Communication device comprising a retroreflective structure

Abstract

The present invention relates to suppressing surface waves in a communication device (100) for a wireless communication system (500). The communication device (100) comprises a dielectric layer (106) extending along a plane (P) between a chassis (102) and a glass layer (104), an antenna element (108) configured to emit radio waves (120), and a retroreflective structure (110) extending into the dielectric layer (106) and positioned adjacent to the antenna element (108), wherein the retroreflective structure (110) is configured to reflect radio waves (120) at an angle not parallel to the plane (P). Thus, the retroreflective structure (110) prevents parasitic channeling of antenna energy into surface waves inside and behind the glass layer (104) and directs the radiation in a desired direction. By this, the radiation pattern and antenna gain are improved.

Description

Technology Field

[0001] The present invention relates to a communication device comprising a retroreflection structure for reflecting radio waves emitted by an antenna element of a communication device. Background Technology

[0002] Today, smartphones play a significant role in our daily activities not only in communication but also in media applications. Media applications can include, for example, the processing, storage, or transmission of audio or video content. Smartphones must feel compact and sturdy while remaining affordable. One popular design features an all-display structure consisting of a glass-covered, rigid metal alloy frame. Other components, such as the camera, battery, and integrated circuits, are placed beneath the glass. Furthermore, smartphones require high data transfer rates for media content transmission. Frequencies above 20 GHz, corresponding to wavelengths in the mmWave range, can be used. Implementing antennas beneath the smartphone glass is cumbersome, and radiation patterns can be disrupted, particularly at high frequencies, potentially leading to reduced antenna gain.

[0003] The objective of the embodiments of the present invention is to provide a solution that alleviates or resolves the defects and problems of conventional solutions.

[0004] The above and additional objectives are addressed by the subject matter of the independent claims. Further advantageous embodiments of the invention may be found in the dependent claims.

[0005] According to the first aspect of the present invention, the aforementioned objectives and other objectives are achieved by a communication device for a wireless communication system, and the communication device is,

[0006] Chassis (102),

[0007] glass layer,

[0008] A dielectric layer extending along the plane between the chassis and the glass layer,

[0009] An antenna element configured to emit radio waves, and

[0010] It includes a retroreflective structure that extends into the dielectric layer and is located adjacent to the antenna element — the retroreflective structure is configured to reflect radio waves at an angle not parallel to the plane —.

[0011] The retroreflective structure can be configured to have a reflection angle equal to the angle of incidence and may be additionally referred to as a reflective metasurface, an anomalous reflective metasurface, or a beam-shaped metasurface.

[0012] The fact that the retroreflective structure is located adjacent to the antenna element can be understood in this specification to mean that the interaction between the retroreflective structure and the antenna element is a so-called near-field and occurs before the radio wave forms a wavefront. The distance between the retroreflective structure and the antenna element may be, for example, less than half the wavelength of the radio wave.

[0013] Here, the dielectric layer can be understood as various components assigned between the chassis of the communication device and the glass layer. The said components of the dielectric layer vary depending on the different locations of the antenna element within the communication device. In an embodiment, the antenna element may be placed on the rear of the communication device. Non-limiting examples of the dielectric layer may include air-filled gaps between adjacent components, foam or plastic structures used as spacers, and dielectric substrates of printed circuit boards. In an embodiment, the antenna element may be placed as an edge of the communication device. Non-limiting examples of the dielectric layer may include insert molding, plastic parts, foam or plastic structures, and dielectric substrates of printed circuit boards. In another embodiment, the antenna element may be placed on the display surface of the communication device. Non-limiting examples of the dielectric layer may include structures of a display comprising a polarizer film, an adhesive film, an organic light-emitting diode (OLED) substrate, and a liquid crystal (LC) film.

[0014] The advantage of the communication device according to the first aspect is that it prevents parasitic channeling of antenna energy into surface waves inside and behind the glass layer and instead directs radiation in a desired direction. By doing so, the radiation pattern and gain of the antenna element in the communication device are improved.

[0015] In an implementation form of a communication device according to the first aspect, the back-reflection structure has non-uniform impedance along the extension in the dielectric layer.

[0016] The advantage of this implementation form is that it enables a small area of ​​the retroreflective structure (e.g., less than half a wavelength) while simultaneously improving the radiation pattern by preventing parasitic channeling of antenna energy into surface waves.

[0017] In an implementation form of a communication device according to the first aspect, a retroreflective structure is coupled to an antenna element conductively or capacitively.

[0018] The advantage of this type of implementation is that the structure is strongly excited by the near-field of the antenna element and effectively reflects radiation in the desired direction.

[0019] In an embodiment of a communication device according to the first aspect, the first end of the retroreflective structure is coupled to an antenna element conductively or capacitively.

[0020] The advantage of this embodiment is that the parasitic channel between the retroreflective structure and the antenna ground plane is eliminated. Since the retroreflective structure is coupled to the antenna element, it does not allow the excitation of the corresponding guidance mode. The guidance mode is parasitic on the antenna, and the non-radiated electromagnetic (EM) energy guided along with the dielectric layer reduces the radiated EM energy. Therefore, the disclosed embodiment further improves antenna efficiency by eliminating waves propagating along the ground plane inside the dielectric layer.

[0021] In an implementation form of a communication device according to the first aspect, the retroreflective structure is located within a range r from an antenna element with less than half the radio wave wavelength.

[0022] The advantage of this type of implementation is that the footprint of the retroreflective structure is minimized and the performance of other device components allocated under the glass is not compromised.

[0023] In an embodiment of a communication device according to the first aspect, an antenna element is arranged perpendicular to or parallel to the plane of a dielectric layer.

[0024] The advantage of this type of implementation is that the retroreflective structure can function with antennas of different configurations. For example, an antenna aperture generally parallel to the plane of the dielectric layer provides broad lateral beamforming radiation. Generally, an antenna aperture perpendicular to the plane of the dielectric layer provides end-fire beamforming radiation.

[0025] In an implementation form of a communication device according to the first aspect, the retroreflective structure has an extension into a dielectric layer of less than half the wavelength of the radio wave.

[0026] The advantage of this type of implementation is that the structure is compact and does not impair the performance of other devices located beneath the glass layer.

[0027] In the embodiment of the communication device according to the first aspect, the retroreflective structure is a conductive film.

[0028] The advantage of this implementation form is that it is easy to manufacture with patterned metal layers.

[0029] In an embodiment of a communication device according to the first aspect, the conductive film comprises a solid conductive film.

[0030] The advantage of this implementation form is that cost-effective design is possible through the manufacturing of solid conductive films.

[0031] In an embodiment of a communication device according to the first aspect, the conductive film includes a capacitive element and an inductive element that form a capacitive and inductive pattern.

[0032] The advantage of this implementation is that this arrangement can achieve the surface impedance required for the operation of the retroreflective structure. This implementation enables the design synthesis of antenna beamforming. The conductive film can be configured to reflect radio waves at an angle not parallel to the plane.

[0033] In the embodiment of the communication device according to the first aspect, the size of each capacitive element and each inductive element is less than one-fourth of the radio wave wavelength.

[0034] The advantage of this implementation is that the retroreflective structure functions as a non-uniform impedance boundary, as required for operation as a retroreflective structure. This enables a non-resonant frequency response. Therefore, for each frequency of multi-band antenna operation, radio waves are reflected in the desired direction in space and are not reflected back to the radiation source.

[0035] In the implementation form of the communication device according to the first aspect, the capacitive and inductive patterns are non-repetitive patterns.

[0036] The advantage of this implementation is that, unlike conventional periodic stopband structures that only prohibit the propagation of surface waves, the retroreflective structure can reflect waves in a desired direction. This implementation performs surface wave near-field conversion for radiated waves over short sections, for example, less than half a wavelength.

[0037] In an implementation form of a communication device according to the first aspect, capacitive and inductive patterns form a grid pattern.

[0038] The advantage of this implementation form is that multiple sets of capacitive and inductive elements can be repeated as a supercell with a longer structure to further improve performance.

[0039] In the implementation form of the communication device according to the first aspect, the radio wave is a transverse magnetic polarized radio wave.

[0040] The advantage of this type of implementation is that it functions for an antenna emitting transverse magnetic polarization radio waves. Since transverse magnetic polarization radio waves couple most strongly with parasitic surface waves along the device cover, converting transverse magnetic polarization radio waves into radiated waves enables dual polarization beamforming of the antenna.

[0041] According to a second aspect of the present invention, the aforementioned objectives and other objectives are achieved by a method for producing a communication device for a wireless communication system, and the method is,

[0042] Step of obtaining a chassis and a glass layer;

[0043] Step of obtaining a dielectric layer extending in a plane ― the dielectric layer includes a retroreflective structure extending into the dielectric layer, and the retroreflective structure is configured to reflect radio waves at an angle not parallel to the plane ―;

[0044] Step of placing a dielectric layer between the chassis and the glass layer;

[0045] A step of placing an antenna element adjacent to a retroreflective structure; and

[0046] It includes the step of coupling antenna elements to a retroreflective structure conductively or capacitively.

[0047] The method according to the second aspect may be extended to an implementation form corresponding to the implementation form of the communication device according to the first aspect. Accordingly, the implementation form of the method includes feature(s) of the corresponding implementation form of the communication device.

[0048] The advantage of the method according to the second aspect is the same as that of the corresponding implementation form of the communication device according to the first aspect.

[0049] Further applications and advantages of the embodiments of the present invention will be apparent from the following detailed description. Brief explanation of the drawing

[0050] The attached drawings are intended to clarify and explain other embodiments of the present invention. - FIG. 1 schematically illustrates a communication device according to an embodiment of the present invention, and - FIGS. 2a-b schematically illustrates a retroreflective structure and antenna elements of a communication device according to an embodiment of the present invention, - FIGS. 3a-b schematically illustrates a retroreflective structure and antenna elements of a communication device according to an embodiment of the present invention, and - Figures 4a-b illustrate the concept of back reflection, transverse magnetic mode vectors, and their projections, and - FIGS. 5a-c illustrate a retroreflective structure model according to an embodiment of the present invention, and - FIGS. 6a-b illustrate impedance discretization according to an embodiment of the present invention, - FIGS. 7a-c illustrate the geometry of a retroreflective structure according to an embodiment of the present invention, and - FIG. 8 illustrates the orientation of a conventional communication device and a communication device according to the present invention, and - FIGS. 9a-b illustrate the improvement in directivity and gain for a communication device according to the present invention, and - FIG. 10 illustrates a method for a communication device according to an embodiment of the present invention. Specific details for implementing the invention

[0051] Due to the layered structure of conventional smartphones, surface waves are excited by the internal antenna across the screen glass and the dielectric layer located beneath it. These surface waves significantly distort the antenna's radiation pattern and reduce gain, so they must be avoided.

[0052] Existing solutions for surface wave suppression can be grouped into volumetric and surface implementations. Volumetric solutions achieve wave suppression by altering the overall electrical properties of the layer materials. Common volumetric approaches for wave suppression are based on electromagnetic bandgap structures (EBGs), epsilon-negative materials (ENGs), or mu-negative materials (MNGs). Surface solutions are based on creating additional interfaces within the dielectric layer. These geometric changes modify the dispersion characteristics of surface waves that can propagate through the dielectric layer.

[0053] A more practical implementation can be achieved by using a leaky-wave antenna approach in which surface wave propagation is reduced by radiating some of the energy at the interface.

[0054] The solution mentioned above does not consider the antenna itself, but considers the characteristics of the smartphone body only as a combination of different layers. Better results can be obtained by modifying the antenna radiation pattern itself. A solution proposed in this field includes an antenna device composed of multiple radiating conductors and dummy conductors on a multilayer circuit board, and an antenna device composed of a radiator surrounded by filter cells located on the board.

[0055] Existing solutions have shown promising results in terms of radio wave suppression or improvement of antenna radiation characteristics under controlled conditions. Unfortunately, the assumptions made for each solution are incompatible with the constraints imposed by antennas located beneath the glass of full-display smartphones. Smartphone design prioritizes the display over other device characteristics. Therefore, any structures placed behind the glass must have minimal impact on display performance. These conditions require small antennas, which make it impossible to use existing surface wave suppression solutions due to the need for a large surface area.

[0056] Furthermore, some existing solutions are implemented as volumetric structures that cannot be placed behind glass without compromising antenna or display performance. In some implementations, the structure does not fit between the glass and the chassis, requiring a change in smartphone size without guaranteeing performance improvements. Additionally, the structural design must be compatible with actual manufacturing methods. However, manufacturing volumetric structures is difficult and costly, and in practice, only thin, flat material sheets can be used.

[0057] In summary, existing solutions for surface wave suppression promise excellent performance under ideal conditions. However, since it is not possible to implement these solutions compactly, they are not suitable for antennas integrated into full-display smartphones.

[0058] The objective of the present invention is to improve the performance of an antenna located behind a glass layer in a communication device using a retroreflective structure designed to reflect electromagnetic waves capable of exciting surface waves, and to resolve the aforementioned drawbacks. The retroreflective structure is arranged to prevent antenna energy from parasitizing into surface waves inside and behind the glass layer and to direct radiation in a desired direction. Accordingly, the radiation pattern and gain of the antenna in the communication device are improved.

[0059] FIG. 1 schematically illustrates a communication device (100) for a wireless communication system according to an embodiment of the present invention. The communication device (100) includes a chassis (102), a glass layer (104), and a dielectric layer (106). Referring to FIG. 1, the dielectric layer (106) extends along plane P between the chassis (102) and the glass layer (104). The dielectric layer (106) may be further referred to as a dielectric display or a dielectric spacer.

[0060] The communication device (100) further includes an antenna element (108) and a retroreflective structure (110). The antenna element (108) is configured to emit radio waves (120). In an embodiment, the radio waves (120) may be transverse magnetic polarization radio waves.

[0061] Referring to FIG. 1, the retroreflective structure (110) extends into the dielectric layer (106) and is positioned adjacent to the antenna element (108). In an embodiment, the retroreflective structure (110) may be conductively or capacitively coupled to the antenna element (108). For example, a first end of the retroreflective structure (110) may be conductively or capacitively coupled to the antenna element (108).

[0062] The retroreflective structure (110) is configured to reflect radio waves (120) emitted by the antenna element (108) at an angle not parallel to plane P. The reflection angle of the retroreflective structure (110) is equal to or substantially equal to the angle of incidence. Thus, the angle not parallel to plane P at which the retroreflective structure (110) reflects the radio waves (120) is equal to the angle at which the radio waves (120) are incident toward the retroreflective structure (110). Therefore, the retroreflective structure (110) acts as an effective boundary for reflecting radio waves (120) back from the antenna element (108) to the antenna element (108).

[0063] The reflection phase of the retroreflected radio wave can be produced by adjusting the topology of the retroreflective structure (110). According to an embodiment of the present invention, the retroreflective structure (110) has non-uniform impedance along its extension within the dielectric layer (106). In this way, desired phase synchronization between the incident surface wave and the reflected radiation wave can be ensured. Further details regarding the topology of the retroreflective structure (110) will be described below with reference to FIGS. 4 through 7.

[0064] By using a near-field region close to the antenna element (108), the retroreflective structure (110) can be used as a beam-forming surface for the antenna element (108). The near-field region can be defined as up to half the radio wave wavelength. Thus, in the embodiment, the retroreflective structure (110) can be located within a range r from the antenna element (108) for less than half the radio wave (120) wavelength. Additionally, the retroreflective structure (110) can be extended within the dielectric layer (106) for less than half the radio wave (120) wavelength.

[0065] According to an embodiment of the present invention, the retroreflective structure (110) is a conductive film (112). Accordingly, the retroreflective structure (110) may be a thin, flat structure extending into a dielectric layer (106) having a major extension along plane P. The conductive film (112) may include a solid conductive film or the conductive film (112) may include capacitive elements and inductive elements that form capacitive and inductive patterns.

[0066] In an embodiment in which the conductive film (112) comprises capacitive elements and inductive elements, the size of each capacitive element and each inductive element may be less than 1 / 4 of the wavelength of the radio wave (120). Thus, the capacitive elements and inductive elements may form capacitive and inductive patterns with sub-wavelength spacing. The capacitive and inductive patterns may also be non-repetitive patterns, for example, non-periodic patterns. In this way, resonance due to periodicity may be avoided. Additionally, the capacitive and inductive patterns may form a grid pattern. The capacitive and inductive patterns may be designed as a group of grip-impedance strips using discrete values ​​of the reflector grid impedance function, for example, as further described below.

[0067] The antenna element (108) may be positioned perpendicular to, parallel to, or in any other suitable direction with respect to plane P of the dielectric layer (106). FIGS. 2a-b schematically illustrates an embodiment in which the antenna element (108) is positioned perpendicular to plane P of the dielectric layer (106). In the embodiment illustrated in FIGS. 2a-b, the antenna element (108) is a monopole, and the retroreflective structure (110) is a conductive film (112) comprising capacitive elements (114a, 114b, ..., 114n) and inductive elements (116a, 116b, ..., 116n) forming capacitive and inductive patterns. There is a metal element of the antenna structure that blocks the volume between the conductive film (112) and the chassis / ground plane (102) to prevent the excitation of waves guided between the conductive film (112) and the chassis / ground plane (102). For example, this can be ensured by conductively coupling the antenna element (108) at the first end (110a) of the retroreflective structure (110), as shown in FIG. 2b.

[0068] FIGS. 3a-b schematically illustrates an embodiment in which an antenna element (108) is positioned parallel to plane P of a dielectric layer (106). In the embodiment illustrated in FIGS. 3a-b, the antenna element (108) is a monopole and the retroreflective structure (110) is a solid conductive film (112). The retroreflective structure (110) is additionally conductively coupled to the antenna element (108). There is a metal element of the antenna structure that blocks the volume between the conductive film (112) and the chassis / ground plane (102) to prevent the excitation of waves guided between the conductive film (112) and the chassis / ground plane (102). For example, this can be ensured by conductively coupling the antenna element (108) at the first end (110a) of the retroreflective structure (110), as illustrated in FIG. 3b.

[0069] The above-described embodiments are two examples of possible combinations of antenna element placement and retroreflective structure (110) types. However, other combinations are possible without departing from the scope of the invention. For example, the antenna element (108) may be placed perpendicular to plane P of the dielectric layer (106) and the retroreflective structure (110) may be a solid conductive film, or the antenna element (108) may be placed parallel to plane P of the dielectric layer (106) and the retroreflective structure (110) may be a conductive film (112) forming capacitive and inductive patterns.

[0070] The back-reflection structure (110), as shown in FIG. 4a, allows the redirection of waves incident from space back toward the source of the waves.

[0071] According to an embodiment of the present invention, the retroreflection structure (110) can be implemented as a metasurface capable of adjusting an engineering surface impedance defined through boundary conditions to achieve desired phase synchronization between an incident wave and a reflected wave.

[0072]

[0073] Here, and is the tangential component of the total, i.e., incident + reflected, electric field and magnetic field, and is a unit vector perpendicular to the surface. Therefore, it is essential to define the tangential components of both the electric and magnetic fields to provide the desired back-reflection effect.

[0074] Due to the desired polarization of the field, the retroreflective structure (110) can be designed for transverse-magnetic (TM) polarized waves that have no normal component of the magnetic field. Based on the coordinate definitions shown in FIG. 4b, the tangential components of the incident and reflected magnetic fields are,

[0075]

[0076]

[0077] It can be used like this,

[0078] Here is the reflection coefficient ( is the phase of the reflection coefficient) and θ is the angle of incidence. To find the electric field component of the TM wave, the field Ampere's law, which has time harmonic dependency,

[0079]

[0080] This is used,

[0081] is the permittivity of the background medium assumed to be a vacuum. Therefore, the tangential electric field

[0082]

[0083] It is induced by.

[0084] Using [Equation 1], the tangential components of the total magnetic and electric fields are the reflected and incident fields (each and If we know that it is the sum of ), the surface impedance modeling the back-reflection structure (110) is,

[0085]

[0086] It will be,

[0087] Here is the phase gradient introduced by the metasurface. The phase gradient required for the retroreflective structure (110) leads to a frequency-dependent surface impedance. From the definition of the phase gradient, the period of the retroreflective structure (110) is It is calculated as.

[0088] The period increases as the angle of incidence decreases, and at the limit where the angle is 0, i.e., at normal incidence, the retroreflective structure (110) degenerates into a normal uniform mirror. In either case, the compact retroreflective structure (110) will respond to the field near the antenna, and thus, only one period of surface impedance is required.

[0089] In the communication device (100), as illustrated in FIG. 5a-c, it becomes more convenient to generate the impedance of the retroreflective structure (110) using a glass surface as a reference. The retroreflective structure (110) located inside the dielectric layer (106) introduces a grid impedance that introduces discontinuities of the tangential magnetic field on both sides thereof. It can be modeled as.

[0090] The electromagnetic field is applied to the surface of the retroreflective structure (110). Propagates toward the back-reflection structure (110) at an angle (see FIG. 5a). Normal and tangent Incident electromagnetic field coefficient having components Is A glass cover layer having thickness, grid impedance of a conductive pattern (112) and conductive pattern (112) and ground plane It is reflected from the surface of a multilayer retroreflective structure (110) having dielectric layers between the dielectric layers. Impedance and grid impedance (Fig. 5b) is a surface impedance modeling a retroreflective structure (110) (Fig. 5c) It can be converted into.

[0091] To make the multilayer structure function as a retroreflector on a glass surface, the behavior of the surface impedance defined in [Equation 6] must be mimicked. By using a transmission line approach as illustrated in Fig. 5b, the input impedance of the multilayer system can be calculated and equated to the desired value. As a function of the surface impedance and other parameters of the multilayer system, the resulting expression of the required grid impedance is,

[0092]

[0093] It can be used like this,

[0094] Here, the genome layer Cases where numbering is used class am.

[0095] FIG. 6a illustrates the discretization of grid and surface impedance profiles. It is important to note that both grid and surface impedances are continuous functions along the surface in the x-direction. This issue can be problematic from the perspective of surface implementation because the retroreflective structure (110) is implemented as a set of finite-sized elements. Therefore, the retroreflective structure (110) is discretized into strips having constant grid impedance values, as schematically shown in FIG. 6b, thereby replacing the continuous function with a stepwise constant approximation. By selecting an appropriate number of discretized values, a suitable balance between performance and complexity can be achieved.

[0096] FIGS. 7a-c illustrate a retroreflective structure (110) according to an embodiment in which the retroreflective structure (110) is discretized into six elements. The elements may be manufactured, for example, based on a serpentine slot topology. FIG. 7a illustrates one element of the retroreflective structure (110) based on a serpentine slot. Each element comprises two metal patches (116a, 116b) separated by a gap or a slot (114a) between them. Grid impedance (Zg) can be adjusted by changing the length (A) and width (w) of the slot gap. FIG. 7b illustrates a profile of the retroreflective structure (110) along the y-axis, wherein the profile is designed to realize the desired retroreflective function.

[0097] FIG. 7c illustrates the location of the retroreflective structure (110) within the dielectric layer (106). In this embodiment, the retroreflective structure (110) is located in the middle of the dielectric layer (106) below the glass layer (104).

[0098] [Table 1] considers glass with a thickness of 0.5 mm and a relative permittivity of 5.5, and the angle of incidence when the dielectric layer (106) has the characteristics of a 1.0 mm slab with a relative permittivity of 2.7. It represents the optimal value for the inverse reflection structure (110).

[0099] [Table 1]

[0100]

[0101] In the case of the embodiment illustrated in FIG. 7c, the required optimal impedance value given in [Table 1] indicates that none of the discretized strips require operation close to resonance, and furthermore, that the retroreflective structure (110) uses only capacitive grid elements. By this, the retroreflective structure (110) can operate over a wider frequency band than other conventional structures that can only operate in a resonant region of a narrow frequency range.

[0102] In terms of size, the proposed retroreflective structure (110) is a suitable compact solution because its length is reduced to the one-phase period of [Equation 6]. In the scenario discussed above, the length of the retroreflective structure (110) is about 5.2 mm, which is less than half a wavelength at a reference frequency of 29 GHz, and each element occupies 1 / 6 of the total length. If more discretization points are used with a suitable manufacturing method, the length of the element can be reduced even further.

[0103] By using the retroreflective structure (110) according to the present invention, not only can the propagation of surface waves within the dielectric layer (106) be blocked, but such energy can also be further redirected in a desired direction as shown in FIG. 8. FIG. 8 illustrates the directivity at 29 GHz for two scenarios: a first scenario (802) showing directivity for a communication device without a structure for surface wave suppression, and a second scenario (804) showing directivity for the same communication device having an additional retroreflective structure (110) according to the present invention in the middle of the dielectric layer (106). Surface waves propagating to the lower part of the glass in the 90˚ direction are suppressed by the retroreflective structure (110) and redirected to the region of interest on the upper part of the glass, i.e., the 0˚ direction.

[0104] For different frequencies, the back-reflective structure (110) exhibits consistent improvement, as can be seen in FIGS. 9a-b. FIGS. 9a illustrates the improvement in directivity of the back-reflective structure (110), and FIGS. 9b illustrates the improvement in gain of the back-reflective structure (110). The back-reflective structure (110) can provide an average improvement in directivity of about 3 dB and a gain improvement of about 5 dB.

[0105] The present invention also relates to a method for manufacturing a communication device (100) according to any one of the described embodiments. FIG. 10 illustrates a flowchart of a method (200), the method (200) comprising the step (202) of obtaining a chassis (102) and a glass layer (104) and the step (204) of further obtaining a dielectric layer (106) comprising a retroreflective structure (110) extending from plane P and extending within the dielectric layer (106), wherein the retroreflective structure (110) is configured to reflect radio waves (120) at an angle not parallel to plane P. The method (200) further comprises the step (206) of placing the dielectric layer (106) between the chassis (102) and the glass layer (104); and the step (208) of placing an antenna element (108) adjacent to the retroreflective structure (110). This method (200) further includes the step (210) of conductively or capacitively coupling an antenna element (108) to a retroreflective structure (110).

[0106] In this specification, the communication device (100) may be represented as a user device, user equipment (UE), mobile station, internet of things (IoT) device, sensor device, wireless terminal and / or mobile terminal, and may communicate wirelessly in a wireless communication system (sometimes also referred to as a cellular wireless system). The UE may additionally be referred to as a mobile phone, cellular phone, computer tablet, or laptop having wireless capabilities. In this context, the UE may be a portable, pocket-storable, handheld, computer-containing, or vehicle-mounted mobile device capable of communicating voice and / or data with other entities, such as other receivers or servers, over a wireless access network, for example. The UE may be a station (STA), which is any device comprising an IEEE 802.11 compliant Media Access Control (MAC) and a Physical Layer (PHY) interface for Wireless Medium (WM). The UE can also be configured for communication in 5th generation wireless technologies such as 3GPP-related LTE and LTE-Advanced, WiMAX and its evolution, and New Radio.

[0107] Finally, it should be understood that the present invention is not limited to the embodiments described above, and is related to and incorporated with all embodiments within the scope of the appended independent claims.

Claims

Claim 1 A communication device (100) for a wireless communication system (500), comprising a chassis (102), a glass layer (104), a dielectric layer (106) extending along a plane (P) between the chassis (102) and the glass layer (104), an antenna element (108) configured to emit radio waves (120), and a retroreflective structure (110) extending into the dielectric layer (106) and positioned adjacent to the antenna element (108) ― the retroreflective structure (110) is configured to reflect the radio waves (120) at an angle not parallel to the plane (P) and to perform beamforming for the antenna element (108) through a near-field generated by the antenna element (108) and the retroreflective structure (110), and the retroreflective structure (110) has a non-uniform impedance along the extension of the retroreflective structure (110) within the dielectric layer (106). A communication device (100) including ―. Claim 2 In claim 1, the above retroreflective structure (110) is coupled conductively or capacitively to the antenna element (108), a communication device (100). Claim 3 In paragraph 2, the first end of the above retroreflective structure (110) is coupled conductively or capacitively to the antenna element (108), a communication device (100). Claim 4 A communication device (100) according to any one of claims 1 to 3, wherein the retroreflective structure (110) is located within a range (r) from the antenna element (108), and the range (r) is less than half the wavelength of the radio wave (120). Claim 5 A communication device (100) wherein, in any one of claims 1 to 3, the antenna element (108) is arranged perpendicularly or parallel to the plane (P) of the dielectric layer (106). Claim 6 A communication device (100) according to any one of claims 1 to 3, wherein the retroreflective structure (110) has an extension within the dielectric layer (106), and the extension is less than half the wavelength of the radio wave (120). Claim 7 A communication device (100) for a wireless communication system (500), comprising a chassis (102), a glass layer (104), a dielectric layer (106) extending along a plane (P) between the chassis (102) and the glass layer (104), an antenna element (108) configured to emit radio waves (120), and a retroreflective structure (110) extending into the dielectric layer (106) and positioned adjacent to the antenna element (108) — the retroreflective structure (110) is configured to reflect the radio waves (120) at an angle not parallel to the plane (P) and to perform beam forming for the antenna element (108) through a near-field generated by the antenna element (108) and the retroreflective structure (110) — wherein the retroreflective structure (110) is a conductive film (112). Claim 8 In claim 7, the communication device (100) is a solid conductive film (112). Claim 9 In claim 7, the conductive film (112) comprises capacitive elements (114a, 114b, ..., 114n) and inductive elements (116a, 116b, ..., 116n) forming capacitive and inductive patterns, a communication device (100). Claim 10 In claim 9, the size of each capacitive element and each inductive element is less than one-fourth of the wavelength of the radio wave (120), the communication device (100). Claim 11 A communication device (100) in which, in claim 9 or 10, the capacitive and inductive patterns are non-repetitive patterns. Claim 12 In claim 9 or 10, the capacitive and inductive patterns form a grid pattern, a communication device (100). Claim 13 In claim 9 or 10, the radio wave (120) is a transverse magnetic polarized radio wave, communication device (100). Claim 14 A method (200) for producing a communication device (100) for a wireless communication system (500), comprising the steps of: obtaining a chassis (102) and a glass layer (104) (202); obtaining a dielectric layer (106) extending from a plane (P) (204) ― the dielectric layer (106) includes a retroreflective structure (110) extending into the dielectric layer (106), wherein the retroreflective structure (110) is configured to reflect radio waves (120) at an angle not parallel to the plane (P) and to perform beam forming for the antenna element (108) through a near-field generated by the antenna element (108) and the retroreflective structure (110), and wherein the retroreflective structure (110) has a non-uniform impedance along the extension of the retroreflective structure (110) within the dielectric layer (106) ―; the chassis (102) and the A method (200) comprising the steps of: placing the dielectric layer (106) between glass layers (104) (206); placing the antenna element (108) adjacent to the retroreflective structure (110) (208); and coupling the antenna element (108) to the retroreflective structure (110) conductively or capacitively. Claim 15 A method (200) for producing a communication device (100) for a wireless communication system (500), comprising: a step (202) of obtaining a chassis (102) and a glass layer (104); a step of obtaining a dielectric layer (106) extending from a plane (P) ― said dielectric layer (106) includes a retroreflective structure (110) extending into the dielectric layer (106), said retroreflective structure (110) is configured to reflect radio waves (120) at an angle not parallel to the plane (P) and to perform beam forming for the antenna element (108) through the antenna element (108) and the near-field generated by the retroreflective structure (110), said retroreflective structure (110) is a conductive film (112); and a step (206) of placing the dielectric layer (106) between the chassis (102) and the glass layer (104). A method (200) comprising the steps of: placing the antenna element (108) adjacent to the retroreflective structure (110); and coupling the antenna element (108) to the retroreflective structure (110) conductively or capacitively.

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