WO1998008270A1

WO1998008270A1 - Multifocus reflector antenna

Info

Publication number: WO1998008270A1
Application number: PCT/EP1997/004467
Authority: WO
Inventors: Lutz Rothe; Klaus Eidner
Original assignee: Pates Technology Patentverwertungsgesellschaft Für Satelliten- Und Moderne Informationstechnologien Mbh
Priority date: 1996-08-18
Filing date: 1997-08-15
Publication date: 1998-02-26
Also published as: EP0919072A1; DE19633147A1; DE59709162D1; EP0919072B1; ATE231292T1; TW389004B; ES2191856T3

Abstract

A reflector antenna is disclosed for simultaneously receiving the radiation fields of n≥2 satellites positioned on orbit at azimuthally offset positions with respect to one another. The reflector antenna has a reflector (1), in particular a parabolic reflector, and an n number of radiation exciters (3; 3.1; 3.2) arranged in a line in the focal area of the reflector (1) to receive polarised radiation. The radiation exciters (3; 3.1; 3.2) are arranged in the focal area at fixed geometrical distances A to each other, so that each radiation exciter (3; 3.1; 3.2) is associated with one radiation source of a satellite, the distance A between the radiation exciters (3; 3.1; 3.2) corresponding to the in particular azimuthally offset positioning of the radiation sources of the satellites to be received. A planar excitation network (8) decouples two orthogonal and linearly polarised wave fields from each radiation exciter (3; 3.1; 3.2). A coupling network (9) switches the decoupled wave fields to the input of respective noise-adapted input signal amplifiers (16.1; 16.2; 16.3; 16.4). The output signal of an input signal amplifier (16) can be selectively supplied to a low-noise converter (21) by means of one or several switches or by means of the input signal amplifiers (16; 17), which in this case can be switched between an amplifying mode and a locking mode.

Description

Multifocus reflector nteππe

The invention relates to a reflector antenna for the simultaneous reception of the radiation fields from n__2 satellites positioned azimuthally offset from one another in orbit, the reflector antenna having a parabolic reflector, in particular, and n arranged on a line in the focal region of the reflector for receiving polarized radiation, the radiation exciter are arranged in the focal region at fixed geometric distances from one another, such that one radiation exciter each

Radiation source is assigned to a satellite and the distance of the radiation exciter corresponds to the particularly azimuthal offset of the radiation sources to be received from the satellites.

The antenna solutions currently available for multiple reception of satellite sources are based on the mutually angularly offset arrangement of a plurality of excitation systems in the focal area of a reflector or on the horizontal movement of an excitation system within the focal area of the reflector. In both cases, the excitation systems consist of passive hollow-wave radiators, each of which is coupled to a converter module with a low-noise converter. In the first case, the known solution therefore consists in multiplying the entire excitation system, consisting of Radiator and conversion components, on the one hand multiplying the corresponding cost items and, on the other hand, the reaction cross-section of conductive disturbances in the burning area of the reflector is increased. Furthermore, the recipient-related control-related effort increases with the number of excitation systems to be controlled. The second case requires the necessary actuators in the form of a motor-mechanical movement apparatus and an associated control for the known horizontal linear movement of the excitation system. The solutions known on this basis also take into account the changes or rotations of the polarization plane which are effective as a function of the particular constellation between the target orbit position and the location of the receiver system, and thus cause a reduction in the system quality of the antenna arrangement under the influence of the respective polarization losses. In the case of the movable excitation systems, the alignment of the reflector antenna is also difficult to perform by inexperienced laymen, since it requires a precise determination of the positions to be approached by the excitation system.

The object of the invention is to provide a multifocus reflector antenna, the technical structure of which is simplified compared to the known systems of the prior art, i.e. has fewer components and as a result the functional reliability of the antenna is increased and the production costs are reduced.

This object is achieved according to the invention in that a planar excitation network decouples two mutually orthogonally and linearly polarized wave fields from each radiation exciter, and in that the decoupled wave fields are each connected to the input of noise-matched associated input signal amplifiers by means of a coupling network, and that optionally by means of one or more switches or the input signal amplifier, which in this case can be switched to amplification and blocking mode, the output signal of an input amplifier can be fed into a low-noise converter. By using only a standard low-noise

There is a converter for all radiation exciters

Reflector antenna advantageous from only a few components, which in comparison to the known multifocus antennas

Antenna can be produced more cost-effectively because low-noise converters, due to their complicated structure, cause a considerable part of the manufacturing costs of the reflector antenna. Weight is also saved by using only a low-noise converter in the reflector antenna according to the invention and the outer dimensions of the reflector antenna can be made smaller. It will also be advantageous

Operational safety increased, since only one instead of the otherwise several

Converter is needed.

In a preferred embodiment, the low-noise converter has n inputs, a changeover switch, a mixer and at least one “local oscillator” (LO) for generating a comparison frequency, the output signals of the input amplifiers of a radiation exciter being input to a low-noise converter The switch consists of two paths, each of which is formed by extremely low-noise, in particular HEMT (high electron mobility transistors) transistors, the transistors either in the amplifier or blocking mode The inputs of the transistors form the inputs of the low-noise converter. The outputs are coupled to a common signal path leading to the mixer. The transistor operating in amplifier mode forms the active path to the mixer for the decoupled wave field of the radiation exciter. the one with the respective input of the low-noise converter is connected.

If you choose n = 2, a commercially available low-noise converter can be used. It should be noted that commercially available low-noise converters only have two inputs, each input being intended for a polarized wave field of an excitation system that is coupled out of the hollow-wave radiator. Using the switch integrated in the low-noise converter only one input is switched to the downstream mixer. In the reflector antenna according to the invention, however, this changeover switch is not used to switch back and forth between two differently polarized wave fields, but rather serves to switch back and forth between the two excitation systems. By means of an upstream amplifier switching stage, the vertically or horizontally polarized, pre-amplified outcoupled wave field of the excitation system assigned to the input is applied to one input of the low-noise converter. Each radiation exciter of the reflector antenna advantageously has a hollow-wave radiator with a defined boundary and geometry, which is excited by means of a hollow-waveguide segment. The waveguide segment is designed in such a way that the n hollow wave radiators are fixed at their spacing from one another, the spacing being chosen in accordance with the azimuthally offset satellite systems. By means of the spacing of the hollow-wave radiators from one another specified in the exemplary embodiment, the reflector antenna according to the invention can advantageously be used almost throughout Europe.

By means of a planar excitation network consisting of two microstrip conductors of defined geometry and boundary arranged spatially orthogonally to one another, the geometry and boundary determining the wave resistance of the microstrip conductor and the optimal adaptation to the downstream components, two excitation systems are coupled out orthogonally and linearly polarized with each excitation system and led to the assigned inputs of the low-noise converter. The excitation network consists of a combination of microstrip and triplate waveguides.

The reflector antenna has a control unit for controlling the input signal amplifiers, the polarization-selecting control circuits downstream of the input amplifiers, the changeover switch, the mixer and the “local oscillator” (LO) The control unit controls the reference frequency of the mixer by controlling the “local oscillators” and the signal path by means of the switch of the low-noise converter, as well as the input amplifiers and the control circuits of the excitation systems.

An embodiment of the reflector antenna according to the invention is explained in more detail below with reference to figures.

Show it:

Figure 1: A schematic diagram of the parabolic reflector;

Figure la: a plan view of the reflector antenna with hollow-wave radiators arranged in the focal area;

FIG. 2: a cross-sectional view and a top view of a hollow waveguide radiator;

FIG. 3: a cross-sectional view and a top view of an excitation hollow waveguide;

FIG. 4: a top view of an excitation network;

Figure 4a: a further embodiment of the excitation network;

Figure 5: Block diagram of the reflector with downstream electronics incl. Low-noise converter and satellite receiver;

Figure 6: Top view of the component holder;

Figure 7: Geographical dependence of the gain value level of the antenna arrangement for the case of a selected one b

Distance of the axes of the hollow wave radiators from A = 73mm;

characters

8 and 8a: cross-sectional representation of the entire reflector antenna with respect to the mechanical coupling of the components of the

Representations 2 to 4.

Figure 1 is a schematic diagram of the parabolic reflector (1). The satellite signals impinging on the reflector 1 from the direction of incidence are focused by the reflector 1 in the focal area. As can be seen from FIG. 1 a, the emitter module 2 is arranged fixedly or rigidly to the reflector in the focal area. The radiator module 2 carries the radiation exciters 3, consisting of the component receptacle 18, each of two hollow-wave radiators 8.1 and 8.2 according to FIG. 2, the hollow-waveguide segment 13 according to FIG. 3, the planar excitation network 9 and coupling network 15 according to FIG. 4. The hollow-wave radiators 8.1 and 8.2, the hollow waveguide segment 13 and the planar excitation network 9 and coupling network 15 are arranged with respect to one another in accordance with FIG. 8.

The dimensions of the axis of the reflector 1 are for the frequency range to be received from 10.70 to 12.75 GHz for the major axis Dv = 81cm and for the minor axis Dh = 72cm.

According to FIG. 1 a, a line of n = 2 is of the same type in the focal region of the named reflector 1

Radiation exciters 3 are arranged by positioning the radiation exciter 3.1 in the focal region of the reflector 1 in offset mode and the radiation exciter 3.2 at a horizontal distance al from the radiation exciter 3.1, the distance al = 64mm in the event that the antenna arrangement within the geographical limits is 50 degrees north Latitude and 62 degrees north latitude and 10 degrees west Longitude and 30 degrees east longitude is used, as well as al = 73mm in the event that the antenna arrangement is used within the geographical limits of 45 degrees north latitude and 55 degrees north latitude or 10 degrees west longitude and 30 degrees east longitude. The radiation exciters 3 are each formed from a passive radiator component 6 and an active signal path 7. The passive radiator components 6 are configured as hollow waveguide radiators 8 with the geometric dimensions and the border according to FIG. 2. Aluminum / aluminum die casting or brass / brass die casting or zinc / zinc die casting are preferably used as materials. The hollow waveguide radiator 8 is designed as a rotationally symmetrical groove arrangement such that a first groove segment with the diameter i8 and the depth sl is coupled to a second groove segment with the diameter iβ and the depth s2-s6 by the two groove segments overlapping with the dimension sl-s6 . The second groove segment is overlapped with a third groove segment of depth s3-s7 and diameter i4, the overlap height being s2-s7. The third grooved segment includes a hollow waveguide segment with the diameter il and the length s4-s8, the overlap height between the third grooved segment and the hollow waveguide segment being s3-s8. The groove width of the third groove segment is (i4-i3) / 2 and, measured at a height s9, extends from the radiator entry surface to the value (i4-i2) / 2. The hollow waveguide segment with the diameter il is extended axially by means of a hollow waveguide segment with the geometric length s5-s4 and with the diameter 2rl. The first and second groove segments are overlapped at a radial distance (i7-i6) / 2 from each other; the second and third groove segments are overlapped at a radial distance (i5-i4) / 2 from each other. The third groove segment and the subsequent hollow waveguide segment are overlapped at a radial distance (i3-i2) / 2 from each other. The shaft coupling o takes place via a planar excitation network 9 according to FIG. 4, the excitation network 9 being designed in such a way that two orthogonal and electromagnetically decoupled wave paths ensure the separate decoupling of linearly horizontally or linearly vertically polarized field components of the wave fields incident in the waveguide radiator. As shown in FIG. 4, the excitation network 9 consists of two strip conductors 10.1 arranged in one plane with the longitudinal dimension z1 and the transverse dimension z4, and 10.2 with the longitudinal dimension z2 and the transverse dimension z3. The stripline 10.2 is coupled in at an angle of 90 degrees with respect to the stripline 10.1, the stripline 10.1 forming the parallel axis extension of the triplate waveguide 14.1 of the longitudinal dimension x3 and the transverse dimension x4. Furthermore, the excitation network 9 consists of a conductive surface 11 with a square edge with the edge length p 1 corresponding to the dimensions indicated in FIG. 4 and the attached dimension list, the strip conductor 10.1 being separated in the middle of the edge by one of two adjacent and mutually perpendicular edges of the conductive surface 11 Gap of the gap width pβ according to the illustration 4, is arranged leading to the conductive surface 11, and the strip conductor 10.2 is centered on the other of the two adjacent and mutually perpendicular edges of the conductive surface 11 separated by a gap of the gap width p5 on the conductive surface 11 is placed in a leading position. The corresponding adaptation ensures that two spatially orthogonal and linearly polarized wave fields are coupled out in the signature of the H _{1: L} wave for each radiation exciter 3. The coupled system of waveguide radiator 8 and excitation network 9 is dimensioned in the exemplary embodiment listed for the spectral range 10.70 GHz and 12.75 GHz. Outside the hollow space of the hollow waveguide segment 13 with the inner radius rl of the hollow waveguide radiator 8, the two strip conductors 10.1 and 10.2 are each galvanically coupled to the microstrip of the asymmetrical triplate waveguide 14, the length of the triplate waveguide 14.1 being identical to the extension of the conductive shield plus Length is x2 and thus has the longitudinal dimension x3 and the transverse dimension x4 and the length of the triplate waveguide 14.2 is the dimension x5 and the transverse dimension y6. The length of the triplate waveguide corresponds to the extension of the conductive shield plus the axial length x2. The conductor length x2 thus forms the axial extension of the microstrip of the triplate waveguide 14.1 into the hollow waveguide space with the inner radius rl or the conductor length xl forms the axial extension of the microstrip of the triplate waveguide 14.2 into the hollow waveguide space with the inner radius rl. According to FIG. 3, the conductive shielding of the triplate waveguide 14.1 is implemented as a conductive border of width k2 at a height m5 above the microstrip of the triplate waveguide. According to FIG. 3, the conductive shielding of the triplate waveguide 14.2 is implemented as a conductive border of width k2 at a height m5 above the microstrip of the triplate waveguide. 4, the coupling between the triplate waveguide 14 and the active signal path 7 takes place by means of microstrip waveguide (15). Here, the microstrip waveguide 15.1 with the transverse dimension h3 axially connects to the triplate waveguide 14.1 and the microstrip waveguide 15.2 with the transverse dimension h7 axially on the triplate waveguide 14.2. The signal paths 14.1, 15.1, 14.2 and 15.2 are separated on the coupling side by defined conductive areas according to FIG. 4, which are connected by means of plated-through holes to the conductive ground plane which is galvanically separated from one another on the entire surface and on the underside by the dielectric base carrier TLY2 at a distance h2 from the microstrip waveguide 15.1 a conductive one

Strips 19.1 of strip width hl parallel to path 14.1,

15.1 is guided and at a distance h8 parallel to path 14.2,

15.2 a conductive strip 19.2 of strip width h9 is guided. Between the two conductor lines of the designated signal paths 14.1, 15.1 and 14.2, 15.2, a conductive surface 19.3 with the dimensions h5, yl, y2, y3 and rl according to FIG. 4 is arranged, which by means of through-contact with the entire surface and underside, through the dielectric base support TLY-2 galvanically separated arranged conductive ground surface is connected.

Another possible exemplary embodiment is shown in FIG. 4a. Here, the signal paths 14.1, 15.1 and 14.2, 15.2 are separated on the coupling side by defined conductive surfaces 19.1, 19.2, which are connected by means of through-plating to the conductive ground plane, which is galvanically separated from one another on the underside by the dielectric base carrier TLY2, by a distance h2 'from the Triplate waveguide 14.1 a conductive strip of strip width hl 'is guided parallel to path 14.1, 15.1 and at a distance h8' from triplate waveguide 14.2 parallel to path 14.2, 15.2 an conductive strip of strip width h9 ^{y is} guided, the two being arranged in a straight line Conductive strips along the conductive hollow waveguide segment boundary are continued in a circle with the inner radius rl 'and the outer radius r7 or are connected to one another by the circularly running conductive section likewise being arranged by means of through-contacting with the one below the dielectric base carrier and the waveguide side is connected in a circular manner by the inner surface of the hollow waveguide segment which is radially limited by the radius rl * and, according to the illustration 4, the conductive edge section 19.1 connected by means of plated-through holes to the conductive ground surface and the conductive coupling segment between the Form waveguide segment 13 and the waveguide radiator 8. Between the two conductor lines of the designated signal paths 14.1, 15.1 and 14.2, 15.2, a conductive surface with the stripe width h5 'and rl' is arranged according to the illustration, which is galvanically separated from one another by through-contacting the entire surface and underside by the dielectric base carrier TLY-2 , arranged conductive ground surface is connected.

The dielectric base carrier TLY is punched out within the boundary lines 20.1, 20.2, so that the dielectric carrier segment resulting outside the boundary lines 20 is structured within the hollow waveguide profile as the carrier of the microstrips 10.1 and 10.2 and of the conductive surface 11.

The manner in which the components of FIGS. 2 to 4 are brought together mechanically is illustrated in FIG. 8.

According to FIG. 5, the active signal path 7 consists of the input signal amplifier stages 16.1, 16.2, 16.3 and 16.4, and the polarization-selecting control circuit 17. The signal path 7 forms the switchable coupling element between the radiation exciters 3 and the converter module 5, which is the low-noise converter 21 includes. The respective input 22 of the low-noise converter 21 is activated by means of the switch 23 of the low-noise converter 21, as a result of which the radiation exciter 3.1 or 3.2 connected to this input 22 is activated. The switch 23 is activated via a 0V / 10V or 0V / 12V signal, which is preferably generated externally by the satellite receiver. The polarization control takes place by means of a likewise preferably generated 14V / 18V switching signal. The dielectric base of the stripline 10, triplate waveguide 14, microstrip waveguide 15 and the active signal path 7 is formed by means of a PTFE composition with a dielectric constant of 2.2, preferably TLY-2, with a base height of 0.79mm.

Both the n radiation exciter 3, the hollow waveguide segments 13 of the n = 2 radiation exciter 3 positioned in a cell, and the components of the active signal path 7 are arranged in a mechanically defined manner according to FIG

Component receptacle 18 is a carrier plate, which preferably consists of aluminum / aluminum die casting, brass / brass die casting or zinc / zinc die casting.

Bezuσszeichenliatβ;

1 parabolic reflector

2 radiator module

3 radiation exciters

4 coupling components

5 converter module incl. Low noise converter

6 spotlight components

7 active signal path

8 hollow wave emitters

9 coupling network

10.1 microstrip line

10.2 Microstrip line

11 square conductive surface (resonator)

12 gap between microstrip line 10 and surface 11

13 waveguide segments

14 triplate waveguides

15 microstrip waveguides 16.1 to 16.4 input signal amplifier stages

17 selective control circuit

18 Component receptacle (carrier plate) 19.1 to 19.3. Conductive surfaces which are connected to the ground surface by vias 20 Control unit

21 low-noise converters

22 inputs of the low-noise converter 23 switchers

24 mixers

25 "local oscillator" (LO)

26 signal and / or control line 27 satellite receiver unit Dimensions:

Designation measure; Describe a dimension in mm al 64.00 m4 7.00 a2 100.00 m5 2.00 a3 26.00 pi 5.00 a4 8.00 p2 5.00 a5 38.00 p3 3.00 a6 14.00 p4 3.00 bl 26.00 P5 1.70 b2 16.00 p6 1.70 cl 16.50 qi 22.50 c2 5.00 q2 14.00 c3 1.00 q 40.00 c4 75.00 q4 M3 el 22.00 rl 8.10 e2 8.00 rl '8.90 e3 M2 r2 1 1.75 e4 3.00 r3 18.20 e5 d3.2 r4 press edge 0.5x0.05 π 104.00 r5 25.00 n 80.00 r6 M3.3 deep n 73.00 r7 10.90 f4 125.00 r8 8.00 f5 47.11 sl 13.25 f6 28.26 s2 21.25 f7 18.00 s3 30.25 8 12.00 s4 33.50 f9 61.00 s5 37.00 hl 2.00 s6 8.00 h2 2.331 s7 16.00 h3 2.338 s8 23.75 h4 4.081 s9 25.75 h5 2.50 tl thickness 2.00 h6 4.08 t2 14.00 h7 2.338 t3 6.20 h8 2,331 t4 2.10 h9 2.00 xl 0.75 hl '2.00 x2 0.75 h2' 2.55 x3 3.60 h3 '1, 90 x4 1.90 h4 '2.55 x5 15.78 h5' 6.00 x6 3.80 h6 '2.55 x7 3.80 h7 1.90 x8 6.60 h8' 2.55 x9 6.60 h9 '2.00 yi 6.00 il 22.40 y2 7.31 ι2 24.40 y3 2.51 ι3 26.40 y4 2.00 ι4 32.80 y5 2.55 ι5 34.80 y6 1.90

16 40.20 y7 11.00 ι7 42.20 zl 3.95 lδ 48.00 z2 3.95 kl 13.00 z3 0.80 k2 7.00 z4 0.80 k3 7.00 z5 R7.00 k4 R3 , 50 z6 R3.67 ml 0.75 m2 1.00 m3 6.50

Claims

claims

1. reflector antenna for simultaneous reception of the radiation fields from n> 2 satellites positioned azimuthally offset from one another in orbit, the reflector antenna being a parabolic reflector (1) in particular, and a number of n radiation exciters (3) arranged on a line in the focal region of the reflector (1) ; 3.1; 3.2) for receiving polarized radiation, and the radiation exciters (3; 3.1; 3.2) are arranged in the focal area at fixed geometric distances A from one another such that one radiation exciter (3; 3.1; 3.2) each from a radiation source of a satellite is assigned and the distance A of the radiation exciters (3; 3.1; 3.2) corresponds in particular to the azimuthal offset of the radiation sources to be received from the satellites, characterized in that

- A planar excitation network (8) decouples two orthogonally and linearly polarized wave fields from each radiation exciter (3; 3.1; 3.2), and

- That by means of a coupling network (9), the outcoupled wave fields are each connected to the input of noise-matched associated input signal amplifiers (16.1; 16.2; 16.3; 16.4), and

- That optionally by means of one or more switches or the input signal amplifier (16; 17), which can be switched in the amplification and blocking mode, the output signal of an input signal amplifier (16) can be fed into a low-noise converter (21). _Λr .

16

2. reflector antenna according to claim 1, d a d u r c h g e k e n n z e i c h n e t that the low-noise converter

(21) has n inputs (22), a changeover switch (23), a mixer (24) and at least one "local oscillator (LO)" (25) for generating a comparison frequency, the output signals of the input signal amplifiers (16) of a radiation exciter ( 3.1; 3.2) can be fed into an assigned input (22) of the low-noise converter (21), and the changeover switch (23) optionally connects one of the inputs (22) to the mixer (24).

3. reflector antenna claim 1 or 2, d a d u r c h g e k e n n z e i c h n e t that any radiation exciter

(3.1; 3.2) has a hollow-wave radiator (8) of defined boundary and geometry, which is excited by means of a hollow-waveguide segment (13).

4. reflector antenna according to claim 3, characterized in that the planar excitation network (8) from two in one plane spatially orthogonal to each other microstrip conductors (10.1; 10.2) has defined geometry and boundary, the geometry and boundary the characteristic impedance of the microstrip conductor (10.1; 10.2 ) and the optimal adaptation to the downstream components is determined.

5. reflector antenna according to one of the preceding claims, d a d u r c h g e k e n n z e i c h n e t that the

Reflector antenna has a control unit (20) which controls the input signal amplifier (16), the changeover switch (23), the mixer (24) and the "local oscillator (LO)" (25).

6. reflector antenna according to claim 5, d a d u r c h g e k e n n z e i c h n e t that the reflector antenna by means of a signal and / or control line (26) in electrical connection with a satellite receiver unit

(27), and the control unit (20) communicates with the satellite receiver unit (27) and is controllable.