N-path radio frequency power divider-combiner and device comprising same

Abstract

The invention relates to an N-path radio frequency power divider-combiner and a device comprising the same. Disclosed is an N-way radio frequency (RF) power divider-combiner comprising: an inner conductor (6) comprising: a plurality of (N) stepped cross-section conductor branches (1) extending radially and circumferentially uniformly spaced from a central end (3) in a reference plane (R); and a conductor stem (2) of stepped cross-section extending from the central end (3) perpendicular to the reference plane (R). This avoids power imbalance and excessive attenuation.

Description

TECHNICAL FIELD

[0001] The present invention relates generally to the field of radio frequency (RF) engineering, and in particular to an N-way RF power divider-combiner and a device comprising the same. BACKGROUND

[0002] Wilkinson RF couplers use quarter wavelength transformations to achieve isolation between output ports and matching of all ports.

[0003] Due to reciprocity, such RF couplers are composed of passive components only, and can thus be used as power dividers and combiners.

[0004] Typically, isolation resistors between output ports are used to suppress power imbalance due to non-idealities. However, significant power imbalance can also occur in planar Wilkinson designs with more than two ports, e.g. due to electrically asymmetric layout, which can result in excessive attenuation.

[0005] Printed Wilkinson designs typically cannot transmit high RF power. SUMMARY

[0006] It is an object to overcome the above and other disadvantages.

[0007] The above and other objects are achieved by the technical solutions of the present invention. Further implementation forms are apparent from the present invention.

[0008] According to a first aspect, there is provided an N-way radio frequency (RF) power divider-combiner comprising: an inner conductor comprising a plurality of conductor branches having a varying (i.e. continuously varying or stepped) cross-section and extending from a center end uniformly spaced radially and circumferentially in a reference plane; and a conductor stem having a varying (i.e. continuously varying or stepped) cross-section and extending from the center end perpendicular to the reference plane.

[0009] Hereby, the varying cross-sections are such that the profile tapers from one end to the other.

[0010] As used herein, N-way can refer to N (partial power) branches and a single (total power) stem.

[0011] As used herein, center end can refer to a common end or star node.

[0012] As used herein, stem can refer to a conductor having a solid cross-section and no voids.

[0013] As used herein, a stepped cross-section can guide a stepped variation of the cross-section (and thus impedance) of the conductor along the conductor.

[0014] The conductor stem and the plurality of conductor branches can be fastened at the center end. Any kind of fastening can be used, such as welding, screw fastening, soldering, or just made from a single piece, such as using 3d printing or milling.

[0015] The conductor stem can be turned from a metal rod as a one-piece; and / or the conductor stem can be silver plated; and / or the conductor stem can be polished.

[0016] The plurality of conductor branches can have a circular cross-section.

[0017] The plurality of conductor branches can have a rectangular cross-section.

[0018] The plurality of conductor branches can be cut or stamped from a metal plate as a one-piece; and / or the plurality of conductor branches can be silver plated; and / or the plurality of conductor branches can be polished.

[0019] One or more of the plurality of conductor branches can extend radially in a straight manner; and / or one or more of the plurality of conductor branches can extend radially in a curved or bent manner.

[0020] The radio frequency power divider-combiner can further comprise an outer conductor comprising: a trace receiving metal plate extending parallel to a reference plane; a trace covering metal plate extending parallel to the reference plane; and a stem receiving metal piece extending perpendicular to the reference plane.

[0021] The trace receiving metal plate can comprise a substrate of a heat sink; and / or the trace receiving metal plate can have a plurality of recessed channels corresponding to the plurality of conductor branches; and / or the plurality of recessed channels can have a stepped cross-section; and / or the plurality of recessed channels can be milled from the trace receiving metal plate; and / or the trace receiving metal plate can have a through hole aligned with an extension direction of the conductor stem; and / or the trace covering metal plate can have a through hole corresponding to a radial end of the plurality of conductor branches; and / or the trace covering metal plate can have a blind recess configured to accommodate a surface mount circuit element of a flip-chip mounted circuit board; and / or the blind recess can be milled from the trace covering metal plate; and / or the stem receiving metal piece can have a through hole aligned with an extension direction of the conductor stem; and / or the stem receiving metal piece can have an access opening aligned with an extension direction of the conductor stem, the access opening configured to accommodate a tuning element; and / or the through hole of the stem receiving metal piece can have a stepped cross-section.

[0022] Therefore, the through hole can have a straight (constant) cross-section, but alternatively, it can have a stepped cross-section that matches the stepped cross-section of the conductor backbone 2 on a portion or its entire extension. Thus, one or both of the through hole and the inner wall of the conductor backbone 2 can have a stepped cross-section.

[0023] The radio frequency power divider-combiner may also include multiple holding support elements configured to space and electrically isolate the internal and external conductors from each other.

[0024] Multiple retaining support elements can be made of either polytetrafluoroethylene (PTFE) or polyetheretherketone (PEEK) fluororesin alloy.

[0025] Multiple conductor branches may include corresponding input terminals at their respective radial ends, and the corresponding input terminals include the following connection devices: solder pads and plug connectors.

[0026] The RF power divider-combiner may also include an output connector; and one or more of the following: a connection between the radial end of the conductor trunk and the output connector; and an interchangeable RF filter between the radial end of the conductor trunk and the output connector.

[0027] According to a second aspect, an apparatus is provided comprising a radio frequency power split-combiner of the first aspect; and a circuit board configured for flip-mounting on the radio frequency power split-combiner.

[0028] Radio frequency power distribution - combiners and circuit boards can have corresponding interconnections. Attached Figure Description

[0029] The above aspects and implementations will now be explained with reference to the accompanying drawings, wherein the same or similar reference numerals denote the same or similar elements.

[0030] The accompanying drawings should be considered schematic representations, and the elements shown are not necessarily shown to scale. Rather, the various elements are shown such that their function and overall purpose will become apparent to those skilled in the art.

[0031] Figure 1 A perspective view of the internal conductors of an N-channel radio frequency power distribution-combiner according to the present invention is shown;

[0032] Figures 2-5 A top view of various conductor branches of the N-channel radio frequency power distribution-combiner according to the present invention is shown;

[0033] Figure 6 The following diagram illustrates the insertion into the trace receiving metal plate 10 according to the present invention. Figure 5 A top view of the conductor branch;

[0034] Figure 7 A cross-sectional view of a radial end of an N-way radio frequency power divider-combiner according to the present application is shown;

[0035] Figures 8-9 A cross-sectional view of a radial end of an N-way radio frequency power divider-combiner according to the present application is shown; and

[0036] Figure 10 A top view and a cross-sectional view of an arrangement of a radio frequency power divider-combiner and a plurality of circuit boards according to the present application is shown. DETAILED DESCRIPTION

[0037] In the following description, reference is made to the accompanying drawings which form a part hereof, and which show, by way of illustration, specific aspects in which implementations of the present application can be

[0038] For example, it shall be understood that disclosure in relation to a described method can also apply to a corresponding device or system configured to carry out the method, and vice versa. For example, if one or more specific method steps are described, a corresponding device can include one or more units (e.g. functional units) to perform the described one or more method steps (e.g. one unit performing the one or more steps, or a plurality of units each performing one or more of the plurality of steps), even if such one or more units are not explicitly described or illustrated in the figures. On the other hand, for example, if a specific device is described based on one or more units (e.g. functional units), a corresponding method can include a step to perform the functionality of this one or more units (e.g. one step performing the functionality of one or more units, or a plurality of steps each performing the functionality of one or more of a plurality of units), even if such one or more steps are not explicitly described or illustrated in the figures. Further, it shall be understood that features of the various example implementations and / or aspects described herein can be combined with each other, unless specifically noted otherwise.

[0039] Figure 1 A perspective view of the internal conductors 6 of an N-way radio frequency power divider-combiner according to the present application is shown.

[0040] The internal conductors 6 comprise a plurality (N) of conductor branches 1 extending radially from a common or central end 3 within a reference plane R.

[0041] The cross-section of the conductor branches can vary continuously or in a stepped manner. Thereby, the cross-section varies such that the profile tapers gradually from one end to the other end.

[0042] The conductor branches 1 are uniformly spaced in the circumferential direction and can comprise respective input terminals 19 at respective radial ends.

[0043] Typically, the plurality of conductor branches 1 can have similar cross sections, e.g. circular cross sections.

[0044] In the example of Fig. 1, the conductor branches 1 have a rectangular cross section. Thus, the conductor branches 1 can be cut or stamped from a metal plate as one piece. The conductor branches 1 can be silver plated and / or polished to minimize attenuation. Figure 1 In the example of Fig. 2, the conductor branches 1 have a stepped cross section increasing from the center end 3 towards the respective radial ends, thereby transforming the impedance of the respective conductor branch 1 and enabling a broadband matching.

[0045] Figure 1 In the example of Fig. 3, the conductor branches 1 have a stepped cross section decreasing from the center end 3 towards the respective radial ends, thereby transforming the impedance of the respective conductor branch 1 and enabling a broadband matching.

[0046] Typically, one or more of the plurality of conductor branches 1 can radially extend in a straight manner, and / or one or more of the plurality of conductor branches 1 can radially extend in a curved or bent manner, to optimize the position arrangement of the respective input terminal 19 at the respective radial end.

[0047] If the conductor branches 1 are similarly curved or bent (e.g. same bending angle, same structure), the bending direction is electrically irrelevant, so that the power balance between the conductor branches 1 is not affected. A slight deviation from strict symmetry can lead to an acceptable cumulative error.

[0048] Figures 1-2 The example of Fig. 4 comprises one straight conductor branch 1 and two bent conductor branches 1.

[0049] Figures 3-4 The example of Fig. 5 comprises three bent conductor branches 1.

[0050] Figure 5 The example of Fig. 6 comprises three straight conductor branches 1.

[0051] Back to Fig. 1, Figure 1 the inner conductor 6 further comprises a conductor trunk 2 of stepped cross section extending from the center end 3 perpendicular to the reference plane R.

[0052] The conductor trunk 2 can be turned from a metal rod as one piece; and / or the conductor trunk 2 can be silver plated; and / or the conductor trunk 2 can be polished.

[0053] In particular, the conductor trunk 2 and the plurality of conductor branches 1 can be threadedly fastened at the center end 3.

[0054] The radio frequency power dividing-combining device can further comprise an outer conductor 9 as explained next.

[0055] Figure 6 ​A top view of a conductor branch 1 inserted into a trace receiving metal plate 10 according to the present application is shown. Figure 5 A top view of a conductor branch 1 inserted into a trace receiving metal plate 10 according to the present application is shown.

[0056] The trace receiving metal plate 10 can have a plurality (N) of groove channels corresponding to the plurality of conductor branches 1 and can form part of the outer conductor 9 of a radio frequency power divider-combiner and extend parallel to the reference plane R.

[0057] In the example of Figure 6 The groove channels have a straight cross section, but they can also have a stepped cross section corresponding to the stepped cross section of the conductor branches 1.

[0058] In particular, the plurality of groove channels can be milled from the trace receiving metal plate 10, which can in particular comprise a base plate of the heat sink.

[0059] The trace receiving metal plate 10 can further comprise a through hole (at the central end 3) aligned with the extension direction of the conductor trunk 2.

[0060] The outer conductor 9 can further comprise a trunk receiving metal piece 15 extending perpendicular to the reference plane R, which will be explained below.

[0061] Figure 7 A cross-sectional view of an N-way radio frequency power divider-combiner according to the present application is shown.

[0062] The trunk receiving metal piece 15 can be dimensioned such that the cross section of the metal piece 15 hinders the air flow in the direction of the heat sink fins in the least possible way.

[0063] The trunk receiving metal piece 15 can have a through hole aligned with the extension direction of the conductor trunk 2, thereby forming a coaxial transmission line therewith. The air in the gap 14 serves as dielectric, but any other suitable material can be used according to its dielectric constant, such as Teflon, PEEK.

[0064] In the example of Figure 7 The through hole has a straight (constant) cross section, but it can alternatively present a stepped cross section matching the stepped cross section of the conductor trunk 2 over part or its entire extension. Thus, one or both of the inner wall of the through hole and the inner wall of the conductor trunk 2 can present a stepped cross section.

[0065] Furthermore, the trunk receiving metal piece 15 can have an access opening aligned with the extension direction of the conductor trunk 2. Said access opening can be configured to accommodate a tuning element 27.

[0066] The radio frequency power dividing-combining device can further comprise a plurality of holding support elements 7 configured to mutually space and electrically isolate the inner conductors 6 and the outer conductor 9.

[0067] In particular, the plurality of holding support elements 7, 24, 26 can be made of one of polytetrafluoroethylene (PTFE), polyether ether ketone (PEEK) fluororesin alloy, thereby maximizing the electrical isolation and minimizing the attenuation.

[0068] The radio frequency power dividing-combining device can further comprise an output connector 17, in particular a standard coaxial plug connector for up to 20 GHz, and a small connector or a hollow conductor / waveguide for above 20 GHz. At such high frequencies, the hollow conductor / waveguide enables a higher power transmission at the expense of bandwidth.

[0069] In Figure 7 The connection 18 can be configured to implement part of the required impedance transformation between the central terminal 3 and the output connector 17 (i.e. an extension of the conductor stem 2). Alternatively, the connection 18 can comprise a harmonic filter. Alternatively, the connection 18 can form part of a directional coupler or a lightning protection device or a customer-specific RF filter. Alternatively, an interchangeable, customer-specific RF filter can also be arranged between the radial end 16 of the conductor stem 2 and the output connector 17.

[0070] The outer conductor 9 can further comprise a trace covering metal sheet 11 extending parallel to the reference plane R, which will be explained below.

[0071] Figures 8-9 A cross-sectional view of a radial end of an N-way radio frequency power dividing-combining device according to the present application is shown.

[0072] As previously mentioned, the conductor branches 1 can comprise respective input terminals 19 at the respective radial ends.

[0073] The trace covering metal sheet 11 can have through-holes 23 corresponding to the radial ends of the plurality of conductor branches 1.

[0074] The respective input terminals 19 can in particular comprise connection means: pads and (female / male) plug connectors 20 configured to cooperate with corresponding (male / female) plug connectors 21 of the above-mentioned reversibly mounted circuit board 8. For example, the (female / male) plug connectors 20 can protrude perpendicular to the reference plane R, the respective (male / female) plug connectors 21 can also protrude perpendicular to the reference plane R and be automatically assembled / installed based on (reflow) soldering in vias.

[0075] The circuit board 8 can in particular comprise amplifier elements / circuits (MIC).

[0076] Said plug connections 20, 21 minimize signal path / attenuation, enabling arbitrary orientation of the flip-mounted circuit board 8 with respect to the respective conductor branch 1 and also arbitrary selection of the impedance level when transferring signals to the radio frequency power distribution-combiner.

[0077] The radio frequency power distribution-combiner can also comprise a plurality of holding support elements 7, 24, 26 configured to mutually space and electrically isolate the inner conductor 6, 1 from the outer conductors 9, 10, 11, thereby forming stripline transmission lines with them.

[0078] The holding support elements 24 can comprise isolation spacers corresponding to the penetration holes 23 of the stepped cross-section of the trace covering metal plate 11, so that the isolation spacers cannot be forced through said plate 11. The holding support elements 24 can also be configured to define a spacing between said plate 11 and the respective conductive branch 1.

[0079] The trace covering metal plate 11 can also have blind recesses 12 configured to house surface mounted circuit elements 13 of the flip-mounted circuit board 8, thereby enabling deployment of double-sided circuit boards 8 and shielding the circuit elements 13 with respect to other elements of the radio frequency power distribution-combiner or the circuit board 8. In particular, the blind recesses 12 can be milled from the trace covering metal plate 11.

[0080] Alternatively, the trace covering metal plate 11 can be formed by a ground plane on the flat side of the single-sided circuit board 8.

[0081] Figure 10 A top view and cross-sectional view of the device of the radio frequency power distribution-combiner and a plurality of circuit boards 8 according to the present application are shown.

[0082] In particular, the radio frequency power distribution-combiner and the circuit board 8 can have mutually corresponding connection means 20, 21, for example (male / female) plug connectors, as previously described.

[0083] It should be noted that the flip-mounted circuit board 8 is oriented arbitrarily with respect to the respective conductor branch 1, for example perpendicular to the fins of the heat sink, distributing the circuit board 8 on the heat sink.

[0084] Preferably, the circuit board 8 is fixed / tightened in this orientation to avoid shear forces acting on the connection means 20, 21.

[0085] It should be noted that the proposed radio frequency power distribution-combiner does not have the typical isolation resistor of the Wilkinson coupler, thus avoiding excessive attenuation.

[0086] The radio frequency power distribution-combiner is mainly described as a combiner. The deployment as a power distributor only makes sense for very high powers.

[0087] RF power dividing-combiners are particularly useful for N > 2, since for N = 2 there exists a planar solution for theoretically perfect power addition.

[0088] The application has been described in relation to various implementations, by way of example only. Other variations and implementations can be understood and effected by persons skilled in the art from a study of the drawings, the disclosure and the independent claims. The word "comprising" does not exclude other elements or steps, and the word "an" or "a" does not exclude a plurality. A single unit or other unit can fulfil the functions of several entities or items recited in the claims. The mere fact that certain measures are recited in mutually different dependent claims does not indicate that a combination of these measures cannot be used to advantage. A computer program can be stored / distributed on a suitable medium, such as an optical storage medium or a solid-state storage medium supplied together with or as part of other hardware, but can also be distributed in other forms, such as via the Internet or other wired or wireless telecommunication systems.

Claims

1. An N-way radio frequency power divider-combiner, comprising: - an inner conductor (6) comprising: - a plurality (N) of conductor branches (1) having varying, e.g. stepped, cross sections and extending radially and circumferentially uniformly spaced from a center end (3) within a reference plane (R); and - a stepped cross section conductor trunk (2) extending from the center end (3) perpendicular to the reference plane (R).

2. The radio frequency power divider-combiner according to claim 1, wherein - the conductor trunk (2) and the plurality of conductor branches (1) are fastened at the center end (3).

3. The radio frequency power divider-combiner according to claim 1 or 2, wherein - the conductor trunk (2) is turned from a metal rod in one piece; and / or - the conductor trunk (2) is silver plated; and / or - the conductor trunk (2) is polished.

4. The radio frequency power divider-combiner according to any one of claims 1 to 3, wherein - the plurality of conductor branches (1) have circular cross sections, rectangular cross sections, or combinations thereof.

5. The radio frequency power divider-combiner according to claim 4, wherein - the plurality of conductor branches (1) are cut or stamped from a metal sheet in one piece; and / or - the plurality of conductor branches (1) are silver plated; and / or - the plurality of conductor branches (1) are polished.

6. The radio frequency power divider-combiner according to any one of claims 1 to 5, wherein - one or more of the plurality of conductor branches (1) extend radially in a straight manner; and / or - one or more of the plurality of conductor branches (1) extend radially in a curved or bent manner.

7. The radio frequency power divider-combiner according to any one of claims 1 to 6, further comprising: - an outer conductor (9) comprising: - a trace receiving metal sheet (10) extending parallel to the reference plane (R); - a trace covering metal sheet (11) extending parallel to the reference plane (R); and - a trunk receiving metal piece (15) extending perpendicular to the reference plane (R).

8. The radio frequency power divider-combiner according to claim 7, wherein - the trace receiving metal sheet (10) comprises a heat sink base plate; and / or - the trace receiving metal sheet (10) has a plurality (N) of recessed channels corresponding to the plurality of conductor branches (1); and / or - the plurality of recessed channels have stepped cross sections; and / or - the plurality of recessed channels are milled from the trace receiving metal sheet (10); and / or - the trace receiving metal sheet (10) has a through hole aligned with an extension direction of the conductor trunk (2); and / or - the trace covering metal sheet (11) has through holes (23) corresponding to radial ends of the plurality of conductor branches (1); and / or - the trace covering metal sheet (11) has blind recesses (12) configured to accommodate surface mount circuit elements (13) of a flip mountable circuit board (8); and / or - the blind recesses (12) are milled from the track covering metal sheet (11); and / or - the trunk receiving metal piece (15) has a through hole aligned with the extension direction of the conductor trunk (2); and / or - the trunk receiving metal piece (15) has an access opening aligned with the extension direction of the conductor trunk (2), the access opening being configured to house a tuning element (27); and / or - the through hole of the trunk receiving metal piece (15) has a stepped cross section.

9. The radio frequency power dividing-combining device according to claim 7 or 8, further comprising: - a plurality of holding support elements (7, 24, 26) configured to mutually space and electrically isolate the inner conductor (6) and the outer conductor (9).

10. The radio frequency power dividing-combining device according to claim 9, wherein - the plurality of holding support elements (7, 24, 26) are made of one of the following: - polytetrafluoroethylene (PTFE), and - polyether ether ketone (PEEK) fluororesin alloy.

11. The radio frequency power dividing-combining device according to any one of claims 1 to 10, wherein - the plurality of conductor branches (1) comprise a respective input terminal (19) at each radial end, the respective input terminal (19) comprising connection means of the following: - a solder pad, and - a plug connector (20) or a contact element such as a pin fitted in an opening.

12. The radio frequency power dividing-combining device according to any one of claims 1 to 11, further comprising: - an output connector (17); and one or more of the following: - a connection piece (18) between a radial end (16) of the conductor trunk (2) and the output connector (17); and - an interchangeable radio frequency filter between a radial end (16) of the conductor trunk (2) and the output connector (17).

13. An apparatus comprising: - a radio frequency power dividing-combining device according to any one of claims 1 to 12; and - a circuit board (8) configured for flip-chip mounting on the radio frequency power dividing-combining device.

14. The apparatus according to claim 13, wherein - the radio frequency power dividing-combining device and the circuit board (8) have mutually corresponding connection means (20, 21).

15. The apparatus according to claim 14, wherein - the connection means (20, 21) are configured to be connected by means of a soldering process.

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