Waveguide Termination Configuration for Array Antennas

Abstract

An array antenna (100) having a layered structure. The array antenna includes a radiating layer (110) including a plurality of radiating elements (111) and a distribution layer (120) facing the radiating layer. The distribution layer is configured to distribute a radio frequency (RF) signal to the plurality of radiating elements. The distribution layer includes at least one distribution layer feed (121) and at least one first waveguide (122) configured to guide the RF signal between the at least one distribution layer feed and the at least one radiating element. The array antenna further includes at least one second waveguide (130) coupled to the at least one distribution layer feed (121). Either the first waveguide (122) or the second waveguide (130) includes a plastic having a first type of surface treatment (313), the first type of surface treatment including metallization. At least one of the radiating elements is a dummy element terminated by an attenuation section coupled to the dummy element and disposed in one of the plastic-containing waveguides (122, 130). The attenuation section includes a second type of surface treatment (314) configured to attenuate the RF signal.

Description

Technical Field

[0001] The present disclosure relates to antenna arrays, particularly waveguide-based array antennas and waveguides in general. Antenna arrays are suitable for use, for example, in transmitters and receivers for telecommunications and radar transmitters and receivers.

Background Art

[0002] Wireless communication networks include radio frequency transmitters and receivers such as radio base stations used in cellular access networks, microwave radio link transmitters and receivers used, for example, as backhaul to core networks, and satellite transmitters and receivers that communicate with artificial satellites in orbit. Radar transmitters and receivers are also radio frequency transmitters and receivers because they transmit and receive radio frequency (RF) signals, i.e., electromagnetic signals.

[0003] The radiation arrangement of a transmitter and receiver often includes an array antenna because, for example, high directivity and beam steering, and / or shaping of the radiation pattern for multiple beams can be highly controlled by the array. An array antenna generally includes a plurality of antenna elements arranged at intervals smaller than the wavelength corresponding to the operating frequency of the transmitter and receiver.

[0004] It is desirable for each antenna element in the array to behave in the same way. Here, behavior means radiation pattern, impedance matching, etc. It is particularly desirable for each element in each row in an array including slot antennas to behave in the same way. However, the outermost elements (or rows) actually exhibit non-equivalent performance because they have fewer adjacent elements compared to the central elements (or rows) of the array.

[0005] This can be solved by adding a new set of elements to the outermost side and changing those elements into dummy elements (or dummy rows). The dummy elements are internally terminated by a matched attenuator. By doing so, the adjacent active elements see the dummy elements as normal active elements.

[0006] An improved waveguide terminator configuration is needed for array antennas. [Overview of the project] [Problems that the invention aims to solve]

[0007] This disclosure aims to provide an improved waveguide terminator for array antennas, that is, one that is low-cost, easy to manufacture, and exhibits good performance. [Means for solving the problem]

[0008] This objective is at least partially achieved by an array antenna having a layered structure. The array antenna includes a radiating layer containing a plurality of radiating elements and a distribution layer opposite the radiating layer. The distribution layer is configured to distribute a radio frequency (RF) signal to the plurality of radiating elements. The distribution layer includes at least one distribution layer feed point and at least one first waveguide configured to guide the RF signal between the at least one distribution layer feed point and at least one radiating element. The array antenna further includes at least one second waveguide connected to at least one distribution layer feed point. Either the first waveguide or the second waveguide contains plastic with a first type of surface treatment, the first type of surface treatment including metallization. Furthermore, at least one radiating element is a dummy element terminated by an attenuation section. The attenuation section is connected to the dummy element and located in one of the waveguides containing plastic. The attenuation section contains a second type of surface treatment configured to attenuate the RF signal.

[0009] Attenuation sections are used to create attenuators, to obtain attenuation functions, or to obtain termination functions, and are directly integrated into array antennas, which is advantageous. Attenuation sections are also easy to manufacture and cost-effective.

[0010] Depending on the embodiment, the attenuation section is adapted to a desirable system impedance such as 50 ohms, but can take any value. Therefore, the attenuation section can be used as a terminator that is well adapted to the waveguide.

[0011] To terminate the dummy element, the attenuation section can be placed on the radiating layer of the array antenna, preferably within the distribution layer, and more preferably within a second waveguide connected to the distribution layer. The goal of the termination is to indicate that the dummy element is equivalent to any of the other adjacent elements.

[0012] According to one embodiment, the first type of surface treatment includes priming and metallization. The primer can be used to allow the desired metal to adhere better to the plastic part.

[0013] In some embodiments, the second type of surface treatment includes untreated plastic, meaning the damping zone is composed of an unmetallized zone. This can be achieved by masking the damping zone during the metallization process. This enables a cost-effective and simple manufacturing process.

[0014] In some embodiments, the second type of surface treatment includes a primer, meaning that the attenuation section includes a primer, but does not include metallization with a commonly desired metal such as copper, silver, or gold. In this way, the entire waveguide, including the plastic, can first be coated with the primer. Subsequently, the attenuation section can be masked so as not to be coated with metallization. This provides a simplified manufacturing process. The primer on the attenuation section can advantageously shield the attenuation section from the outside, for example, from adjacent waveguides. This reduces undesirable coupling.

[0015] In some embodiments, the second type of surface treatment includes metallization, and the thickness of the metallization is configured to attenuate the RF signal. This provides good attenuation performance. Advantageously, the thickness of the coating does not substantially change the surface current distribution and therefore does not substantially change the characteristic impedance of the waveguide. Thus, the thin metallization of the second surface treatment eliminates the discontinuity due to the transition from the coating of the first surface treatment, which means that compatibility is maintained. Furthermore, by metallizing the attenuated section relatively thinly, the attenuated section can be advantageously shielded from the outside, for example, from adjacent waveguides. This reduces undesirable coupling.

[0016] Depending on the embodiment, one of the waveguides containing plastic contains lossy plastic. This is advantageous because it attenuates unwanted signals such as leakage from the attenuation section.

[0017] In one embodiment, at least one dummy element is placed on the outer periphery of a plurality of radiating elements. This improves the behavior of each active antenna element adjacent to the dummy element relative to the remaining elements in the array antenna.

[0018] In one embodiment, the array antenna includes multiple rows of radiating elements, at least one of which is a dummy row terminated by an attenuation section. In a further embodiment, at least one dummy row is positioned on the outer perimeter of the multiple rows. This improves the behavior of each active row adjacent to the dummy row with respect to the remaining rows in the array antenna.

[0019] In some embodiments, the first waveguide is a gap waveguide, and includes a metamaterial structure configured such that either the radiating layer or the distributing layer forms a gap waveguide between the distributing layer and the radiating layer. The metamaterial structure is also configured to prevent electromagnetic radiation from propagating in directions other than through the distributing layer feed section and radiating element in the operating frequency band. The metamaterial structure efficiently seals the gap waveguide so that electromagnetic energy can pass through along the intended waveguide path largely unimpeded, rather than in other directions. The arrangement of the radiating layer and the distributing layer can be non-contact, and no electrical contact is required between these layers. This is advantageous because it does not require high-precision assembly, and these two layers may simply be joined to each other by fastening means such as bolts or similar. Furthermore, since the repeating structure seals the transition section non-contact, there is no need to verify electrical contact.

[0020] In some embodiments, the metamaterial structure includes a repeating structure of protruding elements. The repeating structure may be directly machined, for example, one of the layers. This is advantageous because such machining can be performed in a highly mechanically accurate and cost-effective manner. Another advantage is that such integrally molded repeating structures are mechanically stable.

[0021] This specification also discloses telecommunications transceivers or radar transceivers that include the antenna array described above.

[0022] This specification also discloses a waveguide for inducing radio frequency (RF) signals, the waveguide comprising a metallized plastic. The waveguide further comprises an attenuation section comprising a second type of surface treatment, the remainder of the waveguide comprising a first type of surface treatment. The first type of surface treatment comprises metallization, and the second type of surface treatment is configured to attenuate RF signals.

[0023] The present disclosure utilizes plastic surface treatment to create attenuators, obtain attenuation functions, or obtain termination functions, where the plastic is directly incorporated into the waveguide, which is advantageous. According to an aspect, the attenuation section is adapted to a desired system impedance such as 50 ohms, but can take any value. Thus, the attenuation section can be used as a terminator that fits well with the waveguide.

[0024] According to an aspect, the waveguide includes a first layer and a second layer facing each other. Either the first layer or the second layer includes a metamaterial structure configured to form a gap waveguide in the middle between the first layer and the second layer. Also, the metamaterial structure is configured to prevent electromagnetic radiation from propagating in a direction other than along the intended waveguide path from the gap waveguide in the operating frequency band.

[0025] The metamaterial structure efficiently seals the gap waveguide so that electromagnetic energy can pass through it approximately unobstructed along the intended waveguide path rather than in other directions. The arrangement of these layers can be non-contact, and electrical contact is not required between these layers. This is an advantage because it does not require high-precision assembly, and these two layers may be simply joined to each other by fastening means such as bolts or the like. Furthermore, since the repetitive structure seals the transition in a non-contact manner, there is no need to check for electrical contact.

[0026] According to an aspect, the metamaterial structure of the waveguide includes a repetitive structure of protruding elements. The repetitive structure may be directly machined, for example, into one of the layers. This is an advantage because such machining can be performed in a highly mechanically accurate and cost-effective manner. Also, such an integrally formed repetitive structure is mechanically stable, which is an advantage.

[0027] According to an aspect, the first type of surface treatment of the waveguide includes a primer.

[0028] According to an aspect, the surface treatment of the second type of waveguide includes untreated plastic. According to a further aspect, the surface treatment of the second type of waveguide includes a primer. According to another aspect, the surface treatment of the second type of waveguide includes metallization, and the thickness of the metallization is configured to attenuate the RF signal.

[0029] This specification also discloses a method of manufacturing a waveguide including plastic. This method includes performing surface treatment on the surface of the attenuation section of the waveguide with a second type of surface treatment, performing surface treatment on the remaining portion of the waveguide with a first type of surface treatment, and the first type of surface treatment includes metallization, and the second type of surface treatment is configured to attenuate the RF signal.

[0030] The method disclosed in this specification is related to the same advantages as those described above in relation to different measuring devices. This specification further discloses a control unit configured to control some of the operations described herein.

[0031] Generally, all terms used in the claims should be interpreted according to their ordinary meaning in the technical field, unless explicitly defined otherwise herein. All references to "an element, apparatus, component, means, step, etc." preceded by "a / an / the" should be straightforwardly interpreted as referring to at least one instance of the element, apparatus, component, means, step, unless otherwise explicitly specified. Any step of any method disclosed herein need not be performed in the order disclosed, unless explicitly specified. Further features of the present invention and advantages associated with the present invention will become apparent upon examination of the appended claims and the following description. Those skilled in the art will understand that different features of the present invention can be combined to create embodiments different from those described below without departing from the scope of the present invention.

Brief Description of the Drawings

[0032] The present disclosure will now be described in more detail with reference to the attached drawings.

[0033] [Figure 1A] An example antenna array is shown. [Figure 1B] An example antenna array is shown. [Figure 2] An example antenna array is shown. [Figure 3A] An example antenna array is shown. [Figure 3B] An example antenna array is shown. [Figure 4A] An example waveguide is shown. [Figure 4B] An example waveguide is shown. [Figure 5A] An example waveguide is shown. [Figure 5B] An example waveguide is shown. [Figure 6] This is a flowchart of the method. [Modes for carrying out the invention]

[0034] The embodiments of this disclosure will now be described in more detail with reference to the accompanying drawings. However, the various apparatuses and methods disclosed herein can be implemented in many different forms and should not be construed as being limited to the embodiments described herein. Wherever in the drawings, similar figures refer to similar elements.

[0035] The technical terms used herein are for illustrative purposes only and are not intended to limit the invention. As used herein, the singular forms “a,” “an,” and “the” also include the plural forms unless the context explicitly indicates otherwise.

[0036] As already mentioned, improved waveguide termination configurations are needed for array antennas. In typical antenna arrays, low frequencies (<6 GHz) can be easily terminated using, for example, PCB or coaxial terminations with surface-mount attenuators. Waveguide-based arrays can utilize electromagnetic absorbers. This can be done using many different materials and in many different ways, such as using wedge-shaped absorbers at the shorted ends of waveguides. However, using absorbers is expensive and significantly complicates the manufacture of array antennas. Furthermore, achieving sufficient attenuation using absorbers can be difficult due to limited space. Also, manufacturing tolerances can be a problem with absorbers, especially at high frequencies, such as millimeter waves.

[0037] This disclosure utilizes surface treatments of plastics that are directly incorporated into array antennas to create attenuators, to obtain attenuation functions, or to obtain termination functions. More specifically, an antenna, a waveguide portion of an antenna, or a waveguide generally includes a metallized plastic and a portion hereafter referred to as an attenuation section, which has a different surface treatment than the rest of the antenna, the waveguide portion of an antenna, the antenna, or a general waveguide. For example, the attenuation section may simply be an unmetallized section or a section with only a primer. In different examples, the attenuation section may be metallized with a different material. In another example, the attenuation section may be metallized such that the corresponding metal coating is thinner. Generally, the attenuation section is configured to attenuate RF signals by resistive loss.

[0038] Depending on the embodiment, the attenuation section is adapted to a desirable system impedance such as 50 ohms, but can take any value. Therefore, the attenuation section can be used as a terminator that is well adapted to the waveguide.

[0039] The attenuation section of the disclosed waveguide can be used to terminate a radiating element in an array antenna, and thus this radiating element can be made a dummy element. Alternatively, the attenuation section can be used to terminate an entire column, and thus the entire column can be made a dummy column. To terminate a dummy element, the attenuation section can be placed directly on the radiating layer of the array antenna, preferably in the distribution layer, and more preferably in a waveguide connected to the distribution layer. The goal of termination is to indicate that the dummy element is equivalent to any of the other adjacent elements.

[0040] According to one aspect of the present invention, an array antenna 100 having a layered structure as shown in the examples in Figures 1A, 1B, 2, 3A, and 3B is disclosed herein. The array antenna includes a radiating layer 110 containing a plurality of radiating elements 111, and a distribution layer 120 opposite the radiating layer. The distribution layer is configured to distribute radio frequency (RF) signals to the plurality of radiating elements 111. The distribution layer includes at least one distribution layer feed point 121 and at least one first waveguide 122 configured to guide RF signals between the at least one distribution layer feed point and at least one radiating element. The array antenna further includes at least one second waveguide 130 connected to at least one distribution layer feed point 121. Either the first waveguide 122 or the second waveguide 130 includes plastic with a first type of surface treatment 313. In other words, one or both of the first waveguide and the second waveguide include the first type of surface treatment. Here, the first type of surface treatment includes metallization. At least one radiating element is a dummy element terminated by an attenuation section 312. The attenuation section is connected to the dummy element and located in one of the waveguides 122, 130, which includes plastic. Preferably, the waveguide with the attenuation section is a hollow waveguide and can be filled with air or some dielectric material. Examples of such waveguides are rectangular waveguides, circular waveguides, ridge waveguides, gap waveguides, and ridge-gap waveguides. The first waveguide in the distribution layer can confine electromagnetic waves by utilizing a portion of the radiating layer. For example, a portion of the radiating layer may constitute one of the waveguide walls in a rectangular waveguide. Furthermore, the first waveguide may be a ridge waveguide in which one or more ridges are located on the distribution layer and / or radiating layer. Furthermore, the attenuation section includes a second type of surface treatment 314 configured to attenuate RF signals.

[0041] The disclosed array antenna is highly cost-effective because it does not require additional components such as surface-mount attenuators or electromagnetic absorbers. Furthermore, the array antenna is easy to manufacture, which further reduces costs in various ways. In addition, the disclosed array enables excellent performance at high frequencies, such as millimeter waves.

[0042] In general, as used herein, a waveguide is a structure that guides electromagnetic waves. A waveguide can be a hollow rectangular tube, as shown in Figures 4A and 4B. The cross-section can be many other shapes, such as circular or more common shapes. The tube can be hollow or filled with a dielectric material. A waveguide may also be a gap waveguide.

[0043] A layer is a planar element having two faces, and its thickness is related to the size of the faces. The thickness is much smaller than the size of the faces; that is, a layer is a flat or nearly flat element, i.e., it has a curved shape. According to some embodiments, layers are rectangular or square. However, more general shapes, including circular or elliptical disks, are also applicable.

[0044] At least one distribution layer feed section 121 may be a waveguide arranged as a through-hole configured to transmit radio frequency signals through the distribution layer, as shown in Figure 2. The distribution layer feed section may also include an extension of the first waveguide 122 for sending RF signals away from the distribution layer, as shown in Figures 3A and 3B.

[0045] Referring to Figure 2, the attenuation section can be located on the ridge gap waveguide 122 of the distribution layer. Alternatively, the attenuation section can be located on a waveguide connected to the distribution layer feed section (not shown). In this way, all elements in the figure are well fitted and terminated. Such a column would be useful as a dummy column in an array antenna containing multiple columns. Referring to Figures 3A and 3B, the attenuation section is located on the second waveguide 130 of the leftmost column in a three-column array.

[0046] The first waveguide 122 or the second waveguide 130, which does not contain a radiating layer and / or plastic, may include cast, molded, punched, and / or machined metal, such as copper or brass. The metal may include a coating having high electrical conductivity, such as silver or copper coated aluminum, or silver or copper coated zinc.

[0047] Either the first waveguide 122 or the second waveguide 130 contains a plastic that has undergone a first type of surface treatment 313, the first type of surface treatment including metallization. The purpose of metallization is to allow electromagnetic waves to propagate through the waveguide, thereby enabling the array antenna to function. Metallization is generally known and therefore is described only briefly herein. The radiating layer may also contain metallized plastic. Metallization of plastic can be carried out in many different ways. The plastic can be metallized directly, or a primer can be applied to the plastic surface first, and then the plastic surface can be coated with the desired metal. Desirable metals for metallization of plastic are those with low loss and high electrical conductivity, such as copper, silver, and gold. Many other metals and alloys are also possible. In this specification, metallization is interpreted broadly. Metallization may also include placing a conductive polymer on the surface. Such materials have the desired metallic conductivity and are therefore included in the term "metallized".

[0048] While many other materials are possible, suitable primers include nickel, chromium, palladium, and titanium. Primers can be used to ensure that the desired metal adheres better to the plastic part. There are many different methods for shaping a plastic surface to the desired form, such as casting, molding, and / or machining. In this specification, plastics are broadly interpreted as a variety of synthetic and semi-synthetic organic compounds that can be molded into solids.

[0049] At least one of the multiple radiating elements 111 in the disclosed antenna array 100 may include an aperture. The aperture in the radiating layer 110 may be, for example, a groove-shaped aperture extending through the radiating layer. The groove-shaped aperture is preferably rectangular, although other shapes such as square, round, or more general shapes are also possible. The groove-shaped aperture is preferably small compared to the size of the radiating layer 110 and is positioned on parallel lines on the radiating layer, although other arrangements are possible. All radiating elements include grooves, and the radiating layer 110 may include a metal sheet (e.g., copper or brass). The radiating layer may include a sublayer of cavities configured to form cavities between each radiating element and the distribution layer. It is understood that other types of radiating elements are also possible.

[0050] The second waveguide can be connected to at least one distribution layer feed section 121 in many different ways. For example, the second waveguide may simply include a rectangular waveguide directly connected to the distribution layer feed section. Exemplary waveguides are shown in Figures 4A and 4B. Furthermore, the second waveguide 130 can be located within a layer opposite to the distribution layer 120, such as a printed circuit board (PCB) layer 131 and / or a shielding layer 132, or any other type of distribution layer / feed layer.

[0051] The radiating layer can be formed as a separate component from the distribution layer, as shown in Figure 2. However, the radiating layer and the distribution layer can be formed integrally within a single component. Similarly, the second waveguide can be separate from or integral with the distribution layer feed section. Figures 3A and 3B show an example where the second waveguide is integrally formed with the distribution layer feed section.

[0052] In some embodiments, the first type of surface treatment 313 includes a primer. In other words, the metallization of the first type of surface treatment includes the step of applying a primer before metallization with the desired metal.

[0053] The second type of surface treatment 314 may include untreated plastic, meaning the attenuation section is composed of an unmetallized section. In this way, the attenuation section can be masked so as not to be coated with metallization (and ultimately primer). This provides a simple manufacturing process. The surface treatment process for the antenna array can be carried out according to the following steps: The second surface-treated section is masked, and the first surface-treated section is coated with metallization of the desired thickness. Here, an optional primer can be coated onto these sections before metallization. This process involves masking only once, which is an advantage because the process is simple and precise.

[0054] In some embodiments, the second type of surface treatment 314 includes a primer, meaning that the attenuation section includes the primer, but does not include metallization with a commonly desired metal such as copper, silver, or gold. In this way, the entire waveguide, including the plastic, can first be coated with the primer. Subsequently, the attenuation section can be masked so as not to be coated with metallization. This provides a simple manufacturing process. The primer on the attenuation section can advantageously shield the attenuation section from the outside, for example, from adjacent waveguides. This can reduce undesirable coupling. The surface treatment process for the antenna array can be carried out according to the following steps: First, all parts that have undergone the first and second surface treatments are coated with the primer. Finally, the parts that have undergone the second surface treatment are masked, and the parts that have undergone the first surface treatment are coated with metallization of the desired thickness. This process involves masking only once.

[0055] The second type of surface treatment 314 may include metallization. In this case, the thickness of the metallization is configured to attenuate the RF signal. By metallizing the attenuated section relatively thinly, the attenuated section can be advantageously shielded from the outside, for example, from adjacent waveguides. This can reduce undesirable coupling. The surface treatment process for the antenna array can be carried out according to the following steps. First, a primer can be optionally coated on all parts that have undergone the first and second surface treatments. Next, a thin layer of metallization is coated on all parts. Finally, the parts that have undergone the second surface treatment are masked, and the parts that have undergone the first surface treatment are coated with metallization of the desired thickness. This process involves masking only once.

[0056] Depending on the embodiment, either the first surface treatment or the second surface treatment may include a protective coating. This protective coating can be used for corrosion prevention or protection from mechanical wear, etc. Furthermore, any of the coating steps described herein may include the application of multiple layers. For example, the primer coating may include the application of several layers.

[0057] As already mentioned, the second type of surface treatment 314 may include a thin layer of metallization configured to attenuate RF signals. Here, the attenuation section is a surface coated with one (or more) thin layers of metallization on top of the plastic. The thickness configured to attenuate RF signals relates to the so-called skin thickness. Skin thickness describes how deeply the electric field propagates within the material and depends on the frequency and material properties (the higher the frequency, the greater the electric field contained on the surface). In the absence of magnetic and dielectric losses, the skin thickness can be expressed as follows:

[0058]

number

[0059] Here, ρ is the resistivity of the conductor, ω is the angular frequency, μ is the permeability of the conductor, and ε is the permittivity of the conductor.

[0060] In conventional waveguides, when low loss is desired, the metal (or conductive material) needs to be relatively thick, meaning a thickness several times greater than the skin thickness. Attenuation sections may instead include a thin metal coating to provide high loss and excellent termination. In some embodiments, the thickness of the metallization configured to attenuate RF signals is less than three times the skin thickness, preferably less than the skin thickness, and more preferably less than one-third of the skin thickness.

[0061] The losses caused by the thin thickness allow for use with materials that have low electrical conductivity.

[0062] If the metallized coating has a thickness equal to or less than the skin thickness, the electric field penetrates the entire metallized coating, and the current is also present on the opposite side of the coating (i.e., the plastic side), and this current can potentially radiate electromagnetic waves. Such radiation is a type of leakage and can be undesirable. However, such leakage can also be suppressed by external means. Leakage can reduce the intensity of electromagnetic waves traveling along the attenuation section, while resistive losses typically attenuate the waves significantly. Furthermore, it is sometimes desirable not to make the metallization in the attenuation section too thin, because the metallized coating provides some shielding, for example, from adjacent waveguides or from self-interference due to leakage. Therefore, there is a range of thicknesses that is thin enough to provide sufficient attenuation without being affected by harmful leakage or shielding problems.

[0063] Advantageously, the coating thickness does not substantially alter the surface current distribution, and therefore does not substantially alter the characteristic impedance. This means there is no discontinuity from the normal coating, which means that compatibility is maintained.

[0064] The attenuation section may contain a poor conductor with a normal thickness, i.e., several times the skin thickness. In this case, there are no problems with shielding or leakage.

[0065] As already mentioned, the second surface treatment can be untreated plastic, i.e., no coating. This may result in some reflection during the transition from the first to the second surface treatment. However, a stepwise transition between the two surface treatments and / or a gradual change in the waveguide shape can also improve the fit. The shape can be modified by flaring, similar to that of a horn-shaped waveguide. This can be thought of as providing an antenna for the purpose of attenuating intensity. Furthermore, either waveguide 122, 130 containing plastic may contain lossy plastic. In this way, unwanted leakage is attenuated. Including lossy plastic in waveguides containing attenuation sections is particularly advantageous. Lossy plastic may include, for example, a material with high dielectric loss, and / or may be infused with carbon or similar materials.

[0066] At least one dummy element can be placed on the outer perimeter of multiple radiating elements 111. In other words, the dummy element is placed connected to the interface of the radiating layer. In one embodiment, all elements on the outer perimeter are dummy elements. In that case, all active elements are surrounded by dummy elements. Here, surrounding means forming a boundary around the surrounded object.

[0067] The array antenna 100 may include multiple rows of radiating elements 111. In this case, at least one row is a dummy row terminated by an attenuation section. In some cases, to achieve the desired effect of all active elements in the array behaving similarly, it may be necessary to place dummy elements along the two outermost rows of the array antenna. This may be the case for arrays that include slot antennas. Therefore, at least one dummy row can be placed on the outer perimeter of multiple rows.

[0068] In one embodiment, the first waveguide is a gap waveguide, and either the radiating layer 110 or the distributing layer 120 includes a metamaterial structure 124 configured to form a gap waveguide between the distributing layer 120 and the radiating layer 110. The metamaterial structure is also configured to prevent electromagnetic radiation from propagating in directions other than the direction through which the gap waveguide passes the distributing layer feed section 121 and the radiating element 111 in the operating frequency band.

[0069] Due to the metamaterial structure, the distribution layer 120 is positioned either in direct contact with the radiating layer 100 or at a slight distance from the radiating layer 110, where this distance is less than one-quarter of the wavelength of the operating center frequency of the antenna array 100. Direct contact may mean that only a portion of the two layers are in contact.

[0070] The use of metamaterial structures in the distribution layer reduces losses from the waveguide and minimizes interference between radio frequency signals in adjacent waveguides. This is advantageous because it allows for the maintenance of a high signal-to-noise ratio through the use and placement of metamaterial structures in the distribution layer. Another advantage is that electrical contact is not required between the two layers constituting the waveguide. This is an advantage because it eliminates the need for high-precision assembly due to the absence of electrical contact verification. However, electrical contact between multiple layers is also an option.

[0071] Metamaterial structures are configured to form high-impedance surfaces, such as artificial magnetic conductors (AMCs). When the high impedance faces a conductive surface (i.e., a low-impedance surface, such as a perfect conductor (PEC) in the ideal case), and the two surfaces are separated by a distance less than a quarter of the wavelength of the center frequency, then, ideally, all parallel plate modes are blocked in that frequency band, so there are no electromagnetic waves in the operating frequency band propagating along or between the intermediate surfaces. In other words, the high-impedance and low-impedance surfaces form an electromagnetic bandgap between the two surfaces. The two surfaces can also be placed directly adjacent to each other, i.e., electrically connected to each other. The center frequency is usually in the middle of the operating frequency band. In a realistic scenario, electromagnetic waves in the operating frequency band are attenuated according to the length along the intermediate surface. Hereinafter, attenuation is interpreted as significantly reducing the amplitude or intensity of electromagnetic radiation, such as radio frequency signals. Attenuation is preferably complete, in which case attenuation and blocking are synonymous, but it is understood that such complete attenuation is not always achievable.

[0072] A gap waveguide can be formed by replacing the waveguide walls with a metamaterial structure. Such a waveguide may include a ridge to form a ridge-gap waveguide (RGW).

[0073] An example of the dimensions for a rectangular distribution layer 120 is a thickness of 5 mm and a length and width of 100 mm. However, the distribution layer is not necessarily rectangular; other shapes such as circles or hexagons are also possible.

[0074] The metamaterial structure 124 may include a repeating structure of protruding elements 125. Such protruding elements can be integrally formed on layers 110, 120 containing the metamaterial structure 124, i.e., on the radiating layer 110 and / or the distributing layer 120. Either the distributing layer 120 or the radiating layer 110 optionally includes at least one waveguide ridge 123 that forms at least one first gap waveguide.

[0075] As already mentioned, the second waveguide 130 can be placed on a printed circuit board (PCB) layer 131 facing the distribution layer 120 and / or on a shielding layer 132 facing the PCB layer 131. Therefore, the antenna array 100 may further include a printed circuit board (PCB) layer 131 facing the distribution layer 120, and the PCB layer includes at least one PCB layer feeding section.

[0076] By using a metamaterial structure in the distribution layer, highly efficient coupling is possible when the signal is transferred from the PCB layer feeding section on the PCB layer 131 through the distribution feeding section 224 to at least one first waveguide, thereby reducing losses. The PCB layer 131 optionally includes at least one RF integrated circuit (IC) located on one or both sides of the PCB layer. At least one PCB layer feeding section can be configured to transmit a radio frequency signal from the RF IC to the opposite side of the PCB, to the distribution layer. For example, at least one PCB layer feeding section is a through-hole connected to a corresponding opening in the distribution layer 120, which is fed by at least one microstrip line. Alternatively, or in combination, at least one PCB layer feeding section can be configured to transmit a radio frequency signal from the RF IC to the side of the PCB facing the distribution layer, to the distribution layer. In one embodiment, at least one PCB layer feeding section is configured to transmit a radio frequency signal away from the antenna array 100, for example, to a modem. The PCB layer may include a pressed or etched metal plate as a ground plane or a complementary ground plane.

[0077] The antenna array 100 may further include a shielding layer 132 facing the PCB layer 131. The shielding layer 132 optionally includes a second metamaterial structure configured to form a gap waveguide between the shielding layer 132 and the PCB layer 131. The gap waveguide may constitute a second waveguide 130. The second metamaterial structure is also configured to prevent electromagnetic radiation from propagating in directions other than through the gap waveguide to at least one PCB layer feed point in the operating frequency band. The second metamaterial structure enables a compact design with low loss and low leakage, i.e., less unwanted electromagnetic propagation, for example, between adjacent waveguides or between adjacent RFICs. Furthermore, the second metamaterial structure shields the PCB layer from electromagnetic radiation outside the antenna array.

[0078] The second metamaterial structure optionally includes a repeating structure of protruding elements, and the PCB layer optionally includes a ground plane and at least one planar transmission line to form at least one gap waveguide between the shielding layer 132 and the PCB layer 131. The gap waveguide may be, for example, an inverted microstrip gap waveguide. The gap waveguide may be the second waveguide 130. The shielding layer may include two types of protruding elements, for example, narrow, tall pins and wide, short pins. The wider, shorter pins can be configured to fit into an RFIC between the shielding layer and the PCB layer. The pins may be in contact with the RFIC for the purpose of heat transfer.

[0079] In one embodiment, the distribution layer 120 includes a third metamaterial structure, which is located on the opposite side of the first metamaterial structure 124, i.e., the third metamaterial structure faces the PCB layer 131. This allows multiple gap waveguides to be formed between the distribution layer 120 and the PCB layer 131. These gap waveguides can be used to couple electromagnetic signals between the RFIC on the PCB layer 131 and the PCB layer feeding section. Any such gap waveguide can constitute the second waveguide 130. The third metamaterial structure enables a compact design with low loss and low leakage, i.e., less unwanted electromagnetic propagation, for example, between adjacent waveguides or between adjacent RFICs. Furthermore, the third metamaterial structure shields the PCB layer from electromagnetic radiation outside the antenna array.

[0080] According to one embodiment, the telecommunications transceiver or radar transceiver includes an antenna array 100.

[0081] Furthermore, this specification also discloses a method for manufacturing an array antenna (100) having a layered structure. This method is The process involves preparing a radiation layer 110 containing multiple radiation elements 111, The distribution layer 120 is positioned opposite the radiating layer, and the distribution layer is configured to distribute radio frequency (RF) signals to a plurality of radiating elements 111, and the distribution layer includes at least one distribution layer feed unit 121 and at least one first waveguide 122 configured to guide the RF signals between at least one distribution layer feed unit and at least one radiating element. At least one second waveguide 130 is arranged to be connected to at least one distribution layer power supply section 121. Includes, Either the first waveguide 122 or the second waveguide 130 contains plastic, and the method further, Surface treatment of a waveguide containing plastic with a first type of surface treatment 313 including metallization, Includes, At least one radiating element is a dummy element terminated by attenuation section 312, and the method further, The arrangement involves placing an attenuation section in either of the waveguides 122 or 130, which are connected to a dummy element and include plastic, wherein the attenuation section includes a second type of surface treatment 314 configured to attenuate RF signals. Includes.

[0082] This specification also discloses waveguides 300, 400 for inducing radio frequency (RF) signals, which include metallized plastic. The waveguide further includes an attenuation section 312. The attenuation section includes a second type of surface treatment 314, and the remainder of the waveguide includes a first type of surface treatment 313. The first type of surface treatment includes metallization, and the second type of surface treatment is configured to attenuate RF signals.

[0083] The disclosed waveguides 300 and 400 may be rectangular waveguides, circular waveguides, or waveguides based on metamaterial structures such as repeating protruding pins. Many other types of waveguides are also conceivable. Figures 4A, 4B, 5A, and 5B show different examples of the disclosed waveguides.

[0084] In some embodiments, waveguides 300 and 400 include a first layer 511 and a second layer 512 facing each other. Either the first or second layer includes a metamaterial structure 521 configured to form a gap waveguide between the first layer 511 and the second layer 512. The metamaterial structure is also configured to prevent electromagnetic radiation from propagating from the gap waveguide in directions other than along the intended waveguide path in the operating frequency band.

[0085] An intended waveguide is a path intended to induce electromagnetic radiation. For example, if a microwave device includes two separate waveguides, these two waveguides are intended to be separated, and the intended waveguide is along each waveguide. The metamaterial structure 521 separates the two waveguides. Another example of an intended waveguide is a power grid in a company, where one waveguide connects the power distribution unit and the radiating element, and the other waveguide connects different integrated components on the PCB.

[0086] Due to the metamaterial structure, the first layer 511 and the second layer 512 are positioned either in direct contact with each other or at a small distance from each other, the distance being less than one-quarter of the wavelength of the operating center frequencies of the disclosed waveguides 300, 400. Direct contact may mean that only a portion of the two layers are in contact.

[0087] The use of a metamaterial structure in either the first layer 511 or the second layer 512 reduces losses from the waveguide and minimizes interference between radio frequency signals in adjacent waveguides or circuits. One advantage is that electrical contact is not required between the two layers that make up the waveguide. This is an advantage because it eliminates the need for high-precision assembly since electrical contact does not need to be verified. However, electrical contact between multiple layers is also an option.

[0088] The metamaterial structure 521 of the waveguides 300, 400 may include a repeating structure of protruding elements 522. Such protruding elements can be integrally formed on layers 511, 512 containing the metamaterial structure 521. Either the first layer 511 or the second layer 512 optionally includes at least one waveguide ridge 523 that forms at least one first gap waveguide between the first layer 511 and the second layer 512.

[0089] The first type of surface treatment 313 of the waveguides 300, 400 may include a primer. In other words, the metallization of the first type of surface treatment includes the step of applying a primer before metallization with the desired metal.

[0090] The second type of surface treatment 314 of waveguides 300 and 400 may include untreated plastic, that is, the attenuation section may be composed of untreated plastic.

[0091] In some embodiments, the second type of surface treatment 314 of the waveguides 300 and 400 may include a primer, that is, the attenuation section includes a primer, but does not include metallization with a commonly desired metal such as copper, silver, or gold.

[0092] The second type of surface treatment 314 of the waveguides 300 and 400 may include metallization. In this case, the thickness of the metallization is configured to attenuate the RF signal.

[0093] This specification also discloses a method for manufacturing waveguides 300, 400 containing plastic, as shown in Figure 6. This method is (S1) Performing surface treatment on the attenuation section 312 of the waveguide with a second type of surface treatment 314, The surface treatment of the remaining portion 411 of the waveguide is performed with the first type of surface treatment 313 (S2), Includes, The first type of surface treatment includes metallization, and the second type of surface treatment is configured to attenuate RF signals.

Claims

1. A radiation layer (110) containing multiple radiating elements (111), A distribution layer (120) facing the radiating layer, configured to distribute radio frequency (RF) signals to the plurality of radiating elements (111), and including at least one distribution layer power supply unit (121) and at least one first waveguide (122) configured to guide the RF signals between the at least one distribution layer power supply unit and at least one of the radiating elements, At least one second waveguide (130) connected to the at least one distribution layer power supply section (121), An array antenna (100) having a layered structure including, Either the first waveguide (122) or the second waveguide (130) includes a plastic that has undergone a first type of surface treatment (313) including metallization. At least one of the radiating elements is a dummy element terminated by an attenuation section (312), the attenuation section is connected to the dummy element and arranged in either of the first and second waveguides (122, 130) which include plastic, and the attenuation section is subjected to a second type of surface treatment (314) to attenuate the RF signal. Array antenna (100).

2. The array antenna (100) according to claim 1, wherein the first type of surface treatment (313) includes arranging a primer and metallizing.

3. A radiation layer (110) including a plurality of radiation elements (111), A distribution layer (120) facing the radiating layer, configured to distribute radio frequency (RF) signals to the plurality of radiating elements (111), and including at least one distribution layer power supply unit (121) and at least one first waveguide (122) configured to guide the RF signals between the at least one distribution layer power supply unit and at least one of the radiating elements, At least one second waveguide (130) connected to the at least one distribution layer power supply section (121), An array antenna (100) having a layered structure including, Either the first waveguide (122) or the second waveguide (130) includes a plastic that has undergone a first type of surface treatment (313) including metallization. At least one of the radiating elements is a dummy element terminated by an attenuation section (312), the attenuation section being connected to the dummy element and located in either of the first and second waveguides (122, 130) which include plastic. The aforementioned attenuation section is comprised of a non-metallized section, in the array antenna (100).

4. The array antenna (100) according to claim 1, wherein the second type of surface treatment (314) includes arranging a primer.

5. The array antenna (100) according to claim 1, wherein the second type of surface treatment (314) includes metallization, and the thickness of the metallization of the second type of surface treatment (314) is configured to attenuate the RF signal.

6. The array antenna (100) according to claim 1, wherein one of the waveguides (122, 130) containing plastic contains a high dielectric loss material and / or a carbon-injected plastic.

7. The array antenna (100) according to any one of claims 1 to 6, wherein the at least one dummy element is arranged on the outer periphery of the plurality of radiating elements (111).

8. The array antenna (100) according to claim 1, comprising a plurality of rows of radiating elements (111), wherein at least one of the rows is a dummy row terminated by the attenuation interval.

9. The array antenna (100) according to claim 8, wherein at least one of the dummy rows is arranged on the outer periphery of the plurality of rows.

10. The array antenna (100) according to claim 1, wherein the first waveguide is a gap waveguide, and either the radiating layer (110) or the distributing layer (120) includes a metamaterial structure (124) configured to form the gap waveguide between the distributing layer (120) and the radiating layer (110), and the metamaterial structure is also configured to prevent electromagnetic radiation from propagating in directions other than the direction through the distributing layer feed section (121) and the radiating element (111) in the operating frequency band.

11. The array antenna (100) according to claim 10, wherein the metamaterial structure (124) includes a repeating structure of protruding elements (125).

12. A telecommunications transceiver or radar transceiver comprising the antenna array (100) described in claim 1.

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