The present disclosure relates to wireless communications, and in particular, to hybrid filter solutions.
The Third Generation Partnership Project (3GPP) has developed and is developing standards for Fourth Generation (4G) (also referred to as Long Term Evolution (LTE)) and Fifth Generation (5G) (also referred to as New Radio (NR)) wireless communication systems. Such systems provide, among other features, broadband communication between network nodes, such as base stations, and mobile wireless devices (WD), as well as communication between network nodes and between WDs. Sixth Generation (6G) wireless communication systems are also under development.
All of these standards, as well as other radio access technologies (RATs), contemplate transmission and reception in multiple frequency bands. Radio frequency (RF) transceivers at a radio base station may employ filters to filter signals to be transmitted by a radio transmitter of the transceiver as well as to filter signals that are received by a radio receiver of the transceiver. In particular, air cavity filters have high Q, where a high Q indicates that the air cavity filter has high frequency selectivity and energy storage capability. However, air cavity filters are large, heavy and expensive. In contrast to air cavity filters, ceramic wave guide filters (CWGF) are smaller, weigh less and are less expensive. However, ceramic wave guide filters have a lower Q than air cavity filters.
According to one proposal, an air cavity filter is employed for transmission and a CWGF is employed for reception. However, a problem remains how to efficiently combine these filters for frequency division duplex (FDD) applications, where transmission is at one frequency and reception is at another frequency. The air cavity filter is much different in design and operation than the CWGF. In particular, the air cavity filter and the CWGF are different in size, materials, and location of manufacture.
In one attempt to combine these two types of filters, a printed circuit board (PCB) has transmission lines that connect to the CWGF. The PCB is mounted close to the air cavity filter and connected to the air cavity filter by a cable. The two filters are ideally matched at the antenna port by adjusting the length of the cable according to a T-junction matching principle. Problems with this approach include additional loss due at least in part to difficulty in selecting the best length of cable to match the PCB to the air cavity filter. More particularly, the T-junction matching approach cannot provide matching for all ports of a dual band duplexer structure.
Some embodiments advantageously provide hybrid structures, filters and duplexers. Accordingly, some embodiments provide combinations of air cavity resonators or filters with ceramic wave guide resonators or filters. Some combinations disclosed herein contribute no additional loss, the loss being only that of each filter in the combination. Further, some combinations disclosed herein are compact. Single band, dual band and multiband configurations are disclosed herein. Some embodiments are duplexers and multiplexers that provide high performance with less weight and complexity than known solutions.
According to one aspect, an electromagnetic structure is provided. The structure has an air cavity resonator having a resonator post, and at least a first side wall, the first side wall of the air cavity resonator having a first window parallel to a center axis of the resonator post. The structure also has a first ceramic waveguide, CWG, resonator having an opening in a side wall of the first CWG resonator, the opening being parallel to and at least partially aligned with the first window of the air cavity resonator to couple energy between the air cavity resonator and the CWG resonator. The structure also includes a first bridge having a length that extends from the resonator post through the first window of the air cavity resonator into an interior region of the CWG resonator.
According to this aspect, in some embodiments, the first bridge includes an electric conductor that makes contact with an edge of the first window of the air cavity resonator. In some embodiments, the first CWG resonator is configured to support a transverse electric (TE) mode with a magnetic field aligned with a magnetic field supported by the air cavity resonator. In some embodiments, the air cavity resonator has a second side wall having a second window and the structure further comprises: a second CWG resonator having a second opening in a side wall of the second CWG resonator, the second opening being parallel to and at least partially aligned with the second window of the air cavity resonator to couple energy between the air cavity resonator and the second CWG resonator. In some embodiments, the structure further includes a second bridge having a length that extends from the resonator post through the second window of the air cavity resonator into an interior region of the second CWG resonator. In some embodiments, the first window of the air cavity resonator is orthogonal to the second window of the air cavity resonator. In some embodiments, the first window of the air cavity resonator is at a first height above a bottom wall of the air cavity resonator and the second window of the air cavity resonator is at a second height above a bottom wall of the air cavity resonator, the second height being different from the first height. In some embodiments, the first CWG resonator and the second CWG resonator are rectangular with parallel broad walls and parallel narrow walls, the narrow walls being parallel to a center axis of the resonator post. In some embodiments, the first window of the air cavity resonator is at a first height above a bottom wall of the air cavity resonator, the first height being selected to obtain a specified minimum coupling bandwidth between the air cavity resonator and the first CWGF. In some embodiments, the second window of the air cavity resonator is at a second height above the bottom wall of the air cavity resonator, the second height being selected to reduce coupling of energy between the first and second CWG resonators to below a specified maximum allowable coupling. In some embodiments, the first window has a thickness forming a middle region between an interior region of the air cavity resonator and an interior region of the CWG resonator, the middle region having a material with a relative permittivity greater than one.
According to another aspect, a radio frequency (RF) duplexer is provided. The duplexer includes a common resonator being coupled to at least one chamber of an air cavity filter, the common resonator having a common resonator bottom wall, a plurality of common resonator side walls and a common resonator post, a first common resonator side wall of the plurality of common resonator side walls having a first window and a second common resonator side wall of the plurality of common resonator side walls having a second window. The duplexer also has a first ceramic waveguide filter, CWGF, having a first opening in a first CWG wall of the first CWGF, the first opening being parallel to and at least partially aligned with the first window of the common resonator to couple energy between the common resonator and the CWGF. The duplexer also has a second CWGF having a second opening in a second CWG wall of the second CWGF, the second opening being parallel to and at least partially aligned with the second window of the common resonator to couple energy between the air cavity resonator and the CWGF.
According to this aspect, in some embodiments, the first CWGF has a first CWG bottom wall positioned at a first height above the common resonator bottom wall and the second CWGF has a second CWG bottom wall at a second height above the common resonator bottom wall, the first and second heights being equal. In some embodiments, the first CWGF has a first CWG bottom wall positioned at a first height above the common resonator bottom wall and the second CWGF has a second CWG bottom at a second height above the common resonator bottom wall, the first and second heights being unequal. In some embodiments, the first common resonator side wall of the plurality of common resonator side walls to which the first CWG wall is adjoined is orthogonal to the second common resonator side wall of the plurality of common resonator side walls to which the second CWG wall is adjoined. In some embodiments, the first common resonator side wall of the plurality of common resonator side walls is the same side wall as the second common resonator side wall of the plurality of common resonator side walls. In some embodiments, the duplexer also includes a first bridge having a first length that extends from an interior region of the common resonator to an interior region of the first CWGF through the first window and first opening. In some embodiments, the duplexer also includes a second bridge having a second length that extends from the interior region of the common resonator to an interior region of the second metal cavity through the second window and second opening. In some embodiments, the common resonator is coupled to a first chamber of a first air cavity filter and is coupled to a second chamber of a second air cavity filter. In some embodiments, the second CWGF has a plurality of resonator sections on a first level and another resonator section at an end and on a second level above the first level. In some embodiments, the first and second CWGs are coupled to a receiver and the air cavity filter is coupled to a transmitter.
According to yet another aspect, a dual band duplexer is provided. The duplexer includes a common resonator coupled on a first side of the common resonator to a chamber of a first air cavity filter and separately coupled on the first side to a chamber of a second air cavity filter. The duplexer also includes a first air cavity resonator having a first side coupled to a second side of the common resonator, the second side of the common resonator being opposite the first side of the common resonator. The duplexer also includes a second air cavity resonator having a first side coupled to the second side of the common resonator. The duplexer further includes a first ceramic waveguide filter, CWGF, coupled at an end wall to a second side of the first air cavity resonator, the second side of the first air cavity resonator being opposite the first side of the first air cavity resonator; and a second CWGF coupled at an end wall to a second side of the second air cavity resonator, the second side of the second air cavity resonator being opposite the first side of the second air cavity resonator.
According to this aspect, in some embodiments, the duplexer further includes a first bridge having a first length extending from an interior of the first air cavity resonator to an interior of the first CWGF through a first coupling window. In some embodiments, the duplexer also includes a second bridge having a second length extending from an interior of the second air cavity resonator to an interior of the second CWGF through a second coupling window. In some embodiments, dimensions of the second CWGF equal the corresponding dimensions of the first CWGF.
According to another aspect, an electromagnetic filter is provided. The electromagnetic filter includes an air cavity filter having: a bottom wall, parallel side walls, a first end wall at a first end of the air cavity filter, the first end wall having a first input/output port, and a second end wall at a second end of the air cavity filter opposite the first end of the air cavity filter. The air cavity filter also has a first chamber at the first end of the air cavity filter, the first chamber being formed in part by the first end wall and the parallel side walls; and a second chamber at the second end of the air cavity filter, the second chamber having a resonator post, the second chamber being formed in part by the second end wall and the parallel side walls, a first side wall of the parallel side walls having a first window located in the second chamber. The electromagnetic filter also includes a ceramic waveguide filter, CWGF, having parallel first and second broad walls, the first broad wall being adjacent to the first side wall of the parallel side walls, the first broad wall having an opening at least partially aligned with the first window located in the second chamber, the second broad wall having a second input/output port.
According to this aspect, in some embodiments, the electromagnetic filter further includes a bridge that extends from an interior region of the second chamber through the first window and the opening to an interior region of the CWGF. In some embodiments, the opening in the first broad wall of the CWGF and the second input/output port in the second broad wall of the CWGF are near opposite ends of the CWGF. In some embodiments, an area of the first broad wall of the CWGF is smaller than an area of the first side wall of the parallel side walls of the air cavity filter and wherein the opening is further away from the first input/output port than to the second input/output port. In some embodiments, the CWGF is configured to support a transverse electric (TE) mode with an electric field aligned with a radial electric field supported by the air cavity resonator.
A more complete understanding of the present embodiments, and the attendant advantages and features thereof, will be more readily understood by reference to the following detailed description when considered in conjunction with the accompanying drawings wherein:
Before describing in detail exemplary embodiments, it is noted that the embodiments reside primarily in combinations of apparatus components and processing steps related to hybrid structures, filters and duplexers. Accordingly, components have been represented where appropriate by conventional symbols in the drawings, showing only those specific details that are pertinent to understanding the embodiments so as not to obscure the disclosure with details that will be readily apparent to those of ordinary skill in the art having the benefit of the description herein. Like numbers refer to like elements throughout the description.
As used herein, relational terms, such as “first” and “second,” “top” and “bottom,” and the like, may be used solely to distinguish one entity or element from another entity or element without necessarily requiring or implying any physical or logical relationship or order between such entities or elements. The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the concepts described herein. 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 herein, specify the presence of stated features, integers, steps, operations, elements, and/or components, but do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and/or groups thereof.
In embodiments described herein, the joining term, “in communication with” and the like, may be used to indicate electrical or data communication, which may be accomplished by physical contact, induction, electromagnetic radiation, radio signaling, infrared signaling or optical signaling, for example. One having ordinary skill in the art will appreciate that multiple components may interoperate and modifications and variations are possible of achieving the electrical and data communication.
In some embodiments described herein, the term “coupled,” “connected,” and the like, may be used herein to indicate a connection, although not necessarily directly, and may include wired and/or wireless connections.
The term “network node” used herein can be any kind of network node comprised in a radio network which may further comprise any of base station (BS), radio base station, base transceiver station (BTS), base station controller (BSC), radio network controller (RNC), g Node B (gNB), evolved Node B (eNB or eNodeB), Node B, multi-standard radio (MSR) radio node such as MSR BS, multi-cell/multicast coordination entity (MCE), integrated access and backhaul (IAB) node, relay node, donor node controlling relay, radio access point (AP), transmission points, transmission nodes, Remote Radio Unit (RRU) Remote Radio Head (RRH), a core network node (e.g., mobile management entity (MME), self-organizing network (SON) node, a coordinating node, positioning node, MDT node, etc.), an external node (e.g., 3rd party node, a node external to the current network), nodes in distributed antenna system (DAS), a spectrum access system (SAS) node, an element management system (EMS), etc. The network node may also comprise test equipment.
Note that although terminology from one particular wireless system, such as, for example, 3GPP LTE and/or New Radio (NR), may be used in this disclosure, this should not be seen as limiting the scope of the disclosure to only the aforementioned system. Other wireless systems, including without limitation Wide Band Code Division Multiple Access (WCDMA), Worldwide Interoperability for Microwave Access (WiMax), Ultra Mobile Broadband (UMB) and Global System for Mobile Communications (GSM), may also benefit from exploiting the ideas covered within this disclosure.
Note further, that functions described herein as being performed by a wireless device or a network node may be distributed over a plurality of wireless devices and/or network nodes. In other words, it is contemplated that the functions of the network node and wireless device described herein are not limited to performance by a single physical device and, in fact, can be distributed among several physical devices.
Unless otherwise defined, all terms (including technical and scientific terms) used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this disclosure belongs. It will be further understood that terms used herein should be interpreted as having a meaning that is consistent with their meaning in the context of this specification and the relevant art and will not be interpreted in an idealized or overly formal sense unless expressly so defined herein. Some embodiments provide hybrid structures, filters and duplexers. More particular, some embodiments provide efficient ways to combine air cavity filters and/or resonators with ceramic waveguide (CWG) filters and/or resonators. In some embodiments, the hybrid structures, filters and duplexers may be used in network nodes.
Referring now to the drawing figures, in which like elements are referred to by like reference numerals, there is shown in
The electric and magnetic field lines in the CWG resonator 10 shown in
One disadvantage of the embodiment of
In the embodiment of
In some embodiments, a metal bridge 46 may extend from the resonator post 14 of the air cavity resonator 12 through the window 44, through the opening in the wall of the CWG resonator 10 and into the CWG resonator 10 by a distance L. The metal bridge 46 may be rectangular in cross section and have a side that makes electrically conductive contact with a lower edge 48 of the window 44. The presence of the metal bridge 46 greatly improves the coupling of energy between the air cavity resonator 12 and the CWG resonator 10, and this is true regardless of the size of the opening in the wall of the CWG resonator 10, in some embodiments. The amount of coupling between the air cavity resonator 12 and the CWG resonator 10 increases as the height H of the CWG resonator bottom wall 50 above the air cavity resonator bottom wall 52 increases, up to a certain point that can be determined by experimentation or simulation.
Table 1 shows the coupling bandwidths obtained in simulations for the configurations of
As explained in reference to
In the configuration of
Each CWGF 56a and 56b may be configured to have different pass bands centered at different frequencies. In a frequency duplex system, power to be transmitted by the antenna port 62 at a first transmit frequency is input to a first port at an end wall 70a of a first one of the air cavity filters 58a. Power to be transmitted by the antenna port 62 at a second transmit frequency is input to a second port at an end wall 70b of the second one of the air cavity filters 58b. The first and second air cavity filters 58a and 58b are coupled by a window 71 in the adjacent walls of adjacent air cavity filter sections 72a and 72b. Power received by the antenna port 62 at a first receive frequency is coupled to the first CWGF 56a via the first window 64a and power received by the antenna port 62 at a second receive frequency is coupled to the second CWGF 56b via the second window 64b. In some embodiments, none of the transmit frequencies are the same as any of the receive frequencies.
In some embodiments, the two CWGFs 56a and 56b have a rectangular cross section and are configured such that a line perpendicular to the broad walls of the CWGFs 56a and 56b are parallel to an axis of the resonator post 14. Further, the two CWGFs 56a and 56b may be configured to support a TE mode as shown in
In some embodiments, the CWGFs 76a and 76b have rectangular cross sections and are configured to support a TE mode having the electric field in a direction perpendicular to the upper and lower broad walls 84a and 84b of respective CWGFs 76a and 76b. In such configurations, the CWGFs 76a and 76b support magnetic fields that couple with a magnetic field of a TEM mode supported by the common resonator 60. Note also that the two windows 82a and 82b are in orthogonal walls 86 and 88 of the first air cavity filter 78a.
In the embodiment of
According to one aspect, an electromagnetic structure is provided. The structure has an air cavity resonator 12 having a resonator post 14, and at least a first side wall, the first side wall of the air cavity resonator 12 having a first window 44 parallel to a center axis of the resonator post 14. The structure also has a first ceramic waveguide, CWG, resonator 10 having an opening in a side wall of the first CWG resonator 10, the opening being parallel to and at least partially aligned with the first window 44 of the air cavity resonator to couple energy between the air cavity resonator 12 and the CWG resonator 10. The structure also includes a first bridge 46 having a length that extends from the resonator post 14 through the first window 44 of the air cavity resonator 12 into an interior region of the CWG resonator 10.
According to this aspect, in some embodiments, the first bridge 46 includes an electric conductor that makes contact with an edge of the first window 44 of the air cavity resonator 12. In some embodiments, the first CWG resonator 10 is configured to support a transverse electric (TE) mode with a magnetic field aligned with a magnetic field supported by the air cavity resonator 12. In some embodiments, the air cavity resonator 12 has a second side wall having a second window 45b and the structure further comprises: a second CWG resonator 10b having a second opening in a side wall of the second CWG resonator 10b, the second opening being parallel to and at least partially aligned with the second window 45b of the air cavity resonator 12 to couple energy between the air cavity resonator 12 and the second CWG resonator 10b. In some embodiments, the structure further includes a second bridge having a length that extends from the resonator post 14 through the second window 45b of the air cavity resonator 12 into an interior region of the second CWG resonator 10b. In some embodiments, the first window 45a of the air cavity resonator 12 is orthogonal to the second window 45b of the air cavity resonator 12. In some embodiments, the first window 45a of the air cavity resonator 12 is at a first height above a bottom wall 52 of the air cavity resonator 12 and the second window 45b of the air cavity resonator 12 is at a second height above the bottom wall 52 of the air cavity resonator 12, the second height being different from the first height. In some embodiments, the first CWG resonator 10a and the second CWG resonator 10b are rectangular with parallel broad walls and parallel narrow walls, the narrow walls being parallel to a center axis of the resonator post 14. In some embodiments, the first window 45a of the air cavity resonator 12 is at a first height above the bottom wall 52 of the air cavity resonator, the first height being selected to obtain a specified minimum coupling bandwidth between the air cavity resonator 12 and the first CWGF 56a. In some embodiments, the second window 45b of the air cavity resonator 12 is at a second height above the bottom wall 52 of the air cavity resonator 12, the second height being selected to reduce coupling of energy between the first and second CWG resonators 10a and 10b to below a specified maximum allowable coupling. In some embodiments, the first window 45a has a thickness forming a middle region between an interior region of the air cavity resonator 12 and an interior region of the CWG resonator 10a, the middle region having a material with a relative permittivity greater than one.
According to another aspect, a radio frequency (RF) duplexer is provided. The duplexer 54, 74, 94, 106, 120 includes a common resonator 60 being coupled to at least one chamber 71a of an air cavity filter 58a, the common resonator 60 having a common resonator bottom wall, a plurality of common resonator side walls and a common resonator post 14, a first common resonator side wall of the plurality of common resonator side walls having a first window 64a and a second common resonator side wall of the plurality of common resonator side walls having a second window 64b. The duplexer also has a first ceramic waveguide filter 56a, CWGF, having a first opening in a first CWG wall of the first CWGF 56a, the first opening being parallel to and at least partially aligned with the first window 64a of the common resonator 60 to couple energy between the common resonator 60 and the CWGF 56a. The duplexer also has a second CWGF 56b having a second opening in a second CWG wall of the second CWGF 56b, the second opening being parallel to and at least partially aligned with the second window 64b of the common resonator 60 to couple energy between the common resonator 60 and the CWGF 56b.
According to this aspect, in some embodiments, the first CWGF 56a has a first CWG bottom wall positioned at a first height above the common resonator bottom wall and the second CWGF has a second CWG bottom wall at a second height above the common resonator bottom wall, the first and second heights being equal. In some embodiments, the first CWGF 56a has a first CWG bottom wall positioned at a first height above the common resonator bottom wall and the second CWGF 56b has a second CWG bottom at a second height above the common resonator bottom wall, the first and second heights being unequal. In some embodiments, the first common resonator side wall of the plurality of common resonator side walls is orthogonal to the second common resonator side wall of the plurality of common resonator side walls. In some embodiments, the first common resonator side wall of the plurality of common resonator side walls is the same side wall as the second common resonator side wall of the plurality of common resonator side walls. In some embodiments, the duplexer also includes a first bridge 46 having a first length that extends from an interior region of the common resonator 60 to an interior region of the first CWGF 56a through the first window 64a and first opening. In some embodiments, the duplexer also includes a second bridge 46 having a second length that extends from the interior region of the common resonator 60 to an interior region of the second CWG 56b through the second window 64b and second opening. In some embodiments, the common resonator 60 is coupled to a first chamber 72a of a first air cavity filter 58a and is coupled to a second chamber 72b of a second air cavity filter 58b. In some embodiments, the second CWGF 76a has a plurality of resonator sections on a first level and another resonator section 80a at an end and on a second level above the first level. In some embodiments, the first and second CWGs 76a and 76b are coupled to a receiver and the air cavity filters 58a and 58b is coupled to a transmitter.
According to yet another aspect, a dual band duplexer is provided. The duplexer includes a common resonator 60 coupled on a first side of the common resonator 60 to a chamber of a first air cavity filter 110a and separately coupled on the first side to a chamber of a second air cavity filter 110b. The duplexer also includes a first air cavity resonator 114a having a first side coupled to a second side of the common resonator 60, the second side of the common resonator 60 being opposite the first side of the common resonator 60. The duplexer also includes a second air cavity resonator 114b having a first side coupled to the second side of the common resonator 60. The duplexer further includes a first ceramic waveguide filter, CWGF 108a, coupled at an end wall to a second side of the first air cavity resonator 114a, the second side of the first air cavity resonator 114a being opposite the first side of the first air cavity resonator 114a; and a second CWGF 108b coupled at an end wall to a second side of the second air cavity resonator 114b, the second side of the second air cavity resonator 114b being opposite the first side of the second air cavity resonator 114b.
According to this aspect, in some embodiments, the duplexer further includes a first bridge 46 having a first length extending from an interior of the first air cavity resonator 114a to an interior of the first CWGF 108a through a first coupling window 116a. In some embodiments, the duplexer also includes a second bridge 46 having a second length extending from an interior of the second air cavity resonator 114b to an interior of the second CWGF 108b through a second coupling window 116b. In some embodiments, dimensions of the second CWGF 108b equal the corresponding dimensions of the first CWGF 108a.
According to another aspect, an electromagnetic filter is provided. The electromagnetic filter includes an air cavity filter 24 having: a bottom wall, parallel side walls, a first end wall 34 at a first end of the air cavity filter 24, the first end wall 34 having a first input/output port 36, and a second end wall at a second end of the air cavity filter 24a opposite the first end of the air cavity filter 24. The air cavity filter 24 also has a first chamber 12d at the first end of the air cavity filter 24, the first chamber 12d being formed in part by the first end wall 34 and the parallel side walls; and a second chamber 12a at the second end of the air cavity filter 24, the second chamber 12a having a resonator post 14a, the second chamber 12a being formed in part by the second end wall and the parallel side walls, a first side wall of the parallel side walls having a first window 28 located in the second chamber 12a. The electromagnetic filter also includes a ceramic waveguide filter, CWGF 26, having parallel first and second broad walls, the first broad wall being adjacent to the first side wall of the parallel side walls, the first broad wall having an opening at least partially aligned with the first window 28 located in the second chamber 12a, the second broad wall having a second input/output port 32.
According to this aspect, in some embodiments, the electromagnetic filter further includes a bridge 46 that extends from an interior region of the second chamber 12a through the first window 28 and the opening to an interior region of the CWGF 26. In some embodiments, the opening in the first broad wall of the CWGF 26 and the second input/output port 32 in the second broad wall of the CWGF 26 are in proximity to opposite ends of the CWGF 26. In some embodiments, an area of the first broad wall of the CWGF 26 is smaller than an area of the first side wall of the parallel side walls of the air cavity filter 24 and wherein the opening is further away from the first input/output port 36 than to the second input/output port 32. In some embodiments, the CWGF 26 is configured to support a transverse electric (TE) mode with an electric field aligned with a radial electric field supported by the second chamber 12a.
Many different embodiments have been disclosed herein, in connection with the above description and the drawings. It will be understood that it would be unduly repetitious and obfuscating to literally describe and illustrate every combination and subcombination of these embodiments. Accordingly, all embodiments can be combined in any way and/or combination, and the present specification, including the drawings, shall be construed to constitute a complete written description of all combinations and subcombinations of the embodiments described herein, and of the manner and process of making and using them, and shall support claims to any such combination or subcombination.
It will be appreciated by persons skilled in the art that the embodiments described herein are not limited to what has been particularly shown and described herein above. In addition, unless mention was made above to the contrary, it should be noted that all of the accompanying drawings are not to scale. A variety of modifications and variations are possible in light of the above teachings without departing from the scope of the following claims.
Filing Document | Filing Date | Country | Kind |
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PCT/IB2022/052179 | 3/10/2022 | WO |
Number | Date | Country | |
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63168626 | Mar 2021 | US |