Patent Publication Number: US-2021167514-A1

Title: Lens arrays configurations for improved signal performance

Description:
This application claims the benefit of co-pending U.S. non-provisional application Ser. No. 16/178,540, filed Nov. 1, 2018, which claims priority to U.S. non-provisional application Ser. No. 15/230,140, filed Aug. 5, 2016, which claims priority to U.S. provisional application No. 62/201,472 filed Aug. 5, 2015. This and all other referenced extrinsic materials are incorporated herein by reference in their entirety. Where a definition or use of a term in a reference that is incorporated by reference is inconsistent or contrary to the definition of that term provided herein, the definition of that term provided herein is deemed to be controlling. 
    
    
     FIELD OF THE INVENTION 
     The field of the invention is radio frequency antenna technology. 
     BACKGROUND 
     The following description includes information that may be useful in understanding the present invention. It is not an admission that any of the information provided herein is prior art or relevant to the presently claimed invention, or that any publication specifically or implicitly referenced is prior art. 
     Radio and microwave frequencies are widely used in wireless communication. Antennae utilized in receiving and sending such signals are often used in conjunction with a reflector (e.g., a parabolic reflector) that serves to focus electromagnetic energy in the desired spectral range on a feed that is positioned at the focal point of the reflector and is in communication with a receiver or transmitter. Such an arrangement, however, requires repositioning or aiming of the reflector in order to direct it towards different sources. 
     As an alternative to the use of a reflector, a lens capable of focusing radio frequency (RF) or microwave frequencies can be used. One suitable lens is a Luneburg lens, a spherically (or substantially spherical) symmetrical lens with a refractive index gradient that decreases from the center to the surface of the sphere. Electromagnetic energy traveling through such a lens necessarily takes the path that it can traverse in the least amount of time. In a classical Luneburg lens the gradient of refractive index is selected so that a focal point for electromagnetic energy impinging across a portion of the sphere is located on the opposing surface of the sphere. Some variations of the Luneburg lens are configured to place the focal point slightly beyond the opposing surface of the sphere in order to accommodate certain feed designs (such as a feed horn). The use of a Luneburg lens permits movement changing the direction of observation or transmission by simply moving the feed about the surface of the lens. In some designs, multiple feeds are arranged on or about the lens in order to permit gathering radio or microwave energy from a number of directions simultaneously without the need to move either the lens or the feeds. For example, a multi-beam station based on a single Luneburg lens can cover 120° in azimuth and thus support multiple beams. In a typical installation, a 1.8 meter spherical Luneburg antenna can support  12  beams having a 10° beam width at 10 dB separation for frequencies of 1.7 to 2.7 GHz. Increasing capacity beyond this can be accomplished by decreasing the beam width along the azimuth plane, however this restricts the utility of the device. An alternative is to increase the size of the Luneburg lens, however this approach rapidly encounters issues with the manufacturability of large lenses and the practical issues introduced by the size and weight of the larger lens. 
     One solution to this problem is to provide multiple lenses, where each lens is equipped with a single feed and where individual feeds are oriented towards different directions. In order to minimize space requirements such lens arrays are typically arranged on a plane in a linear fashion. Unfortunately, such an arrangement greatly restricts the relative angles of reception/transmission of adjacent feeds due to intersection of the transmitted or received signal with a portion of an adjacent lens. For example, in a conventional horizontal arrangement beams with a beam orientation of greater than 30° in the azimuth plane will intersect adjacent lenses. Such antenna arrays are also subject to the generation of undesirable grating lobes as a result of rapid decreases in field amplitudes between adjacent lenses. 
     Thus, there is still a need for a simple and effective device for providing accessible foci for radio and/or microwave frequencies from multiple directions 
     All publications herein are incorporated by reference to the same extent as if each individual publication or patent application were specifically and individually indicated to be incorporated by reference. Where a definition or use of a term in an incorporated reference is inconsistent or contrary to the definition of that term provided herein, the definition of that term provided herein applies and the definition of that term in the reference does not apply. 
     SUMMARY OF THE INVENTION 
     The inventive subject matter provides apparatus, systems and methods in which two or more spherical lenses are each associated with individual feed elements, and in which the spherical lenses are arranged in an array in an offset fashion such that electromagnetic energy focused by a first lens onto a first feed element does not intersect a second lens of the array. Grating lobes can be minimized in such arrangements by orienting radiating feeds towards the center of the lens array. 
     In another aspect of the inventive subject matter, the feed elements in a spherical lens elements array are tilted in a way such that the amplitude of the combined RF signals generated collectively by the feed elements in the array has minimal dips across the array. 
     Various objects, features, aspects and advantages of the inventive subject matter will become more apparent from the following detailed description of preferred embodiments, along with the accompanying drawing figures in which like numerals represent like components. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  illustrates a top view of a conventional lens array arrangement. 
         FIG. 2  illustrates a side view of the conventional lens array arrangement. 
         FIG. 3  illustrates a side view of a lens array arrangement of some embodiments that reduce impingement. 
         FIG. 4  illustrates a side view of another lens array arrangement of some embodiments that reduce impingement. 
         FIG. 5  illustrates a side view of yet another lens array arrangement of some embodiments that reduce impingement. 
         FIG. 6  illustrates a side view of yet another lens array arrangement of some embodiments that reduce impingement. 
         FIG. 7  illustrates a side view of yet another lens array arrangement of some embodiments that reduce impingement. 
         FIG. 8  illustrates a side view of a conventional lens array configuration 
         FIG. 9  illustrates a side view of a lens array configuration that provides improved overall signal pattern. 
         FIG. 10  illustrate a side view of another lens array configuration that provides improved overall signal pattern. 
         FIG. 11  illustrate a side view of another lens array configuration that provides improved overall signal pattern. 
     
    
    
     DETAILED DESCRIPTION 
     Throughout the following discussion, numerous references will be made regarding servers, services, interfaces, engines, modules, clients, peers, portals, platforms, or other systems formed from computing devices. It should be appreciated that the use of such terms is deemed to represent one or more computing devices having at least one processor (e.g., ASIC, FPGA, DSP, x86, ARM, ColdFire, GPU, multi-core processors, etc.) configured to execute software instructions stored on a computer readable tangible, non-transitory medium (e.g., hard drive, solid state drive, RAM, flash, ROM, etc.). For example, a server can include one or more computers operating as a web server, database server, or other type of computer server in a manner to fulfill described roles, responsibilities, or functions. One should further appreciate the disclosed computer-based algorithms, processes, methods, or other types of instruction sets can be embodied as a computer program product comprising a non-transitory, tangible computer readable media storing the instructions that cause a processor to execute the disclosed steps. The various servers, systems, databases, or interfaces can exchange data using standardized protocols or algorithms, possibly based on HTTP, HTTPS, AES, public-private key exchanges, web service APIs, known financial transaction protocols, or other electronic information exchanging methods. Data exchanges can be conducted over a packet-switched network, a circuit-switched network, the Internet, LAN, WAN, VPN, or other type of network. 
     As used in the description herein and throughout the claims that follow, when a system, engine, or a module is described as configured to perform a set of functions, the meaning of “configured to” or “programmed to” is defined as one or more processors being programmed by a set of software instructions to perform the set of functions. 
     The following discussion provides example embodiments of the inventive subject matter. Although each embodiment represents a single combination of inventive elements, the inventive subject matter is considered to include all possible combinations of the disclosed elements. Thus if one embodiment comprises elements A, B, and C, and a second embodiment comprises elements B and D, then the inventive subject matter is also considered to include other remaining combinations of A, B, C, or D, even if not explicitly disclosed. 
     As used herein, and unless the context dictates otherwise, the term “coupled to” is intended to include both direct coupling (in which two elements that are coupled to each other contact each other) and indirect coupling (in which at least one additional element is located between the two elements). Therefore, the terms “coupled to” and “coupled with” are used synonymously. 
     In some embodiments, the numbers expressing quantities of ingredients, properties such as concentration, reaction conditions, and so forth, used to describe and claim certain embodiments of the inventive subject matter are to be understood as being modified in some instances by the term “about.” Accordingly, in some embodiments, the numerical parameters set forth in the written description and attached claims are approximations that can vary depending upon the desired properties sought to be obtained by a particular embodiment. In some embodiments, the numerical parameters should be construed in light of the number of reported significant digits and by applying ordinary rounding techniques. Notwithstanding that the numerical ranges and parameters setting forth the broad scope of some embodiments of the inventive subject matter are approximations, the numerical values set forth in the specific examples are reported as precisely as practicable. The numerical values presented in some embodiments of the inventive subject matter may contain certain errors necessarily resulting from the standard deviation found in their respective testing measurements. 
     As used in the description herein and throughout the claims that follow, the meaning of “a,” “an,” and “the” includes plural reference unless the context clearly dictates otherwise. Also, as used in the description herein, the meaning of “in” includes “in” and “on” unless the context clearly dictates otherwise. 
     Unless the context dictates the contrary, all ranges set forth herein should be interpreted as being inclusive of their endpoints and open-ended ranges should be interpreted to include only commercially practical values. The recitation of ranges of values herein is merely intended to serve as a shorthand method of referring individually to each separate value falling within the range. Unless otherwise indicated herein, each individual value within a range is incorporated into the specification as if it were individually recited herein. Similarly, all lists of values should be considered as inclusive of intermediate values unless the context indicates the contrary. 
     All methods described herein can be performed in any suitable order unless otherwise indicated herein or otherwise clearly contradicted by context. The use of any and all examples, or exemplary language (e.g. “such as”) provided with respect to certain embodiments herein is intended merely to better illuminate the inventive subject matter and does not pose a limitation on the scope of the inventive subject matter otherwise claimed. No language in the specification should be construed as indicating any non-claimed element essential to the practice of the inventive subject matter. 
     Groupings of alternative elements or embodiments of the inventive subject matter disclosed herein are not to be construed as limitations. Each group member can be referred to and claimed individually or in any combination with other members of the group or other elements found herein. One or more members of a group can be included in, or deleted from, a group for reasons of convenience and/or patentability. When any such inclusion or deletion occurs, the specification is herein deemed to contain the group as modified thus fulfilling the written description of all Markush groups used in the appended claims. 
     In one aspect of the inventive subject matter, a lens array arrangement that includes multiple spherical lenses is provided to achieve improved signal performance and reduce signal interferences between adjacent lenses is provided. The lens array includes two sub arrays of lenses. The lenses in the first sub array are aligned along a first plane, while the lenses in the second sub array are aligned along a second plane that is parallel to the first plane, but having a perpendicular offset from the first plane. Each lens in the second sub array is disposed in between two adjacent lenses in the first sub array, such that adjacent lenses in the lens array are not aligned on the same plane. This arrangement of lenses in the array has the effect of reducing signal interferences and impingement between adjacent lens elements. 
     A spherical lens is a lens with an exterior surface having a shape of (or substantially having a shape of) a sphere. As defined herein, a lens with a surface that substantially conform to the shape of a sphere means at least 50% (preferably at least 80%, and even more preferably at least 90%) of the surface area conforms to the shape of a sphere. Examples of spherical lenses include a spherical-shell lens, the Luneburg lens, drum-shaped lens (a sphere with the top and bottom portions cut off and flattened), etc. The spherical lens can include only one layer of dielectric material, or multiple layers of dielectric material. A conventional Luneburg lens is a spherically symmetric lens that has multiple layers inside the sphere with varying indices of refraction. 
     In some embodiments, the lens array includes multiple lens elements. Each lens element includes a spherical lens and at least one feed element. The feed element is an electronic device for emitting RF signals, detecting RF signals, or both. In some embodiments, the feed element is disposed near the surface of the spherical lens (e.g., within 5 inches, preferably within 2 inches of the surface of the lens). Preferably, each lens element also includes a mechanism for moving the feed element along the surface of the lens in order to adjust the angles and direction in which the feed element emits/receives the RF signals. Details of this mechanism for moving the feed elements can be found in a co-owned U.S. patent application Ser. No. 14/958,607, titled “Spherical Lens Array Based Multi-Beam Antennae,” filed Dec. 3, 2015, which is incorporated in its entirety herein by reference. 
       FIG. 1  illustrates a top view of a conventional arrangement of a lens array  100 . The lens array  100  is shown to include two lens elements  105  and  110  adjacent to each other, however, more lens elements can be included in this lens array  100 . Each lens element includes a spherical lens and a feed element. For example, the lens element  105  includes a spherical lens  115  and a feed element  125 , and the lens element  110  includes a spherical lens  120  and a feed element  130 . As shown, the lens elements  105  and  110  are aligned along a virtual plane  135 . In some embodiments, the virtual plane  135  is parallel to the ground on top of which the lens array  100  is disposed. 
     The feed elements  125  and  130  are configured to emit and/or receive RF signals via the lenses  115  and  120 . When the feed elements  125  and  130  are positioned along the surface of the lenses  115  and  120  to emit RF signals having a major axis that is perpendicular to the plane  135  (e.g., at positions  145  and  150 ), the signals emitted by the feed elements  125  and  130  will be in-phase, and do not cause interference or impingement with each other. As defined herein, the major axis of an RF signal refers to the axis of an ellipse representing amplitude of the RF signal. 
     However, when the feed elements  125  and  130  are positioned along the surface of the lenses  115  and  120  to emit RF signals having a major axis that is not perpendicular to the plane  135  (e.g., at positions  165  and  170 ), a portion (e.g., the portion of the signals within the area  140 ) of the RF signal emitted by the feed element  125  would impinge on the RF signal emitted by the feed element  130 . The impingement causes reduction in quality of the signals being transmitted by the lens array, resulting in undesirable distortion and defocusing in that portion of the signal. Similarly, the RF signal emitted by the feed element  130  would impinge on the RF signal emitted by the feed element  125  when the feed elements  125  and  140  are at positions  155  and  160 . 
       FIG. 2  illustrates a side view of the lens array  100  that includes the lens elements  105  and  110 . The lens elements  105  and  110  are arranged on the plane  135 . 
       FIG. 3  illustrates a side view of a lens array  300  that is arranged according to some embodiments of the inventive subject matter. The lens array  300  includes lens elements  305  and,  310 . Each lens element includes a spherical lens and a feed element. For example, the lens element  305  includes a spherical lens  315  and a feed element  325 , and the lens element  310  includes a spherical lens  320  and a feed element  330 . 
     As shown, the lens element  305  is arranged on a virtual plane  335  while the lens element  310  is arranged on a virtual plane  340 . The virtual planes  335  and  340  are perpendicular to the drawing sheet. The virtual planes  335  and  340  are parallel to each other (and in some embodiments also parallel to the ground on top of which the lens array  300  is disposed) while having an offset  360  in a direction that is perpendicular to the planes  335  and  340 . In some embodiments, the offset  360  between the planes  335  and  340  is at least 50% of the height of the spherical lenses  315  and  320 . Preferably, the offset  360  between the planes  335  and  340  is at least 60% (even more preferably at least 70%) of the height of the spherical lenses  315  and  320 . Preferably, the offset  360  is less than 100% of the height of the spherical lenses  315  and  320 . As defined herein, the height of a spherical lens is calculated along a dimension of the spherical lens that is perpendicular to the planes  335  and  340 . In some embodiments, the lens elements  305  and  310  are also arranged on another plane that is perpendicular to the virtual planes  335  and  340  (parallel to the drawing sheet). 
     The vertical offset of adjacent lens elements in the lens array  300  has the effect of eliminating entirely or at least reducing impingement of the signals received by or transmitted from the adjacent lens elements. This arrangement advantageously reduces or eliminates distortion, loss of focus, and absorption of such signals by the adjacent lens without increasing the size or weight of individual lens elements. 
     It is conceived that the arrangement of lens array  300  can be extended to form a chessboard pattern.  FIG. 4  illustrates a side view of a lens array  400  that is arranged according to this chessboard pattern. The lens array  400  includes lens elements  405  and,  410 , and  415 . Each lens element includes a spherical lens and a feed element. For example, the lens element  405  includes a spherical lens  420  and a feed element  435 , the lens element  410  includes a spherical lens  425  and a feed element  440 , and the lens element  415  includes a spherical lens  430  and a feed element  445 . 
     As shown, the lens elements  405  and  415  are arranged on a virtual plane  450  while the lens element  410  is arranged on a virtual plane  455 . The virtual planes  450  and  455  are perpendicular to the drawing sheet. The lens elements  405  and  415  forms a sub-array, while the lens element  410  (can have additional lens element that is not shown in this figure) forms another sub-array. The planes  450  and  455  are parallel to each other while having an offset  460  in a direction that is perpendicular to the planes  450  and  455 . In some embodiments, the offset  460  between the planes  450  and  455  is at least 50% of the height of the spherical lenses  420 ,  425 , and  430 . Preferably, the offset  460  between the planes  450  and  455  is at least 60% (even more preferably at least 70%) of the height of the spherical lenses  420 ,  425 , and  430 . In some embodiments, the lens elements  405 ,  410 , and  415  are also arranged on another virtual plane that is perpendicular to the planes  450  and  455  (parallel to the drawing sheet). 
     The lens element  410  that is arranged on the plane  455  is disposed in between the lens elements  405  and  415 . Specifically, a portion of the spherical lens  425  of the lens element  410  is disposed within the space (gap) in between the lens elements  405  and  415 . In some embodiments, the space between the adjacent lens elements within a sub array (e.g., the lens elements  405  and  415 ) is less than the width of a spherical lens (e.g., spherical lenses  420 ,  425 , and  430 ). As defined herein, the width of a lens is measured along a dimension of the spherical lens that is parallel to the virtual planes  450  and  455 . 
     Although the lens array  400  shown in  FIG. 4  includes one lens element  410  that is arranged on top of two lens elements  405  and  415 , it is contemplated that the lens element  410  can also be arranged below the lens elements  405  and  415  and provide the same benefits. That is, the virtual plane  455  is parallel but below the virtual plane  450  with the same offset  460 . 
     The vertical offset of adjacent lens elements in this arrangement relative to the azimuth plane (horizontal plane that is parallel to the ground) avoids mutual impingement of the signals received by or transmitted from the lens/feed element units adjacent to each other. At the same time, the space provided between the coplanar lens/feed element units prevents impingement between these lens/feed element units. 
     It should be appreciated that the basic unit arrangement shown in  FIG. 4  can be propagated horizontally, providing a first sub-array of lens elements on a first virtual plane and a second sub-array of lens elements on a second virtual plane having a vertical offset to the first virtual plane.  FIG. 5  illustrates a side view of a lens array  500  that is arranged under this approach. The lens array  500  includes a first sub-array of lens elements  505  that are arranged on a virtual plane  515 , and a second sub-array of lens elements  510  that are arranged on a virtual plane  520  having a vertical offset  525 . The virtual planes  515  and  520  are perpendicular to the drawing sheet. As shown, each of the lens elements in the sub-array  510  is disposed in between two adjacent lens elements in the sub-array  505 . Furthermore, each pair of adjacent lens elements in the first sub-array  505  has a space offset between each other that is parallel to the plane  515 . Similarly, each pair of adjacent lens elements in the second sub-array  510  also has a space offset between each other that is parallel to the plane  520 . In some embodiments, the lenses in the lens array  500  are also arranged on another virtual plane that is perpendicular to the virtual planes  515  and  520  (parallel to the drawing sheet). 
     It is also appreciated that the basic unit arrangement shown in  FIG. 4  can be propagated vertically.  FIG. 6  illustrates a side view of a lens array  600  that is arranged under this approach. The lens array  600  includes a vertical array of the basic unit arrangement shown in  FIG. 4 . As shown, the lens array  600  includes basic units  605 ,  610 ,  615 , and  620 . Each of the basic units  605 ,  610 ,  615 , and  620  includes three lens elements arranged substantially the same way as the lens array  400  in  FIG. 4 . 
     Although the lens array  600  shown in  FIG. 6  includes four basic units of lens elements, it is contemplated that a lens array can include more than four or less than four of these basic units of lens elements without departing from the inventive concept. 
     Alternatively, the basic unit arrangement shown in  FIG. 4  can be propagated both horizontally and vertically to generate a two dimensional arrays resembling a chess board or hexagonal array. Such an arrangement advantageously provides a relatively compact antenna/feed element array without requiring special manufacturing methods and/or materials.  FIG. 7  illustrates a side view of a lens array  700  arranged under this approach. The lens array  700  includes a two-dimensional array of the basic units shown in  FIG. 4 . In other words, the lens array  700  includes multiple sub-arrays of lens elements, each sub-array of lens elements include lens elements that are arranged on a distinct virtual plane. In this example, the lens array  700  includes eight sub-arrays of lens elements  705 ,  710 ,  715 ,  720 ,  725 ,  730 ,  735 , and  740 . 
     The virtual planes of each pair of adjacent sub-array of lens elements have a vertical offset that is substantially similar to the offset  460  in  FIG. 4 . Each pair of adjacent lens elements in a sub-array also has a horizontal spacing that is similar to the spacing between lens elements  405  and  415 . 
     In another aspect of the inventive subject matter, a lens array with the two end (most outward) lens elements in the array having feed elements angled toward each other is presented. It is noted that arrays of lens/feed element units tend to develop unwanted grating lobes, represented by relatively large drops in amplitude between adjacent lenses. This phenomenon is illustrated in  FIG. 8 , which depicts a conventional arrangement of lenses and feed elements. 
       FIG. 8  illustrates a top view of a pair of adjacent lens elements  805  and  810 . The pair of adjacent lens elements are aligned along an axis  802 . Each lens elements includes a spherical lens and a feed element. For example, the lens element  805  includes a spherical lens  815  and a feed element  825 , and the lens element  810  includes a spherical lens  820  and a feed element  830 . Each of the feed elements  825  and  830  is configured to generate an RF signal having amplitude. For example,  FIG. 8  shows amplitude  835  of an RF signal generated by the feed element  825  through the spherical lens  815 , and amplitude  840  of an RF signal generated by the feed element  830  through the spherical lens  820 . The amplitudes  835  and  840  each has a major axis representing a direction of the corresponding amplitude. In this example, the amplitude  835  has a major axis  845  that is perpendicular to the axis  802 , and the amplitude  840  also has a major axis  850  that is perpendicular to the axis  802 , as the feed elements  825  and  830  are configured to transmit the RF signals in the same direction perpendicular to the axis  802  along which the lens elements  805  and  810  are aligned. As the amplitude of the RF signal from the lens elements  805  and  810  collectively can be measured by a sum of the amplitude from the RF signals generated by individual lens elements  805  and  810 , it can be seen that the combined amplitude (i.e., power) of the RF signal suffers a dramatic dip in the center (i.e., in between the two lens elements  805  and  810 ), which is undesirable. 
       FIG. 9  illustrates a configuration of lens elements  900  that would alleviate the amplitude dip issue illustrated in  FIG. 8 . The lens elements configuration  900  includes two lens elements  905  and  910 . The lens elements  905  and  910  are aligned along an axis  902 . Each lens element has a spherical lens and a feed element. In this example, the lens element  905  has a spherical lens  915  and a feed element  925 , and the lens element  910  has a spherical lens  920  and a feed element  930 . The configuration  900  is very similar to the lens configuration shown in  FIG. 8 , the two lens elements  905  and  910  are adjacent to (very close to or even in contact with) each other. The feed elements  925  and  930  are configured to transmit RF signals in a direction that is perpendicular to the axis  902 . Similar to the feed elements  825  and  830 , the feed elements  925  and  930  are configured to generate RF signals having amplitudes. In this example, the feed element  925  is configured to generate RF signals having amplitude  935  through the spherical lens  915 , and the feed element  930  is configured to generate RF signals having amplitude  940  through the spherical lens  920 . The amplitudes  935  and  940  each has a major axis representing a direction of the corresponding amplitude. The amplitude  935  has a major axis  945  and the amplitude  940  has a major axis  950 . 
     In order to alleviate the amplitude dip, the feed elements  925  and  930  are angled toward each other such that the major axes  945  and  950  are no longer perpendicular to the axis  902 . Specifically, the major axes  945  and  950  are not perpendicular to the axis  902 . Instead, each one of the major axes  945  and  950  forms an angle with respect to the axis  902 . As shown, the major axis  945  forms an angle  955  with respect to the axis  902  while the major axis  950  forms an angle  960  with respect to the axis  902 . In some embodiments, the feed elements  925  and  930  are oriented such that the angle  955  is substantially (e.g., at least 90%, at least 95%, etc.) the same as the angle  960 , but in the opposite direction. In other words, the major axes  945  and  950  converge in the direction of the RF signal amplitudes. Preferably, the feed elements  925  and  930  are oriented in a way such that the angles  955  and  960  are between 5° and 30°, inclusively. Even more preferably the feed elements  925  and  930  are oriented in a way such that the angles  955  and  960  are between 10° and 20°, inclusively. 
       FIG. 9  illustrates a lens elements configuration that involves two lens elements. It is contemplated that this approach of lens elements configuration can also be applied to an array of lens elements having more than two lens elements. When the array of lens elements has more than two lens elements, the two outside lens elements (end lens elements) in the array would have feed elements tilted (angled or oriented) toward each other. In other words the two end lens elements are tilted in a way that produce RF signals with a major axis forming an angle other than right angle with respect to the axis along which the array of lens elements are aligned. 
     When the lens elements array has an odd number of lens elements, the feed element of the center lens element is oriented in its normal operational orientation to produce RF signals having a major axis that is perpendicular to the axis along which the lens elements in the array are aligned.  FIG. 10  illustrates an example lens elements array  1000  according to this configuration. In this example, the lens elements array  100  has three lens elements: lens elements  1005 ,  1010 , and  1015 . The lens elements  1005 ,  1010 , and  1015  are aligned along an axis  1002 . Each lens element has a spherical lens and a feed element. In this example, the lens element  1005  has a spherical lens  1020  and a feed element  1035 , the lens element  1010  has a spherical lens  1025  and a feed element  1040 , and the lens element  1015  has a spherical lens  1030  and a feed element  1045 . The end lens elements  1005  and  1015  have the same configuration as the lens elements  905  and  910 , where the feed elements  1035  and  1045  are oriented (tilted or angled) toward each other such that the RF signals have major axes that are not perpendicular with respect to the axis  1002 . The major axes instead form an angle with the  1002 , and converge with each other in the direction of the RF signals amplitude. 
     When the lens elements array has more than three lens elements, the feed elements of the lens elements other than the center element (if the array has an odd number of lens elements) are also oriented such that their respective major axes converge in the direction toward the center of the array.  FIG. 11  illustrates an example lens elements array  1100  according to this lens elements configuration approach. The lens elements array  1100  has four lens elements: lens elements  1105 ,  1110 ,  1115 , and  1120 . The lens elements  1105 ,  1110 ,  1115 , and  1120  are aligned along an axis  1102 . Each lens element has a spherical lens and a feed element. In this example, the lens element  1105  has a spherical lens  1025  and a feed element  1045 , the lens element  1110  has a spherical lens  1030  and a feed element  1050 , the lens element  1115  has a spherical lens  1035  and a feed element  1155 , and the lens element  1120  has a spherical lens  1040  and a feed element  1160 . Since the lens elements array  1100  has an even number of lens elements, there is no center lens element in this array  1100 . As shown, the feed element of each lens element in the array  1100  is oriented (tilted or angled) in such a way that the major axis of the RF signals generated by the feed element form an angle other than right angle with respect to the axis  1102  (not perpendicular to axis  1102 ). Specifically, the major axes converge with each other in the direction of the RF signals amplitude. 
     Furthermore, it is contemplated that the feed elements of the lens elements that are located farther away from the center of the lens array  1100  (e.g., the lens elements  1105  and  1120 ) are oriented such that the major axes form a smaller angle with respect to the axis  1102  (i.e., the feed elements are more tilted toward each other) than the feed elements of the lens elements that are more toward the inside of the lens array  1100  (e.g., the lens elements  1110  and  1115 ). In other words, the farther away the lens elements are located from the center of the array  1100 , the more tiled are the feed elements. Similarly, the closer the lens elements are located from the center of the array  1100 , the less tilted are the feed elements. Similar to the configuration in  FIG. 9 , each lens element is paired up with another lens element that has the same distance from the center of the lens array  1100 . The feed elements in each pair should be tiled substantially at the same angle. In this example, the feed elements  1145  and  1160  are tilted substantially at the same angle, while the feed elements  1150  and  1155  are tilted substantially at the same angle. Although  FIG. 11  shows only four lens elements, more lens elements can be included in the lens elements array  1100  under this approach. 
     It is important to note that while these feed elements are tiled (angled or oriented) with respect to the axis along which the lens elements are aligned in the array, the locations of the feed elements remained the same, which is parallel to the axis. The feed elements are still located in the positions along the surfaces of the spherical lenses to generate RF signals in the direction that is perpendicular to the axis, and as such, the feed elements are not relocated to another position along the surface of the spherical lenses to achieve this result. 
     It should be apparent to those skilled in the art that many more modifications besides those already described are possible without departing from the inventive concepts herein. The inventive subject matter, therefore, is not to be restricted except in the spirit of the appended claims. Moreover, in interpreting both the specification and the claims, all terms should be interpreted in the broadest possible manner consistent with the context. In particular, the terms “comprises” and “comprising” should be interpreted as referring to elements, components, or steps in a non-exclusive manner, indicating that the referenced elements, components, or steps may be present, or utilized, or combined with other elements, components, or steps that are not expressly referenced. Where the specification claims refers to at least one of something selected from the group consisting of A, B, C . . . and N, the text should be interpreted as requiring only one element from the group, not A plus N, or B plus N, etc.