Device for reflecting and / or transmitting electromagnetic radiation

Abstract

The invention relates to a device (100) for reflecting and / or transmitting electromagnetic radiation, comprising a plurality of phase-shifting structures (110) which are provided on a surface (120); a respective distance between each pair of adjacent phase-shifting structures of the plurality of phase-shifting structures (110) being less than double a free-space wavelength corresponding to a specified lower limit frequency; each of the plurality of phase-shifting structures (100) comprising at least one phase-shifting element (111) which is designed as a passive dielectric component and which is designed to bring about a phase shift of an electromagnetic wave propagating through the phase-shifting element (111); at least one property of a respective phase-shifting element (111) related to a respective phase shift carried out by the respective phase-shifting element (111) being based on the position of the respective phase-shifting 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, said phase shift being caused by the device (100), is based on the respective location on the surface (120) at which the respective part of the reflected and / or transmitted electromagnetic radiation is incident on the device (100).

Description

[0001] Device for Reflecting and / or Transmitting Electromagnetic Radiation Technical Field The invention relates to a device for reflecting and / or transmitting electromagnetic radiation. Background With the new mobile communication generations 5G and subsequently 6G, increasingly higher frequency ranges above 7 GHz, especially in the millimeter wave range above 24 GHz, are being used. These have different propagation characteristics and usually require a line of sight between transmitter and receiver to ensure the desired data transmission rate. To cover shadowed areas, additional radio cells or repeaters can be used, but these are expensive and require connections for power and, if necessary, a data line. Finding and obtaining approval for a suitable location to install the radio cell or repeater can also be challenging.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 (corresponding to the variation in amplitude of a Lorentz curve when shifting the resonant frequency to vary 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 on curved shapes, without causing unwanted interference. Furthermore, they can only cover a relatively narrow frequency range. 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 power of the incident signal as possible in the desired direction.Transmitting electromagnetic radiation with minimal losses due to dissipation, such as ohmic losses, or reflections in undesired directions, such as specular reflection, 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 conformity. In particular, the device should be able to conform to a curved surface and still function as desired. Based on this, the present invention aims to provide a device for the reflection and / or transmission of electromagnetic radiation that overcomes the described disadvantages.The present invention is based in particular on the objective of providing a device for the reflection and / or transmission of electromagnetic radiation which offers flexibility with regard to 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 with regard to its mounting not only to flat surfaces but also to be applied to curved surfaces with good surface fidelity. Description of the Invention: The objective is achieved 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.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 for the achievement of a desired radiation direction, minimizes side lobes (grating lobes), and maximizes directivity and gain in the main radiation direction (main lobe). The calculation, particularly in the case of periodicity, can be kept simple, and spatial aliasing can be avoided. Simultaneously, the coupling between the antenna elements can be managed.Each of the multiple 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. In particular, 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 illustrated in Figures 3a and 3b.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.It has been shown that the device according to the invention for the reflection and / or transmission of 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 at 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. It has been 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, particularly by an incident electromagnetic wave, which propagates through the phase-shift structure and thereby undergoes a phase shift. Depending on, for example,The phase shift can be adjusted by varying the length of the phase-shift structure. This allows for good matching to the free-space waveform, 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 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 and ohmic losses and, with appropriate dimensioning of the dielectric structures, enable true time delay, meaning the phase is accurately maintained across the entire device and not just at a maximum of 180° or 100°.360° phase shift is possible (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 has at different points on a curved surface.In particular, the phase-shift structures can simultaneously ensure that the device's height, i.e., the dimension perpendicular to the surface, remains low, especially by adjusting the phase shift per unit length through the selection of the dimensions of the phase-shift elements, particularly the dielectric ones. Compared to other RIS, which are mostly implemented on printed circuit boards, the described solution offers the advantage of avoiding ohmic losses and, through the use of dielectrics, being better suited for higher frequencies, thus also being suitable for the frequency ranges above 30 GHz considered with 6G, especially since dielectric losses decrease with increasing frequency, while ohmic losses in metal structures increase with the square root of the frequency.Furthermore, this solution overcomes the limitation to phase shifts between 0° and 180° and exhibits no significant change in amplitude when the phase changes (as is characteristic of RIS based on resonant elements with continuous phase variation, i.e., not just switching the phase between 0° and 180° as in so-called digital RIS). Moreover, in particular, not only a reflective but also a transmitting RIS is feasible, which can reduce path losses in various scenarios. 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, particularly without being as space-consumingly curved as a parabolic mirror, but rather extending flatly alongside the antenna. 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.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.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.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.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.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. The phase-shift structures, in particular the phase-shift elements, cause a phase shift that varies from location to location on the surface, in particular, for example, in the form of a gradient of the phase shift across the surface.For this purpose, the phase-shift structures, in particular 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 by L, where L is the length and L 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, in particular 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.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 mMore phase shift per unit length can be achieved. A notch in a resonant dielectric structure allows for suitable adjustment of the resonant frequency. 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 area on which the phase-shift structures are arranged in at least one, preferably in each, spatial direction. According to a further advantageous embodiment of the device according to the invention, the respective distance between each pair of adjacent phase-shift structures is between 20% and 80%, preferably approximately 50%, of the free-space wavelength corresponding to the predetermined lower cutoff frequency.According to a further advantageous embodiment of the device according to the invention, the at least one phase-shifting element comprises at least a plastic filled with ceramic particles and / or at least a ceramic dielectric. In particular, the at least one phase-shifting element consists of at least a plastic filled with ceramic particles and / or at least a ceramic dielectric. This makes it possible, in particular, to achieve a dielectric constant that is suitable for reducing the wavelength of the mode that forms on the dielectric structure, so that with a shortened wavelength λ. m = 2π / β mA correspondingly large phase shift per unit length can be achieved. 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 reflecting element for reflecting the electromagnetic radiation within the phase-shift structure; and / or - at least one transmitting element for transmitting the electromagnetic radiation within the phase-shift structure; and / or - at least one emitting element for emitting the electromagnetic radiation from the phase-shift structure. At least one receiving element can be provided for receiving the electromagnetic radiation into the phase-shift structure.The receiving element for receiving the electromagnetic radiation into the phase-shift structure 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. 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. For instance, the reflection element could be a metal plate.It is also conceivable that the at least one reflection element for reflecting the electromagnetic radiation within the phase-shift structure is a Frequency Selective Surface (FSS) element whose center frequency can be shifted, for example, by a liquid crystal plate or by diodes, so that switching between reflection and transmission is possible. The at least one 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. At least one transmission element can be provided for transmitting the electromagnetic radiation within the phase-shift structure. In particular, a transformation structure can be applied to the top side of at least one phase-shift element, e.g.,in the form of a hemisphere, particularly a dielectric one, which reduces specular reflection overall and / or the difference in reflection between the two polarization directions (with the transverse-electric (TE) or transverse-magnetic (TM) orientation). For a transmitting device, at least one transformation element and one phase-shifting element may be provided. At least one emitting element may be provided for radiating the electromagnetic radiation from the phase-shifting structure. The emitting element, in particular by its shape, determines the radiation characteristics, i.e., in particular 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 on the phase-shifting structure and the field distribution in the emitting element.The emitting element can, for example, be a spherical segment and the transformation element a cylinder. 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 orMagnetic field lines that run in a circular or star shape 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 every phase-shift element).Optionally, the multitude of phase-shift structures can be arranged on the surface of the device and configured in such a way that, for a given electromagnetic wave with an angle of incidence α, an electromagnetic wave incident on the device with an angle of reflection ^ is reflected and / or transmitted by reflection and / or transmission of electromagnetic radiation, wherein the angle of incidence α differs in magnitude from the angle of reflection ^, and wherein the angle of reflection ^ for a given angle of incidence α differs in magnitude from the angle of reflection ^ for electromagnetic radiation incident from an opposite side of a perpendicular with an equal angle of incidence α.This leads to the situation that electromagnetic radiation incident on the surface of the device from different directions with the same angle of incidence α can be reflected or transmitted at completely different angles of reflection ^. Consequently, the device exhibits different reflection and transmission properties for electromagnetic radiation incident on the surface from different spatial directions, even if it has the same angle of incidence α.Advantageously, it can also be provided that the plurality of phase-shift structures are arranged on the surface of the device and are designed in such a way that, with the device, for a given electromagnetic radiation with an angle of incidence α, which is greater than a critical angle in magnitude, the electromagnetic radiation with an angle of reflection ^ is transmitted, while the electromagnetic radiation incident on the surface from an opposite side of a perpendicular with the same angle of incidence α in magnitude is not transmitted.In this way, it can be achieved that for electromagnetic radiation incident on the surface of the device from different spatial directions with the same angle of incidence α, not only do different angles of reflection ^ result for the transmitted or reflected electromagnetic radiation, but that electromagnetic radiation incident on the surface from one direction with an angle of incidence α is transmitted at an angle of reflection ^, while electromagnetic radiation incident on the surface from an opposite spatial direction with the same angle of incidence α is generally not transmitted. The preferred embodiments described above in this description shall also be understood as being 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 figures The invention is explained in more detail below with reference to some drawings. They 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 the reflection of electromagnetic radiation at three exemplary phase-shift elements (111a-111c) of different lengths w, (w+Δw), and (w+2Δw); Fig.3b a schematic representation of the 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 staggered by Δw; Fig. 6 a schematic perspective view of an embodiment of a device according to the invention; Figs. 7-9 schematic perspective views of exemplary phase-shift structures; Figs. 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 line of sight (4a, 4b); Fig. 16a,b schematic representations of further exemplary scenarios in which one (Fig. 16a) or two (Fig. 16b) exemplary devices according to the invention are used by way of example; Fig. 17a-c schematic representations of further exemplary scenarios in which one (Fig. 17a, 17c) or two (Fig. 17b) exemplary devices according to the invention are used by way of example; Fig. 18 a schematic representation of incident and transmitted electromagnetic radiation during transmission of electromagnetic radiation through a device with six exemplary phase-shift elements (111a to 111f) of six exemplary phase-shift structures (110a to 110f); Fig.19 A schematic representation of the relationship between the angle of incidence and the angle of reflection of transmitted electromagnetic radiation for the embodiment schematically depicted in Fig. 18. Detailed description of some preferred embodiments Fig. 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, in particular mobile, terminal devices 1a-1e. While there is a line of sight (LOS) 5a, 5b, 5c to terminal devices 1b, 1d and 1e, there is no line of sight to terminal devices 1a and 1c from the perspective of the base station 2 due to obstacles 3a, 3b (see reference numerals 4a, 4b). Tree 3a and building 3b block the line of sight to receivers 1a and 1c (path 4a and 4b, respectively), while receivers 1b, 1d and 1e are accessible via paths 5c and 5b, respectively.5a Line of sight (LOS) exists. Fig. 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 respective height of each phase-shift element 111 (an example of a property related to a respective phase shift by a respective phase-shift element) depends on the position of the respective phase-shift element with respect to the surface 120.In this way, the phase shift of a particular portion of electromagnetic radiation incident on the device 100, caused by the device 100, depends on the location on the surface 120 where 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. Fig. 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-shift elements 111' arranged on a surface 120' and designed as circular cylindrical dielectric waveguides with different heights.Furthermore, in the device 100', the height of each phase-shift element 111' also depends on its position relative to the surface 120'. Consequently, the 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 that portion of the electromagnetic radiation strikes the device 100'. Unlike in the device 100, the height of the phase-shift elements 111' in the device 100' changes according to several gradients, particularly stepped gradients. Fig. 3a shows a schematic representation of the reflection of electromagnetic radiation 10 at three exemplary phase-shift elements 111a-111c. The incident electromagnetic radiation 10 is a plane electromagnetic wave.The phase-shift elements 111a-111c are designed as circular cylindrical dielectric waveguides with 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-shift 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. Fig. 3b shows a schematic representation of the reflection of electromagnetic radiation by 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 the corresponding incidence angle of the electromagnetic radiation (not shown in Fig. 3b). 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. Upon exiting the wave, they represent elementary waves with different phase angles, which 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.Figure 3b illustrates this. Figure 4 shows a schematic representation of a dispersion relation of an exemplary phase-shifting element, namely a circular cylindrical dielectric waveguide as shown in Figures 2a, 2b, 3a, and 3b. Line 21 shows a dispersion relation according to the equation f = βc / 2π, with the frequency f, the phase constant β, and the speed of light c. n in a dielectric medium, wherein c nThe equation c / n applies, where c is the speed of light in a vacuum and n is the refractive index of the dielectric medium. Furthermore, λ = c / f, where λ is the wavelength. Curve 22 shows a dispersion relation βm(f) of a circular cylindrical dielectric waveguide for a mode m. A phase shift φ achieved along a length L is given by φ = βm(f) L = 2π L / λm, where λm is the wavelength for mode m. Fig. 5 shows a schematic representation of the relationship between an angle of incidence (represented on the x-axis) and an angle of reflection (represented on the y-axis) of reflected electromagnetic radiation for exemplary phase shift elements.The family of curves 30-35 shows 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 difference Δw in the height of two adjacent waveguides between 0 and 0.5 mm. Fig. 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 phase-shift element 111 and a reflection element 113 (an example of the at least one reflection element for reflecting the electromagnetic radiation within the phase-shift structure).The phase-shifting elements 111 are configured as circular cylindrical dielectric waveguides with different heights. For example, the height of phase-shifting element 111a is greater than the height of phase-shifting element 111b. Consequently, the phase shift of a particular portion of electromagnetic radiation incident on the device 100, caused by the device 100, depends on the specific location on the surface 120 where the respective portion of the electromagnetic radiation strikes the device 100. Figures 7, 8, and 9 each show a schematic perspective view of an exemplary phase-shifting structure 110. The phase-shifting structure 110 shown in Figure 7 comprises a phase-shifting element 111, a receiving element 112, and a reflecting element 113.The receiving element 112 is designed 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 designed to reflect 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. The phase-shift structures 110a-c shown in Fig. 8 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. The phase-shift structure 110 shown in Fig. 9 comprises a phase-shift element 111, a receiving element 112, and a reflecting element 113.The receiving element 112 is hemispherical. Figures 10, 11, 12, 13, and 14 each show a schematic perspective view of exemplary phase-shift elements. For example, the phase-shift element 111 shown in Figure 10 has indentations 50a-d. Varying the diameter causes jumps in the characteristic impedance. The indentations 60a-c used in the phase-shift element 111 shown in Figure 11, within a resonant dielectric structure, enable, in particular, suitable adjustment of the resonant frequency. Figure 15 shows a schematic representation of an exemplary scenario in which several exemplary devices 100a-100e according to the invention are used. For example, devices 100a-100e are devices 100, 100' shown in Fig. 2a and / or Fig. 2b. Also Fig.Figure 16a shows an exemplary scenario in which an exemplary device 100 according to the invention is used. Figure 16b shows an exemplary scenario in which two exemplary devices 100 according to the invention are used. Figures 17a and 17c show further exemplary scenarios in which an exemplary device 100 according to the invention is used. Figure 17b shows a further exemplary scenario in which two exemplary devices 100 according to the invention are used. Figure 18 shows a schematic representation of the transmission of electromagnetic radiation through a device for which, for illustrative purposes only, six phase-shift structures 110a-110d, each with a phase-shift element 111a-111f, are arranged and shown on the surface 120.The phase-shift elements 111a-111f are designed as circular cylindrical dielectric waveguides with different heights. The height of each of the phase-shift elements 111a-111f, which are spaced apart from one another, changes uniformly, forming a height gradient that runs at an angle γ relative to the surface 120. The angle of incidence ^ of the electromagnetic radiation transmitted by the phase-shift elements 111a-111f differs from the corresponding angle of incidence α of the electromagnetic radiation. The angle of incidence α on an incident side of the surface 120, which is shown below the surface 120 in Fig. 18, and the angle of incidence ^ on a transmission side of the surface 120, which is shown above the surface 120 in Fig. 18, are each determined from and relative to a vertical.For the sake of simplicity, the following description of the relationship between angle of incidence α and angle of reflection ^ is simplified as follows: the angle of incidence α in a first quadrant, bounded by surface 120 and the vertical, is given a positive absolute value, while the angle of incidence α in a second quadrant, located on the side of the vertical opposite the first quadrant, is given a negative absolute value. Similarly, the angle of reflection ^ associated with a given angle of incidence α is also given with positive and negative absolute values, respectively, in the two quadrants separated by the vertical on the transmission side of surface 120. Figure 19 schematically illustrates various devices whose structural design is comparable to that shown in Figure 1.Figure 18 illustrates a relationship between the angle of incidence α and the angle of reflection ^ of the electromagnetic radiation incident on the device. For a device with a small gradient angle γ, which corresponds to a small height difference between adjacent phase-shift elements 111a-111f or a small phase shift Δφ between elementary waves emerging from the adjacent phase-shift elements 111a-111f, electromagnetic radiation incident almost parallel to the surface 120 with an angle of incidence α of almost 90° is emitted on the transmission side of the device with an angle of reflection ^ of 60°. The closer the angle of incidence α is to the vertical on the incidence side, the closer the angle of reflection ^ is to the vertical on the transmission side of the device.Electromagnetic radiation incident at an angle of incidence α = 5°, not yet perpendicular to the surface 120, is transmitted with an angle of reflection ^ = 0. For smaller angles of incidence α, the electromagnetic radiation is transmitted into the quadrant opposite the vertical on the transmission side, which is denoted by an angle of reflection ^ < 0. Thus, for an angle of incidence α = 0, electromagnetic radiation incident perpendicularly on the surface 120 is transmitted with an angle of reflection ^ < 0, or with an angle of reflection ^ = -5°. When the angle of incidence α of the electromagnetic radiation changes to the quadrant opposite the vertical and the angle of incidence α becomes < 0, the angle of reflection ^ of the transmitted electromagnetic radiation decreases accordingly. This is illustrated by curve 80 in Fig. 19.At a critical angle of incidence α, which is approximately α = -57° for curve 80, the angle of reflection ^ = -90°, so that the incident electromagnetic radiation is transmitted along surface 120 and is no longer emitted onto the transmission side of the device. At an angle of incidence α that is even smaller than the critical angle, no transmission whatsoever occurs onto the transmission side of the device. Therefore, the device exhibits qualitatively and significantly different transmission properties for incident electromagnetic radiation with an angle of incidence α > 0 compared to incident electromagnetic radiation with an angle of incidence α < 0.For an angle of incidence +α, which is greater in magnitude than the critical angle for the angle of incidence α, the incident electromagnetic radiation is transmitted into the transmission side of the surface 120, whereas electromagnetic radiation of the same magnitude, but incident from the other quadrant at an angle of incidence -α, experiences no transmission and instead undergoes total internal reflection. The shape of the curve 80 shown in Fig. 19 depends, among other things, on the design of the device with the phase-shift structures 110a-110f. Different transmission properties can be specified for different design configurations of the device. In Fig.Figure 19 shows two further curves 81 and 82 for the relationship between the angle of incidence α and the angle of reflection ^ of the electromagnetic radiation incident on the device, where curve 81 schematically and exemplarily shows the relationship for a device with phase-shift structures 110a-110f with a gradient angle γ twice as large as that of curve 80 and curve 82 shows the relationship for a device with phase-shift structures 110a-110f with a gradient angle γ three times as large compared to the device of curve 80.

[0002] Reference Symbol List 1 Mobile Device 2 Base Station 3 Obstacle 4 Interrupted Line of Sight 5 Uninterrupted Line of Sight 6 Light Sensor 7 Wall 8 Building 9 Vehicle 10 Incident Electromagnetic Radiation 10' Reflection of Incident Electromagnetic Radiation 10'' Reflected Electromagnetic Radiation 21 Straight Line 22 Curve 30-35 Curves 40 Axis of Symmetry 50 Constriction 51 Wide Section 60 Vertical Gap 70 Transverse Gap 80-82 Curves 100, 100' Device 110 Phase Shift Structure 111, 111' Phase Shift Element 112 Receiving Element 113 Reflecting Element 120, 120' Surface

Claims

PATENT CLAIMS 1. Device (100, 100') for the reflection and / or transmission of electromagnetic radiation, comprising a plurality of phase-shift structures (110) arranged on a surface (120, 120'); - wherein a respective distance between any two adjacent plurality of phase-shift structures (110) is less than twice a free-space wavelength corresponding to a predetermined lower cutoff frequency; - wherein each plurality of phase-shift structures (110) comprises at least one phase-shift element (111, 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, 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') at which the respective part of the reflected and / or; transmitted electromagnetic radiation strikes the device (100, 100'). 2.Device (100, 100') according to claim 1, wherein for each phase-shift structure (110) a phase shift of a predetermined electromagnetic wave caused by the at least one phase-shift element (111, 111') is specified such that the electromagnetic wave incident on the device (100, 100') is decomposed by the phase-shift structures (110) into elementary waves according to the Huygens principle, which propagate through the at least one phase-shift element (111, 111') and thereby experience different phase delays, so that the phase-shift structures (110) generate elementary waves with different phase positions upon exiting, which superimpose again according to the Huygens principle to form an electromagnetic wave with a wavefront whose wavefront is inclined in a predefinable direction according to the phase positions specified by the respective phase shift. 3.Device (100, 100') according to claim 2, wherein the phase shift structures (110) are arranged on the surface (120, 120') of the device (100, 100') and are designed such that, with the device (100, 100') for a predetermined electromagnetic wave, an electromagnetic wave incident on the device (100, 100') is reflected and / or transmitted in a predetermined direction by reflection and / or transmission of electromagnetic radiation.

4. Device (100, 100') according to claim 2 or 3, wherein the plurality of phase-shift structures (110) are arranged on the surface (120, 120') of the device (100, 100') and are configured such that, for a predetermined electromagnetic wave with an angle of incidence α, the device (100, 100') reflects and / or transmits an electromagnetic wave incident on the device (100, 100') with an angle of reflection ^ by means of reflection and / or transmission of electromagnetic radiation, wherein the angle of incidence α differs in magnitude from the angle of reflection ^, and wherein the angle of reflection ^ for a predetermined angle of incidence α differs in magnitude from the angle of reflection ^ for electromagnetic radiation incident from an opposite side of a perpendicular with an equal angle of incidence α. 5.Device (100, 100') according to claim 4, wherein the plurality of phase-shift structures (110) are arranged on the surface (120, 120') of the device (100, 100') and are designed such that the device (100, 100') transmits electromagnetic radiation with an angle of incidence α, the magnitude of which is greater than a critical angle, with a transmission of electromagnetic radiation with an angle of reflection ^, while electromagnetic radiation incident on the surface (120, 120') from an opposite side of a perpendicular with the same angle of incidence α is not transmitted.

6. Device (100, 100') according to any one of the preceding claims, 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.

7. Device (100, 100') according to any one of the preceding claims, wherein the phase-shift structures (110) are arranged at least partially regularly and / or at least partially irregularly on the surface (120, 120').

8. Device (100, 100') according to any one of the preceding claims, wherein a spatial region between the phase-shift structures (110) is filled with a dielectric.

9. Device (100, 100') according to any one of the preceding claims, wherein the at least one phase-shift element (111, 111') is configured as a dielectric waveguide and / or comprises at least one first dielectric resonator. 10.Device (100, 100') according to claim 9, 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.

11. Device (100, 100') according to any one of the preceding claims, wherein the at least one. Phase-shift element (111, 111') is at least partially, and at least substantially, spherical, cylindrical, and / or cuboidal.

12. Device (100, 100') according to one of the preceding claims, wherein the at least one property of the respective phase-shift element (111, 111') 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 (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').

13. 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. 14.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.

15. Device (100, 100') according to any one of the preceding claims, wherein the respective distance between each pair of 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.

16. Device (100, 100') according to any one of the preceding claims, wherein the at least one phase-shift element (111, 111') comprises or consists of at least one plastic filled with ceramic particles and / or at least one ceramic dielectric. 17.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 transmitting the electromagnetic radiation within the phase-shift structure (110); and / or - at least one emission element for emitting the electromagnetic radiation from the phase-shift structure (110).

18. 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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