Apparatus and method for reading identification of moving object

Abstract

The invention relates to a device and a method for reading a transponder of a moving object, by means of which a plurality of objects can be detected at the same time, more specifically regardless of the position and direction of travel of the object. This is achieved in that the device for reading UHF RFID signals emitted or reflected from the identified at least one transponder (13) has at least one UHF RFID reading device (14). If the identification can be, for example, a license plate of a motor vehicle, it can be conceived that the moving object is the motor vehicle (10). The at least one reading device (14) for reading the transponder (13) may be located alongside, above, or in a roadway (11) on which the object moves. The invention is characterized in that the at least one reading device (14) has an antenna designed as a monopole antenna.

Description

Technical Field

[0001] The invention relates to a device for reading UHF RFID signals according to the preamble of claim 1. Furthermore, the invention relates to a method for reading UHF RFID signals according to the preamble of claim 19. Background Art

[0002] In order to identify mobile objects, such as motor vehicles, it is known that these objects are equipped with transponders that can be read without contact. These transponders have a data storage device on which any data about the object can be stored. In the case where the transponder is arranged on the motor vehicle, the data can be, for example, information about the vehicle, the owner, insurance, license, etc. It is well known that these transponders can be fixed in signs or labels on the motor vehicle or on the windshield. Other embodiments provide that the transponder that can be read without contact is integrated in the logo. The logo can be, for example, a motor vehicle license plate fixed to the vehicle.

[0003] To read the transponder, a handheld scanner can be used, with which the transponder on a stationary object is read. To this end, the handheld scanner emits a UHF (or NFC) RFID signal that is detected or reflected by the transponder. The information stored in the data memory can be read using the signal emitted or reflected by the transponder. In the case of moving objects, the handheld scanner can only function very limitedly or not at all. In order to read a transponder arranged on a mobile object or on a moving motor vehicle, it is known to arrange a reading device with an antenna near the road. Here, the reading device can be located in a corresponding device next to or above the road. Also known are embodiments in which the reading device or the antenna is integrated into the road surface. In order to read the RFID signal of the transponder, it is known to use a UHF antenna.

[0004] As long as moving objects or motor vehicles approach the antenna from a specific direction and at sufficiently large time intervals, the transponders can be read at least largely reliably. However, if the transponders of multiple vehicles are to be read on a busy, possibly multi-lane street and the vehicles are coming from different directions (as can be the case at an intersection, for example), the known reading devices reach their technical limits. It is therefore no longer possible to reliably read the transponders of all vehicles. As a result, such antennas are not usable, in particular, for detecting toll vehicles. Summary of the invention

[0005] Starting from this, the object of the present invention is to provide a device and a method for reading transponders of mobile objects, by means of which a plurality of objects can be detected simultaneously, specifically independently of the position and direction of travel of the objects.

[0006] The device for solving this task has the features of claim 1. It is therefore provided that the device for reading the UHF RFID signal emitted or reflected by at least one transponder of the identification has at least one UHF RFID reading device. When the identification can be, for example, a motor vehicle license plate, it is conceivable that the mobile object is a motor vehicle. The at least one reading device can be located next to, above or in the road on which the object moves in order to read the transponder. The invention is characterized in that the at least one reading device has an antenna configured as a monopole antenna. The antenna has a conductive plate element and conductive first and second rod elements. Here, these rod elements are arranged vertically on the plate element and are galvanically separated from the plate element. It can be provided that the device according to the invention is integrated into the road surface, or is positioned next to the road as at least one column, or is fixed on a crossbeam above the road. Through the invention, multiple mobile transponders can be read simultaneously or at short time intervals. Here, a directional signal is emitted by the antenna, which is detected by the transponder and is re-emitted or reflected. The information detected by the antenna is then analyzed by a control unit. Here, the position of the transponder or object relative to the antenna is not important. In this way, not only transponders moving towards the antenna against the direction of travel of the object can be detected, but also transponders moving away from the antenna in the direction of travel of the object can be detected. The invention thus makes it possible to detect not only transponders arranged in the front area of ​​the vehicle, but also transponders located at the rear of the vehicle. Transponders of objects passing the reading device laterally, diagonally or transversely can also be detected.

[0007] Since it is possible to detect transponders in any position relative to the antenna and thus to detect moving objects, the device according to the invention is also able to determine the motion profile of an object or the speed of an object. In particular, due to the high detection rate and the large range of detection levels, the claimed device is particularly well suited for reading a plurality of transponders moving around the antenna, as is the case, for example, on busy streets or intersections. It is conceivable that a plurality of devices according to the invention are arranged spaced apart from one another and / or at different positions relative to the road, in order, for example, to generate redundant data detection or to detect vehicles on a plurality of streets. By comparing the data recorded at different times, information about traffic flow and traffic development can also be determined.

[0008] Preferably, it is provided that the plate element and the rod element of the reader or antenna are provided with a voltage source of the feed network. The UHF RFID signal can be applied between the plate element and the rod element via this voltage source. By controlling the voltage accordingly, the signal of the reader can be radiated in different spatial directions. By means of this variable radiation characteristic of the antenna, at least nearly all transponders or objects surrounding the reader can be detected.

[0009] In particular, it is provided that the first rod element and the second rod element are arranged at a spacing of one quarter to three quarters of the wavelength of the UHF signal relative to each other. This spacing of the two rod elements enables destructive and constructive superposition of the electromagnetic waves emitted by the two rod elements. Depending on the amplitude and phase shift of the signals fed into the two rod elements, a radiation characteristic of the antenna adapted to the situation can be generated in a targeted manner.

[0010] Another advantageous embodiment can provide that the first rod element and the second rod element are arranged at a spacing of half a wavelength relative to one another. This also results in the possibility of selectively producing the radiation characteristic of the measuring device by correspondingly controlling the rod elements.

[0011] Preferably, the present invention can also provide that the feeding network is implemented so that a UHF RFID signal can be applied between the plate element and the second rod element using a voltage source, and its phase is the same as the phase of the UHF RFID signal applied between the plate element and the first rod element. It is also conceivable that the feeding network is implemented so that a UHF RFID signal can be applied between the plate element and the second rod element using a voltage source, and its amplitude is the same as the UHF RFID signal applied between the plate element and the first rod element. When the two rod elements are fed with UHF RFID signals of the same phase and the same amplitude, a radiation characteristic with two main lobes is achieved. These main lobes are significantly displaced downward (towards the direction of the plate element) compared to the elliptical ring of a simple monopole antenna. It has been proven to be particularly advantageous that the diameter of the plate element can be less than 0.5m in order to achieve the effect. Due to the directional radiation characteristics to be achieved, a higher radiation transmission power can be used. This enables the detection range of the reading device to be wider, which leads to a more reliable detection rate and a higher detectable object speed.

[0012] A particularly advantageous embodiment can provide that the monopole antenna has a third and a fourth rod element which are arranged perpendicularly to the plate element and are electrically conductive, and that the third and the fourth rod element are arranged at intervals of one quarter to three quarters of the wavelength of the UHF signal relative to one another, and that the connecting line between the first and the second rod element and the connecting line between the third and the fourth rod element intersect each other halfway along their course, and that the two connecting lines are arranged orthogonally relative to one another. It is conceivable that the third and the fourth rod element are arranged at intervals of one half of the wavelength of the UHF signal relative to one another.

[0013] It is also conceivable that the feed network is implemented in such a way that a UHF RFID signal can be applied between the plate element and the third rod element and between the plate element and the fourth rod element by means of a voltage source, which is phase-shifted by 180° compared to the UHF RFID signal applied between the plate element and the first rod element. It is also conceivable that the feed network is implemented in such a way that a UHF RFID signal can be applied between the plate element and the third rod element and between the plate element and the fourth rod element by means of a voltage source, which has the same amplitude as the UHF RFID signal applied between the plate element and the first rod element. By means of such an arrangement of the rod elements, UHF RFID transponders can be detected in multiple spatial directions. Depending on the requirements, the detection direction can be changed at a high detection rate.

[0014] In particular, it is conceivable to implement the vertically arranged rod element as a top-loaded monopole. It is provided that the rod element has an electrically conductive disk element at its end facing away from the plate element, which disk element has a circular, oval, square or rectangular shape. This makes it possible to shorten the length of the rod element and ensure that the resonant frequency of the antenna is maintained. Thus, for example, a length of 3 cm is sufficient for the rod element. By means of this measure, the entire antenna arrangement can be further flattened, which simplifies integration into the device.

[0015] Another conceivable embodiment can provide that the feed network is designed in such a way that three of the four rod elements can be short-circuited to the plate element and a UHF RFID signal can be applied between the plate element and the remaining rod element by means of a voltage source. The three short-circuited rod elements thus act as reflectors for the electromagnetic radiation emitted by the remaining rod elements. This has the advantage that, for example, for applications on motorways or highways for individual lanes, the radiation characteristic can be directed in the direction of an oncoming vehicle, so that a longer detection zone and thus a higher detection speed can also be achieved.

[0016] Furthermore, the invention can provide that the radiation characteristic of the at least one antenna can be varied by a voltage source, in particular periodically. This variant allows the device to be used in a situation-dependent and thus highly flexible manner.

[0017] Another embodiment can provide that the plate element has a conductive border on its plate edge pointing in the direction of the rod element, and the height of the border extends at least up to the height of the end of the rod element facing away from the plate element. It can also be provided that the feed network and / or the voltage source are integrated in a housing arranged on the side of the plate element facing away from the rod element. It is also conceivable that the antenna is integrated into the road surface so that the side of the plate element facing the rod element is oriented in the direction of the road surface. Preferably, it is provided that two, three, four or more reading devices are arranged next to and / or above and / or on and / or in the route traveled by the mobile object in order to detect multiple objects simultaneously.

[0018] The method for solving the object has the measures of claim 19. It is therefore provided that a UHF RFID signal emitted by at least one transponder of an identification of a mobile object, in particular a motor vehicle license plate, or reflected by the at least one transponder is read. In this case, the reading is carried out using a device according to at least one of claims 1 to 18. The method according to the invention is characterized in that the radiation characteristic of at least one antenna is changed so that it is oriented in the direction of the mobile object. As a result, each transponder of the object can be detected and read, regardless of its position relative to the device. With the method described here and the device described, this can be carried out at a high sampling rate.

[0019] Preferably, the invention provides that, in order to change the radiation characteristic, the voltage between the plate element and the at least two rod elements of the antenna is changed. By changing the voltage, the radiation characteristic can be emitted in almost any direction.

[0020] Preferably, it is conceivable to read UHF RFID signals from transponders close to the antenna and / or from transponders far from the antenna by changing the radiation characteristic of the at least one antenna. The radiation characteristic of the at least one antenna can be changed so that UHF RFID signals can be read in a range of 360° around the antenna, in particular in the forward, backward, sideways or diagonal direction. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] The preferred embodiments of the present invention are explained in more detail below with reference to the accompanying drawings, wherein:

[0022] Figure 1a A schematic diagram showing a possible embodiment of the method according to the invention;

[0023] Figure 1b Show according to Figure 1a Another schematic diagram of the method;

[0024] Figure 2 A schematic diagram showing another embodiment of the method according to the present invention;

[0025] Figure 3 A schematic diagram showing another embodiment of the method according to the present invention;

[0026] Figure 4 A schematic diagram showing another embodiment of the method according to the present invention;

[0027] Figure 5a A schematic diagram showing a device according to the present invention;

[0028] Figure 5b Show according to Figure 5a Graphical representation of the radiation characteristics of the device;

[0029] Figure 6a A schematic diagram showing another embodiment of the device according to the present invention;

[0030] Figure 6b Show according to Figure 6a Graphical representation of the radiation characteristics of the device;

[0031] Figure 6c Show according to Figure 6a a graphical representation of another radiation characteristic of a device; and

[0032] Figure 7 A schematic diagram shows a further embodiment of the device according to the invention. DETAILED DESCRIPTION

[0033] The method according to the invention makes it possible to read a plurality of transponders of a mobile object independently of its direction of movement. The mobile object may be a motor vehicle. The transponder may be located, for example, on or in the number plate of the motor vehicle or in a windshield label, and it is also conceivable that the transponder is located on the tires of the vehicle, under the vehicle or at other locations of the vehicle. The data stored on the transponder and to be read may be used in connection with a toll system, a parking system, a refueling application or the authentication of the vehicle or the owner of the vehicle. In order to read the data contactlessly, the invention provides a device with a reading device, which is assigned to the road on which the motor vehicle moves. A number of conceivable embodiments are shown in the drawings. However, it should be expressly pointed out that the invention is not limited to the embodiments shown here. On the contrary, the intended scope of protection also includes other embodiments.

[0034] Figure 1a Two motor vehicles 10 are shown moving on a road 11 in a direction of travel 12. The motor vehicles 10 each have a transponder 13 in the front region and in the rear region. These transponders 13 can be integrated, for example, in the number plates of the motor vehicles 10. Alternatively, it is also conceivable that the transponders 13 are fastened at another location on the motor vehicle 10 or on another component of the motor vehicle 10, for example on a wheel.

[0035] exist Figure 1a In the embodiment of the method according to the invention shown in FIG. 1 , a reader 14 is integrated into the road 11 for transmitting and receiving UHF RFID signals. The reader 14 has at least one antenna, a control device 30 and an energy supply device or a feed network 31. Since the reader 14 is integrated into the road 11 or into the surface of the road 11, it is positioned directly next to the motor vehicle 10 without hindering the vehicle 10. The output signal 15 is emitted by the reader 14, as in Figure 1a. These output signals 15 can be focused or directed by the control device 30 so that they are directed toward the detected transponder 13. In this case, both transponders 13 from a motor vehicle 10 approaching the reading device 14 and transponders 13 from a motor vehicle 10 moving away from the reading device 14 as viewed in the direction of travel 12 can be detected. The output signals 15 are reflected by the transponder 13 or the transponder 13 (which can be an active or passive RFID chip) emits an input signal 16 ( Figure 1b ). These reflected or incoming signals 16 are detected and evaluated by the reading device 14. By evaluating the signals, the information stored in the data memory of the transponder 13 can be detected.

[0036] Except in Figure 1a and Figure 1b In addition to the embodiment shown in FIG. 1 , it is also conceivable that the reading device 14 is arranged in a column 17 beside the road 11 ( Figure 2 ). Here, the transmission and reception principles are the same as in the previously described embodiment. By positioning the reading device 14 in the column 17, the transmission or reception level of the reading device 14 can be increased.

[0037] Finally, it is also conceivable that the reader device 14 is accommodated in a crossbar 18 that spans the road 11. This allows both a high transmission or reception level of the reader device 14 and an advantageous proximity of the reader device 14 to the motor vehicle 10 to be achieved.

[0038] By means of the method described here or by means of the reading device 14, not only motor vehicles 10 on one road 11 but also motor vehicles on a plurality of adjacent roads 11 can be detected. Figure 4 As schematically shown in FIG. 1 , the output signal 15 can be emitted not only parallel to the road 11 in the direction of travel 12, but also perpendicularly thereto, so that multiple motor vehicles 10 can also be detected on other roads 11. This is particularly advantageous on busy streets and in intersections. Likewise, the presence of vehicles 10 on different roads 11 can be detected. Figure 4 By continuously detecting the signal, the reading device 14 can not only read information about the motor vehicle 10, but also detect its speed.

[0039] exist Figure 5a A possible embodiment of a reader 14 or antenna arrangement for UHF RFID signals is shown in FIG. The antenna arrangement is characterized in that two electrically conductive rod elements 20, 21 are arranged perpendicularly on the plate element 19 relative to the plate element 19. An important feature of this arrangement is that the spacing between the two rod elements 20, 21 is half the wavelength of the UHF signal. Figure 5aIn the embodiment shown in , the plate element 19 lies in the xy plane and the two rod elements 20 , 21 are oriented parallel to the z axis.

[0040] The feed network 31 for supplying electrical energy to the reader 14 is designed so that a UHF RFID signal can be applied between the plate element 19 and the second rod element 21 by means of a voltage source, the phase and / or amplitude of which is the same as the UHF RFID signal applied between the plate element 19 and the first rod element 20. In the case of the same phase and amplitude, for Figure 5a The reading device 14 shown in FIG. Figure 5b The radiation characteristic shown in . The radiation characteristic has two main lobes 32, 33, which are displaced in the direction of the plate element 19. This characteristic is produced in the following way: the electric field components of the two electromagnetic rays emitted by the rod elements 20, 21 in the y direction are superimposed constructively and the electric field components in the x direction are superimposed destructively.

[0041] exist Figure 6a Another embodiment of a reading device 14 according to the invention is shown in FIG. In addition to the first rod element 20 and the second rod element 21, the antenna arrangement structure also has a third rod element 22 and a fourth rod element 23, which are also oriented perpendicularly to the plate element 19 and therefore parallel to the rod elements 20, 21. The two rod elements 22, 23 are also configured to be conductive. The third rod element 22 and the fourth rod element 23 are arranged at intervals of half the wavelength of the UHF signal relative to each other. The connecting line between the first rod element 20 and the second rod element 21 intersects the connecting line between the third rod element 22 and the fourth rod element 23 at half of their routes, respectively, and the two connecting lines are arranged orthogonally relative to each other. The four rod elements 20-23 thus form the corner points of a square, wherein the diagonal lines connecting the opposite corner points have a length of half the wavelength of the UHF signal.

[0042] In this embodiment, the feed network 31 is constructed so that a UHF RFID signal can be applied between the plate element 19 and the third rod element 22 and between the plate element 19 and the fourth rod element 23 by means of a voltage source, which is phase-shifted by 180° and / or has the same amplitude as the UHF RFID signal applied between the plate element 19 and the first rod element 20. In the case of a phase shift of 180° and the same amplitude, for Figure 6a The antenna arrangement shown in Figure 6b The radiation characteristic shown in . The radiation characteristic has four main lobes 34 to 37. Here, the feed network 31 can also be designed so that three of the four rod elements 20-23 can be short-circuited to the plate element 19 and a UHF RFID signal can be applied between the plate element 19 and the remaining rod elements using a voltage source. The radiation characteristic of the reader 14 generated in this way is Figure 6c Shown in.

[0043] exist Figure 7 1 shows a further embodiment of a reader 14 according to the invention. The vertically arranged rod elements 20-23 are implemented as top-loaded monopoles. In the embodiment shown, the rod elements 20-23 have an electrically conductive disk element 24-27 at their end facing away from the plate element 19. The disk elements 24-27 shown are designed to be circular. However, it is also conceivable that the disk elements 24-27 are designed to be oval, square, rectangular, etc.

[0044] Furthermore, the plate element 19 has a conductive border 28 on the plate edge pointing in the direction of the rod elements 20-23. The height of the border 28 extends at least up to the height of the end of the rod elements 20-23 facing away from the plate element 19. However, the border 28 can also extend beyond the end of the rod elements 20-23 facing away from the plate element 19. The feed network 31 and the voltage source are integrated in a housing, which is arranged on the side of the plate element 19 facing away from the rod elements 20-23. Optionally, the antenna arrangement can be covered with a non-conductive cover 29, thereby protecting the rod elements 20-23 from mechanical and chemical influences.

[0045] The antenna arrangement shown here is integrated into the road 11 in such a way that the side of the plate element 19 facing the rod elements 20 - 23 is oriented in the direction of the street surface.

[0046] In addition, the present invention is not limited to the first rod element 20 and the second rod element 21 being arranged at an interval of half the wavelength of the UHF signal relative to each other. In other embodiments, the first rod element 20 and the second rod element 21 and / or the third rod element 22 and the fourth rod element 23 are arranged at an interval of one quarter to three quarters of the wavelength of the UHF signal relative to each other. Reference numerals list

[0047] 10 Motor Vehicles

[0048] 11Road

[0049] 12 Direction of travel

[0050] 13 Transponder

[0051] 14Reading device

[0052] 15 Output signal

[0053] 16 Input Signals

[0054] 17 Pillars

[0055] 18 beam

[0056] 19 plate elements

[0057] 20 rod elements

[0058] 21 rod elements

[0059] 22 rod elements

[0060] 23 rod elements

[0061] 24 tray components

[0062] 25 tray components

[0063] 26 tray components

[0064] 27 tray components

[0065] 28 Border

[0066] 29 Cover

[0067] 30 Control device

[0068] 31 Feeding network

[0069] 32 Main lobe

[0070] 33 Main lobe

[0071] 34 Main lobe

[0072] 35 Main lobe

[0073] 36 Main lobe

[0074] 37 Main lobe

Claims

1. A device for reading UHF RFID signals, the UHF RFID signals being emitted by or reflected from at least one transponder (13) of an identification of a mobile object, preferably a motor vehicle (10), in particular a motor vehicle license plate, the device comprising at least one UHF RFID reading device (14), the reading device (14) comprising at least one antenna, and the at least one reading device (14) being integrated beside and / or above and / or on a route, preferably a road (11), travelled by the mobile object, and / or in a pavement of the route, in particular in a pavement of the road, characterized in that The antenna of at least one reading device (14) is designed as a monopole antenna, which has an electrically conductive plate element (19) and first and second electrically conductive rod elements (20, 21), the rod elements (20, 21) being arranged vertically on the plate element (19), and the plate element (19) and the rod elements (20, 21) being galvanically isolated from each other.

2. The device for reading UHF RFID signals according to claim 1, characterized in that: The plate element (19) and the rod elements (20, 21) are provided with a voltage source of a feed network (31) of a UHF RFID reader (14) in order to apply a UHF RFID signal between the plate element (19) and the rod elements (20, 21).

3. The device for reading UHF RFID signals according to claim 1 or 2, characterized in that: The first rod element (20) and the second rod element (21) are arranged relative to each other at an interval of one quarter to three quarters of the wavelength (λ / 4 to ¾λ) of the UHF signal.

4. Device for reading UHF RFID signals according to one of the preceding claims, characterized in that The first rod element (20) and the second rod element (21) are arranged relative to each other at an interval of half the wavelength (λ / 2) of the UHF signal.

5. Device for reading UHF RFID signals according to one of the preceding claims, characterized in that The feed network (31) is designed so that a UHF RFID signal can be applied between the plate element (19) and the second rod element (21) by means of a voltage source, the phase of which is the same as that of the UHF RFID signal applied between the plate element (19) and the first rod element (20).

6. Device for reading UHF RFID signals according to one of the preceding claims, characterized in that The feed network (31) is designed so that a UHF RFID signal having the same amplitude as the UHF RFID signal applied between the plate element (19) and the first rod element (20) can be applied between the plate element (19) and the second rod element (21) using a voltage source.

7. Device for reading UHF RFID signals according to one of the preceding claims, characterized in that The monopole antenna has third and fourth rod elements (22, 23) which are arranged perpendicular to the plate element (19) and are electrically conductive, and the third rod element (22) and the fourth rod element (23) are arranged at intervals of one quarter to three quarters of the wavelength (λ / 4 to ¾λ) of the UHF signal relative to each other, and a connecting line between the first and second rod elements (20, 21) and a connecting line between the third and fourth rod elements (22, 23) intersect at half of their routes, and the two connecting lines are arranged orthogonally relative to each other.

8. The device for reading UHF RFID signals according to claim 7, characterized in that: The third rod element (22) and the fourth rod element (23) are arranged relative to each other at half the wavelength (λ / 2) of the UHF signal.

9. The device for reading UHF RFID signals according to claim 7 or 8, characterized in that: The feed network (31) is designed so that a UHF RFID signal can be applied between the plate element (19) and the third rod element (22) and between the plate element (19) and the fourth rod element (23) using a voltage source, wherein the UHF RFID signal is phase-shifted by 180° compared to the UHF RFID signal applied between the plate element (19) and the first rod element (20).

10. The device for reading UHF RFID signals according to claim 7, 8 or 9, characterized in that: The feed network (31) is implemented so that a UHF RFID signal can be applied between the plate element (19) and the third rod element (22) and between the plate element (19) and the fourth rod element (23) using a voltage source, and the UHF RFID signal has the same amplitude as the UHF RFID signal applied between the plate element (19) and the first rod element (20).

11. Device for reading UHF RFID signals according to one of the preceding claims, characterized in that The vertically arranged rod elements (20-23) are implemented as a top-loaded monopole.

12. Device for reading UHF RFID signals according to one of the preceding claims, characterized in that The rod elements (20-23) have, at their ends facing away from the plate element (19), electrically conductive disk elements (24-27) which have a circular, oval, square or rectangular shape.

13. Device for reading UHF RFID signals according to one of the preceding claims, characterized in that The feed network (31) is designed to enable three of the four rod elements (20-23) to be short-circuited to the plate element (19) and to enable a UHF RFID signal to be applied between the plate element (19) and the remaining rod elements (20-23) using a voltage source.

14. Device for reading UHF RFID signals according to one of the preceding claims, characterized in that The radiation characteristic and / or the radiation direction of the at least one antenna can be varied, in particular periodically, by a voltage source.

15. Device for reading UHF RFID signals according to one of the preceding claims, characterized in that The plate element (19) has an electrically conductive border (28) on its plate edge pointing in the direction of the rod elements (20-23) and the height of the border (28) extends at least to the height of the ends of the rod elements (20-23) facing away from the plate element (19).

16. Device for reading UHF RFID signals according to one of the preceding claims, characterized in that The feed network (31) and / or the voltage source are integrated in a housing which is arranged on the side of the plate element (19) facing away from the rod elements (20-23).

17. Device for reading UHF RFID signals according to one of the preceding claims, characterized in that The antenna is integrated into the road surface in such a way that the side of the plate element (19) facing the rod elements (20-23) is oriented in the direction of the road surface of the road (11).

18. Device for reading UHF RFID signals according to one of the preceding claims, characterized in that Two, three, four or more reading devices (14) are arranged beside and / or above and / or on and / or in a route traveled by the mobile objects in order to detect a plurality of objects simultaneously.

19. A method for reading UHF RFID signals using a device according to at least one of claims 1 to 18, the UHF RFID signals being emitted by or reflected from at least one transponder (13) of an identification of a mobile object, preferably a motor vehicle (10), in particular a motor vehicle license plate, characterized in that The radiation characteristic of at least one antenna is changed so that it is directed in the direction of the moving object.

20. The method for reading UHF RFID signals according to claim 19, characterized in that: In order to change the radiation characteristic, the voltage between the plate element (19) and at least two rod elements (20, 21) of the antenna is changed.

21. The method for reading UHF RFID signals according to claim 19 or 20, characterized in that: By changing the radiation characteristics of the at least one antenna, UHF RFID signals from a transponder (13) close to the antenna and / or a transponder (13) far from the antenna are read.

22. Method for reading UHF RFID signals according to at least one of claims 19 to 21, characterized in that The radiation characteristic of the at least one antenna is changed so that the UHF RFID signal is read in a range of 360° around the antenna, in particular in the forward, backward, sideways or diagonal directions.

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