DE102008008387A1 - Antenna system for mobile satellite communication - Google Patents

Abstract

Specifically, an antenna system that is electronically adjustable in azimuth and elevation angle has been developed. To control the directional diagram no mechanical components are used. The system is modular and can be adapted to different antenna gain requirements by scaling, using more or fewer antenna modules. In addition, the division into tiling-like modules allows an adaptation of the aperture of the antenna system to curved surfaces. The figure shows a functional block diagram of the entire antenna system.

Description

Technical field to which the invention belongs:

• Mobile communications, antenna technology and satellite communications.

Prior art with references:

satellite signals are typically received by parabolic antennas. These antennas are characterized by high profit and simple structure. In mobile Applications prove these mechanical solutions but as unwieldy and depending on the implementation of maintenance.

From antenna theory it is known that high-frequency signals can be received by means of planar array antenna arrangements (eg. Phased Array Antenna Handbook, Artech House 1994, ISBN 0-89006-502-0 such as EP1 146 592 A1 ). This technology can be used in both stationary and mobile applications.

in the the present case are only antennas for mobile applications of relevance.

by virtue of the relative movement of the carrier vehicle and the satellite the necessity arises the receiving characteristic of the array antenna to track. Here, a tracking must be carried out in azimuth and in the elevation direction. When using linearly polarized signals is also a polarization tracking necessary.

To address this problem, semi-mechanical planar solutions have been developed ( EP 1 202 387 B1 stationary application). For tracking in azimuth turntables are used ( WO 2004 / 045020A1 ; US D493164S . WO002004079861A1 ). In the elevation direction electronic phase shifters are used.

In WO 2005 / 067098A1 and US5835057A Antennas for mobile satellite reception are described. However, these are mechanical realizations. While in US005835057A a mechanically moved parabolic mirror is described in WO 2005 / 067098A1 used as an antenna aperture planar structures that are mechanically moved in azimuth and elevation.

In WO 2005/004284 A1 and WO 2004 / 045020A1 Planar patch antenna arrays are described in multilayer structure. Where in both cases, the directional diagrams are fixed. at WO 2005 / 004284A1 perpendicular to the antenna surface, at WO 2004 / 045020A1 in a fixed elevation angle of 45 °.

In WO 2004/079861 A1 a planar antenna for the reception of satellite signals is described. The control in azimuth direction is done by mechanical rotation, while the control in elevation direction by electronic beam swinging via phase shifter. This patent application forms the closest prior art.

1 problem description

For contemporary and future communication applications in the field of mobile satellite communications will be for the integration of the antenna functionality into the host vehicle (eg land vehicles, aircraft or maritime vehicles) compact constructed, flat, mechanical controls avoiding and to the Vehicle surface customizable, cost-effective Solutions needed.

Around Flat, cost-effective antenna systems for mobile Implementing applications are the following problem areas to solve.

Simplification of the structure

In In the intended field of application, it is important to have a low cost To work out a solution. Here are low production costs an important role. It is possible an automated, according to standard procedures aligned manufacturing process needed.

Large frequency bandwidth

Around the entire useful range with respect to the signal emissions It is necessary to cover a broadband design of the antenna system (10.75 GHz to 12.75 GHz corresponding to 20% relative Bandwidth with respect to the midband frequency of 11.75 GHz).

scalability

The field strengths of the satellite signals to be received in the service volume have different level values depending on the satellite system and application. In order to enable optimum adaptation to the particular application, it is necessary to adapt the reception characteristics (reception quality) of the antenna. The reception quality is with the dimensions or in the case of planar array antennas of the number of antenna elements 10 dependent.

Avoid the use of mechanical moving parts

Mechanically Moving parts lead to a certain maintenance operational. In addition, the moving parts or their Stellelemente different dynamic loads according to the respective operational environment.

Selection and tracking of the polarization

Dependent The type of polarization of the transmitter results in various requirements on properties of the receiving antenna. In Europe, the satellite signals of Ku band emitted as linear polarizations. This kind the transmission signal is optimized for stationary applications. In case of mobile application it is necessary the polarization direction the receiving antenna (horizontal polarization, vertical polarization) to select and during the relative movements tracked by carrier vehicle and satellite.

In North America, the satellite signals of the Ku band in circular Polarization emitted. For circular polarization is a tracking relative movements between the carrier vehicle and the satellite unnecessary.

Reduction in the number of electronic components

G_ANT:

Gewinn der Antenne

G_ES:

Gewinn des Antennenelements 10

G/T:

Verhältnis von Gewinn (G) zu Systemrauschtemperatur (T)

S/N:

Verhältnis von Signalleistung (S) zu Rauschleistung (N)

In order to achieve a sufficient signal quality (G / T or S / N) to the system requirements, a certain antenna gain is required. For array antennas, this gain is the number of antenna elements used 10 and their individual characteristics (G _ANT = 10 × LOG (M × N) + G _ES; N = number of elements in the x direction, M = number of elements in the Y direction). According to the theoretical specifications for combining the individual antennas, a relative distance of 0.5 wavelengths must be observed. For each individual element is then assigned a phase weighting. This leads to a high number of required components.

G _ANT :

Win the antenna

G _ES :

Gain of the antenna element 10

G / T:

Ratio of gain (G) to system noise temperature (T)

S / N:

Ratio of signal power (S) to noise power (N)

at a reduction of the phase weighting components may be the requirement after the distance of the actuators of 0.5 wavelengths no longer be respected. This leads to tilting the receiving characteristic to the occurrence of so-called 'Grating Praise '. These are unwanted additional main lobes, which interference signals can couple into the receiving system and the signal power to noise power ratio (S / N) deteriorate.

swivel range

Around the largest possible operational space to support is one over classic constructions (Elevation: +/- 55 °) extended swivel range (Elevation: +/- 70 °) of the antenna reception characteristic required.

2 problem solving

The The problem described above has been described by the following solved constructive measures and into a functional Antenna system implemented according to claim 1, according to the claims 17 and 18 is used and according to the methods of claims 19 and 20 applies.

Specifically, an antenna system which can be electronically adjusted in azimuth and elevation angle ( 1 ) developed. To control the directional diagram no mechanical components are used. The system is modular and can be adapted to different antenna gain requirements by scaling, using more or fewer antenna modules. In addition, the division into tiling-like modules allows the aperture of the antenna system to be adapted to curved surfaces. In 2 a functional block diagram of the entire antenna system is shown.

The entire antenna system is hierarchically structured, modular and consists of the following main assemblies with the following reference numbers:

1

TrackSat ^TM antenna system

2

antenna

3

casing

4

antenna module

5

ROW_PCB, Zeilensummierschaltung

6

COL_PCB, Spaltensummierschaltung

7

mounting frame

8th

Sub-array

9

signal Processing Element (SPE)

10

antenna element (AE)

In 3 the hierarchical structure of the main modules is shown. In 4 the structural integration of the individual modules is shown.

2.1 Brief description of the illustrations

It demonstrate:

1 : Definition of the coordinate system

2 : Function overview of the antenna system 1

3 : Hierarchy of Antenna Modules

4 : Antenna modules

5 : Layered construction of an antenna element 10

6 : Structure of the antenna element 10 (Section EF)

7 : Data Sheet ro4350: Rogers Corporation One Technology Drive, PO Box 188, Rogers, CT 06263-0188, 10/2007

8th : Data Sheet ro4450: Rogers Corporation One Technology Drive, PO Box 188, Rogers, CT 06263-0188, 09/2007

9 : Sub-array 8th : View from above

10 : Balanced supply of antenna elements 10 a sub-array 8th : (Bottom view), implementation 1

11 : Balanced supply of antenna elements 10 a sub-array 8th : (Bottom view), implementation 2

12 : Summing network in the SPE 9 for H-polarization

13 : Summing network in the SPE 9 for V-polarization

14 : Summing network in the SPE 9 for H-polarization

15 : Summing network in the SPE 9 for V-polarization

16 : switched azimuthal radiation pattern of the sub-array 8th (four AE)

17 : switched azimuthal radiation pattern of the sub-array 8th (four AE)

18 : switched azimuthal radiation pattern of the sub-array 8th (four AE)

19 : switched azimuthal radiation pattern of the sub-array 8th (four AE)

20 : Functional block diagram for the polarization control of the sub-array 8th

21 : Settings of the control signals for polarization control of the sub-array 8th

22 : Functional block diagram for the phase control of the sub-array 8th

23 : Layer structure of the SPE 9

24 : Layer construction SPE 9 (Section GH)

25 : Antenna module 4 : View from above - emission direction A _S

26 : Definition of sub-array 8th Labels within an antenna module 4

27 : Signal summation of the antenna module 4 (16 sub-arrays 8th : A11 to A44)

28 : Definition of the antenna module 4 Labels within the antenna system 1

29 : Signal summation of the antenna system 1 (Antenna module 11 to MN)

30 : Mobile reception of TV satellite signals (DVB-S)

31 : Mobile reception of satellite signals for broadband Internet access

3 description

3.1 Single radiating element

The single radiating element is as a layered structure of microstrip Patch antennas realized with slot coupling.

Around the requirements for ease of manufacture and flat design to ensure the use of the microstrip Patch antenna technology used for the present application has been modified.

microstrip Patch antennas are made by planar structures on printed circuit board materials realized, which allows a simple physical structure. It can apply to methods of manufacturing electronic multilayer printed circuit boards be resorted to.

In terms of electrical properties, microstrip patch antennas prove to be efficient but narrowband emitters. Typical achievable bandwidths are 2% - max. 5% relative to the center fre frequency. In the present application, however, at least 17% (Ku band: 10.75 GHz to 12.75 GHz) is required.

By Dielectrics with a large layer thickness can increase this bandwidth but leads to unwanted side effects, like surface waves.

Therefore, for the realization of a broadband antenna element 10 a combined structure of several superimposed individual patches selected. The patch on the first layer must be 4% larger than the one below. Here, the layer thickness of the dielectric materials was chosen so low that no surface waves are generated. A slot coupling technique connects the patches to the feed line. This allows to optimize the bandwidth by additional degrees of freedom in the design of the geometry of the slot and by avoiding vias a simpler mechanical structure for the circuit board production ( 5 . 6 ) pretend.

As the board material, a low cost high frequency material (Rogers RO4000 series) was selected. The stratification is constructed in such a way that a direct multilayer structure (see 7 . 8th ) as is possible with standard printed circuit boards. There are no unusual materials or manufacturing process with elaborate spacers and air dielectrics needed. In 6 the ladder structures of the respective level are shown.

By Optimizing the geometry of patch, slot, and feedline the desired effect is achieved.

In a theoretically optimal antenna system, the antenna elements must 10 be arranged at a distance of less than 0.5 wavelengths and to each antenna elements 10 Phase shifter can be assigned.

This leads to very high numbers of components and thus high final prices. It is now necessary the number of necessary Reduce control components. This can be done by sub-array formation respectively. However, this sub-array formation must conform to certain laws done so that the desired effect can be achieved.

at the sub-array formation increases the distance between the phase-controlled antennas to values significantly larger as 0.5 wavelengths. This leads to so-called Grating praise. Grating praises are additional main clubs in spatial directions differ from the orientation of the desired Main lobe differ.

3.2 sub-array formation by controlled Combination of 4 individual radiation elements

By symmetrical feeding (0 ° / 180 °) of the opposing feed points can be the gain of the grouped antenna element 10 be increased at low signal incidence angles and the Kreuzpolarisationsentkopplung be improved.

The Microstrip patch steel elements, which are oriented in diamond shape are for the respective polarization only at one Page fed. This leads to a slight asymmetry of the resulting radiation pattern and expresses especially at low angles of incidence of the signal wave. In one direction, there is a reduction in profit (-1 dBi) in the opposite direction to an increase (+1 dBi).

By the in 10 . 11 shown arrangement and the symmetrical feed required thereby, this effect is compensated and exploited in a positive way. (Opening angle +/- 70 °). Each opposite feed points are fed with 180 ° phase shift. The necessary phase shift of 180 ° can be achieved either by installation of a delay line (DL) as in 10 shown done. Or see through rotation of the feed line under the coupling slot by 180 ° 11 ,

By the symmetrical feeding will also be disturbing Components of each cross-polar field compensated and the Polarization decoupling significantly improved (from about 15 dB to 25 dB).

3.3 Coarse adjustment of the azimuth direction (90 ° steps) through controlled sub-array formation

In order to reduce the number of required phase shifter elements are each 4 Einzelelemen te to a subarray. This happens separately for each polarization (H-POL or V-POL). For the summary of the individual elements an electronically configurable summing network, which in ( 16 . 17 ) is used.

The Signal outputs of the radiation elements are each about two ¼ wavelength cables with one PIN diode, which is operated as a switch connected. signal output A with TL1 and TL4, signal output B with TL2 and TL6, signal output C with TL5 and TL3, signal output D with TL4 and TL7.

All in all created by this arrangement, a closed conductor structure. Two opposite PIN diodes D1 and D2 as well D3 and D4 are installed similarly polarized. In the orthogonal plane these are inverted polarized (D1 and D2 opposite D3 and D4). By this arrangement, by applying a control signal of +10 mA or -10 mA the PIN diodes alternately in a conductive (corresponding to a short circuit) or in a blocking state (corresponding to a high-impedance State).

Case 1:

The Control signal AZSW is set to +10 mA. This causes the PIN Diodes D1 and D2 in the conductive state corresponding to a low-resistance Impedance (ideal short circuit, 0 ohm) switched. The diodes D3 and D4 lock and represent a high impedance, which by the line characteristics of TL4, TL5 as well as TL6 and TL7 not affected. Through the ¼ wavelength long pipe sections TL1 and TL2, this short circuit is in an idle state transformed at point A and B. The same is done by transformation short circuit through D2 over TL3 and TL4 at point C and D.

Of the Short to D1 will be over the ¼ wavelengths long line TL10 also transformed into a Leelauf at the summation point S1. Thus, TL4, TL5 and TL8 form a summing structure which the Sum of the input signals from A and C to S1 gives.

Of the Short to D2 will be over the ¼ wavelengths long line TL11 also transformed into a Leelauf at the summing point S2. Thus, TL6, TL7 and TL9 form a summing structure which the Sum of the input signals from B and D to S2 gives.

Case 2:

The Control signal AZSW is set to -10 mA. Thereby are the PIN diodes D3 and D4 in the conductive state according to a low impedance (ideally shorted, 0 ohms). The diodes D1 and D2 block and provide a high impedance which is due to the line characteristics of TL1, TL2 and TL3 and TL4 not affected. By the ¼ wavelengths long line pieces TL4 and TL5, this short circuit in an idle state at points A and C transformed. The same happens by transformation of the short circuit by D4 via TL6 and TL7 at points D and B.

Of the Short to D3 will be over the ¼ wavelengths long line TL8 also transformed into a Leelauf at the summation point S1. Thus, TL1, TL2 and TL10 form a summing structure which the Sum of the input signals from A and B to S1 gives.

Of the Short to D4 will be over the ¼ wavelengths long line TL9 also transformed into an empty run at the summing point S2. Thus, TL3, TL4 and TL11 form a summing structure which the Sum of the input signals from C and D to S2 gives.

At the summing points S1 and S2 are now partial sums of two opposite antenna elements 10 in front.

Around a changeover to the four azimuthal sectors of 90 ° opening angle it is necessary to enable the partial sums at S1 and S2 with a switchable phase weighting to add. For this purpose is the control signal ASZWPH is used. A sum signal output is with a fixed phase shift of 120 ° applied, while the other with a switchable between 0 ° and 240 ° Phase shift is applied. Together with those by the Control signal AZSW possible states arise now four settings for the coarse alignment the radiation pattern of the sub-array.

These Arrangement is implemented separately for each polarization H and V.

In the 21 the switching states are shown as a function of the values of the control values AZSW and AZSWPH with the associated radiation diagrams in the azimuth plane.

3.4 Polarization control

The possibility of selecting and tracking the polarization is achieved by using an antenna element 10 with coupling points for horizontal and vertical polarization and high cross-polarization decoupling (> 25 dB).

The output signals of the function blocks AZ_SUM_V and AZ_SUM_H represent an orthogonal set of input signals. Together with the biphasic attenuators BiA1 and BiA2 and a subsequent summation stage SUM, a vector modulator structure is realized ( 20 ).

By varying the control signals POL_CTRL_H and POL_CTRL_V, the attenuation in the respective branches can be changed. The two-phase attenuators are realized by Lange couplers in thin-film technology and two PIN diodes. By changing the current flow through the diodes, the diode resistance can be changed. This makes it possible to change the attenuation between low and maximum and to change the phase between 0 ° and 180 ° ( 21 ).

3.5 Control of phase adjustment

The output signal of the polarization control unit is supplied to a phase control unit. The phase control unit is made up of a low-noise amplifier LNA5, the 90 ° hybrid, the two biphasic attenuators BiA3 and BiA4 and the summing stage SUM2. The aforementioned components without the LNA5 form a vector modulator for controlling the phase of the received signal of the sub-array. The DC control signals PHA_CTRL_I and PHA_CTRL_Q can be used to change the phase between 0 ° and 360 °. The LNA5 compensates for the losses in the phase shifter. ( 22 )

3.6 Integration of signal processing electronics into a signal processing element (SPE)

To support the concept of the modular design of the antenna system, the electronic components are implemented in integrated technology ( 23 . 24 ). For this purpose, multilayer structures are used.

3.7 Combination of sub-arrays to modules

Each module is made up of 16 sub-arrays arranged in a 4 × 4 matrix ( 25 . 26 ). The output signals of the sub-arrays of a module are summed on the module to form a signal. For this purpose, partial sums of adjacent sub-arrays are first formed. With regard to the cable routing, it should be noted that all cable lengths from the output signal of the sub-array to the central summation point of the module are the same length. In 27 this fact is shown graphically.

3.8 Combination of the modules to the antenna system

Around to support a modular / scalable structure the entire antenna array is divided into so-called antenna modules. These antenna modules are fully functional in themselves Antennas.

ever as required for the gain of the antenna or the shape of the directional diagram can be more or less of these modules be combined. The output signals of the antenna modules are then over so-called row or column summation circuits.

These Row or column summing circuits are in the form of a bus structure and also includes the preparation of the control signals.

By the chosen design ensures that the signal paths from each module to the central summation point of the entire antenna are long.

In 29 this concept is shown graphically.

3.9 Functional description of the TrackSat ^TM antenna system

The TrackSat ^TM antenna system is used to receive broadband satellite signals in Ku band (10.7 GHz - 12.75 GHz). The system can be operated with geostationary Medium Earth Orbit (MEO) or Low Earth Orbit (LEO) satellites. An adaptation to the various application scenarios is supported by the scalable system concept.

The TrackSat ^TM antenna system is designed to handle the frequency band to be received from 10.7 GHz - 12.75 GHz, corresponding to a bandwidth of 2.05 GHz, and in two selectable intermediate frequency bands from 0.95 GHz to 1.95 GHz, as well as 1.1 GHz to 2.15 GHz at the high frequency signal output in a signal level range, which allows the connection of commercial satellite signal receiver is available.

The antenna element 10 represents the fundamental interface to the electromagnetic wave impinging on the antenna surface from the satellite. This antenna element 10 converts the radiation-bound energy into a line-bound energy, which can be used for further signal processing. The antenna element 10 is designed so that the entire frequency band (10.7 GHz-12.75 GHz) can be processed. The antenna element 10 generates two orthogonally polarized signals associated with the horizontally and vertically polarized incident signal, respectively. The reception of both orthogonal polarizations is necessary to compensate for the change in relative polarization axes between the fixed transmitter (satellite) and the moving receiver (vehicle). This is done in the polarization control unit. The operation of the polarization control unit is in 20 described.

In order to minimize the number of signal processing components in the antenna system, the concept of sub-array has become 8th Education applied. Each 4 antenna elements 10 become a sub-array 8th grouped. The geometric arrangement is chosen so that by controlled summation of the separately available polarization from output signals, a coarse alignment of the directional pattern of the antenna in azimuth direction can be done. This allows stepwise alignment in four sectors covering an opening angle of 90 ° each.

The type of summary and the control are in 9 . 10 and 11 shown. If the azimuth range is divided into sectors + 315 ° to + 45 °, + 45 ° to + 135 °, +135 to + 225 ° and + 225 ° to + 315 °, the following settings result.

In order to control the directional diagram of the sub-array in the sectors + 45 ° to + 135 ° and + 225 ° to + 315 °, the signals from the two respectively adjacent antenna elements are separated by polarization 10 summed. This results in two sum signals for each polarization: partial sum 1 between antenna element 10A and antenna element 10B and partial sum 2 between antenna element 10C and antenna element 10D ,

In order to control the directional diagram of the sub-array in the sectors + 315 ° to + 45 ° and +135 to + 225 °, the signals from the two superimposed antenna elements are separated according to polarization 10 summed. This results in two sum signals for each polarization: partial sum 1 between antenna element 10A and antenna element 10C and partial sum 2 between antenna element 10B and antenna element 10D ,

The Output signals of these summation stages are each a low-noise Pre-amplifier supplied and amplified.

Around the directional diagram of the sub-array in the sector + 45 ° to + 135 ° and + 225 ° to + 315 ° the previously formed partial sums 1 and 2 separated by polarization summed by switching a relative phase shift of + 120 ° or -120 °. A phase shift of + 120 ° between subtotal 1 and 2 pivots the directional diagram in the sector + 45 ° to + 135 °. A phase shift of + 120 ° between Subtotal 1 and 2 pans the directional diagram into sector + 225 ° to + 315 °.

In order to control the directional diagram of the sub-array in the sector + 315 ° to + 45 ° and +135 to + 225 °, the previously formed partial sums 1 and 2 are separated according to polarization by switching a relative phase shift of + 120 ° or 120 ° summed. A phase shift of + 120 ° between subtotals 1 and 2 pivots the directional diagram in the sector +135 to + 225 °. A phase shift of + 120 ° between subtotals 1 and 2 the directional diagram pivots into the sector + 315 ° to + 45 °.

To this signal processing stage are two orthogonal through the Directional diagram of the sub-array weighted signals available. These signals are now supplied to the polarization tracking circuit. The orthogonal input signals, two biphasic attenuators and a final summing stage form a vector modulator. By different weighting of the two orthogonal signal components the polarization vector can be rotated by 360 °.

To This signal processing stage is only one of the selected Polarization corresponding signal for further processing to disposal.

In this signal processing level, the actual control and tracking of the antenna pattern takes place. The from the four antenna elements 10 formed sub-arrays 8th can be seen as new antennas with a roughly switchable directional diagram. The output signals of these new antennas are now provided with a phase weighting and summed up by rows and columns.

Each sub-array 8th is an in 22 Phase shifter switched on vector modulator basis. By means of control currents, which are generated by associated D / A converter, the respectively necessary phase adjustment is made.

RD:

Richtdiagramm

M:

Anzahl der Sub-Arrays in X-Richtung

N:

Anzahl der Sub-Arrays in Y-Richtung

a_m,n:

Amplitudengewichtung der einzelnen Antennen

k₀:

Wellenzahl 2π/λ

λ:

Wellenlänge

d_x:

relativer Abstand der Antennen in X-Richtung

d_y:

relativer Abstand der Antennen in Y-Richtung

u:

sin(θ)cos(ϕ)

v:

sin(θ)sin(ϕ)

u₀:

sin(θ₀)cos(ϕ₀)

v₀:

sin(θ₀)sin(ϕ₀)

θ:

variabler Elevationswinkel

ϕ:

variabler Azimutwinkel

θ₀:

Einfallswinkel Elevation

ϕ₀:

Einfallswinkel Azimut

The phase settings are calculated according to the following formula:

RD:

directivity pattern

M:

Number of sub-arrays in the X direction

N:

Number of subarrays in Y direction

a _{m, n} :

Amplitude weighting of the individual antennas

k ₀ :

Wave number 2π / λ

λ:

wavelength

_dx :

relative distance of the antennas in the X direction

_dy :

relative distance of the antennas in the Y direction

u:

sin (θ) cos (φ)

v:

sin (θ) sin (φ)

u ₀ :

sin (θ ₀ ) cos (φ ₀ )

v ₀ :

sin (θ ₀ ) sin (φ ₀ )

θ:

variable elevation angle

φ:

variable azimuth angle

θ ₀ :

Incidence angle elevation

φ ₀ :

Angle of incidence azimuth

To enable a modular, scalable structure, there are several sub-arrays 8th with the associated electronic signal processing elements (SPE) 9 summarized to so-called antenna modules. These modules consist of 16 sub-arrays arranged in a 4 × 4 matrix 8th with a respective grid spacing of 22.5 mm in the X and Y directions. The distance between the sub-arrays 8th was chosen so that the grating lobes occurring when the directional diagram is tilted fall within a range determined by the default directional diagram of the sub-array 8th is suppressed against the direction of the main lobe. By summing the phase-weighted output signals of the 16 sub-arrays, the output signal of the antenna module is produced. Each antenna module represents a fully functional antenna. This allows an application-specific adaptation to different requirements with regard to the gain and shape of the directional diagram.

For the application as a receiving antenna for mobile satellite signal reception in the Ku band is due to the requirements of winning the antenna system the combination of 16 antenna modules necessary. These 16 antenna modules are arranged in a 4 × 4 matrix. The distance of the modules in the X- and Y-direction among each other results from the necessary Size of the antenna modules and is 90 mm.

The output signals of the modules are first line by line (ROW_PCB) 5 summed, wherein the length of the connecting lines is designed so that the electrical transit time for all output signals of Mo dule is equal to the central transfer point of the row summation circuit.

Hereinafter, the output signals of the row summation circuit are calculated by means of a column summing circuit (COL_PCB). 6 is summed to an output signal of the antenna system, wherein the length of the connection lines is designed so that the electrical running time is the same for all output signals of the row summing circuits to the central transfer point of the column summing circuit.

The output of the column summing circuit then becomes a frequency translation assembly 15 and optionally converted to the frequency bands 0.95 GHz to 1.95 GHz and 1.1 GHz to 2.15 GHz

Around the directional diagram of the antenna in the desired direction to control and in the case of movement of the host vehicle to allow a tracking of the alignment An electronic tracking system is required. in principle can be a tracking of the orientation of the directional diagram by evaluation of sum and difference diagrams (Monopuls Tracking) respectively. However, this will be a not inconsiderable additional Hardware required.

Around To avoid this expense for the described antenna system an alternative method applied.

Through dynamic sensors 13 the orientation and the change of the orientation of the antenna platform is determined. From this information, the orientation of the antenna diagram can be adjusted in static as well as in dynamic applications.

The dynamic sensor system consists of a two-dimensional measuring Tilt sensor and a gyroscope which rotates around the Vertical axis of the antenna determined.

With the dynamic sensors, only a relative determination of the orientation of the antenna platform is possible. For the control of the directional diagram in the direction of the satellite to be received but an absolute determination of the alignment is necessary. This is done by coupling the sensor information with position data from a satellite navigation receiver 12 realized.

to Verification of the orientation is the signal power in the receive path measured. This must be within a specified tolerance window lie. If this is not the case will be an optimization method for alignment of the diagram.

4 Achieved benefits:

Large signal bandwidth

By the rhombic structure, the stratification, adaptation of the Slot feeding results in comparison to standard antenna arrangements increased bandwidth with respect to the course of Input impedance and the polarization behavior.

Large opening angle of the directional characteristic of the antenna element 10

The size, the diamond-shaped design, the vertical distance and the selection of the dielectric material results in an extended opening angle of the directional characteristic of the antenna element 10 (Extension about 40%).

Selection and tracking of the polarization

By Integration of two-phase attenuators becomes one electronic selection or tracking of the polarization the receiving antenna allows.

Optimized profit (S / N) at large swivel angles

By the arrangement of the antenna elements 10 In the sub-array, the symmetrical feeding as well as the directional summation in the azimuth direction results in a relation to a standard solution increased gain in terms of flat angle of incidence of the signal wave.

Modular construction

The Division into the sub-arrays, the serial interconnection and enable the use of the integrated electronic module a scalable structure of the overall system. The antenna size and therefore the reception characteristics can be increased by adding or removal of module units to the respective needs be adjusted.

Reduction of required components

By Application of the concept of sub-array formation can be a reduction the required phase shifter components by the factor 4 (example: instead of 1024 only 256 components).

Simple production

The Manufacturing can be done through standardized processes of PCB manufacturing respectively. The required electronic components are equipped and contacted in SMD technology.

5 application examples:

The The invention described above can be applied as follows.

5.1 Mobile reception of television satellite signals (DVB-S)

In 30 the concept for using the TrackSat ^TM antenna system for DVB-S mobile TV signal reception is shown.

5.2 Mobile reception of satellite signals for broadband internet access

In 31 is the concept of using the TrackSat ^TM antenna system for mobile broadband Internet access via satellite. Web content can be loaded onto the user PC via the described antenna system. The return channel for data requests by the user must be made available via an external communication system (eg mobile phone).

1

TrackSat ^TM antenna system

2

antenna

3

casing

4

antenna module

5

ROW_PCB, Zeilensummierschaltung

6

COL_PCB, Spaltensummierschaltung

7

mounting frame

8th

Sub-array, consists of antenna elements 10A , B, C, D

9

signal Processing Element (SPE)

10

antenna element (AE)

11

control computer

12

satellite navigation receiver

13

dynamic sensors

14

external interface

15

HF signal conversion

16

HF signal output

17

satellite RF signal

18

external commands

19

External monitoring

A, B, C, D

antenna elements 10 a sub-array 8th

AE

antenna element 10

A _S

radiation direction

AZ_SEL H

Azimuth Selection of the sub-array 8th : horizontal polarization

AZ_SEL V

Azimuth Selection of the sub-array 8th : vertical polarization

AZ_SUM H

Azimuth summation of the sub-array 8th : horizontal polarization

AZ_SUM V

Azimuth summation of the sub-array 8th : vertical polarization

BiA

Biphase Attenuator, two-phase attenuator

DC CTRL AZSW_H

Control signal for selecting the signal outputs of the antenna element to be summed 10 for horizontal polarization

DC CTRL AZSW_V

Control signal for selecting the signal outputs of the antenna element to be summed 10 for vertical polarization

DC CTRL AZSWPH_H

Control signal for coarse adjustment of the azimuth angle of the sub-array 8th for horizontal polarization

DC CTRL AZSWPH_V

Control signal for coarse adjustment of the azimuth angle of the sub-array 8th for vertical polarization

DL

delay Line, delay line

H

horizontal polarization

LNA

low Noise Amplifier, low-noise amplifier

PH_CTRL_I

control signal for in-phase component

PH_CTRL_Q

control signal for orthogonal component

POL_CTRL_H

Control signal of the sub-array 8th for horizontal polarization

POL_CTRL_V

Control signal of the sub-array 8th for vertical polarization

SPE

signal Processing element, signal processing element

SUM

signal adder

V

vertical polarization

VIA drill

via

QUOTES INCLUDE IN THE DESCRIPTION

This list The documents listed by the applicant have been automated generated and is solely for better information recorded by the reader. The list is not part of the German Patent or utility model application. The DPMA takes over no liability for any errors or omissions.

Cited patent literature

• EP 1146592 A1 [0002]
• EP 1202387 B1 [0005]
• - WO 2004/045020 A1 [0005, 0007, 0007]
• US 493164 S [0005]
• WO 002004079861 A1 [0005]
• WO 2005/067098 A1 [0006, 0006]
• US 5835057 A [0006]
• US 005835057 A [0006]
• WO 2005/004284 A1 [0007, 0007]
• WO 2004/079861 A1 [0008]

Cited non-patent literature

• Phased Array Antenna Handbook, Artech House 1994, ISBN 0-89006-502-0 [0002]

Claims (20)

Antenna system ( 1 ), comprising: a) a plurality of antenna modules formed as a phased array structure and arranged in N rows and M columns ( 4 ), where N and M are each natural numbers 1, 2, 3, ..., b) each antenna module being composed of a multiplicity of sub-arrays ( 8th ), c) where a sub-array ( 8th ) of four antenna elements ( 10 , A, B, C, D), which are arranged on a common printed circuit board, and d) wherein each antenna element ( 10 , A, B, C, D) is formed as a microstrip patch antenna in sandwich construction, which is formed of two spaced apart by an insulating layer, mutually parallel square metal layers (Layer 1, Patch 1, Layer 2 Patch 2), wherein the Edge length in the emission direction (A _S ) of the antenna system ( 1 ) is greater than that of the underlying lower square metal layer (Layer 2 Patch 2), which in each case two mutually perpendicular coupling slots (Layer 3) of two mutually perpendicular underlying feed lines (Layer 4) e) wherein the first feed line, the first feed signal (V11, V21, V12, V22) for a first polarization direction and the second feed line, the second feed signal (H11, H21, H12, H22) rotated by 90 ° to the first polarization direction Polarization direction whose respective RF feed signal in turn from one for a sub-array ( 8th ) common signal processing circuit ( 9 , SPE, layer 6) is generated with correct phase, amplitude and polarization, f) and a control computer ( 11 ) for each antenna module ( 4 ) calculates the necessary control signals in rows and columns, the control signals being transmitted via a first distributor ( 6 ) line by line via a second distributor downstream of each line (line_1 ... line_N) ( 5 ), each of the column-wise connected M antenna modules ( 4 ), g) the control computer ( 11 ) for a given emission direction A _S the control signals required for azimuth and elevation via the antenna modules ( 4 ) to the sub-arrays ( 8th ), whereby by amplitude, phase, and polarization-correct summation of each sub-array ( 8th ) generated in the radiation direction A _S total RF signal ( 17 ) is produced. Antenna system according to claim 1, characterized in that the plurality of subarrays ( 8th ) are arranged on a common printed circuit board, preferably on the common printed circuit board of the four antenna elements ( 10 , A, B, C, D) are arranged. Antenna system according to claim 1 or 2, characterized in that the plurality of antenna modules ( 4 ) are arranged on a common plane. Antenna system according to claim 1, characterized in that the four antenna elements ( 10 ) on the common printed circuit board of the sub-array ( 8th ) are arranged such that the center of the upper square metal layers (Layer 1, Patch 1) lie on the vertices of a first square, wherein the edges of the upper square metal layers (Layer 1, Patch 1) each at 45 ° to the sides of this square are inclined. Antenna system according to Claims 1 and 4, characterized in that the four antenna elements ( 10 ) on the common printed circuit board of the sub-array ( 8th ) are arranged such that the center of the lower square metal layers (Layer 2, Patch 2) lie on the vertices of a second square, wherein the edges of the lower square metal layers (Layer 2, Patch 2) in each case by 45 ° with respect to the sides of this square are inclined. Antenna system according to claim 1, 4 and 5, characterized characterized in that the centers of the first square and second Square over each other. Antenna system according to claim 1 and 6, characterized in that the edge length of the radiation in the direction (A _S ) of the antenna system ( 1 ) is at least 4% larger than that of the underlying lower square metal layer (Layer 2, Patch 2). Antenna system according to claim 1 and 6, characterized in that the edge length of the radiation in the direction (A _S ) of the antenna system ( 1 4) is greater than that of the underlying lower square metal layer (Layer 2, Patch 2), the insulating layer having a thickness of approximately 608 μm. Antenna system according to claim 1, characterized in that the two mutually perpendicular coupling slots (layer 3) of a sub-array ( 8th ) are arranged on a common plane such that all the coupling slots come to lie on the edges of a third square, the associated feed lines being arranged in matrix form such that the four feed points V11, V21, V12 and V22 of the first feed lines are columnar and the four feed points the second feeders H11, H21, H12 and H22 are arranged in rows ( 10 ). Antenna system according to claim 1 and 9, characterized in that in each case the two adjacent first feed points V11 and V21 of the first feed line with 180 ° phase shift relative to the two opposite second feed points V12 and V22 of the first feed line are fed and the two adjacent first feed points H22 and H21 the second supply line with 180 ° phase shift relative to the two opposite second feed points H11 and H12 of the second feed line are fed ( 10 ). Antenna system according to claim 1 and 10, characterized in that at the first feed points V11 and V21 of the first feed line a delay line (DL) with 180 ° phase shift and to the first feed points H21 and H22 of the second feed line, a delay line (DL) with 180 ° phase shift is connected ( 10 ). Antenna system according to Claims 1 and 9, characterized in that the first feed points V12 and V22 of the first feed line are coupled rotated by 180 ° and the first feed points H21 and H22 of the second feed line are coupled rotated by 180 ° ( 11 ). Antenna system according to claim 1, characterized in that for each polarization direction (H and V) a common signal processing circuit ( 9 , SPE, layer 6) is formed as a ring circuit, the matrix-like connected four signal inputs (H11, H21, H12 and H22, V11, V21, V12 and V22) and two signal outputs S1 and S2, wherein the centers of two adjacent signal inputs on the loop are connected by a first inner line, the center of which has the first signal output S1, the centers of two opposing adjacent signal inputs on the ring line being connected by a second inner line, the center of which has the second signal output S2, and wherein each center of adjacent signal inputs is connected to a diode (D1, D2, D3 and D4) connected to ground ( 12 . 13 ). Antenna system according to claim 1 and 13, characterized in that in the common signal processing circuit ( 9 , SPE, layer 6), the opposite diodes (D1 and D2, D3 and D4) are poled in pairs in the direction of the ring line or away from the ring line ( 12 . 13 ). Antenna system according to claim 1 and 14, characterized in that in the common signal processing circuit ( 9 , SPE, layer 6) for each polarization direction (H and V) for coarse driving of the four quadrants in the azimuth plane, an associated control signal (DC CTRL AZSW_H, DC CTRL AZSW_V) is fed to the loop and is switched between two opposite directions of current ( 12 . 13 ). Antenna system according to claim 1 and 15, characterized in that in the common signal processing circuit ( 9 , SPE, layer 6) for each polarization direction (H and V) for coarse driving of the four quadrants in the azimuth plane, the signal outputs S1 and S2 connected to one input of a summing element, wherein the signal from signal output S1 by +/- 120 ° relative to the Signal is delayed from signal output S2 by means of an associated control signal (DC CTRL AZSWPH_H; DC CTRL AZSWPH_V) ( 14 . 15 ). Use of the antenna system according to one of the claims 1 to 16 for receiving broadband satellite signals. Use of the antenna system according to one of the claims 1 to 16 for transmitting broadband satellite signals. Method for receiving broadband satellite signals by means of a mobile antenna system according to one of Claims 1 to 16, characterized by the following steps: a) Determining the direction of reception (A _S ) of the satellite signal by determining the direction vector between the antenna system ( 1 ) and satellite from the known position data of the satellite and by a z. B. operating according to the GPS principle satellite navigation receiver certain position of the antenna system ( 1 ), b) determining the adjustment of the coarse direction of the receiving direction (A _S ) in the azimuth plane by knowing the orientation of the antenna system with respect to the earth's surface and the directional vector between the antenna system ( 1 ) and satellite by generating the corresponding control signals by means of the control computer ( 11 c) determining the orientation of the polarization axis of the satellite RF signal to be received from the previously determined azimuth alignment; d) determining the fine alignment in the azimuth and elevation plane of the receive direction (A _S ) by calculating the adjustment variables of the phase shifters by evaluating the components of the direction vector between the antenna system ( 1 ) and satellite in azimuth and elevation direction, e) implementation ( 15 ) of the satellite RF signal into an intermediate frequency and output at the RF signal output ( 16 ). Method for receiving broadband satellite signals by means of a moving vehicle-mounted antenna system according to claim 1 to 16 and using the method according to claim 19, characterized by the following additional steps: f) determination of the proper motion of the antenna system ( 1 ) due to the vehicle movement by means of dynamic sensors and a satellite navigation receiver and g) tracking of the receiving direction (A _S ) to the respective satellite position according to the steps a) to e).