EP2137792A2

EP2137792A2 - Rfid antenna system

Info

Publication number: EP2137792A2
Application number: EP08735282A
Authority: EP
Inventors: Gerald Schillmeier; Frank Mierke; Thomas Lankes
Original assignee: Kathrein Werke KG
Current assignee: Kathrein SE
Priority date: 2007-04-17
Filing date: 2008-04-16
Publication date: 2009-12-30
Also published as: RU2009142219A; CA2683799A1; BRPI0810657A2; CN101657937A; WO2008125346A3; DE102007018058A1; WO2008125346A2; JP2010527521A

Abstract

The invention relates to an improved RFID-antenna-system for a goods identification system (WIS), said RFID antenna system being characterised by the following characteristics: the at least two patch antennas (21) form a group of patch antennas (A, B) for grouping and for reducing the size of the monitoring area in the direction of the passage (3') and the at least two patch antennas (21) are arranged at the same distance in relation to the surface of the base (5) of the path of the passage (3) and/or on the same horizontal plane or are offset in relation thereto, such that a straight line passes through the centre and/or centre of gravity of at least two adjacent patch antennas (21) formed with the horizontal plane and/or a plane that is parallel to the surface of the base (5) at an angle a that is = 45°.

Description

RFID antenna system

The invention relates to an RFID antenna system with an RFID antenna device for a goods identification system (WIS) according to the preamble of claim 1.

So-called UHF RFID methods and systems for article acquisition and identification (WIS) have already become known. In this case, a product to be detected is provided with an RFID tag. This method offers over a likewise known method for electronic article security (a so-called EAS system) first of all the significant advantage that not only a single bit can be evaluated as information by means of an RFID tag, but that this UFH RFID Labels are provided with a microchip on which information with a word length of several digits can be stored and read out by them. Preferably, so-called passive RFID tags are used, which use their energy to read the tag content and send back the corresponding information from the electromagnetic field of the antenna system. received. The RFID tag consists of an antenna structure with the aforementioned microchip. To read the information is - as is known - a so-called. Reader is used, for example, the tags the necessary energy for operation through the electromagnetic field is supplied via an antenna system, the provided with the microchip tags then the stored information using this Energy can send a corresponding response that can be read and evaluated via an antenna system and a downstream RFID reader.

With regard to the construction of an RFID antenna system for an electronic article security system (EAS), reference is made, for example, to the prior publication WO99 / 30384 A1. With regard to the use of RFID antenna systems for reading data in greater bit length, reference is also made to the pre-publication "3 Fundamental Operating Principles" in RFID Handbook: Fundamentals and Applications in Contactless Smart Cards and Identification, Second Edition, US Pat. Klaus Finke Zeller, Copyright ^® 2003, John Wiley & Sons, Ltd., ISBN: 0-470-84402-7, Chapter 1.2, 1.3, referenced 2.3 to 2.5.4 and 3.1 to 3.1.2.

In addition, electronic article security systems (EAS) for securing goods, for example, at the output of department stores, shops, etc. have become known. These consist of RFID antenna systems, which are arranged at a distance from one another in the region of the exit or a passage and between which the passageway to be monitored is formed.

The corresponding products available in the shop and Goods are secured, for example, by means of an electronic goods security label. If the goods are properly paid, the sales person will remove the corresponding counterfeit label, so that the customer can easily go through the monitored exit passage with the goods.

If the goods are still taken in the secured state through the monitored Auslassweg, in the monitored area usually issued an audible warning, for example, to report that an attempt is made to take unpaid goods from the store.

These electronic article surveillance systems can be implemented on a different technical basis.

The aforementioned EAS systems operate in the manner of a 1-bit transponder in which the presence or absence of a particular tag in the monitoring and reading area can be detected.

From US 2006/0132312 Al, an antenna system is basically known, which can be installed in a passageway (doorway). For this purpose, different antenna systems can be used, namely, for example, a patch antennas existing RFID antenna system. Alternatively, so-called loop antennas or a so-called photonic band GAP antenna can be used.

The antennas described may, in addition to a passageway on an adjacent wall pointing in the front direction or in an actual door frame facing in the front direction or pointing backwards or else parallel to Passage direction extending in the actual archway be arranged radiating.

If patch antennas are used, several patch antennas can also be operated together, which are arranged one above the other in the vertical direction. In a further exemplary embodiment shown, a plurality of such patch antennas can be used, which are arranged to run in a plurality of branches in the vertical direction and operated together, wherein in a variant described so-called diversity switches or diversity combiners can be used for this purpose. However, it can not be deduced from this pre-publication that this system can be used for an electronic article security system EAS and / or for a goods identification system WIS. At least, this prepublication also does not reveal that an RFID antenna system can be constructed which comprises antennas for an electronic article security system EAS and, in addition, antennas for a goods identification system WIS.

The object of the present invention is therefore to provide an improved RFID antenna system for a goods identification system (WIS) for reading out tags provided with a microchip. It should be a fundamentally simple system. If necessary, the system should also be easily adaptable to different circumstances and peculiarities in order to obtain optimum results with regard to the retrieval of information from corresponding tags. In a preferred embodiment of the invention, it should also be ensured that the antenna system according to the invention also can be retrofitted in a conventional electronic article security system (EAS).

The object is achieved according to the invention in accordance with the features specified in claim 1. Advantageous embodiments of the invention are specified in the subclaims.

The inventive electronic goods identification system (WIS) is characterized on the one hand by the simple structure and its high flexibility and adaptability to different circumstances and specifics on site. At the same time, the monitoring and reading range can be adjusted so differently that malfunctions can be safely avoided.

The inventively improved system works, as in the prior art, based on the RFID technology.

In order to realize a simply constructed system with a high "hit rate" and high functional capability, the invention provides that the antenna system provided laterally by a passage area to be monitored comprises at least two antennas, these at least two antennas in the passage direction or at least with one component in the passage direction are arranged side by side. You do not necessarily have to be in the same altitude (ie, for example, parallel to the level of the passageway), but can also be partially positioned at different altitudes. However, a line lying through the middle or center of gravity of the two adjacent antenna systems should be opposite a horizontal plane (or a plane parallel to the passageway plane) have an angular deviation, which is preferably not greater than 45 °.

The UHF RFID system includes patch antennas or patch antennas. These have a particularly low overall height and can therefore be easily retrofitted into existing, often consisting of frame-shaped antennas EAS antenna system devices, for example, within the frame-shaped antenna of the existing EAS monitoring system.

The arrangement of two patch antennas, which are offset from each other with lateral offset in the passage direction or with a component in the passage direction, can be realized with simple means improved bundling of the surveillance area. This offers significant advantages insofar as correspondingly tagged goods or products are only detected and read out when a person with a product comprising a microchip comprising an RFID tag actually passes through the defined reading area (ie the surveillance area) and not only in passes near this reading area. This ensures, above all, that no too early detection is triggered by the fact that, for example, a person walks past the passage protected by two antenna systems at the side only in the immediate vicinity (for example still in the store) and thereby a product secured with a tag already reach the detection and / or reading range of the antenna system.

The patch antennas according to the invention can be used as individual Patch antennas be formed. However, they can also be designed as combined patch antennas, which are formed, for example, on a common ground plane, on a common substrate, etc., so that only the patch areas are arranged separately on this substrate. Here are any modifications possible.

In a particularly preferred embodiment of the invention, for example, at least two pairs of patch antennas are arranged one above the other at each side antenna device, ie at two different levels or planes (where the paired patch antennas, as mentioned above, are not necessarily the same Height level, but at least in the specified extent offset from each other can be arranged).

However, it is also possible that in the forward direction not only two but several antennas, for example three or more patch antennas, are used in order to reduce the bundling area and thus the narrowing of the monitored area in the direction of the passage to a narrow passage zone. In other words, there is thus a bundling of the antenna field and thus of the monitoring area in the horizontal plane (in the case of a horizontally extending passageway), so that a passage zone monitored by the antenna device is formed, which extends in the direction of the passageway 3 (generally in the horizontal direction ) extends only over the smallest possible extent.

In addition to the above-mentioned preferred variants Furthermore, it has proved to be advantageous, if appropriate, to use in the lower transition region from the lateral limiting devices accommodating the antenna systems to the ground area (and / or to the ceiling area) additional antenna devices, in particular patch antennas, also again in a preferably pairwise arrangement. namely in the forward direction offset from each other. Preferably, the at the transition region to the ground and / or in the transition region to a ceiling, the patch antennas may be mechanically pre-adjusted so that their main radiation direction is not aligned substantially parallel to the plane of the passageway (the bottom surface), but deviating from it with a vertically extending component. This makes it possible to align, for example, antenna systems that are very low with their main beam direction slightly upwards, and that very high antenna systems are aligned with their beam direction somewhat downwards. As a result, regardless of the positioning of the antennas, an optimization of the monitoring area can be carried out.

It is also possible, alternatively or additionally, to perform an electronic alignment and / or adjustment of the antennas in order to preselect the detection and / or reading range differently, at least to a certain extent, and thereby to optimize it. This can be achieved, for example, by a predetermined or possibly also adjustable phase offset between two patch antennas arranged one above the other.

Likewise, it is possible according to the invention, by a mechanical pre-adjustment and / or a feed of two in a phase offset, whereby the area to be monitored from a plane of symmetry between the two patch antennas out in one or the other direction of the passageway can be adjusted.

According to the invention, the patch antennas can operate linearly or circularly polarized. In particular, the circularly polarized operation of the patch antennas has advantages in so far as it is ensured that a product tagged with RFID tags is always reliably recognized and the information stored on the tag can be easily and completely read, regardless of the orientation of the tag when passing through the reading area.

This RFID system preferably operates in the UHF range, for example in the 800 MHz to 1000 MHz range (in particular in the 800 MHz to 950 MHz range - for example 868 MHz range). The reading range of the patch antennas can be up to 1.5 m and more (for example, up to 2 m, etc.).

In a preferred embodiment of the invention, it is further provided that the Waren-Identifcations-System (WIS) according to the invention and the associated

Antenna device also in an existing RFID antenna system for an electronic article surveillance system

(EAS) can be retrofitted without the

Functioning and operation of this EAS system or the goods identification system is adversely affected by the retrofitting.

Further advantages, details and features of the invention result from the embodiments described with reference to various figures. In detail:

Figure 1 is a schematic representation of a monitoring area or passage for an electronic goods identification system (WIS);

FIG. 2 shows a schematic view of the UHF antenna arrangement according to the invention for an electronic article security system (EAS) in the direction of the transit view;

FIG. 3 is a schematic plan view of a patch antenna pair used;

4 shows a corresponding cross-sectional view parallel to the passage direction on the reproduced in Figure 3 patch antenna

Pair;

FIG. 5 is a cross-sectional illustration of an embodiment modified from FIG. 3;

FIG. 6 shows an embodiment of a patch antenna pair deviating from FIGS. 3 and 4;

FIG. 7 shows a further modified exemplary embodiment in plan view of the patch antennas used; FIG. 8 shows a further detailed representation of a possible embodiment variant; and

FIG. 9 shows a simplified embodiment variant corresponding to FIG. 8.

1 shows the schematic basic structure of an electronic article identification system (WIS) is shown, with two mutually offset antennas neneinrichtungen 1, between which a passageway 3 along the passage direction is 3 ^■ on a bottom surface 5 therethrough.

The antenna devices 1 are formed in the manner of lateral boundaries I ¹ , which essentially comprise a vertical or vertical extension 7 extending transversely or in particular perpendicular to the bottom surface 5, a transverse or parallel or substantially parallel or with a component parallel to the passage 3 Horizontal straightening 9 and a comparatively narrow designed thickness extension 11 transversely or perpendicular to the passage direction 3 and thus in particular parallel to the bottom surface 5 have.

Between the relative to the passage 3 and the passage 3 'left or right arranged antenna devices 1 and the side boundaries I ¹ is a transversely to the passageway 3 and transverse and in particular perpendicular to the transmission direction 3 ^■ extending passage zone formed, the to be monitored by the antenna device.

Furthermore, in FIG. antenna 15 shown. These are not part of the present invention of a Goods Identification System (WIS). This merely serves to illustrate that the inventive RFID antenna arrangement for a goods identification system (WIS) can also be accommodated in a side boundary 1 'in which, for example, an antenna device for a conventional electronic article security system ( EAS), for example using rectangular frame antennas 15th

A transmitting and / or evaluating unit 17 is preferably provided in the foot region 1 "of this side boundary 1.

If the antenna devices according to the invention for the below explained in further detail electronic goods identification system (WIS) in an existing electronic article surveillance system (EAS) to be retrofitted, with respect to such EAS systems to those known in the art Systems referenced. Such systems typically operate in a frequency range of e.g. 10 Hz to 20 kHz (when, for example, an electromagnetic method is used or, for example, at 8 to 9 MHz (typically around 8.2 MHz) when, for example, a radio-frequency method is used).

For the product identification system (WIS) described in more detail below, a UHF RFID arrangement is used, for which additional antennas in the form of patch antennas are provided.

This system (WIS) serves - as stated - above all by using tags with microchips to capture and read out product-related information, ie information about those goods on which the tag in question is appropriate. Ultimately, however, in a further step, this information can also be used to ultimately build an electronic article surveillance device (if, for example, the product-related information stored on the tag is read out and, for example, compared with information stored via a cash register system in order to query it whether or not a product bearing the date has already been paid for).

Already in Figure 1, a first embodiment of the UHF RFID goods identification system is shown in a schematic representation.

There are each a pair of patch antennas 21 in an upper region and two further pairs of patch antennas 21 in a lower region of the side boundary 1 'and the lateral antenna device 1 are arranged, in the embodiment shown when viewed transversely to the side boundaries within the frame-shaped loop antennas 15th

The patch antennas are antennas, which in accordance with the illustration of Figure 3 in vertical

Top view and in Figure 4 in transverse view a substrate 23rd

(Of dielectric material or for example air), wherein above or below the substrate 23, an upper patch surface 25 and a lower ground surface 27 is provided. The patch surface 25 and the ground surface 27 are at a distance 23 'corresponding to Thickness of the substrate 23 arranged to each other.

4, the two patch antennas 21 are arranged parallel in front of a ground plane 31, in such a way that the lower ground plane 27 of the respective patch antenna 21 is galvanically isolated from the ground plane 31 (ie in a capacitive arrangement to) comes to rest. In this case, the ground plane 31 projects beyond the patchan antennas in plan view and projects laterally over the patch antennas in all directions. The ground surface 31 may consist, for example, of metal or a metal sheet or, for example, of a copper-coated printed circuit board.

That the ground plane 27 of the patch antenna 21 is galvanically isolated from the common ground plane 31 is particularly useful when using conventional patch antennas which are adhered to the ground plane 31 using an adhesive (if it is not electrically conductive), for example. In principle, a mentioned patch antenna with its lower ground surface 27 could also be placed directly on the ground surface 31 to produce a direct current or galvanic contact. In this case, it is in principle also possible that, for example, the ground surface 27 located on the substrate is dispensed with, namely, namely, when the patch antenna is constructed directly with its substrate on the ground surface 31.

Further, in the illustrated embodiment, in the lower common ground plane 31, a passage opening 31 ', in the respective ground plane 27 belonging to the patch antenna 21, a passage opening congruent therewith 27 'and through the substrate 23 passing through a passageway 35 is formed, so that extends through this entire arrangement, a feed line 37 which is electrically galvanically connected to the overhead patch surface 25 at a feed point 25'.

Alternatively, however, a capacitive coupling in the region of the feed point 25 'with the patch surface 25 is possible. Finally, it is also possible to feed the patch surface 25 such that, for example, the feed line 37 is connected to the patch surface lying on the surface of the substrate 23 and / or running (ie plane-parallel to the plane of the patch surface), for example at the edge of the patch surface. However, the patch surface can also have, for example, a U-shaped recess or the like, so that the feed line running in the plane of the patch surface 25 is further inwardly offset, for example, at the end of the U-shaped recess (ie opposite the peripheral edge of the patch surface). is electrically connected to the Patchflä-.

In the embodiment shown, the underlying ground surface 27 extends to the peripheral side surface 123 of the substrate 23, whereas the apparent in the plan view of Figure 3 patch surface 25 at a distance 39 before the side boundary or side surface 123 of the substrate 23 ends, so in plan view with smaller Longitudinal and transverse extension is formed as the lower ground surface 27 of the patch antenna 21st

In the embodiment shown, the at least approximately square-shaped surface of the patch antenna 21 is at two diagonally opposite corners with a Bevel 41 provided, which serves the tuning of the antenna.

If air is used as the substrate 23, corresponding dielectric spacers serving only the mechanical support of the patch surface 25 would have to be used, over which the patch surface 25 is held and fixed at a distance from the ground surface 21.

Two patch antennas formed in accordance with the exemplary embodiment according to FIGS. 3 and 4 are arranged at a lateral spacing 43 (that is to say at a clear lateral spacing 43 between two side boundary surfaces 123 of the two adjacent patch antennas facing each other), namely on a common ground plane 31.

In the exemplary embodiment shown, the distance between the two center points of the patch antennas or the centers of gravity of the two patch antennas is designated 45.

This center distance 45 should be greater than or equal to 0.2 times λ (lambda) based on the operating frequency of the patch antennas used, preferably the center wavelength of the frequency used, for example 0.2 × 34 cm ≦ 5 cm are.

An optimal distance could be at

0.5 x λ (s 0.5 x 34 cm s 17 cm)

especially if, for example, the UHF RFID antenna system operates at a frequency of 868 MHz. The patch antennas do not necessarily have to be the same or the same size. They also do not necessarily have to be arranged next to one another exactly in the horizontal offset, that is to say in the direction parallel to the passage direction 3 '(it being assumed in the exemplary embodiment shown that the passage direction 3 ¹ extending in the horizontal direction runs parallel to the bottom surface 5).

It is further indicated with reference to FIG. 5 that a cooperating patch antenna pair does not basically have to be formed from two overall individual patch antennas 21, but may have a common construction.

The patch antenna pair according to FIG. 5 has a common ground surface 27 on the underside of a common substrate 23, the two separate patch surfaces 25, which are fed via a separate feed line 37, being formed on the upper side of the substrate 23 which ends at a feeding point 25 'on the associated patch surfaces 25. The patch antenna pair thus formed is arranged at a small distance above the common ground surface 31, so that the ground surface 27 extends on the underside of the substrate in close proximity to the common ground surface 31.

The patch antenna pairs partially shown in the figures are arranged offset in the forward direction 3 'to each other. They do not have to be arranged exactly parallel to the passage direction 3 '. In particular, even if, for example, the passage widens conically or tapers, the lateral distance from a vertical plane lying in the passage direction 3 'to the relevant patch face 25 of a patch antenna 21 could be reduced. be different. The mentioned patch antenna pair represents a basic embodiment of the invention in which at least two patch antennas 21 form a first group A of cooperating patch antennas. It can be arranged offset in the passage direction or with a component in the passage direction to each other but still several patch antennas, for example, three patch antennas, etc.

It is shown with reference to FIG. 6 that such a cooperating pair of patch antennas 21 can be arranged not only in the forward direction 3 'but also in the vertical or vertical direction 7 with a certain offset from one another. However, a maximum deviation in height and / or vertical direction is preferably to be carried out such that a straight line 47 laid through the center or center of gravity of the associated pair of patch antennas leads to a horizontal plane or to a plane parallel to the passageway or bottom surface 5 48 includes an angle α that is less than or equal to 45 °.

In addition, however, the patch antennas shown in FIGS. 1 to 6 could also be arranged twisted relative to one another, so that in the case of a patch antenna, the feed point 25 'is more at the top and at the adjacent patch antenna at the bottom or at one antenna rather at the right and at the other Patch antenna, for example, rather on the left side, etc. is located. Again, there are basically no restrictions.

It is shown with reference to FIG. 7 that, for example, a group of four of patch antennas 21 or several groups of two or four etc. in an antenna device 1 can be used.

In this case, in the embodiment according to FIG. 7, in addition to a lower or lower patch antenna group A (in the exemplary embodiment shown in the form of a patch antenna pair A), a second patch antenna group B is higher (in the embodiment shown in FIG Form of a higher-lying patch antenna pair B) is provided, wherein the higher-lying patch antenna pair B although with a same vertical or vertical offset (which need not necessarily be so) is arranged, but in the forward direction 3 'differently positioned opposite the lower patch antenna pair A. This results in a larger lateral offset 43 to 45 between the two patch antennas 21 of the higher patch antenna pair. As already mentioned, each of the mentioned groups A or B or each further patch antenna group can also have more than two patch antennas, which are arranged offset in the passage direction or at least in one component in the passage direction.

Notwithstanding the embodiment shown, the feed points 25 'but come to rest at different locations, so not all with the same orientation, as shown in Figure 7.

The clearances 43 in the horizontal or passage direction 3 ¹ or in the vertical or vertical direction 7 can be of the order of magnitude of a few mm to a few cm (without any fundamental restriction to this size range). In this exemplary embodiment, there is now the further advantage that, for example, the lower row A of patch antennas 21 relative to the upper row B of patch antennas 21 can be fed to one another with a phase shift, resulting in an electrical uptilt or, depending on the arrangement, if desired, create a so-called electrical down-tilt. In other words, the main emission direction or main lobe is thereby electrically pre-set in ascending vertical orientation or rather in lowered vertical orientation. In this way, therefore, a specific fine adjustment of the monitoring area can be made.

If, for example, the mentioned four patch antennas are used in the lower monitoring area X1 (FIG. 1) according to FIG. 1, the control of the patch antennas can take place so that the monitoring area is electrically preset from the lower floor upwards.

If such a patch antenna group shown with reference to FIG. 7 is used, for example, in the lower region of the antenna device 1 (as shown in FIG. 1), a different phase control with respect to the patch antennas arranged one above the other in the various rows or planes can be carried out in such a way that For example, the main lobe or the main monitoring area is not perpendicular to the ground plane 31 of the patch antennas, but is aligned with a component in the vertical direction running upward.

If a corresponding patch antenna group according to FIG. 7 is, for example, in the upper region X2 (FIG. 1) of FIG Antenna device 1 used here, a different phase feed could be made, for example, so that the main beam direction of the patch antennas is oriented in a certain angle range rather downwardly extending into the surveillance area inside.

Likewise, however, the different phase control between the two patch antennas 21 of a group A and / or B arranged adjacent to one another approximately at the same height can be such that the alignment of the monitored area corresponds to the main beam direction (direction of the main lobe) of the patch antenna in one or in opposite directions set direction with respect to the passageway 3 is deflected out of a transverse to the middle symmetry plane out.

2 shows only schematically that additional patch antennas 21 may be provided, for example, additionally in the floor area or in the ceiling area or for example at the foot area 1 "of the antenna device 1 (or also at the upper end area of the antenna device 1) However, in this case as well, at least one pair of patch antennas or, for example, three, four or more patch antennas, in particular in the direction of passage or with a component in the passage direction, are used, at least one pair of patch antennas or, for example, three, four or more patch antennas In this case, patch antennas provided on the upper end region can also be aligned in a preset manner upwards or downwards, in particular if electronic beamforming and alignment, as explained above with reference to FIG. 7, are not undertaken. If the patch antennas mentioned in the lower or upper region of the side parts 1 'or in the bottom region or above the passageway (for example in a ceiling or suspended therefrom) are used as additional patch antennas, individual patch antennas can also be used here. Preferably, however, two or more patch antennas lying side by side in the passage direction or at least offset with one component in the passage direction are also used here, which thus form groups of patch antennas which interact.

Based on Figures 1 and 2 and Figure 8 is further shown that, for example, the two side antenna devices 1, so the two side boundaries 1 'can be arranged at a side distance 51 from each other, for example, between 0.8 m to 2.5 m, in particular can vary between 1.4 and 2.0 m (these limits can be under or exceeded).

Preferably, the lateral antenna device 1, ie the side boundary I ^1, a height 7, which may be, for example, 1.0 m to 1.80 m or 2.0 m on average.

The height of a patch antenna or patch antenna pair, i. in particular the associated ground surface 31, for example, may preferably be between 5 cm to 40 cm.

If two patch antenna combinations 125a and 125b are used according to FIGS. 1, 2 or 8 (ie, for example, a patch antenna combination A and a patch antenna combination B which are located in the lower region X1 and in the upper region rich X2 according to FIGS. 1, 2 or 8), the distance 55 of the lower patch antenna combination 125a to the bottom surface should be at least 0.3 to 1 m. The distance 57 between the lower patch antenna combination 125a and the upper patch antenna combination 125b should preferably be between 0.1 m to 2 m, in particular around 0.2 m to 1.2 m. The distance can also be arbitrarily greater if particularly high side boundaries 1 'are used and the upper antenna devices are to be particularly located.

If only one patch antenna combination with associated ground plane 31 is used, as shown for example with reference to FIG. 9, then the distance of this patch antenna combination 125 to the bottom 5 should have a dimension of at least 0.5 m and more, the overall height of the arrangement again can be 1 to 2 m.

The patch antennas 21 used to enable an electronic goods identification system (WIS) operate preferably in the UHF frequency range, ie for example in an 800 MHz to 950 MHz or 1000 MHz range (in particular in the range of 868 MHz). If this WIS system is used in addition to a conventional EAS monitoring system which operates without the patch antennas mentioned, it is preferred to use a conventional monitoring system, for example in the 10 Hz to 20 kHz (in particular in electromagnetic EAS methods) or for example in the 5 MHz to 10 MHz range (for example around 8, 2 MHz), in particular if it is a radio-frequency EAS method.

The patch antennas used in accordance with the invention are used for an RFID surveillance system used, so that products to be monitored, goods and / or persons, etc., can be detected if they still carry an RFID tag with him, recognized during the passage along the Durchlassweges and the corresponding information by means of a provided for this purpose "readers" can be read and evaluated.

The system according to the invention has been described in particular with reference to a passageway. However, the monitoring system with a passage gate along a passageway described in particular with reference to FIGS. 1 and 2 can also be constructed such that corresponding side boundaries are arranged several times side by side in the lateral spacing, for example five side boundaries I ¹ , whereby four parallel passageways 3 are defined. In the central antenna devices 1 (that is to say, not in the extreme antenna devices 1), patch antennas are then installed in such a way that they radiate partly in one direction and partly in the opposite direction for detecting both transmission paths.

Basically, the mentioned antenna devices 1 for monitoring a passageway are used and used in such a way that a pair of such antenna devices 1 is provided, ie in each case a corresponding antenna device 1 or a side boundary I ¹ , which are arranged opposite to the passage to be monitored ,

By the described, used in the forward direction two or also used in the forward direction several Patch antennas is thus ensured that a smearing of the monitoring area in the direction of the passageway in terms of a narrow passage zone as possible is effected. In other words, there is thus a bundling of the antenna field and thus of the monitoring area in the horizontal plane (with a horizontally extending passageway), so that a passage zone (monitoring area) monitored by the antenna device extends in the forward direction 3 'only to the smallest possible extent.

Claims

Claims;

1. RFID antenna system for a goods identification system (WIS) with the following features: - at least one RFID antenna device (1) for a goods identification system (WIS) is provided, wherein by means of the at least one RFID Antenna device (1) information from equipped with a microchip RFID tags are readable - the at least two RFID antenna devices (15, 1) are on one side with respect to a in the forward direction (3 ¹ ) extending passageway (3) or provided on two opposite sides with respect to a passageway (3) extending therebetween in a direction of inclination (3 ¹ ), thereby creating a monitoring area,

- The RFID antenna device (1) comprises at least two antennas, which are provided on one side of the passageway (3) to be monitored, - the at least two antennas consist of Patchanten ^¬ nen (21),

- The patch antennas (21) of the RFID antenna device (1) are aligned parallel or substantially parallel or with a component parallel to the passageway (3), the at least two patch antennas (21) are in the direction of the passageway (3) or at least with a component in the forward direction (3 ¹ ) offset from one another, characterized by the following further features: the at least two patch antennas (21) form a patch antenna group (A, B) for focusing and thus narrowing the monitoring area in the forward direction (3 ¹ ), and the at least two patch antennas (21) are in a same distance from a bottom surface (5) of the passageway (3) and / or arranged on the same horizontal plane or offset, in such a way that a through the center and / or center of gravity of at least two adjacent patch antennas (21) laid straight against a Horizontal plane and / or to the bottom surface (5) parallel plane includes an angle α, which is <45 °.

2. RFID antenna system according to claim 1, characterized in that in the forward direction (3 ¹ ) more than two patch antennas (21) are arranged with lateral offset to each other.

3. RFID antenna system according to claim 1 or 2, characterized in that a plurality of groups (A, B) of two or more mutually offset with side offset patch antennas (21) at different altitudes, in particular at different altitudes relative to the level of the bottom surface (5) are arranged to each other.

4. RFID antenna system according to claim 3, characterized in that two groups (A, B) arranged at different altitudes of patch antennas (21) with different phase angles are used to produce a different up-tilt or down-tilt. Winkels are controlled.

5. RFID antenna system according to claim 3 or 4, characterized in that at least two in the forward direction

(3 ¹ ) mutually offset patch antennas (21) of a group (A, B) of patch antennas (21) are driven with different phase angle, about which the monitoring range in one or in the opposite direction to the passage direction (3 ¹ ) is adjustable.

6. RFID antenna system according to one of claims 1 to 5, characterized in that only one or more cooperating groups (A ₇ B) of patch antennas in an RFID antenna device (1) are provided.

7. RFID antenna system according to claim 6, characterized in that the at least one or more cooperating groups of patch antennas are arranged at a height opposite the passageway (3) and / or the bottom surface (5) of the passageway (3) which is ≥ 0.3 m and <2 m.

8. RFID antenna system according to one of claims 1 to 6, characterized in that a plurality of areas (Xl, X2) are provided with one or more cooperating groups (A, B) of patch antennas (21), which in a lower height range of the RFID antenna device (1) or side boundaries (I ¹ ) and a higher range of the RFID antenna device (1) or the side boundaries (I ¹ ) are arranged.

9. RFID antenna system according to claim 8, characterized in that between two offset in vertical and / or height direction provided areas (Xl, X2) arranged, one or more cooperating groups (A, B) antenna devices comprising patch antennas (21) have a height distance of at least 0.1 m and preferably less than 2.0 m, 1.2 m and preferably less than 0.6 m, and that the height distance of the bottom patch antennas (21) or a lowermost group of patch antennas (21) to the bottom surface (5) of the passageway (3) at least 0.3 m, preferably 0.3 m to 1.5 m or in particular to 1.2 m is.

10. RFID antenna system according to one of claims 1 to 9, characterized in that the patch antennas (21) radiate in the UHF range, preferably in the 800 MHz to 1000 MHz band, in particular at 868 MHz.

11. RFID antenna system according to one of claims 1 to 10, characterized in that the patch antennas (21) comprise a patch surface (25), an underlying substrate (23) and an underlying ground surface (27), and that the patch antenna (21) thus arranged capacitively in front of a ground plane (31) or DC-connected or galvanically connected to the ground plane (31), the patch antenna (21) and the ground plane (31) being transverse and preferably perpendicular to the passageway (3) and / or to the passage direction (3 ¹ ) is aligned.

12. RFID antenna system according to one of claims 1 to 10, characterized in that the patch antenna (21) comprises a patch surface (25), a substrate underneath (23) and a ground surface (31), wherein the patch antenna (21) and the ground surface (31) is oriented transversely and preferably perpendicular to the passageway (3) and / or to the passage direction (3 ¹ ).

13. RFID antenna system according to claim 11 or 12, characterized in that the substrate (23) consists of a dielectric body.

14. RFID antenna system according to one of claims 11 to

13, characterized in that the substrate (23) consists of air and the electrical spacers for positioning and holding the patch surface (25) are provided.

15. RFID antenna system according to one of claims 1 to

14, characterized in that at least one group (A, B) of patch antennas comprises at least two mutually offset patch antennas (21) which are arranged in front of a common ground plane (31).

16. RFID antenna system according to claim 15, characterized in that a group (A, B) of at least two patchchantennen antennas (21) comprise a common substrate (23), preferably provided on the back of a common ground surface (27) is, wherein on the radiator side on the substrate (23) opposite to the ground surface (27) at least two galvanically separated patch surfaces (25) are formed.

17. RFID antenna system according to one of claims 6 to 16, characterized in that each patch antenna (21) comprises a feed line (37) having a passage opening (31 ') in the ground surface (31), a subsequent thereto Transmit passageway (27 ') in the respective ground plane (27) of the patch antenna (21) and a subsequent channel (37) extending through the substrate (23) to a feed point (25') on the patch face. (25), wherein the feed point (25 ¹ ) is preferably located at the bottom of the patch surface (25).

18. RFID antenna system according to one of claims 1 to 17, characterized in that a group (A, B) of patch antennas (21) in front of a common ground surface (31) is arranged, the height dimension preferably between 5 cm to 40 cm is.

19. RFID antenna system according to one of claims 1 to 18, characterized in that preferably additional patch antennas (21) are provided, preferably in the lower region of the RFID antenna device (1) and / or the side boundary (I ¹ ) on Transition region to the bottom surface (5) are provided, the main beam direction and / or patch surface (25) is preferably directed in advance with an upward-facing vertical component.

20. RFID antenna system according to one of claims 1 to 19, characterized in that one or more patch antennas (21) are preferably provided at the upper end of the RFID antenna device (1) and / or the side boundaries (I ¹ ) whose Main beam direction and / or patch surface (25) are mounted in a forward direction with a downward vertical component.

21. RFID antenna system according to one of claims 1 to 20, characterized in that at least two in the forward direction (3 ¹ ) and / or at least two offset in height and / or vertical direction to each other, cooperating patch antennas (21) are provided , which are driven with different phase and preferably different adjustable phase.

22. RFID antenna system according to one of claims 1 to

21, characterized in that preferably in the region of the bottom surface (5) and / or above the passageway (3) at least one and preferably a plurality in the passage direction (3 ¹ ) offset from each other patch antennas (21) are provided.

23. RFID antenna system according to one of claims 1 to

22, characterized in that the patch antennas (21) to at an electronic article-backup system

(EAS) belonging antennas and / or loop antennas (15) can be retrofitted and / or integrated.

24. RFID antenna system according to one of claims 1 to 23, characterized in that a plurality of RFID Antennenein- directions (1) and / or side boundaries (I ¹ ) are arranged with lateral offset to form a plurality of extending therebetween passageways (3) in which in the middle RFID antenna devices (1) and / or side boundaries (I ¹ ) patch antennas (21) are installed, which are partially in one direction and partly in the opposite direction for monitoring two adjacent passageways (FIG. 3) radiate.

25. RFID antenna system according to one of claims 1 to 24, characterized in that the article security system (EAS) belonging to frame antennas (15) are provided, and that at least one patch antenna (21) in a loop antenna (15 ), and that preferably the patch antennas (21) are integrated in plan view of the loop antennas (15) within the loop antennas (15).