Patent Application
20240014566
The present disclosure relates to an antenna array comprising an integral antenna element structure mounted on a substrate. The disclosure further relates to a method for manufacturing an antenna array.
Antennas are known in the art and used to convert radio frequency fields into alternating current or converting alternating current in to propagating waves at radio frequencies. Antenna arrays with a set of two or more antenna elements are commonly used in various applications to combine or process signals from the antenna array in order to achieve improved performance over that of a single antenna. For instance, they are able to match a radiation pattern to a desired coverage area, changing radiation pattern, adapting to changing signal conditions and some configurations can cover a large bandwidth. Antenna arrays can be described by their radiation patterns and by the type of antenna elements in the system.
A common type of antenna array is the Vivaldi antenna array, also known as a tapered-slot or flared-notch antenna array. Conventionally, the Vivaldi antenna array typically have a radiating part starting with a slot-line which widens in one direction in a tapered notch. The Vivaldi antenna array is usually designed such that each Vivaldi element is fed through a separate radio frequency (RF) connector. This type of design can be applied for frequencies up to 21 GHz. However, for higher frequencies, such as frequencies above 21 GHz, the inter-element distance of the antenna array decreases resulting in that the RF connectors below each antenna element are of a larger size than the antenna elements. This can result in that the RF connector can limit the inter-element distance between the antenna elements and the electronics in an antenna array. Interelement distance larger than half wavelength may result into emergence of grating lobes, depending on the beam steering direction.
Consequently, at higher frequencies, the Vivaldi antenna array will be increasingly complex to manufacture. Also, connectors designed for higher frequencies are more expensive than RF connectors adapted for lower frequencies. This results in that the cost of manufacturing and assembly of an antenna array adapted for higher frequencies would become significant, especially for Vivaldi antenna arrays having a large amount of antenna elements.
Thus, there is room for Vivaldi antenna arrays in the present art to explore the domain of providing an improved Vivaldi antenna array with simplicity in design, assembly and manufacturing compared to previous solutions. More specifically, there is a need in the present art for an improved Vivaldi antenna array for higher frequencies being cost-efficient and having simplified manufacturing and assembly.
Even though some currently known solutions work well in some situations it would be desirable to provide an antenna array that fulfils requirements related to improving the cost-efficiency, assembly and manufacturing of Vivaldi antenna arrays.
It is therefore an object of the present disclosure to provide an antenna array, a method for manufacturing an antenna array, a base station and a vehicle comprising such an antenna array to mitigate, alleviate or eliminate one or more of the above-identified deficiencies and disadvantages.
This object is achieved by means of an antenna array, a method for manufacturing an antenna array, a vehicle and a base station comprising such an antenna array as defined in the appended claims.
The present disclosure is at least partly based on the insight that by providing an antenna array having an integral antenna element structure where the antenna elements, the antenna ground plane and the transition pin are all integral made in one piece, several advantages in terms of cost effectiveness, manufacturing, electrical and thermal properties, and assembly are readily available. In accordance with the disclosure there is provided an antenna array according to claim 1 and a method for manufacturing an antenna array according to claim 15.
The present disclosure provides an antenna array comprising an integral antenna element structure mounted on a substrate. The integral antenna element structure comprises an antenna ground plane having first and second opposing surfaces. The integral antenna element structure further comprises a first set of antenna elements arranged in at least a first and a second row and a second set of antenna elements arranged in at least a first and a second column. The antenna elements extend vertically from the first surface of the antenna ground plane. Each antenna element comprises a first body and an adjacent second body extending from a lower portion to a tapered upper portion forming a radiation-slot intermediate the tapered upper portion of the first and the second body. Further, a first end of the lower portion of the first body forms a common integral part with the first surface of the antenna ground plane and the lower portion of the second body is branched into a first leg and a second leg having a first leg end and a second leg end. Furthermore, a transition pin forms an integral part with said first leg, extending from said first leg end at least partly through a passage in said ground plane, the second leg end being integral with the first surface of the antenna ground plane. The first set of antenna elements are arranged such that the first body and the second body of each adjacent antenna element form a common tapered structure, and the second set of antenna elements are arranged such that the first body and the second body of each adjacent antenna element form a common tapered structure.
A benefit of the antenna array is that the antenna element structure is integral and forms a single piece that comprises a transition pin, a ground plane and antenna elements. Thus, the manufacturing and the assembly of the antenna array is simplified. The antenna array can be manufactured and assembled by mounting two pieces together i.e. the antenna element structure and the substrate. Further, since the antenna array comprises a transition pin instead of a connector, the antenna array is applicable to Ka-band and mmWave frequencies in a more convenient manner compared to previous solutions that comprise separate connectors behind each antenna element. If previous solutions are to be directed to frequencies above 18 GHz, the connector may have a size larger than the antenna elements, limiting the interelement distance, which may lead to larger than half-wave separation between adjacent elements which further may lead to grating lobes. By providing an antenna array with an integral transition pin instead of a connector, the above deficiencies are resolved and other benefits such as reduced weight is provided. Also, the transition pin is cheaper than a connector. Furthermore, the antenna array according to the present disclosure results in a more compact structure compared to previous solutions.
The integral structure described may also lead into better electrical and thermal performance. Separate connectors and cables are typically lossy. Additional losses between the antenna element and transceiver increases power consumption, decreases efficiency, decreases the sensitivity and output power. The transceiver can be in the immediate vicinity of the antenna element in the described solution. This structure minimizes RF losses between the antenna and the transceiver.
Active electronics, especially power amplifiers generate significant amount of heat during operation. To avoid overheating, excess heat must be dissipated. In the integral solution described above, the antenna block is mechanically connected to the printed circuit board, where active electronics is integrated. The antenna block can be fabricated from metal, which is known to be a good thermal conductor. This metal structure may have a good thermal connection to the printed circuit board due to a large contact area and the structure can conduct heat away from active electronics. The legs of the antenna array operate inherently as thermal radiators and cools the structure.
The antenna array according to the present disclosure may be a Vivaldi antenna array or a flared-notch antenna array or a tapered slot antenna array.
The first body and the second body of a common tapered structure of the first set of elements may be perpendicularly conjoined with a corresponding common tapered structure of the second set of elements. Consequently, a common tapered structure of the first set of elements and a corresponding common tapered structure of the second set of elements may form a cross, such that the antenna elements form a grid-like structure on said first surface. This type of structure allows for the antenna array to achieve an even more compact structure.
Further, the first body and the second body may comprise an inner portion and an outer portion, the outer portion extending vertically. Also, the radiation-slot may extend into a sinuous portion towards the first surface of the antenna ground plane.
The sinuous portion may extend into the passage of the ground plane. This structure allows for a simplified structure of the antenna array allowing for even further simplified manufacturing. Since the sinuous portion extends into the passage, it may form a part of the passage allowing the sinuous portion and the passage to be formed at least partly simultaneously during manufacturing of the antenna array.
Further, a cavity may be formed intermediate the first leg and the second leg of the second body. The cavity may extend vertically from the first surface of the antenna ground plane in a tapered manner, forming an arrow-like shape.
Further, the substrate may comprise an electrically conductive pattern, wherein a first surface of said substrate comprises a plurality of feeding pads, each feeding pad being arranged to feed a corresponding transition pin. A benefit of this is that the antenna element structure may be mounted directly to the substrate. Further, such a substrate is convenient to adapt to a corresponding antenna element structure.
The substrate may comprise at least one vertical interconnect access, via arranged to transfer a signal to the feeding pad from a layer below the first surface of the substrate. Allowing the volume of the substrate to be utilized to a large extent. The substrate may be a printed circuit board, PCB.
The antenna array may be configured to transmit and receive wireless signals at a frequency in the range of 21 GHz and 50 GHz. By having a transition pin instead of a connector, higher frequencies such as frequencies in the range of 21 GHz and 50 GHz are achievable without hampering the performance of the antenna array.
The integral antenna array structure may be a metal structure. By having a metal structure combined with the design of the integral antenna element structure the antenna element structure may beneficially draw excess heat from the substrate. Accordingly, the risk of overheating of the antenna array and its electronics is decreased. Electronics may be e.g. amplifiers, phase shifters, vector modulators etc.
The passage may circumferentially enclose the transition pin. This allows for a more stable structure and reduces the risk of having the transition pin to be bent or damaged.
There is also disclosed a vehicle comprising the antenna array as disclosed herein. Further, there is also disclosed a base station comprising the antenna array according to the present disclosure.
Furthermore, there is disclosed a method for manufacturing an antenna array comprising the steps of;
A benefit of the method is that it only requires two major steps, forming the antenna element structure and mounting the antenna element structure to a substrate. Since the antenna ground plane, the transition pin and the elements are all integral with the antenna element structure the time of manufacturing the antenna array is significantly reduced and simplified.
The integral antenna element structure may be formed by additive manufacturing or machining.
The integral antenna element may be mounted on said substrate by soldering, glue or screws.
Further objects, features and advantages of embodiments of the disclosure will appear from the following detailed description, reference being made to the accompanying drawings, in which:
In the following detailed description, some embodiments of the present disclosure will be described. However, it is to be understood that features of the different embodiments are exchangeable between the embodiments and may be combined in different ways, unless anything else is specifically indicated. Even though in the following description, numerous specific details are set forth to provide a more thorough understanding of the provided antenna array, method for manufacturing an antenna array, a base station and a vehicle comprising such an antenna array, it will be apparent to one skilled in the art that the antenna array and the method for manufacturing the antenna array may be realized without these details. In other instances, well known constructions or functions are not described in detail, so as not to obscure the present disclosure.
In the following description of example embodiments, the same reference numerals denote the same or similar components.
The term “array antenna” or “array of antenna elements” or “antenna array” refers to a set of multiple connected antennas which work together as a single antenna. In this disclosure the term antenna array” refers to at least two antenna elements. The term “RF” refers to radio frequency which is an electromagnetic wave having a frequency. An antenna array may be coupled to a feeding system.
The term “connector” or “RF connector” refers to a separate component which may for example connect coaxial cables, which transmit radio frequency signals between at least two points.
The term “radiation slot” refers to a cavity within the antenna element that guides electromagnetic waves from the cavity to be emitted from the antenna element. The cavity may be filled with air.
The term “substrate” refers to a non-conductive or dielectric substrate that may comprise electrically conductive patterns such as electrically conductive tracks. A substrate may further comprise vias and pads, laminated on, under or between different layers of the substrate. It may further comprise electrical components such as amplifiersb switches and DC circuitry.
The term “integral” refers to a unitary or one-piece structure made of a single material and does not include structures formed by e.g. welding, soldering or gluing several pieces together. Thus, the term “integral antenna element structure” refers to that the antenna element structure is a monolithic structure. Accordingly, the term “integral” may be interchanged with the term “monolithic”.
The antenna array 1 as shown in
As shown in
As further shown in
As shown in
Further, it is shown in
Furthermore, a cavity 23 is formed intermediate the first leg 15 and the second leg 16 of the second body 10. The cavity 23 may be arbitrarily shaped. Further, as shown in
The substrate 3 comprises at least one vertical interconnect access, via (not shown) arranged to transfer a signal to the feeding pad 23 from a layer below the first surface 3′ of the substrate 3. Thus, the substrate 3 may have a plurality of signal layers with electrically conductive patterns. The via may be connected to the middle of the feeding pad 23 to a below layer. The term “via” refers to two pads in corresponding positions on different layers of the substrate 3 that are electrically connected by a hole through the substrate 3. Thus, each feeding pad 23, may be connected to a corresponding additional pad (not shown), wherein the additional pad is positioned in another layer of the substrate below the first surface 3′. The feeding pads 23 and each additional pad may be connected by a hole that is made conductive by electroplating, the hole may be positioned in the middle of the feeding pad 23. The via in the substrate may be of different types, such as a through hole via, a blind via, a buried via or any other type of via.
Further, as shown in
The substrate 3 as shown in
As further shown in
The antenna array 1 as disclosed herein may be configured to transmit and receive wireless signals at a frequency in the range of 21 GHz and 50 GHz. The antenna array 1 as disclosed herein having an integral antenna element structure 2 mounted to a substrate 3 may beneficially transmit and receive wireless signals at a frequency range of 21 GHz and 50 GHz since there is no need for a connector that limits the inter-element spacing of the antenna array 7 or that increases the price of the antenna array 1.
The antenna array 1 may have half-wavelength separation between adjacent antenna elements 7 in each row/column. Further, the antenna array 1 may be a dual-polarized antenna array 1.
The integral antenna element structure 2 may be a metal structure. This combined with the integral design of the antenna element structure 2 may provide the benefit of the integral antenna element structure 2 drawing excess heat from the substrate 3.
According to some embodiments, the antenna array 1 is arranged in a radar system.
Further, the lower portion of the second body is branched into a first leg and a second leg having a first leg end and a second leg end, wherein a transition pin forms an integral part with said first leg, extending from said first leg end at least partly through a passage in said ground plane, the second leg end being integral with the first surface of the antenna ground plane. The first set of antenna elements are arranged such that the first body and the second body of each adjacent antenna element form a common tapered structure and the second set of antenna elements are arranged such that the first body and the second body of each adjacent antenna element form a common tapered structure.
The method 100 further comprises a second step of:
The integral antenna element structure 2 may be formed by machining or additive manufacturing. Thus, a single manufacturing equipment such as a milling machine for machining or a 3D printer for additive manufacturing may form the integral antenna element structure 2. Resulting in a cheap and fast manufacturing of the antenna element structure 2. Further, the design of the antenna element structure 2 may beneficially be modified (for instance to adapt it to a PCB) since 3D model data and material supply may be the only requirement for the manufacturing of the integral antenna element structure 2. Further, the integral antenna element 2 may be mounted on said substrate 3 by soldering, glue, screws or any other suitable method.
| Number | Date | Country | Kind |
|---|---|---|---|
| 2000147-5 | Aug 2020 | SE | national |
| Filing Document | Filing Date | Country | Kind |
|---|---|---|---|
| PCT/SE2021/050815 | 8/19/2021 | WO |
