Device for reflecting and / or transmitting electromagnetic radiation

Abstract

The invention relates to a device (100) for the reflection and / or transmission of electromagnetic radiation, comprising a plurality of phase-shift structures (110) arranged on a surface (120); wherein the distance between any two adjacent phase-shift structures (110) is less than twice the free-space wavelength corresponding to a predetermined lower cutoff frequency; wherein each phase-shift structure (100) comprises at least one phase-shift element (111) configured as a passive dielectric component and configured to cause a phase shift of an electromagnetic wave propagated through the phase-shift element (111);wherein at least one property of the respective phase shift element (111) related to a respective phase shift by a respective phase shift element (111) depends on a position of the respective phase shift element (111) with respect to the surface (120), such that a respective phase shift of a respective part of the reflected and / or transmitted electromagnetic radiation caused by the device (100) depends on a respective location with respect to the surface (120) at which the respective part of the reflected and / or transmitted electromagnetic radiation hits the device (100).

Description

Technical field

[0001] The invention relates to a device for the reflection and / or transmission of electromagnetic radiation. background

[0002] With the new 5G and subsequent 6G mobile communication generations, increasingly higher frequency ranges above 7 GHz, particularly in the millimeter wave range above 24 GHz, are being used. These have different propagation characteristics and generally require a direct line of sight between transmitter and receiver to ensure the desired data transmission rate. To cover areas with poor coverage, additional cell towers or repeaters can be used, but these are expensive and require power connections and, if necessary, a data line. Finding and obtaining approval for a suitable location to install the cell tower or repeater can also be challenging.

[0003] For the next generation of mobile communications, 6G, so-called Reconfigurable Intelligent Surfaces (RIS) are being developed, which can reflect incoming signals in virtually any direction. Implementations can be based on a periodic arrangement of radiating elements, such as patch antennas, on a printed circuit board (PCB). The adjustment, i.e., the (re)configurability, can be achieved using diodes or liquid crystal elements.The disadvantages of these solutions lie in the ohmic losses in the metal structures, the limitation to phase shifts between 0° and 180°, in some cases an undesired amplitude variation associated with the phase adjustment (similar to the variation in amplitude of a Lorentz curve when shifting the resonant frequency to varying the phase from 0° to 180° at a given operating frequency), and the limitation to the flatness of the printed circuit board, meaning that such RISs can only be mounted on flat surfaces, not curved shapes, without causing unwanted interference. Furthermore, they can only cover a relatively narrow frequency range.

[0004] Against this background, there is a need for a cost-effective device for the reflection and / or transmission of electromagnetic radiation that reflects or transmits at least as large a proportion of the incident signal's power as possible in the desired direction, thus minimizing losses due to dissipation (e.g., ohmic losses) or reflections in undesired directions (e.g., specular reflection, such as occurs at interfaces between air and a printed circuit board surface or a dielectric plate). Furthermore, the device should offer flexibility in its application, not being limited to flat surfaces but also capable of being applied to curved surfaces with good surface contouring. In particular, the device should be able to conform to a curved surface and still function as required.

[0005] Based on this, the present invention aims to provide a device for reflecting and / or transmitting electromagnetic radiation that overcomes the described disadvantages. In particular, the present invention aims to provide a device for reflecting and / or transmitting electromagnetic radiation that offers flexibility in terms of its mounting, can reflect incident signals in any direction, and in particular can cover a frequency range typical for mobile communication bands (e.g., band n258: 24.25 GHz to 27.5 GHz), exhibits high efficiency, and is cost-effective and as flat as possible. Furthermore, this device should offer the flexibility to be mounted not only on flat surfaces but also on curved surfaces with good surface contouring. Description of the invention

[0006] The problem is solved by a device according to the invention for the reflection and / or transmission of electromagnetic radiation, comprising a plurality of phase-shift structures arranged on a surface.

[0007] The spacing between any two adjacent phase-shift structures is less than twice the free-space wavelength corresponding to a predetermined lower cutoff frequency. This allows, in particular, the achievement of a desired radiation direction, minimization of side lobes (grating lobes), and maximization of directivity and gain in the main radiation direction (main lobe). The calculation, especially in the case of periodicity, can preferably be kept simple, and spatial aliasing can be avoided. At the same time, the coupling between the antenna elements can be managed.

[0008] Each of the numerous phase-shift structures comprises at least one phase-shift element, which is designed as a passive dielectric component and is configured to cause a phase shift of an electromagnetic wave propagating through the phase-shift element. Specifically, an incident wave is decomposed into elementary waves according to Huygens' principle. These elementary waves propagate through the at least one phase-shift element, particularly through multiple differently configured elements, experiencing different phase delays. As a result, they emerge as elementary waves with different phase angles, which then superimpose according to Huygens' principle to form a single wave. The wavefront of this wave can now be inclined according to the phase angles, as shown in [reference to relevant figure]. Fig. 3a and Fig. 3b illustrated.

[0009] At least one property of the respective phase shift element, which is related to a respective phase shift by a respective phase shift element, depends on a position of the respective phase shift element with respect to the surface, such that a respective phase shift of a respective part of the reflected and / or transmitted electromagnetic radiation caused by the device depends on a respective location with respect to the surface where the respective part of the reflected and / or transmitted electromagnetic radiation hits the device.

[0010] It has been shown that the device according to the invention for reflecting and / or transmitting electromagnetic radiation enables the reflection and / or transmission of incident electromagnetic waves (and the signals transmitted with them) in adjustable, virtually freely selectable directions, in order to circumvent obstacles, interference, or blockages that already exist at higher frequencies, particularly frequencies above 6 GHz, when there is no line of sight between transmitter and receiver (e.g., due to plants, walls, or other objects). Unlike, for example, a repeater, which also attempts to circumvent obstacles, this device requires essentially no energy and, in particular, unlike an ordinary mirror, can still transmit the signal in the desired direction. The device according to the invention is therefore also independent of the availability of power connections.Furthermore, the device according to the invention makes it possible to direct at least a large part of the incident electromagnetic wave in the desired direction by minimizing dissipation (e.g., due to ohmic losses) and losses due to specular reflection or unwanted sidelobes (side lobes of the radiation). At the same time, both polarization directions that the incident electromagnetic wave can have and that can be used for signal transmission are supported.

[0011] It was found that the device according to the invention achieves the phase shift, which varies from location to location on the surface, by means of an arrangement of, in particular, dielectric, phase-shift structures. A mode is excited on the phase-shift structure, especially by an incident electromagnetic wave, which propagates through the phase-shift structure and thereby undergoes a phase shift. Depending on, for example, the length of the phase-shift structure, the phase shift can be adjusted. A good match to the free-space wave can be achieved, resulting in virtually no specular reflections at the interface between free space and the dielectric surface.Furthermore, ohmic losses, such as those occurring in the patches of a printed circuit board-based RIS, can be avoided by, in particular, not using any metallic structures (except for a possible reflective element), especially those on which resonant peaks with correspondingly higher losses develop. This can prevent specular losses as well as ohmic losses and, with suitable dimensioning of the dielectric structures, enable "true time delay," i.e., maintaining the phase precisely across the entire device and not just a maximum of 180° or 100°.Enabling 360° phase shifts (because if the phase of the edge rays striking opposite edges of the device is shifted relative to each other by multiples of 360°, a constructive superposition in the desired direction results for an unmodulated wave; however, if the symbol length is shorter than the shift by multiples of 360°, only a reduced signal arrives at the receiver). The ability to implement "true time delay," i.e., phase shifts of multiples of 360°, also enables conformal devices, especially metasurfaces, which can be mounted on curved surfaces (whereas PCB-based solutions are only suitable for flat surfaces). It has been recognized, in particular, that the device can compensate for path differences that an incident, planar wavefront exhibits at different points on a curved surface.In particular, the phase shift structures can also be used to ensure that the height of the device, i.e. the dimension perpendicular to the surface, remains low, especially by adjusting the phase shift per unit length by selecting the dimensions of the phase shift elements, especially the dielectric ones.

[0012] Compared to other RIS, which are mostly implemented on the basis of printed circuit boards, the described solution offers the advantage of avoiding ohmic losses and being better suited for higher frequencies through the use of dielectrics, thus also being suitable for the frequency ranges above 30 GHz considered with 6G, especially since dielectric losses decrease with higher frequency, while ohmic losses in metal structures increase with the square root of the frequency.

[0013] Furthermore, this solution overcomes the limitation to phase shifts between 0° and 180° and does not exhibit any significant change in amplitude when the phase changes (as is characteristic of RIS based on resonant elements with continuous variation of the phase (i.e., not just switching the phase between 0° and 180° as in so-called digital RIS)).

[0014] Furthermore, in particular, not only a reflective but also a transmitting RIS is feasible, which can reduce path losses in various scenarios.

[0015] According to an advantageous embodiment of the device according to the invention, the surface on which the phase-shift structures are arranged is at least partially flat and / or at least partially curved. This allows the device to be mounted, in particular, flush with the surface on flat and / or curved surfaces, such as walls or ceilings, without protruding into the room. By enabling "true time delay," the proposed metasurface can also be designed for curved surfaces and allows for wavefront shaping, thus enabling its use near antennas, e.g., to transform spherical wavefronts into plane waves, similar to a parabolic mirror, and in particular without being curved as extensively as a parabolic mirror, but rather extending flatly alongside the antenna.

[0016] According to a further advantageous embodiment of the device according to the invention, the phase-shift structures are arranged at least sectionally regularly and / or at least sectionally irregularly on the surface. Preferably, the device comprises a regular arrangement of, in particular dielectric, phase-shift structures on a flat or curved surface at intervals of at least substantially half the free-space wavelength of the electromagnetic waves for which the device is designed.

[0017] According to a further advantageous embodiment of the device according to the invention, a spatial region between the phase-shift structures is filled with a dielectric. The space between the phase-shift structures, particularly dielectric ones, can be filled with a dielectric, especially one with a significantly lower dielectric constant, for example, a polymer, a foam, or the like. In this way, for example, a mechanical connection between the phase-shift structures, particularly dielectric ones, can be realized in a transmitting device. In particular, the overall thickness of the device can also be reduced by increasing the phase shift per unit length through the phase-shift structures, particularly dielectric ones.

[0018] According to a further advantageous embodiment of the device according to the invention, the at least one phase-shifting element is designed as a dielectric waveguide and / or comprises at least one first dielectric resonator. The at least one dielectric phase-shifting element can be constructed like a dielectric waveguide or resonator, for example as a cylinder or cuboid made of a dielectric with a higher dielectric constant. Suitable materials include, for example, 3D-printable plastics, particularly those filled with ceramic particles, especially with a dielectric constant adjustable via the filler density, or ceramic dielectrics, which are produced, for example, after sintering a 3D-printed structure of ceramic particles in a polymer matrix with a binder. In particular, a cylinder or cuboid can act as a resonator if its length leads precisely to the formation of a standing wave between the open ends where reflection can occur.

[0019] Preferably, the at least one phase-shifting element comprises at least one further dielectric resonator, wherein the at least one first dielectric resonator is coupled to the at least one further dielectric resonator. In this way, a bandpass or bandstop filter is formed. By coupling resonators, a larger bandwidth can be achieved than with a single resonance. In addition, a certain degree of frequency selectivity is given, especially compared to a waveguide. For example, a supporting structure, particularly with a low dielectric constant, can be arranged between the individual dielectric resonators. For example, the spaces between individual resonators can be filled with plastic.

[0020] According to a further advantageous embodiment of the device according to the invention, the at least one phase-shifting element is at least partially, and at least substantially, spherical, cylindrical, and / or cuboidal. A spherical embodiment of a phase-shifting element is, in particular, a resonator. A cylindrical or cuboidal embodiment of a phase-shifting element can, in particular, either be resonant or function as a waveguide. The symmetry of circular or square cross-sections is particularly advantageous so that the two polarization directions that an incident wave can have experience the same phase shift, i.e., in particular so that two identical modes with the same, but rotated by 90°, orientation of the field distribution can be excited.It is conceivable, for example, that the at least one first dielectric resonator and / or the at least one further dielectric resonator is at least substantially spherical, cylindrical, and / or cuboidal. The at least one first dielectric resonator and / or the at least one further dielectric resonator could, for example, comprise a dielectric sphere or a dielectric cylinder.

[0021] According to a further advantageous embodiment of the device according to the invention, the at least one property of the respective phase shift element associated with a respective phase shift by a respective phase shift element comprises at least one of: - a length of the respective phase shift element; - a height of the respective phase shift element; - a width of the respective phase shift element; - a diameter of the respective phase shift element; - a dielectric constant of the respective phase-shift element.

[0022] The phase-shift structures, in particular the phase-shift elements, cause a phase shift that varies from location to location on the surface, especially in the form of a phase shift gradient across the surface. For this purpose, the phase-shift structures, especially the phase-shift elements, can have, for example, different lengths, diameters, and / or different dielectric constants. The phase shift on a waveguide is given in particular as β.L, where L is the length and β is the propagation constant of the excited mode. For a given frequency, the propagation constant depends in particular on the width or diameter and the dielectric constant.If the phase shift element consists, for example, of at least two resonators coupled together, particularly to form a filter, such that the total length is a multiple of the height of a single resonator plus the spacing between the resonators, the height and / or diameter or width of the resonators can be varied to achieve different phase shifts.

[0023] According to a further advantageous embodiment of the device according to the invention, the at least one phase-shifting element has at least one notch. By varying the diameter or width of the phase-shifting element, jumps in the characteristic impedance of a dielectric waveguide are induced. It has been observed that waves with shortened wavelengths propagate on stepped-impedance lines consisting of a sequence of such impedance jumps, particularly on stepped-impedance lines based on dielectric waveguides. By shortening the wavelength λ m = 2π / β m More phase change per unit length can be achieved. A notch in a resonant dielectric structure allows for suitable adjustment of the resonant frequency.

[0024] According to a further advantageous embodiment of the device according to the invention, the spatial extent of each of the plurality of phase-shift structures in at least one, preferably in each, spatial direction is smaller than the spatial extent of the surface on which the phase-shift structures are arranged in at least one, preferably in each, spatial direction.

[0025] According to a further advantageous embodiment of the device according to the invention, the respective distance between each of the two adjacent phase shift structures is between 20% and 80%, preferably approximately 50%, of the free-space wavelength corresponding to the predetermined lower cutoff frequency.

[0026] According to a further advantageous embodiment of the device according to the invention, the at least one phase-shifting element comprises at least one plastic filled with ceramic particles and / or at least one ceramic dielectric. In particular, the at least one phase-shifting element consists of at least one plastic filled with ceramic particles and / or at least one ceramic dielectric. This makes it possible, in particular, to achieve a dielectric constant suitable for reducing the wavelength of the mode that forms on the dielectric structure, so that with a shortened wavelength λ m = 2π / β m a corresponding amount of phase change per unit length can be achieved.

[0027] According to a further advantageous embodiment of the device according to the invention, each of the plurality of phase-shift structures further comprises the following: - at least one receiving element for receiving the electromagnetic radiation into the phase-shift structure; and / or - at least one reflective element for reflecting the electromagnetic radiation within the phase-shift structure; and / or - at least one transmission element for the transmission of electromagnetic radiation within the phase-shift structure; and / or - at least one radiating element for emitting the electromagnetic radiation from the phase-shift structure.

[0028] At least one receiving element can be provided to receive the electromagnetic radiation into the phase-shift structure. This receiving element can, in particular, reduce unwanted specular reflection at the interface between free space and the surface of the phase-shift structures by transforming the incident free-space wave into the mode that is intended to form on each individual phase-shift structure. A receiving element can, for example, be a hemisphere with a larger, smaller, or equal radius, such as a waveguide cylinder, or even just a spherical segment.

[0029] At least one reflection element can be provided for reflecting the electromagnetic radiation within the phase-shift structure. This reflection element can, for example, comprise a metal surface. It can also be a metal plate. Alternatively, the reflection element can be a frequency-selective surface (FSS) whose center frequency can be shifted, for example, by a liquid crystal plate or by diodes, allowing switching between reflection and transmission. The reflection element is, in particular, arranged on the underside of a phase-shift element, especially a dielectric one.In this way, a reflective device can be provided in particular.

[0030] For the transmission of electromagnetic radiation within the phase-shift structure, at least one transmission element can be provided. In particular, a transformation structure, e.g., in the form of a hemisphere (especially a dielectric one), can be applied to the upper surface of at least one phase-shift element. This structure can reduce specular reflection overall and / or the difference in reflection between the two polarization directions (with the transverse-electrical (TE) or transverse-magnetic (TM) orientation). For example, at least one transformation element and one phase-shift element can be provided for a transmitting device.

[0031] At least one emitting element can be provided to radiate the electromagnetic radiation from the phase-shift structure.

[0032] The radiating element, particularly its shape, determines the radiation characteristics, i.e., especially the angular dependence of the radiation from the arrangement of elements, while the function of a transformation element is, in particular, to adapt the field distribution of the electric and magnetic fields of the mode to the phase-shift structure and the field distribution within the radiating element. The radiating element can, for example, be a spherical segment and the transformation element a cylinder.

[0033] According to a further advantageous embodiment of the device according to the invention, a mode, preferably a HEE mode, forms on each of the plurality of phase-shift structures, which can occur in two orthogonal orientations. A mode, i.e., a field distribution pattern in which the electric field (and correspondingly also the magnetic field orthogonal to it) can be oriented in two mutually perpendicular directions, can be excited by both polarization directions of a linearly polarized wave and thus also by circularly polarized waves, and causes the same phase-shifting effect for all polarizations. Modes such as TE or TM, on the other hand, in which the electric or magnetic field lines run circularly or star-shaped, can hardly be excited by a plane wave (in which the electric and magnetic fields point in the same direction over the entire surface and thus also over each phase-shift element).

[0034] The preferred embodiments described above in this description shall also be understood as disclosed in all combinations with one another. Further advantageous preferred embodiments can be found in the following detailed description of some preferred embodiments, particularly in conjunction with the figures. Brief description of the characters

[0035] The invention is explained in more detail below with reference to some drawings. These show: Fig. 1 a schematic representation of an exemplary radio scenario; Fig. 2a a schematic perspective view of an embodiment of a device according to the invention; Fig. 2b a schematic perspective view of a further embodiment of a device according to the invention; Fig. 3a a schematic representation of a reflection of electromagnetic radiation at three exemplary phase-shift elements (111a-111c) with different lengths w or (w+Δw) or (w+2Δw); Fig. 3b a schematic representation of a reflection of electromagnetic radiation at four exemplary phase-shift elements (111a to 111d) as a superposition of elementary waves with different phase shifts emanating from each phase-shift element; Fig. 4 a schematic representation of a dispersion relation of an exemplary phase-shift element designed as a dielectric waveguide; Fig. 5 a schematic representation of a relationship between an angle of incidence and an angle of reflection of reflected electromagnetic radiation for exemplary phase shift elements with lengths stepped by Δw; Fig. 6 a schematic perspective view of an embodiment of a device according to the invention; Fig. 7-9 schematic perspective views of exemplary phase shift structures; Fig. 10-14 schematic perspective views of exemplary phase shift elements; Fig. 15 a schematic representation of an exemplary scenario in which several exemplary devices according to the invention are used by way of example, e.g. to circumvent blockages of sight lines (4a, 4b); Fig. 16a,b schematic representations of further exemplary scenarios in which a ( Fig. 16a) or two ( Fig. 16b) Exemplary devices according to the invention may be used by way of example; Fig. 17a-c schematic representations of further exemplary scenarios in which a ( Fig. 17a, Fig. 17c) or two ( Fig. 17b) Exemplary devices according to the invention may be used by way of example. Detailed description of some preferred embodiments

[0036] Fig. Figure 1 shows a schematic representation of an exemplary radio scenario in which a base station 2 attempts to transmit radio signals (an example of electromagnetic radiation) to several end devices 1a-1e, particularly mobile devices. While there is a line of sight (LOS) 5a, 5b, 5c to end devices 1b, 1d, and 1e, there is no line of sight to end devices 1a and 1c from the base station 2's perspective due to obstacles 3a and 3b (see reference symbols 4a and 4b). The tree 3a and the building 3b block the line of sight to receivers 1a and 1c, respectively (paths 4a and 4b), while there is a line of sight (LOS) to receivers 1b, 1d, and 1e via paths 5c, 5b, and 5a, respectively.

[0037] Fig. Figure 2a shows a schematic perspective view of an embodiment of a device 100 according to the invention. The device 100 comprises a plurality of phase-shift elements 111 arranged on a surface 120. The phase-shift elements 111 are designed as circular cylindrical dielectric waveguides with different heights. The height of each phase-shift element 111 (an example of a property related to a phase shift by a phase-shift element) depends on the position of the phase-shift element relative to the surface 120.In this way, the phase shift of a particular portion of electromagnetic radiation striking the device 100 depends on the location, relative to the surface 120, at which the respective portion of the electromagnetic radiation strikes the device 100. Within the device 100, the height of the phase shift elements 111 changes according to a gradient, in particular a single gradient.

[0038] Fig. Figure 2b shows a schematic perspective view of a further embodiment of a device 100' according to the invention. Like the device 100, the device 100' comprises a plurality of phase-shifting elements 111' arranged on a surface 120' and designed as circular cylindrical dielectric waveguides of different heights. Furthermore, in the device 100' as well, the height of each phase-shifting element 111' depends on its position relative to the surface 120', so that each phase shift of a portion of electromagnetic radiation incident on the device 100' caused by the device 100' also depends on the location relative to the surface 120' where the portion of the electromagnetic radiation incidents on the device 100'.Unlike in device 100, the height of the phase shift elements 111' in device 100' changes according to several, in particular stepped, gradients.

[0039] Fig. Figure 3a shows a schematic representation of the reflection of electromagnetic radiation 10 by three exemplary phase-shift elements 111a-111c. The incident electromagnetic radiation 10 is a plane electromagnetic wave. The phase-shift elements 111a-111c are cylindrical dielectric waveguides of different heights. There is a distance d between each pair of adjacent phase-shift elements 111a-111c. Phase-shift element 111a has a height w, phase-shift element 111b a height w+Δw, and phase-shift element 111c a height w+2Δw. The angle of reflection χ of the electromagnetic radiation 10" reflected by the phase-shift elements 111a-111c differs from the angle of incidence α of the electromagnetic radiation 10.In other words, the phase-shifting elements 111a-111c cause a reflection in which the angle of reflection χ of the reflected electromagnetic radiation 10" deliberately deviates from the angle of incidence α.

[0040] Fig. Figure 3b shows a schematic representation of the reflection of electromagnetic radiation at four exemplary phase-shift elements. The phase-shift elements 111a-111d are designed as circular cylindrical dielectric waveguides with different heights. There is a distance d between each pair of adjacent phase-shift elements 111a-111d. The reflection angle χ of the electromagnetic radiation 10" reflected by the phase-shift elements 111a-111d differs from a corresponding incidence angle of the electromagnetic radiation (in Fig. 3b not shown) from.

[0041] In particular, an incident wave is decomposed into elementary waves according to Huygens' principle. These elementary waves propagate through the individual, differently adjusted phase-shift elements 111a-111d and experience different phase delays, so that upon exiting, they represent elementary waves with different phase angles. These elementary waves then superimpose again according to Huygens' principle to form a wave whose wavefront can now be inclined according to the phase angles, as shown in Fig. 3a and Fig. 3b illustrated.

[0042] Fig. Figure 4 shows a schematic representation of a dispersion relation of an exemplary phase-shifting element, namely a circular cylindrical dielectric waveguide as in the Fig. 2a, Fig. 2b, Fig. 3a and Fig. Figure 3b shows. Line 21 shows a dispersion relation according to the equation f = βc / 2π, with frequency f, phase constant β, and speed of light c. Furthermore, λ = c / f, where wavelength λ is the given value. Curve 22 shows a dispersion relation β m (f) of a circular cylindrical dielectric waveguide for a mode m. A phase shift φ achieved along a length L is given by φ = β m (f) · L = 2π · L / λ m with wavelength λ m for fashion m.

[0043] Fig. Figure 5 shows a schematic representation of the relationship between the angle of incidence (represented on the x-axis) and the angle of reflection (represented on the y-axis) of reflected electromagnetic radiation for exemplary phase-shift elements. The family of curves shown in Figures 30-35 illustrates the relationship between the angle of incidence and the angle of reflection of reflected electromagnetic radiation for circular cylindrical dielectric waveguides with different heights and a respective height difference Δw between two adjacent waveguides between 0 and 0.5 mm.

[0044] Fig. Figure 6 shows a schematic perspective view of an embodiment of a device 100 according to the invention. The device 100 comprises six phase-shift structures 110 arranged on a surface 120 (for clarity, only phase-shift structures 110a and 110b are provided with reference numerals). Each of the six phase-shift structures 110 comprises a respective phase-shift element 111 and a respective reflection element 113 (an example of the at least one reflection element for reflecting the electromagnetic radiation within the phase-shift structure). The phase-shift elements 111 are designed as circular cylindrical dielectric waveguides with different heights. For example, the height of phase-shift element 111a is greater than the height of phase-shift element 111b.Consequently, any phase shift caused by the device 100 of a respective part of electromagnetic radiation striking the device 100 depends on a respective location with respect to the surface 120 where the respective part of the electromagnetic radiation strikes the device 100.

[0045] Fig. 7, Fig. 8 and Fig. Figures 9 each show a schematic perspective view of an exemplary phase shift structure 110.

[0046] The in Fig. The phase-shift structure 110 shown in Figure 7 comprises a phase-shift element 111, a receiving element 112, and a reflecting element 113. The receiving element 112 is configured to receive the electromagnetic radiation into the phase-shift structure 110 and reduces the unwanted specular reflection at the interface between free space and the surface of the phase-shift structure 110. The reflecting element 113 is suitable for reflecting the electromagnetic radiation within the phase-shift structure 110 and is arranged on the side of the phase-shift element 111 facing away from the receiving element 112.

[0047] The in Fig. The eight phase-shift structures 110a-c shown each comprise a phase-shift element 111a-c and a receiving element 112a-c. The phase-shift element 111a-c is cylindrical, while the receiving element 112a-c is hemispherical.

[0048] The in Fig. The phase shift structure 110 shown in Figure 9 comprises a phase shift element 111, a receiving element 112 and a reflection element 113. The receiving element 112 is hemispherical.

[0049] Fig. 10, Fig. 11, Fig. 12, Fig. 13 and Fig. Figure 14 each shows a schematic perspective view of exemplary phase shift elements. For example, the one in Fig. The phase shift element 111 shown has notches 50a-d. Varying the diameter causes jumps in the characteristic impedance. The [missing information] Fig. The phase shift element 111 shown uses notches 60a-c in a resonant dielectric structure, in particular enabling a suitable adjustment of the resonance frequency.

[0050] Fig. Figure 15 shows a schematic representation of an exemplary scenario in which several exemplary devices 100a-100e according to the invention are used by way of example. For instance, the devices 100a-100e are those described in Fig. 2a and / or in Fig. 2b Devices shown 100, 100'.

[0051] Also Fig. Figure 16a shows an exemplary scenario in which an exemplary device 100 according to the invention is used by way of example. Fig. Figure 16b shows an exemplary scenario in which two exemplary devices 100 according to the invention are used by way of example.

[0052] Fig. 17a and Fig. Figure 17c shows further exemplary scenarios in which an exemplary device 100 according to the invention is used by way of example. Fig. Figure 17b shows another exemplary scenario in which two exemplary devices 100 according to the invention are used by way of example. Reference symbol list 1 Mobile device 2 base stations 3 Obstacle 4. Interrupted line of sight 5 Uninterrupted line of sight 6 light sensor 7 Wall 8 buildings 9 vehicles 10 Incident electromagnetic radiation 10' Reflection of the incident electromagnetic radiation 10" Reflected electromagnetic radiation 21 Even 22 Curve 30-35 curves 40 Axis of symmetry 50 constriction 51 Wide section 60 Vertical gap 70 cross gap 100, 100' Device 110 Phase shift structure 111, 111' Phase shift element 112 Recording element 113 Reflection element 120, 120' area

Claims

[1] Device (100, 100') for reflecting and / or transmitting electromagnetic radiation, comprising a plurality of phase-shifting structures (110) arranged on a surface (120, 120'); - wherein each distance between any two adjacent phase-shift structures (110) is less than twice the free-space wavelength corresponding to a predetermined lower cutoff frequency; - wherein each of the plurality of phase-shift structures (110) comprises at least one phase-shift element (111, 111') which is designed as a passive dielectric component and which is configured to cause a phase shift of an electromagnetic wave propagated through the phase-shift element (111, 111'); - wherein at least one property of the respective phase shift element (111, 111') related to a respective phase shift by a respective phase shift element (111, 111') depends on a position of the respective phase shift element (111, 111') with respect to the surface (120, 120'), such that a respective phase shift of a respective part of the reflected and / or transmitted electromagnetic radiation caused by the device (100, 100') depends on a respective location with respect to the surface (120, 120') where the respective part of the reflected and / or transmitted electromagnetic radiation hits the device (100, 100'). [2] Device (100, 100') according to claim 1, wherein the surface (120, 120') on which the phase-shift structures (110) are arranged is at least partially planar and / or at least partially curved. [3] Device (100, 100') according to one of the preceding claims, wherein the phase-shift structures (110) are arranged at least sectionally regularly and / or at least sectionally irregularly on the surface (120, 120'). [4] Device (100, 100') according to one of the preceding claims, wherein a spatial region between the phase-shift structures (110) is filled with a dielectric. [5] Device (100, 100') according to one of the preceding claims, wherein the at least one phase-shifting element (111, 111') is designed as a dielectric waveguide and / or comprises at least one first dielectric resonator. [6] Device (100, 100') according to claim 5, wherein the at least one phase-shifting element (111, 111') comprises at least one further dielectric resonator, wherein the at least one first dielectric resonator is coupled to the at least one further dielectric resonator. [7] Device (100, 100') according to one of the preceding claims, wherein the at least one phase shift element (111, 111') is at least sectionally at least substantially spherical, cylindrical and / or cuboidal. [8] Device (100, 100') according to one of the preceding claims, wherein the at least one property of the respective phase shift element (111, 111') relating to a respective phase shift by a respective phase shift element comprises at least one of: - a length of the respective phase shift element (111, 111'); - a height of the respective phase shift element (111, 111'); - a width of the respective phase shift element (111, 111'); - a diameter of the respective phase shift element (111, 111'); - a dielectric constant of the respective phase-shift element (111, 111'). [9] Device (100, 100') according to one of the preceding claims, wherein the at least one phase shift element (111, 111') has at least one notch. [10] Device (100, 100') according to one of the preceding claims, wherein a spatial extent of each of the plurality of phase-shift structures (110) in at least one, preferably in each, spatial direction is smaller than a spatial extent of the surface (120, 120') on which the phase-shift structures (110) are arranged in at least one, preferably in each, spatial direction. [11] Device (100, 100') according to one of the preceding claims, wherein the respective distance between each of the two adjacent phase-shift structures (110) is between 20% and 80%, preferably approximately 50%, of the free-space wavelength corresponding to the predetermined lower cutoff frequency. [12] Device (100, 100') according to one of the preceding claims, wherein the at least one phase-shifting element (111, 111') comprises or consists of at least a plastic filled with ceramic particles and / or at least a ceramic dielectric. [13] Device (100, 100') according to one of the preceding claims, wherein each of the plurality of phase-shift structures (110) further comprises: - at least one receiving element for receiving the electromagnetic radiation into the phase-shift structure (110); and / or - at least one reflection element (113) for reflecting the electromagnetic radiation within the phase-shift structure (110); and / or - at least one transmission element for the transmission of electromagnetic radiation within the phase-shift structure (110); and / or - at least one radiating element for emitting the electromagnetic radiation from the phase-shift structure (110). [14] Device (100, 100') according to one of the preceding claims, wherein a mode, preferably a HEE mode, is formed on each of the plurality of phase-shift structures (110) which can occur in two orthogonal orientations.

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