Not applicable.
Not applicable.
The technology herein relates to a multilayer antenna of planar construction.
Patch antennas or what are known as microstrip antennas are sufficiently well known. They conventionally comprise an electrically conductive base, a dielectric carrier material arranged thereabove and an electrically conductive radiation face provided on the upper side of the dielectric carrier material. The upper radiation face is generally stimulated by a supply line extending transversely to the aforementioned planes and layers. The connection cable used is usually a coaxial cable, the outer conductor of which is electrically connected to the ground conductor at a terminal, whereas the inner conductor of the coaxial cable is electrically connected to the radiation face located at the top.
Multilayer antennas of planar construction have, for example, become known in the form of what are known as stacked patch antennas. This type of antenna allows the bandwidth of such an antenna to be increased or resonances to be ensured in two or more frequency ranges. Antennas of this type may also be used to improve the antenna gain.
The prior publication IEEE TRANSACTIONS ON ANTENNAS AND PROPAGATION, VOL. AP-27, NO. 2, MARCH 1979, pages 270 to 273, describes a multilayer patch antenna allowing resonance in two frequency ranges. The patch antenna accordingly has, for example, in addition to the bottom ground face and the radiation face arranged offset with respect thereto and stimulated via a supply line, a patch face arranged above, and laterally offset with respect to, the radiation face. The carrier material between the ground face and the radiation face and also between the radiation face and the patch face located thereabove consists, in each case, of a substrate having a uniform dielectric constant.
A patch antenna comprising carrier layers having different dielectric constants has become known, for example, from the prior publication IEEE TRANSACTIONS ON ANTENNAS AND PROPAGATION, VOL. 47, No. 12, DECEMBER 1999, pages 1780 to 1784. Foam is used as the upper carrier layer for the upper metallic face (patch face). The distance between the upper patch face and the radiation face located therebelow corresponds to the distance between the radiation face and the lower ground face.
The prior publication IEEE TRANSACTIONS ON ANTENNAS AND PROPAGATION, VOL. 47, No. 12, DECEMBER 1999, pages 1767 to 1771, among other documents, demonstrates that antenna gain may be increased using multilayer patch antennas.
Finally, a generic antenna having a multilayer construction has become known, for example, from U.S. Pat. No. 5,880,694 A. The antenna comprises a lower ground face, a dielectric carrying member located thereon and having a radiator face located on its upper side. Above the radiator face there is arranged a further dielectric member on which there is provided, on the side remote from the lower ground face, an electrically conductive patch face.
A drawback of all previously known antenna arrangements of this type is the comparatively complex construction. For, in the use of conventional commercial patch antennas having a ground face, an electric carrying member (substrate) located thereon and a radiation face located thereabove, it is invariably complex to supplement an antenna of this type to form a multilayer antenna. Depending on the use of conventional commercial patch antennas, which comprise at least a lower ground face, a substrate made from a dielectric material, for example ceramics, and a radiation face located thereon, a dielectric carrier layer, possibly of variable thickness, would then have to be produced in each case and, for example, positioned and secured on the radiation face of the conventional commercial patch antenna in order then to arrange the electrically conductive patch face on the upper side of this additional dielectric carrying layer. A different, but also highly complex, construction would involve, for example, equipping an antenna housing, below which a conventional commercial patch antenna is integrated, with an additional electrically conductive patch face; however, this would also require complex additional constructional measures.
The exemplary illustrative non-limiting implementation provides an improved multilayer antenna of planar construction, in particular a patch antenna, which, to achieve the electrical characteristics known per se, is provided with a patch radiator provided above the radiation face and which is also of simpler overall construction and/or has improved electrical characteristics.
The solution according to exemplary illustrative non-limiting implementations allows numerous advantages to be achieved.
A basic non-limiting advantage (and one that is highly surprising) is that the exemplary illustrative non-limiting antenna has significantly improved antenna characteristics compared to simple, normal patch antennas. This is all the more surprising in view of the fact that the radiation structure provided at the very top of the patch antenna is arranged at an extremely small distance above the radiation face of the patch antenna and may therefore, in an exemplary illustrative non-limiting implementation, even have longitudinal and transverse extensions which are greater than the radiation face located therebelow. After all, in such a case, the uppermost patch face would be expected adversely to influence the radiation pattern.
A further basic advantage of the exemplary illustrative non-limiting antenna is that conventional commercial patch antennas having a ground face and a radiation face and a dielectric located therebetween—preferably, for example, what are known as ceramic patch antennas—may be easily used without having to be constructionally altered. All that is required is to fasten the three-dimensional electrically conductive structure of the uppermost patch face to a conventional commercial patch antenna using a suitable adhesion and/or fastening layer.
In other words, an additional carrier structure or hood is not required in order to hold this patch face.
In an exemplary illustrative non-limiting implementation, an adhesion layer, in the form of a double-sided adhesive tape or in the form of a comparable adhesion means, is used as an adhesion structure between a conventional commercial patch antenna and the uppermost conductive three-dimensional patch element, allowing simple fastening of the uppermost patch element to a conventional patch antenna.
In an exemplary illustrative non-limiting implementation, the distance between the three-dimensional patch element and the radiation face of a patch antenna is greater than 0.5 mm, in particular greater than 1 mm, for example about 1.5 mm. Although the distance may be even greater, such a small distance between the three-dimensional patch element and the radiation face of a multilayer patch antenna is, in principle, entirely sufficient.
The three-dimensional structure of the patch element may, for example, be provided by what is known as a volume member which, in addition to its two-dimensional extension (comparable, for example, to conventional metal plates or metal layers), also has a significantly greater height or thickness of one or more millimeters.
However, alternatively, it is also possible, for example, for a three-dimensional patch element of this type, arranged above the radiation face, to be equipped with a wholly or partially peripheral edge or web edge, providing effectively a three-dimensional structure. This opens up the possibility for the patch element provided with a three-dimensional structure to be formed by a metal sheet or punched part in which edge portions, which revolve from a two-dimensional element and are oriented transversely and preferably perpendicularly to the plane of the patch element, are upwardly positioned. In the corners, the individual flange or edge portions do not necessarily have to be electrically or electrogalvanically connected to one another. The given electrical connection of a positioned edge element to an adjacent edge element is provided via the central portion, oriented substantially parallel to the radiation and ground face located therebelow, of the patch element.
The aforementioned three-dimensional structure (which is referred to as a “three-dimensional” structure because it has a significantly greater material thickness or material height than metal plates or metal foils used according to the prior art) does not necessarily require the entire member to be configured as what is known as a volume member or the aforementioned peripheral edge necessarily to encircle the entire edge portion of the patch structure. Edge or web elements provided only in certain sections are also sufficient. Recesses or even, for example, a concave deformation of the patch face facing the radiation face located therebelow may also be provided in the patch face itself. However, recesses, which protrude, for example, from the peripheral edge into the patch face, may also be formed in the patch face.
Also possible is the use, for example, of a dielectric member which is made from plastics material and is coated with an electrically conductive layer. On use of a “volume member” of this type having a thickness or height of, for example, more than preferably 0.5 mm or 1 mm, in particular more than 1.5 mm, said member should be provided, at least on a side located parallel to the radiation face, preferably on the side located adjacent to the radiation face and on its peripheral wall or edge portions, with an electrically conductive layer. The upper side, remote from the radiation face of the patch antenna, of the electrically non-conductive member may also, if required, be equipped with an electrically conductive layer.
These and other features and advantages will be better and more completely understood by referring to the following detailed description of exemplary non-limiting illustrative implementations in conjunction with the drawings of which:
a shows a further exemplary illustrative non-limiting implementation;
b is a plan view of the exemplary illustrative non-limiting implementation according to
The patch antenna shown in
It is apparent from the schematic sectional view according to
This dielectric carrier 5 has a sufficient height or thickness, which generally corresponds to a multiple of the thickness of the ground face 3; i.e., in contrast to the ground face 3, which basically consists merely of a two-dimensional face, this dielectric carrier 5 is configured as a three-dimensional member having sufficient height and thickness.
On the upper side 5a opposing the lower side 5b (which becomes adjacent to the ground face 3) there is configured an electrically conductive radiation face 7 which may, again, also basically be understood as a two-dimensional face. This radiation face 7 is supplied with electricity and stimulated via a supply line 9 which preferably extends in the transverse direction, in particular perpendicularly to the radiation face 7, from below, through the dielectric carrier 5 in a corresponding bore or a corresponding channel 5c.
From a connection point 11, which is generally located at the bottom and to which a coaxial cable (not shown in greater detail) may be connected, the inner conductor of the coaxial cable (not shown) is electrogalvanically connected to the supply line 9, and is therefore connected to the radiation face 7. The outer conductor of the coaxial cable (not shown) is then electrogalvanically connected to the ground face 3 located at the bottom.
The radiation face 7 resting on the dielectric 5 may have the same contour or outline 7′ as the dielectric 5 located therebelow. In the illustrated non-limiting implementation, the basic shape is also square in its formation (in adaptation to the outline 5′ of the dielectric 5) but has, at two opposing ends, flat portions 7″ which are formed practically by the omission of an isosceles-rectangular triangle. In general, the outline 7′ may therefore also be an n-polygonal outline or contour or even be provided with a sinuous outer boundary 7′.
The aforementioned ground face 3 and also the radiation face 7 are described in certain respects as being “two-dimensional” faces, since their thickness is so low that they can hardly be described as being “volume members”. The thickness of the ground face and the radiation face 3, 7 is conventionally below 1 mm, i.e. generally below 0.5 mm, in particular below 0.25 mm, 0.20 mm, 0.10 mm.
Above the patch antenna A thus formed, which may, for example, consist of a conventional commercial patch antenna A, preferably of what is known as a ceramic patch antenna (in which, that is, the dielectric carrier layer 5 is made from a ceramic material), there is then additionally arranged, in the case of an exemplary illustrative non-limiting stacked patch antenna according to
The stacked patch antenna thus described is, for example, positioned on a chassis B (illustrated in
The patch element 13 may, for example, consist of an electrically conductive metallic member, i.e., for example, a cuboid having appropriate longitudinal and transverse extensions and sufficient height and thickness.
As is apparent from the plan view according to
In the illustrated non-limiting implementation, the patch element 13 has a longitudinal extension and a transverse extension which, on the one hand, are greater than the longitudinal and transverse extensions of the radiation face 7 and/or, on the other hand, are also greater than the longitudinal and transverse extensions of the dielectric carrier 5 and/or of the ground face 3 located therebelow.
In very general terms, the patch element 13 may also have, entirely or in part, convex or concave and/or other sinuous outlines or an n-polygonal outline, or mixed forms of both, as is shown in plan view, purely schematically, for a differing non-limiting implementation according to
The patch element 13 has a thickness which is not only double, three, four or five times, etc., but rather above all ten times, 20, 30, 40, 50, 60, 70, 80, 90 and/or 100 and more times the thickness of the ground face 3 and/or the thickness of the radiation face 7.
In the illustrated non-limiting implementation, the thickness or height 14 of the patch element 13 is equal to or greater than a spacing 17 formed by the lower side 13b of the patch element 13 and the upper side 7a of the radiation face 7.
On the other hand, this spacing 17 should also not be less than 0.5 mm, preferably greater than 0.6 mm, 0.7 mm, 0.8 mm, 0.9 mm, or equal to or greater than 1 mm. Values about 1.5 mm, i.e. generally between 1 mm and 2 mm or 1 mm and 3 mm, 4 mm or 5 mm are entirely sufficient.
On the other hand, it should also be noted that the height or thickness 14 of the three-dimensional patch element 13 is preferably less than the height or thickness 15 of the dielectric carrier 5. The uppermost patch element 13 preferably has a thickness or height 14 corresponding to less than 90%, in particular less than 80%, 70%, 60%, 50% or even less than 40% and optionally 30% or less than 20% of the height or thickness 15 of the carrier element 5.
On the other hand, the abovementioned height does not necessarily have to be prerestricted. The height or thickness 14 of the three-dimensional patch element 13 may also therefore be greater, and above all significantly greater, than the thickness of the dielectric carrier 5. In other words, the carrier element 5 may, for example, have a height or thickness 15 corresponding to up to 1.5 times, twice, four, five, six, seven, eight, nine and/or ten and more times the height or thickness 15 of the carrier element 5.
On the other hand, the thickness or height 14 of the patch element 13 should preferably be greater than the distance 17 between the radiation face 7 and the lower side 13b of the patch element 13.
A carrying means 19, in particular a dielectric carrying means 19, via which the patch element 13 is held and carried, is preferably used. This dielectric carrying means 19 preferably consists of an adhesion or mounting layer 19′ (
However, instead of the electrically fully conductive metallic member as the patch element 13, a plastics material member, which is provided, for example, with an electrically conductive lower side 13b and electrically conductive peripheral lateral boundaries 13c, may, for example, also be used, for example by applying an electrically conductive outer layer. The upper side 13d does not necessarily have to be electrically conductive, although the entire surface of the patch element 13 thus formed, which is per se non-conductive, may be provided with a peripheral electrically conductive layer.
A patch element 13 of this type may, for example, be made from a metal sheet by punching and edging as illustrated, for example, in plan view in
In this case, too, the lower side 13b of the patch element 13 thus formed is fastened to the upper side of a, for example conventional commercial, patch antenna A using a carrying means, for example using a layered dielectric carrying means 19, preferably in the form of an adhesion or mounting carrier 19′, wherein a conventional commercial patch antenna A may also, but does not have to, be coated with a dielectric layer on the upper side of its radiation face 7.
a shows in schematic cross section and
Similar advantages may also be achieved according to a configuration corresponding to
Finally,
Finally, it should also be noted that on use of a volume member, too—comparable, for example, to the exemplary illustrative non-limiting implementation according to
The exemplary illustrative non-limiting stacked patch antenna may preferably be used as an antenna within the context of a motor vehicle antenna, in addition to further antennas for other services. However, this does not entail any limitation to such uses. The conventional commercial patch antenna A used within the context of this exemplary stacked patch antenna preferably consists—as stated—of a dielectric carrier 5, the upper or lower side of which consists of a metallic or electrically conductive layer 7 or 3 and is fixed to the carrier 5.
Finally, reference is also made to
While the technology herein has been described in connection with exemplary illustrative non-limiting implementations, the invention is not to be limited by the disclosure. The invention is intended to be defined by the claims and to cover all corresponding and equivalent arrangements whether or not specifically disclosed herein.
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