Phase shifter module comprising a device for physically separating a phase shifter from a matching device while electrically connecting the phase shifter and the matching device

Abstract

A phase shifter module arrangement comprises a phase shifter with a plurality of emitter connections and a central point connection. A matching network is provided. The matching network comprises a signal connection and a phase shifter connection. A separating device is provided which is electrically conductive and is arranged between the phase shifter and the matching network. The separating device has a first side on which the phase shifter is arranged and a second side on which the matching network is arranged. A connection opening connects the first side to the second side. The phase shifter connection of the matching network is connected electrically via the connection opening of the separating device to the central point connection of the phase shifter.

Claims

1. A phase shifter module arrangement for use in a mobile communications antenna having the following features: a phase shifter is provided; the phase shifter comprises a plurality of emitter connections for connection to different emitter elements of a mobile communications antenna; the phase shifter comprises a central point connection, wherein the phase shifter is configured to output a high-frequency signal which is present at the central point connection thereof to emitter connections thereof; a matching network is provided; the matching network comprises a signal connection and a phase shifter connection; a separating device is provided which is electrically conductive and is arranged between the phase shifter and the matching network wherein the separating device consists of or comprises metal; or the separating device is formed from a dielectric material which is provided with an electrically conductive layer; or the separating device consists of or comprises plastic, wherein electrically conductive particles are integrated in the plastic; the separating device has a first side on which the phase shifter is arranged or which is facing the phase shifter and a second side on which the matching network is arranged or which faces the matching network; the separating device comprises a connection opening which extends from the first side to the second side; the phase shifter connection of the matching network is connected electrically via the connection opening of the separating device to the central point connection of the phase shifter; a phase shifter cover arrangement is provided which is arranged on the first side of the separating device, wherein a phase shifter receiving space is formed between the phase shifter cover arrangement and the separating device, in which the phase shifter is arranged; a matching network cover arrangement is provided which is arranged on the second side of the separating device, wherein a matching network receiving space is formed between the matching network cover arrangement and the separating device in which the matching network is arranged.

2. The phase shifter module arrangement according to claim 1, characterized by the following feature: the first side of the separating device is arranged opposite the second side of the separating device.

3. The phase shifter module arrangement according to claim 1, characterized by the following features: the phase shifter cover arrangement is screwed to the separating device and the matching network cover arrangement is screwed to the separating device; or the phase shifter cover arrangement is screwed to the matching network cover arrangement, wherein the separating device is clamped between the phase shifter cover arrangement and the matching network cover arrangement.

4. The phase shifter module arrangement according to claim 1, characterized by the following feature: the phase shifter is a difference phase shifter.

5. The phase shifter module arrangement according to claim 1, characterized by the following features: the phase shifter comprises a plurality of arcuate strip lines; the plurality of arcuate strip lines have connections ends which are electrically connected to the respective emitter connections; the phase shifter comprises a pickup which is rotatable about an axis of rotation; the pickup extends from the axis of rotation towards all of the arcuate strip conductors and contacts the arcuate strip conductors galvanically or capacitively; the pickup is connected galvanically or capacitively to the central point connection in a region of the axis of rotation.

6. The phase shifter module arrangement according to claim 5, characterized by the following features: the phase shifter comprises an axial element; the axial element is connected to the pickup; the phase shifter cover arrangement and, the matching network cover arrangement each comprise an opening which is penetrated by the axis of rotation of the pickup, wherein the axial element extends through these openings and the connection opening.

7. The phase shifter module arrangement according to claim 5, characterized by the following features: the arcuate strip lines of the phase shifter extend around a centre point; the axis of rotation of the pickup extends through the centre point of the arcuate strip lines.

8. The phase shifter module arrangement according to claim 1, characterized by the following feature: a first circumferential side wall is arranged between the first side of the separating device and the phase shifter cover arrangement; the emitter connections of the phase shifter are arranged on the first circumferential side wall.

9. The phase shifter module arrangement according to claim 1, characterized by the following feature: the matching network is a strip conductor part, wherein a first strip line extends from the signal connection of the matching network to the phase shifter connection of the matching network.

10. The phase shifter module arrangement according to claim 9, characterized by the following feature: the matching network is a stamped and/or laser-cut and/or bent part and/or a structured printed circuit board and/or a metallized plastic.

11. The phase shifter module arrangement according to claim 9, characterized by the following feature: the matching network consists of or comprises metal, metal sections and/or metal strips.

12. The phase shifter module arrangement according to claim 9, characterized by the following feature: the matching network is formed in one part.

13. The phase shifter module arrangement according to claim 9, characterized by the following feature: the phase shifter connection of the matching network is soldered to the central point connection of the phase shifter; or the phase shifter connection of the matching network is formed in one piece with the central point connection of the phase shifter.

14. The phase shifter module arrangement according to claim 9, characterized by the following feature: the first strip line of the matching network comprises at least one branch line with an open-circuited or short-circuited end, wherein the at least one branch line is dimensioned with regard to the length thereof in such a manner that pre-determined frequencies or frequency bands can be filtered between the signal connection of the matching network and the phase shifter connection of the matching network.

15. The phase shifter module arrangement according to claim 9, characterized by the following features: the matching network comprises a first central system connection for connection to a further emitter element of a mobile communications antenna; the matching network comprises a second strip line; the second strip line connects the first central system connection to a connection point from the first strip line, wherein the connection point lies between the signal connection and the phase shifter connection.

16. The phase shifter module arrangement according to claim 15, characterized by the following feature: a width of at least one part of the first strip line between the connection point and the phase shifter connection is different from a width of at least a part of the second strip line with the result that a high-frequency signal at the phase shifter connection has a different power level than at the first central system connection.

17. The phase shifter module arrangement according to claim 15, characterized by the following feature: the second strip line comprises a branch line with an open-circuited or short-circuited end.

18. The phase shifter module arrangement according to claim 17, characterized by the following feature: the end of the branch line which originates at the second strip line is soldered to the matching network cover arrangement.

19. The phase shifter module arrangement according to claim 18, characterized by the following features: the matching network cover arrangement comprises a hole pattern wherein a conducting connection is guided through an opening of the hole pattern and wherein the conducting connection is galvanically connected to the matching network cover arrangement and to the end of the branch line which originates at the second strip line; the openings of the hole pattern are less than ?/10 of the high-frequency signal at the signal connection.

20. The phase shifter module arrangement according to claim 19, characterized by the following feature: the conducting connection is formed from a part of the matching network.

21. The phase shifter module arrangement according to claim 15, characterized by the following features: the matching network comprises a second central system connection for connection to a further emitter element of a mobile communications antenna; the matching network comprises a third strip line; the third strip line connects the second central system connection to: a) a connection point on the first strip line, wherein the connection point lies between the signal connection and the phase shifter connection; b) a further connection point on the second strip line, wherein the further connection point lies between the connection point on the first strip line and the first central system connection.

22. The phase shifter module arrangement according to claim 1, characterized by the following feature: located between the matching network cover arrangement and the matching network is a first insulating arrangement which comprises of a dielectric material, wherein the first insulating arrangement comprises a grid structure; and/or located between the second side of the separating device and the matching network is a second insulating arrangement which comprises of a dielectric material, wherein the second insulating arrangement comprises a grid structure.

23. The phase shifter module arrangement according to claim 1, characterized by the following features: a second circumferential side wall is arranged between the second side of the separating device and the matching network cover arrangement; the signal connection of the matching network is arranged on the second circumferential side wall.

24. The phase shifter module arrangement according to claim 1, characterized by the following feature: a first tuning device is provided; and the first tuning device comprises a dielectric tuning element.

25. The phase shifter module arrangement according to claim 24, characterized by the following feature: the first tuning device is accessible from outside the phase shifter cover arrangement and from outside the matching network cover arrangement.

26. The phase shifter module arrangement according to claim 1, characterized by the following feature: a second tuning device is provided; the second tuning device comprises a dielectric tuning element; the second tuning device comprises an adjusting and latching device in order to displace the dielectric element by an adjustable length over a connection line between the signal connection of the matching network and the phase shifter connection of the matching network on the second side of the separating device, with the result that the phase shifter module arrangement can be tuned.

27. The phase shifter module arrangement according to claim 26, characterized by the following feature: the second tuning device is accessible from outside the phase shifter cover arrangement and from outside the matching network cover arrangement.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) Various exemplary embodiments of the invention will be described as an example hereinafter with reference to the drawings. The same items have the same reference numbers throughout the detail description of the drawings. The corresponding figures of the drawings show in detail:

(2) FIG. 1: shows a view of the phase shifter module arrangement with the phase shifter cover arrangement removed, which describes the structure of the phase shifter in greater detail;

(3) FIG. 2: shows a view of the phase shifter module arrangement with the matching network cover arrangement removed, which describes the structure of the matching network in greater detail;

(4) FIG. 3: shows a cross-section through the phase shifter module arrangement;

(5) FIGS. 4A, 4B, 4C: show various exemplary embodiments of the matching network;

(6) FIG. 5A: shows a view of an exemplary embodiment of an inner side of the matching network cover arrangement; and

(7) FIG. 5B: shows a view of an exemplary embodiment of an outer side of the matching network cover arrangement.

DETAILED DESCRIPTION

(8) The structure of the phase shifter module arrangement 1 according to the invention is described in detail. This phase shifter module arrangement 1 comprises a phase shifter 2 and a matching network 3 which are fastened to a common separating device 4 in such a manner that the phase shifter module arrangement 1 is obtained therefrom. This can be mounted separately and tested in advance, i.e. before mounting in a mobile communications antenna. Errors in the final mounting of the mobile communications antenna are thereby substantially reduced.

(9) FIG. 1 shows a view of the phase shifter module arrangement 1 with a phase shifter cover arrangement 5 removed (see FIG. 3) in order to explain the structure of the phase shifter 2 in greater detail.

(10) The phase shifter 2 comprises a plurality of emitter connections 7 which are suitable for connection to various emitter elements of a mobile communications antenna. The phase shifter 2 additionally comprises a central point connection 8 and is configured to output a high-frequency signal (e.g. mobile communications signal) which is present at the central point connection 8 thereof to emitter connections 7 thereof in a phase-shifted manner. Preferably this high-frequency signal is applied to the respective emitter connections 7 in each case with a different phase.

(11) The phase shifter 2 in FIG. 1 is a difference phase shifter. Other phase shifters can also be used. The structure of the phase shifter module arrangement will be described hereinafter for a difference phase shifter.

(12) The phase shifter 2 comprises a plurality of arcuate strip lines 9. The arcuate strip lines 9 have connection ends 9a, 9b which are electrically connected to the respective emitter connections 7. The phase shifter 2 additionally comprises a pickup 10 which is rotatable about an axis of rotation 11. The Pickup 10 extends in this case from the axis of rotation 11 via all the arcuate strip lines 9 and contacts these strip lines galvanically or capacitively. The pickup 10 is connected galvanically or capacitively to the central point connection 8 in the region of an axis of rotation 11. Preferably capacitive connections are provided.

(13) The arcuate strip lines 9 of the phase shifter 2 preferably extend about the same central point. The axis of rotation 11 of the pickup 10 preferably also extends through this central point of the arcuate strip lines 9. The arcuate strip lines are arranged concentrically about the axis of rotation 11.

(14) The phase shifter 2 further comprises an axial element 12. This axial element 12 is shown in FIG. 3. FIG. 3 shows a cross-section through the phase shifter module arrangement 1 according to the invention. The axial element 12 is connected; in a rotationally coupled manner to the pickup 10. The phase shifter cover arrangement 5 and a matching network cover arrangement 6 as well as the separating device 4 each comprise an opening which is penetrated by the axis of rotation 11 of the pickup 10, wherein the axial element 12 also extends through these openings. The axial element 12 can be mounted in the corresponding cover arrangements 5, 6 and/or the separating device 4. The axial element 12 can be rotated by means of a drive arrangement which, for example, can be formed by a push rod, not shown, with a gear wheel segment. A shaft with a cardan joint can also be used instead of the push rod. Other drive solutions are also feasible.

(15) Not shown is a possible use of dielectric spacers by means of which the arcuate strip lines 9 of the phase shifter 2 are arranged at a distance from a first side 4a of the separating device 4. Also not shown is a possible use of dielectric spacers by means of which the arcuate strip lines 9 of the phase shifter 2 are arranged at a distance from the phase shifter cover arrangement 5.

(16) It is also shown in FIG. 3 that the central point connection 8 of the phase shifter 2 is coupled capacitively to the pickup 10 (see air gap).

(17) FIG. 2 shows a view of the phase shifter module arrangement 1 with the matching network cover arrangement removed, with the result that the structure of the matching network 3 can be described in greater detail.

(18) As will be explained further hereinafter, the matching network 3 comprises various functions. On the one hand, the power can be distributed between various connections. In addition, a blocking effect against specific frequencies or mobile communications bands can be provided. It is also possible that the transmission phase between a central system and the phase shifter 2 from FIG. 1 is matched by the matching network. It is also possible to match the connections to a specific impedance value. A DC ground can also be achieved.

(19) With a view to FIG. 2, it is shown that the matching network 3 comprises a signal connection 15 and a phase shifter connection 16. With a view to FIG. 3, the separating device 4 is shown which is electrically conductive and is arranged between the phase shifter 2 and the matching network 3. The separating device 4 in this case has a first side 4a on which the phase shifter 2 is arranged or which is facing the phase shifter 2. The separating device 4 additionally has a second side 4b on which the matching network 3 is arranged or which faces the matching network 3. The separating device 4 additionally comprises a connection opening 17 which extends from the first side 4a to the second side 4b. The phase shifter connection 16 of the matching network 3 is in this case electrically connected to the central point connection 8 of the phase shifter 2 via the connection opening 17 of the separating device 4. This connection preferably comprises a galvanic connection. Preferably the phase shifter connection 16 is soldered to the central point connection 8.

(20) FIG. 3 also shows the phase shifter cover arrangement 5 which is arranged on the first side 4a of the separating device 4. In this case, the phase shifter receiving space 5a in which the phase shifter 2 is arranged, is formed between the phase shifter cover arrangement 5 and the separating device 4.

(21) Likewise, the matching network cover arrangement 6 which is arranged on the second side 4b of the separating device 4 is also shown. In this case, a matching network receiving space 6a in which the matching network 3 is arranged is formed between the matching network cover arrangement 6 and the separating device 4.

(22) The first side 4a and the second side 4b of the separating device 4 are arranged opposite one another. Both sides 4a, 4b run parallel to one another.

(23) The matching network receiving space 6a is preferably free from a phase shifter 2. On the other hand, the phase shifter receiving space 5a is preferably free from a matching network 3.

(24) The separating device 4 consists of or comprises a metal. This results in a shielding effect between the phase shifter receiving space 5a and the matching network receiving space 6a. The separating device 4 could also be formed from a dielectric material which is provided with an electrically conductive layer. In principle, it would also be possible that the separating device 4 consists of a plastic or is comprised thereof such, wherein electrically conductive particles are integrated in the plastic.

(25) The phase shifter cover arrangement 5 is preferably screwed to the separating device 4. A capacitive coupling or a clamping would also be possible. The same can also apply to the matching network cover arrangement 6. However, it would also be possible that the phase shifter cover arrangement 5 is screwed directly to the matching network cover arrangement 6, wherein the separating device 4 has a corresponding screw opening. By tightening the screw arrangement, the phase shifter cover arrangement 5 and the matching network cover arrangement 6 are moved towards one another and the separating device 4 is clamped between two cover arrangements 5a, 6a.

(26) In principle, a first circumferential side wall 20a can be arranged between the first side 4a of the separating device 4 and the phase shifter cover arrangement 5. The emitter connections 7 of the phase shifter 2 from FIG. 1 are then preferably arranged on this first circumferential side wall 20a.

(27) A second circumferential side wall 20b can also be arranged between the second side 4b of the separating device 4 and the matching network cover arrangement 6. The signal connection 15 of the matching network 3 can then be arranged on this second circumferential side wall 20b.

(28) A possible structure of the matching network 3 will be described in detail hereinafter with a view to FIG. 2. The matching network 2 is preferably formed in a stripline technique. This comprises a first strip line 30 which extends from the signal connection 15 to the phase shifter connection 16. This first strip line 30 consists of or comprises metal and is preferably formed in one part. This applies further preferably to the entire matching network 3. In principle, the matching network 3 can also consist of various metal sections or metal strips which are joined together, in particular soldered together.

(29) The first strip line 30 of the matching network 3 preferably comprises at least one branch line 31 (two branch lines of different thickness are shown in FIG. 2). This at least one branch line 31 comprises an open end in this exemplary embodiment. However, the end could also be short-circuited, to which reference will be made subsequently. The at least one branch line 31 is dimensioned with regard to the length thereof in such a manner that pre-determined frequencies or frequency bands are damped, i.e. filtered between the signal connection 15 and the phase shifter connection 16. The branch lines 31 are also used for impedance transformation.

(30) This branch line 31 can however also be short-circuited at the open end thereof. Such a short-circuiting preferably takes place towards the phase shifter cover arrangement 6.

(31) The matching network 3 is preferably configured as a stamped and/or laser-cut and/or bent part. The matching network 3 can also be constructed from a printed circuit board with corresponding structures (structured printed circuit board) or metallized plastic or comprise these.

(32) Further exemplary embodiments of the matching network 3 are described with a view to FIGS. 4A, 4B and 4C.

(33) In FIGS. 4A and 4B, the matching network 3 also comprises a first central system connection 35. This is used for connection to a further emitter element of a mobile communications antenna. This further emitter element preferably comprises an emitter element in the centre of the mobile communications antenna. In this case, the matching network 3 comprises a second strip line 32. The second strip line 32 connects the first central system connection 35 to a connection point 33 on the first strip line 30. This connection point 33 lies between the signal connection 15 and the phase shifter connection 16. This connection comprises an electrical connection. Both strip lines 30, 32 are preferably constructed in one part. These strip lines therefore further preferably consist of a common stamped and/or laser-cut part.

(34) It is also shown that the width of at least one part of the first strip line 30 between the connection point 33 and the phase shifter connection 16 is different from a width of at least one part of the second strip line 32. As a result, a power distribution can be achieved. The level of the high-frequency signal which is output at the central system connection 35 and at the phase shifter connect 16 can thus be different. Instead of an increased width, it is also possible to talk of a thickening, wherein this preferably only takes place two-dimensionally, i.e. in one plane.

(35) The matching network 3 preferably extends only in one plane.

(36) The strip lines 30, 32 extend parallel to the separating device 4 and furthermore parallel to the arcuate strip lines 9 of the phase shifter 2 as shown in FIG. 1.

(37) It is shown in FIG. 4B that the second strip line comprises another branch line 34, the end of which is short-circuited (black point). The end could also be open-circuited. Due to a short-circuit, a DC ground is provided with the result that induced currents which, for example, are caused by neighbouring lightning strikes are diverted. The further branch line 34 also serves to achieve a correction of the transmission phase. This means that with a fixed setting of the phase shifter 2 between the emitter connections 7 as shown in FIG. 1 and the first central system connection 35 over the frequency range in which the phase shifter module arrangement 1 is operated, the phase shift is constant.

(38) The structure of a short-circuit connection is shown, for example, in FIG. 3. Thus, a conducting connection 40 which can, for example, comprise a solder pin is used to connect a part of the matching network 3 (in this case, the further branch line 34) to a reference (in this case, the housing). The end of the further branch line 34 which originates at the second strip line 32 is in this case soldered to the matching network cover arrangement 6. The conducting connection 40 can also be connected in one piece to the matching network 3. A part of the matching network 3 can be bent in the direction of the matching network cover arrangement 6 and can be galvanically connected to this, e.g. soldered.

(39) With a view to FIG. 5B it is shown that the matching network cover arrangement 6 comprises a hole pattern 50. This hole pattern 50 consists of a plurality of openings. These openings can in this case be less than ?/10 of the high-frequency signal which is supplied or received at the signal connection in FIG. 4C. The conducting connection (e.g. solder pin) 40 from FIG. 3 is in this case guided through a suitable opening of the hole pattern 50 and is soldered both to the matching network cover arrangement 6 and also in the corresponding part of the matching network 3 in FIG. 3, i.e. to the branch line 34 of the second strip line 32 from FIG. 4C.

(40) The hole pattern 50 is preferably regular and therefore symmetrically constructed. This means that the spacing of the individual openings with respect to one another is (approximately) the same.

(41) It is further shown in FIG. 4C that the matching network 3 also comprises a second central system connection 36. This is also used for connection to a further emitter element of the mobile communications antenna. There is preferably no phase offset between the first and the second central system connection 35, 36. However, this phase offset could also be set, e.g. by cables of different length which are connected to the central system connections 35, 36. The further emitter elements are preferably those in the centre of the mobile communications antenna. In FIG. 4C the matching network 3 also comprises a third strip line 37. The third strip line 37 connects (electrically) the second central system connection 36 to a connection point on the first strip line 30, wherein the connection point lies between the signal connection 15 and the phase shifter connection 16. This can be the same connection point 33 at which the second strip line 32 is connected to the first strip line 30. However, it can also comprise a further connection point which is spaced apart from the first connection point 33. However, it is shown in FIG. 4C that the third strip line 37 connects the second central system connection 36 to a further connection point 38 which lies on the second strip line 32, wherein the further connection point 38 lies between the connection point 33 on the first strip line and the first central system connection 35.

(42) In order to be able to suitably match the matching network 3, a first tuning device 60 and a second tuning device 61 are shown with a view to FIG. 3. The first tuning device 60 in this case comprises a dielectric tuning element 60a. The first tuning device 60 also comprises an adjusting and latching device (not shown) in order to be able to displace the dielectric tuning element 60a by a pre-determined (adjustable) length over a connecting line between the phase shifter connection 16 of the matching network 3 and the central point connection 8 of the phase shifter 2 on the first side 4a of the separating device 4. The phase shifter module arrangement 1 can thereby be tuned. The adjusting and latching device can, for example, be formed by means of a knurl. In this case, the first tuning device 60 is accessible and adjustable from outside, i.e. when the phase shifter cover arrangement 5 is closed.

(43) The same applies to the second tuning device 61. This also comprises a dielectric tuning element 61a and an adjusting and latching device (not shown). By means of the adjusting and latching device, the dielectric tuning element 61a can be displaced by an adjustable length over a connecting line between the signal connection 15 of the matching network 3 and the phase shifter connection 16 of the matching network 3 on the second side 4b of the separating device 4. Preferably the dielectric tuning element 61a of the second tuning device 61 is arranged between the connection point 33 on the first strip line 30 and the phase shifter connection 16. The second tuning device 61 is preferably also adjustable from outside the phase shifter module arrangement 1. In particular, the second tuning device 61 is accessible when the phase shifter cover arrangement 6 is closed.

(44) By using these tuning devices 60, 61, a tuning can be achieved on the phase shifter side and matching network side. It is thereby ensured that the input resistances (impedances) at the respective connections (e.g. signal connection 15) preferably correspond to 50 Ohm.

(45) By means of the tuning devices 60, 61, the impedance curve in the Smith chart for the phase shifter side and the matching network side can be set in all directions.

(46) FIG. 5A also shows a view of an exemplary embodiment of an inner side of the matching network cover arrangement 6. A first insulating arrangement 70 which consists of a dielectric material from FIG. 5B is arranged between the matching network cover arrangement 6 and the matching network 3. This first insulating arrangement 70 has a grid structure. The grid structure comprises cavities 71. Dielectric elements can be clipped in or pressed in or latched into these cavities of the grid structure. By this means the matching network 3 can also be tuned. The grid structure is preferably configured to be regular and in particular has a diamond shape or a square shape. In principle, the shape is arbitrary. The size of the cavities 71 can be suitably selected in precisely the same way. Depending on where the matching network 3 is arranged, the corresponding cavity 71 can be filled with a corresponding dielectric element if required. The matching network 3 then rests on this first insulating arrangement 70.

(47) Additionally or alternatively a second insulating arrangement (not shown) can be arranged between the second side 4b of the separating device 4 and the matching network 3. This can also consist of a dielectric material or comprise such, wherein the second insulating arrangement can also have a grid structure. A dielectric element can also be clipped in, pressed in and/or latched into this grid structure of the second insulating arrangement to tune the matching network 3.

(48) A mobile communications antenna could also be claimed comprising at least one or at least two of the described phase shifter module arrangements 1. The at least one phase shifter module arrangement 1 would preferably be arranged within the mobile communications antenna housing but could also be arranged outside of the mobile communications antenna housing. The mobile communications antenna also comprises a plurality of emitter elements (e.g. each of them could be used in two polarizations) connected to the phase shifter 2 of the at least one phase shifter module arrangement 1.

(49) Some of the embodiments contemplated herein are described more fully with reference to the accompanying drawings. Other embodiments, however, are contained within the scope of the subject matter disclosed herein. The disclosed subject matter should not be construed as limited to only the embodiments set forth herein; rather, these embodiments are provided by way of example to convey the scope of the subject matter to those skilled in the art.

(50) The present invention may, of course, be carried out in other ways than those specifically set forth herein without departing from essential characteristics of the invention. The present embodiments are to be considered in all respects as illustrative and not restrictive, and all changes coming within the meaning and equivalency range of the appended claims are intended to be embraced therein.