SE508958C2

SE508958C2 - Method and apparatus for calibrating a phase controlled array antenna

Info

Publication number: SE508958C2
Application number: SE9700826A
Authority: SE
Inventors: Bengt Inge Svensson; Hans Paul Israelsson; Per Olof Gustaf Malmborg; Rolf Lagerloef
Original assignee: Ericsson Telefon Ab L M
Priority date: 1997-03-07
Filing date: 1997-03-07
Publication date: 1998-11-16
Also published as: WO1998039818A1; SE9700826D0; SE9700826L; AU6644498A

Abstract

A phased array antenna (1) having separately controllable, regularly space antenna elements (2), the spacing (d) between the antenna elements (2) being such that the period of the array factor of the antenna (1) extends outside the visible region of the antenna (1), is calibrated in that the antenna elements (2) are controlled by a control unit (4) to produce an antenna pattern corresponding to a desired antenna pattern within predetermined limits at at least two different scan angles.

Description

h) Ut LJi lJn 508 958 IQ Ändamålet ernås även medelst anordningen enligt uppfinningen. som innefattar en styrenhet som är anordnad att kalibrera antennen vid minst två olika utstyrnings- vinklar. h) The object is also achieved by means of the device according to the invention. which comprises a control unit which is arranged to calibrate the antenna at at least two different control angles.

Genom att kalibrera antennen vid minst två olika utstyrningsvinklar blir det möjligt att nå de områden som behöver sidlobkorrigeras.By calibrating the antenna at at least two different equipment angles, it will be possible to reach the areas that need side lobe correction.

FIGURBESKRIVNING Uppfinningen kommer att beskrivas närmare nedan under hänvisning till bifogade ritning, på vilken fig. l schematiskt visar en uttöringsfornt av en fasstyrd gruppan- tenn enligt uppfinningen, tig. 2 är ett flödesschema över ett första förfarande enligt uppfinningen för kalibrering av antennen enligt fig. 1 och fig. 3 är ett flödesschema “över en andra utföringstbrin av förfarandet enligt uppfinningen.DESCRIPTION OF THE FIGURES The invention will be described in more detail below with reference to the accompanying drawing, in which Fig. 1 schematically shows an emission form of a phase-controlled group antenna according to the invention, fig. Fig. 2 is a flow chart of a first method according to the invention for calibrating the antenna according to Fig. 1 and Fig. 3 is a flow chart of a second embodiment of the method according to the invention.

FÖREDRAGNA UTFÖRINGSFORIVIER Fig. 1 visar schematiskt en utföringsform av en fasstyrd gruppantenn l enligt upp- tinningen. Vid den visade utföringsfomten innefattar antennen l på i och för sig känt sätt ett ﬂertal strålningselement 2. Det är underförstått att antennen såsom ett alternativ' likaväl kan bestå av ett antal delgrupper som var och en innefattar minst två strålningselement (icke visade). Varje strålningselement 2 (eller delgrupp) styrs individuellt medelst en sändar/mottagannodul (TRM) 3. TRívIerna 3 är anordnade att mottaga styrkommandon från en styrenhet 4. som är gemensam för samtliga TRMer 4.PREFERRED EMBODIMENT FORVIVES Fig. 1 schematically shows an embodiment of a phase-controlled group antenna 1 according to the thawing. In the embodiment shown, the antenna 1 comprises in a manner known per se a number of radiating elements 2. It is understood that the antenna as an alternative may as well consist of a number of subgroups, each of which comprises at least two radiating elements (not shown). Each radiating element 2 (or subgroup) is individually controlled by means of a transmitter / receiver module (TRM) 3. The TRVIs 3 are arranged to receive control commands from a control unit 4 which is common to all TRMs 4.

Antennen l år av den typ vid vilken avståndet d mellan strålningselementen 2 är < M2, varvid Ä är antennens l våglängd i vakuum.The antenna 1 is of the type at which the distance d between the radiating elements 2 is <M2, wherein Ä is the wavelength of the antenna 1 in vacuum.

Med ett avstånd d < M2 mellan strålningselementen 2 kommer det såsom ovan an- givits i beskrivningsinledningen fortfarande att ﬁnnas okalibrerade sidlober utanför l l\) Un Un 0 (J: b) 5 O 8 9 5 8 syntältet när antennen kalibreras vid en enda utstyrningsvinkel, vilka sidlober kom- mer att uppträda när antennen styrs ut.With a distance d <M2 between the radiating elements 2, as stated above in the description introduction, there will still be uncalibrated side lobes outside the l1 \) Un Un 0 (J: b) 5 0 8 8 5 5 8 when the antenna is calibrated at a single control angle, which side lobes will appear when the antenna is steered out.

En forsta uttöringsform av ett förfarande enligt uppfinningen for att kalibrera en fasstjvrd gruppantenn relativt ett önskat strålningsdiagram kommer att beskrivas un- der hänvisning till tlödesschemat i tig. 2. Antennen kan vara av i ﬁg. 1 visad typ el- ler av någon annan typ av fasstyrd gruppantenn. För enkelhets skull kommer tbrfa- randet att beskrivas i anslutning till den i tig. l visade antennen l.A first embodiment of a method according to the invention for calibrating a phase-controlled group antenna relative to a desired radiation diagram will be described with reference to the resolution diagram in FIG. 2. The antenna may be off i ﬁ g. 1 shown type or of any other type of phase controlled group antenna. For the sake of simplicity, the procedure will be described in connection with that in FIG. l showed the antenna l.

Det torde vara uppenbart för faekmannen att kalibreringar av antenner kan tittöras såväl i antennens sändningsmod som i antennens mottagningsmod. l själva verket kalibreras vissa antenner i såväl sändnings- som mottagningsmod med olika kriteri- CT.It should be obvious to the person skilled in the art that calibrations of antennas can be checked both in the mode of transmission of the antenna and in the mode of reception of the antenna. In fact, some antennas are calibrated in both transmission and reception modes with different criteria.

Det medelst tlödesschemat i tig. 2 illustrerade törfarandet innefattar ett antal steg 20-28.It by means of the tlöde schedule in tig. 2 illustrated the drying process comprises a number of steps 20-28.

I steg 20 ställs exciteringarna av strålningselementen 2 i tig. l in i motsvarighet till ett önskat strålningsdiagram.In step 20, the excitations of the radiating elements 2 are set in FIG. l into the equivalent of a desired radiation diagram.

I steg 21 ställs antennen 1 i tig. l in på en forsta önskad utstymingsvinkel, exem- pelvis O°.In step 21, the antenna 1 is set in fig. l at a first desired tuning angle, for example 0 °.

Vid den i steg 2l inställda utstyrningsvinkeln bestäms i steg 22 det strålningsdia- gram som åstadkommes medelst antennen 1 under kontroll av styrenheten 4 med gmndinställningar for amplitud och fas i TRMerna 3. l l\) UI 0 lJl 5 _ O U 9 5 8 4 l steg 23 kontrolleras huruvida skillnaderna mellan det i steg 22 bestämda strål- ningsdiagrammet och det önskade strålningsdiagrammet ligger inom förutbestämda gränser eller ej.At the control angle set in step 2l, the radiation diagram produced by the antenna 1 under control of the control unit 4 is determined in step 22 with basic settings for amplitude and phase in the TRMs 3. ll \) UI 0 lJl 5 _ OU 9 5 8 4 l step 23 it is checked whether the differences between the radiation diagram determined in step 22 and the desired radiation diagram are within predetermined limits or not.

Om svaret är ”nej” beräknas exciteringarna av strålningselementen 2 i steg 24 på i och for sig känt sätt utifrân det medelst antennen l âstadkomna strålningsdiagram- ITICI. l steg 25 beräknas skillnader mellan de i steg 24 beräknade exciteringarna av strål- ningselementen 2 och de i steg 20 i motsvarighet till det önskade strålningsdia- grammet inställda exciteringarna. l motsvarighet till de i steg 25 beräknade skillnadema alstras i steg 26 signaler for att korrigera styrningen av strålningselementen 2 till att alstra ett korrigerat strål- ningsdiagram i steg 22.If the answer is "no", the excitations of the radiating elements 2 in step 24 are calculated in a manner known per se from the radiating diagram ITICI produced by the antenna 1. In step 25, differences are calculated between the excitations of the radiation elements 2 calculated in step 24 and the excitations set in step 20 corresponding to the desired radiation diagram. Corresponding to the differences calculated in step 25, signals are generated in step 26 to correct the control of the radiation elements 2 to produce a corrected radiation diagram in step 22.

Denna slinga av steg upprepas tills svaret är "ja" i steg 23. dvs tills skillnaderna mellan det i steg 22 bestämda strålningsdiagrammet och det önskade strålningsdia- grammet ligger inom förutbestämda gränser.This loop of steps is repeated until the answer is "yes" in step 23. that is, until the differences between the radiation diagram determined in step 22 and the desired radiation diagram are within predetermined limits.

I enlighet med uppfinningen kontrolleras därefter i steg 27 huruvida antennen 1 ka- librerats vid en andra önskad utstyrningsvinkel eller ej.In accordance with the invention, it is then checked in step 27 whether the antenna 1 has been calibrated at a second desired control angle or not.

Vid föreliggande process är svaret ”nejï l steg 28 ställs därefter antennen 1 till en andra utstyrningsvinkel, exempelvis +30°, och steg 22-26 upprepas for denna andra utstymingsvinkel tills svaret är ”ja” i steg 23. Det är fördelaktigt att styra strålningselementen till att initialt åstadkomma l k) Un th 0 (Ju Lll 588 958 strälningsdiagrammet vid den andra utstyrningsvinkeln med de slutgiltiga TRM- inställningarna for den första utstyrningsvinkeln.In the present process, the answer is no. In step 28, the antenna 1 is then set to a second control angle, for example + 30 °, and steps 22-26 are repeated for this second tuning angle until the answer is "yes" in step 23. to initially produce the lk) Un th 0 (Ju Lll 588 958 radiation diagram at the second control angle with the final TRM settings for the first control angle.

I steg 27 kontrolleras ånyo huruvida antennen 1 kalibrerats vid en andra önskad ut- styrníngsvinkel eller ej.In step 27 it is again checked whether the antenna 1 has been calibrated at a second desired control angle or not.

Svaret är nu ”ja” och kalibreringsprocessen avslutas.The answer is now "yes" and the calibration process is completed.

Enligt uppfinningen kan bestämningen av strâlningsdiagrammet i steg 22 göras an- tingen genom direkt mätning på den plats i rymden där det önskade diagrammet är definierat eller genom mätning på ett annat ställe och en efterföljande transforme- ring till stället För det önskade mönstret. exempelvis närtälts/Üärrﬁiltstransformering och vice versa.According to the invention, the determination of the radiation diagram in step 22 can be made either by direct measurement at the place in space where the desired diagram is defined or by measurement at another place and a subsequent transformation to the place For the desired pattern. for example local tent / Üärr ﬁ oxygen transformation and vice versa.

Enligt en töredragen uttöringstorm mäts antennens tiärtältsdiagrani och det uppmät- ta närtältsdiagrammet transformeras till platsen För det önskade strálningsdiagram- met, exempelvis tjärrtältet. Därefter jämförs det till tjärrfältet transformerade när- filtsdiagrammet med det önskade fjärrfältsstrålningsdiagrammet.According to a dry drought storm, the aerial tent diagram of the antenna is measured and the measured near tent diagram is transformed to the location of the desired radiation diagram, for example the tar tent. Then the near-felt diagram transformed into the tar field is compared with the desired long-field radiation diagram.

Enligt uppfinningen kan på samma sätt beräkningarna av exciteringarna i steg 24 göras utgående från antingen direkt uppmätta strålningsdiagram eller de transforme- rade strålningsdiagrammen.According to the invention, the calculations of the excitations in step 24 can in the same way be made on the basis of either directly measured radiation diagrams or the transformed radiation diagrams.

Enligt en föredragen utföringsform mäts antennens närfältsdiagram, transfonneras det uppmätta närfaltsdiagrammet till platsen för det önskade strålningsdiagrammet, exempelvis tjärrfaltet, och transformeras det till tjärrfältet transformerade när- tältsdiagrammet från ﬁärrfältet tillbaka till strålningselementen. 1 l\) Vi U\ O 508 958 6 En andra uttöringsform av förfarandet enligt uppfinningen for att kalibrera en fas- styrd gruppantenn, exempelvis antennen 1 i tig. l, relativt ett önskat strålningsdia- gram kommer att beskrivas under hänvisning till ﬂödesschemat i tig. 3.According to a preferred embodiment, the near field diagram of the antenna is measured, the measured near field diagram is transposed to the location of the desired radiation diagram, for example the tar field, and the near field diagram transformed to the tar field is transformed from the scar field back to the radiation elements. A second embodiment of the method according to the invention for calibrating a phase-controlled group antenna, for example the antenna 1 in fig. 1, relative to a desired radiation diagram will be described with reference to the ﬂ fate diagram in fig. 3.

Flödesschemat i tig. 3 innefattar steg 20-36.The flow chart in fig. 3 includes steps 20-36.

I steg 30 inställes exciteringarna av strålningselementen 2 i motsvarighet till det önskade strålningsdiagrammet på samma sätt som i steg 20 i tig. 2. 1 steg 31 styrs strålningselementen 2 medelst styrenheten 4 i tig. 1 till att åstad- komma ett strâlningsdiagram med initiala TRM-inställningar av amplitud och fas vid en törsta och en andra utstyrningsvinkel. exempelvis +30° respektive -30°.In step 30, the excitations of the radiation elements 2 are set in correspondence with the desired radiation diagram in the same manner as in step 20 in FIG. In step 31, the radiation elements 2 are controlled by means of the control unit 4 in FIG. 1 to provide a radiation diagram with initial TRM settings of amplitude and phase at a thirst and a second control angle. for example + 30 ° and -30 ° respectively.

Dessa tvâ strâlningsdiagram alstrade vid den törsta respektive den andra utstyr- ningsvinkeln bestäms i steg 32* respektive steg 32”. 1 steg 33 kontrolleras huruvida skillnaderna mellan de i stegen 32' respektive 32” bestämda strålningsdiagrammen och det önskade strålningsdiagrammet ligger inom förutbestämda gränser eller ej.These two radiation diagrams generated at the thirst and the second equipment angle are determined in step 32 * and step 32 ”, respectively. In step 33, it is checked whether the differences between the radiation diagrams determined in steps 32 'and 32 ", respectively, and the desired radiation diagram are within predetermined limits or not.

Om svaret är ”ja” avslutas kalibreringsprocessen.If the answer is "yes", the calibration process ends.

Om svaret är ”nej” beräknas i stegen 34' och 34” å ena sidan exciteringarna av strålningselementen 2 för respektive utstymingsvinkel på i och tör sig känt sätt lik- som i steg 24 i tig. 2 utifrån de i stegen 32” och 32” bestämda strålningsdiagrammen och å andra sidan skillnaderna mellan de beräknade exciteringarna och de i steg 30 i motsvarighet till det önskade strålningsdiagrammet inställda exciteringarna liksom i steg 25 i tig. 2. Stegen 24 och 25 i tig. 2 har således kombinerats i stegen 34” och 34”1ﬁg.3. l0 7 598 958 I steg 35 kompileras de i stegen 34” och 34” beräknade excitationsskillnaderna på törutbestämt sätt. Det komplexa och eventuellt viktade medelvärdet av skillnaderna kan exempelvis bildas. l steg 36 omvandlas de i steg 35 kompilerade skillnaderna till korrigeringssignaler för att korrigera styrningen av strålningselement 2 till att alstra ett korrigerat strål- ningsdiagram i steg 31.If the answer is “no”, in steps 34 'and 34 ”, on the one hand, the excitations of the radiating elements 2 for the respective tuning angle are calculated in a manner known as in step 24 in FIG. 2 on the basis of the radiation diagrams determined in steps 32 ”and 32” and, on the other hand, the differences between the calculated excitations and the excitations set in step 30 corresponding to the desired radiation diagram as in step 25 in fig. Steps 24 and 25 in fig. 2 has thus been combined in steps 34 ”and 34” 1ﬁ g.3. l0 7 598 958 In step 35, the excitation differences calculated in steps 34 ”and 34” are compiled in a dry-determined manner. The complex and possibly weighted mean value of the differences can be formed, for example. In step 36, the differences compiled in step 35 are converted into correction signals to correct the control of radiation element 2 to produce a corrected radiation diagram in step 31.

Den av stegen 31 - 36 bestående slingan upprepas därefter För ett eller flera korrige- rade strâlningsdiagram tills det detekteras i steg 33 att skillnaderna mellan de i ste- gen 32' respektive 32” bestämda strålningsdiagraminen och det önskade strålnings- diagrammet ligger inom förutbestämda gränser.The loop consisting of steps 31 - 36 is then repeated. For one or more corrected radiation diagrams until it is detected in step 33 that the differences between the radiation diagrams determined in steps 32 'and 32', respectively, and the desired radiation diagram are within predetermined limits.

När svaret är "ja" i steg 33 avslutas enligt ovan kalibreringsprocessen.When the answer is "yes" in step 33, the calibration process is completed as above.

Enligt en tredje uttöringsform (icke visad) av kalibreringsfórfarandet enligt uppfin- ningen kombineras de i ﬁg. 2 och 3 illustrerade kalibreringstörfaranclena på i det följande beskrivet sätt.According to a third embodiment (not shown) of the calibration method according to the invention, they are combined in ﬁ g. 2 and 3 illustrated the calibration dryers in the manner described below.

När svaret är ”ja” på frågan i steg 23 i tig. 2 fortsätter kalibreringsprocessen med steg 31 i tig. 3 på medelst pilen i ﬁg. 2 antytt sätt i stället for att fortsätta med steg 27 1 ng. z.When the answer is "yes" to the question in step 23 in tig. 2, the calibration process continues with step 31 in FIG. 3 by means of the arrow in ﬁ g. 2 hinted instead of proceeding with step 27 1 ng. z.

Vid denna utforingsform av kalibreringstörfarandet enligt uppfinningen utförs såle- des kalibrering vid tre olika utstyrningsvinklar, exempelvis 0°, +30° och -30°.In this embodiment of the calibration method according to the invention, calibration is thus performed at three different equipment angles, for example 0 °, + 30 ° and -30 °.

Kalibrering av antennen vid minst två olika utstyrningsvinklar kommer att eliminera risken for att okalibrerade sidlober ”vandrar” in i strålningsdiagrarnmet när antennen styrs ut.Calibration of the antenna at at least two different equipment angles will eliminate the risk of uncalibrated side lobes "migrating" into the radiation diagram when the antenna is controlled.

Claims

UI IQ Ui 508 958 s PATENT REQUIREMENTS

1. l. Method for cooling a phase-controlled group antenna (l) with individually controllable. evenly distributed radiating elements (2), the distance (d) between the radiating elements (2) being such that the period of the array factor of the antenna (1) extends beyond the field of view of the antenna (1). characterized in that the radiation elements (2) are controlled to produce a radiation diagram corresponding to a desired radiation diagram within predetermined limits at at least two different equipment angles.

Method according to claim 1, characterized by steps a) controlling the radiation elements (2) to provide a radiation diagram at a first control angle. b) determining whether the differences between the radiation diagram produced in step a) and the desired radiation diagram are within said predetermined limits. c) if the differences between the radiation diagram produced in step a) and the desired radiation diagram are not within said predetermined limits, to calculate the excitations of the antenna elements (2) from the radiation diagram produced in step a), d) to calculate the differences between those in step c) the calculated excitations and excitations corresponding to the desired radiation diagram, e) that the differences calculated in step d) are fed as excitation corrections to control the radiation elements (2) to produce a corrected radiation diagram, t) that steps a) - e ) is repeated until the differences between the radiation diagram produced in step a) and the desired radiation diagram are within said predetermined limits, g) when the differences between the radiation diagram produced in step a) and the desired radiation diagram are within said predetermined limits. to control the radiation elements (2) to provide a radiation diagram at a second control angle and h) to repeat steps b) - t), i) to complete the calibration.

Method according to claim 2, characterized in that the radiation diagram at said second control angle in step g) is produced using the excitations of the radiating elements corresponding to the corrected radiating diagram corresponding to the desired radiation diagram within said predetermined limits.

Process according to claim 1, characterized by steps a) to control the radiation elements (2) to produce at least two radiation diagrams at different angles of control, b) to determine whether the differences between the respective radiation diagrams produced in step a) and the desired radiation diagram are within whether the differences between the respective radiation diagram generated in step a) and the desired radiation diagram are not within said predetermined limits, to calculate the excitations of the radiation elements (2) from the respective, in step a) radiation diagram, d) to calculate the difference between the excitations and excitations calculated in step c) and excitations corresponding to the desired radiation diagram, e) to compile the differences calculated in step d) for the respective radiation diagram, i) to feed them in step d) compiled the differences as excitation corrections to control the radiation elements (2) to provide resp. corrected radiation diagram, 10 lv Out 508 958 io g) to repeat steps b) - t) until the differences between the radiation diagram produced in step a) and the desired radiation diagram are within said predetermined limits. li) to complete the calibration.

Method according to claim 1, characterized by steps a) controlling the radiation elements (2) to produce a radiation diagram at a first control angle, b) determining whether the differences between the radiation diagram produced in step a) and the desired radiation diagram are within said predetermined limits or not. c) if the differences between the radiation diagram produced in step a) and the desired radiation diagram are not within said predetermined limits. to calculate the excitations of the radiation element (2) on the basis of the radiation diagram produced in step a). d) to calculate the differences between the excitations calculated in step c) and excitations corresponding to the desired radiation diagram. e) feeding the differences calculated in step d) as excitation corrections to control the radiation elements (2) to produce a corrective radiation diagram. t) repeating steps a) - e) until the differences between the radiation diagram produced in step a) and the desired radiation diagram are within said predetermined limits. g) when the differences between the radiation diagram produced in step a) and the desired radiation diagram are within said predetermined limits. controlling the radiation elements (2) to generate at least two radiation diagrams at tuning angles different from said first control angle. h) determining whether the differences between the respective radiation diagram produced in step g) and the desired radiation diagram are within said predetermined limits. * Ju 10 l \) Un (Ju 11 508 958 i) when the differences between the radiation diagram produced in step a) and the desired radiation diagram are within said predetermined limits, to control the radiation elements (2) to generate at least two radiation diagrams at control angles which differs from said first tuning angle. j) to determine whether the differences between the respective radiation diagram produced in step g) and the desired radiation diagram are within said predetermined limits, k) to compile the differences calculated in step) for the respective radiation diagram. l) feeding the differences compiled in step k) as excitation corrections to control the radiation element (2) to produce the respective corrected radiation diagram. m) repeating steps g - l) until the differences between the respective radiation diagram produced in step g) and the desired radiation diagram are within said predetermined limits. n) to end the calibration.

A method according to any one of claims 2-5, characterized in that the step of determining whether or not the differences between the radiation diagram produced and the desired radiation diagram are within said predetermined limits comprises the steps of measuring the antenna proximity diagram to transform the measured proximity diagram to the location the desired radiation diagram and to compare the transformed near-felt diagram with the desired radiation diagram.

A method according to any one of claims 2-5, characterized in that the step of calculating the excitations of the radiation elements from the generated radiation diagram comprises the steps of measuring the near field diagram of the antenna, transforming the measured near field diagram into the location of the desired radiation diagram and transforming the transformed radiation diagram. the near field diagram from the location of the desired radiation diagram back to the radiation elements. lx) Ut 508 958 12

Device for calibration of a phase-controlled group antenna (1) with individually controllable. evenly distributed radiation elements (2). wherein the distance (d) between the radiating elements (2) is such that the period of the array factor of the antenna (1) extends beyond the field of view of the antenna (1). characterized by a control unit (4) for controlling the radiation elements (2) to produce a radiation diagram corresponding to a desired radiation diagram within predetermined limits at at least two different control angles.

Device according to claim 8, characterized in that the control circuit (4) is arranged to perform the steps a) of controlling the radiation elements (2) to provide a radiation diagram at a first control angle. b) determining whether the differences between the radiation diagram produced in step a) and the desired radiation diagram are within said predetermined limits, c) if the differences between the radiation diagram produced in step a) and the desired radiation diagram are not within said predetermined limits. , to calculate the excitations of the antenna elements (2) on the basis of the radiation diagram produced in step a). d) to calculate the differences between the excitations and excitations calculated in step c) and excitations corresponding to the desired radiation diagram, e) that the differences calculated in step d) are fed as excitation corrections to control the radiation elements (2) to produce a corrected radiation diagram, f ) that steps a) - e) are repeated until the differences between the radiation diagram produced in step a) and the desired radiation diagram are within said predetermined limits, g) when the differences between the radiation diagram produced in step a) and the desired radiation diagram are within said predetermined limits, to control the radiation elements (2) to produce a radiation diagram at a second tuning angle and h) to repeat steps b) - t), i) to complete the calibration.

Device according to claim 9, characterized in that the control unit (4) is arranged to control the radiation elements (2) to produce the radiation diagram at said second tuning angle in step g) using the excitations corresponding to the corrected radiation diagram corresponding to said predetermined limits. the radiation diagram.

11. ll. Device according to claim 8, characterized in that the control unit (4) is arranged to perform the steps a) of controlling the radiation elements (2) to produce at least two radiation diagrams at different control angles. b) determining whether or not the differences between the respective radiation diagrams produced in step a) and the desired radiation diagram are within said predetermined limits, c) if the differences between the respective radiation diagrams generated in step a) and the desired radiation diagram are not within said predetermined limits. calculating the excitations of the radiation elements (2) from the respective radiation diagrams obtained in step a), d) calculating the difference between the excitations calculated in step c) and excitations corresponding to the desired radiation diagram, e) compiling the ) calculated the differences for each radiation diagram, f) to feed the differences compiled in step d) such as excitation corrections to control the radiation elements (2) to produce the respective corrected radiation diagrams, lk) UI Un 0 508 958 14 g) to repeat steps b) - t) until the differences between the respective radiation diagram produced in step a) and the desired radiation diagram are within said predetermined limits, h) to end the calibration.

Device according to claim 8, characterized in that the control unit (4) is arranged to perform the steps a) of controlling the radiation elements (2) to provide a radiation diagram at a first control angle. b) determining whether or not the differences between the radiation diagram produced in step a) and the desired radiation diagram are within said predetermined limits. c) if the differences between the radiation diagram produced in step a) and the desired radiation diagram are not within said predetermined limits, to calculate the excitations of the radiation elements (2) from the radiation diagram produced in step a). d) to calculate the differences between the excitations calculated in step c) and excitations corresponding to the desired radiation diagram, e) to feed the differences calculated in step d) as excitation corrections to control the radiation elements (2) to produce a corrected radiation diagram, t ) to repeat steps a) - e) until the differences between the radiation diagram produced in step a) and the desired radiation diagram are within the said predetermined limits, g) when the differences between the radiation diagram produced in step a) and the desired radiation diagram are within said predetermined limits, to control the radiation elements (2) to generate at least two radiation diagrams at control angles different from said first control angle, the radiation diagram produced and the desired radiation diagram are within said predetermined limits, i) when the differences between the radiation diagram produced in step a) and the desired radiation diagram are within said predetermined limits. controlling the radiation elements (2) to generate at least two radiation diagrams at control angles different from said first control angle. j) to determine whether the differences between the respective radiation diagram produced in step g) and the desired radiation diagram are within said predetermined limits, k) to compile the differences calculated in step) for the respective radiation diagram. 1) feeding the differences compiled in step k) as excitation corrections to control the radiation elements (2) to produce the respective corrected radiation diagrams, m) repeating steps g - l) until the differences between the radiation diagram produced in step g) and the the desired radiation diagram is within said predetermined limits, n) to end the calibration.

Device according to any one of claims 9-12. characterized in that the control unit (4) is arranged to perform the step of determining whether the differences between the produced radiation diagram and the desired radiation diagram are within said predetermined limits or not by measuring the near field diagram of the antenna, to transform the measured near field field diagram into the desired radiation diagram and to compare the transformed near-field diagram with the desired radiation diagram.

Device according to any one of claims 9-12, characterized in that the control unit (4) is arranged to perform the step of calculating the excitations of the radiation elements from the radiation diagram produced by measuring the near field diagram of the antenna, to transform the measured near field diagram into the desired the radiation diagram and to transform the transformed near field diagram from the location of the desired radiation diagram back to the radiation elements.