Patent Publication Number: US-2021175618-A1

Title: Transponder Device and Transponder System with Transponder Device

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
     The present application claims priority to EP Patent Application No. 19401052.6 filed Dec. 10, 2019, which is incorporated herein by reference in its entirety. 
     FIELD OF THE INVENTION 
     The invention relates to a transponder device with an antenna arrangement arranged on an antenna carrier, which is in particular formed as a film antenna, wherein the transponder device has a mounting substrate for fastening on a metallic support surface. The antenna arrangement has at least one inner antenna area arranged between the mounting substrate and the antenna carrier and an outer antenna area arranged on the antenna carrier opposite to the inner antenna area. Furthermore, the invention relates to a transponder system with such a transponder device. 
     BACKGROUND OF THE INVENTION 
     A transponder device with an antenna carrier for arranging a transponder is known from WO 2018/193309 A1, wherein the transponder device has an antenna arrangement which can be arranged around the antenna carrier. The antenna carrier is arranged in a housing, whose underside is formed by a mounting substrate for fastening the transponder device on the beverage steel barrel, which is used for transporting and storing beer. This kind of steel barrel, which is also called keg in terminology, is characterized by a special structure, so that a steel bladder, which is used to receive the liquid volume, both on the topside and on the underside, which are each formed as a curved bottom, has a circumferential steel barrel collar, which forms a stacking edge respectively and furthermore protects a valve centrally arranged on the topside of the bladder against mechanical damage from external influences. 
     Kegs are used in logistics circulation, wherein the barrels filled by several fillers are returned to the individual filler in circulation after they are emptied in an unsorted way, so that, for the respective filler, the empty kegs have to be assigned and redeliver to the external fillers. For this purpose, a reliable identification of the barrel is first of all necessary, which in particular takes into account the fact that the empty barrel regularly comes into a close spatial association with the respective filler, so that in practice it is proved that reading out the transponder data required for identification is difficult, wherein the transponder data is stored in a RFID transponder arranged at the barrel. 
     This problem is exacerbated by the fact that, due to the metallic design of the barrels, there is interference in the electromagnetic field required to read out the transponder data, which in existing practice has led to the RFID transponder, which is arranged at a steel barrel, being arranged as central as possible on the curved bottom of the bladder, so that in particular influences caused by the electromagnetic field can be largely excluded by the barrel collar surrounding the curved bottom. 
     Furthermore, the disadvantage of this exposed arrangement of the RFID transponders on the bladder has been proved that the transponders are often damaged, which leads to a failure. 
     Although the barrel collar obviously provides a better protection for the RFID transponder than the exposed arrangement on the bottom of the bladder, the arrangement of the RFID transponder on the inside of the barrel collar of the keg is not widespread in practice so far, because in this arrangement of the transponders, reliably reading out the transponder data is impossible due to the obvious influence of the barrel collar to the electromagnetic field. 
     SUMMARY OF THE INVENTION 
     The present invention is based on the object of proposing a transponder device or a transponder system of the transponder device which, when arranged on a metallic surface, enables the transponder data to be read out with sufficient reliability. 
     To achieve this object, the device according to the invention has the features of claim  1 . 
     According to the invention, at least the outer antenna portion of the antenna is arranged at an angle α 1  relative to the mounting substrate. 
     The invention is based on the knowledge that when the antenna is arranged on the metallic surface of the barrel, absolutely desired but also parasitic capacitances are formed due to a capacitive coupling, in particular between the inner antenna area facing the metallic surface of the barrel and the barrel surface. This applies all the more when the antenna is arranged on the angled metallic surfaces of the barrel collar, so that the resonance frequency of the antenna can be detuned due to the parasitic capacitances. 
     In contrast to an arrangement of the transponder on the curved bottom of the bladder of the metal barrel, i.e. in an area of the electromagnetic field that is largely unaffected by the barrel collar, the parasitic capacitances in the area of the barrel collar, which also causes interference in the electromagnetic field, have a much stronger effect to the resonance frequency, so that as a result of this there is an insufficient energy supply to the transponder via the electromagnetic field and thus the reading of the transponder is impaired. 
     As already emphasized, due to an inclined position of the outer antenna portion with respect to the mounting substrate, i.e. by adjusting an angle between the outer antenna portion and the mounting substrate, it is possible to offset parasitic capacitance caused by capacitive coupling between the inner antenna portion and the metallic surface of the barrel and thus a shift of the resonance point of the antenna can be reached. In addition, it has been proved that the radiation behavior of the antenna can also be positively influenced by adjusting the angle between the outer antenna area and the mounting substrate. 
     In the case of the transponder device according to the invention, the parasitic influences are counteracted by adapting a mechanical adjusting parameter. 
     An adjusting device is preferably provided for the defined adjustment of the angle, so that in particular by exchanging the adjusting device, different angles, i.e. relative inclined positions of the outer antenna area with respect to the mounting substrate, can be adjusted. 
     It is particularly preferred that the adjusting device is formed by an adjusting body arranged between the antenna carrier and the mounting substrate, which in a possible embodiment is formed in one piece at the antenna carrier so that the angle can be changed, for example, by exchanging the adjusting body. 
     The adjusting body is preferably designed as a component that is formed independently of the antenna carrier, so that one and the same antenna carrier is retained independent of the desired angle and the adjusting of an angle can be reached by exchanging the adjusting body. It is particularly preferred that the adjusting body is designed to be alterable, for example by the way that the adjusting body is provided with a mechanical adjusting device, such as in particular an adjusting screw. 
     In a preferred embodiment of the transponder device, at least one subsection of the inner antenna portion is arranged adjacent to the mounting substrate as a coupling section for a capacitive coupling with a metallic support surface. 
     If at least one subsection of the inner antenna area is arranged at an angle α 2  relative to the mounting substrate, a targeted influence on the parasitic capacitance formed between a metallic support surface and the transponder device is possible. 
     Preferably, the angle α 2  is equal to the angle α 1 , so that in a particularly simple embodiment of the transponder device, the antenna carrier is provided with two parallel surfaces for a correspondingly parallel arrangement of the outer antenna area and the inner antenna area, and only the wedge-shaped adjusting body is required for adjusting the angle. 
     If the inner antenna area has two subsections which are arranged on two opposite surfaces of the adjusting body, the adjusting body can simultaneously form a part of the antenna carrier. 
     The mounting substrate preferably at least partially forms a housing underside of a housing for receiving the antenna carrier provided with the antenna arrangement and the adjusting body, so that a particularly compact and at the same time against external mechanical influences protected design of the transponder device is possible. 
     The transponder system according to the invention has a transponder device according to the invention, wherein the mounting substrate is arranged on a metallic surface formed by an inside of a barrel collar of a steel barrel. 
     The mounting substrate is preferably arranged in such a way that a surface of the antenna carrier provided with the outer antenna area is arranged at an angle α 3  relative to the inside of the barrel collar. 
     The angle α 3  is preferably equal to the angle α 1 , so that the mounting substrate is in a substantially parallel arrangement with respect to the inside of the barrel collar. 
     It is particularly preferred that the angle α 1  is formed in a vertical plane running through the steel barrel, in such a way that the surface of the antenna carrier is arranged rising from a collar edge to a barrel bladder. This not only makes it possible to compensate for a parasitic capacitance caused by the barrel collar, but in addition, despite the arrangement of the antenna carrier on the barrel collar, an orientation of the antenna that is advantageous for effective coupling of the antenna to a reader is obtained. 
     An advantageous compensation of parasitic capacitances can already be achieved if the angle α 1  is formed in a vertical plane running through the steel barrel, in such a way that the surface of the antenna carrier is arranged sloping down from a collar edge to a barrel bladder. 
    
    
     
       DESCRIPTION OF THE DRAWINGS 
       In the following, advantageous embodiments of the present invention are explained in detail with reference to the drawings. In the drawings: 
       FIG. 1  shows a first embodiment of a transponder device; 
         FIG. 2  shows a second embodiment of a transponder device; 
         FIG. 3  shows a transponder system with a transponder device of a third embodiment provided on the inside of the barrel collar; 
         FIG. 4  shows the transponder system corresponding to  FIG. 3 , which has a transponder device of a fourth embodiment; 
         FIG. 5  shows the transponder system corresponding to  FIG. 3 , which has a transponder device of a fifth embodiment; 
         FIG. 6  shows the transponder system corresponding to  FIG. 3 , which has a transponder device of the fifth embodiment; 
         FIG. 7  shows the transponder system corresponding to  FIG. 3 , which has a transponder device of the fifth embodiment. 
     
    
    
     PREFERRED EMBODIMENTS OF THE INVENTION 
     FIG. 1  shows a transponder device  10  with a mounting substrate  11 , which is used to fasten the transponder device  10  on an essentially metallic surface, wherein the metallic surface can also be provided with a dielectric coating 
     In this case, the mounting substrate  11  simultaneously forms the bottom of a housing  12 , which is used to accommodate an RFID transponder  13 , which has a chip (not shown here) in contact with a UHF antenna arrangement  14 , preferably designed as a film antenna. The antenna arrangement  14  has an outer antenna area  15  which is connected to an inner antenna area  16  via a connecting section  17 . The outer antenna area  15  is arranged on an outer surface  18  of an antenna carrier  19 , which is arranged with an inner surface  20  parallel to the outer surface  18  on a wedge-shaped adjusting body  21 . The inner antenna area  16  is arranged on an inner surface  22  of the adjusting body  21  facing the mounting substrate  11 . 
     Although the adjusting body  21  is designed independently of the antenna carrier  19  in this case, in the illustrated embodiment the adjusting body  21  also takes on the function of an antenna carrier. 
     In contrast to the transponder device  10  shown in  FIG. 1 , in which the inner antenna area  16  extends continuously over the inner surface  22  of the adjusting body  22 ,  FIG. 2  shows a transponder device  25  of the same design as the transponder device  10  except for a two-part inner antenna area  27  of an antenna arrangement  26  such that the antenna arrangement  26  is open to the mounting substrate  11  with two inner subsections  28 ,  29  of the antenna device  26 , each of which allows a capacitive coupling of the antenna device  26  to a metallic support surface on which the mounting substrate  11  is arranged. As a further difference to the transponder device  10 , the transponder device  25  has an antenna carrier  23  with an adjusting body formed in one piece with the antenna carrier  23  for adjusting the angle α 1 . 
       FIG. 3  shows a transponder system with a transponder device  35  arranged on an inside  31  of a metallic barrel collar  32  of a steel barrel (not shown below) above a curved bottom  33  of a bladder  34  of the steel barrel. 
     The transponder device  35 , corresponding to the transponder device  10  shown in  FIG. 1 , has a housing  12  which accommodates an antenna carrier  36  and an adjusting body  37 . 
     An antenna arrangement  38  is arranged on the antenna carrier  36 , wherein the antenna arrangement comprises an outer antenna area  40  arranged on an outer surface  39  of the antenna carrier  36  and an inner antenna area  43  arranged between an inner surface  41  of the antenna carrier  36  and an outer surface  42  of the adjusting body  37 . 
     The outer antenna area  40  of the antenna arrangement  38  is arranged at an angle α 1  relative to the mounting substrate  11 , which corresponds to the angle α 3  between the outer antenna area  40  and the inside  31  of the barrel collar  32 . 
     Furthermore, an angle α 2  between the inner antenna area  43  and the mounting substrate  11  also corresponds to the angle α 1 . 
       FIG. 4  shows a transponder system with a transponder device  44 , which is arranged on the inner side  31  of the barrel collar  32  in accordance with the transponder device  35  and, like the transponder device  35  shown in  FIG. 3 , has an antenna carrier  36  and an adjusting body in a housing  12 . The transponder device comprises an antenna arrangement  45  which, unlike the antenna device  38  shown in  FIG. 3 , has an inner antenna area  46 , which is arranged between an inner surface  47  of the adjusting body  37  and the mounting substrate  11 . 
       FIG. 5  shows a transponder device  50  which, in accordance with the transponder devices  35  and  44  shown in  FIGS. 3 and 4 , has an adjusting body  37  with an antenna carrier  36  arranged thereon, so that an outer antenna area  51  of an antenna arrangement  52  implemented in the transponder device  50  is also arranged at the angle α 1  with respect to the mounting substrate  11  or at the angle α 3  with respect to the inside  31  of the barrel collar. 
     In contrast to the antenna arrangements  38  and  45  of the transponder devices  35  and  44 , however, an inner antenna area  53  of the antenna device  52  is arranged in such a way that it includes a subsection  54  arranged between the outer surface  42  of the adjusting body  37  and the inner surface  41  of the antenna carrier  36  as well includes a subsection  55  arranged between the inner surface  47  of the adjusting body  37  and the mounting substrate  11 , so that only the subsection  54  of the inner antenna area  53  is arranged at an angle α 2  with respect to the mounting substrate  11 . In addition, the antenna arrangement  52  shown in  FIG. 5  has a first antenna opening  56  formed at the adjusting body  37  between the subsections  54  and  55  and a second antenna opening  56  formed at the antenna carrier  36  between the outer antenna area  51  and the first subsection  54  of the inner antenna area  53 . 
     In a further embodiment,  FIG. 6  shows a transponder device  60  which, in accordance with the transponder devices  35 ,  44  and  50  shown in  FIGS. 3, 4 and 5 , has an antenna carrier  36 , wherein the transponder device  60  however has an adjusting body  63  formed with a first wedge portion  61  and a second wedge portion  62 . Overall, due to the configuration of the adjusting body  63 , an arrangement of an outer antenna area  64  of an antenna arrangement  65  is obtained, which corresponds to the arrangements of the outer antenna areas  40  and  51  of the transponder devices  35  and  50  with an angle α 1  of the outer antenna area  64  with respect to the mounting substrate  11 . 
     An inner antenna area  66  of the antenna arrangement  65  is arranged with a first subsection  67  between an inner surface  68  of the first wedge portion  61  and the mounting substrate  11 . A second subsection  69  of the inner antenna area  66  is arranged between the inner surface  41  of the antenna carrier  36  and an outer surface  70  of the second wedge portion  62  of the adjusting body  63 , wherein the first subsection  67  is connected to the second subsection  69  via an antenna shoulder  71  formed between the first and second wedge portions  61 ,  62   
     As  FIG. 6  shows, the result of this is that only the second subsection  69  is arranged at an angle α 2  with respect to the mounting substrate  11 , and the antenna arrangement  65  shown in  FIG. 6  only has an antenna opening  72  formed at the antenna carrier  36 . 
       FIG. 7  shows in an embodiment a transponder device  80  with an adjusting body  37  rotated by 180° with respect to the transponder devices  35 ,  44 ,  50  and  60 , in such a way that an outer antenna area  81  of an antenna arrangement  82  arranged on the outer surface  39  of the antenna carrier instead of sloping down from the bladder  34  with respect to the barrel collar  32 , as in the case of the transponder systems shown in  FIGS. 3 to 7 , the outer antenna area  81  is arranged rising from the bladder  34  with respect to the barrel collar  32 .