EP2363912A1 - Diplexer for a reflector antenna - Google Patents

Abstract

The diplexer (1) has a hollow conductor arrangement (5) for forming two coaxial hollow conductor gates. The hollow conductor arrangement comprises an annular hollow conductor (7) in which a signal is processed during operation of the diplexer. An inner conductor (8) is arranged at the interior of the hollow conductor. Another signal with reduced frequency than the former signal is processed in another circular hollow conductor (9), where the latter hollow conductor surrounds the former hollow conductor. The two conductors are ended with same or different heights. An independent claim is also included for a method for processing a diplexer.

Description

The invention relates to a diplexer for a reflector antenna for transmitting microwave signals. The invention further relates to a method for processing a received signal fed into a diplexer.

Large reflector antennas require a very precise alignment with respect to a transmitter and / or receiver, generally a remote site due to their very narrow radiation characteristics. For orientation, a beacon signal emitted by the remote station is used. For evaluating the beacon signal by the reflector antenna or an evaluation unit coupled to the reflector antenna, a directional diagram with a zero point in the main beam direction is required. In the case of a deviation of the beacon signal from the main beam direction, an additional signal is received, which can be used to correct the direction deviation. The transmission, separation and evaluation of the beacon signal is in addition to the transmission of the actual communication signal. The beacon signal must not influence the communication signal.

A reflector antenna for transmitting microwave signals typically includes a diplexer having a common signal waveguide for transmitting a transmit signal and a receive signal. The common signal waveguide includes first and second ends. Connected to the first end of the common signal waveguide is a horn, via which a decoupling of the transmission signal and an injection of the transmission signal into the common signal waveguide takes place. With the common signal waveguide is usually coupled to a plurality of waveguide gates for feeding the transmit signal into the diplexer and for coupling the received signal from the diplexer in a receiving network. The waveguide gates are, for example, symmetrically distributed on the outside of the common signal waveguide and in each case communicatively connected to the common signal waveguide.

In particular, the purpose of the diplexer is to process a mode mixture of modes of the received signal in such a way that it is possible to distinguish between the actual communication signal and correction data for the communication signal. At the same time, the diplexer must correctly transmit a transmission signal fed into the plurality of signal waveguides for coupling out through the horn. The thereby existing conflict of objectives, both correctly split the received signal in terms of its communication signal and the correction information and decouple the transmission signal with the desired polarization of the reflector antenna, is not always solved satisfactorily.

From the US 3,922,621 For example, a coaxial diplexer for a reflector antenna for transmitting microwave signals is known. The diplexer comprises a first circular waveguide in which a first signal can propagate. It further comprises a second, circular waveguide, in which a second signal can propagate at a lower frequency than the first signal, wherein the second waveguide surrounds the first waveguide. A portion of the second waveguide is formed as a groove waveguide having a number of itself along a circumferentially annularly extending grooves. As a result, an effective decoupling of transmit and receive signal is effected. However, in the diplexer the US 3,922,621 no propagation of a tracking signal is possible with which a correction of the directional deviation of the reflector antenna can be determined.

From the unpublished German patent application DE 10 2008 004 895.8 is a signal branch with a common signal waveguide for transmitting a transmitted and a received signal known. There is provided a plurality of transmitting signal waveguides for feeding the transmission signal, wherein the transmission signal waveguides are arranged symmetrically distributed on the outside of the common signal waveguide and are communicatively connected to the common signal waveguide. Likewise, a plurality of receiving signal waveguides for transmitting the received signal is provided, wherein the Reception signal waveguide symmetrically connected to the common signal conductor and also communicatively connected to the common signal waveguide. In order to detect a tracking signal, the arrangement of filters in the receiving signal waveguides is required.

From the US 6,937,202 B2 It is known to separate modes by reducing the diameter of the horn below a critical diameter. This is called a virtual short circuit. A common decoupling of received signal (from the perspective of a satellite) and tracking signal with simultaneous separation of the transmission signal is not possible. The side arms require filters for this purpose.

The US 2003/0222733 A1 discloses the separation of modes by reducing the diameter of the horn below the critical diameter by means of a virtual short circuit. A common decoupling of received signal (from the perspective of the satellite) and tracking signal with simultaneous separation of the transmission signal is not possible. The disclosure relates to ground station applications where due to reverse assignment of transmit and receive bands the indicated feed system structure can be used. Filters are mandatory in the side arms.

It is therefore an object of the present invention to provide a diplexer for a reflector antenna for transmitting microwave signals, which allows improved correction of the directional deviation of the reflector antenna. It is a further object of the present invention to specify a method for processing a received signal fed into a diplexer, which enables improved accuracy for correcting the directional deviation.

These objects are achieved by the features of the independent claims. Advantageous embodiments of the invention will become apparent from the dependent claims.

The invention provides a diplexer for a reflector antenna for transmitting microwave signals. It comprises a common, circular signal waveguide for transmitting a transmission signal and a reception signal comprising a first end and a second end, wherein at the first end a common gate is formed. The diplexer further comprises a waveguide arrangement, which is arranged in the region of a second end of the signal waveguide coaxial with the signal waveguide. Further, a cylindrical coupling portion is provided, which is arranged between the first and the second end of the signal waveguide and connects the waveguide arrangement with the common signal waveguide. The invention is characterized in that the waveguide arrangement for forming a first and second coaxial waveguide gate comprises a first, circular and a second circular waveguide. In the first, circular waveguide, a first signal can propagate during operation of the diplexer, wherein an inner conductor is arranged in the interior of the first waveguide. Through the first, circular waveguide, a received signal (also referred to as receiving band hereinafter) is passed. In a second circular waveguide, during operation of the diplexer, a second signal (a transmission signal or transmission band) may propagate at a lower frequency than the first signal, wherein the second waveguide surrounds the first waveguide.

The invention further provides a method for processing a signal fed into a diplexer according to the invention. In the method according to the invention, a TE11 mode is fed into the common port. A TM11 mode is excited in the signal waveguide and superimposed with the TE11 mode such that the entire energy of the second signal (in the transmission band) by a constructive superposition of outer field components and a destructive superposition of inner field components in the second, outer waveguide flows and that the entire energy of the first signal (in the receiving band) flows through a constructive superposition of internal field components and a destructive superposition of external field components in the first, inner waveguide. The first signal (in the receiving band) is transferred at feeding the TM01 mode at the common gate in the TEM mode of the first waveguide. From the TE11 mode and the TM01 mode of the first signal (in the receiving band), an information for aligning the reflector antenna is determined by processing the modes.

The invention thus proposes to separate the transmit and receive signal and at the same time to perform a transformation of the mode TM01 in the TEM mode in the receive band, so that a tracking signal for antenna alignment is available in the receive band in addition to the communication signal. This is made possible by the use of an inner conductor, which is arranged in the interior of the first waveguide.

An advantage of this procedure is that the sum and difference signals required for the tracking are coupled out under the same conditions, in particular at the same temperature. As a result, phase errors are avoided by different temperatures in the RF paths.

Another advantage is that the tracking signal is decoupled only after the transmit and receive signals have been separated. As a result, disturbances of the transmission signal are avoided by a Trackingmodenkoppler.

Compared to the solutions known from the prior art, no filters in the side arms are required to separate the transmission signal. Thus, the feed system is much less sensitive to manufacturing uncertainties.

Conveniently, the diplexer according to the invention is a coaxial diplexer. This is due to the coaxial arrangement of the first, circular waveguide, which is surrounded by the second circular waveguide.

It is also expedient if the inner conductor is formed pin-shaped. In particular, the first waveguide and the inner conductor end at the same or different height.

A further embodiment provides that the coupling portion is formed as a first groove waveguide, which has to the interior of the signal waveguide through a number of annularly extending grooves along an inner circumference. The first groove waveguide adjoins the second end of the signal waveguide.

It is further contemplated that the second waveguide is at least partially formed as a second groove waveguide, the inside of the signal waveguide towards a number of along an inner circumference annularly extending grooves. The second groove waveguide preferably adjoins the coupling section or the second end of the signal waveguide.

The grooves of the first and / or second groove waveguide are each arranged equidistant from each other. In a specific embodiment it can be provided that the distance between respective grooves of the first groove waveguide is different than the distance between respective grooves of the second groove waveguide.

The diplexer according to the invention is further distinguished by the fact that the second waveguide port (in the transmission band) is coupled with a turnstile branching and two 180 ° hybrid couplers or with two coaxial sidearm orthomode transformers to produce dual linearly polarized signals. Alternatively, the second waveguide port (in the transmit band) is coupled to one polarizer, one turnstile branch and two 180 ° hybrid couplers, or to one turnstile branch, two 180 ° hybrid couplers, and one 90 ° hybrid coupler for dual circular polarization generation.

In another embodiment, the first waveguide port (in the receive band) is for generating linear polarization with a turnstile branch and three 180 ° hybrid couplers coupled. Alternatively, the first waveguide port (in the receive band) is coupled to a turnstile branch, three 180 ° hybrid couplers, and a 90 ° hybrid coupler to produce circular polarization.

• Fig. 1 eine perspektivische Darstellung eines erfindungsgemäßen Diplexers,
• Fig. 2 eine perspektivische, geschnittene Darstellung eines erfindungsgemäßen Diplexers,
• Fig. 3 einen teilweisen Ausschnitt eines erfindungsgemäßen und teilweise geschnittenen Diplexers,
• Fig. 4 ein Blockschaltbild für die Anwendung des erfindungsgemäßen Diplexers gemäß einer ersten Ausführungsvariante,
• Fig. 5 ein Blockschaltbild für die Anwendung des erfindungsgemäßen Diplexers gemäß einer zweiten Ausführungsvariante, und
• Fig. 6 ein Blockschaltbild für die Anwendung des erfindungsgemäßen Diplexers gemäß einer dritten Ausführungsvariante.

The invention will be explained in more detail with reference to the figures. Show it:

• Fig. 1 a perspective view of a diplexer according to the invention,
• Fig. 2 a perspective, sectional view of a diplexer according to the invention,
• Fig. 3 a partial section of a partially sectioned diplexer according to the invention,
• Fig. 4 a block diagram for the application of the diplexer according to the invention according to a first embodiment,
• Fig. 5 a block diagram for the application of the diplexer according to the invention according to a second embodiment, and
• Fig. 6 a block diagram for the application of the diplexer according to the invention according to a third embodiment.

The FIGS. 1 to 3 show a coaxial diplexer 1 according to the invention for a reflector antenna for transmitting microwave signals. The diplexer 1 comprises a common, circular signal waveguide 2 for transmitting a transmission signal and a reception signal. The signal waveguide 2 comprises a first end 3 and a second end 4. At the first end 3, a common gate 20 is formed. A cylindrical coupling section 6 is arranged between the first and the second end 3, 4 of the signal waveguide 2, the cylindrical coupling section 6 adjoining the second end 4. The cylindrical one Coupling section 6 is formed as a first groove waveguide 10. This has to the interior of the signal waveguide 2 towards a number of along an inner circumference annularly extending grooves 11. The grooves 11 are arranged equidistant from each other. Inside the common signal waveguide 2 and adjacent to the second end 4 of the signal waveguide 2, a waveguide assembly 5 connects. This is arranged coaxially with the signal waveguide 2.

To form a first and a second coaxial waveguide gate 21, 22, the waveguide assembly 5 comprises a first, circular waveguide 7, in which a first signal in the receiving band can propagate during operation of the diplexer, wherein a pin-shaped inner conductor 8 is arranged in the interior of the first waveguide 7 is. The first waveguide 7 and the inner conductor 8 terminate in the embodiment at an equal height, but this is not mandatory. A second, circular waveguide 9, which adjoins the second end of the signal waveguide 2, surrounds the first waveguide 7. In the second waveguide 9, a second signal may propagate in the transmission band at a lower frequency than the first signal in the reception band during operation of the diplexer ,

The second waveguide 9 is formed at least in sections as a second groove waveguide 12. The second groove waveguide directly adjoins the second end of the signal waveguide 2 or the coupling section 6 or first groove waveguide 10. The second groove waveguide 12 has a number of grooves 13 extending annularly along an inner circumference towards the interior of the signal waveguide. The grooves of the second groove waveguide 12 are arranged only by way of example equidistant from each other. The distance between the grooves 13 of the second groove waveguide 12 is greater than the distance between the grooves 11 of the first groove waveguide 10th

At the end facing away from the common signal waveguide end of the first waveguide 7 and the second waveguide 9 each four symmetrically arranged transmitting waveguide 15 and receive waveguide 14 are provided. These each have a rectangular cross-section and are arranged orthogonal with respect to a longitudinal or symmetry axis of the coaxial diplexer 1.

The common port 20, which is connected to a horn, is powered by the TE11 mode. By suitable dimensioning of the grooves 11, the TM11 mode is excited within the diplexer. It overlaps with the TE11 mode such that in the transmit band (i.e., a lower frequency band), all of the energy flows into the outer, coaxial waveguide (i.e., the second waveguide 9) through constructive superposition of the outer and destructive superposition of the inner field components. In the receiving band (upper frequency band), the inner field components overlap constructively and the outer field components destructively. As a result, all the energy flows into the inner coaxial waveguide, i. the first waveguide 7, in the interior of which the inner conductor 8 is arranged.

Through the inner conductor the energy in the TEM mode of the inner coaxial waveguide, i. of the first waveguide 7, transferred. From the TE11 mode and the TM01 mode in the receiving band, the necessary information for aligning the antenna can be obtained by signal processing.

With the diplexer according to the invention, it is possible, by means of a suitable network of hybrid couplers, a turnstile branch, to split the received mixture of modes into individual modes and, if necessary, to recombine them. In this way, the received communication signal can be separated from the tracking modes and a tracking signal can be generated which contains the information about the amount and direction of the registration deviation. This allows a direct correction of the antenna alignment.

For the generation of dual linearly polarized signals, the coaxial diplexer in the transmit band is supplemented by a turnstile branching and two 180 ° hybrid couplers or by two coaxial sidearm orthomode transducers (OMTs).

In dual circular polarization, a polarizer, a turnstile junction and two 180 ° hybrid couplers or a turnstile junction, two 180 ° hybrid couplers, and a 90 ° hybrid coupler may be provided in the transmit band.

In the receive band, a turnstile branch and three 180 ° hybrid couplers are used in linear polarization. With circular polarization, an additional 90 ° hybrid coupler is added.

These embodiments are described below in the FIGS. 4 to 6 shown.

The FIGS. 4 to 6 show various block diagrams for the application of the diplexer according to the invention. The reference numeral 30 in each case denotes a horn which is coupled to the coaxial diplexer 1 according to the invention. With Tx is a transmission path, with Rx a reception path is indicated.

In the transmission path of the Fig. 4 a coaxial polarizer 41 is connected to the diplexer 1. Further, a coaxial orthomode transformer 42 is connected to the coaxial polarizer 41. The co-orthomode transmitter receives payload data Tx LHCP and Tx RHCP to be transmitted. In the reception path Rx, a turnstile branch 43 is connected to the coaxial diplexer 1. This is coupled to two 180 ° hybrid couplers 44, 46. A respective difference signal Δ is supplied to a 90 ° hybrid coupler 45 to which received payload data Rx LHCP and Rx RHCP are provided. The sum signals (Σ) of the 180 ° hybrid coupler are fed to another 180 ° hybrid coupler 47, which forms a sum and a difference signal (Σ, Δ). The sum signal (Σ) represents the tracking signal (ΔTP) necessary for correcting the antenna alignment.

In the transmission path of the Fig. 5 only a coaxial orthomode transformer 42 is coupled to the diplexer 1. This receives user data to be sent Tx HP and Tx VP. In the reception path Rx, the turnstile branch 43 is coupled to the diplexer 1. On the output side, the turnstile branch 43 is coupled to two 180 ° hybrid couplers 44, 46. These each form a sum and difference signal (Σ, Δ). From the difference signals Δ received user data Rx HP and Rx VP can be obtained. The sum signals (Σ) are fed to a further 180 ° hybrid coupler 47, the tracking information (ΔTP) being obtained from a sum signal (Σ) formed by the same.

In the embodiment of Fig. 6 is the reception path Rx according to the in Fig. 4 shown receiving path formed. In the transmission path Tx, a coaxial turnstile branch 50 is likewise provided, which is connected to the diplexer 1. Turnstile junction 50 is coupled to two 180 ° hybrid couplers 51, 52. A 90 ° hybrid coupler 53, to which payload data Tx LHCP and Tx RHCP to be transmitted are supplied, is coupled to differential inputs (Δ) of the 180 ° hybrid couplers 51, 52.

The receiving network of the illustrated embodiments simultaneously serves to decouple the TEM mode with the tracking information. The closely adjacent coupling of the TE11 mode in the receive band and the TEM mode, in particular the similar thermal conditions, mean that the automatic antenna alignment is very accurate and temperature-stable on the basis of the tracking information.

LIST OF REFERENCE NUMBERS

1

diplexer

2

common signal waveguide

3

first end of the common signal waveguide

4

second end of the common signal waveguide

5

Waveguide arrangement

6

coupling section

7

first waveguide

8th

inner conductor

9

second waveguide

10

first corrugated waveguide

11

grooves

12

second groove waveguide

13

grooves

14

Receiving waveguide

15

Transmission waveguide

20

common gate

21

first waveguide gate

22

second waveguide gate

30

horn

41

coaxial polarizer

42

Coaxial orthomode transformer

43

turnstile

44

180 ° hybrid coupler

45

90 ° hybrid coupler

46

180 ° hybrid coupler

47

180 ° hybrid coupler

50

Turnstile branch

51

180 ° hybrid coupler

52

90 ° hybrid coupler

53

180 ° hybrid coupler

Tx

transmission path

Rx

receive path

Tx LHCP

User data of a transmission signal

Tx RHCP

User data of a transmission signal

Rx LHCP

User data of a received signal

Rx RHCP

User data of a received signal

Tx HP

User data of a transmission signal

Tx VP

User data of a transmission signal

Rx HP

User data of a received signal

Rx VP

User data of a received signal

Claims (14)

Diplexer for a reflector antenna for transmitting microwave signals, comprising: - A common, circular signal waveguide (2) for transmitting a transmission signal and a reception signal comprising a first end (3) and a second end (4), wherein at the first end (3) has a common gate is formed; a waveguide arrangement (5) which is arranged coaxially with the signal waveguide (2) in the region of the second end of the signal waveguide (2) and connects the Holleiteranordnung with the common signal waveguide, a cylindrical coupling section (6) which is arranged between the first and the second end of the signal waveguide (2), characterized in that the waveguide arrangement (5) for forming a first and a second coaxial waveguide gate (21, 22) comprises: - A first, circular waveguide (7), in which during operation of the diplexer (1) can propagate a first signal, wherein in the interior of the first waveguide, an inner conductor (8) is arranged, and - A second, circular waveguide (9), in which during operation of the diplexer (1) a second signal with a lower frequency than the first signal can propagate, wherein the second waveguide (9) surrounds the first waveguide (7). Diplexer according to claim 1, characterized in that the inner conductor is pin-shaped. Diplexer according to claim 1 or 2, characterized in that the first waveguide (7) and the inner conductor (8) terminate at a same or different height. Diplexer according to one of the preceding claims, characterized in that the coupling portion (6) is formed as a first groove waveguide (10) to the interior of the signal waveguide (2) towards a number of along an inner circumference annularly extending grooves (11). Diplexer according to claim 4, characterized in that the first groove waveguide (10) adjoins the second end of the signal waveguide (2). Diplexer according to one of the preceding claims, characterized in that the second waveguide (9) is formed at least in sections as a second groove waveguide (12) leading to the interior of the signal waveguide (2) a number of grooves (13) extending annularly along an inner circumference. having. Diplexer according to Claim 6, characterized in that the second groove waveguide (12) adjoins the coupling section (6) or the second end of the signal waveguide (2). Diplexer according to claim 6 or 7, characterized in that the grooves of the first and / or second groove waveguide (10, 12) are each arranged equidistant from each other. Diplexer according to one of claims 1 to 8, characterized in that the second waveguide gate (22) (in the transmission band) for generating dual linearly polarized signals - with a turnstile junction and two 180 ° hybrid couplers, or - Coupled with two coaxial side arm orthomode transformers. Diplexer according to one of claims 1 to 8, characterized in that the second waveguide gate (22) (in the transmission band) for generating dual circular polarization with one polarizer, one turnstile branch and two 180 ° hybrid couplers, or - with a turnstile branching, two 180 ° hybrid couplers and a 90 ° hybrid coupler is coupled. Diplexer according to one of Claims 1 to 10, characterized in that the first waveguide port (21) (in the receiving band) is coupled to a turnstile branch and three 180 ° hybrid couplers to produce linear polarization. Diplexer according to one of claims 1 to 10, characterized in that the first waveguide gate (21) (receiving band) is coupled to generate circular polarization with a turnstile branch, three 180 ° hybrid couplers and a 90 ° hybrid coupler. Diplexer according to one of the preceding claims, characterized in that it is a coaxial diplexer. Method for processing a signal fed into a diplexer (1) designed according to one of the preceding claims, in which - in the common gate a TE11-mode is fed, - A TM11 mode in the signal waveguide (2) is excited and superimposed with the TE11 mode such that the entire energy of the second signal flows through a constructive superposition of external field components and a destructive superposition of internal field components in the second waveguide and that the entire energy of the first signal through a constructive overlay of internal field components and a destructive superposition of external field components into the first inner coaxial waveguide, the first signal is transferred to the common gate in the TEM mode of the first waveguide when the TM01 mode is fed in, - Information for aligning the reflector antenna is determined from the TE11 mode and the TM01 mode of the first signal by processing the modes.

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