WO2012110215A1

WO2012110215A1 - Patch antenna and method for tuning the frequency of such a patch antenna

Info

Publication number: WO2012110215A1
Application number: PCT/EP2012/000588
Authority: WO
Inventors: Sandra KNÖRZER; Thomas Lankes; Gerald Schillmeier
Original assignee: Kathrein-Werke Kg
Priority date: 2011-02-17
Filing date: 2012-02-09
Publication date: 2012-08-23
Also published as: EP2676326A1; DE102011011494A1; EP2676326B1

Abstract

The invention relates to an improved patch antenna characterized by the following features: at least one slit arrangement (15) is provided at at least one edge segment (13c) in the circumferential direction and preferably at at least two and in particular four edge segments (13c) of the emitter surface (7) offset in the circumferential direction, wherein said arrangement extends from the associated edge segment (13c); the slit arrangement (15) comprises at least one closed slit cut-out (115; 115a, 115b,…,115f) in the slit direction (15') facing away from the associated edge segment (13c); and the at least one closed slit cut-out (115; 115a, 115b,…,115f) is closed by an electrically conductive transverse or tuning bar (17) facing toward the associated edge segment (13c).

Description

Patch antenna and frequency tuning method of such a patch antenna

The invention relates to a patch antenna according to the preamble of claim 1 and to a method for frequency tuning of such a patch antenna according to the preamble of claim 17.

Patch antennas or so-called microstrip antennas are well known. They usually comprise an electrically conductive base area, a dielectric carrier material arranged above them and an electrically conductive radiation area provided on the upper side of the dielectric carrier material. The upper radiation surface is usually excited by a transverse to the above-mentioned planes and layers feed line. In particular, a coaxial cable whose outer conductor is electrically connected at one connection to the ground conductor is used as connection cable, whereas the inner conductor of the coaxial cable is electrically connected to the overhead radiation surface. Other forms of feeding, such as aperture coupling, are also known and applicable. Today, it is often desirable to manufacture patch antennas with a substrate, which is made of ceramic, for example. In the production of high-permeability ceramic materials with ε _Γ , however, there is the problem that in the composition of the ceramic material and the firing of the substrate, the permittivity of the ceramic for different reasons, for example, for reasons of material composition, the injection pressure, the sintering temperature, etc. can vary. Especially with high-permeability ceramic patch antennas with a ceramic substrate with ε _Γ > 20, fluctuations of + 1, ie fluctuations of up to 5%, can occur. This ultimately leads to a deviation of the resonance frequency. Therefore, as part of a series production of such a patch antenna usually manual post-processing for frequency tuning of the antenna is necessary.

For this reason, it has already been proposed to rework patch antennas, which are supplied in particular via a feed point, in that, for example, the corners are bevelled at two opposite corners of the active radiator surface, for example by manual milling. In addition, in the case of a patch having one or more feed points, it has already been proposed to mill slots running inward from the side edges of the patch into the material of the radiator surface.

The resulting frequency tuning is done by hand on Net zwerkanalysator. In this case, however, the axis ratio, the opening angle and other recognition variables are not measurable. The radiation properties of the antenna therefore vary over different patterns. It is therefore an object of the present invention to provide an improved patch antenna with an already prepared Nachbereitungsmöglichkeit for frequency tuning, and an improved method for such frequency tuning.

The object is achieved with respect to the patch antenna according to the in claim 1 and with respect to the Frequenzabstimm method according to the features indicated in claim 17. Advantageous embodiments of the invention are specified in the subclaims.

In the context of the invention, a quite surprising solution is created, which makes it possible to carry out a corresponding post-processing for frequency tuning of a patch antenna according to the invention with simple means.

The invention is based on the basic idea that, starting at the edge of the patch antenna, slits are made running inwardly in the material of the area radiator, but these are virtually "closed" via transversely extending, electrically conductive webs. In this case, at least one recess is provided in the context of the invention of the relevant side edge of the patch antenna from inwardly extending, which is completed via at least one transverse web extending to the side edge or at the edge of the patch antenna. The relatively small-sized recesses thus have virtually no influence on the radiation characteristic of such a patch antenna. In other words, such a patch antenna is comparable to a patch antenna without such recesses. In order to carry out a post-processing for frequency tuning, the respective webs can be removed from outside to inside as needed. If a plurality of closed recesses are provided one behind the other, which are separated from each other by a plurality of conductive webs, then a plurality of webs can also be removed stepwise from outside to inside. The more webs are removed from the slots, the deeper the resonant frequency of the antenna becomes.

The fact that only the individual webs must be separated, a post-processing by hand and / or machine can be easily performed. For the dimensioning of the webs thus formed, in particular their size in the longitudinal direction, is virtually predetermined and defined in sections of the pre-inserted recesses.

This results from the inventive antenna a simple way of tuning the frequency.

The tuning option according to the invention and the tuning method according to the invention are suitable for patch antennas with one, two or more feed points. For a circularly polarized antenna, the antenna according to the invention also makes it possible to tune the axis ratio (AR) by means of a virtually independent tuning of the two linear polarizations. In the context of the invention, the spacings of the webs in the longitudinal direction of the slot formation can be equidistant. As a result, the length of the individual recesses is perpendicular to the respective boundary edge, ie to the edge portion of the surface radiating element running the same length. But it is also possible that these distances are designed differently. Preferably, the distances of the individual webs from the inside outwards to the longitudinal or transverse boundary edge of the surface radiator with a square spacing increase. The Abstimmstege are in their dimensions, as the individual recesses between the Abstimmstegen, relatively small compared to the wavelength at which the patch antenna in question is to be operated. This applies in particular even if the relevant patch antenna is to be used, for example, as an RFID antenna.

The invention can preferably be realized with a square patch antenna in plan view. In principle, however, the patch antenna can also have any other outline shapes, for example formed with an n-polygonal structure. Likewise, however, a patch antenna with non-straight boundary edges is also possible, in particular in the form of a circular patch. In principle, there are no restrictions.

The solution according to the invention offers a number of advantages over the prior art.

Above all, the patch antenna according to the invention is characterized in that due to the geometry with one or the plurality of webs for each of the slot arrangements, a manual or machine-defined step-by-step tuning is possible without problems.

Due to the simplified processing, an optimized antenna behavior and a cost reduction in the tuning process can be achieved. The tuning method according to the invention is also relatively insensitive to the accuracy of the milling.

Furthermore, the solution according to the invention, i. the patch antenna according to the invention also characterized in that the

Symmetry of the antenna structure is maintained even when performing the explained tuning method.

In addition, an independent tuning of the individual ports (supply points) to different resonance frequencies (individual tuning) is possible within the scope of the invention.

In principle, it is known to provide a patch antenna with slots running centrally from the side edges. This is known, for example, from the prior publication "Electronics Letters, Vol. 33, No. 22, 23rd October 1997". Background of such a patch antenna is to downsize a circularly polarized square patch patch antenna. The slots on the circumferential longitudinal or transverse edges increase the current path, which reduces the resonance frequency of the patch. If a further tuning has to be done manually here, then the slots would have to be manually increased in length with all the problems that adversely affect the electrical radiation properties of the antenna due to processing and tolerance errors.

The invention will be explained in more detail with reference to drawings. In detail:

FIG. 1 shows a schematic cross section through a patch antenna according to the invention; a plan view of a first embodiment of a patch antenna according to the invention in a schematic representation; a plan view of an opposite to Figure 2 modified embodiment; a plan view of a further modified embodiment; a further embodiment in a schematic plan view in deviation to Figure 2, wherein in each case at least two slot arrangements are provided on all sides of the radiator surface, which are offset in the longitudinal direction of the respective side boundary to each other; a further embodiment in a schematic plan view with a plurality of equidistantly arranged Abstimmstegen; a deviating from Figure 4 embodiment with a plurality of non-equidistant Abstimmstegen whose distance increases outwardly to the boundary edge of the surface radiator with a square spacing; a further modified embodiment with non-equidistant Abstimmstegen and outer closed ridge; Figure 7: a modified to Figure 6 embodiment with non-equidistant Abstimmstegen, but the outer webs are open; and

8 shows a modified embodiment using a circular in plan view patches.

FIG. 1 shows a schematic cross-sectional view of a patch antenna 1 with a ground surface 3 at the bottom, a substrate / dielectric 5 made thereon, for example made of ceramic, and a radiator surface 7 arranged on the top side 5a of the substrate 5. In other words is the ground surface 3 on the bottom 5b of the substrate. 5

The antenna can be fed via one, two or more supply lines 9, which usually leads via a bore hole 3 a lying below in the ground surface 3, a bore 5 c aligned therewith in the substrate / dielectric 5 up to the radiator surface 7 lying on top it is electrically-galvanically connected to a feed point 11. Using a feed line, a linearly or circularly polarized patch radiator and using at least two feed lines which terminate at two mutually offset feed points (mutually offset by 90 ° feed points), a dual polarized or circularly polarized patch radiator can be formed in a known manner. In the case of several feed lines, a plurality of bores corresponding to the variant shown in FIG. 1 are provided, through which a feed line 9 passes. Notwithstanding the above-described type of food 109 of the patch but also any other types of food 109 are possible and feasible and are not contrary to the present invention. Thus, notwithstanding the illustrated embodiments, the feeding of the emitter surface of the patch radiator, for example, not only by means of a coaxial cable (often called "sample feed"), but also by the following measures:

The feeding takes place e.g. In stripline technology (eg microstrip line, coplanar line or other forms), which are sometimes also known under the terms "microstrip line feed" or "edge feed" and in the case of an adapted feed line under the term "inset feed" or in the case of a missing Galvanic connection can also be called "Coupled Inset Feed".

The feed takes place in the form of a "proximity coupling", in which the feed line is located in a different substrate plane than the radiating element.

Also possible is a so-called "aperture coupling" in which the substrate plane of the feed line is separated from the radiator element by a metallic surface with an aperture.

Finally, a feed arrangement can also be realized in the form of a so-called "Stacked Coupling Feed", in which the emitter element is excited by being coupled by a feed element.

The above further examples are only for Clarification that the most varied feed structures are possible and permissible within the scope of the invention. Therefore, in the following, in part, only one or more feeders 109 for the patch or the emitter surface 7 will be discussed.

In the plan view according to FIG. 2, the peripheral edge region 5 'a is visible on the upper side 5 a of the substrate / dielectric 5. That is, the peripheral edge region 5'a projects laterally beyond the radiator surface 7. In the middle of the square-shaped substrate 5 shown in the embodiment shown, the square basic (or rectangular) formed radiator surface 7 is provided, with each parallel to each other, the oppositely arranged longitudinal sides 13a and 13b transverse sides. Generally speaking, the emitter surface 7 has a peripheral edge 13, which in the exemplary embodiment shown directly comprises two opposite parallel longitudinal sides 13a and two transverse sides 13b offset by 90 ° thereto. Notwithstanding the basically square-shaped patch in plan view, ie of the square in principle shaped radiator surface 7, this may also be formed, for example, rectangular or n-polygonal, preferably in the manner of a regular n-polygonal with the same side lengths. As will be shown later, however, other radiating surfaces with curved edges 13 can also be used, in particular in the form of a circular radiator surface 7. On each of the longitudinal and transverse sides 13a and 13b, one extends from an associated edge section 13c and inwards into the radiator surface 7 slit arrangement 15 extending in the embodiment shown. tion example to a perpendicular to the radiator surface 7 extending central axis Z aligned. In the exemplary embodiment shown, the central axis lies on the intersection of the diagonals through the corners of the emitter surface 7 formed quadratically in the exemplary embodiment.

However, the respective slot arrangement 15 is not incorporated as a continuous slot, but comprises in the illustrated embodiment according to Figure 2 at least one Schiitzausnehmung 115, that is in the present case a Schiitzausnehmung 115a, the edge 13, ie the respective longitudinal or transverse side 13a or 13b out, via a crosspiece 17 is completed. In extension of the closed ski recess 115a, an open slot recess 115 'then adjoins the crosspiece 17 towards the edge 13. In the exemplary embodiment shown, the mentioned transverse or tuning web 17 runs parallel to the respective associated longitudinal or transverse edge 13a, 13b, from which the respective slot arrangement 15 originates.

In the exemplary embodiment shown, therefore, the slot arrangements 15 run perpendicular to the respective edge section 13 or 13c from which the associated slot arrangement 15 originates, the directions of extension 15 'of this slot arrangement in the exemplary embodiment shown passing through the central axis Z which is aligned perpendicular to the radiator surface 7 is.

In other words, the electrically conductive transverse or tuning web 17 connects the two electrically conductive adjacent sections of the radiator surface 7. These Therefore, transverse webs 17 are part of the metallization surface 117, that is, a total of the radiator surface 7. The mentioned slot recesses 115 are produced from home by suitable methods, such as etching, mechanical milling, etc. In other words, the mentioned transverse or Abstimmstege 17 no separate, subsequently applied to the radiator surface 7 electrically conductive parts, but are part of a uniformly formed radiating surface 7, usually in the form of a metallization layer or surface 117th

The slot arrangement 15 can in principle extend obliquely from the associated longitudinal or transverse side 13a, 13b, ie at an angle which deviates from a 90 ° angle to the extension direction of the longitudinal or transverse side 13a, 13b, ie from a right angle to associated edge portion 13c deviates, in the area of the slot assembly 15 begins. For example, in the case of a patch radiator in circular form, the slot assembly 15 may extend at an angle less than or greater than 90 ° with respect to a tangent that contacts the circular rim 13 or edge portion 13c from which the slot assembly 15 extends. In this case, therefore, the extensions of the slot arrangements (ie, the axis in which the slot arrangement 15 is formed) would not intersect the central axis Z, but would run past it at an oblique angle. In the exemplary embodiment shown, however, the respective slot arrangement 15 is oriented at right angles to the respectively associated longitudinal and transverse sides 13a, 13b and thus to the associated edge 13 or associated edge section 13c, from which the respective slot arrangement 15 runs. In the exemplary embodiment shown, the respective slot arrangement 15 has Weil two lateral slot boundaries 19, which are also parallel to each other at a distance. The conductive transverse webs 17 provided in this slot arrangement and the associated web edges 17a are also preferably aligned parallel to one another and preferably parallel to the respectively associated longitudinal and transverse edges 13a, 13b and thus respectively to the associated edge section 13c from which the relevant slot arrangement 15 goes out.

Already at this point, reference is made to the later explained embodiment according to FIG 8, that instead of the aforementioned longitudinal and transverse edges 13a and 13b is generally spoken of the edge 13 or the associated edge portion 13c, of which the respective slot assembly 15 in the radiator surface 7 is formed extending into it. In that regard, so in part instead of longitudinal and transverse sides 13a and 13b from the edge 13 or edge portion 13c spoken, as shown in particular with reference to the later discussed embodiment of Figure 8 that also emitter surfaces can be used, not an n Polygonal shape, in particular so are not square, but for example, curvy and are designed in particular circular.

In the exemplary embodiment according to FIG. 2, a slot recess 115 closed by a transverse or tuning web 17 is therefore provided for each slot arrangement 15. In this embodiment, the first or the edge 13 closest lying and closed by a transverse web 17 slot recess is formed by the slot recess 115a. As can also be seen from Figure 2, runs the transverse web 17 with its central axis Z remote edge side 17a not in extension of the adjacent edge portion 13c, ie the longitudinal or transverse side 13a and 13b, but is in the slot direction 15 'of the associated edge 13 or edge portion 13c, ie the associated longitudinal - or transverse side 13a, 13b arranged offset inwardly, so that adjoins the respective closed slot recess 115a to the associated edge 13 through an open slot recess 115 '. In this exemplary embodiment, therefore, the slot recess 115 'lying too far is open, and is therefore not closed by any transverse web 17 extending in the amount of the respective longitudinal and transverse edges 13a, 13b. However, as is also shown below by way of example with reference to a further exemplary embodiment with reference to FIGS. 4 or 5, the open slot recess 115 'according to FIG. 2 in the region of the edge 13 can be dispensed with, so that then the closed slot recess 115a acts as the first slot recess adjoins the associated edge or edge portion 13c, in which the outer edge 17a of the transverse web 17, for example, in the immediate extension of the edge 13 or the edge portion 13c, ie in the immediate extension of the respective longitudinal or transverse edge 13a, 13b runs.

The respective web length 21, which also corresponds to the slot width 21 in the embodiment shown, can be chosen differently, which will be discussed later. The web width 23 may vary in their dimensions.

The same also applies to the length 25 of the respective slot recess 115, which are chosen differently can. In the embodiment shown, the recess length 25 for the outer first open slot recess 115, 115 'is just as long as for the subsequent inner Schiit zausnehmung 115, 115 a, where, as mentioned, the relevant Schiitzausnehmungen 115', 115 a each Slot arrangement 15 of the respective longitudinal or transverse edge 13a, 13b, starting in the slot direction 15 'are behind each other. Furthermore, in the exemplary embodiment shown, the respective slot recess 15 is provided on each of the four outer edges 13a, 13b, preferably in the middle of the respective longitudinal and transverse edges 13a, 13b. Hereinafter, a modification with reference to Figure 2a and Figure 2b will be discussed.

FIG. 2a shows a patch antenna with a basically similar construction as explained with reference to FIG. 2, but only with two opposite slot arrangements 15 (and not with a total of four slot arrangements as in FIG. 2).

Another difference from FIG. 2 is that, in the variant according to FIG. 2 a, a first closed slot recess 115 a is located at the immediate edge 13, that is to say at the one shown here, one longitudinal slot 13 a and subsequently separated by a further slot 17. a next closed slot recess 115b connects. In other words, the edge recess 13 closest to the slot recess 115a is closed by an outer slot 17 whose outer slot edge 17a is aligned with the peripheral edge 13, So part of the peripheral edge 13 of the electrically conductive metallization 117 is.

In addition, the respective slot length 25 is different in the two successive Schiit zausnehmungen 115 a and 115 b, wherein the outer slot 115 a is longer, in the illustrated embodiment, approximately twice as long as the inward toward the central axis Z subsequent slot recess 115 b.

In the exemplary embodiment according to FIG. 2 b, a slot arrangement 15 is again provided on each of the four longitudinal or transverse sides, namely in each case once again only a single slot recess 115 a, whose transverse or withdrawal web 17 is again provided on the outside as in FIG the outer boundary edge 17a of the web 17 is aligned with the edge 13 of the patch surface 7.

It is shown with reference to FIG. 3 that, for example, at each of the four outer edges 13a, 13b, two shallow recesses 15 which are offset in the longitudinal direction of the respective longitudinal and transverse edges 13a, 13b can be provided. Basically, three, four or a maximum of five Schiitzausnehmungen 15 may be provided on each side, each extending from the associated longitudinal and transverse edges 13a, 13b and preferably arranged parallel to each other and thereby offset in the longitudinal direction of the respective longitudinal and transverse edge to each other ( preferably at equal intervals or at different distances from each other).

In contrast to the embodiment according to Figures 2 and 3 can be achieved by the use of several Slot arrangements per side carry out a vote over a larger frequency range.

Referring to Figure 4, it is shown that the respective slot assembly 15 may include a plurality of individual closed slot recesses 115. In the variant according to FIG. 4, starting from the respective longitudinal and transverse sides 13a, 13b, six shafts each separated by a transverse web 17 and thereby closed are arranged in succession. In other words, the Schiit zausnehmungen 115 are each surrounded by the radiator surface 7, said transverse webs 17 represent cable bridges that connect the corresponding portions of the radiator surface 7 on both sides of the respective slot assembly 15 and at the same time the individual Schiit zausnehmungen 115 separate from each other, so that thereby the so-called closed Schiit zausnehmungen 115 are formed. In this embodiment, therefore, slot recesses 115a, 115b, 115c, 115d, 115e and 115f are provided. The ridge width 21 and the recess length 25 is always the same in this embodiment, so that all slot recesses 115 have the same size and shape. In other words, this results in an equidistant arrangement of the electrically conductive transverse or tuning webs 17th

The exemplary embodiment according to FIG. 4 also differs from the one according to FIGS. 2 and 3 in that the slot recess 115a located at the outermost edge is also bordered by an outside at the level of the respective edge 13, ie the respective edge portion 13c, ie at the level of the respective longitudinal and transverse edge 13a , 13b arranged transverse or Ab- 17 is closed, so thus the edge 13 and thus the associated edge portion 13c, ie the respective longitudinal and transverse edge 13a, 13b runs continuously, as can be seen from Figure 4. A Schiitzausnehmung 115 'open to the associated edge 13 is thus not provided in this embodiment.

In contrast to FIG. 4, FIG. 5 shows that the individual ski recesses 115 can also have different lengths.

In the variant according to FIG. 5, the recess length 25 changes in the slot direction 15 '. In this case, the recess length 25 of the innermost, closed Schiitzausnehmung 115, here 115 d, to the outermost lying Schiit zausnehmung 115 a respectively. In other words, the distances of the transverse or Abstimmstege 17 from inside to outside with a square distance to each other. As a result, a non-equidistant arrangement of the individual tuning webs 17 is generated. Also in this variant, no overlying, open slot recess 115 'is provided. However, the above-mentioned distances of the transverse or Abstimmstege 17, which are arranged from outside to inside in a square distance from each other, but only a preferred special case. Basically, any other distances are possible, which are not or partially not equidistant.

In the variant according to FIG. 6, it is shown that a tuning possibility, which will be discussed below, already exists even if only two closed slot recesses 115a and 115b are provided, each with two transverse or tuning bars 17, as shown in FIG. indicates. In this case, the electrically conductive transverse and tuning web 17 of the slot recess 115a which is extremely located lies at the level of the peripheral edge 13, ie its outer edge 17a lies in the immediate extension of the edge 13 delimiting the radiator surface 7, ie in the immediate extension of the respective longitudinal edge. or transverse side 13a, 13b and thus of the associated edge portion 13c from which the slot arrangement 15 originates. Notwithstanding Figure 6 but could for example be dispensed with, for example, the second slot recess 115b, so that each slot assembly 15 only a closed slot recess 115, ie 115a includes, which is closed by the outside, provided at the level of the edge 13 transverse and Abstimmsteg 17 , as shown for example in FIG. 2a.

It is also possible, however, for not only at least one closed slot recess 115a to be provided towards the edge 13, that is to say on the longitudinal or transverse side, which is closed by the mentioned electrically conductive transverse or tuning web 17, but rather to the edge 13 still outwardly open slot recess 115 'connects, as shown in principle in the variant of Figure 7. In this embodiment, therefore, only one closed slot recess 115 a with an associated electrically conductive transverse and / or tuning web 17 is provided for each slot arrangement 15.

In the following, reference is made to FIG. 8, in which, in deviation from the preceding exemplary embodiments, a patch antenna in a central plan view, ie at least one emitter surface 7, for example in the form of a metallized surface 117 is shown, which consists of a circular shape in plan view.

In this case, the slot recesses 115, here 115a to 115c, are provided offset by 90 ° relative to one another about the central axis Z, which can be formed with respect to their slot length 25 or in their slot or web width 21, as this was explained with reference to the preceding embodiments. In the embodiment shown, therefore, the edge-side electrically conductive transverse or Abstimmsteg 17 is arranged at the level of the peripheral edge 13, so that its outer boundary edge 17a is designed partially circular with a radius around the center or the central axis Z of the circular radiator surface 7, so that a total circular edge 13 results. By way of derogation, however, as shown, for example, with reference to FIG. the first closed slot recess 115a lying closest to the edge 13 lie so far inwardly in the emitter surface 7 that a slot recess 115 'open to the outside in the radial extension remains on the electrically conductive transverse or tuning web 17 which is too far away. can connect, as shown in a modification for the slot arrangement 15 on the right in FIG.

Likewise, in each case two or more juxtaposed radiator arrangements could be provided, ie pairwise or parallel arrangements with a plurality of juxtaposed rows of radiator recesses 115, as shown in principle with reference to Figure 3 for a rather square in plan view radiator surface 7. In the variant according to Figure 8 thereby extend the gegebe ^¬ appropriate, several Strahlerausnehmungen of the emitter surface 13c preferably so that the extension of the slot arrangements 15 cut 115 comprehensive slot arrangements 15 7 surrounding and delimiting edge in radial direction, respectively, the central axis Z of the emitter surface 7 would. However, as has already been explained with reference to the further exemplary embodiments, the respective extension of the slot arrangement 15 can also run obliquely past the central axis Z of the radiator surface 7, in which case the slot arrangements 15 would not run in the radial direction to the central axis Z and thus not perpendicular to a tangent would terminate at the associated edge portion 13d from which the respective slot arrangement 15 originates (wherein in FIG. 8 a tangent T is shown for the slot arrangement 15 at the bottom), but at an angle deviating from 90 ° with respect to this tangent T. Von Therefore, also with regard to the embodiments explained above, the term generally refers to the edge 13 or the associated edge section 13c from which the respective slot arrangement 15 originates. If such a patch antenna in particular be implemented as an RFID antenna in a compact design, ie with a substrate or dielectric 5 with ε _Γ , for example ε _Γ > 10 and especially> 15 or especially>20,> 25 or> 30 or even> 35, it has been found that in the production of the substrate due to variations in the material composition of the substrate, ie in particular the ceramic starting material, the Verpressdru- and / or the sintering temperature Permittivitätszahl can vary considerably. Therefore, every single patch antenna has to be tested and a frequency tuning has to be carried out as part of a post-processing. This can now be easily done within the scope of the invention that depending on the measurement result from the outside inwards, each electrically-conductive transverse or tuning web 17 manually or electrically separated by means of tools, that is more or less removed.

If the respective outermost Schiit zausnehmung 115, as in the embodiment of Figures 5 or 6, closed by an outermost transverse or Abstimmsteg, this would be the first Schiit zausnehmung 115 a are opened, whereby the resonance frequency is slightly lowered. Should this not be enough, a next subsequent conductive transverse or Abstimmsteg can be severed, so that, for example, in the variant of Figure 5 or 6, a further inner next cross or Abstimmsteg 17 is severed, whereby the free overall length of the open slot arrangement thus formed 115 'enlarged in the slot direction 15' and thus the resonance frequency of the patch antenna is further lowered.

Due to the geometry with the mentioned electrically conductive transverse or Abstimmstegen 17 thus a trouble-free manual or machine defined gradual tuning is possible because the slot lengths zausnehmungen by the given Schiit given clearly and reproducibly, creating a manual incorporation of slots relative to the state of Technology is easily possible and mismatches (as usual in the art and hardly prevent) omitted. In addition, even a machine cutting through a web is easily possible, and also to produce a clearly defined slot length due to the given individual Schiitzausnehmungen.

The inventively embodied patch antenna and the tuning method of the patch antenna according to the invention has great advantages especially when a corresponding patch antenna in use for RFID systems, for example, with an operating frequency between 800 MHz and 1000 MHz to be operated. In this case, the method is suitable for dielectrics of the most varied composition of materials and with very different permittivity numbers, in particular for patch antennas with a substrate / dielectric which, for example, has a dielectric constant for ceramics between 20 to 80, in particular 30 to 50 or for example 35 to 40, e.g. at 38.

With such a construction, a tuning range results through the individual slot arrangements up to more than 30 MHz, in particular up to more than 20 MHz and more than 10 MHz and more than 5 MHz, but at least up to 5 MHz.

The width 21 of the individual slot recesses (in each case parallel to the associated edge section) can be, for example, between 0.3% to 27%, in particular between 0.7% to 15%, 1% to 2.6% and in particular by 1.0% to 2 %, for example, by 1.4% based on the wavelength in the substrate, and with respect to an operating wavelength or preferably to the average operating wavelength in the substrate.

The slot length, ie the recess length 25 for each Schlit zausnehmung 15 (ie the so-called slot depth) can be between 0.8% to 25%, in particular between 1.7% to 10%, 2.6% to 5% and in particular by 3.9%, and also again relative to an operating wavelength or preferably to the average operating wavelength in the substrate.

Finally, it should be noted that the width of the transverse or tuning webs (17) between 0.1% to 18%, in particular between 0.1% to 5% and in particular between 0.1% to 1.8% based on an operating wavelength and in particular the average operating wavelength in the substrate 5 may be preferred.

Based on the described embodiments is also shown that the length, that is, the total length of a slot assembly 15, starting from the edge 13 with a first open Schiit zausnehmung 115 'or without such an open Schiit zausnehmung 115' may be different. The maximum length of the entire respective slot arrangement 15 can be between 0.8% and 25%, in particular between 1.7% to 10%, 2.6% to 5% and in particular about 3.9% based on an operating wavelength and preferably on the average operating wavelength in the substrate (5) lie.

As already mentioned, the individual slot arrangements 15 are preferably each centered with respect to the associated edge section of the patch surface or the associated metallization, that is to say the radiator surface 7. However, these slot arrangements 15 can also deviate from their central position, preferably up to 5%, 10%, 15%, 20%, or preferably up to 25%, 30%, 35% or maximum up to 40%. In other words, the individual slot recesses can be arranged within a range of at most 10% to 90% of the total length of the longitudinal and transverse sides 13a, 13b. With regard to the circular design of the patch according to FIG. 8, this means that with respect to a regular arrangement of the slot recesses offset by 90 ° (as shown in FIG. 8), a deviation of up to + 40% relative to a quarter circle circumference can and may be made.

It has been explained in the various embodiments that the number of slot arrangements 15 can vary as a whole. In most embodiments, each four offset by 90 ° Schiitzausnehmungen are shown. Based on the embodiment of Figure 2a is shown that, for example, only two slot recesses may be provided, arranged opposite in this embodiment. With reference to FIG. 3, it is shown that a plurality of ski recesses can be provided. In principle, however, the advantages according to the invention are also realized if at least one slot recess 15 is provided at a single point relative to the entire peripheral edge 13.

In all of the embodiments shown, the slot recesses 115 and the slot recesses 115 laterally delimiting slot boundaries 19 are aligned parallel to each other and each perpendicular to the adjacent longitudinal and transverse edge. But even here, angle deviations of up to 20% are possible. Angular deviations of up to 20% are also possible with respect to the transverse or tuning webs 17, which need not necessarily run parallel to the adjacent longitudinal and transverse edges.

Claims

Claims:

1. patch antenna, in particular RFID patch antenna with the following features:

with a substrate (5) having an upper side (5a) and a lower side (5b),

with an electrically conductive radiating surface (7) provided on the upper side (5a) of the substrate (5),

with at least one, two or more feed devices (109), for feeding the radiator surface (7), and at least one peripheral edge portion (13c) and preferably at least two and in particular four circumferentially offset edge portions (13c) of the radiator surface (13c) 7), at least one slot arrangement (15) originating from the respective edge section (13c) is provided,

characterized by the following further features: - the slot arrangement (15) has at least one closed ski recess (115; 115a, 115b, 115f) in the slot direction (15 ') pointing away from the associated edge section (13c), and

the at least one closed slot recess (115; 115a, 115b, 115f) is closed via an electrical-conductive transverse or tuning web (17) facing the associated edge section (13c).

2. patch antenna according to claim 1, characterized in that between the at least one closed slot recess (115; 115a, 115b, 115f) and / or the associated edge portion (13c) closest to the closed slot recess (115; 115a) and the associated edge portion (13c) is an open slot recess (115 *) is provided, which is open to the associated edge portion (13c).

3. patch antenna according to claim 1, characterized in that the at least one closed slot recess (115; 115a) and / or the associated edge portion (13) closest closed Schlitzausnehmung (115; 115a) by an electrically conductive transverse or Abstimmsteg (17) is closed, the outwardly facing web edge (17a) in the immediate extension of the adjacent edge (13) or edge portion (13c) of the radiator surface (7) is arranged.

4. patch antenna according to one of claims 1 to 3, characterized in that a plurality of closed slot recesses (115; 115a, 115b, 115f) are provided, which are arranged ^one behind the other in the respective slot direction (15 ¹ ), wherein two adjacent each closed slot recesses (15; 15a, 15b,

15f) are separated by an electrically conductive transverse or Abstimmsteg (17).

5. patch antenna according to one of claims 1 to 4, characterized in that the respective lengths (25) belonging to a slot arrangement (15) closed slot recesses (115; 115a, 115b, 115f) are equal.

6. Patch antenna according to one of claims 1 to 4, characterized in that the respective lengths (25) of a slot arrangement (15) belonging to the closed slot recesses (115; 115a, 115b, 115f) are of different sizes.

7. patch antenna according to claim 6, characterized in that the respective lengths (25) of the Schiitzanord- tion (15) belonging to several closed slot recesses (115; 115a, 115b, 115f) are different in size and in particular from the inside to the outside to the edge (13) of the radiator surface (7) or to the associated edge portion (13c) increase quadratically.

8. patch antenna according to one of claims 1 to 7, characterized in that at least two edge portions (13c) a slot arrangement (15) is provided, preferably at 90 ° offset to each other edge portions (13c), and that in particular in a square or rectangular radiator surface (7) on at least two opposite longitudinal or transverse sides (13a, 13b) and preferably on all longitudinal or transverse sides (13a, 13b) Schiitzanordung (15) is provided.

9. Patch antenna according to one of claims 1 to 8, characterized in that of a longitudinal or transverse side (13 a, 13 b) or by an edge portion (13 c) and preferably Starting from all longitudinal or transverse sides (13a, 13b) or from a plurality of edge portions (13c), at least one, two, three, four or a maximum of five slot arrangements (15) are provided which are offset relative to each other in the extension direction of the associated edge portion (13c) are.

10. patch antenna according to one of claims 1 to 9, characterized in that the respective Schiitzausnehmung (15) and / or the lateral slot boundary (19) perpendicular to the adjacent longitudinal or transverse side (13a, 13b) or perpendicular to the adjacent edge portion ( 13c) from which the Schiitzausnehmung (15) starts, is aligned and not more than 20 ° thereof deviates.

11. patch antenna according to one of claims 1 to 10, characterized in that the electrically conductive transverse or Abstimmstege (17) parallel to the longitudinal or transverse sides (13 a, 13 b) or parallel to the adjacent edge portion (13 c) of the radiator surface ( 7) are aligned, from which the respective slot recess (15) goes out, or not more than 20 ° thereof.

12. patch antenna according to one of claims 1 to 11, character- ized in that the slot width (21) and thus the web length (21) of a slot arrangement (15) or a single slot recess (115; 115a, 115b, ...) between 0.3% to 27%, in particular between 0.7% to 15% and in particular between 1% to 2.6%, for example by 1.4% based on the operating wavelength and in particular an average operating wavelength in the substrate (5).

13. patch antenna according to one of claims 1 to 12, da- characterized in that the depth or length of a Schiitzausnehmung (115; 115a, 115b, ...) in the slot direction (15 ') between 0.8% to 25%, in particular between 1.7% and 10% and preferably between 2, 6% and 5% based on an operating wavelength and in particular an average operating wavelength in the substrate (5).

14. patch antenna according to one of claims 1 to 13, characterized in that the width of the at least one transverse or Abstimmstegs (17) in the slot direction (15 ') between 0.1% to 18%, in particular between 0.1% to 5 % and preferably between 0.1% to 1.8% based on an operating wavelength and in particular an average operating wavelength in the substrate (5).

15. patch antenna according to one of claims 1 to 14, characterized in that the total recess length of a slot recess (15) <25%, in particular 15% or ^ 10% based on an operating wavelength and in particular a mean operating wavelength in the substrate (5) is.

16. patch antenna according to one of claims 1 to 15, characterized in that one or more Schiitzanord- openings (15) to the associated longitudinal or transverse side (13a, 13b) are arranged centrally starting, or preferably less than 5%, in particular less than 10%, 15%, 20%, 25% and a maximum of less than 40% relative to the edge length of the associated edge portion (13c) are arranged offset lying.

17. Tuning method for the subsequent frequency tuning of a patch antenna according to one of claims 1 to 16, characterized characterized in that with respect to one or more Schiitzausnehmungen (15) at least one of the associated edge portion (13c) nearest transverse or Abstimmsteg (17) is severed and / or removed.

18. Tuning method according to claim 17, characterized in that with respect to a Schiit zausnehmung (15) at least two or more transverse or Abstimmstege (17) severed and / or removed and in each case to the associated edge portion (13c) nearest Queroder Abstimmstege (17 ).

19. Tuning method according to claim 17 or 18, characterized in that the severing and / or removal of the transverse or Abstimmstege (17) is carried out manually and / or by machine.

20. Tuning method according to one of claims 17 to 19, characterized in that the severing and / or removal of the transverse or Abstimmstege (17) symmetrically on all two or four longitudinal or transverse sides (13 a, 13 b) or at the associated edge portions ( 13c) of the radiator surface (7) takes place.

21. Tuning method according to one of claims 18 to 20, characterized in that the severing and / or removal of the transverse or Abstimmstege (17) asymmetrically on all two or four longitudinal or transverse sides (13 a, 13 b) or on the associated wall sections ( 13a) of the radiator surface (7).