WO2022133773A1

WO2022133773A1 - The anti-reflection structure and the user's equipment comprising the same

Info

Publication number: WO2022133773A1
Application number: PCT/CN2020/138517
Authority: WO
Inventors: Weigang LIN; Min Ding; Jeffrey M Florczak; Jie Huang; Derek Jason Dehn; Jiaru XU; Kun Wang; Wei Li; Dipankar Ghosh
Original assignee: 3M Innovative Properties Company
Priority date: 2020-12-23
Filing date: 2020-12-23
Publication date: 2022-06-30

Abstract

The present disclosure relates to the anti-reflection structure for millimeter wave application and the user's equipment comprising the same. The anti-reflection structure of the present disclosure includes the comprises at least one antireflection film with a specific thickness, permittivity (Dk), a permeability (Uk) of 1 to 2, and a dissipation factor (Df) of 0 to 0.1. According to the anti-reflection structure, it has advantageous transmittance and reflectance in a bandwidth with a frequency of 20-45 GHz

Description

THE ANTI-REFLECTION STRUCTURE AND THE USER’S EQUIPMENT COMPRISING THE SAME

TECHNICAL FIELD

The present disclosure relates to a structure applied in the field of communications. In particular, the present disclosure relates to an anti-reflection structure for millimeter wave applications and a user’s equipment comprising the same.

BACKGROUND

The 5th generation, or 5G, communication standard is an evolutionary change in wireless communication technologies with the goal of improving data transfer speeds, latency, reliability, and enabling denser wireless communication coverage. The 5G standard adds additional spectrum to achieve wider bandwidths, proposing spectrum allocations near 3.5 GHz and multiple bands in the 24-40 GHz range (24-60 GHz) . The wavelengths in the 24-40 GHz (24-60 GHz) range are often referred to as mm-wave, and due to the large available bandwidths, these frequencies are often referred to as ultra-wide band (UWB) . Two frequency ranges, 24.25-29.5 GHz and 37-40 GHz are often used in 5G UWB for mobile device communication.

In recent years, the technology of 5G communications and the related equipment, such as 5G smartphones, have been attracting widespread attentions. In modern smartphone manufacturing, plastic, glass and ceramic are the three main materials used for back-cover. Among them, the glass and ceramic are very attractive for high level smart phones because of their shinny appearances. However, as the mm-wave of 5G bandwidth is used to wireless communication, signal reflections on the back-cover should be seriously considered. Especially for glass and ceramic material with high permittivity, the signal loss due to reflection can rise up to 30%to 50%, and even to a higher degree (See Fig. 1) . It is known that the reflection losses can be mitigated by anti-reflection coatings and there are well known designs to address antireflection. For example, when a cover of equipment is made of zirconia ceramic, the antireflection can be achieved by adopting another ZrO ₂ with the same thickness as the wave path-difference of reflection to half wavelength. It leads to the counteraction of the wave and reduces a lot of reflection with highly increasing the transmission. However, in the mass production of practical applications, it is very difficult to add a coating of same material as the back cover of the user’s equipment because the materials of back covers may vary for different applications, and the back covers are always not simple structure (s) , which make it impossible to have the antireflection consisting of the same materials as the cover.

Some studies have been conducted on the Anti-Reflection structures. For instance, the US patent publication US3,780,374 (Shibano, et. al) provides two matching layers on either side of a radome having effective dielectric constant equal to the radome’s dielectric constant. However, both surfaces of the dielectric plate are provided with the same or a different material and the surfaces are given a lattice-like or embossed construction so as to construct the average dielectric constant of the matching layers. The design of the patent publication uses some structured materials to achieve the average dielectric constant, which makes the process complex and lack of industrial applicability. Also, in the smart phone applications, the space between the back cover and the antenna is quite small such that it is not quite advantageous to make an embossed construction structures in a narrow space.

Therefore, it is highly needed to provide a solution to obviously reduce the net reflected energy for any particular polarization and angle of incidence for a given range of wavelength, especially a solution for the anti-reflection structure for 5G bandwidth, which is of advantageous anti-reflection across the 5G bandwidth and is applicable to mass production in practice.

SUMMARY OF THE INVENTION

To solve one or more problems indicated above, the present disclosure provides an anti-reflection structure, which is specially applied for the glass (Dk 5～7) and ceramic (Dk>20) materials of cover whose transmission loss of 5G signal can be relative high, especially for the ceramic which can lose up to 70%or more of 5G signal. The film design can involve multilayers and composite materials and does not require a change to the thickness of the original enclosure material. The film's permittivity, permeability along with the thickness can be selected to provide the lowest transmission loss in small air gap between antenna and back cover across the entire mm-wave bands allocated for 5G (e.g. 24 GHz to 40 GHz) .

In one or more embodiments, the present disclosures provides an anti-reflection structure, which comprises at least one antireflection film with a thickness of 0.1 mm to 2 mm, preferably 0.4 to 1.2mm, wherein the antireflection film has a permittivity (Dk) of 1.3 to 40, a permeability (Uk) of 1 to 2, and a dissipation factor (Df) of 0 to 0.1, in a bandwidth with a frequency of 20-45 GHz.

In another aspect, the present disclosures provides a polymer-based antireflection film, the polymer-based antireflection film comprises a polymer body and 50 wt.%to 98 wt. %, preferably 70 wt. %to 96 wt. %of oxide ceramic filler, based on the total weight of the polymer-based antireflection film, wherein the oxide ceramic filler is selected from one or more from the group of magneto-plumbite type magnetic ceramic, spinel type magnetic ceramic, and garnet-type magnetic ceramics.

In the embodiments of the polymer-based antireflection film, the material of polymer may be any of the thermoplastic and crosslinked polymeric materials. And the polymer (s) can be selected from a group comprising polyolefin (e.g., Polyethylene, polypropylene) , fluorinated alkene (e.g., Vinylidene Fluoride, Perfluoro alkylene) polyamides, polyimides, phenolic resins, polystyrene, styrene-acrylonitrile copolymers, epoxies, and the like. In alternative or preferable examples, the thermal plastic polymer may comprise thermal plastic elastomer (TPE) , polyethylene (PE) , polypropylene (PP) , Rubber and thermal plastic urethane (TPU) .

In further another aspect, the present disclosures provide a user equipment, which comprises the polymer-based anti-Reflection film according to any one of the embodiments indicated above.

It is noted that in each of these embodiments, the anti-reflection structures, the AR films and the equipment may have anyone or any combination of various attributes as described herein.

BRIEF DESCRIPTION OF DRAWINGS

The drawings described herein are only for illustrative purposes of the described embodiments, rather than showing all possible implementations, and are not intended to limit the scope of the present disclosure. In the drawings:

Figure 1 shows the reflection of a radome or back cover for millimeter wave application. 1ē2 and 3 are reflected waves, 4 is transmitted wave, ‘a’ is radome or backcover, sometimes includes decoration film.

Figure 2 shows the reflection of a radome or back cover with an anti-reflection film for millimeter wave application. In Figure 2, ‘b’ is anti-reflection film.

Figure 3 shows the transparency (S21) and reflectance (S22) measurement of the present disclosure (Ex. 2 in table 2 with the Silicone + BaFe ₁₂O ₁₉ ceramic filler) .

Figure 4 shows the variation trends of the transparency and reflectance VS. the thickness of the AR film (Silicone + BaFe ₁₂O ₁₉) .

Figure 5 shows the embodiments of different loading ratio and different filler compositions for the AR structures ( (with LDPE (low density polyethylene) + BaFe ₁₂O ₁₉, SEBS (Styrene Ethylene Butylene Styrene) + BaFe ₁₂O ₁₉/SrBe ₁₂O ₁₉) .

Figure 6 shows the transmittance of the composite AR film with different thickness, wherein the AR film consists of SEBS + SrTiO ₃ + SrFe ₁₂O ₁₉ (4: 3) and the filler takes 87.5%weight percentage of the whole AR film.

Figure 7 shows a back cover of a user’s equipment with the antenna array having a gap therebetween. In figure 7, ’ c’ is antenna array, ‘d’ is air gap.

Figure 8 shows the simulated CDF (Cumulative Distribution Function) graph with the SEBS and BaFe ₁₂O ₁₉ with an air gap 0.02mm between the cover inner surface and the antenna surface.

Figure 9 shows the simulation structures with the SEBS and BaFe ₁₂O ₁₉ with an air gap 0.02mm between the cover inner surface and the antenna surface. In figure 9ē ’a’ is radome and/or backcover, ‘b’ is anti-reflection film, ‘c’ is antenna array, ‘d’ is air gap and e is printed circuit board.

Figure 10 shows the tested CDF graph with the SEBS and BaFe ₁₂O ₁₉ with an air gap 0.02mm between the cover inner surface and the antenna surface.

DETAILED DESCRIPTION AND EMBODIMENTS

Examples of the present disclosure will be described more fully with reference to the drawings. The following description is merely exemplary, and is not intended to limit the present disclosure, or application and use thereof.

Example embodiments are provided so that the present disclosure is thorough and fully convey its scope to those skilled in the art. Various specific details such as examples of specific compositions, elements, and methods are described to provide a detailed understanding of the embodiments of the present disclosure. It would be apparent to those skilled in the art that the exemplary embodiments may be implemented in many different forms without specific details, which should not be construed as limiting the scope of the present disclosure. In some example embodiments, well-known processes, well-known structures, and well-known technologies are not described in detail.

Raw Materials and the Testing method for the AR film

The raw materials adopted in the present disclosure may be available through commercial access. Or they may be synthesized by inventors of the present disclosure. The raw materials used in the examples and comparative examples according to the present invention are as shown in Table 1 below. Unless otherwise indicated, the raw materials were used directly without additional purification.

The skilled man would know well how to obtain the raw materials for AR structures in light of the teaching of the present disclosures. Information of some raw materials or precursors is listed in the following table.

TABLE 1: The sources of some Raw materials

Regarding the testing method for the embodiments, the “Two port T/R method” was used to represent the effects (e.g., transmittance and/or reflectance) of the AR structures. And TE ₁₀ mode is also supported for permittivity measurement. In some embodiments, S ₁₁, S ₁₂, S ₂₁, S ₂₂ VS. Frequencies were measured to illustrate the testing result. S ₁₁ and S ₂₂ stand for the properties of reflectance of a structure, while S ₁₂ or S ₂₁ represents the transmittance of an AR structure of polymer film. It is also well known the relationship between the value of “dB” and properties of transmittance or reflectance. Taking the transmittance of a structure as an example, the tested value of dB can be interpreted to the transmittance (Tr) by the equation of “10Log (Tr) = dB” . For instance, if the transmittance of a structure is 50% (0.5) , then the dB value can be calculated by “10Log (0.5) =-3dB” . In other words, “-3dB” of a measurement may represent “50%” of transmittance of a structure or an AR film. With this calculation relationship, it can be understood that a bigger minus value of a dB value represents a lower degree of reflectance, and a smaller minus value of a dB value represents a higher degree of transmittance.

Detailed formulations of Examples 1 to 26 are listed in Tables 2.

A typical manufacturing method was conducted that the VS 165000 (5 g) and VS 5000 (5 g) was mixed with Pt catalyst (0.25 g) with strong stirring for 1 min, then 1-Ethynyl-1-cyclohexanol (0.08 g) was added, after strong stirring for 1 min, XL 1341 (0.5 g) was added. And the mixture was stirred for 2 mins. Then, the specific fillers (e.g., ceramic particles shown in table 1 and 2 were added and the mixture was strongly mixed for 2 mins and degassed for 2 mins. The mixture then was hot pressed in two liners, and heated at 120 centigrade (℃) for 1.5 h, then the film was peeled off from liner for use. The specific weight ratios and the parameters of the AR films are illustrated in the following Table 2 (Example table) . To prepare example 2, 3, 4, 5, above method could be used.

A typical manufacturing method for a mixed ceramic fillers were conducted that SEBS and fillers (e.g., two composites from SrFe ₁₂O ₁₉, BaFe ₁₂O ₁₉ and TiO ₂) were mixed at 200 centigrade (℃) for 30 mins. Then the hybrid was hot pressed at 210 centigrade (℃) to get specific film (0.1～2mm) . The specific components and the weight ratios of each element are also depicted in the following Table 2 (Example table) . To prepare example 1, 6-10, 12-25, above mentioned method could be used.

A typical manufacturing method for high loading ceramic fillers were conducted as below: powdered ultra-high molecular weight polyethylene (GUR-2126 UHMWPE, Celanese, Irvine, TX, US) was fed at 0.31 pounds per hour using a loss in weight feeder (Coperion KT20, Coperion, Stuttgart, Germany) into the feed funnel of a twin screw extruder (25 mm co-rotating twin screw extruder, Berstorff, Germany) . The extruder temperature profile was zone 1 (feed funnel) at 21℃, zone 2 at 65℃, zone 3 at 109℃, zone 4 at 163℃, zones 5-8 at 177℃ and 250 rpm screw speed. Mineral oil was pumped at 2.3 pounds per hour into the extruder open barrel zone 3 using a gear pump (Zenith Pumps, Monroe, NC, US) and Coriolis mass flow meter (Micromotion mass flow meter, Emerson Electric Co, St. Louis, MO, US) . Strontium ferrite powder (HM418, Hoosier Magnetics, Ogdensburg, NY) was fed at 7.39 pounds per hour from a loss in weight feeder in weight feeder (Coperion KT20, Coperion, Stuttgart, Germany) into a side stuffer (Century Extrusion, Travers City, MI) which was connected to zone 5. The extruder was connected melt pump (4.7-1, Witte Pumps and Technology LLC, Lawrenceville, GA) at 190℃ to a 6 inch (15.24 cm) drop die (Nordson Extrusion Die Industries, Chippewa Falls, WI, US) at 190℃. The hot film coming from the die was quenched on a smooth casting wheel at 60℃. The speed of the casting wheel was set at 0.8 feet per minute (0.24 m/min) . The mineral oil in the films was then extracted with 3M NOVEC 72DE (3M Company, St. Paul, MN, US) by soaking 5 inch x 10 inch (12.7 cm x 25.4 cm) films three times for 10 minutes each time. The NOVEC 72DE was subsequently allowed to evaporate from each sample by hanging the film inside a fume hood. (Example table) To prepare example 11, 26, above method is usable.

In the embodiments of the present disclosure, the antireflection (AR) film or AR structure may be constructed by the parameters of one or more of permittivity (Dk) , permeability (Uk) , the dissipation factor (Df) and the thickness of the AR film. In some embodiments, the AR film has a permittivity (Dk) of 4 to 16, a permeability (Uk) of 1.05 to 1.4, and a dissipation factor (Df) of 0 to 0.07, in a bandwidth with a frequency of 24-40 GHz. And the AR film is polymer-based antireflection film comprises single oxide ceramic fillers or a mixture of plurality of oxide ceramic filler.

Preferably, the oxide ceramic fillers comprising ferrite ceramic. And the ferrite ceramic comprises magneto-plumbite type magnetic ceramic, spinel type magnetic ceramic, and garnet-type magnetic ceramics, such as Me2Fe ₁₂O ₁₉, Me3Fe ₂O _4, Me4 ₃Fe ₅O ₁₂, wherein Me2 is selected from one or more of Ba, Sr, Pb; Me3 is selected from one or more of Mg, Mn, Ni, Fe, Cd, Cu; and Me4 is selected from one or more of Y, Sm, Eu, Dy, Tm. All the suitable oxide ceramic for current disclosure should have permeability higher than 1 at millimeter wave band of 20-45GHz. The suitable oxide ceramic includes one or more from the group of BaFe ₁₂O ₁₉ (available from Beijing Daoking, with a particle size of 1-3um (SEM) ) , SrFe ₁₂O ₁₉ (available from Hoosier Magnetics, HM418) , PbFe ₁₂O ₁₉ , Y ₃Fe ₅O ₁₂, CoFe ₂O _4.

In the mixed ceramics, alternatively the oxide ceramic filler further comprises one or a plurality of items selected from the group consisting of TiO ₂ and Me1TiO ₃, wherein Me1 is selected from one or more of Sr, Ba, Ca.

Regarding the weight ratio of the ceramic filler (s) and the polymer base, the AR film may comprise 50 wt. %to 98 wt. %, preferably 70wt. %to 96 wt. %of oxide ceramic filler based on the total weight of antireflection film. In alternative examples, the polymer base is the thermal plastic polymer, which comprises thermal plastic elastomer (TPE) , polyethylene (PE) , polypropylene (PP) , Rubber and thermal plastic urethane (TPU) .

Regarding the thickness of the structure, the AR film may have a thickness of 0.1 mm to 2.0 mm, preferably 0.02 mm to 1.0 mm. In the embodiments of the present disclosure, the AR structure of AR film may be provided with a substantially flat or smooth structure. And the AR film also can be formed to conform to the surface of the cover or back plate of a user’s equipment. Hereinafter are the main examples conducted in the present disclosure.

Specific formulations for Embodiment 1 to 26 are described in Table 2.

Table 2: Main examples of the AR films

Referring now to Fig. 3, it shows the transparency and reflectance measurement of the present disclosure (Ex. 2 showed in table 2 with the Silicone + BaFe ₁₂O ₁₉ ceramic filler) . It can be shown in (a) of Fig. 3 that the base substrate (including back cover and decoration film) with the AR film of Silicone + BaFe ₁₂O ₁₉ ceramic filler shows a great improvement in the transparency properties (S21) , wherein the AR film achieves improvement on the whole 26-40GHz, and particular a more then 3 dB improvement between the frequency of 32-38GHz. Also, it is clear from (b) of Fig. 3 that the AR film helps eliminate the reflectance between the 26 to 40GHz.

During the experiments of the present disclosure, it was also found that the fillers consist of or comprising one or more ferrite ceramic achieves desired or adventurous gain in the transparency of 5G bandwidth signals.

Now making reference to Fig. 4, wherein it shows the effectiveness or affection of the thickness of the AR film for the transparency and reflectance, In this series of experiments, silicone was the polymer base and BaFe ₁₂O ₁₉ was selected as the ceramic filler and the DK, Uk, Df, were the parameters defining the properties of the films. Moreover, it is noted that the thickness of the AR film is varied from about 0.3 mm to about 1.4 mm, while keeping the three parameters (DK, Uk, Df) constant.

Table 3: The thickness variation of the AR film

No.	Filler	Thickness (mm)	Dk	Uk	Df
27	BaFe ₁₂O ₁₉	0.33	5.5	1.1	0.15
28	BaFe ₁₂O ₁₉	0.69	5.5	1.1	0.15
29	BaFe ₁₂O ₁₉	1.35	5.5	1.1	0.15

From (a) and (b) of Fig. 4, it is shown that the basement without the AR film achieve a low transparency and a high reflectance. When the AR film is disposed on the base, the transparency was improved, and the reflectance was reduced. It was further noted that a higher thickness of the AR film results in low frequency range. That is to say, the gain or improvement moves toward lower frequency range (e.g. 26 GHz to 30GHz) with the AR films become thicker. It can be seen from the series of experiments that the transparency and reflectance may be adjusted via the thickness design of the film together with the parameters of DK, Uk and Df.

Next moving to the embodiments shown in Fig. 5, it is shown the embodiments of different loading ratio and different filler compositions for the AR structures. According to (a) of Fig. 5 it is shown that the transparency of the AR film (with LDPE+ xBaFe ₁₂O ₁₉) increases with the loading ratio of BaFe ₁₂O ₁₉ increased from 60%to 90%wt. In this series of embodiments, the best examples may have 0.61 dB and 3.51 dB transmission improvement at 28 and 39 GHz, respectively. The formulation is to use 15 wt. %LDPE or SEBS as thermoplastic polymer matrix and 85 wt. %BaFe ₁₂O ₁₉ as the filler (the top line in (a) of Fig. 5) . Also, from (b) of Fig. 5, it is shown that 85 wt. %BaFe ₁₂O ₁₉ loading percentage is a more advantageous practice, which provide significant improvement in signal transmission.

Therefore, according to the present disclosure, preferably, the fillers (one filler or more than one fillers together) may possess 70wt. %to 98 wt. %, or 70wt. %to 96 wt. %, or 80wt. %to 95 wt. %, or 85wt. %to 95 wt. %of the whole AR film, in order to achieve an even higher transparency for the AF film.

In some embodiments of the present disclosure, the particle size of oxide ceramic fillers (the oxide ceramic particles) may be ranged from 10nm to 30μm, or ranged from 500nm to 10μm, or ranged from 1μm to 3μm, to form a uniform smooth film with polymer base.

The present disclosure also studies the mixture of ceramic fillers with different thickness. In the experiments, SEBS and fillers were mixed at 200 centigrade (℃) for 30min. Then the hybrid was hot pressed at 210 centigrade (℃) to get specific film. Taking the composition of No. 2 in Table 2 as an example, wherein the AR film consists of SEBS + SrTiO ₃ + SrFe ₁₂O ₁₉ (4: 3) and the filler takes 87.5%weight percentage of the whole AR film, the transmittance of the composite AR film with different thickness thereof. Referring to Fig. 6, it is shown that the AR film with 0.51mm thickness achieves 0.2 dB improvement in 28 GHz, the AR film with 0.62 mm achieves 1.6 dB improvement in 28 GHz, and the 0.78mm AR film achieves 2.6 dB improvements in 30 GHz. It Is also shown a move trends toward the lower range of Frequency with the increase of the thickness of the AR film. Moreover, it is shown in the series of hybrid ceramics that the hybrid ceramic filled film can make the positive band of AR to a lower frequency which can decrease the required thickness of final product.

As discussed above, in practical application of the AR structure, the AR film can be disposed on the antenna module or disposed on inner/outer side of the back cover of the user’s equipment.

Material application and testing method for AR application

Taking smart phone as an example, the gap between back cover and the antenna chip in smart phone is very thin, e.g., about 0.3 to 0.8mm. Also as discussed above, the solution of the present disclosure may put the piece of AR film between the back cover and the antenna chip, or outside of the back cover. No matter what solution is adopted, the gap always has to be consideration during the application of AR film in the user’s equipment applications (see (a) and (b) of Fig. 7) .

In the embodiments regarding the gap and the user’s equipment, EIRP (Equivalent Isotropically Radiated Power) and CDF (Cumulative Distribution Function) were adopted to illustrate the transmittance and the properties of the 5G signal transmittance. In 3GPP 5G specification, the spherical coverage of user equipment (UE) is defined by CDF of EIRP. EIRP is the measure of power in a specific direction, including the transmitted power, the transmission loss in the RF chain, implementation loss, the array gain and so on. The CDF of a UE’s EIRP can be calculated through the following equation 1:

Herein, the right-hand side of the equation (1) represents the probability that the measured EIRP

of the device under test (dut) takes on a value less than or equal to a threshold EIRP value. On the other side, the EIRP is related to GAIN of antenna for antenna performance, so, the CDF of a UE’s EIRP can be transferred to the CDF of realized gain in most researches. In this embodiment, CDF of realized gain is mainly used to analyze materials’ anti-reflection performance. SEBS and BaFe ₁₂O ₁₉ are adopted as the compositions of the AR film, and the Dk was adjusted to 9.8, the Uk is 1.2, and the thickness of the AR film is 0.46mm. Since the gap between the back cover and the antenna is set to be 0.48mm in the embodiment, the gap between the back cover and the antenna is 0.02mm.

Fig. 8 shows the CDF performance simulation results for AR film insertion at different positions and different frequencies. In the drawings, the lowest line is for performance in free space, orange line is for the performance adding back cover only and the mid line is for the performance for the AR film insertion. It is obvious that the performance of AR can provide the improvement at the edge position and at the middle position both whatever at 26GHz, 28GHz and 39GHz. From the simulation results, AR film can realize the improvement for CDF performance whatever at 26GHz, 28GHz and 39GHz. The simulation is based on a 1*4 patch antenna array module with a ground, and then back cover with deco film, AR film is added to see the AR’s improvement performance for CDF of realized gain, as shown in Fig. 9.

Fig. 10 shows the CDF performance measurement results for AR film insertion at 26GHz and 28GHz. The test is finished in the millimeter-wave anechoic chamber, the similar structure and materials with Fig. 9 are used for the measure. Based on Fig. 10, the AR film’s improvement is also obvious.

According to the embodiments, the present disclosure provides at least the following solutions:

Solution 1: An anti-reflection structure, the anti-reflection structure satisfies one or more of the following features 1) and 2) :

1) the anti-reflection structure comprises at least one antireflection film with a thickness of 0.1 mm to 2 mm, preferably 0.4 to 1.2mm, wherein the antireflection film has a permittivity (Dk) of 1.3 to 40, a permeability (Uk) of 1 to 2, and a dissipation factor (Df) of 0 to 0.1, in a bandwidth with a frequency of 20-45 GHz; and/or

2) the anti-reflection structure comprises a polymer-based antireflection film the polymer-based antireflection film comprises a polymer body and 50 wt. %to 98 wt. %, preferably 70wt. %to 96 wt. %of oxide ceramic filler, based on the total weight of the polymer-based antireflection film, wherein the oxide ceramic filler is selected from one or more from the group of magneto-plumbite type magnetic ceramic, spinel type magnetic ceramic, and garnet-type magnetic ceramics.

Solution 2: the anti-reflection structure according to solution 1, wherein the antireflection film has a permittivity (Dk) of 4 to 16, a permeability (Uk) of 1.05 to 1.4, and a dissipation factor (Df) of 0 to 0.07, in a bandwidth with a frequency of 24-40 GHz.

Solution 3: the anti-reflection structure according to any one of

solution

1 or 2, wherein the anti-reflection structure comprises a single antireflection film or two or more antireflection films; alternatively, the anti-reflection structure consists of the single antireflection film or the two or more antireflection films.

Solution 4: the anti-reflection structure according to any one of solution 1 to 3, wherein the anti-reflection structure further comprises a cover disposed on the at least one antireflection film, and the at least one antireflection film achieves higher transmission than that of the cover.

Solution 5: the anti-reflection structure according to any one of solution 1 to 4, wherein the anti-reflection structure is disposed on an antenna array at a predetermined air gap of 0 mm-2 mm.

Solution 6: the anti-reflection structure according to any one of solution 1 to 5, wherein the predetermined air gap is of 0.02 mm-1.0 mm.

Solution 7: the anti-reflection structure according to any one of solution 1 to 6, wherein the antireflection film is polymer-based antireflection film, and the polymer-based antireflection film comprise one or more oxide ceramic fillers.

Solution 8: the anti-reflection structure according to any one of solution 1 to 7, wherein the oxide ceramic filler comprises single oxide ceramic fillers or a mixture of plurality of oxide ceramic fillers, preferably, the oxide ceramic fillers comprising ferrite ceramic.

Solution 9: the anti-reflection structure according to any one of solution 1 to 8, wherein the ferrite ceramic comprises magneto-plumbite type magnetic ceramic, spinel type magnetic ceramic, and garnet-type magnetic ceramics.

Solution 10: the anti-reflection structure according to any one of solution 1 to 9, wherein the ferrite ceramic comprises one or a plurality of items selected from the group consisting of Me2Fe ₁₂O ₁₉, Me3Fe ₂O _4, Me4 ₃Fe ₂Si ₃O ₁₂, wherein Me2 is selected from one or more of Ba, Pb; Me3 is selected from one or more of Mg, Mn, Ni, Fe, Cd, Cu; and Me4 is selected from one or more of Y, Sm, Eu, Dy, Tm.

Solution 11: the anti-reflection structure according to any one of solution 1 to 10, wherein the oxide ceramic filler further comprises one or a plurality of items selected from the group consisting of TiO ₂ and Me1TiO ₃, wherein Me1 is selected from one or more of Sr, Ba, Ca.

Solution 12: the anti-reflection structure according to any one of solution 1 to 11,wherein the antireflection film comprises 50 wt. %to 98 wt. %, preferably 70wt. %to 96 wt.%of oxide ceramic filler based on the total weight of antireflection film.

Solution 13: the anti-reflection structure according to any one of solution 1 to 12, wherein the antireflection film comprises 70 wt. %to 98 wt. %, preferably 70wt. %to 96 wt. %of barium ferrite (BaFe ₁₂O ₁₉) or strontium ferrite (SrFe ₁₂O ₁₉) , or 70 wt. %to 96 wt. %of the mixture of barium ferrite (BaFe ₁₂O ₁₉) and strontium ferrite (SrFe ₁₂O ₁₉) .

Solution 14: the anti-reflection structure according to any one of solution 1 to 13, wherein the polymer-based antireflection film (s) is one or a plurality of items selected from the group consisting of silicone (s) or thermal plastic polymers.

Solution 15: the anti-reflection structure according to any one of solution 1 to 14, wherein the thermal plastic polymer comprises thermal plastic elastomer (TPE) , polyethylene (PE) , polypropylene (PP) , Rubber and thermal plastic urethane (TPU) .

Solution 16: the anti-reflection structure according to any one of solution 1 to 15, wherein the polymer-based antireflection film has a thickness of 0.1 mm to 2.0 mm, preferably 0.02 mm to 1.0 mm.

Solution 17: a user equipment, comprising the anti-reflection structure or the polymer-based anti-Reflection film according to any one of claims 1-16.

Solution 18: the user equipment according to solution 17, wherein the user equipment further comprises a back cover including an inner surface and an outer surface, and the polymer-based anti-reflection film is disposed on the inner surface of the back cover or on the outer surface of the back cover.

Solution 19: the user equipment according to solution 17 or 18, the polymer-based anti-reflection film is disposed on the inner surface of the back cover, wherein the user equipment further comprises an antenna unit, a predetermined air gap between the polymer-based anti-reflection film and the antenna unit being 0 mm to 2.0 mm, preferably 0.02 mm to 1.0 mm.

Solution 20: the user equipment according to solution 17-19, wherein the polymer-based anti-reflection film is disposed on the outer surface of the back cover, wherein the user equipment further comprises an antenna unit, a predetermined air gap between the back cover and the antenna unit being 0 mm to 2.0 mm, preferably 0.02 mm to 1.0 mm.

Although the embodiments of the present disclosure are described in detail above with reference to the drawings, it should be understood that the above embodiments are only used to illustrate the present disclosure, and do not constitute a limitation to the present disclosure. For those skilled in the art, various modifications and changes may be made to the above embodiments without departing from the essence and scope of the present disclosure. Therefore, the scope of the present disclosure is limited only by the claims and their equivalent meanings.

Claims

An anti-reflection structure, the anti-reflection structure comprises at least one antireflection film with a thickness of 0.1 mm to 2 mm, preferably 0.4 to 1.2mm, wherein the antireflection film has a permittivity (Dk) of 1.3 to 40, a permeability (Uk) of 1 to 2, and a dissipation factor (Df) of 0 to 0.1, in a bandwidth with a frequency of 20-45 GHz.
The anti-reflection structure according to claim 1, wherein the antireflection film has a permittivity (Dk) of 4 to 16, a permeability (Uk) of 1.05 to 1.4, and a dissipation factor (Df) of 0 to 0.07, in a bandwidth with a frequency of 24-40 GHz.
The anti-reflection structure according to any one of claim 1 or 2, wherein the anti-reflection structure comprises a single antireflection film or two or more antireflection films; alternatively, the anti-reflection structure consists of the single antireflection film or the two or more antireflection films.
The anti-reflection structure according to any one of claim 1 or 2, wherein the anti-reflection structure further comprises a cover disposed on the at least one antireflection film, and the at least one antireflection film achieves higher transmission than that of the cover.
The anti-reflection structure according to claim 4, wherein the anti-reflection structure is disposed on an antenna array at a predetermined air gap of 0 mm-2 mm.
The anti-reflection structure according to claim 5, wherein the predetermined air gap is of 0.02 mm-1.0 mm.
The anti-reflection structure according to any one of claim 1 or 2, wherein the antireflection film is polymer-based antireflection film, and the polymer-based antireflection film comprise one or more oxide ceramic fillers.
The anti-reflection structure according to claim 7, wherein the oxide ceramic filler comprises single oxide ceramic fillers or a mixture of plurality of oxide ceramic fillers, preferably, the oxide ceramic fillers comprising ferrite ceramic.
The anti-reflection structure according to claim 8, wherein the ferrite ceramic comprises magneto-plumbite type magnetic ceramic, spinel type magnetic ceramic, and garnet-type magnetic ceramics.
The anti-reflection structure according to claim 8, wherein the ferrite ceramic comprises one or a plurality of items selected from the group consisting of Me2Fe ₁₂O ₁₉, Me3Fe ₂O ₄, Me4 ₃Fe ₂Si ₃O ₁₂, wherein Me2 is selected from one or more of Ba, Pb; Me3 is selected from one or more of Mg, Mn, Ni, Fe, Cd, Cu; and Me4 is selected from one or more of Y, Sm, Eu, Dy, Tm.
The anti-reflection structure according to claim 10, wherein the oxide ceramic filler further comprises one or a plurality of items selected from the group consisting of TiO ₂ and Me1TiO ₃, wherein Me1 is selected from one or more of Sr, Ba, Ca.
The anti-reflection structure according to claim 8, wherein the antireflection film comprises 50 wt.%to 98 wt.%, preferably 70wt.%to 96 wt.%of oxide ceramic filler based on the total weight of antireflection film.
The anti-reflection structure according to claim 10, wherein the antireflection film comprises 70 wt.%to 98 wt.%, preferably 70wt.%to 96 wt.%of barium ferrite (BaFe ₁₂O ₁₉) or strontium ferrite (SrFe ₁₂O ₁₉) , or 70 wt.%to 98 wt.%, preferably 70wt.%to 96 wt.%of the mixture of barium ferrite (BaFe ₁₂O ₁₉) and strontium ferrite (SrFe ₁₂O ₁₉) .
The anti-reflection structure according to claim 7, wherein the polymer-based antireflection film (s) is one or a plurality of items selected from the group consisting of silicone (s) or thermal plastic polymers.
The anti-reflection structure according to claim 14, wherein the thermal plastic polymer comprises thermal plastic elastomer (TPE) , polyethylene (PE) , polypropylene (PP) , Rubber and thermal plastic urethane (TPU) .
A polymer-based antireflection film, the polymer-based antireflection film comprises a polymer body and 50 wt.%to 98 wt.%, preferably 70wt.%to 96 wt.%of oxide ceramic filler, based on the total weight of the polymer-based antireflection film, wherein the oxide ceramic filler is selected from one or more from the group of magneto-plumbite type magnetic ceramic, spinel type magnetic ceramic, and garnet-type magnetic ceramics.
The polymer-based antireflection film according to claim 16, wherein the oxide ceramic comprises one or a plurality of items selected from the group consisting of Me2Fe ₁₂O ₁₉, Me3Fe ₂O ₄, Me4 ₃Fe ₂Si ₃O ₁₂, wherein Me2 is selected from one or more of Ba, Pb;Me3 is selected from one or more of Mg, Mn, Ni, Fe, Cd, Cu; and Me4 is selected from one or more of Y, Sm, Eu, Dy, Tm.
The polymer-based antireflection film according to any one of claim 16 or 17, wherein the oxide ceramic filler further comprises one or a plurality of items selected from the group consisting of TiO ₂ and Me1TiO ₃, wherein Me1 is selected from one or more of Sr, Ba, Ca.
The polymer-based antireflection film according to any one of claim 16 to 18, wherein the polymer-based antireflection film, in a bandwidth with a frequency of 20-45 GHz, having a permittivity (Dk) of 1.3 to 40, a permeability (Uk) of 1 to 2, and a dissipation factor (Df) of 0 to 0.1.
The polymer-based antireflection film according to claim 19, wherein the polymer-based antireflection film, in a bandwidth with a frequency of 24-40 GHz, having a permittivity (Dk) of 4 to 16, a permeability (Uk) of 1.05 to 1.4, and a dissipation factor (Df) of 0 to 0.07.
The polymer-based antireflection film according to any one of claim 19 or 20, wherein the polymer-based antireflection film has a thickness of 0.1 mm to 2.0 mm, preferably 0.02 mm to 1.0 mm.
A user equipment, comprising the polymer-based anti-Reflection film according to any one of claims 16-21.
The user equipment according to claim 22, wherein the user equipment further comprises a back cover including an inner surface and an outer surface, and the polymer-based anti-reflection film is disposed on the inner surface of the back cover or on the outer surface of the back cover.
The user equipment according to claim 23, the polymer-based anti-reflection film is disposed on the inner surface of the back cover, wherein the user equipment further comprises an antenna unit, a predetermined air gap between the polymer-based anti-reflection film and the antenna unit being 0 mm to 2.0 mm, preferably 0.02 mm to 1.0 mm.
The user equipment according to claim 23, the polymer-based anti-reflection film is disposed on the outer surface of the back cover, wherein the user equipment further comprises an antenna unit, a predetermined air gap between the back cover and the antenna unit being 0 mm to 2.0 mm, preferably 0.02 mm to 1.0 mm.