DE10034911A1 - Antenna for multi-frequency operation - Google Patents

Abstract

An improved antenna with at least two individual radiators (1, 2) can be operated in at least two frequency bands (f1, f2, ..., fn). The antenna is improved by the following measures: DOLLAR A - each output of the individual radiators (1) which can be operated in at least two frequency bands (f1, f2, ..., fn) or the output of a group of corresponding individual radiators (1) is a crossover (21 ), whereby the frequency band present at the radiator-side connection is present separately in at least two sub-frequency bands (f1, f2, ..., fn) at the supply network-side connections (23.1, 23.2), DOLLAR A - a feed network (7) is set up so that the feed-side connections (23.1, 23.2) on the crossover (21) for the respective sub-frequency band for beam shaping and in particular for different setting of the lowering angle of the main lobe are connected together with a predefinable or changeable adjustable phase and / or amplitude.

Description

The invention relates to an antenna for a multfre quenzbetrieb according to the preamble of claim 1.

It is important for a network operator in the mobile communications sector tig, antennas for the different frequencies the same to be able to use early. However, since for the different Services also have different requirements on the supplier area or network planning are provided also different radiation characteristics, in particular different vertical drop angles for the vertical cha tactics required. Different verti would be ideal kale lowering angle for the main lobe for the different Frequencies. However, this is with the previously known Lö solutions for closely adjacent frequencies not possible.

Therefore, only solutions are known which are suitable for the different frequency ranges different radiators ver turn. For example, these can be nested  Dipoles consist of, for example, this DE-A1 198 23 749 for a dual polarized multib antenna can be seen. The disadvantage here is however, due to the geometry of the arrangement the frequency bands cannot be immediately adjacent NEN, but must have a ratio of 1: 2.

In addition, the publication "Electronic Letters ", August 1999, Vol. 35, No. 17, pp. 1399-1400, from Yeunjeong, Kim, Wansuk Yun and Youngjoong Yoon a dual Band patch antenna known which different An conclusions for two different frequencies. Here, however, are the connections for each other Frequency polarized orthogonally to each other. A solution for two polarizations and multiple frequencies is not removable. Another disadvantage is the expense layered structure with four different layers lying dielectric layers.

In contrast, broadband antennas can also be used in neighboring beard frequency ranges or over a very wide range quenzband are operated. However, there are none different, in particular variably adjustable Emission characteristics for the different frequencies areas achievable. In the previous publication "Electronic Letters ", March 2000, Vol. 36, No. 6, pp. 487-488 are from the publication by D. H. Werner and D. Lee "Design of dual-polarized multiband frequency selective surfaces using fractal elements "dual polarized fractal anten known structures in a large frequency band  can be operated. However, these include antennas structures no separately adjustable radiation diagram me.

From WO 98/43315 a transmitting / receiving antenna is knows which for a first polarization on the individual The antenna array is provided by duplex filters thereby the antenna array for the reception frequency range (Rx) and for the transmission frequency range (Tx) in different Split inputs and outputs. If decoupling for the different frequencies (Rx - Tx) do not exceed the orthogonal polarization takes place, so is disadvantageous Way at least one isolation amplifier in one of the two Frequency bands at the duplex filter inputs and outputs necessary. Isolation amplifiers are also required because insufficient decoupling between the frequency bands (Rx and Tx) can be achieved. It is still no suggestion for generating different lowering angles removable for different frequency ranges.

The object of the present invention is therefore a To create antenna arrangement, which when operating in different frequency bands a different, especially adjustable radiation characteristic preferred without additional active components enables. Nevertheless, a high decoupling should be preferred tion between the two frequency bands can be realized.

The task is according to the invention in accordance with solved claim 1 specified features. Advantageous configurations  the invention are set out in the dependent claims give.

It must be described as surprising that he antenna device according to the invention already with a very low filter effort an independent setting of Beam pattern enables. So almost un dependent radiation characteristics already with one Barrier attenuation of the crossovers even below approx. 15 dB, e.g. B. from 8 to 12 dB can be realized.

What is particularly surprising here is that filter structures can be used to interconnect allow by means of a passive feed network and thereby at the same time a sufficiently high decoupling between the different frequency bands for each polarization exhibit.

According to the invention, this can be done in the form of crossovers a frequency-selective filter structure can be realized, which prefers an up with sufficient barrier damping division of a frequency band into two sub-frequency bands allowed. The use of a fixed dining network or preferably a variably designed dining network now using phase shifters allows it interconnect the individual radiators so that for the the respective frequency range the desired setting of the Radiation diagram can be made, d. H. that in particular the vertical drop angle corresponding to the Desires and necessities preferably set separately  can be.

Finally, because of a low barrier loss for the slide Gram shaping is sufficient, but nevertheless high Decoupling values of, for example, 30 dB and more are requested, it arises according to a particularly be preferred embodiment of the invention, an additional Chen filter effort to put at the feed entrance. This allows that per polarization to increase the decoupling only an additional filter is necessary. This allows highly selective, for each dipole or dipole group provided additional filters can be avoided.

The invention is explained below with reference to exemplary embodiments play explained in more detail. The following show in detail:

Fig. 1 shows a first embodiment of an antenna array with four dipoles, which are switched together with a fixed feed network;

Fig. 2 shows a modified embodiment of Figure 1, in which the interconnection device for a frequency range by means of a fixed interconnection and the interconnection for a second frequency range by means of phase shifters is made variable;

FIG. 2a shows an enlarged detail from FIG. 2 to illustrate a phase shifter;

Fig. 3 shows a further embodiment, in which chem for both frequency ranges to collect circuit via phase shifter varia bel is made;

FIG. 4 shows an antenna array with dual-polarized antenna and two frequency ranges, in which takes place with the interconnection means of phase shifters for each polarization for each frequency range;

Fig. 5 shows an embodiment of a dual-band antenna, wherein the second band is frequency selective divided in a frequency band f2 and f3 and thus a three-band antenna results; and

Fig. 6 shows a modified from FIG. 2 execution example to illustrate that a crossover and a group of at least two individual radiators is assignable.

The first exemplary embodiment according to FIG. 1 is discussed below. The antenna array shown schematically therein comprises four individual radiators 1 , in the exemplary embodiment shown in the manner of dipoles 1 ', which are usually arranged in front of a reflector which is arranged vertically, for example in the vertical direction.

The individual radiators 1 are fed via feed connections 5.1 and 5.2 via a fixed or hard-wired feed network 7 . Accordingly, the number of individual radiator 1 is effected by each feed terminal 5.1 and 5.2 of continuous multiple branching of the feed lines 9, namely, from the feed terminal 5.1 via the feed line 9 and a branch point 11 point in the feed branch lines 9.1 and about the respective subsequent branch 13 for subsequent supply branch line 9.2 . The same applies accordingly to the further supply connection 5.2 with the feed line 109 , the branch point 111 , the feed branch lines 109.1 , the branch points 113 and the feed branch lines 109.2 . The feed lines simultaneously contain impedance transformers, which are not shown for the sake of simplicity.

The individual radiators 1 are each connected via a line 17 to a radiator-side connection 19 with a frequency crossover 21, via which the radiator-side connection 19 is connected to two connections 23.1 and 23.2 on the supply network side, specifically for a first frequency band 21 and a second frequency band f2 , The crossovers 61 can be constructed by a frequency-selective filter structure.

The respective feed branch lines 9.2 and 109.2 are connected to the connections 23.1 and 23.2 on the supply network side, so that all the individual radiators 1 are selectively connected to the supply connection 5.1 for the first frequency band f1 and the supply connection 5.2 for the second frequency band f2.

The crossovers 21 are with sufficient Sperrdämp tion of z. B. 15 dB or even less than 10 dB in the at least two sub-frequency bands. The interconnection can be carried out in such a way that the setting of the radiation diagram is preset differently for the respective frequency band. The presetting can take place in such a way that, for example, the vertical lowering angles are different for both frequency bands.

The embodiment according to FIG. 2 largely corresponds to that according to FIG. 1, but with the difference that for the one frequency band f2 there is no fixed interconnection at the branching points 113 , but that in each case variably adjustable phase shifters 27 are provided. The phase shifters can be constructed in such a way as is basically known from WO 98/21779. In other words, an adjusting member 31 , which is adjustable about a pivot axis 29 , is provided, which is connected to the feed connection 5.2 via a line 109 and 109.1 . This setting member 31 is, for example, galvanically or capacitively connected to a part-circular contact or coupling element 33 , which is electrically connected at its opposite end regions to phase shifter connections 35 , from which lines 109.2, starting from the respective feed branch, connect to the feed network connections 23.2 on the frequency ranges 21 it follows. The so-called partially circular contact or coupling element 33 in the exemplary embodiment shown is built up before in stripline technology or in micro-stripline technology, namely on a base plate 28 (ground plate).

The radiation diagram for the first frequency band f1 thus follows via the fixed feed network part, as a result of which a specific radiation diagram is predefined. Via the variably adjustable phase shifter elements 27 , however, it follows the setting of the radiation diagram with respect to the second frequency band f2 via a variable feed network, so that the radiation shaping and thus in particular the radiation reduction, ie the reduction angle for the main lobe, can be set differently within the frequency band f2.

The embodiment according to FIG. 3 is modified compared to that according to FIG. 2 insofar as a feed network 7 is seen here for both frequency bands f1 and f2, that a corresponding beam shaping is provided in both frequency bands f1 and f2 and thus in particular a differently adjustable one and / or changeable vertical lowering of the main lobes.

In the exemplary embodiment according to FIG. 4, an antenna array is now used which does not consist of single radiators 1 , but of dual-polarized radiators 2 . These dual-polarized radiators 2 can be composed, for example, of a dipole square or a dipole cross, that is to say using single dipole radiators 1 . Correspondingly, each dipole single radiator of a dual-polarized dipole cross 2 (or, for example in the case of a dipole square, two parallel dipole radiators each) is connected via a common line 17 or 17 'to a crossover 21 . Thus, as can be seen from FIG. 4, two lines 17 , 17 'proceed from each of the four dipole radiators, each of which leads to the radiator-side connection 19 of the crossovers 21 . With four dual-polarized dipole radiators 2 , eight crossovers are thus provided. In general, 2 n crossovers 21 are therefore required in this exemplary embodiment for n dual-polarized dipole radiators. In Fig. 5, the connection 5.1 at the top for the frequency f1 is assigned to the polarization + 45 °, in FIG. 4 the connection 5.1 'at the bottom is associated with the frequency f1 of the negative polarization -45 °, so that the shown in Fig. 4 and joined together to form a dipole antenna Dipolkreuz ° / -45 ° orientation are arranged in a + 45.

The dipoles 1 a and 1 b of the dual-polarized dipole radiators 2, which are each aligned parallel to one another, are brought together frequency-selectively via two downstream feed networks, in the exemplary embodiment according to FIG. 4, frequency-selectively via respectively assigned phase shifters 27 . As a result, the radiation diagram and in particular the angle of attenuation can be set and / or changed separately for each polarization both for a first and for a second frequency f1 and f2.

Finally, reference is made to the exemplary embodiment according to FIG. 5. FIG. 5 shows an arrangement also for a dual-polarized antenna 2 , each of the dual-polarized antennas 2 provided according to FIG. 5 comprising a cross dipole 2 'and a dipole square 2 ' surrounding the cross dipole 2 '.

The individual jets 1 a and 1 b of the dipole square 2 ", which are arranged in parallel to one another, are connected via a varia bles feed network 7 , with each of the equally radiating and, in this case, parallel arranged single emitters 1 a of an emitter arrangement 2 " together in pairs with the same parallel alignment angeord Neten individual radiators 1 a a second radiator arrangement 2 are "interconnected via a phase shifter 27, and 27 in turn cause the supply connection side terminals of the phase shifter via a branch point 211 to a common feed terminal 5.3. Entspre same applies to the second polarization of these Dipolqua dratanordnung, wherein which via the feed terminal 5.3 'connect through the downstream branch point 211' to the phase shifters 27 and each of the two outputs to the respective two parallel Dipolstrahlerb 1 b is carried out a respective antenna element arrangement 2 ".

The connections 5.3 and 5.3 'thus serve to receive or transmit a third frequency band with a first and a second polarization. The frequency band f3 can e.g. B. are at 824 to 960 MHz.

With regard to the cross dipoles 10 'arranged in the interior of the dipole squares, on the other hand, a frequency-selective division into two frequency bands f1 and f2 takes place, the feeder connection-side outputs then in turn for each of the two polarizations in accordance with the exemplary embodiment according to FIG. 4 via phase shifters 27 with the two feed connections for f1 and f2 are connected together. The frequency band f1 can e.g. B. 1920 to 2170 MHz and the second frequency band f2 cover a range from 1710 to 1880 MHz.

Fig. 5 thus shows a dual-polarized antenna with band segments, wherein the radiation pattern and in particular the depression angle for all three frequency bands and both orthogonal polarizations is different from a adjustable.

Deviating from the last-mentioned example, a frequency-selective band division could of course also be provided for the third frequency band. In the same way, if required for a single frequency band, a fixed circuit could be implemented without an individually adjustable lowering angle, as is shown schematically, for example, in FIG. 2.

In all exemplary embodiments, the crossovers can  preferably be realized by filter structures that in particular also be integrated in the housing of the antenna can. The filter structures can also be made of ge shielded stripline structures or from triplates structures exist.

Alternatively or in part alternatively and in addition can the filter structures are also formed from coaxial filters his.

It can be seen from the exemplary embodiments explained lich that the corresponding antennas at least two Include single radiators. But it can also be more than two Single radiators can be provided that lead to a common Group belong. There is only one group of single beams learn possible, but also several groups of single beams learn how, for example, with dual polarized antennas NEN is described.

In order to achieve good decoupling, the Fre a minimal blocking loss compared to the each other frequency range of at least 6 dB, 8 dB or have 10 dB. This value should preferably be at least 15 dB, in particular at least 20 dB.

The blocking attenuation in the other frequency band if necessary to increase additionally, can be in the off The antenna has additional filters after the connection circuit by means of the feed network mentioned hen. An improvement in heat dissipation can  can also be realized in that the fil ter be attached to the reflector plate. You can the filters on the refector plate mechanically on top of each other be stacked.

Referring to Fig. 6 shows a modification is shown in principle in accordance with all illustrated embodiments of FIGS. 1 to 5 can be applied.

In the embodiment shown in FIG. 6 it is clear that, for example, deviations from FIG. 2, z. B. a group 100 with two individual radiators 1 is assigned to a crossover 21 . The group 100 of individual emitters 1 can not only have two individual emitters 1 , 1 ', but also, for example, several individual emitters 1 , 1 '. B. include three individual radiators, for example, can be assigned to an input of a crossover 21 via a common summing point and an ordered line.

With reference to FIG. 6, it is additionally shown what can also come into effect in all other exemplary embodiments that additional filters 121 can be provided, which are preferably assigned in the output of an antenna after interconnection by means of the feed network 7 , and preferably on the reflector plate can be attached. By setting up these additional filters 121 , the blocking effect of the filters 21 for the downstream individual radiators can be further improved in a cost-effective and simple manner.

Claims (21)

1. Antenna with the following features
with at least two individual radiators ( 1 , 2 ),
the at least two individual radiators ( 1 , 2 ) can be operated in at least two frequency bands (f1, f2,..., fn),
each output of the individual radiators ( 1 ) which can be operated in at least two frequency bands (f1, f2,..., fn) or the output from a group of corresponding individual radiators ( 1 ) is assigned to a crossover ( 21 ), the frequency band present at the radiator-side connection being present Connections on the supply network side ( 23.1 , 23.2 ) in at least two sub- frequency bands (f1, f2, ... , fn) are present separately,
A feed network ( 7 ) is constructed in such a way that the feed-side connections ( 23.1 , 23.2 ) on the crossover ( 21 ) for the respective sub- frequency band for radiation shaping and in particular for different setting of the lowering angle of the main lobe with predeterminable or changeable adjustable phase and / or Amplitude are interconnected. 2. Antenna according to claim 1, characterized in that a crossover network ( 21 ) is assigned to a group ( 100 ) of at least two individual radiators ( 1 , 1 '). 3. Antenna according to claim 1 or 2, characterized in that at least one additional filter for polarization Increasing the decoupling is provided, which is preferred the supply connection (5.1, 5.2,..., 5.n) before or after is switched. 4. Antenna according to one of claims 1 to 3, characterized ge indicates that for each polarization to increase the Decoupling an additional filter is provided, which is preferred the associated supply connection (5.1, 5.2,.. 5.n) is connected upstream or downstream. 5. Antenna according to one of claims 1 to 4, characterized in that at least with respect to a frequency band of (f1, f2, ... , Fn) the outputs ( 23.1 , 23.2 ) of the frequency crossovers ( 21 ) via assigned phase shifters ( 27 ) are at least indirectly connected to the respective supply connection (5.1, 5.2,..., 5.n). 6. Antenna according to one of claims 1 to 5, characterized in that all individual radiators ( 1 , 2 ) or groups ( 2 , 2 ', 2 ") of individual radiators via the assigned crossovers ( 21 ) and assigned phase shifters ( 27 ) are connected together with the assigned supply connections (5.1, 5.2,.., 5.n) in such a way that the radiation diagram and, in particular, the setting of the lowering angle of the main lobe can be set differently with respect to all frequency bands. 7. Antenna according to one of claims 1 to 6, characterized ge indicates that at least two single emitters are provided hen are. 8. Antenna according to one of claims 1 to 7, characterized in that at least two dual polarized radiator arrangements ( 1 , 2 ) are provided. 9. An antenna according to any one of claims 1 to 8, characterized in that the antenna element arrangements (1, 2) dual polarized individual radiators (1, 2) comprise beams for each of the polarizations in two different frequency bands, wherein an at least for one polarization Fre quency band splitting is provided via a fixed or a variable feed network ( 7 ) using phase shifters ( 27 ). 10. Antenna according to one of claims 1 to 9, characterized in that the crossovers ( 21 ) are formed from filter structures, which in particular comprise shielded stripline or triplate structures. 11. Antenna according to one of claims 1 to 10, characterized in that the crossovers ( 21 ) are formed from filter structures which include coaxial filters. 12. Antenna according to one of claims 1 to 11, characterized in that the crossovers ( 21 ) have a minimal blocking attenuation with respect to the other frequency band of at least 6, 8 or 10 dB, in particular at least 15 dB, preferably at least 20 dB. 13. Antenna according to one of claims 1 to 12, characterized in that the interconnection of the frequency soft ( 21 ) in two frequency bands (f1, f2) by means of un adjustable phase shifters ( 27 ). 14. Antenna according to one of claims 1 to 13, characterized in that the interconnection of the frequency filter ( 27 ) is fixed for at least one frequency band and is variably provided for at least one further frequency band by means of a phase shifter ( 27 ). 15. Antenna according to one of claims 1 to 14, characterized in that at least further independent individual radiators ( 2 ') are provided for at least one further frequency band (f3), so that the antenna in at least three frequency bands (f1, f2,.. ., fn) is operable. 16. Antenna according to one of claims 1 to 15, characterized in that the feed network ( 7 ) using filter filters ( 21 ) is constructed such that a division into more than two frequency bands is provided. 17. Antenna according to one of claims 1 to 16, characterized in that in addition to the crossovers additional filters ( 121 ) are provided, which are preferably each associated with at least two crossovers ( 21 ). 18. Antenna according to claim 17, characterized in that the additional filters ( 121 ) are preferably arranged on the feed connection ( 5.1 , 5.2 ) and / or in the area of the feed line ( 109 ). 19. Antenna according to one of claims 1 to 18, characterized in that the filters, ie the filter switches ( 21 ) and / or the additionally provided filters, which are assigned to the output of an antenna after interconnection by means of the feed network ( 7 ), on Reflector sheet are attached. 20. Antenna according to claim 19, characterized in that the filters on the reflector plate mechanically on top of each other are stacked. 21. Antenna according to one of claims 1 to 20, characterized characterized that the filter structures in the housing the antenna are integrated.