An antenna system including a communication device, a dual-reflector antenna, and a gradient-index lens

Abstract

The present disclosure relates to an antenna system comprising: a communication device; a dual-reflector antenna; a gradient-index lens (GRIN lens). The communication device is configured to emit a primary planar electromagnetic wave to the GRIN lens, wherein the GRIN lens is configured to transform the emitted primary planar electromagnetic wave into a radiated Gaussian beam. The dual-reflector antenna is configured to transform the radiated Gaussian beam into a secondary planar electromagnetic wave and to emit the secondary planar electromagnetic wave to an outside of the antenna system. The communication device is configured to change a propagation direction of the emitted secondary planar electromagnetic wave by changing a propagation direction of the emitted primary planar electromagnetic wave.

Description

TECHNICAL FIELD

[0001] The present disclosure relates to an antenna system comprising a communication device and a dual-reflector antenna. BACKGROUND

[0002] The present disclosure relates to the field of antenna systems. Such antenna systems can comprise a communication device and a dual-reflector antenna for transmitting and / or receiving electromagnetic waves. A dual-reflector antenna can be an antenna comprising two reflectors for transmitting and / or receiving electromagnetic waves. SUMMARY

[0003] The inventors have made the following considerations:

[0004] Nowadays, challenging requirements for new generations of reflector antennas, with very high gain, very narrow beam and beam steering capability, have similar motivations for millimeter-wave, terahertz and optical wireless communications.

[0005] In millimeter-wave (MMW) at E-band and D-band, backhaul radio links over one kilometer distance can require antenna gains higher than 50 dBi to meet line-of-sight long distance link budget and withstand any atmospheric conditions; corresponding antennas with beamwidths narrower than half a degree can require careful installation. Moreover, such large diameter dish antennas are susceptible to high wind loads, and if installed on high towers or masts, their pointing can be affected by deflections, sway and vibrations of the supporting structure. Considering the typical case of an E-band backhaul antenna (operating frequency 71-86 GHz, dish diameter 2 ft (660 mm), i.e. about 170 wavelengths), and the equivalent case of a D-band antenna (operating frequency 130-175 GHz, nominal dish diameter 1 ft), both with gains higher than 50 dBi and beamwidths narrower than 0.4 degrees, a deflection of 1 degree of the supporting structure would mispoint the antenna, reducing the gain to 40 dBi.

[0006] In view of the above, the present disclosure aims to provide an antenna system that can cope with environmental influences that cause deflections, sway and vibrations of the antenna system. It is an object of the present disclosure to provide an antenna system that can cope with environmental influences on the antenna system to maintain sufficient antenna system gain.

[0007] These objects, as well as others that will become clear herein below, are achieved by the solution of the present disclosure described in the independent claims. Advantageous implementations are further defined in the dependent claims.

[0008] A first aspect of the present disclosure provides an antenna system, comprising: a communication device; a dual-reflector antenna; a gradient-index lens (GRIN lens). The communication device is configured to emit a primary planar electromagnetic wave to the GRIN lens, wherein the GRIN lens is configured to transform the emitted primary planar electromagnetic wave into a radiated Gaussian beam. The dual-reflector antenna is configured to transform the radiated Gaussian beam into a secondary planar electromagnetic wave and to emit the secondary planar electromagnetic wave to an outside of the antenna system. The communication device is configured to change a propagation direction of the emitted secondary planar electromagnetic wave by changing a propagation direction of the emitted primary planar electromagnetic wave.

[0009] In other words, the first aspect proposes to use a dual-reflector antenna and a GRIN lens in addition to a communication device for emitting a secondary planar electromagnetic wave, wherein the propagation direction of the emitted secondary planar electromagnetic wave can be changed by changing the propagation direction of the emitted primary planar electromagnetic wave.

[0010] That is, the communication device can be configured to perform beam steering of the secondary planar electromagnetic wave by changing the propagation direction of the primary planar electromagnetic wave. Changing the propagation direction of the primary planar electromagnetic wave can be referred to as beam steering of the primary planar electromagnetic wave. Changing the propagation direction of the secondary planar electromagnetic wave or performing beam steering of the secondary planar electromagnetic wave corresponds to or comprises pointing (re-pointing) an antenna beam that can be emitted by the antenna system (e.g., in the form of the secondary planar electromagnetic wave) to an outside of the antenna system. The term “beam scanning” can be used as a synonym for the term “beam steering”.

[0011] Thus, the antenna system is able to compensate for effects of yawing, rocking and / or vibrating (e.g., due to strong winds) on itself, e.g., to compensate for effects on a pointing of the antenna system. That is, the antenna system is configured to change the propagation direction of the secondary planar electromagnetic wave, thereby configured for re-pointing of the antenna system (i.e., of the antenna beam of the antenna system). Thus, effects of yawing, rocking and vibrating on a gain of the antenna system can be reduced or eliminated, such that the gain of the antenna system can be robust against environmental influences that cause yawing, rocking and / or vibrating of itself.

[0012] As mentioned above, the antenna system according to the first aspect enables full antenna beam control (e.g. beam control of the sub-planar electromagnetic waves within an angular sector (e.g. a limited angular sector)). For example, the angular sector can be ±1.5 degrees (±1.5°). This enables the antenna system to be used for wireless communication services. Additionally or alternatively, the antenna system can be used for satellite communication ground stations and / or radio telescope antennas (e.g. large radio telescope antennas). The antenna system is able to keep the gain loss and other radiation pattern degradation due to beam control at a level as low as possible. For example, the gain loss of the antenna system can be less than or equal to 1.5 dB (<1.5 dB). The antenna system can comply with ETSI class 4, i.e. can be an antenna system according to ETSI class 4 as described in the European norm document ETSI EN 302217-4.

[0013] The use of the dual-reflector antenna and the GRIN lens in combination enables changing the propagation direction of the emitted sub-planar electromagnetic waves, thereby pointing (re-pointing) the antenna beam that the antenna system can emit by changing the propagation direction of the emitted main-planar electromagnetic waves. Thus, the antenna system according to the first aspect does not need to move the dual-reflector antenna, the GRIN lens and / or the communication device (e.g. changing the position and / or orientation of the dual-reflector antenna, the GRIN lens and / or the communication device). Thus, no means for moving the mechanical components (e.g. one or more motors) of the antenna system are needed. In other words, the dual-reflector antenna, the GRIN lens and the communication device can remain fixed in the respective mounting positions (i.e. not move). This has the advantage that there is no wear or aging due to the movement of the mechanical components and thus no risk of malfunctioning of the antenna system due to wear or aging. Furthermore, the movement of the dual-reflector antenna, the GRIN lens and / or the communication device for re-pointing can limit the re-pointing speed of the antenna beam control. Thus, the antenna system according to the first aspect can enable a high re-pointing speed of the antenna beam control (i.e. changing the direction of the sub-planar electromagnetic waves). Thus, the antenna system can be used for a simple conical scan of the antenna beam, thereby enabling a high-speed tracking of a microwave beacon. Due to the fact that no means for moving the mechanical components of the antenna system are needed, the antenna system has a low complexity and low cost.

[0014] The antenna system according to the first aspect can provide an electronically controlled antenna beam (e.g. the main-planar electromagnetic waves and the sub-planar electromagnetic waves) control for anti-sway compensation. The antenna system can be used for an electronically controlled beam control by the GRIN lens over a beam scan angle range (e.g. a limited beam scan angle).

[0015] By providing an antenna system according to the first aspect, the present disclosure can provide a very high gain antenna hybrid assembly, in which a dual-reflector antenna can be matched with a communication device (e.g., an array feed) by a graded index (GRIN) lens.

[0016] The gradient-index lens (GRIN lens) is a lens that has a varying refractive index or a changeable refractive index inside the lens itself. That is, the GRIN lens can be characterized by a non-uniform refractive index. The GRIN lens has a distributed material density in order to achieve the varying refractive index inside the lens itself. The terms “index of refraction” and “refraction index” can be used as synonyms for the term “refractive index”. The term “graded index lens” can be used as a synonym for the term “gradient-index lens”, which can be abbreviated as the term “GRIN lens”. The Gaussian beam transformed from the launched plane-wave electromagnetic wave by the GRIN lens can be referred to as a “primary Gaussian beam”.

[0017] The primary plane electromagnetic wave and the secondary plane electromagnetic wave can be radio waves (such as microwaves, millimeter waves, or terahertz waves) or light waves. The primary plane electromagnetic wave and the secondary plane electromagnetic wave can be abbreviated as the terms “primary plane wave” and “secondary plane wave”, respectively. That is, the term “electromagnetic wave” can be abbreviated as the term “wave”.

[0018] Terahertz communication (THz communication) uses THz waves as electromagnetic waves, which can bridge the gap between millimeter wave communication and optical wireless communication. The electronic beam steering capability of a high-gain antenna at terahertz frequencies can be provided by the beam steering capability of the antenna system according to the first aspect, thereby achieving a substantial extension of the wireless communication distance. This can facilitate a large number of applications and meet the growing demand of users for higher data transmission rates.

[0019] Optical wireless communication uses light waves as electromagnetic waves, like free-space optical (FSO) links, can achieve higher data transmission rates, improve physical security, and avoid electromagnetic interference. The stability and quality of FSO links can depend to a large extent on atmospheric factors such as rain, fog, dust, and heat. Therefore, the electronic beam steering capability that can be provided by the beam steering capability of the antenna system according to the first aspect is an advantage for optical wireless communication.

[0020] The primary planar electromagnetic wave can be referred to as primary radiation or primary radiation beam, and the secondary planar electromagnetic wave can be referred to as secondary radiation or secondary radiation beam.

[0021] The dual-reflector antenna, the GRIN lens, and the communication device can be arranged to be immovable, i.e. mechanically fixed. For example, the GRIN lens and the communication device are arranged to be immovable for performing the beam steering of the secondary planar wave. In other words, the communication device can be used for changing the propagation direction of the secondary planar electromagnetic wave by changing the propagation direction of the primary planar wave without moving the GRIN lens. For example, the antenna system can be used for changing the propagation direction of the secondary planar electromagnetic wave by changing the propagation direction of the primary planar electromagnetic wave without moving the GRIN lens and optionally moving the communication device. The antenna system can be used for changing the propagation direction of the secondary planar electromagnetic wave by changing the propagation direction of the primary planar electromagnetic wave without moving the dual-reflector antenna, the GRIN lens, and the communication device.

[0022] The radiated Gaussian beam can be a spherical electromagnetic wave having an amplitude that varies along the wavefront according to a Gaussian distribution. The term "radiated Gaussian beam" can be abbreviated by the term "Gaussian beam".

[0023] The communication device of the antenna system according to the first aspect can be a transmitter. The terms "antenna feed line" and "feed line" can be used to refer to the communication device being a transmitter.

[0024] Optionally, the dual-reflector antenna can be configured to receive a sub-planar electromagnetic wave from outside the antenna system and transform the received sub-planar electromagnetic wave into a radiated Gaussian beam, wherein the GRIN lens can be configured to transform the radiated Gaussian beam into a main-planar electromagnetic wave. The communication device can be configured to receive the main-planar electromagnetic wave from the GRIN lens and change the propagation direction of the received sub-planar electromagnetic wave by changing the propagation direction of the received main-planar electromagnetic wave. In other words, optionally, the communication device of the antenna system according to the first aspect can be a transceiver that transmits and receives electromagnetic waves (e.g., the main-planar electromagnetic wave). The description regarding the transmitted main-planar wave and the transmitted sub-planar wave applies to the received main-planar wave and the received sub-planar wave, respectively. In case the communication device of the antenna system according to the first aspect is a transceiver, the description of the antenna system according to the second aspect of the present disclosure can apply to the antenna system according to the first aspect accordingly.

[0025] In an implementation form of the first aspect, the communication device is a multi-channel communication device configured to change the propagation direction of the transmitted main-planar electromagnetic wave by changing phases of two or more channels of the multi-channel communication device.

[0026] That is, the multi-channel communication device is configured to perform electronic beam steering of the sub-planar electromagnetic wave by changing the phases of the two or more channels of the multi-channel communication. Changing the phases of the two or more channels changes the propagation direction of the main-planar electromagnetic wave (i.e., performs beam steering of the main-planar electromagnetic wave). This changes the propagation direction of the sub-planar electromagnetic wave to provide beam steering of the sub-planar electromagnetic wave. The channels of the multi-channel communication device can be configured to be phase-controlled by electronic means.

[0027] The multi-channel communication device can comprise a plurality of channels, i.e., two or more channels. For example, the multi-channel communication device can comprise an array of 4 channels or 16 channels. These channels can be referred to as wireless channels.

[0028] Optionally, the communication device can be a multi-channel communication device configured to change the propagation direction of the received main-planar electromagnetic wave by changing phases of two or more channels of the multi-channel communication device. In other words, optionally, the multi-channel communication device of the antenna system according to the first aspect can be a transceiver that transmits and receives electromagnetic waves (e.g., the main-planar electromagnetic wave).

[0029] In an implementation form of the first aspect, the communication device comprises a single-channel communication device and a mirror. The single-channel communication device can be configured to emit the main-plane electromagnetic wave to the GRIN lens via the mirror, wherein the communication device can be configured to change the propagation direction of the emitted main-plane electromagnetic wave by rotating the mirror.

[0030] In other words, the single-channel communication device can be configured to emit the main-plane electromagnetic wave to the mirror; the mirror can be configured to reflect the emitted main-plane electromagnetic wave to the GRIN lens; and the communication device can be configured to change the propagation direction of the emitted main-plane electromagnetic wave by rotating the mirror. The mirror can be a planar mirror.

[0031] Optionally, the single-channel communication device can be configured to receive the main-plane electromagnetic wave from the GRIN lens via the mirror, wherein the communication device can be configured to change the propagation direction of the received main-plane electromagnetic wave by rotating the mirror. In other words, optionally, the communication device of the antenna system according to the first aspect (comprising a single-channel communication device and a mirror) can be a transceiver for transmitting and receiving electromagnetic waves (e.g., the main-plane electromagnetic wave).

[0032] In an implementation form of the first aspect, the dual-reflector antenna comprises a main reflector and a sub-reflector. The sub-reflector can be configured to reflect the radiated Gaussian beam from the GRIN lens to the main reflector. The main reflector can be configured to transform the radiated Gaussian beam into the emitted sub-plane electromagnetic wave by reflecting the radiated Gaussian beam.

[0033] The antenna system can be configured to have a gain greater than 47 dBi. To this end, the main reflector of the dual-antenna reflector can have an aperture expansion of the secondary plane wave greater than 120 wavelengths and amplify the primary plane electromagnetic wave emitted by the communication device. For example, the main reflector can be a main reflector of the secondary plane electromagnetic wave having a diameter greater than 120 wavelengths. For example, the antenna system can be an E-band microwave backhaul antenna configured to operate at frequencies between 71 GHz and 86 GHz. The main reflector of the dual- reflector antenna can have an expansion of 660 mm (e.g., be a reflector dish having a nominal diameter of 660 mm), which is approximately 170 wavelengths of the secondary plane wave, amplifying the primary plane electromagnetic wave emitted by the communication device. Alternatively, the antenna system can be a D-band antenna configured to operate at frequencies between 130 GHz and 175 GHz. The main reflector of the dual- reflector antenna can have an expansion of 360 mm (e.g., be a reflector dish having a nominal diameter of 360 mm). The antenna system can be configured to have a gain equal to or greater than 50 dBi. The antenna system can be configured to emit a beam having a beamwidth equal to or less than (i.e., narrower than) 0.4 degrees (0.4°) in the form of a secondary plane electromagnetic wave.

[0034] In the case where the communication device of the antenna system according to the first aspect is a transceiver, the main reflector can be configured to transform the received secondary plane electromagnetic wave into the radiated Gaussian beam by reflecting the received secondary plane electromagnetic wave to the sub-reflector. The sub-reflector can be configured to reflect the radiated Gaussian beam from the main reflector to the GRIN lens.

[0035] A second aspect of the present disclosure provides an antenna system comprising: a communication device; a dual-reflector antenna; a gradient-index lens (GRIN lens). The dual-reflector antenna is configured to receive a secondary plane electromagnetic wave from outside of the antenna system and transform the received secondary plane electromagnetic wave into a radiated Gaussian beam. The GRIN lens is configured to transform the radiated Gaussian beam into a primary plane electromagnetic wave. The communication device is configured to receive the primary plane electromagnetic wave from the GRIN lens and change a propagation direction of the received secondary plane electromagnetic wave by changing the propagation direction of the received primary plane electromagnetic wave.

[0036] The above description of the antenna system according to the first aspect can correspondingly apply to the antenna system of the second aspect. For example, the above description of the communication device, the GRIN lens and the dual-reflector antenna of the antenna system according to the first aspect can correspondingly apply to the communication device, the GRIN lens and the dual-reflector antenna of the antenna system according to the second aspect, respectively. The description about the transmitted primary planar wave and the transmitted secondary planar wave correspondingly apply to the received primary planar wave and the received secondary planar wave, respectively. The antenna system according to the second aspect can be the antenna system according to the first aspect. In this case, the communication device can be configured to transmit and receive primary planar electromagnetic waves. Thus, in this case, the communication device can be referred to as a transceiver.

[0037] The antenna system according to the second aspect and its implementation forms and optional features achieve the same advantages as the antenna system according to the first aspect and its corresponding implementation forms and optional features.

[0038] In an implementation form of the second aspect, the communication device is a multi-channel communication device configured to change the propagation direction of the received primary planar electromagnetic wave by changing phases of two or more channels of the multi-channel communication device. The channels of the multi-channel communication device can be configured to be phase-controlled by electronic means.

[0039] In an implementation form of the second aspect, the communication device comprises a single-channel communication device and a mirror. The single-channel communication device can be configured to receive the primary planar electromagnetic wave from the GRIN lens by the mirror, wherein the communication device can be configured to change the propagation direction of the received primary planar electromagnetic wave by rotating the mirror.

[0040] In other words, the mirror can be configured to reflect the primary planar electromagnetic wave from the GRIN lens to the single-channel communication device, which can be configured to receive the primary planar electromagnetic wave; the communication device can be configured to change the propagation direction of the received primary planar electromagnetic wave by rotating the mirror. The mirror can be a planar mirror.

[0041] In an implementation form of the second aspect, the dual-reflector antenna comprises a primary reflector and a sub-reflector. The primary reflector can be configured to transform the received secondary planar electromagnetic wave into the radiated Gaussian beam by reflecting the received secondary planar electromagnetic wave to the sub-reflector. The sub-reflector can be configured to reflect the radiated Gaussian beam from the primary reflector to the GRIN lens.

[0042] In an implementation form of the first aspect or the second aspect, the primary reflector and the sub-reflector are axisymmetric with respect to a common axis.

[0043] That is, the dual-reflector antenna can be an on-set dual-reflector antenna. The terms “axisymmetric dual-reflector antenna” and “on-set dual-reflector antenna” can be used as synonyms.

[0044] In an implementation form of the first aspect or the second aspect, the primary reflector is an axisymmetric parabolic reflector, and the sub-reflector can be an axisymmetric hyperbolic reflector or an axisymmetric elliptic reflector.

[0045] The terms “parabolic”, “elliptic” and “hyperbolic” can denote “quasi-parabolic”, “quasi-elliptic” and “quasi-hyperbolic”, respectively. The terms “elliptic” and “elliptical” can be used as synonyms. In other words, the dual-reflector antenna can be an on-set (i.e. axisymmetric) Gassegrain dual-reflector antenna, wherein the primary reflector is an axisymmetric parabolic reflector and the sub-reflector is an axisymmetric hyperbolic reflector. Alternatively, the dual-reflector antenna can be an on-set (i.e. axisymmetric) Gregorian dual-reflector antenna, wherein the primary reflector is an axisymmetric parabolic reflector and the sub-reflector is an axisymmetric elliptic reflector.

[0046] In an implementation form of the first aspect or the second aspect, the dual-reflector antenna is an off-set dual-reflector antenna. That is, the dual-reflector antenna can comprise an off-set primary reflector and an off-set sub-reflector.

[0047] In an implementation form of the first aspect or the second aspect, the dual-reflector antenna is a Gassegrain dual-reflector antenna or a Gregorian dual-reflector antenna.

[0048] The terms “Gassegrain antenna” and “Gregorian antenna” can be used to refer to a Gassegrain dual-reflector antenna and a Gregorian dual-reflector antenna, respectively.

[0049] The Gassegrain dual-reflector antenna can comprise a parabolic primary reflector and a hyperbolic sub-reflector. The Gregorian dual-reflector antenna can comprise a parabolic primary reflector and an elliptic sub-reflector.

[0050] In an implementation form of the first aspect or the second aspect, the dual-reflector antenna is an off-set Cassegrain antenna or an off-set Gregorian antenna. In other words, if the dual-reflector antenna is an off-set dual-reflector antenna, the dual-reflector antenna can be a Cassegrain antenna (i.e. an off-set Cassegrain antenna) or a Gregorian antenna (i.e. an off-set Gregorian antenna).

[0051] If the dual-reflector antenna is an off-set Cassegrain dual-reflector antenna, the primary reflector can be a parabolic off-set reflector, and the sub-reflector can be a hyperbolic off-set reflector. If the dual-reflector antenna is an off-set Gregorian dual-reflector antenna, the primary reflector can be a parabolic off-set reflector, and the sub-reflector can be an elliptic off-set reflector.

[0052] The dual-reflector antenna can be a dual-focal antenna (on-axis or off-axis) or a multi-focal antenna (on-axis or off-axis).

[0053] In an implementation form of the first aspect or the second aspect, the primary reflector and the sub-reflector are both parabolic cylindrical off-set reflectors. In other words, if the dual-reflector antenna is an off-set dual-reflector antenna, the primary reflector and the sub-reflector can both be parabolic cylindrical off-set reflectors. The terms “parabolic cylindrical (off-set) reflector” and “cylindrical parabolic (off-set) reflector” can be used as synonyms.

[0054] The above off-set dual-reflector antenna comprising two parabolic cylindrical reflectors can be used to transform the transmission of an axially symmetric Gaussian beam (e.g. the Gaussian beam generated or transformed by the emitted primary planar wave by the GRIN lens, which can be referred to as the primary Gaussian beam) into the transmission of an elliptical beam (which can be referred to as an elliptical secondary beam) in the form of a secondary planar wave, which can be emitted (e.g. radiated) outside the antenna system. That is, due to the dual-reflector antenna comprising a primary reflector and a sub-reflector, and each reflector being a parabolic cylindrical off-set reflector, the antenna beam that can be emitted by the antenna system can be an elliptical beam. In many antenna applications, it can be advantageous if a larger beam steering angle is desired in the vertical plane, while a smaller beam steering angle is desired in the horizontal plane. The antenna beam of an elliptical beam is wider in the vertical plane and narrower in the horizontal plane, as the degradation caused by beam steering can be balanced.

[0055] In an implementation form of the first or second aspect, the parabolic curvature of the main reflector and the parabolic curvature of the sub-reflector belong to mutually orthogonal different planes.

[0056] In an implementation form of the first or second aspect, the GRIN lens has an elliptical profile defining a plurality of regions of different material density.

[0057] That is, the GRIN lens can implement a distributed material density by defining a plurality of regions of different material density with an elliptical profile. The term “elliptical” can refer to “quasi-elliptical”. The plurality of regions of different material density defines a plurality of regions of different refractive index of the GRIN lens by defining the elliptical profile. That is, a region of different material density corresponds to a region of different refractive index. This enables to implement a varying or changeable refractive index within the GRIN lens. For example, the refractive index of the GRIN lens can be described with an (e.g. constant) elliptical profile.

[0058] In an implementation form of the first or second aspect, the GRIN lens comprises two surfaces, at least one of the two surfaces having a refractive index greater than the air refractive index.

[0059] Alternatively or additionally, at least one of the two surfaces can at least partially have an air refractive index. The shape of the two surfaces can be elliptical.

[0060] In an implementation form of the first or second aspect, the GRIN lens is configured to match a phase center of the Gaussian beam of radiation with a focal point of the dual-reflector antenna by a distributed material density.

[0061] In other words, the GRIN lens can be used to make the phase center of the radiated Gaussian beam equal to / coincide with / be in the vicinity of the focal point of the dual-reflector antenna in all operating conditions. The GRIN lens can be used to make the phase center of the radiated Gaussian beam almost coincide with the focal point of the dual-reflector antenna in all operating conditions. For example, when the main-plane electromagnetic wave propagates in parallel along the optical axis of the GRIN lens, then the phase center of the Gaussian beam matches (i.e. almost coincides) with the focal point of the dual-reflector antenna. Thus, the secondary-plane electromagnetic wave propagates along the boresight direction with respect to the radiating aperture of the primary reflector. However, if the main-plane electromagnetic wave propagates at an angle greater than zero (0°) along a direction deviating from the optical axis of the GRIN lens, then the phase center of the matched Gaussian beam is proportionally displaced from the focal point, according to the well-known proportional relationship, such that the propagation direction of the secondary-plane electromagnetic wave also deviates, wherein the proportional factor is defined as the beam deviation factor (BDF).

[0062] The phase center of the radiated Gaussian beam can be the focal point of the GRIN lens. The terms "focus" and "focal point" can be used as synonyms.

[0063] The GRIN lens can have multiple focal points (i.e. multiple phase centers of Gaussian beams), i.e. the GRIN lens is multi-focal. Each focal point of the multiple focal points corresponds to a different propagation direction of the main-plane electromagnetic wave.

[0064] The dual-reflector antenna can have a unique focal point. For example, such a dual-reflector antenna can be a dual-parabolic cylindrical antenna, a Cassegrain antenna or a Gregorian antenna. The dual-reflector antenna can be a dual-focal or multi-focal dual-reflector antenna. In this case, the dual-reflector antenna can have two or more focal points. The GRIN lens can be used to match its multiple focal points with the two or more focal points of the dual-reflector antenna by the distributed material density, wherein the dual-reflector antenna is a dual-focal or multi-focal dual-reflector antenna.

[0065] In an implementation form of the first aspect or the second aspect, the communication device is configured to use the GRIN lens to cause a displacement of the phase center of the Gaussian beam with respect to the focal point of the dual-reflector antenna by changing the propagation direction of the transmitted main-plane electromagnetic wave or the propagation direction of the received main-plane electromagnetic wave.

[0066] The greater the change in the direction of the primary electromagnetic wave, the greater the displacement of the phase center of the Gaussian beam relative to the focal point of the dual-reflector antenna. The greater the displacement of the phase center of the radiated Gaussian beam, the greater the change in the propagation direction of the secondary electromagnetic wave.

[0067] In one implementation of the first or second aspect, the communication device is used to cause a displacement of the phase center of the Gaussian beam, such that the greater the displacement of the phase center of the Gaussian beam relative to the focal point of the dual reflector antenna, the greater the change in the propagation direction of the transmitted or received subplane electromagnetic wave.

[0068] The greater the displacement of the phase center of the Gaussian beam relative to the focal point of the dual-reflector antenna, the greater the beam control angle of the subplane.

[0069] To implement the antenna system according to the first aspect of this disclosure, some or all of the implementations and optional features of the first and second aspects can be combined with each other. To implement the antenna system according to the second aspect of this disclosure, some or all of the implementations and optional features of the first and second aspects can be combined with each other.

[0070] All steps performed by the various entities described in this application and the functions performed by the various entities described are intended to indicate that each entity is suitable for or used to perform the corresponding steps and functions. Although the specific functions or steps performed by external entities are not reflected in the detailed description of the specific elements of the entities performing the specific steps or functions in the following description of specific embodiments, it will be apparent to those skilled in the art that these methods and functions can be implemented by corresponding software or hardware elements or any combination thereof. Attached Figure Description

[0071] The above aspects and implementations will be illustrated in the following specific embodiments, with reference to the accompanying drawings, in which:

[0072] Figure 1 Two examples of antenna systems according to embodiments of the present disclosure are illustrated schematically;

[0073] Figure 2 schematically shown Figure 1 Three different perspectives on the implementation of antenna systems;

[0074] Figure 3 schematically shown Figure 1 Examples of three different states of the antenna system of (A);

[0075] Figure 4Examples of two different states of the example of the antenna system are schematically illustrated;

[0076] Figure 5 Examples of two different states of the example of the antenna system are schematically illustrated Figure 1 Examples of two different states of the example of the antenna system are schematically illustrated

[0077] Figure 6 Examples of GRIN lenses of antenna systems according to embodiments of the present disclosure are schematically illustrated;

[0078] Figure 7 Examples of two different states of the example of the antenna system are schematically illustrated Figure 3 Examples of two different states of the example of the antenna system are schematically illustrated Figure 3 Examples of two different states of the example of the antenna system are schematically illustrated Figure 1 Examples of two different states of the example of the antenna system are schematically illustrated

[0079] Figure 8 Examples of two different states of the example of the antenna system are schematically illustrated Figure 9 Examples of two different states of the example of the antenna system are schematically illustrated

[0080] Figure 10 Examples of two different states of the example of the antenna system are schematically illustrated Figure 11 Examples of two different states of the example of the antenna system are schematically illustrated Figure 8 Examples of two different states of the example of the antenna system are schematically illustrated Figure 9 Examples of two different states of the example of the antenna system are schematically illustrated

[0081] Figure 12 Examples of two different states of the example of the antenna system are schematically illustrated Figure 13 Examples of two different states of the example of the antenna system are schematically illustrated Figure 8 Examples of two different states of the example of the antenna system are schematically illustrated Figure 9 Examples of two different states of the example of the antenna system are schematically illustrated

[0082] Figure 14 Examples of two different states of the example of the antenna system are schematically illustrated Figure 15 Examples of two different states of the example of the antenna system are schematically illustrated Figure 8 Examples of two different states of the example of the antenna system are schematically illustrated Figure 9 Examples of two different states of the example of the antenna system are schematically illustrated

[0083] Figure 16 A diagram showing one or more focal points of an example of a Cassegrain axi-symmetric dual-reflector antenna is shown;

[0084] Figure 17 A diagram showing a focal point of an example of a dielectric lens is shown.

[0085] In the drawings, corresponding elements are labeled with the same reference numerals. DETAILED DESCRIPTION

[0086] Figure 1 Examples of two examples of antenna systems according to embodiments of the present disclosure are schematically illustrated. Figure 1The antenna system of (A) is an example of the antenna system according to the first aspect and / or the second aspect of the present disclosure. Thus, the description of the antenna system according to the first aspect and the second aspect of the present disclosure can be applied accordingly to the antenna system of (A). Figure 1 The antenna system of (A).

[0087] Figure 1 The antenna system 1 of (A) comprises a communication device 2, a dual-reflector antenna 4, and a gradient-index lens (GRIN lens) 3. The GRIN lens 3 can have a proximal surface 3a and a distal surface 3b with respect to the communication device 2. The communication device 2 can be configured to emit a primary planar electromagnetic wave to the GRIN lens 3, wherein the GRIN lens 3 can be configured to transform the emitted primary planar electromagnetic wave into a radiated Gaussian light beam. The dual-reflector antenna 4 can be configured to transform the radiated Gaussian light beam into a secondary planar electromagnetic wave and to emit the secondary planar electromagnetic wave to the outside of the antenna system 1. The communication device 2 can be configured to change a propagation direction of the emitted secondary planar electromagnetic wave by changing a propagation direction of the emitted primary planar electromagnetic wave.

[0088] As shown in (A) of Figure 1 The dual-reflector antenna 4 can comprise a primary reflector 4b and a sub- reflector 4a. The sub-reflector 4a can be configured to reflect the radiated Gaussian light beam from the GRIN lens 3 to the primary reflector 4b. The primary reflector 4b can be configured to transform the radiated Gaussian light beam into the emitted secondary planar electromagnetic wave by reflecting the radiated Gaussian light beam.

[0089] As shown in (A) of Figure 1 The communication device 2 can be a multi-channel communication device 2a configured to change a propagation direction of the emitted primary planar electromagnetic wave by changing a phase of two or more channels of the multi-channel communication device 2a. When the communication device 2 is a multi-channel communication device 2a having multiple channels (e.g., wireless channels) (e.g., fed by a multi-channel radio), the phase shift associated with each channel (e.g., wireless channel) can be periodically aligned and calibrated. The multi-channel communication device 2a can enable precise self-alignment of channel phases to cope with phase offsets (due to repeatability of the technical process) and phase- unstable drifts (due to temperature and aging). Thus, this alignment capability can also be used to electronically control the change of the propagation direction of the primary planar wave, and thus electronically controlled beam steering can be performed by the antenna system 1.

[0090] Alternatively, as shown in (B) of Figure 1The communication device 2 can comprise a single-channel communication device 2b and a mirror 2c as shown in (B). Optionally, the mirror 2c is a flat mirror. The single-channel communication device 2b can be configured to emit a primary planar electromagnetic wave through the mirror 2c to the GRIN lens 3, wherein the communication device 2 can be configured to change the propagation direction of the emitted primary planar electromagnetic wave by rotating the mirror 2c. Thus, Figure 1 The antenna system 1 of (B) corresponds to Figure 1 The antenna system 1 of (A), wherein Figure 1 (B) shows an example of a possible implementation of the communication device 2. Figure 1 The description of the antenna system 1 of (A) applies accordingly to Figure 1 The antenna system 1 of (B).

[0091] Additionally or alternatively, Figure 1 The antenna system 1 of (A) or Figure 1 The dual-reflector antenna 4 of the antenna system 1 of (B) can be configured to receive a secondary planar electromagnetic wave from outside the antenna system 1 and to transform the received secondary planar electromagnetic wave into a radiated Gaussian light beam, wherein the GRIN lens 3 can be configured to transform the radiated Gaussian light beam into a primary planar electromagnetic wave. Furthermore, the communication device 2 can be configured to receive the primary planar electromagnetic wave from the GRIN lens 3 and to change the propagation direction of the received secondary planar electromagnetic wave by changing the propagation direction of the received primary planar electromagnetic wave.

[0092] For example, the primary reflector 4b can be configured to transform the received secondary planar electromagnetic wave into a radiated Gaussian light beam by reflecting the received secondary planar electromagnetic wave to the sub-reflector 4a. The sub-reflector 4a can be configured to reflect the radiated Gaussian light beam from the primary reflector 4b to the GRIN lens 3.

[0093] Figure 1 The communication device 2 of the antenna system of (A) can be a multi-channel communication device 2a configured to change the propagation direction of the received primary planar electromagnetic wave by changing the phase of two or more channels of the multi-channel communication device. The channels of the multi-channel communication device can be configured for phase control by electronic means.

[0094] Figure 1 The single-channel communication device 2b of the communication device 2 of the antenna system 1 of (B) can be configured to receive the primary planar electromagnetic wave from the GRIN lens 3 through the mirror 2c, wherein the communication device 2 can be configured to change the propagation direction of the received primary planar electromagnetic wave by rotating the mirror 2c.

[0095] As Figure 1As shown, the main reflector 4b and sub-reflector 4a of antenna system 1 can be axisymmetric with respect to a common axis. For example, the main reflector 4b can be an axisymmetric parabolic reflector, and the sub-reflector 4a can be an axisymmetric hyperboloid reflector, such as... Figure 2 As shown.

[0096] about Figure 1 For more information on antenna system 1, please refer to the description of the antenna system according to the first and second aspects.

[0097] Figure 2 schematically shown Figure 1 Three different perspectives on the implementation of antenna systems. Figure 2 (B) shows a front view of the distal surface 3b of the GRIN lens 3 of the antenna system 1; Figure 2 (C) shows a side view of antenna system 1; Figure 2 (A) shows when the antenna system is in Figure 2 (B) front view and Figure 2 The view when rotated between the side views of (C). As described above, according to Figure 2 Examples can be optionally implemented. Figure 1 (A) or Figure 1 The antenna system 1 of (B) is such that the main reflector 4b can be an axisymmetric parabolic reflector and the sub-reflector 4a can be an axisymmetric elliptic reflector. Figure 2 Antenna system 1 is an example of antenna system 1 that includes a Cassegrain antenna (used as a dual reflector antenna 4).

[0098] like Figure 2 As shown, the primary reflector 4b can be disposed between the GRIN lens 3 and the communication device 2. Therefore, the primary reflector 4b may include an opening 5 through which the communication device can transmit (e.g., transmit and / or receive) primary plane electromagnetic waves. Furthermore, as from... Figure 2 It can be deduced that the main reflector 4b and the sub-reflector 4a can be axisymmetric, sharing the same axis. For example, the dual-reflector antenna 4 (e.g., main reflector 4b and sub-reflector 4a), the GRIN lens 3, and the optional communication device 2 can be axisymmetric, sharing the same axis. They can be aligned along the same axis.

[0099] Figure 2 The Cassegrain configuration of the dual reflector antenna 4 is an axisymmetric focusing dual reflector antenna configuration. Figure 2The antenna system 1 can be used to perform a point beam with a gain of 50 dBi and beam control within ±1.5 degrees (±1.5°) in any plane via the common axis of symmetry of the main reflector 4b and the sub-reflector 4a. If the dual-reflector antenna 4 is axisymmetric (i.e., the main reflector 4b and the sub-reflector 4a are axisymmetric with respect to the same axis), the radiated Gaussian beam can be transformed by the dual-reflector antenna 4 into a point beam in the form of a subplane wave.

[0100] Figure 3 schematically shown Figure 1 Examples of three different states of the antenna system of (A). Figures 3 to 5 In the figure, rays representing primary plane electromagnetic waves are marked with the reference numeral "W1", and rays representing secondary plane electromagnetic waves are marked with the reference numeral "W2". Figures 3 to 5 The description assumes, by way of example only, that the communication device 2 of antenna system 1 is used to transmit a primary plane wave (which is used to transmit a secondary plane electromagnetic wave to the outside of antenna system 1), wherein the communication device is used to change the propagation direction of the transmitted secondary plane wave by changing the propagation direction of the transmitted primary plane wave. This description accordingly applies to cases where the communication device is additionally or alternatively used to receive a primary plane wave (which is used to receive a secondary plane wave from outside of antenna system 1).

[0101] exist Figure 3 In (A), an exemplary state is shown where communication device 2 does not perform beam control of the primary plane wave, and therefore does not perform beam control of the secondary plane wave. That is, the state in which communication device 2 transmits a targeting beam (without beam scanning) is shown. Figure 3 (B) and Figure 3 (C) shows the state in which communication device 2 performs beam control, that is, communication device 2 changes the direction of the subplane wave transmitted to the outside of antenna system 1 by changing the propagation direction of the transmitted main plane wave. Regarding Figure 3 The beamless state of (A), in Figure 3 In state (C), with Figure 3 Compared to state (B), greater beam control is performed. Since there is a GRIN lens 3 in addition to the dual reflector antenna 4, the communication device 2 can achieve beam control of the subplane wave by performing beam control of the main plane wave with no gain loss or with reduced gain loss. Figure 4 The example clearly illustrates this, showing an antenna system that includes a dielectric lens 6 (i.e., a lens with a uniform dielectric material) instead of a GRIN lens 3. The transmitted principal plane wave that hits or impacts the proximal surface 3a of the GRIN lens 3 can be characterized by a linear phase.

[0102] Figure 4The illustrations show two different states of an example antenna system. Figure 4 Antenna system 1 corresponds to Figure 3 Antenna system 1, wherein the GRIN lens 3 is replaced by a lens 6 having a uniform dielectric material. Therefore, Figures 1 to 3 The description can be applied accordingly. Figure 4 Antenna system.

[0103] like Figure 4 As shown in (A), without beam control, Figure 4 The functions and performance of antenna system 1 can correspond to Figure 3 The functions and performance of antenna system 1. That is to say, Figure 4 The state of (A) corresponds to Figure 3 The state of (A). However, as Figure 4 As shown in (B), when communication device 2 performs beam control of the main plane wave, it may cause [something related to] Figure 3 (B) and Figure 3 The (C) state has a greater gain loss compared to that state. That is, due to the use of dielectric lens 6 instead of GRIN lens 3, some waves or rays W3 provided by lens 6 will not strike or hit the dual reflector antenna 4, for example, sub-reflector 4a, such as Figure 4 As shown in (B). This leads to energy loss in the transmission of communication equipment, further resulting in... Figure 4 The gain loss of antenna system 1. The principal plane wave emitted by the medium lens 6 (i.e., the uniform lens) that hits or impacts the near-side surface (the surface of communication device 2) can be characterized by a constant phase.

[0104] Figure 5 schematically shown Figure 1 Examples of two different states of the antenna system (B). Figure 5 (A) shows Figure 1 Example of antenna system (B). Figure 5 The state of (B) corresponds to Figure 3 The state of (A), Figure 5 The state of (C) corresponds to Figure 3 The state of (B). Figure 3 The description accordingly applies to Figure 5 Antenna system 1.

[0105] exist Figure 5 In (B), an exemplary state is shown where the communication device 2 does not perform beam control of the primary plane wave, and therefore does not perform beam control of the secondary plane wave. That is, the state in which the communication device 2 is used to transmit a targeting beam (without beam scanning) is shown. For this purpose, for example, the reflector 2c of the communication device 2 can be set at a 45-degree (45°) angle with the optical axis of the GRIN lens.Figure 5 (C) shows a state in which the communication device 2 performs beam control, i.e. the communication device 2 changes the direction of the secondary plane wave transmitted to the outside of the antenna system 1 by changing the direction of the primary plane wave transmitted. To this end, Figure 1 The communication device 2 of the antenna system 1 of (B) is configured to change the propagation direction of the transmitted primary plane wave by rotating the mirror 2c. That is, the mirror 2c can be rotated (e.g. slightly rotated) with respect to Figure 5 The mirror 2c shown in (B) can be rotated (e.g. slightly rotated) with respect to the state of the mirror 2c shown in (A). Due to the presence of the GRIN lens 3 in addition to the dual-reflector antenna 4, the communication device 2 can achieve beam control of the secondary plane wave by beam control of the primary plane wave with no gain loss or reduced gain loss.

[0106] Figure 6 An example of a GRIN lens of an antenna system according to an embodiment of the present disclosure is schematically shown.

[0107] Figure 6 (A) shows an example of one implementation of a GRIN lens, e.g. for Figure 1 The GRIN lens 3 of the antenna system of (B) and / or Figure 8 and Figure 9 The GRIN lens 3 of the antenna system of (B). When the GRIN lens 3 is arranged in the antenna system 1, the GRIN lens 3 has a proximal surface and a distal surface with respect to the communication device 2 of the antenna system 1, which are marked by reference sign “3a” and reference sign “3b”, respectively. That is, the GRIN lens 3 can comprise two surfaces, surface 3a and surface 3b. At least one of the two surfaces 3a and 3b can have a refractive index which is larger than the refractive index of air. Alternatively or additionally, at least one of the two surfaces 3a and 3b can at least partially have the refractive index of air. The shape of the surfaces 3a and 3b can be elliptical. As Figure 6 As shown in (A), the GRIN lens 3 can optionally be provided with a plurality of holes 3c at its surface. This can provide for a refractive index at the surface of the GRIN lens 3.

[0108] As mentioned above, the GRIN lens 3 is a lens which has a varying refractive index or a changeable refractive index inside the lens. That is, the GRIN lens 3 can be characterized by a non-uniform refractive index. The GRIN lens 3 has a distributed material density in order to achieve a varying refractive index inside the lens.

[0109] For example, the GRIN lens 3 has a plurality of elliptical profiles defining regions of different material density. That is, the GRIN lens 3 can implement a distributed material density by defining regions of different material density by a plurality of elliptical profiles. The term “elliptical” can refer to “quasi-elliptical”. The plurality of elliptical profiles define regions of different refractive index of the GRIN lens by defining regions of different material density. That is, the regions of different material density correspond to regions of different refractive index. This enables to implement a varying refractive index or a changeable refractive index within said GRIN lens. This is in particular the case for a quasi-elliptical profile of the GRIN lens 3. Figure 6 is exemplarily shown in (B) of Fig. 3. Figure 6 (B) of Fig. 3 exemplarily shows different profiles 3d (e.g. elliptical profiles) defining regions of different refractive index. Examples of values of the different refractive index are shown in (B) of Fig. 3. Figure 6 of (B) of Fig. 3, which applies to the entire respective profile 3d, i.e. also to the Figure 6 of (B) of Fig. 3, which applies to the entire respective profile 3d, i.e. also to theFor example, at the middle of the GRIN lens 3, the refractive index of the GRIN lens 3 can be greater than at the sides of the GRIN lens 3. For example, the refractive index can decrease from 1.4 to 1.2, as shown in (B) of Fig. 3. Figure 6

[0110] When the GRIN lens 3 is arranged in a fixed position in the antenna system between the communication device 2 and the dual reflector antenna 4 (e.g. characterized by its quasi-elliptical profile of refractive index), it is made possible to achieve an optimum of the focal point displacement for each direction of propagation of the main plane wave. To this end, the main plane wave impinging on the proximal surface 3a of the GRIN lens 3 can be characterized by a suitable phase wave front, which is linear or quasi-linear.

[0111] The capability of transforming the phase wave front (e.g. quasi-linear phase) of the emitted main plane wave into a displacement of the focal point of a Gaussian beam (main Gaussian beam) corresponding to a change of the direction of propagation of the emitted main plane wave can be achieved by the quasi-elliptical profile of the different refractive index of the GRIN lens 3 and / or the respective shaped surfaces (proximal and distal surfaces).

[0112] Figure 7 An example of a chart showing the relationship between the antenna radiation pattern gain and the beam steering angle for the two states of the antenna system of (A) of Fig. 4 and (B) of Fig. 4 is shown in (C) of Fig. 4. Figure 3 Figure 3 Figure 1 An example of a chart showing the relationship between the antenna radiation pattern gain and the beam steering angle for the two states of the antenna system of (A) of Fig. 4 and (B) of Fig. 4 is shown in (C) of Fig. 4.

[0113] For the example of (A) of Fig. 5, it is assumed that Figure 7 Figure 1 ​​​The dual-reflector antenna 4 of the antenna system in (A) is a 360mm Cassegrain antenna, optimized for a frequency of 150 GHz for the electromagnetic waves to be transmitted and / or received. Furthermore, Figure 7 The description, by way of example, assumes that the communication device 2 of the antenna system 1 is used to transmit a primary plane wave (which is used to transmit a secondary plane electromagnetic wave to the outside of the antenna system 1), wherein the communication device 2 is used to change the propagation direction of the transmitted secondary plane wave by changing the propagation direction of the transmitted primary plane wave. This description accordingly applies to cases where the communication device 2 is additionally or alternatively used to receive a primary plane wave (which is used to receive a secondary plane wave from the outside of the antenna system 1).

[0114] exist Figure 7 In the diagram, curve C1 shows that... Figure 3 In state (A), that is, without beam control (i.e., the antenna radiation is within the aiming area), the antenna pattern of the antenna system is shown. In this case, the angle of the transmitted principal plane wave is 0 degrees (0°). That is, the propagation direction of the transmitted principal plane wave does not change. Curve C2 shows the antenna pattern in... Figure 3 In state (B), that is, when beam control is being performed, the antenna pattern of the antenna system. For example, as... Figure 7 As shown, without beam control, the controlled beam may have an angle of 1.6 degrees (1.6°) relative to the main beam. In other words, it can be assumed that the communication device changes the propagation direction of the transmitted main plane wave so that, without beam control, the changed propagation direction deviates from the propagation direction of the transmitted main plane wave by an angle of 1.6°. Figure 7 As shown, in both cases—no beam control and beam control of the main plane wave at 1.6°—the peak gain of the antenna pattern may exceed 52 dBi. That is, the reduction in antenna radiation gain due to beam control is small and can be ignored. Furthermore, Figure 7 Curve C3 in the diagram shows the mask pattern for an ETSI Category 4 antenna system. Therefore, for both cases with and without beam control (e.g., 1.6°), Figure 1 Antenna system 1 of (A) can meet the requirements of ETSI Category 4.

[0115] Figure 8 and Figure 9 Two different perspectives are schematically shown as examples of antenna systems according to embodiments of the present disclosure.

[0116] Figure 8 and Figure 9The antenna system of Figure 8 and / or the second aspect of the present disclosure. Thus, the description of the antenna system according to the first aspect and the second aspect of the present disclosure can apply accordingly to the antenna system of Figure 9 and Figure 8 . Figure 9 The antenna system of Figure 1 corresponds to the antenna system of (A) wherein the Figure 1 axial symmetric dual-reflector antenna of the antenna system of (A) is compared to Figure 8 and Figure 9 The dual-reflector antenna implementation of the antenna system of Figures 1 to 6 is different. Thus, the description of Figure 8 and Figure 9 applies accordingly to the antenna system of Figure 8 and Figure 9 and is mainly described in the following for the dual-reflector antenna of the antenna system of

[0117] As shown in Figure 8 and Figure 9 , both the primary reflector 4b and the sub-reflector 4a of the dual-reflector antenna 4 can be parabolic cylindrical defocussing reflectors. Optionally, the parabolic curvature of the primary reflector 4b and the parabolic curvature of the sub-reflector 4a belong to different planes (not shown in Figure 8 and Figure 9 ) which are orthogonal to each other. Thus, the dual-reflector antenna 4 of the antenna system 1 can have a dual-defocussing configuration (i.e. it can be a dual-defocussing antenna) as shown in Figure 8 and Figure 9 . This is a different type of dual-reflector antenna 4 compared to the dual-reflector antenna 4 of the antenna system of Figure 2 , i.e. a Cassegrain axial symmetric antenna. The dual-defocussing configuration (as exemplarily shown in Figure 2 and Figure 8 and Figure 9 ) can achieve a wider beam steering angle or higher efficiency and antenna gain compared to the Cassegrain axial symmetric dual-reflector antenna (as exemplarily shown in

[0118] According to the examples of Figure 8 and Figure 9 , the primary reflector 4b and the sub-reflector 4a are not axial symmetric. This can achieve a two-dimensional beam steering with an angular sector of ±10 degrees (±10°) in the elevation angle (vertical plane) and ±2 degrees (±2°) in the azimuth angle (horizontal plane). This angular sector can be enlarged compared to the case where a dual-reflector antenna 4 with a primary reflector 4b and a sub-reflector 4a which are axial symmetric with respect to a common axis is used (e.g. a Cassegrain antenna is used). If the dual-reflector antenna 4 is not axial symmetric, as shown in Figure 8 and Figure 9The illustrated dual-focal configuration, the radiated Gaussian beam (the primary Gaussian beam) is still axisymmetric and can be transformed by the parabolic cylindrical configuration of the primary reflector 4b and the sub-reflector 4a of the dual-reflector antenna 4 into an elliptical beam in the form of a transmitted secondary planar wave. The dual-focal dual-reflector antenna 4 (i.e. the dual-reflector antenna having a dual-focal configuration) comprising the parabolic cylindrical primary reflector 4b and the parabolic cylindrical sub-reflector 4a can be referred to as a dual-reflector antenna having a dual-parabolic cylindrical reflector configuration.

[0119] Figure 10 and Figure 11 schematically illustrates Figure 8 and Figure 9 two different perspectives of an example of an implementation of the antenna system of Figure 8 and Figure 9 the description of Figure 10 and Figure 11 the antenna system applies accordingly. As shown in Figure 10 and Figure 11 the primary reflector 4b of the dual-reflector antenna 4 can be a parabolic cylindrical focal primary reflector and the sub-reflector 4a of the dual-reflector antenna 4 can be a parabolic cylindrical focal sub-reflector. In this case, the dual-reflector antenna 4 can be an elliptical beam antenna, wherein the control angular sector of the antenna beam is rectangular. This example of a dual-parabolic cylindrical reflector configuration of the dual-reflector antenna 4 enables the antenna system 1 to implement a beam control, e.g. a height angle (vertical plane) of ±10° and an azimuth angle (horizontal plane) of ±2°. To this end, the GRIN lens 3 of the antenna system 1 can be suitably designed to manage the two-dimensional displacement of the focal point according to the beam control requirements (e.g. ETSI class 4 requirements). The elliptical beam antenna 4 can be designed so that the focal point displacement describes a trajectory characterized by a rectangular edge. The shape of the GRIN lens surfaces (distal surface and proximal surface) can be elliptical. Moreover, the constant profile of the different refractive indices of the GRIN lens 3 can be elliptical or elliptical-shaped.

[0120] Figure 12 and Figure 13 schematically illustrates Figure 8 and Figure 9 two different perspectives of an example of an implementation of the antenna system of Figure 8 and Figure 9 the description of Figure 12 and Figure 13 the antenna system applies accordingly. As shown in Figure 12 and Figure 13 the primary reflector 4b of the dual-reflector antenna 4 can be a parabolic cylindrical focal primary reflector and the sub-reflector 4a of the dual-reflector antenna 4 can be a parabolic cylindrical focal sub-reflector. In this case, the dual-reflector antenna 4 can be an elliptical beam antenna, wherein the control angular sector of the antenna beam is rectangular. This example of a dual-parabolic cylindrical reflector configuration of the dual-reflector antenna 4 enables the antenna system 1 to implement a beam control, e.g. a height angle (vertical plane) of ±10° and an azimuth angle (horizontal plane) of ±2°. To this end, the GRIN lens 3 of the antenna system 1 can be suitably designed to manage the two-dimensional displacement of the focal point according to the beam control requirements (e.g. ETSI class 4 requirements). The elliptical beam antenna 4 can be designed so that the focal point displacement describes a trajectory characterized by a rectangular edge. The shape of the GRIN lens surfaces (distal surface and proximal surface) can be elliptical. Moreover, the constant profile of the different refractive indices of the GRIN lens 3 can be elliptical or elliptical-shaped. Figure 12 Figure 13 ​In the present case, the communication device 2 is exemplarily shown as a multi-channel communication device comprising an array of 16 channels. This is just an example. Thus, the communication device 2 can be a different communication device (e.g. a communication device comprising a single-channel communication device and a mirror) or can comprise a different number of channels.

[0121] Figure 14 and Figure 15 respectively show examples of diagrams of the relationship between the antenna radiation pattern gain and the beam steering angle for two states of the antenna system of Figure 8 and Figure 9 .

[0122] For the examples of Figure 14 and Figure 15 it is assumed that the dual-reflector antenna 4 of the antenna system of Figure 8 and Figure 9 is a dual-cylindrical antenna (e.g. a defocussing antenna configuration) optimized at a frequency of 150 GHz of the electromagnetic waves to be transmitted and / or received. Further, Figure 14 and Figure 15 the description of the antenna system 1 assumes by way of example that the communication device 2 is used for transmitting a primary plane wave (which is used for transmitting a secondary plane electromagnetic wave to the outside of the antenna system 1), wherein the communication device is used for changing the propagation direction of the transmitted secondary plane wave by changing the propagation direction of the transmitted primary plane wave. The description accordingly applies to the case that the communication device 2 is additionally or alternatively used for receiving a primary plane wave (which is used for receiving a secondary plane wave from the outside of the antenna system 1).

[0123] Figure 14 shows the antenna pattern for the elevation angle (vertical plane) angular sector, Figure 15 shows the antenna pattern for the azimuth angle (horizontal plane) angular sector.

[0124] In Figure 14 and Figure 15 the curve C1 shows the antenna pattern of the antenna system without performing beam steering (i.e. the antenna radiation is in the boresight). In this case, the angle of the primary plane wave transmitted in the vertical plane (see Figure 14 ) as well as in the horizontal plane (see Figure 15 ) is 0 degrees (0°). That is, the propagation direction of the transmitted primary plane wave is not changed. In Figure 14 and Figure 15 the curve C2 shows the antenna pattern of the antenna system with performing beam steering. For example, as Figure 14As shown, in the vertical plane, without beam control, the controlled beam may have an angle of 10 degrees (10°) relative to the main plane wave. In other words, it can be assumed that the communication device changes the propagation direction of the transmitted main plane wave in the vertical plane such that, without beam control, the changed propagation direction deviates from the propagation direction of the transmitted main plane wave by an angle of 10°. For example, as... Figure 15 As shown, in the horizontal plane, without beam control, the controlled beam may have an angle of 2.3 degrees (2.3°) relative to the beam. In other words, it can be assumed that the communication device changes the propagation direction of the transmitted main plane wave in the horizontal plane such that, without beam control, the changed propagation direction deviates from the propagation direction of the transmitted main plane wave by an angle of 2.3°.

[0125] like Figure 14 As shown, for the two cases—no beam control in the vertical plane and beam control of the subplane wave in the vertical plane at 10°—the peak gain of the antenna pattern may be greater than 48.5 dBi. That is, the reduction in antenna radiation gain due to beam control in the vertical plane is small and can be ignored. Figure 15 As shown, for the two cases—no beam control in the horizontal plane and beam control of the subplane wave in the horizontal plane at 2.3°—the peak gain of the antenna pattern may be greater than 50 dBi. In other words, the reduction in antenna radiation gain due to beam control in the horizontal plane is relatively small and can be ignored.

[0126] exist Figure 8 and Figure 9 In the diagram, curve C3 shows the mask pattern for an ETSI Category 4 antenna system. Therefore, for both cases, Figure 1 and Figure 1 The antenna system 1 can meet the ETSI Category 4 requirements, namely, no beam control and beam control (e.g., 10°) in the vertical plane and no beam control and beam control (e.g., 2.3°) in the horizontal plane.

[0127] The following description is based on Figure 1 (A) and Figure 16 Example of a design method for implementing antenna system 1 (B). This design method enables the step-by-step configuration of the entire antenna system. This design method can be part of or as part of a computer-aided program.

[0128] In a first step (step 1) of the design method, the dual-reflector antenna 4 comprising the sub-reflector 4a and the main reflector 4b can be designed so that the desired low control loss and low optical aberration effects are properly performed in the desired angular interval of the beam steering. For example, it can be desired that the control loss is as low as 1.5 dB, and it can be desired that the optical aberration effects do not impair the ETSI class 4 specification regarding the antenna radiation pattern envelope, while the angular interval desired for the beam steering can be between -1.5° and +1.5°, i.e. [-1.5°, +1.5°].

[0129] In a second step (step 2) of the design method, the communication device 2 can be designed in association with an auxiliary lens having a uniform dielectric material, e.g. a planar hyperboloidal converging lens made of a uniform dielectric material. To this end, it can be assumed that the communication device 2 is a transmitter for providing or emitting main planar electromagnetic waves, e.g. an array feed.

[0130] In a third step (step 3) of the design method, the auxiliary lens can be replaced by a properly designed GRIN lens, i.e. the GRIN lens 3. It can be a feature of the GRIN lens that its refractive index profile is elliptical (quasi-elliptical), or it can be a feature of the GRIN lens that its surface shape is properly shaped.

[0131] According to the first step (step 1) of the design method, a computer-aided procedure can be established to optimize the dual-reflector antenna 4 of the antenna system 1. It can be assumed that the main reflector 4b of the dual-antenna reflector 4 is a parabolic (e.g. quasi-parabolic) main reflector dish, and that the sub-reflector 4a is a hyperbolic (e.g. quasi-hyperbolic) sub-reflector. Such reflectors can be designed as axially symmetric rotational surfaces in order to reduce the complexity and cost of manufacturing as much as possible.

[0132] Furthermore, it can be assumed that the antenna system is optimized at a frequency of 150 GHz of the electromagnetic waves to be emitted and / or received, so that the antenna system can comply with the ETSI class 4 specification. In a first sub-step (step 1.1) of the first step (step 1), the performance of the preliminary dual-reflector antenna mechanical configuration can be evaluated. In a second sub-step (step 1.2) of the first step (step 1), the illumination attenuation at the edge of the sub-reflector can be gradually reduced to comply with the ETSI class 4 specification. In a third sub-step (step 1.3) of the first step (step 1), the final antenna assembly of the dual-reflector antenna can be evaluated in terms of the mechanical configuration and the radiation performance of the dual-reflector antenna. In a fourth sub-step (step 1.4) of the first step (step 1), it can be assumed that the constant product of the antenna gain and the maximum beam steering angle (antenna gain x maximum beam steering angle) of the antenna system is 150000 = 50 dBi antenna gain x 1.5° maximum beam steering angle. If a larger beam steering is required, a multi-focal dual-reflector antenna with 45 dBi gain x 5° maximum beam steering angle can be assumed or implemented.

[0133] The mechanical configuration of the dual-reflector antenna 4 of the antenna system can be completed during the first step (step 1) of the design method. In other words, the surfaces of the primary reflector 4b and the sub-reflector 4a of the dual-reflector antenna 4 can be designed together with the position of the focal point, including also its optimal displacement, to achieve the desired control of the antenna beam (e.g., sub-planar electromagnetic wave) and the re- pointing angle of the Gaussian beam towards the sub-reflector 4a.

[0134] The ray beam (e.g., Gaussian beam) hitting the sub-reflector 4a starts from a focal point whose position is optimized to have as low as possible gain loss (e.g., < 1.5 dB) due to beam control and to minimize the optical aberrations that could compromise the ETSI-compliant (e.g., class 4) radiation pattern envelope. However, when the antenna radiates in the boresight (i.e., without beam control), the ray beam will start from a different focal point located on the symmetry axis of the dual-reflector antenna.

[0135] With regard to the emission of electromagnetic waves by the antenna system (e.g., the antenna system of Figure 17 , the focal point displacement for optimal antenna beam control can be obtained by a mechanical rotation of the feed assembly, e.g., made of the feed array (i.e., the transmitter for the electromagnetic waves) and the associated lens. Thus, for each desired beam direction, there can be an optimal focal point displacement.

[0136] After the configuration of the dual-reflector antenna during the first step (step 1) of the design method, further design steps (step 2 and step 3) can be performed. The second step (step 2) and the third step (step 3) of the design method are described below in connection with Figure 16 and Figure 17 . Figure 16 a diagram showing one or more focal points of an example of a Cassegrain axisymmetric dual-reflector antenna; Figure 16 a diagram showing a focal point of an example of a dielectric lens.

[0137] Without summarizing the second step (step 2) and the third step (step 3) of the design method, and just to simplify the description, the exemplary description of these steps considers the one-dimensional case of a Cassegrain dual-reflector antenna, e.g., a parabolic primary reflector 4b with a hyperbolic sub-reflector 4a (elliptical sub-reflector) in a focal configuration, both characterized by an axisymmetry as shown in Figure 17 The same considerations apply to many other dual-reflector antenna configurations, including off-focal Cassegrain or Gregorian, bifocal or multifocal (both focal and off-focal). That is, the following description is not limited to the case of a dual-reflector antenna being a Cassegrain dual-reflector antenna, and thus can be adapted accordingly to other types of dual-reflector antennas.

[0138] InFigure 17 In this context, let 2a be the length of the parabolic reflector aperture, and x be its abscissa. Furthermore, let u = 2π / λsin(θ) be the abscissa on the wavenumber axis, where θ is the angle of the side-emitting direction and λ is the operating wavelength. The radiation pattern G(u) and the aperture illumination function f(x) are related through the following Fourier transform:

[0139]

[0140] In addition, the equivalent focal point of the Cassegrain dual-reflector antenna is as follows:

[0141]

[0142] In the above equation, term "F" represents the focal point of the parabolic reflector, and term "e" represents the ellipticity of the sub-reflector. The feed angle θa of this Cassegrain optic can be calculated using the following relationship:

[0143]

[0144] Similarly, one-dimensional cases can be considered for auxiliary converging lenses made of homogeneous dielectric materials (e.g., planar hyperboloid converging lenses made of homogeneous dielectric materials), such as... ​ As shown. Such an auxiliary lens can be called a dielectric lens.

[0145] exist ​ In this context, let 2r be the diameter of the lens aperture, and x' be its abscissa. Furthermore, let u' = 2π / λsin(θ') be the abscissa on the wavenumber axis, where θ' is the angle of the side-emitting direction, and λ is the operating wavelength. The radiation pattern G(u') and the aperture illumination function f(x') are related through the following Fourier transform:

[0146]

[0147] The feed angle θr of the converging lens can be related to the optical focal length, as shown below:

[0148] sin(θr)=r / F L

[0149] Next, the aforementioned auxiliary lens can be combined "back-to-back" with the aforementioned Cassegrain dual-reflector antenna, such that the relevant focal points are matched at the same point, and the auxiliary lens focuses its illumination f(x'), while the Cassegrain dual-reflector antenna focuses its illumination function f(x). This can provide a hybrid optical system formed by assembling or placing dual-reflector optics (e.g., dual-reflector antenna) and lens optics (e.g., auxiliary lens) together. The latter can be appropriately matched such that a magnifying glass can be obtained that transforms illumination f(x') into illumination f(x), with a magnification factor μ expressed by the following equation:

[0150] Assuming this magnifying glass as a first approximation, the following linear transformation is performed:

[0151] f(x) = μf(x’),

[0152] Finally, the antenna radiation pattern becomes:

[0153]

[0154] This antenna pattern is the Fourier transform of the lens aperture illumination function f(x’) rescaled by the magnification factor μ.

[0155] The lens aperture illumination function f(x’) is a complex-valued function, which can be represented by two real-valued functions (real and imaginary parts or amplitude and phase). These two real-valued functions can represent the principal plane electromagnetic waves, which the communication device can radiate, assuming that the communication device is used for transmitting electromagnetic waves.

[0156] The present disclosure has been described in connection with various embodiments as examples and in conjunction with implementations. However, other variations can be understood and effected by those skilled in the art from a study of the drawings, the present disclosure and the independent claims. In the claims, the word “comprising” does not exclude other elements or steps, and the indefinite article “a” or “an” does not exclude a plurality. A single element or other unit can fulfil the functions of several entities or items recited in the claims. The mere fact that certain measures are recited in mutually different dependent claims does not indicate that a combination of these measures cannot be used to advantage.

Claims

1. An antenna system (1), characterized in that, include: Communication equipment (2); Dual reflector antenna (4); Gradient refractive index GRIN lens (3); The communication device (2) is used to transmit main plane electromagnetic waves to the GRIN lens (3); The GRIN lens (3) is used to transform the emitted principal plane electromagnetic wave into a radiated Gaussian beam; The dual reflector antenna (4) is used to convert the radiated Gaussian beam into a subplane electromagnetic wave and to transmit the subplane electromagnetic wave to the outside of the antenna system (1); The communication device (2) is used to change the propagation direction of the transmitted subplane electromagnetic wave by changing the propagation direction of the transmitted primary plane electromagnetic wave.

2. The antenna system (1) according to claim 1, characterized in that, The communication device (2) is a multi-channel communication device (2a) for changing the propagation direction of the transmitted principal plane electromagnetic wave by changing the phase of two or more channels of the multi-channel communication device (2a).

3. The antenna system (1) according to claim 1, characterized in that, The communication device (2) includes a single-channel communication device (2b) and a reflector (2c); The single-channel communication device (2b) is used to transmit the principal plane electromagnetic wave to the GRIN lens (3) via the reflector (2c), wherein the communication device (2) is used to change the propagation direction of the transmitted principal plane electromagnetic wave by rotating the reflector (2c).

4. The antenna system (1) according to any one of claims 1 to 3, characterized in that, The dual-reflector antenna (4) includes a main reflector (4b) and a sub-reflector (4a). The sub-reflector (4a) is used to reflect the radiated Gaussian beam from the GRIN lens (3) to the main reflector (4b). The primary reflector (4b) is used to transform the radiated Gaussian beam into the emitted subplane electromagnetic wave by reflecting the radiated Gaussian beam.

5. The antenna system (1) according to claim 4, characterized in that, The main reflector (4b) and the sub-reflector (4a) are axially symmetrical with respect to a common axis.

6. The antenna system (1) according to claim 4, characterized in that, The main reflector (4b) is an axisymmetric parabolic reflector, and the sub-reflector (4a) is an axisymmetric hyperboloid reflector or an axisymmetric elliptic reflector.

7. The antenna system (1) according to any one of claims 1 to 3, characterized in that, The dual reflector antenna (4) is a defocused dual reflector antenna.

8. The antenna system (1) according to any one of claims 1 to 3, characterized in that, The dual reflector antenna (4) is a Cassegrain dual reflector antenna or a Gregory dual reflector antenna.

9. The antenna system (1) according to claim 4, characterized in that, Both the main reflector (4b) and the sub-reflector (4a) are parabolic cylindrical defocusing reflectors.

10. The antenna system (1) according to claim 4, characterized in that, The parabolic curvature of the main reflector (4b) and the parabolic curvature of the sub-reflector (4a) belong to different mutually orthogonal planes.

11. The antenna system (1) according to any one of 1 to 3, characterized in that, The GRIN lens (3) has multiple elliptical profiles that define regions with different material densities.

12. The antenna system (1) according to any one of 1 to 3, characterized in that, The GRIN lens (3) includes two surfaces (3a, 3b), at least one of which has a refractive index greater than that of air.

13. The antenna system (1) according to any one of 1 to 3, characterized in that, The GRIN lens (3) is used to match the phase center of the radiated Gaussian beam with the focal point of the dual reflector antenna (4) by means of the distributed material density.

14. The antenna system (1) according to any one of 1 to 3, characterized in that, The communication device (2) is used to cause a displacement of the phase center of the Gaussian beam relative to the focal point of the dual reflector antenna (4) by changing the propagation direction of the transmitted principal plane electromagnetic wave using the GRIN lens (3).

15. The antenna system (1) according to claim 14, characterized in that, The communication device (2) is used to cause the displacement of the phase center of the Gaussian beam relative to the focus of the dual reflector antenna (4), such that the greater the displacement of the phase center of the Gaussian beam relative to the focus of the dual reflector antenna (4), the greater the change in the propagation direction of the emitted subplane electromagnetic wave.

16. An antenna system (1), characterized in that, include: Communication equipment (2); Dual reflector antenna (4); Gradient refractive index GRIN lens (3); The dual reflector antenna (4) is used to receive subplane electromagnetic waves from outside the antenna system (1) and convert the received subplane electromagnetic waves into a radiated Gaussian beam. The GRIN lens (3) is used to convert the radiated Gaussian beam into a principal plane electromagnetic wave; The communication device (2) is used for: Receive the main plane electromagnetic wave from the GRIN lens (3); The propagation direction of the received subplane electromagnetic wave is changed by changing the propagation direction of the received primary plane electromagnetic wave.

17. The antenna system (1) according to claim 16, characterized in that, The communication device (2) is a multi-channel communication device (2a) for changing the propagation direction of the received principal plane electromagnetic wave by changing the phase of two or more channels of the multi-channel communication device (2a).

18. The antenna system (1) according to claim 17, characterized in that, The communication device (2) includes a single-channel communication device (2b) and a reflector (2c); The single-channel communication device (2b) is used to receive the principal plane electromagnetic wave from the GRIN lens (3) via the reflector (2c), wherein the communication device (2) is used to change the propagation direction of the received principal plane electromagnetic wave by rotating the reflector (2c).

19. The antenna system (1) according to any one of claims 16 to 18, characterized in that, The dual-reflector antenna (4) includes a main reflector (4b) and a sub-reflector (4a). The primary reflector (4b) is used to transform the received subplane electromagnetic wave into the radiated Gaussian beam by reflecting the received subplane electromagnetic wave to the secondary reflector (4a). The sub-reflector (4a) is used to reflect the radiated Gaussian beam from the main reflector (4b) to the GRIN lens (3).

20. The antenna system (1) according to claim 19, characterized in that, The main reflector (4b) and the sub-reflector (4a) are axially symmetrical with respect to a common axis.

21. The antenna system (1) according to claim 19, characterized in that, The main reflector (4b) is an axisymmetric parabolic reflector, and the sub-reflector (4a) is an axisymmetric hyperboloid reflector or an axisymmetric elliptic reflector.

22. The antenna system (1) according to any one of claims 16 to 18, characterized in that, The dual reflector antenna (4) is a defocused dual reflector antenna.

23. The antenna system (1) according to any one of claims 16 to 18, characterized in that, The dual reflector antenna (4) is a Cassegrain dual reflector antenna or a Gregory dual reflector antenna.

24. The antenna system (1) according to claim 19, characterized in that, Both the main reflector (4b) and the sub-reflector (4a) are parabolic cylindrical defocusing reflectors.

25. The antenna system (1) according to claim 19, characterized in that, The parabolic curvature of the main reflector (4b) and the parabolic curvature of the sub-reflector (4a) belong to different mutually orthogonal planes.

26. The antenna system (1) according to any one of claims 16 to 18, characterized in that, The GRIN lens (3) has multiple elliptical profiles that define regions with different material densities.

27. The antenna system (1) according to any one of claims 16 to 18, characterized in that, The GRIN lens (3) includes two surfaces (3a, 3b), at least one of which has a refractive index greater than that of air.

28. The antenna system (1) according to any one of claims 16 to 18, characterized in that, The GRIN lens (3) is used to match the phase center of the radiated Gaussian beam with the focal point of the dual reflector antenna (4) by means of the distributed material density.

29. The antenna system (1) according to any one of claims 16 to 18, characterized in that, The communication device (2) is used to cause a displacement of the phase center of the Gaussian beam relative to the focal point of the dual reflector antenna (4) by changing the propagation direction of the received principal plane electromagnetic wave using the GRIN lens (3).

30. The antenna system (1) according to claim 29, characterized in that, The communication device (2) is used to cause the displacement of the phase center of the Gaussian beam relative to the focus of the dual reflector antenna (4), such that the greater the displacement of the phase center of the Gaussian beam relative to the focus of the dual reflector antenna (4), the greater the change in the propagation direction of the received subplane electromagnetic wave.

Images