This application is the U.S. national phase of International Application No. PCT/EP2007/006863, filed 2 Aug. 2007, which designated the U.S. and claims priority to German Application No. 10 2006 039 279.5-55, filed 22 Aug. 2006, the entire contents of each of which are hereby incorporated by reference.
The invention relates to a dipole-shaped radiator arrangement according to the preamble of claim 1.
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Dipole antennas are known for example from the prior publications DE 197 22 742 A and DE 196 27 015 A. Dipole antennas of this type may have a conventional dipole construction or, for example, be formed from a crossed dipole or a dipole square, etc.
What is known as a vector dipole is known for example from the prior publication WO 00/39894. The construction thereof appears to be comparable to a dipole square. However, owing to the specific configuration of the dipole antenna in this prior publication and the particular way of feeding this dipole antenna, it operates in a similar manner to a crossed dipole which radiates in two polarization planes which are perpendicular to one another. In terms of its construction, it is rather square-shaped as a result of the outer contour configuration thereof in particular.
WO 2004/100315 A1 discloses a further configuration of the aforementioned vector dipole, in which the entire faces of each radiator half of one polarization can be closed to a large extent.
Dipole antennas of this type are conventionally fed in such a way that one dipole or radiator half is DC connected (i.e. galvanically) to an outer conductor, whereas the inner conductor of a coaxial connection cable is DC connected to the second dipole or radiator half (i.e. again galvanically connected). In each case, power is fed to the end regions of the dipole or radiator halves facing towards one another.
It is known from WO 2005/060049 A1 to feed the outer conductor by means of a capacitive outer conductor coupling. The support means or each associated half of the support means of the radiator arrangement can for this purpose be coupled to ground capacitively at the foot region or the base of the support means (in this case the outer connector of a coaxial feed line is generally preferably connected electrogalvanically to the reflector underneath the base of the support means).
A conventional, i.e. known from the prior art, feed means of a dipole of this type is shown in a sectional view in
Likewise, the half 9′, shown for example on the left in
As can be seen from
In a modified embodiment disclosed in WO 2005/060049, an axial hole 11″ is also provided in the second half 9″ of the support means 9 in such a way that a coaxial line arrangement is again formed, namely with an inner conductor 13 which extends from a matching network on the lower side of the reflector 105 via the first hole 11′ in the first half 9′ of the support means 9, thus forming a first inner conductor portion 13a, the inner conductor 13 then transitioning via an inner conductor or connection portion 13b, which extends at least approximately parallel to the reflector 105, into a third inner conductor portion 13c which passes from above into the second hole 11″ of the second half 9″ of the support means 9 and terminates freely approximately in the lower third of the support means 9 without contacting the electrically conductive support means 9. This is preferably achieved by using an insulator which is inserted in the holes 11′, 11″ is penetrated by the inner conductor 13 and is held thereby. In other words, the central inner conductor portion 13b is not galvanically connected to the associated dipole half 1b, 1′b at the feed point 17 but an inner conductor coupling is formed at this point instead.
A further device of the prior art is known from U.S. Pat. No. 4,668,956. This prior publication discloses a dipole antenna which in one embodiment comprises two dipole halves and in a further embodiment comprises two dipoles which are positioned so as to be offset relative to one another by 90°. Each dipole antenna comprises a tubular support means which is electrogalvanically connected to the reflector. Guided inside this support means, which serves as an outer conductor, is an inner conductor which projects from the rear of a hollow cylindrical support means and is fed at that point. At the height of the dipole halves, the inner conductor is guided approximately parallel to the reflector plane in the direction of the second half of the hollow cylindrical support means so as to then run back towards the reflector inside the second hollow cylindrical support means. The inner conductor terminates therein at a distance from the reflector plane and is electrogalvanically connected to the hollow cylindrical, electrically conductive support half via a short circuit element.
An electrogalvanically conductive lug, which projects parallel to the reflector plane and on which the dipole halves engage, is arranged on each of the two hollow cylindrical support means at the height of the end remote from the reflector.
The object of the present invention is to form, on the basis of the prior art mentioned at the outset, a dipole-shaped or dipole-like radiator arrangement which achieves even greater bandwidth.
The object is achieved according to the invention by the features specified in claim 1. Advantageous embodiments of the invention are specified in the sub-claims.
According to the invention, it is now provided that the inner conductor, which in the state of the art terminates freely inside the second half of the support means, is extended and DC connected (i.e. galvanically) to ground potential. In other words, one of the ends of the inner conductor is connected to the feed network (as in the prior art), whilst the other end of the inner conductor is now DC connected to ground.
This completely astonishing construction enables a marked improvement in the bandwidth of a radiator of this type to be achieved. In this case, the radiator is fed by a non-galvanic inner conductor feed means, it thus being possible to also use different materials (such as aluminium, a plastics material provided with a metal-coated surface, etc.) for the radiator, since no solder connections are required.
In contrast to the solution according to U.S. Pat. No. 4,668,956, the invention is based on a dipole-shaped or dipole-like radiator arrangement which radiates for example in one or two polarization planes, the radiator arrangement, comprising the dipole and/or radiator halves and the support means, including the base, as a whole being electrically conductive, but is nevertheless galvanically isolated via the reflector or ground plane, i.e. is preferably capacitively coupled to the ground or reflector surface. In addition, the end of the inner conductor, which is guided back towards the ground or reflector surface (i.e. the end opposite to that to which an appropriate signal is fed), is, according to the invention, not electrogalvanically connected to the support means, which is hollow cylindrical in form for example and encloses the inner conductor, but is connected to the ground and/or reflector surface.
In a particularly preferred embodiment, the base of the support means of the radiator arrangement is capacitively coupled to the reflector or to ground.
However, it is also possible to connect the base of the support means of the radiator galvanically to the reflector or ground.
Even if the base of the support means of the radiator arrangement is coupled capacitively to ground or to the ground surface, the length of the inner conductor and thus the height of the feed plane which is at a distance from the reflector or ground plane is generally selected in such a way that said feed plane is approximately at the height of the dipole or radiator halves. This feed plane is often positioned somewhat lower. The feed plane may for example preferably be located at any height between λ/10 below the radiator plane and λ/6 above the radiator plane, preferably however not more than λ/10 above the radiator plane. In this case, λ represents a wavelength of the frequency band to be transmitted, preferably approximately the average wavelength of the frequency band to be transmitted.
The height of the radiator may be in the conventional range of λ/4 over ground (i.e. the reflector or ground). This height should in any case preferably not fall below a value of λ/10. In principle, there is no upper limit so the radiator height may in principle be any desired multiple of λ (especially since a radiator has a radiation pattern even if there is no reflector). However, λ preferably only represents a wavelength from the frequency band to be transmitted, preferably at an average frequency of the frequency band to be transmitted.
The invention will be described in greater detail below with reference to an embodiment. In the figures:
a: is an axial sectional view through a dipole according to the prior art comprising a conventional feed means;
b: is a cross-section along the line II-II in
The construction of a dipole-shaped radiator 1 is shown in
The embodiment according to the invention shown in
Secondly, the embodiment according to the invention shown in
In this embodiment, it is indicated that the base, which is electrically conductive or provided with an electrically conductive coating, of the support means 9 (which shall be referred to at some points below as the support 9) is capacitively coupled to the ground surface 5, for which purpose a sheet-shaped, plate-shaped or film-shaped insulator 21 is provided between the lower side of the base 7 of the dipole radiator 1 and the ground surface 5 or the reflector 105.
The inner conductor 13 is guided over its entire length 13 in such a way that it is electrogalvanically isolated from the support 9 in a conventional manner by inserting insulator sleeves, through which the inner conductor 13 passes, in the axial holes 11′ and 11″. This ensures that there is no direct current (galvanic) contact between the inner conductor 13 and the electrically conductive support 9.
For this purpose, holes or passages 109 are formed on the upper end of the support means 9 in order to guide the inner conductor from one half 9′ of the support means 9 transversely to the other half 9″ of the support means 9 along what is known as the feed plane 15, the inner conductor penetrating the axial hole 11″ of the second support half 9″ from above.
In this way, in accordance with the embodiment according to
As is also shown in the embodiment in
A dual-polarized radiator 1″, the mode of operation of which is known in principle from WO 00/39894 A1, WO 2004/100315 A1 and WO 2005/060049 A1, is shown in a three-dimensional view in
In the sectional view shown in
It can be seen that the configuration and arrangement of the inner conductor 13 in relation to the polarization plane is similar to that of the radiator arrangement 1 in the form of a simple dipole 1′ which was explained with reference to
At the upper end of the insulating sleeve, the second inner conductor portion 13b extends at a right angle to the first inner conductor portion 13a, i.e. parallel to the plane of the ground surface 5 or of the reflector 105 and therefore also parallel to the radiator halves 1a, 1b, towards the second support half 9″, where the inner conductor passes into its third inner conductor portion 13c which in turn extends parallel to the first inner conductor portion 3a, i.e. approximately at a right angle to the second inner conductor portion 13b, and is thus arranged at a right angle to the ground surface 5.
At its lower end 19′, the first inner conductor portion 13a is again guided through a hole 35 (as shown in
In this embodiment, the second end 19″ of the inner conductor 13 in the second support half 9″ is also guided through the reflector 105 or the printed circuit board 205 via a hole 35′ with no electrical contact and, at the rear of the electrical circuit board 205, is DC (i.e. galvanically) connected to the ground surface 5 provided on the radiator side 205a via an electrical connection 23 and a plurality of subsequent feedthroughs 25. The aforementioned electrical connection 23 may in this case be formed so as to be planar, but may also assume any other shape Likewise, the inner conductor may also be galvanically connected directly to the ground surface 5 on the upper side of the printed circuit board (as shown in
The feed plane 15 is in this case again represented (at least approximately) by the central inner conductor portion 13b.
In a vector radiator, as shown in a sectional view in
If the ground surface 5 is formed on a substrate 205 for example, said ground surface can also be covered with an insulating coating layer in such a way that a capacitive coupling is formed between the conductive base 7 of a radiator assembled thereon and the ground surface 5 which is isolated by the coating layer.
With respect to the radiator halves 1a and 1b shown in section in
Since the embodiment shown in
The described construction with the inner conductor arrangement according to the invention enables the two ends 19′ and 19″ to be guided to the rear of the reflector 105 or the rear or underside of a dielectric substrate 205. This also enables the dipole radiator to be mechanically fixed for example, by soldering one feed end 19′ of the inner conductor 13 to the matching network 37 on the rear of the reflector 105 or the substrate 205, and soldering the second end 19″ of the inner conductor 13 to the aforementioned electrical connection 23 by means of which the connection to the ground surface 5 on the radiator side of the substrate 205 is produced via subsequent feedthroughs 25.
In addition, however, a screw connection may also be used, for example by using a screw 51, which can be electrically conductive or non-conductive depending on whether it is used capacitively or galvanically and is screwed into the base from the rear of the reflector or substrate. Adhesive or double-sided adhesive tape or adhesive film may also be provided between the lower side of the base and the upper side of the reflector or substrate to fix the radiator arrangement.
The length of the inner conductor 13, i.e. the length of the inner conductor portion 13a or 13c, should extend from a respective lower end 113′ or 113″ at the height of the ground surface 5 to the height of the feed plane 15 or 15′ and be of a length which is for example no more than λ/10 below the radiator plane defined by the radiator halves 1a and 1b (or dipole halves 1′a and 1b) and no more than λ/6 above this radiator plane. It is particularly beneficial for the feed plane to be no more than λ/10 below the radiator plane and no more than λ/10 above the radiator plane. In this case λ represents a wavelength of the frequency band to be transmitted, preferably the average frequency of the frequency band to be transmitted.
Independently thereof; the distance from the radiator or dipole halves 1a, 1b or 1′a or 1′b to the ground surface 5 and/or the reflector 105 can be selected in such a way that this distance is preferably approximately λ/4 over the ground or the reflector. This radiator height should preferably not fall below a value of λ/10. Using suitable balancing means, feed variants and/or suitable matching networks may enable an even lower radiator plane to be achieved in some circumstances (planar antennas).
The aforementioned matching circuit or matching network 37 is provided in order to be able to carry out suitable matching and transformation processes in the lower end region of the inner conductor 13 or the inner conductor portion 13a.
Number | Date | Country | Kind |
---|---|---|---|
10 2006 039 279 | Aug 2006 | DE | national |
Filing Document | Filing Date | Country | Kind | 371c Date |
---|---|---|---|---|
PCT/EP2007/006863 | 8/2/2007 | WO | 00 | 2/20/2009 |
Publishing Document | Publishing Date | Country | Kind |
---|---|---|---|
WO2008/022703 | 2/28/2008 | WO | A |
Number | Name | Date | Kind |
---|---|---|---|
3740754 | Epis | Jun 1973 | A |
4042935 | Ajioka et al. | Aug 1977 | A |
4218685 | Frosch et al. | Aug 1980 | A |
4668956 | Mahnad | May 1987 | A |
5929820 | Caulfield et al. | Jul 1999 | A |
7710342 | Schadler et al. | May 2010 | B2 |
20040201537 | Stolle et al. | Oct 2004 | A1 |
20050134517 | Gottl | Jun 2005 | A1 |
Number | Date | Country |
---|---|---|
196 27 015 | Jan 1998 | DE |
197 22 742 | Dec 1998 | DE |
2 840 455 | Dec 2003 | FR |
WO 0039894 | Jul 2000 | WO |
WO 2004100315 | Nov 2004 | WO |
WO 2005060049 | Jun 2005 | WO |
Number | Date | Country | |
---|---|---|---|
20100007571 A1 | Jan 2010 | US |