The present invention is generally related to antennas, and more particularly is related to providing antenna radiation pattern control.
The wireless industry is continuously developing systems with higher data rates to satisfy the need for increased data capacity. In order to achieve higher over-the-air data transmission rates, the number of used channels is increased (i.e., higher over-the-air data rate sectorization) and a higher order modulation is used. In addition, it may be useful to alternate polarization between sectors or use polarization diversity, to enhance throughput.
Unfortunately, with an increase in the number of channels used for data transmission, interference between channels is required to be addressed. As an example, providers of wireless telecommunication technologies are required to ensure that they provide for proper wireless coverage within a specific frequency band, while minimizing interference with other frequency bands. In fact, interfering with other frequency bands may result in breaching of licenses associated with providing communication capabilities within a specific coverage area.
In order to minimize interference, a base station antenna may be required to illuminate a desired sector of transmission as uniformly as possible, while suppressing energy radiated in other directions. Unless controlled, energy may leak into undesired directions, forming small auxiliary beams called sidelobes. It is desirable to minimize or eliminate these sidelobes in order to minimize interference.
Dual polarization antennas transmit the electromagnetic energy in two orthogonal polarizations that are typically horizontal and vertical, but could also be left and right hand circular, or +/−45 degrees. The horizontally polarized component is oriented in a generally horizontal direction and the vertically polarized component is oriented in a generally vertical direction. In addition, the horizontally and vertically polarized components are oriented as orthogonal to one another. Unfortunately, controlling the distribution of radiated energy from a dual polarization antenna is difficult since vertical and horizontal polarized components experience different boundary conditions at material interfaces such as metal and plastic surfaces.
Multiple Input Multiple Output (MIMO) based systems are relatively new. They employ space-time processing to combine multiple signals in a fashion that increases total system throughput. The use of dual polarized antennas for diversity applications is well known to the industry. For example, in cellular telephony dual polarized +/−45 degree antennas are often used for diversity applications. However, their use in MIMO based systems has not been widely explored. In contrast to the antennas used for basic diversity techniques, we find that vertical/horizontal dual polarized antennas are preferred for MIMO based systems. This is due to the fact that most scatterers are either vertically or horizontally oriented. Hence, the maximum differences between signals is realized when vertical/horizontal antennas are used. This results in maximum MIMO system gain.
Thus, a heretofore unaddressed need exists in the industry to address the aforementioned deficiencies and inadequacies.
Embodiments of the present invention provide an antenna and method for providing radiation pattern control. Briefly described, in architecture, one embodiment of the antenna, among others, can be implemented as follows. The antenna for providing radiation pattern control contains an antenna housing. The antenna housing includes a mounting surface and a plurality of reflective wings extending from the mounting surface. The antenna housing has an inner surface and an outer surface. At least one linear element is located above the inner surface. A radiation element is situated along the mounting surface so as to allow said antenna housing to control a pattern of radiation emitted by said radiation element.
As mentioned above, the present invention can also be viewed as providing methods for providing radiation pattern control. In this regard, one embodiment of such a method, among others, can be broadly summarized by the following steps: transmitting electromagnetic energy from at least one radiator, the electromagnetic energy comprising a vertical electric field component and a horizontal electric field component; and controlling a pattern of radiation emitted by said at least one radiator through use of a plurality of reflective wings and at least one linear element.
Other systems, methods, features, and advantages of the present invention will be or become apparent to one with skill in the art upon examination of the following drawings and detailed description. It is intended that all such additional systems, methods, features, and advantages be included within this description, be within the scope of the present invention, and be protected by the accompanying claims.
Many aspects of the invention can be better understood with reference to the following drawings. The components in the drawings are not necessarily to scale, emphasis instead being placed upon clearly illustrating the principles of the present invention. Moreover, in the drawings, like reference numerals designate corresponding parts throughout the several views.
The following describes a system and method for providing radiation pattern control via an antenna.
The antenna 100 contains an antenna housing 120 and a radiation element 200. It should be noted that the radiation element 200 is shown as being located beneath a cover portion 121 of the antenna housing 120. The antenna housing 120, which is further illustrated by the schematic diagrams of
The cover portion 121 may be made of many different materials such as, but not limited to, thermoplastics such as different grades of ABS, polycarbonate, polyethylene, polypropylene, or different grades of fabrics or skins, as well as fiberglass reinforced plastics. Specifically, the cover portion 121 of the antenna housing 120 is made of a material that allows electromagnetic energy to flow there through, without significant interference to the electromagnetic radiation pattern provided by the antenna housing 120.
As is shown by
The antenna housing 120 and linear elements 150, 152 may be fabricated from different materials. Specifically, the material used to fabricate the antenna housing 120 and linear elements 150, 152 is capable of reflecting electromagnetic energy so as to provide a required radiation pattern. As an example, the antenna housing 120 and linear elements 150, 152 may be fabricated from aluminum, magnesium, galvanized steel, stainless steel, or conductively coated plastics. In addition, the shape of the antenna housing 120 and linear elements 150, 152 is dependent upon a required resulting radiation pattern. As an example, while the linear elements 150, 152 are shown to have a circular cross-sectional shape, any cross-sectional shape may be used to achieve objectives of the present invention. Possibilities for cross-sectional shapes of the linear elements 150, 152 include, but are not limited to, rectangular cross-sections, V-shaped cross-sections, and U-shaped cross-sections.
As has been mentioned above, the outer body 122 of the antenna housing 120 contains a plurality of wings 128 (described in detail below) that assist in providing radiation pattern control by reflecting electromagnetic radiation emitted by the radiation element 200 (
Describing the inner surface 130 of the outer body 122, starting from a central point 129 of the inner surface 130, located on the mounting surface 126 of the central trough 132 and extending to the left, a first step 134 of one of the wings 128 begins a distance X1 from the central point 129 of the inner surface 130 with a first step first side portion 136. The first step first side portion 136 extends vertically from the mounting surface 126 of the central trough 132, a distance Y1. In accordance with the first exemplary embodiment of the invention, the first step first side portion 136 meets the mounting surface 126 of the central trough 132 at approximately ninety degrees.
As is shown by
The first step 134 also contains a first step second side portion 140, which extends vertically downward, away from the first step top portion 138. In accordance with the first exemplary embodiment of the invention, the first step second side portion 140 meets the first step top portion 138 at an angle of approximately ninety degrees. The first step second side portion 140 meets a second step top portion 142, where the second step top portion 142 extends horizontally and meets the first step second side portion 140 at approximately ninety degrees. A second step first side portion 144 extends vertically downward from the second step top portion 142 and meets the second step top portion 142 at approximately ninety degrees.
The second step first side portion 144, a first left bottom surface 146 and a third step first side portion 148 define a first left trough 149 located within the outer body 122 of the antenna housing 120. In accordance with the first exemplary embodiment of the invention, the third step first side portion 148 meets the first left bottom surface 146 at approximately ninety degrees. The third step first side portion 148 extends upward in a vertical direction and meets a third step top portion 151, where the third step top portion 151 extends in a horizontal direction. The third step first side portion 148 meets the third step top portion 151 at approximately ninety degrees.
A third step second side portion 153 meets the third step top portion 151 and extends downward in a vertical direction. As is shown by
The third step second side portion 153, a second left bottom surface 154, and a fourth step first side portion 156 define a second left trough 158 located within the outer body 122 of the antenna housing 120. In accordance with the first exemplary embodiment of the invention, the fourth step first side portion 156 meets the second left bottom surface 154 at approximately ninety degrees.
The fourth step first side portion 156 extends upward in a vertical direction and meets a fourth step top portion 160, where the fourth step top portion 160 extends in a horizontal direction. The fourth step first side portion 156 meets the fourth step top portion 160 at approximately ninety degrees. A fourth step second side portion 162 meets the fourth step top portion 160 and extends vertically downward from the fourth step top portion 160. In accordance with the first exemplary embodiment of the invention, the fourth step second side portion 162 meets the fourth step top portion 160 at approximately ninety degrees. The fourth step first side portion 156, the fourth step top portion 160, and the fourth step second side portion 162 define a fourth step 155 of the outer body 122.
Returning to the central point 129 of the inner surface 130, it should be noted that everything to the right of the central point 129 of the inner surface 130, which has not been described thus far, is a mirror image of everything to the left of the central point 129 of the inner surface 130, as described hereinabove.
Describing the inner surface 130 of the outer body 122, starting from the central point 129 of the inner surface 130, located on the mounting surface 126 of the central trough 132 and extending to the right, a fifth step 170 begins a distance X2 from the central point 129 of the inner surface 130 with a fifth step first side portion 172. It should be noted that distance X1 is preferably equal to distance X2, although in accordance with alternative embodiments of the invention, the distances may be different.
The fifth step first side portion 172 extends vertically from the mounting surface 126 of the central trough 132, a distance Y2. In accordance with the first exemplary embodiment of the invention, the fifth step first side portion 172 meets the mounting surface 126 of the central trough 132 at approximately ninety degrees.
As is shown by
The fifth step 170 also contains a fifth step second side portion 176, which extends vertically downward, away from the fifth step top portion 174. In accordance with the first exemplary embodiment of the invention, the fifth step second side portion 176 meets the fifth step top portion 174 at an angle of approximately ninety degrees. The fifth step second side portion 176 meets a sixth step top portion 180, where the sixth step top portion 180 extends horizontally and meets the fifth step second side portion 176 at approximately ninety degrees. A sixth step first side portion 182 extends vertically downward from the sixth step top portion 180 and meets the sixth step top portion 180 at approximately ninety degrees.
The sixth step first side portion 182, a first right bottom surface 184 and a seventh step first side portion 186 define a first right trough 190 located within the outer body 122 of the antenna housing 120. In accordance with the first exemplary embodiment of the invention, the seventh step first side portion 186 meets the first right bottom surface 184 at approximately ninety degrees. The seventh step first side portion 186 extends upward in a vertical direction and meets a seventh step top portion 188, where the seventh step top portion 188 extends in a horizontal direction. The seventh step first side portion 186 meets the seventh step top portion 188 at approximately ninety degrees.
A seventh step second side portion 191 meets the seventh step top portion 188 and extends downward in a vertical direction. As is shown by
The seventh step second side portion 191, a second right bottom surface 192, and an eighth step first side portion 194 define a second right trough 196 located within the outer body 122 of the antenna housing 120. In accordance with the first exemplary embodiment of the invention, the seventh step first side portion 194 meets the second right bottom surface 192 at approximately ninety degrees.
The eighth step first side portion 194 extends upward in a vertical direction and meets an eighth step top portion 198, where the eighth step top portion 198 extends in a horizontal direction. The eighth step first side portion 194 meets the eighth step top portion 198 at approximately ninety degrees. An eighth step second side portion 197 meets the eighth step top portion 198 and extends vertically downward from the eighth step top portion 198. In accordance with the first exemplary embodiment of the invention, the eighth step second side portion 197 meets the eighth step top portion 198 at approximately ninety degrees. The eighth step first side portion 194, the eighth step top portion 198, and the eighth step second side portion 197 define an eighth step 199 of the outer body 122.
In accordance with the first exemplary embodiment of the invention, the radiators 210 are etched into a printed circuit board 212 so as to allow the radiators 210 to emit electromagnetic radiation provided by a source of the vertical polarized components and a source of the horizontal polarized components. Specifically, the radiators 210 may be made of any material capable of emitting electromagnetic radiation. In addition, the radiators 210 may be created by use of a method different from etching. One having ordinary skill in the art would know of such other methods of creation. It should also be noted that the radiators 210 may be provided in a form different from located on a printed circuit board and may include patch antennas, dipoles, and slots, as are known to those having ordinary skill in the art.
The electromagnetic energy is distributed from the connectors 250 and 252 (
Referring to both
Conductive paths are located within the radiation element 200, from each of the conductive points 262, 264 to specific radiators 210 located on the printed circuit board 212. As a result of the conductive paths, each radiator 210 emits a vertical electric field component and a horizontal electric field component independent of each other.
As mentioned above, the two linear elements 150, 152 extending above the inner surface 130 of the outer body 122 allow shaping of a radiation pattern, where the vertical electric field component of radiation interacts with the linear elements 150, 152 and is shaped accordingly, and where the horizontal electrical field component of the radiation is primarily unaffected by the linear elements 150, 152. The reason for this can be found in the expressions for the scattering cross-section of a thin conducting cylinder. The scattering cross-section diminishes as the inverse of the logarithm of the cylinder radius squared for the vertical polarization, and for the horizontal polarization the scattering cross section diminishes as the cylinder radius to the fourth power. For a cylinder diameter that is 1/20th of the wavelength of the electromagnetic wave the power in the vertically polarized scattered wave is several orders of magnitude higher than the power in the horizontally polarized scattered wave. The electric field scattered off the linear elements 150, 152 helps shape the radiation pattern in a direct manner by adding to the radiation pattern directly, and indirectly by redirecting energy to the reflector wings 128 that then reflects the electric field in a controlled manner that adds to the radiation pattern. The exact location of the linear elements 150, 152 can be determined either by calculating the electromagnetic fields by solving Maxwell's equations, or by empirical trials based on electromagnetic field measurements.
In addition, the linear elements 150, 152 act to suppress side lobes as is further illustrated by
It should be noted that the antenna 100 polarized nearfields of
Describing the outer body 322, starting from the mounting surface 326 of the central trough 332 and extending to the left, a first step of one of the wings 328 begins with a first step first side portion 336. The first step first side portion 336 extends vertically from the mounting surface 326 of the central trough 332. In accordance with the second exemplary embodiment of the invention, the first step first side portion 336 meets the mounting surface 326 of the central trough 332 at an approximately ninety degree angle.
As is shown by
The first step top portion 338 also connects to a first step second side portion 340, which extends vertically downward, away from the first step top portion 338. In accordance with the second exemplary embodiment of the invention, the first step second side portion 340 meets the first step top portion 338 at an angle of approximately ninety degrees. The first step second side portion 340 meets a first arcuate wing portion 342, where the first arcuate wing portion 342 extends horizontally and meets the first step second side portion 340 at an angle of approximately 105 degrees. As is shown in
As is shown by
The second step top portion 374 also connects to a second step second side portion 376, which extends vertically downward, away from the second step top portion 374. In accordance with the second exemplary embodiment of the invention, the second step second side portion 376 meets the second step top portion 374 at an angle of approximately ninety degrees. The second step second side portion 376 meets a second arcuate wing portion 380, where the second arcuate wing portion 380 extends horizontally and meets the second step second side portion 376 at an angle of approximately one hundred five degrees.
Describing the outer body 422, starting from the mounting surface 426 of the central trough 432 and extending to the left, a first step of one of the wings 428 begins with a first step first side portion 436. The first step first side portion 436 extends vertically from the mounting surface 426 of the central trough 432. In accordance with the third exemplary embodiment of the invention, the first step first side portion 436 meets the mounting surface 426 of the central trough 432 at an approximately ninety degree angle.
As is shown by
The first step top portion 438 also connects to a first step second side portion 440, which extends vertically downward, away from the first step top portion 438. In accordance with the third exemplary embodiment of the invention, the first step second side portion 440 meets the first step top portion 438 at an angle of approximately ninety degrees. The first step second side portion 440 meets a first arcuate wing portion 442, where the first arcuate wing portion 442 extends horizontally and meets the first step second side portion 440 at an angle of approximately 105 degrees. As is shown in
As is shown by
The second step top portion 474 also connects to a second step second side portion 476, which extends vertically downward, away from the second step top portion 474. In accordance with the third exemplary embodiment of the invention, the second step second side portion 476 meets the second step top portion 474 at an angle of approximately ninety degrees. The second step second side portion 476 meets a second arcuate wing portion 480, where the second arcuate wing portion 480 extends horizontally and meets the second step second side portion 476 at an angle of approximately one hundred five degrees.
While the second and third exemplary embodiments show two different styles of arcuate wing portions 328, 428, these examples are not intended to be limiting and other styles of arcuate wing portions 328, 428 are considered to be within the scope of the present invention.
Describing the outer body 522, starting from the mounting surface 526 and extending to the left, a first step of one of the wings 528 begins with a first step portion 536. The first step portion 536 extends angularly from the mounting surface 526. In accordance with the fourth exemplary embodiment of the invention, the first step portion 536 meets the mounting surface 526 at an approximately two hundred twenty-five degree angle.
As is shown by
As is shown in
As is shown by
Describing the outer body 622, starting from the mounting surface 626 and extending to the left, a first step of one of the wings 628 begins with a first step portion 636. The first step portion 636 extends angularly from the mounting surface 626. In accordance with the fifth exemplary embodiment of the invention, the first step portion 636 meets the mounting surface 626 at an approximately one hundred ninety degree angle.
As is shown by
As is shown in
As is shown by
It should be emphasized that the above-described embodiments of the present invention are merely possible examples of implementations, merely set forth for a clear understanding of the principles of the invention. Many variations and modifications may be made to the above-described embodiments of the invention without departing substantially from the spirit and principles of the invention. All such modifications and variations are intended to be included herein within the scope of this disclosure and the present invention and protected by the following claims.
This application claims priority to U.S. Provisional Application entitled, SYSTEM AND METHOD FOR PROVIDING ANTENNA RADIATION PATTERN CONTROL,” having Ser. No. 11/169,467, filed Jun. 29, 2005, which is entirely incorporated herein by reference.
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Number | Date | Country | |
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20070139278 A1 | Jun 2007 | US |
Number | Date | Country | |
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Parent | 11169467 | Jun 2005 | US |
Child | 11675795 | US |