Abstract:
An improved antenna arrangement includes a reflector arrangement comprising a printed circuit board with an electrically conductive ground plane. The reflector arrangement also has a reflector frame with a coupling surface. The coupling surface is capacitively coupled to the ground plane. The coupling surface has a recess via which the ground plane, which is located underneath it, and/or the printed circuit board or an isolating intermediate layer which is provided above the ground plane or an isolating intermediate layer which is provided above the printed circuit board is exposed. The at least one antenna element arrangement is positioned and/or held on the printed circuit board in the area of the recess.

Description:
This application is the U.S. national phase of International Application No. PCT/EP2007/006638, filed 26 Jul. 2007, which designated the U.S. and claims priority to German Application No. 102006037518.1, filed 10 Aug. 2006, the entire contents of each of which are hereby incorporated by reference. 
     FIELD 
     The invention relates to an antenna arrangement, in particular for a mobile radio base station. 
     BACKGROUND AND SUMMARY 
     An antenna arrangement of this kind is known from EP 1 588 454 B1. This anticipatory document describes the use of, for example, an antenna arrangement, which can be vertically oriented, having a reflector. On the vertical lateral limiting lines of the reflectors two lateral webs are formed transversely, and in particular perpendicularly, to the reflector plane so as to protrude in the direction of radiation. The dual-polarized radiators arranged one above the other in the vertical direction sit between these lateral webs. According to this anticipatory document also, the base of the supporting mechanism and/or balancing means of the associated radiator assembly is capacitively connected (i.e. without electrical-galvanic contact) to the reflector or coupled thereto by connecting a cap in series. For this purpose, the reflector has a recess in which the non-conductive cap engages and is secured and in turn holds the supporting mechanism and/or balancing means or the base of the supporting mechanism and/or balancing means of the dual-polarized radiator. The internal conductor can be installed as is described in the above-mentioned prior art in this case. A flat antenna is known from DE 697 25 874 T2. It comprises a ground plane layer that is capacitively coupled to a base unit. A dielectric layer is provided between these two layers. 
     Antenna arrangements, in particular for a mobile radio base station, are also known for example from WO 00/039894 A1. This anticipatory document describes a reflector that can be vertical oriented. On the two vertical and mutually parallel outer, laterally located limits of the reflector, a lateral web is formed that protrudes in the direction of radiation and therefore transversely to the reflector plane. A plurality of dipolar arrangements consist of what are known as vector dipoles. They are provided radiating in two mutually perpendicularly oriented polarization planes one above the other in the vertical direction. In terms of construction, these vector dipoles are similar to dipole squares. Nevertheless, feeding takes place in such a way that despite the horizontally or vertically oriented dipoles, overall the dipole arrangement acts as an X-polarized antenna in which the two polarization planes that are perpendicular to each other are oriented at an angle of +45° or −45° with respect to the vertical or horizontal. 
     It can be gathered from WO 2005/060049 A1 that the dual-polarized radiators, which sit upstream of a reflector, may be provided with a capacitive outer conductor coupling. Axial holes that run perpendicular to the reflector plane are therefore introduced in each half of the two supporting mechanisms and/or balancing means that are rotated by 90° with respect to each other. Rod-shaped coupling elements  21  that are galvanically connected to the reflector project into these holes and are surrounded by cylindrical insulators onto which the pairs of supporting halves of the dual-polarized radiator assembly that are arranged rotated by 90° with respect to each other can be placed with the total of four axial holes. An internal conductor for feeding the two mutually perpendicular polarizations of the radiator assembly can be laid inside two rod-shaped coupling elements from the back of the reflector in each case. 
     Finally, antenna arrangements with reflectors are known on the longitudinal lateral regions of which, i.e. on the longitudinal or vertical lateral surfaces of which, longitudinal webs that protrude forwards from the reflector plane are provided, as may be gathered for example from the anticipatory documents WO 99/62138 A1, U.S. Pat. No. 5,710,569 A or EP 0 916 169 B1. 
     An alternative embodiment according to this anticipatory document discloses that instead of an electrically conductive reflector, conventionally in the form of a metal sheet, a printed circuit board may also be used on which the reflector is constructed. In this case, the electrically conductive ground plane is preferably omitted on one side of the printed circuit board or the cap is also provided with insulation in this region. 
     Finally, reference is made to WO 01/41256 A1 which describes a patch antenna. This patch antenna is arranged on a dielectric printed circuit board, which is provided with an electrically conductive layer on both sides. On the conductive dimension in the beam direction, a cross-shaped recess is provided, above which a radiator patch is arranged. 
     By contrast, the illustrative technology herein creates an improved dipolar shaped antenna arrangement which includes beam shaping possibilities and still has a simple construction. 
     The invention creates an improved antenna arrangement that can be easily and highly accurately produced with exactly predetermined radiation properties while avoiding potential sources of disruption such as undesirable intermodulations. 
     It has previously been conventional in the prior art to usually use reflectors made from a metal sheet. The radiator modules have been constructed on the reflectors. The longitudinal lateral limits have been in the form of longitudinal webs. These webs protrude transversely to the reflector plane. The webs can be constructed at a suitable location based on arranging the radiators between the reflector plane lateral external limit and the centrally arranged radiators. These longitudinal webs could be adjusted for example between a perpendicular orientation with respect to the reflector plane through to an angular orientation in such a way that desired beam shaping was possible. 
     If, by contrast, one wanted to use reflectors in the form of printed circuit boards (what are referred to as PCBs) which were provided on one side with an electrically conductive ground plane, then this required the webs needed for beam shaping to be connected to the ground plane of the printed circuit board by means of screw connections or soldered joints in order to achieve a definite galvanic connection at that point. In addition to being laborious, this assembly work caused potential intermodulation sources or disruption. 
     By contrast it is now proposed, starting from a printed circuit board which is preferably provided on its radiator side with an electrically conductive ground plane and a insulating layer located above it, to place a reflector frame thereon. The reflector plane is provided with a coupling surface parallel to the ground plane of the printed circuit board. The desired longitudinal and/or transverse webs that are required for diagram shaping in turn are constructed on this coupling surface. In other words, a capacitive reflector frame coupling is proposed, for a dipolar shaped radiator assembly (preferably a dual-polarized radiator assembly), that allows the longitudinal and/or transverse webs required for diagram shaping to be capacitively coupled to a ground plane sitting on a printed circuit board. 
     In a preferred embodiment, the reflector frame provided according to the invention can be made from an electrically conductive metal, for example aluminum. In particular, a reflector frame of this kind can be produced by way of all suitable production processes, for example by a casting process, by shaping, milling, etc. It is also possible to produce a reflector frame of this kind from an electrically non-conductive material, for example plastics material, which is coated with an electrically conductive layer. 
     In a particularly preferred embodiment, the reflector frame is produced from a punching, in particular from a metal sheet, by means of a punching/bending process. In the process it is possible by way of suitable punching and subsequent canting to produce an appropriate three-dimensionally shaped reflector frame from a metal sheet in which the lateral limits or webs are assembled from the metal sheet plane by canting and orientation transverse to the reflector plane. At the same time, mutually offset transverse webs can be provided in the add-on direction, whereby the individual radiators or radiator groups are delimited from each other. These transverse webs can also be assembled transversely, and in particular perpendicularly, to the reflector plane by punching and canting or bending. 
     In a particularly preferred embodiment tongues are formed on the outside of the thus formed transverse webs so as to project away from each other in the axial extension. The tongues can engage in corresponding slotted recesses in the longitudinal lateral limitations if the longitudinal lateral limit has also been assembled in corresponding transverse orientation to the reflector plane following the punching and canting process. 
     Capacitive coupling of the reflector frame on a printed circuit board without galvanic connection between reflector and printed circuit board ground plane is therefore provided. A stable intermodulation-free connection is provided. A clearly defined spacing and/or a clearly definable size of the coupling surfaces means that an exactly defined coupling between ground plane of the printed circuit board and the reflector frame may also primarily be ensured. 
     Finally quick and uncomplicated assembly is also possible, whereby sources of error are reduced and above all soldered joints are omitted on the reflector. 
     The completely assembled unit, comprising reflector frame and printed circuit board, forms a self-supporting unit. The reflector frame can be connected to the printed circuit board using any suitable means, for example by means of clips, a double-sided adhesive tape, separate adhesives, etc. 
     The ground plane on the printed circuit board is preferably originally provided with an insulating layer, for example in the form of paint, in particular a solder resist, a film or some other plastics material layer, which allows metallic isolation from the reflector frame. If the reflector frame is glued by means of a double-sided adhesive tape then this already provides an insulation and therewith metallic isolation between the electrically conductive reflector frame on the one hand and the ground frame on the printed circuit board on the other, so a separate insulating layer can even be omitted on the ground plane. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       Further advantages, details and features emerge from the following embodiments described with reference to figures, in which, in detail: 
         FIG. 1  shows a schematic three-dimensional illustration of a basic type of inventive antenna with a dual-polarized radiator assembly; 
         FIG. 2  shows an exploded view of the embodiment of  FIG. 1 ; 
         FIG. 3  shows a corresponding exploded view for an inventive antenna arrangement with three mutually offset and dual-polarized radiators; 
         FIG. 4  shows a further embodiment of an inventive reflector frame for, by way of example, eight radiator devices arranged mutually offset in the add-on direction; 
         FIG. 5  shows a metal sheet as the starting point for forming a reflector frame, disclosed with reference to  FIG. 4 , by illustrating the punching lines; 
         FIG. 6  shows an exploded view of the antenna arrangement for using the reflector frame described with reference to  FIGS. 4 and 5 ; 
         FIG. 7  shows a schematic cross-sectional view through a dual-polarized radiator with a portion of the reflector arrangement to illustrate feeding of the radiator; and 
         FIG. 8  shows an embodiment that has been modified with respect to  FIG. 7 . 
     
    
    
     DETAILED DESCRIPTION 
       FIG. 1  shows the basic type of inventive antenna arrangement as can be used for example for a mobile radio base station. The antenna arrangement comprises a reflector arrangement  1 , upstream of which a dual-polarized radiator or a dual-polarized radiator assembly  3  is provided. The illustrated embodiment involves a vector dipole which radiates in two mutually perpendicular polarization planes P that are perpendicular to the reflector plane and run more or less diagonally through the corners of the, in plan view, quadratically shaped radiator assembly. Reference is made by way of example to WO 00/039894 A1 with respect to the construction and mode of operation of a radiator of this type. 
     Basically however any radiator or radiator type can be used within the scope of the invention, in particular dipole radiators and/or patch radiators, as are known for example from anticipatory documents DE 197 22 742 A1, DE 196 27 015 A1, U.S. Pat. No. 5,710,569 A, WO 00/039894 A1 or DE 101 50 150 A1. 
     The dual-polarized radiator shown in  FIGS. 1 and 2  each comprise two pairs of radiator halves  3   a  that are mutually offset by 90° and are each held by a supporting mechanism and/or balancing means  21  located underneath. In terms of principle the supporting mechanism and/or balancing means  21  is two supporting mechanisms and/or balancing means that are mutually offset by 90° (namely for each polarization), for which purpose downwardly extending slots  21   b  that separate the radiator halves  3   a  from each other are provided in the supporting mechanism  21  (the balancing means being part of this supporting mechanism). The slots end just before the base  21   a  located underneath which connects everything together. 
     As also emerges in particular from the exploded view in  FIG. 2 , the overall construction of the antenna arrangement is such that it comprises a printed circuit board  5 , namely what is referred to as a PCB, which is preferably provided on the side  5   a  that faces the radiator side, what is known as the radiator or ground plane side  5   a , with a preferably all-over electrically conductive ground plane  7 . The electrical components and the strip conductors that connect the electrical components are then provided on the opposing strip conductor plane  5   b  (i.e. on the underside of the printed circuit board  5  that is not shown in detail in  FIGS. 1 and 2 ). 
     The ground plane  7  is conventionally covered with an insulating layer  8 , which is indicated in  FIG. 2  only in the left-hand region, for example in the form of a plastics material or film layer, a paint layer, for example in the form of what is known as a solder resist layer, etc. 
     Building thereon an arrangement  11  that is separately reproduced in  FIG. 2  is disclosed which will hereinafter also be called the reflector frame  11 . This reflector frame  11  comprises a coupling surface  13  which when finally assembled runs parallel to the ground plane  7 . In the illustrated embodiment this coupling surface  13  is provided with longitudinal webs  15  and transverse webs  17  running perpendicular to the coupling surface  13 . In the illustrated embodiment these are formed and/or provided on the external limits of the reflector frame  11 . They may also be located offset and further in on the outer limits of the reflector frame  11 , so a portion of the reflector that protrudes externally over the webs  15 ,  17  remains. These longitudinal and transverse webs  15 ,  17  are also connected to each other at the corner regions  19 . The illustrated longitudinal or transverse webs do not have to be oriented perpendicular to the reflector surface  13 . These webs can to some extent also run in an orientation to the reflector surface that differs by an angle of 90°, for example so as to diverge or converge in the beam direction or can be inclined more to the left or right, etc. In principle there are no limitations in this respect. 
     The reflector frame  11  is preferably an electrically conductive material, for example a metal cast part (aluminum, although other materials can also be considered here). This can also be a plastics part which is then metalized, i.e. has been coated with a metallically conductive surface. In particular when producing the reflector frame  11  from metal other production processes may be considered, for example production of the reflector frame by deep-drawing, milling or the like. 
     From the illustration according to  FIGS. 1 and 2  it may also be seen that the coupling surface  13  is provided with a recess  13   a  which in the illustrated embodiment is so large in the longitudinal and transverse directions that the dual-polarized radiator  3  shown in  FIGS. 1 and 2  also passes through this recess  13   a  with its radiator elements  3   a.    
     To assemble the antenna arrangement the radiator assembly  3  is, for example, firstly mounted on the printed circuit board  5 , i.e. in particular mechanically fixed. For example, this can be done by fixing a screw that is to be screwed in from the back of the printed circuit board, or by other clip-like fastening elements. The supporting mechanism and/or balancing means  21 , via which the radiator elements  3   a  of the dual-polarized radiator  3  are held, are capacitively coupled to the ground plane  7  of the printed circuit board  5  located underneath. The reflector frame  11  can also be connected to the printed circuit board for example by the above-described or other suitable mechanical measures. 
     The printed circuit board  5 , i.e. the ground plane  7  provided thereon, is covered by means of an insulating layer  8  (for example in the form of a paint layer). A capacitive coupling is produced between the underside of the supporting mechanism and/or balancing means  21  (i.e. between the electrically conductive base  21   a  of the radiator assembly  3  and the ground plane  7 ) and between the electrically conductive coupling surface  13  and the ground plane  7 . A d.c. or galvanic connection of these parts is reliably avoided. In other words, the paint layer applied to the ground plane would be completely adequate as an insulator, so an additional insulating layer is not necessary to achieve the capacitive coupling. 
     However the reflector frame  11  is preferably fastened to the top of the printed circuit board  5  by means of double-sided adhesive film  9 . The adhesive film  9  is provided with a window-like cut-out  9 ′, the size and positioning of which matches or approximates the cut-out  13   a  in the coupling surface  13  of the reflector frame  11 . As the insulating layer  8  is conventionally always provided on the ground plane  7  in the form of a paint layer, this insulating layer is primarily used as corrosion protection for the ground plane which is often made of copper. The double-sided adhesive film can be glued to this insulating or paint layer  8 . In such a case the ground plane  7  need also not be provided with an insulating layer  8 . 
     The adhesive tape  9  can comprise said recess  9 ′. It is irrelevant for the electrical functions whether the radiator device in the form of what is referred to as a vector dipole is also likewise held by means of said adhesive tape  9  with respect to the ground plane  7  or printed circuit board  5 . The dipole is capacitively coupled (in this case via the lower base  21   a ) to the ground plane  7  employing the same principles as in relation to the reflector frame  11 , so the spacing may also vary to a certain extent (for example 0.5 mm). This being the case, the adhesive film  9  could also be formed so as to be continuous and without window  9 ′. This would have certain drawbacks in terms of internal conductor assembly for the radiator assembly  3 . For example, the internal conductor which is to be laid in the radiator device would have to be inserted through the adhesive tape  9 . This being the case, the window-like recess  9 ′ is preferably provided in the adhesive tape  9 . In the process, the radiator is mounted on the printed circuit board by separate fixing measures while maintaining the capacitive coupling. 
     If the insulating layer  8  on the ground plane  7  should also be provided with a window, the insulating layer  8  is omitted in the region of this window (it being possible for this region, where the insulating layer  8  is omitted on the ground plane, to comparably match the size and/or arrangement of the other window  9 ′ with respect to the double-sided adhesive device  9  and/or recess  13   a  in the coupling surface  13 ). The ground plane  7  would be “blank” in this region. In this case the base  21   a , i.e. the underside of the supporting mechanism and/or balancing means  21 , could also be galvanically connected to the ground plane  7 . Holes are formed in the printed circuit board and axial holes that align therewith are formed in the base  21   a  of the supporting mechanism and/or balancing means  21  of the radiator assemblies in order to upwardly guide a respective internal conductor. The respective internal conductor is used for feeding, from the back of the printed circuit board and to galvanically couple, or inductively couple, as described for example in WO 2005/060049. This can be done via a section of a bridge to the respective diagonally opposite second half  3   a  of the radiator device  3  located above. This being the case, reference is also made in this regard to the above anticipatory document with respect to the mode of operation. 
     Following the thus effected pre-assembly, the reflector frame  11  is then positioned from above, the radiator assembly  3  then being guided through the recess  13   a  in the coupling surface  13  and through the recess  9 ′ in the double-sided adhesive device  9 . 
     Any conceivable connecting methods may be considered to ensure a secure connection between the coupling surface  13 , i.e. a secure connection between the reflector frame  11  and the printed circuit board. Thus for example glue can be applied to the top of the printed circuit board (i.e. the ground plane or the insulating layer  8  that covers the ground plane) and/or to the underside of the coupling surface  13 . However clip-like parts that mesh when positioned and produce a latching are also possible. 
     The above-mentioned double-sided adhesive tape  9  is preferably used however, whereby a strictly predefined spacing between the coupling surface  13  and the ground plane  7  is ensured and a mechanically secure connection is produced at the same time. As a result of this type of connection the reflector frame  11  with the printed circuit board  5  constitutes a securely connected, self-supporting unit. 
     A capacitive coupling is ensured thereby which also ensures the desired capacitive connection of the ground plane for the longitudinal and/or transverse webs  15 ,  17 . 
     If the longitudinal and transverse webs  15 ,  17  are not securely connected to each other in their corner regions  19 , they can be bent toward or away from one another by different bending, in particular if the reflector frame is made from a metal sheet, whereby the radiation diagram of the antenna can be changed and/or adjusted to the desired extent. 
       FIG. 3  only reproduces an enlargement to the extent that the corresponding antenna arrangement can also comprise a plurality of radiator assemblies  3  that sit side by side or one above the other in the add-on direction. An antenna arrangement of this kind with a plurality of radiators is conventionally assembled in the vertical direction, so the plurality of radiator assemblies are arranged so as to be spaced apart one above the other in a vertical plane. The reflector frame can comprise a number of reflector fields  25  that matches the number of radiator arrangements. The size of the antenna arrangement can be enlarged as desired in this respect. In this case the double-sided adhesive tape  9  is preferably formed as a correspondingly elongated film which is provided with three recesses  9 ′ that match the three recesses or windows  13   a  in three thus formed reflector fields  25  of the reflector frame  11 . The hole  26  worked into the printed circuit boards means that, similar to in the embodiment according to  FIG. 3 , the respective radiator device can be fixed from below by screwing a screw into the base  21   a  of the supporting mechanism and/or balancing means  21  of the radiator device  13 . An electrically non-conductive screw is preferably used. The base of the supporting mechanism and/or balancing means of the radiator device  3  is thus capacitively coupled to the ground plane  7  of the printed circuit board  5 . 
     With reference to  FIGS. 4 to 6 , a reflector frame for eight radiator assemblies or radiator groups is disclosed. By way of example, if the antenna arrangement and therefore the reflector frame are assembled in the vertical direction, two continuous longitudinal webs  15  may extend in the vertical direction. In the case of a total of eight reflector fields  25 , this comprises nine transverse webs  17 . With reference to  FIGS. 4 to 6  it is also disclosed that this reflector frame  11  can be produced for example from a metal sheet, i.e. from a sheet material, by punching and canting or bending. 
     It can be seen from the plane developed view according to  FIG. 5  that it is not just one recess  13   a  that has been punched from the material. Rather, as a result of transverse and lateral punched sections  27 , the material of the transverse webs  17  is ultimately also punched out. 
     Following the effected punching process according to  FIG. 5 , the longitudinal and transverse webs located in one plane can preferably be inclined upwards by 90°. The transverse webs  17  along the canting lines  17   a  in each case are assembled at preferably 90° with respect to the plane of the coupling surfaces  13 . The two longitudinal webs  15  are assembled along the canting lines  15   a  at 90°. 
     As may also be seen from  FIGS. 4 to 6 , the punching process is performed such that a respective tongue  17   c  that protrudes from the transverse web  17  and into its plane is formed on the lateral edges  17   b  of the transverse webs  17 . A respective slotted recess  15   b  is punched out of the two lateral webs  15  at an appropriate position in the finally produced reflector frame. When the reflector frame is finally assembled, the tongues  17   c  of the transverse webs  17  engage in the slotted recesses  15   b  of the longitudinal webs  15 , as can be seen from  FIGS. 4 and 6 . The transverse webs  17  are also securely mechanically held and fixed in position thereby. 
     Otherwise, the thus formed reflector frame  11  is positioned in the described manner, optionally with separate insertion of an insulating layer or film  9  on the ground plane  7 , i.e. ultimately on the printed circuit board  5 , and is suitably fixed thereto, as described preferably with insertion of a double-sided adhesive tape  9 . 
     It is clear from the illustration that in this embodiment, the window-like recess  13   a  is not just square but, in contrast, is also larger. Once the transverse web  17  has been lifted up, a corresponding rectangular portion is removed from the coupling surface. This being the case, the recess  13   a  is T-shaped in this instance. Only in the illustration according to  FIG. 5  is the recess still square at the top right-hand edge, as in this embodiment the transverse web  27  located furthest right is tilted up via a bending edge  17   a  located, from its perspective, on the. In other words, no additional portion of material is removed from the coupling surface region here. 
     In contrast to  FIGS. 4 and 5 ,  FIG. 6  indicates only as a variation that the lateral portions of the coupling surface  13  can have different widths, depending on how wide the reflector arrangement formed by the ground plane should be in total. Finally, it is noted that by way of example the transverse webs  17  do not have to be provided with lateral edges  17   b  running at a right angle to the bending edge  17   a . Instead, the punch lines can also run obliquely here such that when assembled, the two longitudinally running webs are not oriented perpendicularly to the reflector plane but can be oriented so as to, for example, diverge (or converge) in the beam direction. For the sake of completeness, it is again emphasized that a respective recess  26  is provided in the printed circuit board in the centre of the radiator arrangement  3 . Via this recess, for example from the back of the printed circuit board  5 , a screw (in the case of capacitive coupling, a plastic screw) can be screwed into the base  21   a  of the supporting mechanism and/or balancing means  21  in order to mechanically fix the radiator arrangement  3 . Four size-reduced holes  31  are also apparent, via which an internal conductor for feeding the dual-polarized radiator arrangement can ultimately be supplied. 
       FIGS. 7 and 8  only indicate in a schematic section through a corresponding radiator arrangement how a dual-polarized or, in a similar manner, a mono-polarized radiator  3  can be fed. 
     Feeding conventionally takes place by means of a coaxial cable which runs from the underside of the reflector through an axial hole  103  leading in the supporting mechanism or balancing means  21  to the plane of the actual dipole and/or radiator halves  3   a . The coaxial cable is stripped at the upper end of this axial hole at the level of the dipole and/or radiator halves  3   a . In this way, the external conductor, which is insulated in the axial hole  103  from the supporting mechanism and/or balancing means  21 , is exposed. In the upper region, it is then electrically/galvanically connected for example by means of a soldering  201 , to the inner end of an associated dipole or radiator half  3   a . The drawings in  FIG. 5  show substantially only the internal conductor  101   b . The coaxial cable would therefore be laid from bottom to top through the axial hole  103 . The external conductor, as mentioned, then is electrically-galvanically connected at the upper end of the supporting mechanism  21  to the associated dipole or radiator half  3   a  via the soldering  201 . The external conductor is insulated from the supporting mechanism  21  up to this point. 
     Alternatively or preferably however, a coaxial feeder cable is connected in such a way that the external conductor is held at the lower end of the hole  103 , for example at a soldering point  201 ′. The internal conductor  101   b  is held only by an insulator and is separately upwardly guided in the hole  103 . The hole in the supporting mechanism therefore acts as an external conductor that surrounds the internal conductor  101   b  so a more or less coaxial feeder is formed hereby. The dipole and/or radiator halves, which as a rule are electrically-galvanically conductively connected to the supporting mechanism as a joint component, are fed by the coaxial feeder. 
     If one dipole half (which is not fed via the internal conductor) is not fed by an electrical-galvanic coupling, for example in the region of the hole in the supporting mechanism, but for example by soldering-on of an external conductor of a coaxial cable, appropriate feeding can also be brought about capacitively. This can be done for example by a capacitive coupling between the base of the supporting mechanism and the ground plane or reflector surface. Therefore the associated feeder, usually the external conductor of a coaxial cable, is conventionally connected in a region underneath the supporting mechanism. In plan view, this supporting mechanism is located perpendicularly to the reflector, preferably in the region underneath the dipole or radiator half that is fed thereby. 
     The internal conductor  101   b  which is conventionally connected to the internal conductor of a coaxial cable is usually bent substantially at the level of the dipole and/or radiator halves  3   a  by 90° or substantially 90°. The internal conductor leads to the adjacent inner end of the associated second dipole and/or radiator half  3   a  and is conventionally electrically connected there by means of soldering  203 . 
     In the case of a dual-polarized radiator, feeding of the dipole and/or radiator halves  3   a  that are mutually offset by 90° takes place accordingly. The second internal conductor, running so as to cross the first internal conductor  101   b , is arranged on a different plane so the two internal conductors do not touch in the middle but bypass each other. 
     In the case of a simply polarized radiator with just one polarization plane, only one feeder, which is also called an internal conductor, is required. 
     The embodiment according to  FIG. 8  shows that the end  101   b ′ of the internal conductor  101   b  ends freely in a further axial hole  103 . This further axial hole  103  is provided in the supporting and/or balancing mechanism  21 . In this case, the freely-ending end portion of the internal conductor  101   b  is guided downwards over a certain axial length in this further hole  103 . It is held in the hole  103  by an insulator  203  (similar to the corresponding insulator  203  for fixing the internal conductor  101   b  in the other axial hole  103 ), whereby a capacitive or serial coupling is effected here with respect to the second dipole and/or radiator half  3   a′.    
     Other types of feeding are also possible. 
     It is mentioned purely for the sake of completeness that it may also be seen from  FIGS. 7 and 8  for example that in this case the slots  123  extend up to the lower plane or base  121  of the supporting and/or balancing mechanism  21 . The height of this supporting and/or balancing mechanism  21  or the slots  123  should preferably be in a range from about ⅛ to ⅜ of a wavelength from the relevant operating frequency band that is to be transmitted or received. The height should therefore preferably be ⅛ to ⅜, based on the mean wavelength λ of the frequency band that is to be transmitted or received, i.e. preferably at about ¼λ. In general the radiator height with respect to the reflector, i.e. with respect to the ground plane or reflector surface, should therefore not fall below a value of λ/10, wherein, in principle, there is no upper limit, so the radiator height could even be any multiple of λ. The length of the slots  123  can then be adjusted accordingly.