This application claims the benefit of German Application No. 102018105349.5, filed on Mar. 8, 2018, which application is hereby incorporated herein by reference.
This disclosure relates in general to devices having stripline sections.
Developments in the field of radiofrequency (or RF) applications, for example in the case of communications systems, are increasingly moving in the direction of smaller dimensions with simultaneously higher power and with the simultaneous requirement of satisfying larger bandwidths of the signals. In order to keep the spatial requirements of corresponding RF circuits compact, the degree of integration of the RF circuits is successively increased. This also applies to the dimensions of RF circuits that comprise waveguides, typically consisting of two transmission lines, wherein the two transmission lines are often configured as what are called striplines.
In order to keep the dimensions of these striplines compact, for example to keep the requirements in terms of the amount of surface on a circuit board low, striplines are often configured in a snaking form, which is often also referred to as being meandering. This snaking allows a more compact arrangement than a straight stripline configuration, but, as a result of the close spatial arrangement of stripline sections, electromagnetic coupling of different, for example adjacent, stripline sections may occur, which may result in undesired effects. For example, it is possible for this type of electromagnetic coupling to change the effective electrical length of the transmission line for certain signals, and losses may increase in the transmission line.
These possible negative effects due to electromagnetic coupling are called “negative feedback” between stripline sections.
According to one exemplary embodiment, a device is provided that comprises at least one electrically conductive structure and at least one stripline. The stripline comprises a multiplicity of stripline sections that are connected to one another in a series connection between a first terminal and a second terminal. A first subset of the stripline sections is arranged on a first side of the conductive structure and a second subset of the stripline sections is arranged on a second side of the conductive structure, wherein the second side is different from the first side. Furthermore, the at least one conductive connection is isolated from the at least one electrically conductive structure, wherein the first subset of the stripline sections is arranged in a first arrangement and/or the second subset of the stripline sections is arranged in a second arrangement, such that a signal propagating from the first terminal to the second terminal has coupling integrated over the first arrangement and/or second arrangement, which coupling is positive.
Various exemplary embodiments are described in detail below with reference to the appended drawings. These exemplary embodiments should be considered merely as an example and should not be understood to be restrictive. Byway of example, in other exemplary embodiments, some of the described features or components may be omitted and/or replaced with alternative features or components. Features or components of various exemplary embodiments may be combined in order to form further exemplary embodiments. Variations and modifications described with regard to one exemplary embodiment may also be applied to other exemplary embodiments. Furthermore, features or components other than those described or shown may be provided, for example in conventional transmission line circuits or circuits used in connection with radiofrequency (RF) technology. By way of example, RF technology is used in the frequency range of fifth generation (5G) mobile radio networks.
Direct connections or couplings shown in the drawings or described below, that is to say electrical connections or couplings without interposed elements (for example simple metal conductive tracks) may also be produced by way of an indirect connection or coupling, that is to say a connection or coupling that comprises one or more additional interposed elements, and vice versa, as long as the general function of the connection or coupling, for example providing a voltage, providing a current, guiding an electromagnetic wave or providing a control signal, is substantially retained.
In the figures, identical reference symbols indicate identical or similar elements. The figures are schematic representations of various exemplary embodiments. Elements that are illustrated in the figures are not necessarily illustrated true to scale. Rather, the various elements that are illustrated in the figures are reproduced in such a way that their function and general purpose become clear to a person skilled in the art.
Numerical values cited in connection with exemplary embodiments, for example in connection with simulation curves, serve merely for the purpose of explanation. Numerical values and profile forms of curves should not be interpreted as being restrictive and depend on the choice of the parameters.
Waveguides, for example RF waveguides, may be implemented in various ways. By way of example, waveguides may be implemented by way of two striplines. Striplines may be conductive track sections. Conductive track sections illustrated as simple rectangular conductive track sections may have more complex shapes, as is known for striplines in RF technology, such that for example capacitive and inductive effects are able to be created by suitably dimensioned strips and, through suitable shaping, filter structures or the like are also able to be produced.
Striplines may be configured so as to run in planes, but also over curved surfaces.
Striplines may be used to implement waveguides. To this end, a first conductor element may comprise one or more striplines. This stripline may be applied to a dielectric. A second conductor element may be configured as a stripline, which may be configured for example as a conductive surface. This second conductor element may be at a reference potential, which may be a ground potential, and be isolated from the first conductor element. Further examples of striplines are described in connection with
The waveguide that is shown is suitable for transmitting a signal, for example an RF signal, from a first terminal 11 to a second terminal 12 as shown in
To achieve desired transmission properties for HF signals between the first terminal 11 and the second terminal 12, it may be necessary to route the stripline 10 over a relatively long path, which may go against the requirement of compactness for some cases of application.
The striplines, for example the stripline 10 and the conductive structure 14, may be striplines in general, but also within the meaning of the term “microstrip”, as an arrangement on the surface of an insulating plate, for example a ceramic material. The striplines may be configured symmetrically but also asymmetrically, for example in the form of what is called an “offset stripline.”
Surfaces or planes that are discussed below may be implemented in the form of multilayer substrates. In the case of multilayer substrates, layers other than those shown in the exemplary embodiments may be used. By way of example, additional dielectric layers and metal layers may be used. These metal layers may be used for example to shield the exemplary embodiments.
In the context of this description, electromagnetic coupling or counter-induction is understood to mean the mutual electromagnetic influencing of two or more spatially adjacent conductive components due to electromagnetic induction. In terms of quantity, the electromagnetic coupling or counter-induction may be described with the aid of coupling coefficients.
By way of example, electromagnetic coupling may also exist between stripline sections. If these striplines or else also other conductive structures are used to transmit signals, the interaction due to the electromagnetic coupling of individual sections of the structures may influence the waveguide properties of the conductively connected overall structure. Depending on the type of electromagnetic coupling, this coupling may have an advantageous effect with regard to the desired routing properties for the RF signals. Accordingly, positive coupling then exists if signals are amplified due to the coupling interaction, which leads to a situation whereby the attenuation of a signal in a matching path comprising series-connected stripline sections is reduced in comparison with a matching path configured so as to be straight. Accordingly, negative coupling (which is disadvantageous for some applications) then exists if the interaction of the signals leads to weakening, which leads to a situation whereby the attenuation of a matching path is increased in comparison with a matching path configured so as to be straight. For an arrangement of stripline sections that are connected in series, an integrated coupling may be determined, wherein the coupling coefficients for the various regions are discretely summed or integrated in order to determine an integrated coupling of a signal. The coupling, integrated over an arrangement of stripline sections, may be determined for example on the basis of the geometry by way of numerical methods. In this case, the integration may be numerically approximated.
A direction, in connection with this description and unless stated otherwise, is understood to mean a vector value. Directions may thus differ by 180°, for example. If the underlying surface with respect to which the direction is given is a plane, angular relationships between the directions may be determined by way of calculations in Cartesian coordinates; otherwise, conformal maps such as for example Mercator projections may be used.
The term “substantially parallel” is understood to mean that two directions deviate from one another by a maximum of ±20°, for example by a maximum of ±15°, for example by a maximum of ±10°, for example by a maximum of ±5°, for example in the context of the manufacturing tolerance of the respective manufacturing method. If a direction of a curved form or of a form having a complex profile is involved, then the underlying direction should be determined using the start and end point of the corresponding structure. By way of example, structures may have a direction in that they follow an underlying direction in substructures that are configured in steps. To this end, structures may be composed for example of substructures that are each arranged at an angle of 90° with respect to one another, for example, and extend over various lengths of the respective substructures taken together in any desired predefined direction. In the case of substructures that are configured in steps, a parallel profile may for example also be achieved by the individual substructures, or at least some of the substructures, being arranged parallel to one another.
Due to the positive feedback between the various stripline sections 203, in some embodiments, it may be possible to use wider and at the same time shorter striplines, in comparison with the stripline dimensions in the case of an uncoupled transmission line. As a result, such a structure may have lower losses and at the same time be suitable for more compact structures due to the changed electrical length.
The stripline 33 connects a first terminal 31 to a second terminal 32, as shown in
These interactions may lead to disadvantageous properties as the waves flow in different directions. To compensate this effect and to have the same equivalent impedance and electrical length as a waveguide guided in a straight line, it may be necessary to modify the physical properties of the transmission line. The result of the design may be thinner striplines 33 having a longer overall length, which may in turn lead to higher losses in the line.
In the implementation shown in
The stripline sections 403 and 404, in the examples of
In some exemplary embodiments, the stripline sections have properties of the stripline 33 outlined in connection with
At least one conductive connection 407, 408 is provided, which are produced by way of a multiplicity of connecting elements 407, 408 in the exemplary embodiment that is shown and connect the stripline sections of the first 403, 404 and second subset of the stripline sections 406 in series with one another. At the same time, the multiplicity of connecting elements 407, 408 are electrically isolated from the at least one conductive structure 405.
The stripline sections 403, 404 disposed on the first surface F1 are arranged in a first direction R1, and the at least one second conductor section 406 disposed on a third surface F3 is arranged in a second direction R2 different from the first direction R1.
The second direction may in this case differ from the first direction by (180±90)°, or by (180±45)°, or by (180±20)°, for example be roughly opposing.
As a result of this difference in directions described above, a situation is able to be achieved whereby the stripline sections 403, 404 on the first surface F1 each have positive coupling with respect to one another, and, due to the at least one conductive structure 405, there is virtually no coupling with the at least one second conductor section 406, and a compact structure is able to be produced.
In various exemplary embodiments, only the outer surface Fa, only the fourth surface F4, or both the outer surface Fa and the fourth surface F4 may be present.
In the exemplary embodiments in which the outer surface Fa is present, an outer volume Va, which is delimited by the first surface F1 and the outer surface Fa, is filled with a fourth dielectric material having a permittivity ε4. In addition, the second at least one conductive structure 409 may be coupled to the at least one conductive structure on the first surface F1.
In the exemplary embodiments in which the fourth surface (F4) is present, a third volume (V3), which is delimited by the third surface (F3) and the fourth surface (F4), is filled with a third dielectric material having a permittivity ε3.
In addition, the third at least one conductive structure (410) may be coupled to the at least one conductive structure on the first surface (F1).
In this case, one possible implementation according to various exemplary embodiments in a plurality of planes is illustrated for example on the basis of a multilayer substrate.
According to this implementation, a stripline 500 is provided, comprising a multiplicity of series-connected stripline sections 502, 504 between a first terminal 501 and a second terminal 509 as shown in
The at least one electrically conductive structure 505 is electrically isolated from the multiplicity of stripline sections 502, 504.
A first dielectric 507 is situated between the first plane E1 and the second plane E2, and a second dielectric 508 is situated between the second plane E2 and the third plane E3 as shown in
The stripline sections 502 are connected in series between the first plane E1 and the third plane E3 by way of a plurality of conductive connections 503, configured as connecting elements 503 in the exemplary embodiment, and electrically isolated from the at least one electrically conductive structure 505.
In the examples illustrated, the stripline sections are configured so as to be straight. In other exemplary embodiments, the stripline sections 504, 502 may be configured so as not to be straight. By way of example, curved or undulating profiles may be used or stepped profiles may be produced using straight and/or curved elements that are arranged alternately at one or more angles with respect to one another. A common feature of the exemplary embodiments is that the coupling between the stripline sections running substantially in a first direction R1 is positive coupling. This may likewise be the case for the stripline sections running substantially in a second direction R2.
In the implementation that is described, the at least one conductive structure 505 in the second plane E2 is used both by the stripline sections in the first plane E1 and by the stripline sections in the second plane E2 as a second transmission line, as a ground surface. This may have the advantage of a simplified configuration and of a reduced requirement in terms of material. It is also possible, however, to use a plurality of planes having conductive structures that are coupled to a reference potential, to ground in some exemplary embodiments.
These implementations, according to the above exemplary embodiments, may have the advantage that the wave guidance is able to be implemented on a compact surface. The striplines 502, 504 may in each case also be configured as microstrip lines.
The properties of the positive feedback between the striplines 502 and/or 504, which are able to be described mathematically for example with the aid of coupling coefficients in each case between individual striplines 502 and/or 504, but may also be calculated in a more complex manner, for example byway of finite element methods, may be influenced by the geometric form of the individual striplines 502, 504, for example by modifying the dimensions such as length, width and height and further parameters that define the form of the stripline, such as for example the shape, which may be for example a straight, rectangular shape, a curved, a bent or a curvilinear shape or combinations of these shapes, and by the arrangements of the striplines 502 and/or 504 with respect to one another, for example the distance between the individual striplines 502 and/or 504. These properties may be designed separately for the striplines 502 and 504.
These coupling properties may be optimized for particular frequency ranges and/or signal forms in a targeted manner. For individual arrangements of stripline sections that are able to be connected in series, integrated coupling may be determined as a coupling property of the overall arrangement between a first and a second point, wherein the first and the second point may be determined for example between a first terminal and a second terminal, or else between a terminal and a connecting element.
The loss is in each case shown as a function of frequency for various variants of transmission lines on an exemplary substrate. In each case λ/4 transmission lines having a center frequency of roughly 3.6 GHz are shown.
A first curve 601 (
A second curve 602 (
A third curve 603 (
In this case, it should be emphasized once again that the specified curves serve merely as an example with regard to both their profile forms and numerical values; depending on the choice of the distances between the conductive tracks, the profile forms may vary significantly. A greater distance between the conductive tracks thus leads to a smaller effect of the coupling, whereas a smaller distance between the conductive tracks leads to greater coupling and thus to a greater effect. It is thus also possible, in some exemplary embodiments, depending on the specific implementation, for the effects to occur to a greater or also to a lesser extent. By way of example, by changing these parameters, the system is able to be designed and optimized in line with the requirement for the specific case of application.
According to the exemplary embodiments that were outlined in connection with
Both the stripline sections 807 and the stripline sections 808 are arranged in a first direction R1. If a signal is then transmitted in one of the two transmission lines, for example the first transmission line and the corresponding line sections 807, 808, then there is electromagnetic coupling to the other transmission line, and thus for example to the second line sections 808.
According to the same principle, a second subset of stripline sections 809 may have positive coupling with a fourth subset of stripline sections 810.
Using the arrangement of the line sections, it is possible to utilize the described coupling to amplify the coupling effects. By way of example, the second line section 806 may at the same time have coupling to the two line sections 805 of the first transmission line, wherein, due to the adjacent arrangement of the line sections, the coupling of the two line sections 805 to the line section 806 is amplified.
According to these exemplary embodiments, it is possible to provide coupling between two adjacent transmission lines. This may be used for example in the case of application of a directional coupler.
In this case, the stripline sections, arranged in the first plane E1, of the second multiplicity of stripline sections 901 are oriented in a first direction R1, and the stripline sections, arranged in the third plane E3, of the second multiplicity of stripline sections 902 are arranged in a second direction R2. The directions R1 and R2 in this case correspond to the directions R1 and R2 of
As outlined in connection with
At the same time as shown here, but also as an alternative, the stripline sections, arranged in the third plane E3, of the second multiplicity of stripline sections 902 may have coupling with the stripline sections 406, likewise arranged in the third plane E3.
As a result of the described coupling between the transmission line that connects the first terminal 401 to the second terminal 402 and the transmission line that connects the third terminal 903 to the fourth terminal 904, the device may act as a directional coupler.
The directions R1 and R2, the number of substantially parallel-running tracks of the stripline sections 403, 404, 901, 406, 902 (shown for example in
Both
In the present example, the spiral shape is produced by way of straight sections that have curves of substantially 90°.
Other implementations of a spiral-shaped profile, for example circular or elliptical basic forms, wherein the radius of the underlying form may change as a function of the length of the conductor section, are likewise possible. It is likewise possible to approximate a basic form using straight sections, for example a circular basic form as a polygon. A spiral may also have different variants in different regions, for example use a circular basic form in one region and use a polygon as underlying form in another region.
The stripline 1002 comprises a first subset of conductor sections 1002a that are situated on the first side of an electrically conductive structure 1010 (
A conductive connection 1005 (
The spiral region 1004 may have a distance 1007, defined as the shortest distance between the spiral region 1004 and the at least one conductive connection 1005.
In the exemplary embodiments shown in
As shown in
Due to the conductive structure 1010, both spiral regions may be considered independently of one another, with the exception of the connection, provided by the at least one conductive connection 1005, in the middle of spiral-shaped arrangement 1006, wherein the at least one conductive connection, including outside the middle of spiral-shaped arrangement 1006, may lie for example in the spiral region 1004, for example may lie outside the spiral region 1004.
Although specific exemplary embodiments have been illustrated and described in this description, those skilled in the art will recognize that a multiplicity of alternative and/or equivalent implementations may be selected as a substitute for the specific exemplary embodiments that are disclosed and described in this description, without departing from the scope of the disclosed invention. This application is intended to cover all adaptations or variations of the specific exemplary embodiments that are discussed here. It is therefore intended for this invention to be restricted only by the claims and the equivalents of the claims.
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10 2018 105 349.5 | Mar 2018 | DE | national |
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20190280360 A1 | Sep 2019 | US |