottom of substrate 5. An optically clear adhesive (OCA) was used to form the stack. Figure 2B shows the response of this patch antenna with AgeNT-G3 (defined elsewhere herein), which exhibits substantial response in the 5G bands. Figure 2C shows the antenna response without the SEL, which exhibits almost no response in the same bands (the bands indicated by the areas within the ellipses in both figures). AgeNT is defined in patent publications incorporated herein by reference. At its most basic, AgeNT consists of a MM or nanowire conducting layer formed on a substrate, overlaid with a printing ink containing CNTs and / or graphene and, optionally, a binder.

[0018] Embodiments: Substrate: PET (polyethylene terephthalate), COP (cycloolefin polymer), CPI (transparent polyimide), PC (polycarbonate) Construction MM Materials Cu, Ag, Al, Sn and other metals that may meet performance needs MM pitch: 50, 100, 200, 250, 300, 400, 500 microns Line width: 3, 5, 7, 10, 15, 20 microns Line height: 0.25, 0.5, 0.75, 1, 2, 3 microns Line Patterns Square, Hexagon, Random, Fractal MM structure layer: Substrate / primer layer / blackening / metal mesh / signal enhancement layer / and optional top coat (preferably not required) AgNW material: Diameter 15~35nm Length: 20-50 microns AgNW coverage 15mg / m 2 ~150mg / m 2 , preferably up to 100 mg / m 2 Nanowire structure layer: Substrate / primer layer / AgNW / signal enhancement layer / optional top coat (preferably not required) Signal Enhancement Layer (SEL): Carbon nanotubes (CNT); CNT and graphene; graphene with or without binder, Concentration of conductive components (CNT and / or graphene): 0.05, 0.1, 0.2, 0.3, 0.4, 0.5 grams per liter of each component, or blend or combination Surface coverage of SEL conductive component: 3mg / m 2 , or 0.75, 1.5, 2.25, or 3 mg / m 2 , preferably 3 mg / m 2 , 5 mg / m 2 SEL composition w / binder:binder / conductive component ratio 1 / 1, 20 / 1, 100 / 1, 200 / 1, 240 / 1, 300 / 1, 400 / 1 Definitions of various MM embodiments MM-G1 Hexagonal pattern line spacing (pitch) 500 microns, line width 30 microns, line height 0.5 to 1.5 microns MM-G2 square pattern line pitch 300 microns, line width 5 microns, line height 2 microns MM-G3 square pattern line pitch 100 microns, line width 5 microns, line height 2 microns

[0019] Performance results and examples Materials characterization: Microstrip testing Since none of the layers in the hybrid structure are bulk materials, the electromagnetic permittivity of the substrate is required to model and simulate the antenna: Dielectric constant (ε r ): Related to the operating frequency. · Dissipation factor (TanD): represents the loss of the substrate, which is the main cause of radiation efficiency loss.

[0020] Materials do not have constant properties over frequency, so full RF characterization is necessary. A dielectric probe sensor can be used to measure complex (real and imaginary) permittivity. Initially, antenna substrates were used to perform limited material characterization at the desired frequencies. The Keysight 85070E Dielectric Probe Kit, used with a Keysight network analyzer, determines the inherent electromagnetic properties of many dielectric materials. These properties are determined by their molecular structure. This setup tests dielectric materials from 200 MHz to 50 GHz, providing critical information about materials used in cutting-edge RF and microwave electronic components.

[0021] Preliminary Simulation - Demonstration of Feasibility: Using the initial measured permittivity and loss tangent parameters, we added tuning parameters for the multi-band tunable antenna and performed simulation comparisons across various frequency bands to compare the MM-G2 material set and copper-based designs. As shown in Figure 3A compared to Figure 3B, Figure 4A compared to Figure 4B, and Figure 5A compared to Figure 5C, the MM-G2 exhibited good response across three different frequency ranges (low, mid-high, and high), comparable to the antennas using solid copper for the conductive layer shown in Figures 3A, 4A, and 5A.

[0022] Microstrip material characterization Completion of the initial simulations allowed for subsequent measurements using a prototype consisting of a complete microstrip test circuit capable of measuring the conductivity of the material.

[0023] A network vector analyzer was used to determine the characteristics of the designed microstrip line and compare them with simulations. S-parameter measurements at specific frequencies allowed the skin effect and anomalies due to the sandwich stack to be evaluated. Impedance measurements also allowed the determination of conductivity values ​​to be used in the EM simulation model at these frequencies.

[0024] Comparison of simulation results (microstrip test structures) and measurements allows the design of antennas with predictable performance.

[0025] The pitch of the metal mesh lines affects the ability to simulate expected antenna performance. Using the results of microstrip tests as a material characterization tool, as described above, the antenna response can be defined at various frequencies based on the S11, S22, S12, and S21 parameters.

[0026] S-parameters define the reflected wave at a particular port as the incident wave at each port.

[0027] The goal is to have low S11 and S22 → energy is either transmitted (wanted) or dissipated as heat loss. For example, if S21=0 → all power from port 1 reaches port 2; if S21=-10DB → only 10% reaches port 2.

[0028] MM-G2 Microstrip Simulation Results: For the MM-G2 geometry (line pitch 300um), the antenna simulation did not have a closed-loop solution. There were physical limitations to parameter optimization and impedance optimization, which prevented satisfactory tuning. Since the two curves (S21 and S11) are interdependent, it was not always possible to obtain a good correlation between the simulation and measurements, even with known physical entities (substrate thickness, dielectric constant, track width) in place.

[0029] MM-G3 microstrip simulation results: For the MM-G3 geometry (100 μm line pitch), antenna simulations yielded a closed-loop solution, as shown in Figures 6A and 6B. Sheet resistance and reactance were defined as frequency-dependent functions (bulk metal does not require this), and the correlation between simulated and measured S-parameters was very good.

[0030] Antenna simulation and measurement results: The evaluation was performed using a patch antenna design similar to that shown in Figure 2A. The evaluation was performed by varying the pitch (i.e., spacing) of the metal mesh lines to show the effect of geometry on the measured antenna performance (return loss (reflectivity), gain, efficiency, and radiation pattern).

[0031] G3 patch antenna prototype test: Figures 7A-7C and 8A-8C show the simulated and measured return loss results, antenna efficiency, antenna gain, and radiation pattern for the patch antenna. For the "MM-G3" design (100 micron line pitch in a square pattern), the antenna efficiency, antenna gain, and radiation pattern correlate very well, as shown in Figures 8A-8C. Figures 8A-8C also show a very good correlation between the measured and simulated S11 values. The fabricated antenna exhibited a slightly wider bandwidth than the simulation.

[0032] G3 Efficiency and Peak Gain Comparison The efficiency (Figure 7B) and peak gain (Figure 7C) confirm the wide bandwidth without compromising absolute efficiency values ​​across the entire bandwidth. The desired peak gain is slightly below threshold only at the lower end of the band (<3220 MHz).

[0033] G2 patch antenna prototype test: 9A-9C and 10A-10C show the simulated and measured return loss results, antenna efficiency and gain, and radiation pattern of the patch antenna "MM-G2" design with a square pattern and a line pitch of 300 microns.

[0034] G2 Patch Antenna Prototype Test - Return Loss Comparison The correlation between the measured and simulated S11 values ​​is low (vs. G3). The fabricated antenna exhibits a much wider bandwidth than the simulation (approximately 50%). See Figure 9A.

[0035] G2 Efficiency and Peak Gain Comparison The efficiency (Figure 9B) and peak gain (Figure 9C) confirmed the wider bandwidth without compromising the absolute efficiency values ​​across the entire bandwidth. The measured efficiency was also higher than predicted. The G2 material was expected not to meet the desired minimum peak gain across the entire bandwidth (due to its high resistivity). However, due to its high efficiency, the peak gain was higher than simulated. Both the return loss results and the efficiency impact are relevant to the microstrip test design. The microstrip conductor lines were primarily smaller than the design rule used here (no feature should have physical dimensions greater than 10 times the mm pitch). The patch antenna met this design rule, resulting in a favorable result relative to predictions.

[0036] G2 radiation pattern The electric field is less uniform compared to the results obtained with the G3 material, see Figures 10A, 10B, and 10C.

[0037] It is noteworthy that the performance for the larger line spacing (300 micron pitch) is reasonable, but not as good as for the smaller line spacing (100 micron pitch).

[0038] The major difference between the G2 microstrip results and the patch antenna results is that microstrip does not incorporate a specific design rule that the feature size of the MM conductor must be at least 10 times the MM pitch. For example, in a G2 mesh pattern, the conductor line width must be at least 3 mm. For example, for a G1 mesh pattern, the conductor line should have a width of at least 1 mm.

[0039] The effect of metal mesh geometry on VLT and sheet resistance: The width of the metal mesh lines affects the visibility (VLT) of the antenna and therefore the definition of a "transparent antenna." See Figure 11.

[0040] Further material observations: The width of the metal mesh lines affects the sheet resistance of the conductor. The pitch of the metal mesh wires affects the sheet resistance (electrical properties of the conductor). · Metal mesh can be used as an antenna conductor, ground plane, or tuning layer.

[0041] The use of metal mesh provides performance comparable to bulk metal antenna designs. Figures 12A and 12B show monopole transparent Bluetooth antennas made with copper and with a CNTSEL layer. The radiation patterns of both are essentially the same (Figure 12A). The upper gain curve (higher gain) is for the SEL antenna.

[0042] Multiband Antenna Design : By incorporating capacitors into the circuit, metal mesh antennas can be tuned to specific frequencies or made multi-band compatible, and this process has demonstrated that SEL antennas can be tuned to specific frequencies over a wide range.

[0043] For example, Figure 13A shows tuning in low frequency band group A [570-750 MHz], and Figure 13B shows tuning in high frequency band group B [1300-3800 MHz].

[0044] Antenna manufacturing example 1Ω / □MM version: 1. A transparent conductive film (TCF) was fabricated on a PET (100 μm) substrate. A copper metal mesh (MM) was deposited on the substrate in a square pattern with a 300 μm pitch, 5 μm width, and 2 μm height. This MM structure was named MM-G2. The copper MM film was screen-printed with carbon nanotube ink (VC201 single-wall CNT ink, manufactured by Chasm Advanced Materials Inc.) using a 305 polyester mesh screen (30 μm wet film thickness) with a 2.5-inch block pattern. The ink was formulated to a CNT concentration of 0.1 g / L and contained a binder (polymer binder; modified methacrylic copolymer) at a binder:CNT ratio of 240:1. The printed CNT layer was dried in a tunnel dryer at 100 °C with a dwell time of 3–4 min. The sample was then cooled to ambient temperature (25 °C).

[0045] The film was treated in an autoetcher containing 10% FeNO3 solution, followed by a DI water rinse and drying.

[0046] The CNT ink was etched after screen printing with a 240:1 binder: After screen printing and etching of the CNT ink, in the 2.5" CNT pattern area, %VLT and Rs remained at 90.6% (minus the substrate) and <1 / , respectively. In the exposed area outside the 2.5" CNT pattern area, %VLT and Rs increased to 99.6% (minus the substrate) and infinity, respectively.

[0047] 2. A TCF was fabricated using PC (175 μm) substrates with a uniform silver nanowire coating on the substrate. The AgNW film was screen-printed with carbon nanotube ink (VC200 single-wall CNT / graphene ink from Chasm Advanced Materials Inc.) using a 305 polyester mesh screen with a 2.5-inch block pattern (~30 μm wet film thickness). The ink was formulated to have CNT and graphene concentrations of 0.05 / 0.05 g / L, respectively, and contained a binder (polymer binder; modified methacrylic copolymer) at a binder:CNT ratio of 120:1. The printed CNT layer was dried in a tunnel dryer at 100 °C with a residence time of 3–4 min. The sample was then cooled to ambient temperature (25 °C).

[0048] The film was treated in an autoetcher containing 10% FeNO3 solution, followed by a DI water rinse and drying.

[0049] After screen printing the 120:1 binder, the CNT ink was etched. After screen printing and etching the CNT ink, the %VLT and Rs remained at ~92% (minus the substrate) and 10 / □, respectively, in the patterned area. In the exposed area outside the CNT patterned area, all excess AgNWs were etched away.

[0050] The polymer binder enhances the environmental stability and adhesion of the printed CNT hybrid circuit. It also protects the MM from chemical etching (i.e., it is a component that provides an etch mask function). The binder should have good environmental stability and adhesion properties, low haze, and high transparency.

[0051] It is reasonable to expect that many different binders will be used. Selection criteria for suitable polymer binder candidates include: Good optical properties (high transparency, low haze, low color, refractive index similar to PET) Good adhesion to commonly used plastic film substrates (PET, PC, acrylic, etc.) -Temperature processing requirements (below 120°C) compatible with plastic film substrates · Solubility compatible with ink formulations (e.g. good solubility in alcohol and / or amine components). Chemical resistance to common etching solutions used for Cu.

[0052] The CNT type used in the examples is single-walled CNT, however, it is reasonable to expect that good results would be obtained if double-walled, few-walled, or multi-walled CNTs were used instead.

[0053] EMI shielding example Samples of AgeNT film were tested for EMI shielding effectiveness. Shielding effectiveness (SE) is typically measured as the magnitude of the incident electric field, E i and the magnitude of the transmitted electric field E t It is defined as the ratio of: JPEG2024545565000002.jpg13159

[0054] The higher the dB value, the greater the signal attenuation. Attenuation is frequency dependent and highly dependent on the aperture in the shielding material. For transparent shields, there is a trade-off between attenuation and total visible light transmittance. Attenuation results are shown in the examples below.

[0055] EMI Shielding Example 1: Both metal mesh and silver nanowire AgeNT structures were tested. The results in Example 1 were performed using a sample with ground contacts on two of the four sides of the sample. Despite not being completely surrounded by ground contacts, the SE was significant. Detailed descriptions and results are provided below.

[0056] Test method for "Test 2.1.2" Testing was performed in a shielded enclosure manufactured by Sprague Shielding Corporation. Attenuation testing demonstrated that the shielded enclosure met the attenuation requirements of IEEE-STD-299.

[0057] The AC power available within the shielded enclosure is 110V AC, 220V AC, single-phase and three-phase, 60 cycles. The power line filter is rated at 100dB attenuation from 10kHz to 10GHz.

[0058] Support equipment such as the signal generator and computer system were installed outside the shielded enclosure. The detection system was installed inside the shielded enclosure. Matched transmit and receive antennas were installed on either side of a common wall where the material under test was mounted.

[0059] A 16" x 16" adapter plate with a 6.25" x 3.5" opening in the center was attached to the chamber wall. Two rows of copper fingers were used along the perimeter of the adapter plate-wall interface.

[0060] The transmitting and receiving antennas were placed 0.75 meters away from either side of the aperture, and then an open reference measurement was taken and recorded from the aperture.

[0061] After the open reference measurement, the protective backing of the AgeNTG2-1 sample was peeled off, exposing the coated surface. This surface was placed on the aperture and secured in a metal frame with six screws. The measurement was repeated at the same frequency and signal generator level as the open reference and recorded on the data sheet. SE = Oper. Reference Level (dB) - Level with Sample Mounted (dB). This process was repeated for the remaining two samples. See Figures 14A and 14B (MM, 1 Ω / ), and Figure 14C (AgNW, 10 Ω / ).

[0062] E-field tests were performed at the following frequencies: 100 MHz, 200 MHz, 400 MHz, 600 MHz, 800 MHz, 1 GHz, 2 GHz, 6 GHz, 8 GHz, 10 GHz, 12 GHz, 14 GHz, 16 GHz, 18 GHz, 20 GHz, 22 GHz, 24 GHz, 26 GHz, 28 GHz, and 30 GHz.

[0063] EMI Shielding Example 2 There is a need for transparent EMI shielding films that provide high EMI shielding effectiveness over a wide frequency range (1 MHz to 40 GHz). This is particularly important in defense and avionics applications, as well as security glass applications. An example of the required performance is shown in Figure 15, which indicates that the lower the sheet resistance, the higher the shielding effectiveness. Tests were conducted to compare current products with AgeNT.

[0064] AgeNT EMI shielding film achieves this high shielding performance while maintaining high transparency. Figure 16 shows data showing that AgeNT-1-G3 and AgeNT-G1 meet the stringent specification of 40 dB attenuation (horizontal dashed line). This means that over 99.99% of the power is attenuated and the visible light transmittance is over 76% (including s-glass).

[0065] A comparison of the current best products with AgeNT-G1 and AgeNT-G3 is shown in Figure 16 and shows superior, or at least comparable, SE over a wide frequency range up to approximately 10 GHz and beyond.

[0066] While several aspects of at least one embodiment have been described above, it will be appreciated that various alterations, modifications, and improvements will readily occur to those skilled in the art. Such alterations, modifications, and improvements are intended to be part of this disclosure and to be within the scope of the invention. Accordingly, the foregoing description and drawings are by way of example only, and the scope of the invention should be determined from proper interpretation of the appended claims and equivalents thereof.

Claims

1. 1. A printed carbon nanotube hybrid antenna, comprising: A substrate; a conductive layer on a surface of the substrate, the conductive layer comprising a metal mesh (MM) layer or a nanowire layer; a printed signal enhancement layer over the conductive layer, the signal enhancement layer comprising a carbon nanotube (CNT)-containing ink layer and / or a graphene ink layer; An antenna characterized in that a circuit pattern is produced after the exposed conductive layer on which no ink is printed is removed.

2. 2. The antenna of claim 1, having a visible light transmission (VLT) (without substrate) of at least about 90%.

3. 2. The antenna of claim 1, comprising at least one or more of the following materials and variables: Substrate PET, COP, CPI, PC Construction MM Material Cu, Ag, Al, Sn, or other suitable conductive metal MM pitch: 50, 100, 200, 250, 300, 400, 500 microns Line width: 3, 5, 7, 10, 15, 20 microns Line height 0.25, 0.5, 0.75, 1, 2, 3 microns Line Patterns Square, Hexagon, Random, Fractal Structural layer: Substrate / primer layer / blackening / metal mesh / signal enhancement layer / optional top coat (preferably not required) AgNW material: Diameter 15-35nm Length: 20-50 microns AgNW coverage: 15 mg / m ２ ~150mg / m ２ , preferably up to 100 mg / m ２ Structural layer: Substrate / Primer layer / AgNW / Signal enhancement layer / Optional top coat (preferably not required) Signal Enhancement Layer (SEL): Carbon Nanotubes (CNT); CNT and graphene; graphene with or without binder, Concentration of conductive components (CNT and / or graphene): 0.05, 0.1, 0.2, 0.3, 0.4, 0.5 grams per liter of each component, or blend or combination Surface coverage of SEL conductive component: 3 mg / m ２ , or 0.75, 1.5, 2.25, 3 mg / m ２ , preferably 3 mg / m ２ , 5 mg / m ２ SEL compositions with binder: binder / conductive component ratio 1 / 1, 20 / 1, 100 / 1, 200 / 1, 240 / 1, 300 / 1, 400 / 1 Definitions of various MM embodiments MM-G1 Hexagonal pattern line spacing (pitch) 500 microns, line width 30 microns, line height 0.5 to 1.5 microns MM-G2 Square pattern line pitch 300 microns, line width 5 microns, line height 2 microns MM-G3 Square pattern line pitch 100 microns, line width 5 microns, line height 2 microns.

4. 1. An EMI shield comprising: A substrate; a conductive layer on the substrate, the conductive layer comprising a metal mesh (MM) layer or a nanowire layer; a printed signal enhancement layer over the conductive layer, the signal enhancement layer comprising a carbon nanotube (CNT) and / or graphene ink layer; An EMI shield characterized in that a circuit pattern is produced after the exposed conductive layer on which no ink is printed is removed.

5. 5. The EMI shield of claim 4 having a visible light transmission (VLT) (without substrate) of at least about 90%.

6. 5. The EMI shield of claim 4, comprising at least one or more of the following materials and variables: Substrate PET, COP, CPI, PC Construction MM Material Cu, Ag, Al, Sn, or other suitable conductive metal MM pitch: 50, 100, 200, 250, 300, 400, 500 microns Line width: 3, 5, 7, 10, 15, 20 microns Line height 0.25, 0.5, 0.75, 1, 2, 3 microns Line Patterns Square, Hexagon, Random, Fractal Structural layer: Substrate / primer layer / blackening / metal mesh / signal enhancement layer / optional top coat (preferably not required) AgNW material: Diameter 15-35nm Length: 20-50 microns AgNW coverage: 15 mg / m ２ ~150mg / m ２ , preferably up to 100 mg / m ２ Structural layer: Substrate / Primer layer / AgNW / Signal enhancement layer / Optional top coat (preferably not required) Signal Enhancement Layer (SEL): Carbon Nanotubes (CNT); CNT and graphene; graphene with or without binder, Concentration of conductive components (CNT and / or graphene): 0.05, 0.1, 0.2, 0.3, 0.4, 0.5 grams per liter of each component, or blend or combination Surface coverage of SEL conductive component: 3 mg / m ２ , or 0.75, 1.5, 2.25, 3 mg / m ２ , preferably 3 mg / m ２ , 5 mg / m ２ SEL compositions with binder: binder / conductive component ratio 1 / 1, 20 / 1, 100 / 1, 200 / 1, 240 / 1, 300 / 1, 400 / 1 Definitions of various MM embodiments MM-G1 Hexagonal pattern line spacing (pitch) 500 microns, line width 30 microns, line height 0.5 to 1.5 microns MM-G2 Square pattern line pitch 300 microns, line width 5 microns, line height 2 microns MM-G3 Square pattern line pitch 100 microns, line width 5 microns, line height 2 microns.

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