Patent Grant
12166283
The present disclosure relates to communication systems and, in particular, to multi-band base station antennas.
Base station antennas for wireless communication systems are used to transmit Radio Frequency (“RF”) signals to, and receive RF signals from, fixed and mobile users of a cellular communications service. Base station antennas often include a linear array or a two-dimensional array of radiating elements, such as dipole, or crossed dipole, radiating elements.
Example base station antennas are discussed in International Publication No. WO 2017/165512 to Bisiules and U.S. patent application Ser. No. 15/921,694 to Bisiules et al., the disclosures of which are hereby incorporated herein by reference in their entireties. Though it may be advantageous to incorporate multiple arrays of radiating elements in a single base station antenna, wind loading and other considerations often limit the number of arrays of radiating elements that can be included in a base station antenna.
A base station antenna, according to some embodiments herein, may include first and second vertical columns of low-band radiating elements configured to transmit RF signals in a first frequency band. Moreover, the base station antenna may include eight vertical columns of high-band radiating elements configured to transmit RF signals in a second frequency band that is higher than the first frequency band. A first vertical column among the eight vertical columns of high-band radiating elements may be between the first and second vertical columns of low-band radiating elements. A second vertical column among the eight vertical columns of high-band radiating elements may include fewer high-band radiating elements than the first vertical column of high-band radiating elements.
In some embodiments, the first and second vertical columns of high-band radiating elements may be inner and outer columns, respectively. Feed points of the outer column of high-band radiating elements may be aligned in a vertical direction with feed points of the second vertical column of low-band radiating elements. Additionally or alternatively, the outer column of high-band radiating elements may be a first outer column of high-band radiating elements, a third vertical column among the eight vertical columns of high-band radiating elements may be a second outer column of high-band radiating elements, and the first and second vertical columns of low-band radiating elements may be first and second outer columns, respectively, of low-band radiating elements. Moreover, the first and second outer columns of low-band radiating elements may be between the first and second outer columns of high-band radiating elements.
According to some embodiments, feed points of the first vertical column of high-band radiating elements may be staggered relative to feed points of the second vertical column of high-band radiating elements. Additionally or alternatively, the base station antenna may include a feeding board having the first and second vertical columns of low-band radiating elements and the first and second vertical columns of high-band radiating elements mounted thereon.
In some embodiments, a third vertical column among the eight vertical columns of high-band radiating elements may be between the first and second vertical columns of low-band radiating elements. Feed points of the first vertical column of high-band radiating elements may be horizontally spaced apart from feed points of the third vertical column of high-band radiating elements by a first distance. Moreover, feed points of the first vertical column of low-band radiating elements may be horizontally spaced apart from feed points of the second vertical column of low-band radiating elements by a second distance that is substantially an integer multiple of the first distance.
According to some embodiments, feed points of the first vertical column of high-band radiating elements may be vertically spaced apart from each other by a first distance. Feed points of the second vertical column of low-band radiating elements may be vertically spaced apart from each other by a second distance that is substantially an integer multiple of the first distance. Moreover, the second vertical column of high-band radiating elements may include consecutive first, second, and third feed points, the first and second feed points may be vertically spaced apart from each other by the first distance, and the second and third feed points may be vertically spaced apart from each other by a third distance that is longer than the first distance and shorter than the second distance.
A base station antenna, according to some embodiments herein, may include a vertical column of low-band radiating elements configured to transmit RF signals in a first frequency band. Moreover, the base station antenna may include first, second, and third vertical columns of high-band radiating elements configured to transmit RF signals in a second frequency band that is higher than the first frequency band. The vertical column of low-band radiating elements may be between the first and second vertical columns of high-band radiating elements. The third vertical column of high-band radiating elements may include fewer high-band radiating elements than the first vertical column of high-band radiating elements.
In some embodiments, feed points of the third vertical column of high-band radiating elements may be aligned in a vertical direction with feed points of the vertical column of low-band radiating elements. Additionally or alternatively, the vertical column of low-band radiating elements may include a first vertical column of low-band radiating elements, and the base station antenna may include a second vertical column of low-band radiating elements that is between the first and second vertical columns of high-band radiating elements. Moreover, the first and second vertical columns of low-band radiating elements may be first and second outer columns, respectively, of low-band radiating elements. The first and second vertical columns of high-band radiating elements may be first and second outer columns, respectively, of high-band radiating elements.
According to some embodiments, the first and second vertical columns of high-band radiating elements may be first and second outer columns, respectively, of high-band radiating elements. Moreover, the vertical column of low-band radiating elements may be centered between the first and second outer columns of high-band radiating elements.
In some embodiments, the first and second vertical columns of high-band radiating elements may be first and second outer columns, respectively, of high-band radiating elements. Moreover, the vertical column of low-band radiating elements may be offset from a center between the first and second outer columns of high-band radiating elements.
According to some embodiments, the base station antenna may include a feeding board having the low-band radiating elements and the high-band radiating elements mounted on a surface thereof. Moreover, a dipole arm of one of the low-band radiating elements may overlap one of the high-band radiating elements in a direction that is perpendicular to the surface of the feeding board.
A base station antenna, according to some embodiments herein, may include one or more vertical columns of low-band radiating elements configured to transmit RF signals in a first frequency band. Moreover, the base station antenna may include five or more vertical columns of high-band radiating elements configured to transmit RF signals in a second frequency band that is higher than the first frequency band. The five or more vertical columns of high-band radiating elements may extend in parallel with the one or more vertical columns of low-band radiating elements in a vertical direction.
In some embodiments, consecutive first, second, and third vertical columns among the five or more vertical columns of high-band radiating elements may be non-staggered relative to each other. Additionally or alternatively, the station antenna may include a feeding board including the low-band radiating elements and the high-band radiating elements on a surface thereof. A dipole arm of one of the low-band radiating elements may overlap one of the high-band radiating elements in a direction that is perpendicular to the surface of the feeding board.
According to some embodiments, the five or more vertical columns of high-band radiating elements may include at least eight vertical columns of high-band radiating elements. Additionally or alternatively, first and second vertical columns among the five or more vertical columns of high-band radiating elements may include different first and second quantities, respectively, of high-band radiating elements.
In some embodiments, the one or more vertical columns of low-band radiating elements may include first and second vertical columns of low-band radiating elements, and feed points of the first vertical column of low-band radiating elements may be spaced apart from feed points of the second vertical column of low-band radiating elements in a horizontal direction by a distance of about 280 millimeters or less. Moreover, the distance may be a first distance, and feed points of a first vertical column among the five or more vertical columns of high-band radiating elements may be spaced apart from feed points of a consecutive second vertical column among the five or more vertical columns of high-band radiating elements in the horizontal direction by a second distance. The first distance may be substantially an integer multiple of the second distance. The feed points of the first vertical column among the five or more vertical columns of high-band radiating elements may be spaced apart from each other in the vertical direction by a third distance. The feed points of the second vertical column of low-band radiating elements may be spaced apart from each other in the vertical direction by a fourth distance that is substantially an integer multiple of the third distance.
Pursuant to embodiments of the present inventive concepts, base station antennas for wireless communication networks are provided. The enhanced-capacity capability of massive MIMO techniques for wireless communication networks makes it desirable to deploy massive MIMO antenna arrays into the existing wireless infrastructure. Frequency bands often considered for massive MIMO operation are in the 2490-2690 megahertz (MHz) and 3300-3800 MHz frequency bands. Yet wireless service providers are faced with the challenge of adding additional antennas and radio heads onto existing towers to provide massive MIMO service in these frequency bands. Some of the challenges may include the lack of availability of mounting space for an additional base station antenna array or the additional wind loading that these base station antenna arrays would add to an existing tower. Because massive MIMO antenna arrays often comprise a large number of antenna elements, often 64 to 256 elements, these arrays can be quite large in size. Additionally, wireless service providers may incur additional lease charges from tower or building owners when adding an additional base station antenna array. Moreover, in many markets, municipal zoning restrictions limit the quantity or height of base station antennas, thus limiting the ability to add massive MIMO base station antenna arrays to provide enhanced-capacity capability.
It may therefore be advantageous to integrate massive MIMO antenna capability in upper frequency bands into multi-band base station antennas. Existing base station antennas often have arrays of antenna elements covering multiple wireless bands from 694 to 2690 MHz. These arrays are often configured as multiple vertical columns of radiating elements, with each radiating element having dual-polarization capability to support MIMO operation in configurations up to 4T4R for 4G LTE.
To keep the overall size of a base station antenna as small as possible, cloaking techniques have been developed that allow low-band radiating elements operating in the 694 to 960 MHz range to appear electromagnetically transparent to mid-band radiating elements operating in the 1427-2690 MHz range. This allows some radiating elements of mid-band arrays to be placed behind (e.g., lower/underneath) the low-band radiating elements, thereby enabling a reduction in the overall size of the multi-band base station antenna.
A similar size optimization can be implemented in the integration of a 3.5 gigahertz (GHz) massive MIMO array into a multi-band base station antenna. The columns of low-band radiating elements are typically spaced by a distance of about 280 millimeters (mm) or less at their feed points (i.e., center-to-center spacing) due to the relatively large physical size of the low-band radiating elements. In light of the relatively large spacing between the low-band columns, it is possible to position an 8T8R high-band array of four columns of dual-polarized radiating elements between two low-band columns of radiating elements. The separation distance between the columns of the 3.5 GHz array may be in the range of about 39 mm to 40 mm, and the total width of the four-column high-band array may thus be about 160 mm, which may allow this high-band array to fit between the two low-band columns.
Various massive MIMO array configurations can provide significant performance improvement. For example, an 8T8R array can provide about 13% more capacity into a sector than a 4T4R array. An 16T16R array can provide about 82% more capacity into a sector than a 4T4R array. Though these comparisons depend upon multiple conditions and assumptions and are therefore variable, a 16T16R array can generally be expected to provide significantly higher capacity than an 8T8R array and therefore will likely be more desirable. Yet the eight columns of dual-polarized radiating elements at 3.5 GHz are horizontally spaced apart by about 280 mm between feed points of outer columns, thus inhibiting a 16T16R high-band array from fitting entirely between a low-band array having a horizontal feed-point spacing of about 280 mm within a multi-band base station antenna.
According to embodiments of the present inventive concepts, however, high-band and low-band arrays may be interleaved with each other. For example, a small percentage (e.g., 10% or fewer) of the radiating elements of the high-band array may be omitted/removed to provide space for the low-band radiating elements. As an example, a base station antenna may include one or more columns of low-band radiating elements interspersed with five or more (staggered or non-staggered) columns of high-band radiating elements, with one or more high-band columns having fewer high-band radiating elements than other high-band columns. Additionally or alternatively, (a) vertical and horizontal element spacings in both arrays may have common multiples, (b) the low-band radiating elements may be in locations that are electromagnetically transparent at high-band frequencies, and/or (c) the high-band radiating elements may be positioned behind the low-band radiating elements.
In some embodiments, a high-band array has eight columns of dual-polarized radiating elements, with twelve dual-polarized radiating elements in each column. Adjacent (i.e., consecutive) ones of the eight columns may be separated by 40 mm, and the outer first and eighth columns thus may be separated by 280 mm from center-to-center. The vertical spacing between high-band radiating elements may be 66 mm. The low-band array may have two columns of low-band radiating elements separated by 280 mm from center-to-center, and the vertical spacing between these elements may be 264 mm. By omitting/removing some non-adjacent (i.e., non-consecutive) elements in the outer columns of the high-band array and replacing these with low-band radiating elements that are part of the low-band array, the pattern and massive MIMO characteristics of the high-band array can be maintained with negligible impact. For example, the first, fifth, and ninth radiating elements of the outer left high-band column, and the fourth, eighth, and twelfth radiating elements of the outer right high-band column may be omitted/removed. As this is a staggered high-band array, the vertical element spacing may be 66 mm, which allows adequate space for replacement of these omitted/removed high-band radiating elements with low-band radiating elements.
The insertion of the low-band radiating elements at the locations of the omitted/removed high-band radiating elements provides an interleaved low-band and high-band array, which may be a sub-section of a larger low-band array. The entire low-band array may have two columns having ten radiating elements in each column. The high-band array may be interleaved among the eight lower radiating elements of the low-band array. Interleaving the high-band array with the low-band array by setting the vertical and horizontal spacings of the radiating elements of both arrays to have common multiples, omitting/removing a small percentage of the high-band array radiating elements, placing low-band radiating elements in locations that are electromagnetically transparent at high-band frequencies, and/or positioning the high-band radiating elements behind the low-band radiating elements may allow the high-band array to be implemented within the envelope of the low-band array, thereby avoiding the need to implement the high-band array as a separate base station antenna. This meets the objective of enabling massive MIMO operation in high-bands using larger MIMO orders, such as 16T16R, without requiring installation of additional base station antennas on base station towers.
Example embodiments of the present inventive concepts will be described in greater detail with reference to the attached figures.
The base station antenna 100 includes a radome 110. In some embodiments, the base station antenna 100 further includes a top end cap 120 and/or a bottom end cap 130. For example, the radome 110, in combination with the top end cap 120, may comprise a single unit, which may be helpful for waterproofing the base station antenna 100. The bottom end cap 130 is usually a separate piece and may include a plurality of connectors 140 mounted therein.
In some embodiments, mounting brackets 150 may be provided on the rear (i.e., back) side of the radome 110. The mounting brackets 150 may be used to mount the base station antenna 100 onto an antenna mount that is on, for example, an antenna tower. The base station antenna 100 is typically mounted in a vertical configuration (i.e., the long side of the base station antenna 100 extends along a vertical axis L with respect to Earth).
The low-band array 310 may extend in a vertical direction V from a lower portion of the antenna assembly 200 to an upper portion of the antenna assembly 200. The high-band array 510, by contrast, may be on the lower portion of the antenna assembly 200 and absent from the upper portion of the antenna assembly 200. For example, the high-band array 510 may be on only the lower 40% of the antenna assembly 200. In some cases, a second high-band array 510 may be added at the upper portion of the antenna assembly 200. Moreover, column spacing in the antenna assembly 200 may be common or overlapping.
The vertical direction V may be, or may be in parallel with, the longitudinal axis L (
As used herein, the term “outer column” (or “outer vertical column”) refers to a column that is not between, in the horizontal direction H, adjacent columns of that column type (e.g., high-band or low-band). The term “inner column” (or “inner vertical column”), by contrast, refers to a column that is between, in the horizontal direction H, adjacent columns of that column type. Also, the term “feed point” may refer to the center point of a radiating element.
The feed points 501 of the first vertical column 500-1C of high-band radiating elements 500 may be aligned (or substantially aligned) in the vertical direction V with feed points 301 of a first outer vertical column 300-1C of low-band radiating elements 300. Similarly, the feed points 501 of the eighth vertical column 500-8C of high-band radiating elements 500 may be aligned (or substantially aligned) in the vertical direction V with feed points 301 of a second outer vertical column 300-2C of low-band radiating elements 300. Accordingly, the feed points 301 of the first outer vertical column 300-1C of low-band radiating elements 300 may be spaced apart from the feed points 301 of the second outer vertical column 300-2C of low-band radiating elements 300 in the horizontal direction H by the same non-zero distance as the feed points 501 of the first and eighth vertical columns 500-1C and 500-8C of high-band radiating elements 500, such as by about 280 mm in the example embodiment of
Inner ones (i.e., six) of the eight vertical columns 500-1C through 500-8C of high-band radiating elements 500 may be between the feed points 301 of the first and second outer vertical columns 300-1C and 300-2C of low-band radiating elements 300 in the horizontal direction H. The outer vertical columns 500-1C, 500-8C may each include fewer high-band radiating elements 500 than the inner vertical columns 500-2C through 500-7C. For example, at least one of the outer vertical columns 500-1C, 500-8C may comprise a reduction of one, two, three or more high-band radiating elements 500 relative to at least one of the inner vertical columns 500-2C through 500-7C. As an example, the inner vertical columns 500-2C through 500-7C may each comprise twelve high-band radiating elements 500, and the outer vertical columns 500-1C, 500-8C may each comprise nine high-band radiating elements 500. Though twelve and nine are given as examples, the number of high-band radiating elements 500 in a vertical column can be any quantity from two to twenty or more.
By including fewer high-band radiating elements 500 in the outer vertical columns 500-1C, 500-8C, the high-band radiating elements 500 can be more efficiently integrated alongside the low-band radiating elements 300. For example, the space that is made available by including fewer high-band radiating elements 500 in the outer vertical columns 500-1C, 500-8C can be occupied by the low-band radiating elements 300, thus allowing the feed points 301 of the low-band radiating elements 300 to be aligned in the vertical direction V with the feed points 501 of the high-band radiating elements 500. In some embodiments, the low-band radiating elements 300 may alternate (i.e., be interleaved) with groups of the high-band radiating elements 500 in the vertical direction V. As an example, three of the high-band radiating elements 500 may be between each pair of the low-band radiating elements 300 in the vertical direction V.
The low-band radiating elements 300 may be configured to be electromagnetically transparent within the 3300-3800 MHz band, and thus may not significantly impact the radiation or reception behavior of the high-band array 510. Examples of radiating elements that are electromagnetically transparent to a different frequency band from that in which they are configured to transmit are discussed in Chinese Patent Application No. 201810971466.4, the disclosure of which is hereby incorporated herein by reference in its entirety.
One or more techniques for achieving electromagnetic transparency may be used for the low-band radiating elements 300. In some embodiments, a dipole arm 305 (
As shown in
Though
Moreover, a distance in the horizontal direction H between feed points 501 in consecutive columns of the high-band radiating elements 500 may be about 36-40 mm. As an example, a distance between a feed point 501 of the vertical column 500-1C and a feed point of the vertical column 500-2C in the horizontal direction H may be about 39-40 mm. For comparison, the distance shown in the horizontal direction H in
Each of the vertical columns 500-1C through 500-8C shown in
Alternatively, the spacing shown in
Though
Accordingly, as shown in
At least one of the first and second outer vertical columns 300-1C and 300-2C may be offset, in the horizontal direction H, from a center (e.g., a centered vertical axis) between the outer first and eighth vertical columns 500-1C and 500-8C. The vertical columns 300-1C and 300-2C may be staggered relative to each other or may be aligned with each other. In some embodiments, the feed points 301 of the first and second outer vertical columns 300-1C and 300-2C may be aligned in the vertical direction V with feed points 501 of the inner second and seventh vertical columns 500-2C and 500-7C, respectively. The inner second and seventh vertical columns 500-2C and 500-7C may also have fewer high-band radiating elements 500 than the outer first and eighth vertical columns 500-1C and 500-8C. Moreover, irrespective of whether any of the high-band radiating elements 500 extends in the horizontal direction H beyond the low-band radiating elements 300, at least one vertical column of high-band radiating elements 500 may be between, in the horizontal direction H, the two vertical columns 300-1C and 300-2C of the low-band radiating elements 300.
Referring to
Referring to
The non-staggered arrangement of the high-band radiating elements 500 as shown in
Irrespective of whether they are staggered or non-staggered, five or more vertical columns 500-1C through 500-8C of antenna 100 may extend in parallel with one or more vertical columns 300-1C/300-2C of low-band radiating elements 300 in the vertical direction V. Also, the five or more vertical columns 500-1C through 500-8C may, in some embodiments, comprise at least eight (e.g., 8, 9, 10, 11, 12, 13, 14, 15, or 16) vertical columns of high-band radiating elements 500.
In embodiments in which the five or more of the vertical columns 500-1C through 500-8C are non-staggered, at least one high-band radiating element 500 may be omitted to provide space for a respective low-band radiating element 300. For example,
Referring to
For simplicity of illustration, only four vertical columns of the high-band radiating elements 500 are shown in
Various mechanical and electronic components of the antenna 100 may be mounted in a chamber behind a back side of the reflector surface 214. The components may include, for example, phase shifters, remote electronic tilt units, mechanical linkages, a controller, diplexers, and the like. The reflector surface 214 may comprise a metallic surface that serves as a reflector and ground plane for the radiating elements 300, 400, 500 of the antenna 100. Herein, the reflector surface 214 may also be referred to as the reflector 214.
The radiating elements 300, 400, 500 may comprise dual-polarized radiating elements that are mounted to extend forwardly in the forward direction F from the reflector surface 214. As shown in
In
The low-band radiating elements 300 may be configured to transmit and receive signals in a frequency band comprising the 694-960 MHz frequency range or a portion thereof. The mid-band radiating elements 400 may be configured to transmit and receive signals in a frequency band comprising the 1427-2690 MHz frequency range or a portion thereof. The high-band radiating elements 500 may be configured to transmit and receive signals in a frequency band comprising the 3300-4200 MHz frequency range or a portion thereof.
The low-band linear arrays may or may not be configured to transmit and receive signals in the same portion of a low frequency band. For example, in some embodiments, the low-band radiating elements 300 in a first linear array may be configured to transmit and receive signals in the 700 MHz frequency band and the low-band radiating elements 300 in a second linear array may be configured to transmit and receive signals in the 800 MHz frequency band. Alternatively, the low-band radiating elements 300 in both the first and second linear arrays may be configured to transmit and receive signals in the 700 MHz (or 800 MHz) frequency band. The mid-band and high-band radiating elements 400, 500 in the different mid-band and high-band linear arrays may similarly have any suitable configuration.
As noted above, the low-band radiating elements 300 may be arranged as two low-band linear arrays of radiating elements. Each linear array may be used to form a pair of antenna beams, namely an antenna for each of the two polarizations at which the dual-polarized radiating elements are designed to transmit and receive RF signals. Each radiating element 300 in the first low-band array may be horizontally aligned in the horizontal direction H with a respective radiating element 300 in the second low-band array. Likewise, each radiating element 400 in the first mid-band array may be horizontally aligned with a respective radiating element 400 in the second mid-band array. In some embodiments, beamforming can be performed using all of the vertical columns 500-1C through 500-8C of the high-band radiating elements 500.
The radiating elements 300, 400, 500 may be mounted on one or more feeding (or “feed”) boards 204 (
The arrangements of the high-band radiating elements 500 and the low-band radiating elements 300 according to embodiments of the present inventive concepts may provide a number of advantages. These advantages include providing space for the low-band radiating elements 300 by eliminating one or more of the high-band radiating elements 500, such as in the positions 500-1X and 500-8X (
By eliminating only a small quantity of the high-band radiating elements 500, any impact on the high-band performance of an antenna 100 may not be significantly detrimental. As an example, quantization lobes resulting from the non-uniform spacing of the high-band radiating elements 500 may not be significant. Any loss in gain may also be too small to significantly reduce high-band performance.
As an alternative to eliminating some of the high-band radiating elements 500, spacing between the high-band radiating elements 500 may be decreased to provide room for the low-band radiating elements 300. Such decreased spacing, however, may introduce fit and feeding complications to an antenna 100.
Moreover, configuring the low-band radiating elements 300 to be electromagnetically transparent to frequencies of the high-band radiating elements 500 may help to facilitate the integration of the high-band radiating elements 500 alongside the low-band radiating elements 300. For example, one or more electromagnetic transparency techniques may be used to allow the high-band radiating elements 500 to be positioned behind (in the forward direction F) the low-band radiating elements 300.
The present inventive concepts have been described above with reference to the accompanying drawings. The present inventive concepts are not limited to the illustrated embodiments. Rather, these embodiments are intended to fully and completely disclose the present inventive concepts to those skilled in this art. In the drawings, like numbers refer to like elements throughout. Thicknesses and dimensions of some components may be exaggerated for clarity.
Spatially relative terms, such as “under,” “below,” “lower,” “over,” “upper,” “top,” “bottom,” 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. It will be understood that the spatially relative terms are 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 “under” or “beneath” other elements or features would then be oriented “over” the other elements or features. Thus, the example term “under” can encompass both an orientation of over and under. The device may be otherwise oriented (rotated 90 degrees or at other orientations) and the spatially relative descriptors used herein interpreted accordingly.
Herein, the terms “attached,” “connected,” “interconnected,” “contacting,” “mounted,” and the like can mean either direct or indirect attachment or contact between elements, unless stated otherwise.
Well-known functions or constructions may not be described in detail for brevity and/or clarity. As used herein the expression “and/or” includes any and all combinations of one or more of the associated listed items.
The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the present inventive concepts. As used herein, the singular forms “a,” “an,” and “the” are intended to include the plural forms as well, unless the context clearly indicates otherwise. It will be further understood that the terms “comprises,” “comprising,” “includes,” and/or “including” when used in this specification, specify the presence of stated features, operations, elements, and/or components, but do not preclude the presence or addition of one or more other features, operations, elements, components, and/or groups thereof.
The present application is a 35 U.S.C. § 371 national stage application of PCT International Application No. PCT/US2020/015288, filed Jan. 28, 2020, which itself claims priority to U.S. Provisional Patent Application No. 62/800,133, filed Feb. 1, 2019, the entire content of each of which is incorporated herein by reference.
| Filing Document | Filing Date | Country | Kind |
|---|---|---|---|
| PCT/US2020/015288 | 1/28/2020 | WO |
| Publishing Document | Publishing Date | Country | Kind |
|---|---|---|---|
| WO2020/159902 | 8/6/2020 | WO | A |
| Number | Name | Date | Kind |
|---|---|---|---|
| 6211841 | Smith et al. | Apr 2001 | B1 |
| 6583760 | Martek | Jun 2003 | B2 |
| 20090135078 | Lindmark et al. | May 2009 | A1 |
| 20110156986 | Baliarda et al. | Jun 2011 | A1 |
| 20140111396 | Hyjazie et al. | Apr 2014 | A1 |
| 20170310009 | Isik et al. | Oct 2017 | A1 |
| 20180145424 | Puente Baliarda et al. | May 2018 | A1 |
| 20180301801 | Hojjat et al. | Oct 2018 | A1 |
| 20180337443 | Bisiules et al. | Nov 2018 | A1 |
| Number | Date | Country |
|---|---|---|
| 110858679 | Mar 2020 | CN |
| 0962033 | Dec 1999 | EP |
| 2017165512 | Sep 2017 | WO |
| 2019052633 | Mar 2019 | WO |
| Entry |
|---|
| Extended European Search Report corresponding to European Application No. 20748874.3 (9 pages) (Jun. 29, 2022). |
| Notification of Transmittal of the International Search Report and the Written Opinion of the International Searching Authority, or the Declaration, in corresponding PCT Application No. PCT/US2020/015288 (Apr. 27, 2020). |
| Number | Date | Country | |
|---|---|---|---|
| 20210391655 A1 | Dec 2021 | US |
| Number | Date | Country | |
|---|---|---|---|
| 62800133 | Feb 2019 | US |
