EP3482457B1 - Phase-controlled antenna array - Google Patents

Description

The invention relates to a phase-controlled group antenna, in particular for the GHz frequency range and for use on mobile carriers such as motor vehicles, aircraft or ships.

In mobile applications, the phase control of the group antenna has the function of always optimally aligning the main beam of the group antenna with a target during the spatial movement of a mobile carrier. In many cases, a permanent radio link to the target antenna must be reliably maintained even when the wearer moves quickly.

With the help of the phase control, however, a moving target can also be tracked with a stationary or mobile group antenna, as is the case with radar applications.

It is known that the antenna diagram of stationary antenna groups can be spatially changed with the aid of variable, controllable phase shifters and the main beam can thus be pivoted in different directions.

The phase control elements change the relative phase position of the signals that are received or sent by various individual members of the group antennas. If the relative phase position of the signals from the individual antennas is determined using the Phase control elements adjusted accordingly, then the main lobe ("main beam") of the antenna directional diagram of the group antenna points in the desired direction.

The currently known phase actuators are mostly composed of non-linear solids ("solid state phase shifters"), mostly ferrites, microswitches (MEMS technology, binary switches), or liquid crystals ("liquid crystals"). However, all these technologies have the disadvantage that they often lead to a considerable loss of signal, since part of the high-frequency power is dissipated in the phase control elements. In particular in the case of applications in the GHz range, the antenna efficiency of the group antennas is greatly reduced as a result.

This represents a considerable problem, particularly for group antennas which are to be used on mobile carriers, because antennas with the highest possible efficiency are required in these applications because of the limited installation space available. The antennas must be as small and light as possible, which cannot be achieved with the known phase controls.

In addition, conventional phase control elements must always be accommodated in the feed networks of the group antennas, which typically makes such group antennas very heavy or their thickness very large.

In contrast, particularly for applications on fast moving carriers such as airplanes and trains, small and light, low profile antenna systems are desired.

In addition, phased array antennas that use conventional phase actuators are very expensive. This prevents use in particular for civil applications above 10 GHz.

The requirements for precise control of the antenna pattern of the group antennas represent a further problem. If the group antennas are used in radio relay applications with satellites, then there are strict requirements for the regulatory conformity of the antenna pattern. For each main beam direction, the diagram of the regulatory mask must obey the transmission mode. This can only be reliably guaranteed if both the amplitude and the phase of each individual antenna element of the group antenna are known at all times.

However, none of the currently known technologies for phase actuators allows the reliable instantaneous, i. immediate determination of the phase position of the signal after the phase control element, which is available without further calculation. For this it would be necessary to be able to reliably determine the state of the phase control element at any time. However, this is practically impossible with solid-state, MEMS or liquid-crystal phase shifters.

From the DE 37 41 501 C1 is known feed system for an antenna that can transmit different polarized waves. The feed system uses a fixed 90 ° phase shifter and a movable 180 ° phase shifter, so that the phase position of both shafts can be adjusted to one another. From the US 6 822 615 B2 an antenna array with phase shifters between a first and a second part of the antenna array is known. Finally shows the DE 10 2010 014 916 B4 a group antenna with a feed network that forms coherent groups of individual radiators.

Furthermore, the WO 02/084797 A1 a phased array antenna with a plurality of circularly polarized radiator elements, the array antenna comprising movement means which are used for the independent and angular rotation of at least a part of the radiator elements.

1. 1. die exakte Ausrichtung und Steuerung des Hauptstrahls der Gruppenantenne erlaubt,
2. 2. die exakte Steuerung und Kontrolle der relativen Phasenlage der Signale der verschiedener Antennenelemente der Gruppenantenne ermöglicht,
3. 3. zu jedem Zeitpunkt die instantane Bestimmung der Phasenlage und der relativen Amplitude des an einem Antennenelement der Gruppenantenne anliegenden Signals und damit zu jedem Zeitpunkt und in jedem Zustand der Gruppenantenne die Bestimmung ihres Antennendiagramms zulässt,
4. 4. keine oder nur sehr geringe Verluste hat,
5. 5. ein niedriges Profil und ein geringes Gewicht besitzt, und
6. 6. kostengünstig realisierbar ist.

The object of the invention is therefore to provide a phase-controlled group antenna, in particular in the GHz frequency range and in particular for use on mobile carriers, which

1. 1. allows the exact alignment and control of the main beam of the group antenna,
2. 2. enables the exact control and monitoring of the relative phase position of the signals of the various antenna elements of the group antenna,
3. 3. at any point in time the instantaneous determination of the phase position and the relative amplitude of the signal applied to an antenna element of the group antenna and thus allows the determination of its antenna diagram at any point in time and in any state of the group antenna,
4. 4. has no or only very low losses,
5. 5. Low profile and light weight, and
6. 6. Can be implemented cost-effectively.

This object is achieved by a phase-controlled array antenna according to the invention with the features of claim 1. Advantageous further developments of the invention can be found in the dependent claims, the description and the figures.

The phase-controlled array antenna according to the invention comprises at least four phase-controlled antenna elements (1) connected via at least one feed network (12). The Antenna elements each comprise a waveguide radiator (2) with a signal decoupling or coupling (8), a phase control element (3) which is rotatably mounted in the waveguide radiator (1), a holder (4) and at least two polarizers (5), wherein each of the at least two polarizers (5) can convert a circularly polarized signal into a linearly polarized signal. Furthermore, the antenna elements comprise a connection element (6) and a drive unit (7) mounted on a carrier (9), which is connected to the phase control element (3) via the connection element (6) in such a way that the drive unit (7) controls the phase control element ( 3) can rotate around an axis (11) of the waveguide radiator (2). The group antenna also includes a computing unit (13) which is connected to the drive unit (s) (7) of the phase-controlled antenna elements (1) via control lines (10) and which sets the rotation of the respective phase control elements (3).

An exemplary spatial arrangement of the elements of the group antenna is shown in Fig. 1 shown. Here, for example, four antenna elements (1) are arranged in a row. However, the antenna elements (1) can also be arranged with a larger number and / or in several rows, that is to say two-dimensionally. A computing unit (13) controls the entire group antenna. Each of the antenna elements (1) has its own drive unit (7). As shown later, this can also be further simplified by using common drive units (7) for several antenna elements (1).

The basic functionality of a phase-controlled antenna element is shown in Fig. 2 shown. A wave (14a) incident in the waveguide radiator (2) of the antenna element (1) with circular polarization and phase position ϕ is converted into a wave by the first polarizer (5a) of the phase control element (3) transformed with linear polarization (14b). This wave of linear polarization is converted back into a wave with circular polarization (14c) by the second polarizer (5b) of the phase control element (3).

If the phase control element (3) is now rotated by an angle Δθ with the aid of the drive unit (7) and the connecting element (6), the polarization vector (14b) of the linear wave between the two polarizers (5a) and (5b) rotates in one plane perpendicular to the direction of propagation with. Since the polarizer (5a) also rotates, the circular wave (14c), which is generated by the second polarizer (5b), now has a phase position of θ + 2 Δθ. The circular wave (14c) with phase position ϕ + 2 Δθ can then be decoupled from the waveguide radiator (2) of the antenna element (1) or coupled into the waveguide radiator (2) with the aid of the signal decoupling or coupling (8).

The drive unit (7) is mounted on a carrier (9) and is supplied with the necessary energy via supply lines and with the information necessary for the rotation through the angle Δθ via control lines (10) with the aid of the computing unit (13).

Due to the design of the phase control of the antenna element (1), the dependence of the phase angle difference between the outgoing (14c) and incoming (14a) circular wave on the rotation of the phase control element (3) is strictly linear, continuous and strictly 2n periodic. In addition, any desired phase rotation or phase shift can be set continuously by the drive unit (7).

Since the phase control element (3) is a purely passive component from an electrodynamic point of view, it does not have any contains nonlinear components, its function is completely reciprocal. This means that a shaft which runs from bottom to top through the phase control element (3) is rotated in its phase in the same way as a shaft which runs from top to bottom through the phase control element (3).

The phase position of a signal sent or received by the waveguide radiator (2) of the antenna element (1) can thus be set as desired. Simultaneous transmission and reception is also possible.

The signal decoupling or coupling (8) is shown in FIG Fig. 2 designed as a microstrip line (8) on a substrate (81). For this purpose, the waveguide radiator (2) of the antenna element (1) is provided with a cutout at the point of coupling or decoupling, which allows the microstrip line including the substrate to be introduced into the waveguide radiator (2). So that the high-frequency currents flowing on the inner walls of the waveguide radiator (2) are not disturbed, electrically conductive vias (83) are provided which establish electrical contact between the top and bottom of the waveguide radiator (2). In addition, a recess (82) is provided in the substrate (81) through which the axis (6), which connects the drive unit (7) to the phase control element (3), can be guided.

If several phase-controlled antenna elements (1) are now connected to one another, a phase-controlled group antenna according to the invention is created. This is in Fig. 3 shown schematically
Fig. 3a shows schematically the group antenna, Figure 3b the associated feed network (12). It consists of two networks (12a) and (12b), each of which processes orthogonal polarization.

The signals from all four antenna elements (1) are brought together or distributed in transmission mode via the feed networks (12a) and (12b), which contain the inputs and outputs (8a) and (8b).

The drives (7) of the individual phase controls are controlled by a computing unit (13) which e.g. can be a microprocessor which is connected to the signal lines (10) which connect all drive units to the computing unit.

The couplings in and out (8a) and (8b) and the feed networks (12a) and (12b) are designed as microstrip lines (8a, b) on a substrate, analogous to the illustration in FIG Fig. 2 .

The signal decoupling or coupling (8) is also designed in two parts as a pin-shaped, orthogonal microstrip line (8a) and (8b) on separate substrates.

Such embodiments can be advantageous if two signals of orthogonal polarization are to be received and / or transmitted simultaneously with the group antenna. Phase imbalances can also be compensated if the signals are processed in an orthogonal system.

If the phase controls (3) are now set with the aid of the arithmetic unit (13) so that there is a constant relative phase difference Δ Sign between the signals of the individual elements, then the shows Main beam of the group antenna in a certain direction dependent on the phase difference Δϕ.

Since the amplitude relationships of the transmitted and received signals of the individual antenna elements (1) are precisely known via the feed network (12) and the phase position of each of these signals can also be precisely determined via the phase controls (3), the antenna diagram of the group antenna is in every state of the Group antenna (ie also at any point in time) determined completely deterministically.

If the required computing power is available in a microprocessor or at another point in the antenna system, it is therefore possible to analytically calculate the entire antenna diagram at any point in time with very high accuracy. In particular with regard to the regulatory conformity of the antenna diagram, which is typically required in civil applications, this represents a significant advantage of arrangements according to the invention.

Even if the group antennas contain several thousand individual antennas, e.g. is typically the case in the frequency range above 10 GHz, the corresponding antenna diagram can be calculated very precisely with the aid of a Fast Fourier Transformation (FFT) with relatively little computing power. Correspondingly fast FFT algorithms are well known.

The weight of the phase control (phase control element (3), connection (6) and drive unit (7)) of the individual antenna elements (1) is typically very small. If the polarizers (5) are implemented in thin-film technology on thin HF substrates and the holder is made from closed-cell foam, the phase control typically only weighs a few grams. Therefore, only very small and light actuators, such as micro-electric motors, are required for the drive unit. The weight of such micro-electric motors is also in the gram range.

The weight of an individual phase control, especially in the frequency range above 10 GHz, is then only a few grams, which results in a total weight of the entire phase control of the group antenna of only a few kilograms, even with group antennas with a thousand individual radiators. This is particularly advantageous in aircraft applications, where the weight should be as low as possible.

In addition, there is the very low dissipation of the phase control according to the invention. The heat input of the phase control elements is negligible because of the very low ohmic losses. If electric motors are used as drive units, their efficiency is typically> 95%, so that the drive units also cause practically no heat input. In addition, the power consumption of micro-motors, for example, is only in the mW range, so that the power requirement of the phase controls is only a few watts, even with group antennas with a thousand individual radiators.

This is a further advantage of the phase control according to the invention. Even in the case of group antennas with many thousands of individual radiators, active cooling is not required, neither in transmission nor in reception. In contrast to this, in the case of group antennas which use conventional semiconductor phase shifters or MEMS phase shifters, complex active cooling is essential, at least in transmission mode, because of the high losses.

The feed networks (12) of the phased array antenna can as in Figure 3b shown schematically consist of microstrip lines on a suitable RF substrate. To minimize losses, these microstrip lines can also be designed as suspended microstrip lines, that is to say in a coaxial construction. Parts of the feed networks (12) can also consist of waveguides, which can further reduce the losses.

So it is e.g. It is advantageous to connect groups of phase-controlled antenna elements (1) within the group antennas via microstrip lines and then to interconnect these groups further via waveguides. Such hybrid feed networks (12) then allow a high density of antenna elements. If the long ways, e.g. In the case of large group antennas, which are designed using waveguide technology, the losses are nevertheless limited.

Due to its design, the wave impedance of the antenna element (1) is completely independent of the relative phase position of the incoming and outgoing wave. In the case of antenna elements which are controlled in their phase position with the aid of non-linear phase shifters such as semiconductor phase shifters or liquid crystal phase shifters, this is typically not the case. There the wave impedance depends on the relative phase position, which makes these components difficult to control.

The waveguide radiator (2) is preferably designed in such a way that it contains at least one cylindrical waveguide section. This ensures that a cylindrically symmetrical electromagnetic oscillation mode (mode) of circular polarization can develop in its interior, which is dependent on the Polarizers (5) can be transformed into a linear polarization mode.

Both the waveguide termination of the waveguide radiator and its opening (aperture), on the other hand, do not necessarily have to have a circular cross section. Depending on the type of coupling or coupling (8), the waveguide termination can e.g. be conical or stepped on one side. The aperture of the waveguide radiator can e.g. when used in two-dimensional antenna fields e.g. can also be designed conical (horn antenna), square or rectangular.

Since cylindrically symmetric modes are also found in waveguides with non-circular cross-sections, e.g. elliptical or polygonal cross-sections, but other designs of the waveguide radiator are also conceivable.

For applications above 10 GHz, it can be advantageous for densely packed group antennas to design the waveguide radiator as a round waveguide, since such waveguides allow the highest packing density and also support cylinder-symmetrical cavity modes.

In order to improve the antenna gain of the phase-controlled antenna element, it can also be advantageous to design the waveguide radiator as a horn radiator.

In addition, the dimensional design of the waveguide radiator (2) for a specific operating frequency band is carried out using the known methods of antenna technology.

The axis of rotation (11) of the phase control elements (3) preferably lies in the axis of symmetry of the respective cylindrical Waveguide piece, which each waveguide radiator (2) preferably contains.

The polarizers (5a) and (5b) are preferably mounted in the holder (4) perpendicular to the axis of rotation (11) and parallel to one another.

For the rotation of the phase control element (3) a rotation of a quarter circle (-45 ° to + 45 °) is typically sufficient to realize a swivel range of -90 ° to + 90 ° with a group antenna and thus to cover the entire hemisphere above the antenna .

The phase control works practically without losses, since with a suitable design the losses induced by the polarizers (5a, b) and the dielectric holder (4) are very small. At frequencies of 20 GHz, for example, the total losses are less than 0.2 dB, which corresponds to an efficiency of more than 95%. Conventional phase shifters, on the other hand, typically already have losses of several dB at these frequencies.

With regard to its high-frequency properties, the phase-controlled array antenna according to the invention can therefore hardly be distinguished from a corresponding antenna array without phase control.

It is known, for example, that dielectrically filled horn radiators, in particular at frequencies greater than 20 GHz, are used in antenna fields because of their high antenna efficiency. If such antenna fields are implemented as phase-controlled group antennas according to the invention, then the HF properties, in particular antenna gain and antenna efficiency, change Antenna fields advantageously not despite the additional phase control.

If the drive unit (7) is equipped with an angular position encoder, or if it already gives angular position itself (such as some piezo motors), the phase position of the shaft (14a) emitted by the Holleiter emitter can be determined instantaneously and exactly at any time.

Due to the simple structure of the phase control element (3) and the fact that only very simply structured drives (7) are required for the quarter-circle rotation, the phase control can be implemented very inexpensively. Large phased array antennas with many thousands of antenna elements are also easily possible.

As drive units (7), for example, both inexpensive electric motors or micro-electric motors, as well as piezomotors, or simple actuators made of electroactive materials come into question.

The drive elements are preferably SMD components which can be soldered directly onto a suitable circuit board as a carrier (9). The supply and control lines (10) can then be designed as microstrip lines, which allows a high integration density.

The connecting element (6) is preferably designed as an axle and is preferably made of a non-metallic, dielectric plastic material such as plastic. This has the advantage that cylindrical cavity modes are not, or only very slightly, disturbed when the axis is attached symmetrically in the waveguide radiator (1).

If coaxial modes are used to operate the waveguide radiator (2), metallic axes can, however, also be used.

However, it is also conceivable that the drive unit (7) e.g. next to the waveguide radiator (2) and the connecting element (6) e.g. consists of a belt that is fed through small openings in the side of the waveguide radiator and thus drives the phase control element.

It is also conceivable that the drive unit (7) controls the phase control element (3) in a contactless manner, e.g. via a rotating magnetic field, rotates. For this purpose, e.g. a magnetic rotator can be attached above the termination of the waveguide radiator, which then acts together with the rotating magnetic field as a connecting element (6), if e.g. Parts of the polarizer are made of magnetic materials.

The polarizers (5a, b) can e.g. consist of simple, flat meander polarizers which are applied to a conventional carrier material. These polarizers can be manufactured by known etching processes or by additive processes ("circuit printing").

As in Fig. 4 shown, the at least two polarizers (5a) and (5b) preferably have a shape symmetrical to the axis (11), so that they can be accommodated in a simple manner in the cylindrically symmetrical waveguide section of the waveguide radiator.

The in Fig. 4 The polarizer (5a, b) shown is designed as a meander polarizer. Multi-layer meander polarizers are advantageous here, since these can have large frequency bandwidths and thus enable broadband operation.

As is known to the person skilled in the art, however, there are also a large number of other possible embodiments of polarizers for electromagnetic waves which can transform a wave of circular polarization into a wave of linear polarization.

E.g. Embodiments are conceivable in which the signal polarization is not converted by plane polarizers but by structures spatially distributed in the holder (e.g. septum polaristors). For the function of the invention, it is only important that these structures first transform a wave with circular polarization incident into the waveguide radiator (2) into a wave with linear polarization and then transform it back into a wave with circular polarization.

For the holder (4) e.g. closed-cell foams with low density, which are known to have very low HF losses, but plastic materials such as polytetrafluoroethylene (Teflon) or polyimides are also used. Because of the small size of the phase control element in the range of one wavelength, especially at frequencies above 10 GHz, the HF losses remain very small here too with appropriate impedance matching to the corresponding electromagnetic mode in the waveguide radiator (1).

Since, from an electrodynamic point of view, the dimensional design of the phase control element (3) at a certain operating frequency is similar to the dimensional design of the waveguide radiator (2) at a certain operating frequency, the phase control element (3) can typically easily be attached inside the waveguide radiator (2).

In any case, even if the dimension of the waveguide radiator (2) is chosen to be very small, the phase control element (3) can be made so small that it is in the waveguide radiator (2) by selecting the dielectric constant for the material of the holder (4). Takes place.

Thus, according to the known design rules for a waveguide radiator, its minimum diameter is typically in the range of one wavelength of the operating frequency. The expansion of the waveguide radiator in the direction of the incident waves is typically a few wavelengths of the operating frequency.

Since the polarizers (5a) and (5b) and their spacing (e.g. half a wavelength) from one another are also designed according to the wavelength of the operating frequency using the known impedance matching methods, the dimensions of the phase control element are always in the range of the dimensions of the waveguide radiator.

At a frequency of 20 GHz e.g. the dimensions of the phase control element (3) are typically in the range smaller than one wavelength, i.e. approx. 1cm x 1cm. If the holder (4) is designed as a dielectric filling body and the dielectric constant is selected to be correspondingly large, then much smaller form factors can also be implemented. The ohmic losses then increase slightly, but are still only in the percentage range.

Figur 5

eine quadratische Gruppenantenne,

Figur 6

ein Antennenelement mit zusätzlichem Polarisator,

Figur 7

ein Antennenelement mit Füllkörper,

Figur 8

ein Antennenelement mit drehbarem zusätzlichen Polarisator,

Figur 9

eine Gruppenantenne mit gemeinsamen zusätzlichen Polarisator, und

Figur 10

eine Gruppenantenne mit gemeinsamer Antriebseinheit für mehrere Antennenelemente.

Further exemplary embodiments of the invention are explained in the following figures, which show:

Figure 5

a square group antenna,

Figure 6

an antenna element with an additional polarizer,

Figure 7

an antenna element with packing,

Figure 8

an antenna element with a rotatable additional polarizer,

Figure 9

a group antenna with common additional polarizer, and

Figure 10

a group antenna with a common drive unit for several antenna elements.

In Fig. 5 an exemplary embodiment of a square array antenna with 8 x 8 = 64 phase-controlled antenna elements (1) is shown schematically.

The antenna elements (1) are arranged in a two-dimensional field and the control lines (10) of the drive units (7) of the individual phase-controlled antenna elements (1) are connected to a microprocessor unit (13) as a computing unit.

With the help of such two-dimensional arrangements of phase-controlled antenna elements (1), the main lobe of the antenna diagram of the antenna field, which forms a two-dimensional group antenna, can be pivoted in any direction in the hemisphere above the field.

The alignment of the antenna beam ("antenna beam") takes place in a diagram shown in FIG Fig. 3a analogous way in that the drive units (7) of the individual antenna elements are controlled by the microprocessor unit (13) in such a way that the phase actuators of the individual antenna elements (1) are rotated so that there is a certain relative phase relationship between the antenna elements (1) of the group antenna .

The precision of the alignment of the main beam is very high because the phase position of the signals emitted or received by the individual antenna elements (1) can be set as desired and in principle also as precisely as desired with the aid of the phase control.

This represents another significant advantage of such array antennas e.g. in comparison with phase-controlled group antennas which use binary phase shifters. In principle, with binary phase shifters, the phase position of the individual signals can only be set granularly in certain steps. A highly precise alignment of the antenna diagram is not possible in principle.

The direct reception or transmission of signals with linear polarization by the phase-controlled group antenna is possible through the use of special phase-controlled antenna elements (1).

One such antenna element is in Fig. 6 shown schematically and characterized in that in the waveguide radiator (2) of the phase-controlled antenna element (1) in front of the phase control element (3) at least one further polarizer (15) is attached, which can transform signals with linear polarization into signals with circular polarization, and after Phase control element (3) and at least one further polarizer (16), which can transform signals of circular polarization into signals of linear polarization, is attached upstream of the coupling-out (8).

The phase control element (3) also consists of the holder (4) and the polarizers (5a) and (5b) and has a Drive unit (7) which is connected via the connecting element (6) to the phase control element (3) or the holder (4) in such a way that the phase control element (3) can be rotated in the horn antenna (2).

Because the first additional polarizer (15) converts an incident signal with linear polarization into a signal with circular polarization, the phase control element (3) can easily perform its function.

The polarizer (16), which is attached after the phase control element (3) and before the decoupling (8), then transforms the signal of circular polarization generated by the phase control element (3) back into a signal of linear polarization, which is generated by a signal corresponding to linear modes designed decoupling (8) can be decoupled directly.

The function of the arrangement is again completely reciprocal. In the case of transmission, the coupling (8) excites a linear mode in the waveguide radiator (2), which is transformed into a circular mode by the second polarizer (16). With the phase control element (3), a phase position which is dependent on the angle of rotation of the phase control element (3) about the axis (11) is impressed on this circular mode. The circularly polarized signal with the set phase position, which leaves the phase control element (3), is transformed by the first additional polarizer (15) into a signal with linear polarization and the impressed phase position and emitted by the waveguide radiator (2) of the antenna element (1).

In the Fig. 6 The arrangement shown also works for two simultaneously incident orthogonal linear polarizations if the signal decoupling or coupling (8) accordingly for two orthogonal linear modes, e.g. as in Fig. 3 shown.

The simultaneous sending and receiving of signals of the same or different polarization is also possible.

An embodiment of the in Fig. 6 antenna element shown is in Fig. 7 shown schematically.

The signal decoupling or coupling (8) is analogous to the illustration in FIG Fig. 2 designed in one piece as a microstrip line on a substrate.

The additional polarizers (15) and (16) are each embedded in a dielectric filling body (17a) or (17b) and are typically permanently mounted in the waveguide radiator (2). The waveguide termination below the coupling-out or coupling-in (8) is also filled with a dielectric filler (17).

This structure has the advantage that the entire interior of the waveguide radiator (2) is filled with a dielectric, typically of the same type, so that mode discontinuities cannot occur.

The polarizer (16) and its dielectric filler body (17a), like the dielectric filler body (17), have a recess for the connecting element (6) analogous to the substrate (cf. Fig. 2 (81)) so that the connecting element (6) can be rotated freely.

Analogous to the in Fig. 3a and Figure 3b illustrated two-part coupling (8a, b) can also in the embodiment of Fig. 7 the coupling (8) are designed in two parts for two orthogonal linear modes.

In order to compensate for a polarization rotation of an incident wave, it is also conceivable to make the first additional polarizer (15) rotatable and to equip it with an independent drive so that this polarizer (15) turns independently of the phase control element (3) in the waveguide radiator (2) the axis (11) can be rotated.

Such an arrangement is particularly advantageous when, in mobile arrangements, the movement of the carrier causes a rotation of the polarization vector of the incident wave relative to the array antenna fixedly mounted on the carrier.

Since such a polarization rotation is generally independent of the phase rotation, which is used for spatial alignment of the antenna beam, the rotation of the polarizer (15) must be able to take place independently of the rotation of the phase control element (3).

A corresponding embodiment is shown in Fig. 8 shown schematically.

The first additional polarizer (15) is rotatably mounted in the waveguide radiator (2) and connected to its own drive (19) with the aid of an axis (18) so that the drive (19) moves the polarizer (15) around the axis (11) can turn.

The independent rotation of the polarizer (15) from the rotation of the phase control element (3) is shown in FIG Fig. 8 realized in such a way that the axis (6) which connects the phase control element (3) with its drive (7) is designed as a hollow axis. In This hollow axis is the axis (18) which connects the polarizer (15) with its drive (19).

Since the plane of polarization of a wave with linear polarization is only defined in an angular range of 180 °, an angular range of -90 ° to + 90 ° is required for the rotation of the polarizer (15), i.e. a semicircle turn is sufficient.

The second additional polarizer (16) is firmly attached in the waveguide radiator (2), since its alignment determines the alignment of the linear mode which is coupled out or coupled in by the coupling out or coupling (8). The fixed alignment of the polarizer (16) therefore depends on the position of the coupling-out or coupling-in (8).

If the coupling out or coupling (8) is implemented in two parts, for example as in the embodiment of FIG Fig. 3a and 3b Then the polarizer (16) can also be dispensed with, since the circularly polarized signal generated by the phase control element contains in principle all the information of the incident wave. To recombine the original signal, a 90 ° hybrid coupler, for example, can then be used, in which the signal divided into the components of the coupling (8a) and (8b) is fed.

Due to the construction of the phase control according to the invention, only a single 90 ° hybrid coupler is then required for the phase-controlled group antenna, which e.g. can be integrated into the feed network (12) at the base of the feed network (12) of the group antenna.

Since polarization rotations of an incident wave of linear polarization affect all antenna elements of a phased array antenna in the same way, there is also one Embodiment conceivable in which a rotatable polarizer is attached above the group antenna.

An exemplary embodiment of a group antenna which consists of phase-controlled antenna elements (1) according to the invention and which is equipped with a polarizer (21) which is rotatably located above the antenna group is shown in FIG Fig. 9 shown schematically.

The group antenna of the Fig. 9 consists of 52 antenna elements (1), which are arranged in a two-dimensional field in a circle. A common polarizer (21) is rotatably mounted above the antenna group and covers a plurality, in particular also all antenna elements (1).

The polarizer (21) is designed here as a meander polarizer and can be rotated about an axis (22) which is perpendicular to the antenna field.

If a wave of linear polarization now strikes the arrangement, then the polarizer (21) can be rotated so that it transforms this wave of linear polarization into a wave of circular polarization.

In the case of a meander polarizer, this is an angle of rotation at which the axes of the meander lines enclose an angle of 45 ° with the polarization vector of the incident wave. At other angles of rotation, however, a wave with a general elliptical polarization would arise.

The signal transformed in this way into a signal of circular polarization is fed into the phase-controlled antenna elements (1) of the group antenna, which, for example, correspond to those in the Fig. 3 , 7th or 8th Embodiments described are designed, fed. The phase position of the signal can then be adjusted again in the manner already described via the phase control elements (3) of the individual antenna elements (1) and the main beam of the antenna group can be controlled accordingly.

Another embodiment of the invention is shown in FIG Fig. 10 shown schematically. The group antenna consists of a two-dimensional array of 16 phase-controlled antenna elements (1), which are arranged in a square. In contrast to the previous exemplary embodiments, however, each antenna element does not have its own drive (7) here, but rather 4 antenna elements lying in a row have a common drive. The drives (7) are connected to each of the phase control elements (3) of the 4 antenna elements (1) with the aid of the connecting elements (6).

The top row has no drive. The phase control elements of these antenna elements are set the same and thus determine the reference phase ϕ. Since the alignment of the main beam of the group antenna only depends on the relative phase positions of the signals of the antenna elements, such an arrangement is quite generally possible.

With this arrangement, however, the directions in which the main beam of the array antenna can be swiveled are restricted to a plane that is perpendicular to the two-dimensional antenna field and parallel to the one in Fig. 10 designated line AA '. The main beam can only be swiveled in this plane.

If the phase control elements of the different rows of the antenna group are now adjusted with the aid of the drives (7), that there is a fixed relative phase difference of Δϕ between the rows, then the antenna beam of the group antenna swivels away from the normal of the two-dimensional field in this plane. The swivel angle is again proportional to the phase difference Δϕ.

For many applications, however, the restriction of the swivel range to one plane does not have to represent a restriction of the functional scope of the group antennas formed in this way.

If the group antenna is mounted on a rotatable support (23) and can be rotated about an axis which is perpendicular to the antenna field, then the main beam of the arrangement can again be steered in every direction in the hemisphere above the arrangement.

Antriebe erforderlich. Hinzu kommt dann lediglich noch ein Antrieb für die Drehung der Gruppenantenne als Ganzes.The advantage of the embodiment is that the number of drive units (7) required is greatly reduced. In general, there are no longer N drives if N denotes the number of antenna elements in a group antenna, but only $\sqrt{N}$

Drives required. In addition, there is only a drive for rotating the group antenna as a whole.

The embodiment can therefore be advantageous for applications in which it is only a matter of the lowest possible profile of the group antenna and in which no excessive beam swiveling speeds are required.

Since the swivel range lying in a plane perpendicular to the antenna field encompasses an angular range of -90 ° to + 90 °, the angular range required for rotating the antenna group is also only 180 °. So no complete rotation is necessary. Complex high-frequency rotary feedthroughs are not required.

In a simple, not shown embodiment, the antenna group is e.g. Mounted on a flat bed bearing and is rotated by an external drive and the signal lines as well as the supply and control lines of the drives are guided to the antenna group with the help of flexible cables and cable wraps.

The drive units (7) of the individual rows can rotate the axes of the phase control elements (3) of the antenna elements (1) in a row, for example with the aid of toothed wheels or drive belts. Worm gears or screw drives are also possible, for example, as connecting elements (6). Reference number Antenna elements 1 Waveguide radiator 2 Phase actuator 3 bracket 4th Polarizer 5a, 5b Connecting element 6th Drive unit 7th Signal out / in, microstrip line. 8, 8a, 8b carrier 9 Control lines 10 axis 11 Feed network 12, 12a, 12b Computing unit, microprocessor 13 wave 14, 14a, 14b, 14c Additional polarizers 15, 16 Packing 17, 17a, 17b Axis of the additional polarizer 18th Drive the additional polarizer 19th Polarizer for several antenna elements 21st Axis of the polarizer 22nd Rotatable carrier 23 Substrate 81 Recess 82 Via 83

Claims (15)

1. Phase-controlled array antenna, comprising at least four phase-controlled antenna elements (1) connected via at least one feed network (12), wherein a phase-controlled antenna element (1) consists of

   • a waveguide radiator (2) having a signal output coupling and/or input coupling (8),

   • a phase shifter (3) fitted rotatably in the waveguide radiator (2) and containing a mount (4) and at least two polarizers (5a, 5b), wherein each of the at least two polarizers (5a, 5b) can convert a circularly polarized signal into a linearly polarized signal in order to transform a wave (14a) having circular polarization and a phase angle ϕ that is incident in the waveguide radiator (2) into a wave (14b) having linear polarization by means of a first polarizer (5a) of the at least two polarizers (5a, 5b) of the phase shifter (3) and to transform said wave (14b) having linear polarization back into a wave (14c) having circular polarization by means of a second polarizer (5b) of the at least two polarizers (5a, 5b) of the phase shifter (3),

   • a connection element (6), and

   • a drive unit (7) fitted on a carrier (9) and connected to the phase shifter (3) via the connection element (6) in such a way that the drive unit (7) can rotate the phase shifter (3) about an axis (11) of the waveguide radiator (2), such that upon rotation of the connection element (6) and thus also of the two polarizers (5a, 5b) by an angle Δθ, the polarization vector of the linear wave (14b) between the two polarizers (5a, 5b) is correspondingly rotatable by the angle Δθ in a plane perpendicular to the direction of propagation and the wave (14c) having circular polarization thus has a new phase angle of ϕ + 2 Δθ, and

   • a computing unit (13), which is connected to the drive units (7) of the phase-controlled antenna elements (1) via control lines (10) and sets the rotation of the respective phase shifters (3).
2. Array antenna according to Claim 1, wherein the waveguide radiator (2) is embodied as a horn radiator.
3. Array antenna according to either of the preceding claims, wherein the polarizers (5a, 5b) are fitted perpendicularly to the axis (11) of the waveguide radiator (2) and parallel to one another on the mount (4) .
4. Array antenna according to any of the preceding claims, wherein the polarizers (5a, 5b) are embodied as meander polarizers.
5. Array antenna according to any of the preceding claims, wherein the polarizers (5a, 5b) have a shape that is symmetrical with respect to the axis (11) of rotation.
6. Array antenna according to any of the preceding claims, wherein the connection element (6) is embodied as a spindle connecting the phase shifter (3) to the drive unit (7).
7. Array antenna according to any of the preceding claims, wherein the drive unit (7) contains an electric motor or a piezomotor or actuator, wherein the actuator comprises electroactive materials.
8. Array antenna according to any of the preceding claims, wherein the connection element (6) or the drive unit (7) is equipped with an angular position encoder.
9. Array antenna according to any of the preceding claims, wherein the signal output coupling and/or input coupling (8) contains a looped or pin-shaped metallic structure, is embodied using microstrip line technology and/or is embodied in a bipartite fashion in such a way that two orthogonal modes of the waveguide radiator (1) are able to be coupled in and/or out separately.
10. Array antenna according to any of the preceding claims, wherein the waveguide radiator (2) contains at least one additional dielectric filling body that wholly or partly fills the waveguide radiator (2).
11. Array antenna according to any of the preceding claims, wherein at least one additional polarizer (15, 16), which can convert a signal having linear polarization into a signal having circular polarization, is fitted in the waveguide radiator (2) between an aperture of the waveguide radiator (2) and the phase shifter (3) and/or between the phase shifter (3) and the signal output coupling and/or input coupling (8).
12. Array antenna according to Claim 11, wherein the at least one additional polarizer (15) fitted between the aperture of the waveguide radiator (2) and the phase shifter (3) is fitted rotatably in the waveguide radiator (2), and has an additional drive (19) and an additional spindle (18), such that the drive (19), with the aid of the spindle (18), can rotate the polarizer (15) about the axis (11) of the waveguide radiator (2) independently of the phase shifter (3).
13. Array antenna according to any of the preceding claims, characterized in that the phase-controlled antenna elements (1) are fitted in a one- or two-dimensional antenna array.
14. Array antenna according to any of the preceding claims, comprising a polarizer (21) fitted rotatably about a plurality of phase-controlled antenna elements (1), such that an incident wave having linear polarization is able to be converted into a wave having circular polarization.
15. Array antenna according to any of the preceding claims, wherein the phase-controlled antenna elements (1) of the array antenna are arranged in rows, wherein each row of antenna elements (1) has a common drive unit (7) and a plurality of connection elements (6), such that the phase shifters (3) of said row are rotatable by said drive element (7).

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