The present disclosure relates to antenna arrays having baffle boxes to reduce mutual coupling.
This section provides background information related to the present disclosure which is not necessarily prior art.
Mutual coupling is a significant problem in antenna array design and in systems using antenna arrays. High levels of mutual coupling are equivalent to low isolation, which is an important parameter in radar and communication systems. In particular, it can be relatively difficult to maintain a high isolation between both co-polar antenna ports and cross-polar antenna ports in an antenna array.
This section provides a general summary of the disclosure, and is not a comprehensive disclosure of its full scope or all of its features.
An exemplary embodiment of an antenna array includes at least two or more radiating elements coupled to a ground plane. The two or more radiating elements include a first radiating element separated from a second radiating element by at least one wall that extends away from the ground plane between the first and second radiating elements. The wall may be operable for reducing mutual coupling between the first and second radiating element.
In another exemplary embodiment, a dual polarization antenna array includes a plurality of radiating elements forming a planar array extending in two orthogonal directions. Each radiating element is within a baffle box having side walls and a bottom coupled to a substantially planar ground plane. The sidewalls extend between corresponding pairs of adjacent radiating elements. The baffle boxes may be operable to reduce the mutual coupling between the radiating elements.
Another exemplary embodiment of a dual polarization antenna array includes a plurality of radiating elements forming a planar array extending in two orthogonal directions. Each radiating element is within a baffle box having side walls and a bottom coupled to a ground plane. The radiating elements are operable for receiving and/or transmitting two different polarizations. Each radiating element is fed by two probes such that each probe excites one of two orthogonal polarizations. The sidewalls extend between corresponding pairs of adjacent radiating elements. The baffle boxes may be operable to reduce the mutual coupling between the radiating elements.
Further areas of applicability will become apparent from the description provided herein. The description and specific examples in this summary are intended for purposes of illustration only and are not intended to limit the scope of the present disclosure.
The drawings described herein are for illustrative purposes only of selected embodiments and not all possible implementations, and are not intended to limit the scope of the present disclosure.
Corresponding reference numerals indicate corresponding parts throughout the several views of the drawings.
Example embodiments will now be described more fully with reference to the accompanying drawings.
Exemplary embodiments of the present disclosure relate to antenna arrays or systems that include two or more radiating elements (e.g., patches, etc.), where shielding or baffle walls are between the radiating elements to reduce the mutual coupling and hence increase the port-to-port isolation. In various exemplary embodiments disclosed herein, the shielding or baffle walls are parts of boxes (also referred to herein as baffle boxes), where the boxes are placed on a relatively large ground plane common to all the radiating elements. The boxes may be generally rectangular, or they may have any other suitable non-rectangular shape (e.g., triangular or hexagonal when viewed from above, etc.) depending on the particular configuration of the antenna array. In addition, the walls of a baffle box may also be different on different sides. For example, the walls of a baffle box may vary in height and/or shape. In addition, horizontal, vertical, diagonal, etc. slots may be provided in the baffle walls to change the mutual coupling between different radiating elements. One or more walls may be configured such that it is slanted and not perpendicular to the ground plane.
As disclosed herein, the walls of the baffle boxes help to reduce the mutual coupling between radiating elements inside the boxes. In various embodiments, the walls of the boxes may be made sufficiently high so as to obscure the direct path from a first radiating element placed in a first baffle box to a second radiating element placed in a second baffle box. For example, in various embodiments the walls of the boxes may be at least as tall as the radiating element(s) disposed within the boxes formed by the walls (e.g., the walls have a height above a ground plane at least as high as a distance between the radiating element(s) and the ground plane, the walls extend higher over the ground plane than the radiating element(s), etc.).
As disclosed herein, exemplary embodiments of antenna arrays/systems may include a large number of radiating elements (e.g., patches, etc.) arranged in a relative large array (e.g., the 16×4 array shown in
In various embodiments, the walls between the radiating elements may be defined by or be an integral part of the baffle boxes in which the radiating elements are housed. In such embodiments, the baffle boxes may be attached to a common ground plane and/or to each other using electrically non-conductive adhesive tape, electrically-conductive adhesive tapes, other adhesives besides tapes, mechanical fasteners (e.g., screws, rivets, etc.), welding, soldering, among other suitable means for attaching the walls to the ground plane. In addition, other embodiments may include the baffle boxes being consolidated or integrally formed with the ground plane assembly such that the baffle boxes and ground plane assembly are a single component or have a monolithic construction, such as by using a suitable manufacturing process like casting, machining, metalized injection molding, etc. As recognized by the inventors hereof, the use of relatively thin electrically non-conductive adhesive tape causes the capacitance between the baffle box and the ground plane to become very large so that an effective ground path is created at microwave frequencies.
Aspects of the present disclosure may be especially helpful when the radiating elements operate in dual polarization. In such an antenna, some or all of the radiating elements are adapted to transmit and receive electromagnetic signals of two orthogonal polarizations. Such elements may be realized using patch radiators with two probes (e.g., coaxial probes, etc.) feeding two orthogonal states. Another way to create such a dual polarized radiator is to use two co-located orthogonal dipoles.
In various embodiments, an antenna array may be configured for use with a Chinese TD-SCDMA (Time Division Synchronous Code Division Multiple Access) system and/or Chinese TD-LTE (Time Division Long Term Evolution) systems in the frequency bandwidth of about 1880 megahertz to about 2400 megahertz. Alternative embodiments may be configured for use with other systems and/or for operation in other frequency bandwidths.
With reference now to the figures,
A wide range of electrically-conductive materials (e.g., metals, alloys, etc.) may be used for making the baffle box 1. In various embodiments, the baffle box 1 is made of sheet metal. In other embodiments, the baffle box 1 is made of an alloy or other suitable material.
Also shown in
With further reference to the embodiment illustrated in
In some exemplary embodiments, the baffle boxes 301 and 307 may be formed such that the common baffle wall 309 is a single wall between the baffle boxes 301 and 307. For example, the baffle boxes 301 and 307 may be integrally or monolithically formed together with a single, common baffle wall 309 therebetween. Or, the baffle boxes 301 and 307 may be formed such that either or both of the baffle boxes 301 and 307 does not include the common baffle wall 309. In this latter example, the baffle wall 309 would then be attached to one or both baffle boxes 301 and 307 and/or to a ground plane, such as by electrically non-conductive adhesive tape, electrically-conductive adhesive tape, other adhesives besides tapes, mechanical fasteners (e.g., screws, rivets, etc.), welding, soldering, among other suitable means for attaching the wall to the ground plane. For other exemplary embodiments, the baffle boxes may be formed separately and/or independently, and then the baffle boxes may be placed relative to each other such that their respective sidewalls abut each other to form a baffle wall between the baffle boxes. In any event, a wide range of materials may be used for the baffle boxes, such as metals, alloys, and other suitable materials. In addition, each baffle box does not need to be configured identically to the other baffle box(es) of the antenna array. For example, a baffle box may have a different shape (e.g., non-rectangular, walls of varying heights, walls that are not perpendicular to the ground plane, etc.) and/or may be made out of a different material than another baffle box of the antenna array. In addition, other embodiments may include the baffle boxes being consolidated or integrally formed with the ground plane assembly such that the baffle boxes and ground plane assembly are a single component or have a monolithic construction, such as by using a suitable manufacturing process like casting, machining, metalized injection molding, etc.
With reference now to
With reference back to
Continuing with the description of the computer simulation model shown in
Again, however, each patch 805, 808 is fed by two probes 811, 812 and 813, 814 that excite one of two orthogonal polarizations. More specifically, the patch 805 is fed by probes 811 and 812 extending vertically from the ground plane and patch 805, and that provide two orthogonal slant 45 degree polarizations. The patch 808 is fed by probes 813 and 814 extending vertically from the ground plane and patch 808, and that provide two orthogonal slant 45 degree polarizations. Each patch 805, 808 has a length of about 55 millimeters and a width of about 55 millimeters. Each patch 805, 808 is placed about 10 millimeters above the ground plane. The centers of the patches 805, 808 are separated or spaced apart by a distance of about 75 millimeters. Also in this model, the ports are numbered from top to bottom as P1, P2, P3, P4.
As shown by the computer simulation results, the overall coupling is reduced by the baffles even though one component actually increases slightly. In practice, the radiating elements or patches of the antenna array would be tuned differently for an antenna array that has baffle boxes as compared to an antenna array that doesn't have baffle boxes, which thus make it relatively difficult to make direct comparisons between an antenna array with baffle boxes and an antenna array without baffle boxes.
The specific materials and dimensions provided herein are for purposes of illustration only as an antenna array may be configured from different materials and/or with different dimensions depending, for example, on the particular end use and/or frequencies intended for the antenna array.
Example embodiments are provided so that this disclosure will be thorough, and will fully convey the scope to those who are skilled in the art. Numerous specific details are set forth such as examples of specific components, devices, and methods, to provide a thorough understanding of embodiments of the present disclosure. It will be apparent to those skilled in the art that specific details need not be employed, that example embodiments may be embodied in many different forms and that neither should be construed to limit the scope of the disclosure. In some example embodiments, well-known processes, well-known device structures, and well-known technologies are not described in detail.
The terminology used herein is for the purpose of describing particular example embodiments only and is not intended to be limiting. As used herein, the singular forms “a”, “an” and “the” may be intended to include the plural forms as well, unless the context clearly indicates otherwise. The terms “comprises,” “comprising,” “including,” and “having,” are inclusive and therefore specify the presence of stated features, integers, steps, operations, elements, and/or components, but do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and/or groups thereof. Similarly, the terms “can” and “may” and their variants are intended to be non-limiting, such that recitation that an embodiment can or may comprise certain elements or features does not exclude other embodiments of the present technology that do not contain those elements or features. The method steps, processes, and operations described herein are not to be construed as necessarily requiring their performance in the particular order discussed or illustrated, unless specifically identified as an order of performance. It is also to be understood that additional or alternative steps may be employed.
When an element or layer is referred to as being “on”, “engaged to”, “connected to” or “coupled to” another element or layer, it may be directly on, engaged, connected or coupled to the other element or layer, or intervening elements or layers may be present. In contrast, when an element is referred to as being “directly on,” “directly engaged to”, “directly connected to” or “directly coupled to” another element or layer, there may be no intervening elements or layers present. Other words used to describe the relationship between elements should be interpreted in a like fashion (e.g., “between” versus “directly between,” “adjacent” versus “directly adjacent,” etc.). As used herein, the term “and/or” includes any and all combinations of one or more of the associated listed items. Terms such as “generally”, “about”, and “substantially” may be used herein to mean within manufacturing tolerances.
Although the terms first, second, third, etc. may be used herein to describe various elements, components, regions, layers and/or sections, these elements, components, regions, layers and/or sections should not be limited by these terms. These terms may be only used to distinguish one element, component, region, layer or section from another region, layer or section. Terms such as “first,” “second,” and other numerical terms when used herein do not imply a sequence or order unless clearly indicated by the context. Thus, a first element, component, region, layer or section discussed below could be termed a second element, component, region, layer or section without departing from the teachings of the example embodiments.
Spatially relative terms, such as “inner,” “outer,” “beneath”, “below”, “lower”, “above”, “upper” and the like, may be used herein for ease of description to describe one element or feature's relationship to another element(s) or feature(s) as illustrated in the figures. Spatially relative terms may be intended to encompass different orientations of the device in use or operation in addition to the orientation depicted in the figures. For example, if the device in the figures is turned over, elements described as “below” or “beneath” other elements or features would then be oriented “above” the other elements or features. Thus, the example term “below” can encompass both an orientation of above and below. The device may be otherwise oriented (rotated 90 degrees or at other orientations) and the spatially relative descriptors used herein interpreted accordingly.
The headings (such as “Background” and “Summary”) and sub-headings used herein are intended only for general organization of topics within the present technology, and are not intended to limit the disclosure of the present technology or any aspect thereof. In particular, subject matter disclosed in the “Background” may include novel technology and may not constitute a recitation of prior art. Subject matter disclosed in the “Summary” is not an exhaustive or complete disclosure of the entire scope of the technology or any embodiments thereof.
Any citation of references herein does not constitute an admission that those references are prior art or have any relevance to the patentability of the technology disclosed herein. Any discussion of the content of references cited in the Background is intended merely to provide a general summary of assertions made by the authors of the references, and does not constitute an admission as to the accuracy of the content of such references.
As used herein, the words “preferred” and “preferably” refer to embodiments of the technology that afford certain benefits, under certain circumstances. But other embodiments may also be preferred, under the same or other circumstances. Furthermore, the recitation of one or more preferred embodiments does not imply that other embodiments are not useful, and is not intended to exclude other embodiments from the scope of the technology.
Disclosure of values and ranges of values for specific parameters (such as temperatures, molecular weights, weight percentages, etc.) are not exclusive of other values and ranges of values useful herein. It is envisioned that two or more specific exemplified values for a given parameter may define endpoints for a range of values that may be claimed for the parameter. For example, if Parameter X is exemplified herein to have value A and also exemplified to have value Z, it is envisioned that parameter X may have a range of values from about A to about Z. Similarly, it is envisioned that disclosure of two or more ranges of values for a parameter (whether such ranges are nested, overlapping or distinct) subsume all possible combination of ranges for the value that might be claimed using endpoints of the disclosed ranges. For example, if parameter X is exemplified herein to have values in the range of 1-10, or 2-9, or 3-8, it is also envisioned that Parameter X may have other ranges of values including 1-9, 1-8, 1-3, 1-2, 2-10, 2-8, 2-3, 3-10, and 3-9.
The foregoing description of the embodiments has been provided for purposes of illustration and description. It is not intended to be exhaustive or to limit the invention. Individual elements or features of a particular embodiment are generally not limited to that particular embodiment, but, where applicable, are interchangeable and can be used in a selected embodiment, even if not specifically shown or described. The same may also be varied in many ways. Such variations are not to be regarded as a departure from the invention, and all such modifications are intended to be included within the scope of the invention.
This application is a continuation of PCT International Application No. PCT/US2010/046701 filed Aug. 25, 2010 (Publication No. WO2011/031499), which claims priority to U.S. Provisional Application No. 61/275,049 filed Aug. 25, 2009. The entire disclosures of the above applications are incorporated herein by reference.
Number | Date | Country | |
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61275049 | Aug 2009 | US |
Number | Date | Country | |
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Parent | PCT/US2010/046701 | Aug 2010 | US |
Child | 13404269 | US |