EP2425490A1 - Broadband antenna system for satellite communication - Google Patents

Abstract

The invention relates to an antenna for broadband satellite communication, comprising a field of primary horn-shaped emitters (1) that are connected to each other by way of a waveguide supply network (2).

Description

"Broadband Antenna System for Satellite Communication"

The invention relates to a broadband antenna system for communication between mobile carriers and satellites, in particular for aeronautical applications.

The demand for wireless broadband data transmission channels with very high data rates, especially in the field of mobile satellite communications, is steadily increasing. However, especially in the aeronautical field, there is a lack of suitable antennas, which in particular can fulfill the conditions required for mobile use, such as small dimensions and low weight. For directional, wireless data communication with satellites (eg in the Ku or Ka band), there are also extreme requirements on the transmission characteristics of the antenna systems, since interference with neighboring satellites must be reliably excluded.

In aeronautical applications, the weight and size of the antenna system is of great importance, as it reduces the payload of the aircraft and causes additional operating costs.

The problem therefore is to provide antenna systems that are as small and lightweight as possible, which nevertheless satisfy the regulatory requirements for transmitting and receiving operation when operating on mobile carriers.

The regulatory requirements for the transmission operation arise z. From standards CFR 25.209, CFR 25.222, ITU-R M. 1643 or ETSI EN 302 186. All these regulatory requirements are intended to ensure that interference with adjacent satellites can not occur in the directional transmission of a mobile satellite antenna. Typically, envelopes of maximum spectral power density are defined as a function of the distance to the target satellite. The values specified for a certain distance angle must not be exceeded in the transmission mode of the antenna system. This leads to stringent requirements for the angle-dependent antenna characteristic. As an example, in Fig. 5a, the requirement of CFR 22.209 at the angle-dependent axis width in the Kü-Bahd is shown in the direction of the azimuth (tangential to the Clarke orbit) (bold curve). As the distance from the target satellite increases, the antenna gain must drop sharply. This can be achieved physically only by very homogeneous amplitude and phase assignments of the antenna. Typically, therefore, parabolic antennas are used which have these properties. For mobile use, especially on aircraft, such antennas are not suitable. Here, to reduce the air resistance, rectangular or rectangular antenna apertures are used which have an aspect ratio height to width of at most 1: 4. Since parabolic mirrors have only very low efficiencies in such aspect ratios, for applications such. As on airplanes or cars, preferably antenna fields in question.

In the case of antenna fields, however, the known problem of the so-called "grating lobes" arises: Grating lobes are significant parasitic side lobes, which arise because the beam centers of the antenna elements which form the antenna field must have a certain distance from each other due to the design Beam angles for the positive interference of the antenna radiators and thus for the unwanted emission of electromagnetic power into undesired solid angle ranges Antenna fields (eg BJD Kraus and RJ Marhefka, "Antennas: for all applications", 3rd ed., McGraw-Hill series in electrical engineering, 2002) show that significant parasitic grating lobes only occur when the beam centers of the antenna field are less than a wavelength of the minimum useful wavelength of each other.

Since antenna fields have to have a feed network, there is the practical problem of finding network and antenna field topologies which, on the one hand, meet the above requirement for the maximum distance between the beam centers and, on the other hand, occupy as little space as possible. In addition, the feed networks must be minimally dissipative in order to realize high antenna efficiencies and thus minimum antenna sizes.

Directed satellite communication also typically uses two independent signal polarizations to increase the data rate. The antenna system must therefore be able to process two independent polarizations simultaneously. Both in the transmitting and in the receiving mode, a high polarization separation is required so that there is no mixing and thus a loss of efficiency. In the transmission mode, there are also strict regulatory requirements for the polarization separation so that it can not interfere with neighboring transponders with orthogonal polarization (see, for example, CFR 25.209 or 25.222). In the case of antenna fields, it must therefore be ensured, on the one hand, that the primary radiator elements have sufficiently good polarization separation or preservation, and, on the other hand, that there is no undesired mixing of the orthogonal polarizations in the feed networks.

Especially in aeronautical applications, the required polarization decoupling with linearly polarized signals places very high demands on the antenna system. Because such systems are typically on the Fuselage are mounted and have a two-axis positioner, the antenna aperture is always with its azimuth axis in the plane of the aircraft. The aircraft level is typically a tangential plane to the earth's surface. If the aircraft position and satellite position are not of the same geographical length, then the antenna aperture, when directed at the satellite, will always be twisted by a certain angle, which depends on the geographic length, with respect to the plane of the Clarke orbit. This so-called geographic skew can not be compensated in mobile applications by a rotation of the antenna about an axis perpendicular to the aperture plane, as is possible with stationary terrestrial antennas. Thus, an aeronautical antenna system must be able to meet the regulatory requirements despite the unfavorable length to aspect ratio even in the presence of a geographic skew up to a certain angle of rotation of typically approximately ± 35 °.

This results in the following problems for mobile, in particular aeronautical satellite antennas, which must be solved simultaneously:

1. minimum possible dimension to fulfill the regulatory requirements,

2. highest antenna efficiency with minimum weight,

3. wide bandwidth to cover the receive and transmit bands (eg Ku-band operation: 10, 7-12, 75 GHz and 13, 75-14, 5 GHz),

4. very good directional characteristics,

5. high polarization separation,

6. compensation of the geographical skew by tracking the polarization planes in the case of linearly polarized signals,

State of the art:

It is known that antennas which are designed as fields of horns, over a very high efficiency feature. If fields are fed by horns with a network of waveguides, then the attenuation of electromagnetic waves through such networks can be very small. Such a field is z. As proposed in the patent US 5243357. However, this is a pure receiving antenna (column 1, line 10 ff.). The very high polarization decoupling necessary for operation as a transmitting antenna can not be achieved with the proposed network of square waveguides. In addition, the design of the spacing between the radiator elements is comparatively large, since the square waveguides must have dimensions in the range of half the wavelength of the useful frequency for efficient waveguiding and the centers of the radiating elements are therefore far more than one wavelength apart. It is known that this leads to significant side lobes in the antenna characteristic (so-called "grating lobes") .These side lobes are harmless in pure reception mode, but a regulatory permissible transmission mode is not possible, eg CFR 25.209 or CFR 25.222 An improvement in polarization separation can be achieved by separate feed networks, for example US 2005/0146477 proposes the use of a dedicated feed network for left-hand circular and right-hand circular polarization. However, this must be serially fed in. This limits the usable bandwidth greatly, a typical Ku-band operation, eg with a reception band of 10.7 GHz to 12.75 GHz and a transmission band of 14.0 GHz up to 14.5 GHz, is not possible with such an arrangement In, for example, US 5568160 is also proposed, the distribution network food with aperture crosses. However, primary antenna elements here are square horns. The feed network is divided into a network for horizontal polarization and a network for vertical polarization. A high polarization decoupling is thus possible. However, due to the design, the radiator centers are also comparatively far apart, so that parasitic side lobes occur. The same problem occurs the z. For example, in US 6225960, WO 2006/061865 and GB 2247990 proposed arrangements. In US 6,201,508 it is proposed to apply a grid ("crossed septum", column 3, line 26) to homogenize the aperture coverage over each individual horn radiator, however, the design of the beam centers is far more than one wavelength apart and phase-parasitic sidelobes occur The device also has a significant height (extension perpendicular to the aperture plane) due to its design, making it hardly usable for mobile and in particular for aeronautical applications (in Ku band "0.37 m", column 5, line 15).

Drawings :

Fig. La-c represent the structure of the invention

Hornfeld aperture and the schematic structure of the feed networks;

Fig. 2 shows the detailed structure of the aperture surface;

Figures 3a-d show the back side of an antenna according to the invention and the detailed structure of the horn antenna array with the feed networks for two orthogonal linear polarizations;

Figures 4a-b exemplify an E-field divider and an H-divider of the feed networks;

Fig. 5a-b show a typical antenna diagram of an antenna according to the invention, Fig. 6 shows the back of an inventive

Antenna with frequency diplexers and amplifiers;

Fig. 7 illustrates a waveguide module according to the invention

Polarization tracking is; Fig. 8 shows an aeronautical antenna system with a two-axis positioner;

Fig. 9 illustrates a combined E-FeId and H-FeId divider, with the aid of which the antenna can be tracked with high precision.

The object of the invention is to provide a broadband antenna system, in particular for aeronautical applications, which, with minimal dimensions, permits a regulatory compliant transmission and reception operation and the precise alignment of the antenna with the target satellites.

This object is achieved with the invention according to claim 1. The antenna for broadband satellite communication, especially for mobile applications, consists of a field of primary horns (1) which are interconnected by a waveguide feed network (2), where the antenna consists of a number N = N _x x N ₂ primary horns with Ni> 4 N ₂ , Ni and N _{2 are} even numbers, for the total aperture area A of the antenna A = L x H with L ≥ 4 H and L <Ni λ, where λ denotes the minimum free-space wavelength of the electromagnetic wave to be transmitted or received, the primary horns allow the reception and transmission of two orthogonal linearly polarized electromagnetic waves by traveling through a rectangular aperture area a = 1 xh 1 <h and 1 <λ and in any case approximately quadratic output (3), where L = Ni 1, H = N ₂ h, and A = N _x x N ₂ xlxh = L x H, and the primary horns (1) are fed directly at their output (3) via rectangular waveguides (4, 5) such that one of the orthogonal linear polarizations is fed in and out parallel to the aperture surface and the other of the orthogonal ones linear polarizations via a waveguide septum (6) in a plane perpendicular to the aperture surface and is discharged, compressed the horns of the primary horn and have perpendicular to the aperture surface a length 1 _H <1/5 λ, the waveguide feed network (2) from a feed network for the one of the two orthogonal linear polarizations (4) and a separate feed network for the other of the two orthogonal linear polarizations (5), each of the two feed networks is constructed as a binary tree with binary E and H power dividers (7, 8), so that the last power divider at the lowest level of the binary tree is the power of two half-apertures, each with N / 2 primary horns for each of the two orthogonal polarizations separately symmetrically merges, the aperture of the antenna at least approximately the relation

Pl, j ^< P2, j <P3, j <- <Pk, j> Pk + m + 1, j> Pk + m + 2, j> Pk + m + 3, j ^> - ^> P2k + m, j, where k and m are integers and 2k + m = Ni, and the powers Pi, _j , i = l..Ni, j = l..N ₂ denote the power contributions of each primary horn, the aperture occupancy by symmetric and asymmetrical binary E and H power dividers (7, 8) in each the two feed networks for each of the two orthogonal polarizations is realized, and the entire aperture surface is covered by a Phasenegalisierungsgitter (9), wherein the meshes (10) of the Phasenegalisierungsgitters have a square dimension with edge length b and at least approximately b = 1, h = 2 b and b <λ holds, so that in the direction of Ni, the webs of the grid over the abutting edge of two adjacent horns are located and in the direction of N _2, the webs of the grid are anyway approximately exactly in the center of the aperture surface of the individual horns.

By dimensioning the horn field with a number N = Ni x N ₂ primary horns, where Ni> 4 N ₂ , and Ni and N ₂ even integers, a rectangular antenna aperture is achieved, which meets the requirements of the lowest possible height in the mobile , in particular aeronautical, use is sufficient. This dimensioning rule also ensures that upon rotation of the antenna about the main axis of the beam necessarily associated with the rotation expansion of the main lobe remains low within the +/- 35 ° angle range that is important for the application. With a length to side ratio of 4: 1, the expansion in the Ku transmission band (14 GHz-14.5 GHz) is only a few tenths of a degree.

The angular range for the geographic skew of +/- 35 ° is therefore of particular importance, because then z. B. in Ku-band, the entire North American continent with only one satellite can be covered. This leads to a significant reduction in the cost of providing a corresponding service.

If Ni and N _{2 are} even numbers, then the horn field can be efficiently fed with a bi-directional binary feed network.

The dimensioning rule for the length L of the horn field, L <Ni λ, ensures that no parasitic sidelobes occur in the azimuth direction, which are generated by a large distance of the beam centers of the primary horns. The wavelength λ must be the smallest of the wavelength occurring in the transmission mode. In Ku-band broadcasting this z. For example, the wavelength is 14.5 GHz, so that λ «2.07 cm. Only by suppressing parasitic side lobes is a regulatory permissible transmission mode possible.

The primary horns have, as shown in Fig. Ib and Fig. 2, a rectangular aperture area a, with a = 1 xh and 1 <h. The horn radiation field is then in accordance with the rules L = Ni 1, H = N ₂ h, and

A = Ni x N ₂ xlxh = L x H, where A denotes the total aperture area of the field. Thus, the aperture surfaces a of the primary horns in azimuth and elevation are close together and are aligned with their short edge in the azimuth and with their long edge in the elevation direction. With 1 <λ it is then achieved that with dense horn occupancy no parasitic side lobes in the azimuth direction can occur. If z. B. for the Ku band Transmission mode in the frequency band 14 GHz-14.5 GHz 1 <λ _max and l ^ss λ _max ^{; B} 2, 07 cm chosen, then one obtains in the inventive choice of h = 2 1 and Ni> 4 N ₂ a horn antenna field minimum dimension that can meet the regulatory requirements. Is regulatory z. B. for the 3dB width Δ required _3d B of the main lobe in azimuth 2 °, is then obtained with the known approximate formula Δ _3dB = 51 ° / L _λ (z BJD Kraus and RJ Marhefka, "Antennas: For all Applications"., 3rd Ed., McGraw-Hill series in electrical engineering, 2002, pa. 374) with L _λ = L / λ _max = N _{1 / min} a minimum number Ni, _min = 26. For the minimum number of N ₂ , N ₂ , _m inr then N ₂ , min - 4, the rule that Ni and N _{2 are} even integers, applies accordingly.

If, in addition, the rule of claim 1 is used, that the feed network is designed as a binary tree, then a horn radiation field results with Ni = 32 and N ₂ = 4, ie L «64 cm and H« lβcm. If the Aperturbelegung by symmetrical and asymmetrical binary E and H power divider now selected according to the invention, then the antenna pattern can comply with the regulatory requirements.

The sizing of the primary horns also ensures that they can have a quadratic output that supports two orthogonal linear polarizations. The square output (3) is fed by two rectangular waveguides lying in orthogonal planes. This geometry ensures effective polarization separation. In addition, the feeding tube lying in a plane perpendicular to the aperture plane is provided with a waveguide septum (6), which prevents the parasitic migration of the orthogonal polarization in this waveguide branch. The transition from the square output (3) of the primary horn to the input of the rectangular waveguide of the one linear polarization lying in the aperture plane is typically designed stepwise. This can also improve polarization separation and broadbandness. A typical embodiment of the signal extraction from the primary horns is shown in FIG. In order to keep the dimensions of the horn field as small as possible, the horns of the primary horns are compressed in the beam direction. Their length perpendicular to the aperture surface is only 1 _H <1.5 λ. This length is much smaller than the length, which is after the known

Sizing provisions for horn apertures would result and leads without Phasenegalisierungsgitter to a significant impedance mismatch to the free space wave and thus to significant reflection losses. However, if the aperture is provided with a phase-adjusting grating according to the invention, then the horns can be dimensioned according to the invention without significant losses occurring. This leads to a considerable reduction in the size of the overall antenna. The phase gating in antennas according to the invention therefore not only has the task to homogenize the phase assignment of the aperture, but also serves for the impedance matching of the primary horn to the free-space wave impedance.

In order to achieve the greatest possible polarization separation and a maximum instantaneous bandwidth, a separate feed network is provided for each of the two orthogonal polarizations. The separate feed directly from the horn output also has the advantage that the two linear orthogonal polarizations can be processed completely separately and a high-precision phase adjustment can take place. This is necessary in order to be able to achieve the accuracy required for the polarization tracking of typically <1 ° over the entire instantaneous bandwidth of typically more than 3 GHz. Also, the separation of the transmitting and receiving band is facilitated by appropriate frequency diplexer.

The construction of the feed networks as binary trees, as shown schematically in Fig. Ic, allows the use of high precision binary symmetric and asymmetric E-FeId and H-FeId power dividers (7, 8), as exemplified in Fig. 4a and Fig. 4b are shown. This high precision is necessary to get one for both Polarizations to achieve almost identical frequency response over the entire instantaneous bandwidth, which is necessary in order to achieve the necessary precision in polarization tracking can. By design, high-efficiency phasing can then be achieved by a suitable combination of waveguide pieces with coaxial cable pieces over the entire instantaneous bandwidth. In addition, this has the advantage that the amplitude and phase assignment of the aperture can be set very accurately. This is necessary in order to be able to reliably comply with the regulatory envelope over the entire required transmission bandwidth of typically more than 500 MHz. It has been shown that, in contrast to multiple power dividers, production-related tolerances in binary structures typically result in larger feeding structures. The waveguides (2) of the feed networks are dimensioned for both polarizations such that on the one hand as lossless waveguide over the entire instantaneous bandwidth is achieved, and on the other hand is minimized by a high integration density of the required space. In Ku band z. B. therefore waveguides are used whose aspect ratio is substantially smaller than the standard ratio 1: 2. In the embodiment illustrated in FIG. 1a, the waveguides (2) have an aspect ratio of only 6.5: 16. This has been shown to be sufficient to cover the entire instantaneous bandwidth of 10.7 GHz-12.75 GHz and 13.75 GHz-14.5 GHz. Compared with waveguides with standard dimensions, this results in a significant volume reduction of about 20% in the feed networks and a corresponding weight reduction. Thus, the embodiment shown in Fig. 3a-d for the Ku-band has only a total depth (extension perpendicular to the aperture plane) of about 15 cm, which is particularly for aeronautical applications of great advantage.

It is envisaged to implement the feed networks such that the line divider at the lowest level signals the two half-apertures with N / 2 primary horns respectively merges. This has the advantage that this power divider can also be designed as a combined E-FeId and H-FeId divider. Thus, not only the sum signal of the two half-apertures but also the difference signal can be tapped directly at the aperture output. If the difference signal is processed accordingly this enables the high-precision alignment of the antenna on the target satellites. For Ku-band broadcasting in the US z. For example, the CFR 25.222 standard requires a targeting accuracy of <0.2 °. This is possible with conventional methods of "open loop" tracking with the aid of position data (eg via GPS and / or inertial detectors) only for short periods, then the transmission mode must be interrupted and the antenna must be realigned with the aid of the received signal.

If, on the other hand, the aperture is constructed so that it can provide the difference signal, accuracies can be achieved with the help of a "closed loop" tracking, which are permanently << 0.2 ° in time.

In Fig. Ic, the schematic structure of the two feed networks for the two orthogonal linear polarizations is shown. Directly at the output (3) of the primary horns (1) the two polarisations are separated and fed in two separate feed networks (4) (solid lines) and (5) (dotted lines). Both feed networks are designed as binary trees with E-FeId dividers (7) and H-FeId dividers (8). At the lowest level, the signals from N / 2 primary horns are symmetrically combined. In order to measure the difference signal of the two aperture halves for both polarizations, the lowest-level divider may be implemented as a combined E-field and H-field divider (30).

It is also intended to provide the aperture with a hyperbolic amplitude assignment, which at least approximately the relation

Pl, j <P2, j <P3, j ^< - <Pk, j> Pk + m + 1, j> Pk + m + 2, j ^> Pk + m + 3, j ^> - ^> P2k + m, j o, where k and m are integers and 2k + m = Ni, and the powers Pi, j, i = l..Ni denote the power contributions of the individual primary horns. It has been found that amplitude assignments that obey this relation - if all other features according to the invention are present - produce antenna diagrams which can comply with the typical regulatory envelopes (eg defined in CFR 25.209 and ETSI EN 302 186). This class of amplitude assignments also has, in addition to the sizing specifications for the horn field, the individual primary horns and

Phase lattice of claim 1 the property that with increasing geographic skew angle no parasitic "grating lobes" occur, but the level of sidelobes in the azimuth direction over the entire instantaneous bandwidth decreases.This is a significant advantage of inventive arrangements over previously known arrangements.The effect is in Fig. 5a and Fig. 5b for a typical embodiment and for a frequency in the Ku transmission band (14.25 GHz), the angle theta designating the angle along the tangent to the Clark orbit at the point where the geostationary is located Satellite, and the skew angle is the rotation angle of the aperture perpendicular to the beam direction when the antenna is aligned with this satellite The bold curve ("FCC") marks the regulatory envelope according to CFR 25.209, which does not exceed "gain" from the antenna gain Fig. 5a shows the angular range -180 ° to + 180 °, Fig. 5b the area around the main lobe.

Aperture occupancy is realized by symmetric and asymmetrical binary E and H power splitters (7, 8) in each of the two feed networks for each of the two orthogonal polarizations, and thus is effective over the entire instantaneous bandwidth. This has the advantage that also in the receiving band a very high directivity is achieved and the parasitic irradiation of signals from neighboring satellites is greatly reduced. A typical embodiment of the feed networks is shown in Fig. Ic. Typical Embodiments of E-FeId Dividers (7) and H-FeId Dividers (8) are shown in Figures 4a and 4b.

As shown in FIGS. 1 a, 1 b and 2, it is additionally provided that the entire aperture area is covered by a phase gating grid (9), the meshes (10) of the phase gating grid having a quadratic dimension with edge length b and in any case approximately b = 1, h = 2 b and b <λ holds, so that in the direction of Ni, the webs of the grid over the abutting edge of two adjacent horns are in the direction N _2, the webs of the grid at least approximately exactly in the center of the aperture surface of the individual horns (1) are located. The dimensioning b = 1 and thus b <λ ensures that the phase gating in the azimuth follows the periodicity of the horn field and thus no additional parasitic side lobes occur. In the elevation direction, the webs of the Phasenegalisierungsgitters divide the aperture surfaces of the primary horn into two equal parts, as shown in Fig. Ia. This arrangement has the advantage that the phase occupation of the field is homogenized in both directions and that no parasitic side lobes caused by phase correlation occur even when the aperture is rotated about the main radiation direction. Due to the fact that the grating has square cells, no distortion of the E-FeId and H-FeId vectors occurs even in the presence of a geographic skew, even if, as in arrangements according to the invention, the aperture areas of the primary horns have an aspect ratio of 1: 2. Thus, the number of required primary horns in the elevation direction can be halved, since then they need not have an extension in this direction which is smaller λ. The topological requirements for the feed networks are thereby simplified considerably and an additional volume or weight reduction is achieved.

The extension of the phase gating grating (9) in the direction perpendicular to the aperture surface is typically between λ / 4 and λ / 2. This expansion is determined by the extension 1 _H horn horn horn horns, which according to the invention <1.5 λ. By varying both lengths, the instantaneous bandwidth and the impedance matching to the free-space wave can be adjusted according to the respective requirements. Arrangements according to the invention have the advantage over fields of unmodified horns that an additional degree of freedom exists for the aperture design and the antenna performance of the strongly shortened horns can thus be optimized with respect to the available installation space.

Further advantageous embodiments of the antenna are described below.

With regard to the regulatory conformity and because of the simpler manufacturing, it is advantageous if the aperture of the antenna at least approximately the relation

Pl, j ^< P2, j ^< P3, j ^< - ^< Pk, j> Pk + m + 1, j> Pk + m + 2, j> Pk + m + 3, j> - ^> P2k + tn, j where k and m are integers and m ≥ 2 k, 2k + m = Ni and in any case approximately pi, j = P ₂ k ₊ m ₊ ii, j for and the powers Pi, j, i = l..Ni, j = l..N ₂ denote the power contributions of each primary horn. With this class of trapezoidal amplitude assignments it is achieved that the number of asymmetrical power dividers of the feed networks can be minimized and still meet the regulatory requirements. The networks become considerably more fault-tolerant and easier to manufacture. For the above-mentioned example of an aperture for the Ku band with Ni = 32 and N ₂ = 4, z. B. m = 16 and k = 8, so that in principle only 8 different asymmetrical power dividers are necessary. This represents a considerable simplification. An example of a measured antenna diagram of an antenna according to the invention with a trapezoidal aperture is shown in FIGS. 5a and 5b.

A further simplification of the production can be achieved in that the aperture of the antenna at least approximately the relation Pl, j <P2, j <P3, j <- <Pk, j ⁼ Pk + 1, j> Pk + m + 1, j> Pk + m + 2, j> Pk + m + 3, j>-> P2k + m, j where k and m are integers and m ≥ 2 k, 2k + m = Ni and in any case approximately Pi, j = P _2k + m4i-i, j for i = 1..Ni / 2, and the powers Pi, _j , i = 1..Ni, j = 1..N ₂ , denote the power contributions of the individual primary horns and the powers pi _(j to p _k , j and the powers Pk + _m , j to pΣk + mj are each linearly dependent on each other, so that the pi, j to p _{k / j} and the p _{k + m / j} to p _{2k +} m, j are each at least approximately on a straight line, and the slopes of the two lines differ in any case approximately only by the sign.

A further advantageous embodiment is shown in FIG. If the antenna is used simultaneously for transmission and reception, then it is advantageous if the output of the feed network of each of the two orthogonal polarizations is connected by a waveguide (11) to a waveguide frequency diplexer (12) comprising the transmission frequency band from Receiving frequency band separates and the receiving frequency band output (13) of the two waveguide frequency diplexer (12) is in each case connected to a low-noise amplifier (14). There are provided waveguide components, since they can have the lowest attenuation and the highest isolation between the transmitting and receiving band. The receive frequency band output is each connected directly to a low noise amplifier, or preferably a waveguide, such that the parasitic noise performance through dissipative connections remains minimal.

Because of the low inherent noise of antennas according to the invention, cooled low-noise amplifiers can advantageously also be used here. In particular, with thermoelectrically cooled low-noise amplifiers or active or passive cryogenically cooled low-noise amplifiers, the receiving power of the antenna can be further increased.

FIG. 7 shows a typical embodiment of a waveguide module for polarization tracking. to Compensation of the geographic skew or other polarization rotations that are caused by corresponding movements of the antenna carrier, it is advantageous if the two orthogonal linearly polarized signals at the two outputs of the feed networks and / or at the outputs of the waveguide-frequency diplexer and / abut the outputs of the low-noise amplifiers, are fed orthogonally into one or more waveguide modules, which consist of two connected together along its axis

Hollow conductor pieces (15, 16) which can be rotated against each other about the waveguide axis (17) motor-driven (18) by means of a gear (19), so that on the feed points (20) opposite side (21) of the waveguide modules in their polarization The input orthogonal linearly polarized signals rotated linearly polarized signals can be coupled out and so the polarization of the incident waves can be reconstructed or the polarization of the waves to be transmitted can be controlled.

If the antenna used for receiving and transmitting signals in different frequency bands, which may be far apart, then it is advantageous if the antenna with a waveguide module for

Polarization tracking for the transmission band and a separate waveguide module for polarization tracking for the receiving band is equipped. The two waveguide modules can then be matched exactly to the corresponding band. As a result, a high-precision polarization tracking is achieved and caused by the frequency dispersion of the waveguide deviations can be minimized.

If the antenna is not only used for receiving and transmitting linearly polarized signals but also for receiving and / or transmitting circularly polarized signals, it is advantageous if the two orthogonally linearly polarized signals at the two outputs of the feed networks and / or at the outputs of the waveguide Frequency diplexers and / or at the outputs of the low-noise amplifier abutment with one or more 90 ° hybrid couplers are converted into orthogonal circularly polarized signals, so that the antenna also circularly polarized signals can be sent and / or received. Also, with appropriate division of the transmit and receive signals, simultaneous operation with all four possible orthogonal polarizations (2 × linear + 2 × circular) is possible both in transmit and in simultaneous receive mode. An arrangement according to claim 1 thus has the highest possible variability.

In particular, for mobile applications, it is advantageous if the antenna is mounted on the elevation axis of a two-axis positioner and the waveguide modules to compensate for polarization rotations and / or the 90 ° hybrid coupler for the reconstruction of circularly polarized signals mounted on the azimuth platform of the positioner and the antenna and waveguide modules and / or the 90 ° hybrid couplers are interconnected with flexible high frequency cables. This arrangement of aperture and RF modules reduces the space required and facilitates integration, especially in aeronautical applications. A typical arrangement with a two-axis positioner is shown in FIG. The Hornfeld aperture with feed network (22) is mounted on the elevation axis (23) and can be aligned by means of the elevation motor (24) and the elevation gear (25) in the elevation direction. With the aid of the azimuth motor (26), the antenna can be rotated about the azimuth axis (27). In the azimuth axis (27) a high-frequency rotary feedthrough with typically two channels is integrated. The electronics boxes (28) and (29) typically contain the control electronics for the positioner and additional high-frequency modules, such. B. modules according to claim 4 for polarization tracking. Also, boxes (28) and (29) may contain the processing electronics for high-precision tracking of the antenna, such as the electronics for processing the difference and sum signals of a combined E-field and H-field splitter. Because of the extreme environmental conditions to which particular hull-mounted aeronautical antennas are exposed, it may be advantageous if all or part of the antenna components are completely or partially silvered or coppered, all or part of the components are soldered and / or welded together and / or or glued, the antenna is provided with the exception of the aperture surface from the outside wholly or partially with a protective layer against the ingress of moisture, and in the plane between the primary horns (1) and the Phasenegalisierungsgitter (9) or in the plane of the horn outputs (3 ) a high frequency permeable waterproof film is introduced, which prevents the penetration of moisture into the primary horns and the waveguide feed network. Particularly in mobile applications, antennas according to the present invention typically consist of light metals such as aluminum or metallized plastic materials for reasons of weight reduction. To increase the antenna efficiency, it is advantageous to silver or copper these materials, since silver and copper have a very high RF conductivity. In order to ensure the required RF-tightness even at extreme rapid temperature changes, it is advantageous to solder at least critical parts of the aperture, to weld, or to glue, with the bonding typically electrically conductive adhesives are used. In addition, it may be necessary to protect the aperture against penetrating moisture, in particular condensation. Since it has been shown that the Phasenegalisierungsgitter must not be galvanically connected to the primary horns, it is advantageous to attach a necessary protective film between the plane of the primary horns and the Phasenegalisierungsgitter or in the plane of the horn outputs (3). This also has the advantage of very high mechanical stability even with strong changes in ambient air pressure.

However, to protect against moisture ingress can be applied to the Phasenegalisierungsgitter also from the outside a suitable RF-transmissive material. suitable Materials are in particular thin sheets of closed-cell foams (eg polystyrene, Airex, etc.). These plates can be glued and / or screwed to the surface of the phase gating grid with suitable flexible or viscoplastic adhesives, thus reliably preventing the ingress of moisture or other undesirable substances into the antenna. In addition, it is advantageous to provide a hydrophobic and / or fungicidal finish on the surface of the protective material since this prevents the unwanted settlement of biological organisms ("biological slimes", fungi) which can have a negative effect on the high-frequency properties, as well as direct foaming of the openings of the phase gating grid ,

Furthermore, it may be advantageous, especially for aeronautical applications, to provide the feed network with ventilation openings. Such vents may prevent condensate from accumulating inside the antenna, which may degrade the high frequency characteristics of the antenna. The ventilation openings are preferably attached to the long edge of the waveguide of the feed network, since only small high frequency currents flow. The dimension of the vents is typically much smaller than the wavelength for which the antenna is designed. However, the ventilation openings can also be mounted in the protective film of the Phasenegalisierungsgitters or in the Phasenegalisierungsgitter covering material, in which case larger openings can be realized. To prevent the ingress of dirt or other undesirable substances such. For example, to prevent oil, it may be advantageous to provide the vents with only water vapor permeable membranes (eg, oleophobic Gore membranes).

Fig. 9 shows a typical embodiment of a combined E-FeId and H-FeId divider, with the aid of which the antenna can be tracked with high precision. An advantageous Embodiment of the antenna is characterized in that the last waveguide power divider each of the two feed networks (4,5), which combines the signals of the two aperture halves with each N / 2 primary horns designed as a combined E and H divider (30) is such that both the sum signal (31) of the two symmetrical aperture halves and the difference signal (32) of the two symmetrical aperture halves is applied to this waveguide four-port and both the sum signal and the difference signal can be derived separately for each of the two orthogonal polarizations. Combined E-FeId and H-field divisors, so-called "magic teas", are four-element elements which, due to their geometric properties, provide both the sum signal of two supplied signals and the differential signal, due to the binary structure of the feed networks Horn field apertures invention possible, instead of the last binary power divider to install a "magic tea". The difference signal can then be used either alone or together with the sum signal for high-precision alignment of the antenna on the target satellites. Since the difference signal disappears with exact alignment and the sum signal with exact alignment becomes maximum, z. For example, the quotient of the signal powers Pdifferenz / Psumme an extremely pronounced minimum (a so-called "zero") with exact alignment.Due to deviations from the exact alignment of the value of the quotient increases sharply and can be used for precise and fast tracking of the antenna the phase of the RF signal at the differential gate (32) has a zero crossing with exact alignment, so that the sign of the phase position indicates the direction in which the antenna must be tracked in. Since the high-precision tracking in satellite antennas, in principle, only along the Clarke orbit - In the azimuth direction, it is sufficient to divide the aperture in two halves in the azimuth direction In the elevation direction, open loop tracking is typically sufficient with the aid of position data and / or inertial detector data. If the last power divider of the feed networks designed as a combined E-FeId and H-FeId divider (30), it is advantageous if the difference gate (32) of the combined E- and H-divider is equipped with a transmission band-cut filter, the prevents the penetration of transmission signals in the differential branch and the difference gate (32) is connected via the transmission band rejection filter with a low-noise amplifier. Since only the receiving signal must be used for high-precision tracking of the antenna by means of the signal of the differential gate, the low-noise amplifier which amplifies this signal can be efficiently protected by a transmission band-cut filter from overdriving by the typically very strong transmission signal. Typically, this is a waveguide barrier filter is used because this class of components has only a very low attenuation. It is also advantageous to connect the low-noise amplifier directly to the transmit band blocking filter, preferably also through waveguides, as this can minimize signal loss. If the received signal strong enough then but also embodiments are conceivable in which the low-noise amplifier with a high-frequency cable, z. B. a coaxial line is connected to the transmission band blocking filter.

In particular, for mobile applications of the antenna, it is advantageous if the differential signals and / or a part of the sum signals of the two symmetrical aperture halves are forwarded to a processing electronics, which evaluates the strength and / or the phase position of the differential signals and / or the sum signals and these to the Passing control electronics of the antenna positioner, so that the control electronics can track the antenna so that the difference signal is minimal and so the antenna remains aligned with the target satellites when the antenna carrier moves relative to the target satellite. By design, the antenna is then optimally aligned with the target satellites when the receive signal at the difference gate of the combined E-field and H-field divider becomes minimal. This optimality criterion can thereby in a simple way for high-precision tracking of the antenna at moving antenna carriers are used to be processed by a suitable electronic unit and forwarded to the controller of the antenna positioning system. Since the difference signal is permanently available in time, very high sampling rates and thus very fast tracking are possible even with very fast moving antenna carrier. Since the phase of the difference signal has a rapid zero crossing with optimum alignment with the target satellites, it is advantageous to also evaluate the phase position of the difference signal and to use for tracking. Typically, this allows an even higher precision in the tracking can be achieved than when only the strength of the difference signal is used. Since the antenna diagram of the Differenztors has two main lobes, which can show in the worst case on neighboring satellites, it is also advantageous to compare the difference signal in its strength and / or its phase position with the sum signal to exclude the parasitic interference of neighboring satellites in the tracking , In principle, by appropriate processing of the sum signal, since the antenna diagram of the Summentors has only a single, well-defined main lobe, parasitic interference terms are eliminated in the difference signal. This can be z. B. take place in that the difference signal is phase-aligned projected to the sum signal.

In order to track the antenna with high precision, in principle both beacon signals of the satellite and normal transponder signals can be used. In this case, a satellite beacon typically consists of a narrowband (<1 kHz) CW-like signal, while a normal transponder typically emits a broadband signal (in Ku-band, for example, 30 MHz), which is coded by phase coding (eg. QPSK) an information content is imprinted. In both cases, it may be advantageous to increase the signal to noise ratio of the difference gate signal and / or the summent signal by limiting the noise bandwidth. Also, the processing of high-frequency signals is facilitated by the fact that the processing electronics contains one or more fixed frequency mixer and / or one or more controllable frequency-variable mixer and one or more frequency filters for the difference signals and / or the sum signals, with which the difference signal or a part of the difference signal and / or the sum signal or a part of the sum signal in a defined baseband can be converted and processed there. By using controllable frequency-variable mixers ("frequency synthesizer"), the frequency range or transponder used for tracking can be specifically controlled.

For satellite signals of suitable strength, the difference signal and the sum signal in the baseband can be directly evaluated. For this purpose, it is advantageous if the strength of the difference signal and / or the sum signal in the baseband is measured with a suitable electronic circuit and transferred to the control electronics of the antenna positioner. In this case, standard electronic components, such as suitable amplifiers or power detectors, can be used, which are available at low cost for typical base bands in the MHz range.

In weak satellite signals or unfavorable satellite configurations, it may be advantageous if the difference signal and / or the sum signal in the baseband is digitized with an analog-to-digital converter and forwarded to a processor which has suitable evaluation methods to measure the strength and / or the Phase position of the difference signal and / or the sum signal to determine, and passes this information to the control electronics of the antenna positioner. By digitizing the signals, the software-controlled evaluation and thus the flexible adaptation to the respective conditions is possible. The processor can be z. B. consist of a specially programmed FPGA or a simple freely programmable arithmetic unit. To improve the signal quality z. B. software-implemented controllable filter can be used with the help of which the noise bandwidth can be optimized. If the antenna signals are converted into a baseband for the purpose of high-precision tracking, digitized and forwarded to a processor, then it is advantageous in particular for aeronautical applications in which the antenna carrier (eg the aircraft) can move at very high speed. if the processor has an evaluation method with which the double frequency shift of the difference signal and / or of the sum signal occurring during rapid movements of the antenna carrier can be compensated. In contrast to the electronic implementation of a

Doppler tracking electronics, software-implemented tracking can be implemented relatively inexpensively in a suitable processor if the signals are already in digitized form. Since the maximum Doppler shift can be calculated over the maximum velocity of the antenna carrier, it is possible to configure a software-implemented filter accordingly. Then z. B. using an FFT ("Fast Fourier Transform") determines the current frequency of the signal, the noise bandwidth adjusted accordingly and the strength of the signal are measured.

Since the antenna aperture in mobile and in particular aeronautical applications typically can not be rotated about the beam axis, it may be advantageous if a polarization rotation of the difference signal and / or the sum signal of the two aperture halves due to the spatial position of the antenna carrier is reflected by one or more waveguide modules Claim 4 or in that the processor of the processing electronics has a suitable evaluation method can be compensated. As a result, a mixing of the signals of different polarization and thus a signal interference, which may affect the precise tracking prevented. In principle, this is depending on the application, two methods, the use of waveguide modules according to claim 4 and the software processing, available. Since the position of the antenna carrier, z. B. via GPS, typically known is, the polarization rotation can be calculated in a simple manner and can then be transferred to the control of the waveguide module or to the processor.

If the signals of the difference gate and the sum gate are present in digitized form, then it has been shown that it is advantageous if the evaluation method of the processor is to multiply two or more temporally successive values of the amplitude of the baseband difference signal and these products over a certain time .DELTA.t sum up to a sum Si, in each case two or more temporally successive values of the amplitude of the baseband sum signal to multiply and sum up these products over a certain time .DELTA.t to a sum S ₂ , after the time period .DELTA.t the quotient S1 / S ₂ and / or another suitable function f (Si, S ₂ ), the value obtained thereby by the method of the smallest distance or another suitable method with the standard curve f _N (δ, Si, S ₂ ), thereby determining the value of the deviation angle δ and applying it to d The control electronics of the antenna positioner to pass. With the aid of this method even difference signals can be processed for which the noise power is higher than the signal power. If the time interval Δt is selected appropriately, all the noise components disappear in the multiplication correlator and the strength of the typically generalized periodic signal becomes visible. If the sum signal is processed accordingly, then z. B. the quotient S ₁ / S2, regardless of the respective signal amplitudes, which is of great advantage in changing signal strengths. The signal strength-independent standard curve f _N (δ, Si, S2) can be calculated by simple mathematical methods. However, for precise tracking, the standard curve may also be measured using the method and a suitable satellite transponder or beacon and then stored. Because of its simplicity, the method can also be used in z. B. analog electronics can be implemented. Since, in particular, aeronautical antennas are typically mounted under an aerodynamically optimized radome, it may be necessary due to space constraints to modify the rectangular shape of apertures according to the invention. In particular, in order to maintain the necessary distance to the underside of the radome, a rounding of the corners of the aperture (horns with powers p _u , PiN ₁ / PiN ₂ / P _N2N1 in Fig. Ib) are required. It has been found that a change in the horn edges or a reduction in the horn opening and even the complete removal of horns horns at the corners of the aperture hardly affects the performance of the antenna and its positive characteristics with respect to the antenna characteristics.

In one embodiment, not shown, the antenna is constructed according to the invention, up to a total of Ni / 2 primary horns, which are located at the edge of the aperture are not physically realized, or realized in its border changed or reduced, the corresponding cells of the Phasenegalisierungsgitters are modified accordingly in that the edges of the cells continue to lie on the edges of the primary horns, the aperture coating according to the invention is realized only for complete lines of the field of primary horns containing Ni primary horns (see Fig. Ib) and the binary tree structure of the two feed networks (see Fig. Ic) is correspondingly cropped in the case of the absence of primary horns.

Claims

Claims : Antenna for broadband satellite communications, in particular for mobile applications, consisting of a field of primary horns interconnected by a waveguide feed network, characterized in that the antenna consists of a number N = Ni x N ₂ primary horns with Ni > 4 N ₂ , Ni and N _{2 are} even integers, for the total aperture area A of the antenna A = L x H with L ≥ 4 H and L <Ni λ, where λ is the minimum free-space wavelength of the transmit or receive electromagnetic wave, the primary horns allow the reception and transmission of two orthogonal linearly polarized electromagnetic waves by having a rectangular aperture area a = 1 xh with 1 <h and 1 <λ and an approximately square output, where L = Ni 1, H = N ₂ h, and A = Ni x N ₂ xlxh = L x H holds, and the primary horns directly at their output over rectangle ige waveguide are fed so that the one of the orthogonal linear polarizations parallel to the aperture surface and is discharged and the other of the orthogonal linear polarizations via a waveguide septum in a plane perpendicular to the aperture surface and removed, the horns of the primary horn upset and perpendicular to the aperture surface have a length 1 _H <1.5 λ, the waveguide feed network consists of a feed network for one of the two orthogonal linear polarizations and a separate feed network for the other of the two orthogonal linear polarizations, each of the two Meteoric networks is constructed as a binary tree with binary E and H power dividers, so that each of the last power divider at the lowest level of the binary tree, the power of two half-apertures with each N / 2 primary horns for each of the two orthogonal polarizations separated together symmetrically separated In any case, the aperture of the antenna approximates the relation Pl, j <P2, j <P3, j <- <Pk, j> Pk + m + 1, j ^> Pk + ra + 2, j ^> Pk + ra + 3, j>-> P2k + m, j where k and m are integers and 2k + m = Ni, and the powers Pi, j, i = l..Ni, j = l..N2 denote the power contributions of each primary horn, the aperture bias is symmetric and asymmetric binary E and H power dividers in each of the two feed networks for each of the two orthogonal polarizations, and the total aperture area of one Phasenegalisierungsgitter is covered, wherein the meshes of the Phasenegalisierungsgitters have a quadratic dimension with edge length b and at least approximately b = 1, h = 2 b and b <λ applies, so lie in the direction Ni, the webs of the grid over the abutting edge of two adjacent horns and in the direction of N _2, the webs of the grid are in any case approximately exactly in the middle of the aperture area of the individual horns. 2. Device according to claim 1, characterized in that the aperture of the antenna at least approximately the relation Pl, j ^< P2, j <P3, j <- <Pk, j ⁼ Pk + 1, j ⁼ Pk + 2, j ⁼ - ⁼ Pk + ra, j ^> Pk + m + 1, j> Pk + m + 2, j ^> Pk + m + 3, j ^> - ^> P2k + ra, j, where k and m are integers and m ≥ 2 k, 2k + m = Ni, and in any case approximately pi, j = P2k ₊ m ₊ ii, j for i = l..Ni / 2, and the powers p ±, _j , i = l..Ni, j = l..N ₂ denote the power contributions of the individual primary horns. 3. Device according to one of the preceding claims, characterized in that the output of the feed network of each of the two orthogonal polarizations is connected in each case by a waveguide with a waveguide-frequency diplexer which separates the transmission frequency band from the reception frequency band and the Empfangsfrequenzband- output of the two waveguides Frequency diplexer is each connected to a low-noise amplifier. 4. Device according to one of the preceding claims, characterized in that the two orthogonally linearly polarized signals at the two outputs of the feed networks and / or at the outputs of the waveguide frequency diplexer and / or at the outputs of the low-noise Amplifier abut orthogonally in one or more waveguide modules are fed, which consist of two interconnected along its axis waveguide pieces which can be rotated against each other around the waveguide axis motor driven, so that on the opposite side of the feed points of the waveguide modules in their polarization with respect to the fed orthogonal linear polarized signals rotated linearly polarized signals can be coupled out and so the polarization of the incident waves can be reconstructed or the polarization of the transmitted waves can be controlled. 5. Apparatus according to claim 4, characterized in that the antenna with a waveguide module for Polarization tracking for the transmission band and a separate waveguide module for polarization tracking for the receiving band is equipped. 6. Device according to one of the preceding claims, characterized in that the two orthogonally linearly polarized signals present at the two outputs of the feed networks and / or at the outputs of the waveguide frequency diplexer and / or at the outputs of the low-noise amplifier with one or more 90 ° hybrid couplers are converted into orthogonal circularly polarized signals so that circularly polarized signals can also be transmitted and / or received with the antenna. 7. Device according to one of the preceding claims, characterized in that the antenna is mounted on the elevation axis of a two-axis positioner and the waveguide modules according to claim 4 and / or the 90 ° hybrid coupler according to claim 5 mounted on the azimuth platform of the positioner and the antenna and waveguide modules and / or the 90 ° hybrid couplers are interconnected with flexible high frequency cables. 8. Device according to one of the preceding claims, in particular for aeronautical applications, characterized in that all or part of the components of the antenna are completely or partially silvered or copper-plated, all or a part of the components soldered together and / or welded and / or glued, the antenna with the exception of the aperture of Externally provided in whole or in part with a protective layer against the ingress of moisture, and in the plane between the primary horns and the Phasenegalisierungsgitter or in the level of Hornausgänge a waterproof film is introduced, the penetration of moisture into the primary horns and the waveguide feed network prevented. 9. Device according to one of the preceding claims, characterized in that the last waveguide power divider each of the two feed networks, which combines the signals of the two aperture halves with each N / 2 primary horns is designed as a combined E and H divider, so on Both the sum signal of the two symmetrical aperture halves as well as the difference signal of the two symmetrical aperture halves is applied to this waveguide four-port, and both the sum signal and the difference signal can be derived separately for each of the two orthogonal polarizations. 10. The device according to claim 9, characterized in that the difference gate of the combined E and H divider is equipped with a transmission band-cut filter, which prevents the penetration of transmission signals in the differential branch and the difference gate on the transmission band notch filter with a low-noise amplifier connected is. 11. Device according to one of the preceding claims, in particular for mobile applications, characterized in that the difference signals and / or a part of the sum signals of the two symmetrical aperture halves are forwarded to a processing electronics, which the strength and / or the phase position of the differential signals and / or evaluates the sum signals and these to the Control electronics: the antenna positioner passes so that the control electronics can track the antenna so that the difference signal is minimal and so the antenna remains aligned with the target satellites when the antenna carrier moves relative to the target satellite. 12. The device according to claim 11, characterized in that the processing electronics for the differential signals and / or the sum signals includes one or more fixed frequency mixer and / or one or more controllable frequency-variable mixer and one or more frequency filters, with which the difference signal or a part of Difference signal and / or the sum signal or a part of the sum signal can be converted into a defined baseband and processed there. 13. The apparatus according to claim 12, characterized in that the strength of the difference signal and / or the sum signal measured in the baseband with a suitable electronic circuit and transferred to the control electronics of the antenna positioner. 14. The apparatus of claim 12, characterized in that the difference signal and / or the sum signal is digitized in the baseband with an analog-to-digital converter and forwarded to a processor which has suitable evaluation method to the strength and / or the phase position of the differential signal and Determine / or the sum signal, and passes this information to the control electronics of the antenna positioner. 15. The apparatus of claim 14, in particular for aeronautical applications, characterized in that the processor has an evaluation method with which occurring during rapid movements of the antenna carrier Doppler frequency shift of the difference signal and / or the sum signal can be compensated. 16. Device according to one of the preceding claims, characterized in that a conditional by the spatial position of the antenna carrier polarization rotation of the difference signal and / or the sum signal of the two aperture halves by one or more waveguide modules according to claim 4 or in that the processor of the processing electronics has a suitable evaluation method can be compensated. 17. The apparatus of claim 14, characterized in that the evaluation method of the processor is to multiply two or more temporally successive values of the amplitude of the baseband differential signal and to sum these products over a certain time .DELTA.t to a sum Si, two in each case or to multiply more temporally successive values of the amplitude of the baseband sum signal and to sum these products over a certain time .DELTA.t to a sum S ₂ , after the time period .DELTA.t the quotient Si / S ₂ and / or another suitable function f (Si , S ₂ ), to compare the value obtained thereby with the method of the smallest distance or another suitable method with the standard curve f _N (δ, Si, S ₂ ) known by calibration measurement or calculation, thereby increasing the value of the deviation angle δ determine and transfer this to the control electronics of the antenna positioner. 18. Device according to one of the preceding claims, characterized in that up to a total of Ni / 2 primary horns, which are located at the edge of the aperture, physically unrealized, or realized in its border changed or reduced, the corresponding cells of the Phasenegalisierungsgitters so in that the edges of the cells continue to lie on the edges of the primary horns, the inventive aperture according to claim 1 or claim 2 is realized only for complete lines of the array of primary horns containing Ni primary horns and the binary tree structure of the two Supply networks is pruned in the case of the absence of primary horns accordingly.