EP2533354B1 - Device for coupling an HF signal along a signal path - Google Patents

Description

Technical area

The invention relates to a device for coupling, ie input or output, of an RF signal along a signal path. Furthermore, a device for coupling at least two RF signals is described, each of which abuts different transmission channels, on a common transmission line,
wherein each transmission channel is assigned a bandpass filter, via which the respective transmission channel is coupled to the transmission line.

State of the art

Multiswitches, so-called "manifold combiners", are used in the broadcasting area for the interconnection of two or more transmission channels to a common antenna line. It is important to interconnect the transmitter so that they do not disturb each other as possible. This so-called decoupling is the more difficult the less the frequency spacing of the transmission channels. At low frequency channel distances or even with tunable transmission frequencies filter switches are usually used, in which the decoupling via each of the transmitters downstream narrow-band bandpass filter. These can also serve to suppress spurious emissions and thus as an integrated mask filter. The filter outputs must be interconnected via appropriate matching networks in such a way that the best possible adaptation in the operating channels prevails. Outside the operating channels, however, there is a mismatch, so that RF signals with frequencies outside the operating channel are largely reflected and thus do not propagate or at least strongly attenuated towards the antenna.

Such matching networks are widely implemented by means of pipe lines, wherein the line lengths are each dimensioned such that the useful signals propagate as exclusively as possible in the antenna direction.

To explain a known Manifoldstruktur be on Fig. 3 referenced, in which the filters F1 to Fn are inductively coupled to the common antenna line A. The antenna line A is here each looped through the individual filters F1 to Fn, ie there is the output side to each of the filters in each case an input and an output port B _a, B _from the antenna line. The filters therefore have three ports or connections, ie said input and output port B _a, B _from the antenna line and the filter input F _a on which the respective transmitting signal is fed for filtering. The antenna line A is short-circuited K on one side and terminates on the output side with an antenna output AT.

Out US 2009/0045887 A1 is a directional coupler with two decoupling branches known whose electrical length is shorter than λ / 4. A good directivity of the arrangement is achieved in that the Auskoppelzweige are electrically connected together at one end. In addition, one of the decoupling branches is terminated at the other end with a tunable impedance, whereas the other decoupling branch remains open.

Out DE 695 15 815 T2 is a Mehrsendeweiche with a summing network of lines, connecting devices (T-branches) and a stub device is known in which the adjustment is done by changing the electrical length of the stub by means of a supplied control signal.

The RU 2 410 803 C1 discloses a simple coupling device with which a coaxial line can be coupled to a main coaxial cable. For this purpose, a blind hole is introduced in the radial direction in the Hauptkoaxialkabel, which extends into the inner conductor. One end of the coaxial line to be coupled is guided with its inner conductor and its dielectric in the blind hole.

Out US 607,200 a device for decoupling electromagnetic signals from a coaxial resonator is known in which the decoupling takes place via a disc element, which is brought via a introduced in the outer surface of the outer conductor bore in the vicinity of the inner conductor. The coupling factor is adjustable over the distance to the inner conductor.

The US 2007/0252661 A1 shows a manifold manifold for multiple channels, each channel is connected via a bandpass filter to the antenna cable. The antenna cable is short-circuited on one side.

Out US 2003/0003814 A1 a device for the variable splitting or merging of high-frequency power is known, in which a branch line branches off from a branch point lying between the input port and the first output port to a second output port. By a combination of variable coupling capacitances and a variable spur line, which are varied with a common operating element, a variable power distribution is realized without changing the impedance at the input gate.

Presentation of the invention

The invention has for its object to provide a device for coupling an RF signal along a signal path, which is designed such that possibly occurring between the respective filter and the coupling point along the signal path natural resonances are at least in a frequency range outside the working Frequency range is. In addition, the coupling device for the coupling of different filter types alike be able to offer more flexible connection options for various types of filters in this way. Furthermore, a cost-effective device for coupling at least two RF signals to a common transmission line is to be specified, wherein the at least two RF signals each have a transmission channel is assigned, along each of which a bandpass filter is connected, which couples the respective transmission line to the signal path.
The solution of the problem underlying the invention is specified in claims 1 and 10. The concept of the invention advantageously further features are the subject of the dependent claims and the description with reference to the exemplary embodiments.
The solution of the object according to the invention is based on the idea of providing a capacitive coupling of an HF signal along a signal path, wherein the coupling capacitance is placed in the signal path.
According to the invention, a device is claimed for coupling an HF signal along a signal path, in which the signal path extends between a first and second coaxial RF connection structure, wherein the two coaxial RF connection structures each have an inner conductor electrically interconnected via a line structure and the line structure is capacitively coupled with an electrically conductive coupling structure, via which the RF signal can be coupled along the signal path. The line structure connects the two coaxial RF connection structures continuously with each other. A bore or opening oriented essentially transversely to the longitudinal extension of the line structure is introduced along the line structure, through which a first section of the coupling structure protrudes. The first section of the coupling structure and the line structure are spaced apart by means of an insulator. The RF signal can be capacitively coupled between the first section of the coupling structure and the line structure. The coupling capacity between the coupling structure and the line structure is constant.

In principle, the device is also quite suitable for decoupling of RF signals from the signal path and for forwarding via the coupling structure and an adjoining filter unit. Preferably, the device is suitable however, for coupling RF signals via the coupling structure into the signal path between the coaxial RF connection structures.

Furthermore, it has been recognized in accordance with the solution that the above coupling device can be used as the basic structure for the construction of a device for coupling at least two RF signals onto a common transmission line. Such a device is the subject of claim 10. Each of the at least two RF signals is applied to a transmission channel along which a respective bandpass filter is connected, which couples the respective transmission line to the signal path. According to the solution, for coupling in of the at least two RF signals to the common transmission line, in each case one coupling device is provided for each transmission line, wherein the coupling structure assigned to each coupling device capacitively couples to the bandpass filter of the respective transmission channel. Furthermore, in each case one RF connection structure per coupling device is HF-moderately connected or coupled to one another such that the line structures extending between the RF connection structures of both coupling devices and the RF connection structures RF-coupled with each other form the common transmission line.

Fig. 1

Schematisierte Darstellung einer lösungsgemäßen Vorrichtung zur Kopplung längs eines Signalpfads, kurz Kopplungsvorrichtung sowie

Fig. 2

Prinzipdarstellung einer Vorrichtung mit kapazitiver Einkopplung mehrerer HF-Signale längs einer Sendeleitung.

For a further description of both the inventive coupling device according to claim 1 and the device according to claim 10 reference is made in the following without limiting the general inventive concept to the respective concrete embodiments.

Fig. 1

Schematized representation of a device according to the invention for coupling along a signal path, in short coupling device and

Fig. 2

Schematic representation of a device with capacitive coupling of several RF signals along a transmission line.

Ways to carry out the invention, industrial usability

In the Fig. 1 The device shown schematically shows a coupling device for coupling an RF signal HF along a signal path SP which extends between a first and second coaxial RF connection structure 1, 2 of the coupling structure in the form of a line structure 5, the two inner conductors 3, 4 of the coaxial RF connection structures 1, 2 interconnected. Along the line structure 5 is an electrically conductive coupling structure 12 is capacitively coupled, via which the RF signal RF in the signal path SP on or auskoppelbar from this. The RF signal HF is provided in the case of a signal coupling into the signal path SP by a transmission line, not shown, which couples via a filter arrangement B to the coupling device via the coupling structure 12.

For ease of illustration, the RF terminal structures 1, 2 were shown only as rectangular symbols, as well as the indicated filter B, which is releasably fixedly attached via a suitable joint 19 to the housing 11 surrounding the coupling device. The housing 11 is further designed such that it can be opened in several places or has open or closable openings in order to allow a simplified assembly. Likewise, the inner conductors 3, 4 and the line structure 5 are shown schematically, i. Dimensions and configurations, in particular in the region of the transition from the inner conductor 3, 4 to the line structure 5 can deviate greatly from the geometry shown in the figure. The person skilled in the art will consider the dimensioning according to the requirements, e.g. Wavelength, power of the RF signals, characteristic impedance, coupling capacity, withstand voltage, etc.

The line structure 5 is preferably integrally formed for electrically connecting the inner conductors 3, 4 of the coaxial RF connection structures 1, 2. Thus, a bore or opening 13 oriented essentially transversely to the longitudinal extent of the line structure 5 is preferably located centrally of the line structure 5, through which hole a first section 6 of the coupling structure 12 projects. This first section 6 of the coupling structure 12 is at least partially radially surrounded by a sleeve-like, electrical insulator 7, which supports the entire coupling structure 12 mechanically self-supporting, preferably by means of fitting, and also the section 6 of the coupling structure 12 through the Sleeve wall thickness of the insulator 7 from the conductor structure 5 spaced at a fixed distance. This creates a capacitor structure in the form of a tube capacitor, whose capacitive coupling strength remains the same, even if the coupling structure 12 is displaced for purposes of capacitive adaptation to the external filter B in the longitudinal extent of the coupling structure 12, as will be explained below.

To avoid power losses during the transmission or transmission of the RF signals, the line structure 5 is preferably made of brass, copper, aluminum, silver or gold. Also conceivable would be a one-piece production of the line structure 5 made of copper, brass or aluminum with a surface coating of silver or gold or a similarly good electrical conductive metal.

Like the one in FIG. 1 shown embodiment, the first and second coaxial RF terminal structure 1, 2 are attached to the housing 11 each at a housing opening in the housing interior, the inner conductor 3, 4 of the RF terminal structures 1, 2 interconnected line structure 5 is introduced , The rod-cylindrical shaped first section 6 of the coupling structure 12 is located within the housing 11 and fits accurately within the hollow cylindrical insulator 7 such that the first portion 6 of the coupling structure 12 is both about its rod longitudinal axis 14 rotatable and longitudinally displaceable to the rod longitudinal axis 14. The rotation as well as the longitudinal displacement takes place with the aid of a rod-shaped or pin-shaped means 15, which is directly or indirectly engaged with the first section 6 of the coupling structure 12 and projects through the housing 11 to the outside through the housing wall 10. The set longitudinal displacement can be secured by means of appropriate securing means on or outside the housing.

Furthermore, the housing 11 has an opening 9 on a second housing wall 18 opposite the first housing wall 10, through which a second section 8 of the coupling structure 12, which is HF-moderately connected to the first section 6, projects.

On the second housing wall 18, a connecting structure 19 is further attached, to which an external RF assembly 20, for example. In the form of a filter B mechanically releasably fixed, from which an RF signal HF via the second section 8 in the coupling structure 12th and capacitive over the first portion 6 of the coupling structure 12 via the tube capacitor assembly in the line structure 5 can be coupled.

The second section 8 of the coupling structure 12 has at its end a plate-shaped or disk-shaped contour, which serves for the capacitive coupling to the external RF module 20. In order to optimize the external signal coupling between the coupling structure 12 and the external module, at least the longitudinal displacement of the coupling structure 12 is used by means of the rod-shaped means 15. It would also be conceivable to rotate the coupling structure 12 about the rod longitudinal axis 14, if, for example, the end plate or disk-shaped contour has a shape deviating from the rotational symmetry about the rod longitudinal axis 14.

The solution according to the charm of the coupling device is to be seen in particular in that the electrical coupling ratios and the geometric arrangement of the capacitive coupling region, which takes the form of a tubular capacitor structure in the embodiment, along the line structure 5, ie along the signal path SP, remain unchanged, and at the same time care is worn that a change, in terms of optimization, the coupling ratios for the coupling of an external module 20 can be made to the coupling device individually. Due to the compact design of the coupling device, the line lengths between the capacitive coupling region and the external modules can also be made as short as possible, resulting in advantages in the formation of natural resonances, which preferably form at short line lengths in frequency ranges that are outside the working frequency range , Due to the rotational and / or longitudinal displaceability of the coupling structure 12, different external assemblies can be attached to the coupling device. A storage of differently shaped coupling devices, as hitherto the case, thus eliminated. In addition, the solution according to coupling device is insensitive to temperature, as possibly occurring due to temperature Expansion effects, in particular in the area of the capacitive coupling region, which assumes the form of a tubular capacitor structure in the embodiment, due to the rotationally symmetrical formation around the rod longitudinal axis appear isotropically in appearance and thus compensate. In particular, a temperature-induced expansion of the insulator affects the coupling strength only slightly due to the geometry selected.

Alternatively to the in FIG. 1 illustrated embodiment in which the RF connection structures 1, 2 and the housing opening 9 on opposite housing walls are also any other mounting variants conceivable. For example, the RF connection structures 1, 2 and the opening 9 can be arranged on adjacent or identical housing walls. The person skilled in the art will select a suitable arrangement and modify the device accordingly.

In FIG. 2 is an embodiment of a device for coupling of at least two RF signals, here of n RF signals, HF1, HF2, ..., HFn shown on a common transmission line S. Such a device is also referred to as a multi-transmitter switch or manifold combination. The individual n RF signals are each separated from each other to individual transmission lines S1, S2, ... Sn, the capacitive coupled individually via bandpass filter B1 ... Bn to the common transmission line S. The common transmission line S, which typically represents an antenna line, is short-circuited on one side with a transmission line end 22, the opposite transmission line end 25 represents the antenna output AT.

The Einkoppelstellen O1, O2, ... On, at which the individual transmission lines S1, .... Sn capacitively coupled via the bandpass filters B1, B2, ..., Bn in the transmission line S, each have a line length distance to the one-sided short circuit K. which corresponds to an odd multiple of λi / 4, where λi corresponds to the wavelength of the RF signals along the ith transmission line. According to this, the individual line sections 22, 23, 24,... Are selected between the coupling-in points O1 and O2 or O2 and O3 etc. and the short circuit. The system can thus be extended as required, ie for each additional one to be coupled in Transmission channel is provided a further correspondingly dimensioned line piece, which forms part of the transmission line S.

The HF signals HF1, HF2,..., HFn, which can be assigned to the individual transmission lines S1, S2,..., Sn, are each detected by means of a coupling structure 21, which in FIG. 1 is explained in more detail, coupled into the transmission line S. The coupling structures 21 are in FIG. 2 marked by corresponding dashed borders belonging respectively to the individual transmission lines.

The coupling devices 21 each have a housing (in Fig. 1 see reference numeral 11), are attached to the two RF terminal structures 1, 2, in the form of coaxial connections for coupling to the outside of the coupling devices 21 line sections 22, 23, 24 .... According to the comments to FIG. 1 the inner conductors of the coaxial terminals 1, 2 are electrically conductively connected within the respective housing by means of a line structure, so that the line structure 5, in cooperation with the line sections 22, 23, 24, ... in principle a part of the antenna line or the common transmission line S. represents. The dimensions of the line structure and the housing are each chosen so that a possible lossless transmission of transmitted to the transmission line S RF signals is made possible.

For capacitive coupling of the individual RF signals HF1, HF2,..., HFn along the respective line structure and thus along the entire transmission line S, each coupling device 21 has a tube capacitor structure which, in conjunction with the exemplary embodiment in FIG FIG. 1 is explained.

While the capacitive coupling of the RF signals to the transmission line S remains the same through the tube capacitor structure, it is possible to adapt the capacitive coupling of the coupling device 21 individually to the coupling ratios of the filters B1,..., Bn. Typically, the bandpass filters B1, B2,..., Bn are each designed as a cup-circle filter consisting of one or more well circuits coupled to one another in terms of HF. The HF-moderate coupling of the coupling device 21 to the respective band-pass filter B1, B2,..., Bn can be seen via the insertion depth of the respective second section 8 of the coupling structure 12 figure 1 be set in an interior of a cup circle of the bandpass filter by the immersion depth of the second portion 8 by longitudinal displacement of the entire coupling structure 12 by the means 15 is variable.

LIST OF REFERENCE NUMBERS

• 1, 2 Coaxial connection structures
• 3, 4 inner conductor of the connection structures
• 5 line structure
• 6 First section of the coupling structure
• 7 insulator
• 8 Second section of the coupling structure
• 9 opening in the second housing wall
• 10 First housing wall
• 11 housing
• 12 coupling structure consisting of 6 and 8
• 13 hole, opening
• 14 rod longitudinal axis
• 15 funds
• 18 Second housing wall
• 19 connection structure
• 20 RF module
• 21 Apparatus for coupling an RF signal along a signal path
• 22, 23, 24 pipe sections
• HF1, HF2 RF signals
• S1, S2 transmission channels
• B bandpass filter
• λ ₁ , λ ₂ wavelengths of the RF signals HF1, HF2
• S transmission line
• K short circuit
• O1, O2 coupling points
• SP signal path
• AT antenna output

Claims (14)

1. A device for coupling an HF signal along a signal path (SP), which extends between a first and a second coaxial HF connection structure, wherein the two coaxial HF connection structures (1, 2) each comprise an internal conductor (3, 4) electrically connected to each other via a line structure (5) with the line structure (5) being capacitively coupled to an electrically conducting coupling structure (12), via which the HF signal can be coupled along the signal path (SP),
   wherein the line structure (5) consistently connects the two coaxial HF connection structures (1, 2) to each other,
   a bore or opening (13) oriented essentially transversely to the longitudinal extension of the line structure (5) is drilled along the line structure (5), through which a first portion (6) of the coupling structure (12) protrudes,
   the first portion (6) of the coupling structure (12) and the line structure (5) are spaced apart from each other by means of an insulator (7),
   the HF signal can be capacitively coupled between the first portion (6) of the coupling structure (12) and the line structure (5),
   characterised in that the coupling capacity between the coupling structure (12) and the line structure (5) is constant.
2. The device according to claim 1,
   characterised in that the line structure (5) is formed in one piece.
3. The device according to claim 1 or 2,
   characterised in that the first portion (6) of the coupling structure (12) is rod-shaped and the insulator (7) is sleeve-shaped and in that the sleeve-shaped insulator (7) radially surrounds, at least partially, the rod-shaped first portion (6) of the coupling structure (12).
4. The device according to claim 3,
   characterised in that the first portion (6) of the coupling structure, the insulator (7) and the line structure (5) form a pipe capacitor in the area of the bore or opening (13).
5. The device according to claim 3 or 4,
   characterised in that the rod-shaped first portion (6) of the coupling structure (12) has a rod longitudinal axis (14), which at the same time is a rotational axis, about which the coupling structure (12) is mounted so as to be rotatable and/or longitudinally movable.
6. The device according to one of claims 1 to 5,
   characterised in that the first and the second coaxial HF connection structures (1, 2) are attached to a housing (11), in the housing interior of which is housed the line structure (5) which connects the internal conductors (3, 4) of the HF connection structures (1, 2) with each other.
7. The device according to claim 6,
   characterised in that at least the first portion (6) of the coupling structure (12) is attached inside the housing (11) and indirectly or directly engages with a means (15), which protrudes through the housing (11) to the outside through a first housing wall (10), and in that the coupling structure (12) is rotatably and/or longitudinally movable with the aid of the means (15).
8. The device according to claim 7,
   characterised in that the housing (11), in a second housing wall (18) opposite the first housing wall (10), has an opening (9), through which protrudes a second portion (8) of the coupling structure (12) connected HF-wise to the first portion (6), and
   in that a connection structure (19) is attached to the second housing wall (18), to which an HF assembly (20) can be attached, from which an HF signal can be coupled via the second portion (8) into the coupling structure (12) and via the first portion (6) of the coupling structure (12) into the line structure (5).
9. The device according to claim 8,
   characterised in that the second portion (8) of the coupling structure (12) comprises a plate-shaped or disc-shaped contour.
10. A device for coupling at least two HF signals (HF1, HF2) into a common transmission line (S), wherein the at least two HF signals (HF1, HF2) each have a transmission channel (S1, S2) assigned to them, along each of which at least one bandpass filter (B) is arranged which couples the respective transmission line (S1, S2) to the signal path (S),
    characterised in that a device according to one of claims 1 to 9 is provided for respectively coupling the at least two HF signals (HF1, HF2) into the common transmission line (S) such that the respective coupling structure (12) couples capacitively to the bandpass filter (B) of the respective transmission channel (S1, S2), and
    in that an HF connection structure (1, 2) of both devices are respectively coupled HF-wise to each other, and that the line structures (5) of both devices as well as the HF-wise coupling of both HF connection structures (2, 1) form the common transmission line (S).
11. The device according to claim 10,
    characterised in that the bandpass filter is a cavity resonator filter made up of one or more cavity resonators coupled HF-wise together.
12. The device according to claim 11,
    characterised in that an HF-wise coupling of the coupling structure (12) to the bandpass filter is adjustable via an immersion depth of the second portion (8) of the coupling structure (12) into an interior of the cavity resonator of the bandpass filter.
13. The device according to claim 12,
    characterised in that the immersion depth of the second portion (8) is changeable by the means (15) moving the entire coupling structure (12) longitudinally.
14. The device according to one of claims 10 to 13,
    characterised in that the at least two HF signals (HF1, HF2) can each be assigned a wavelength (λ₁, λ₂),
    in that the transmission line (S) is short-circuited HF-wise at one end,
    in that the at least two HF signals (HF1, HF2) can each be coupled at different coupling-in points (O1, O2) along the transmission line (S) and
    in that the coupling-in points (O1, O2) are each at a distance from the short-circuited end of the transmission line, which corresponds to an odd-numbered multiple of λ₁/4 or λ₂/4.

Images