WO2013034809A1

WO2013034809A1 - Rfid reader

Info

Publication number: WO2013034809A1
Application number: PCT/FI2012/050868
Authority: WO
Inventors: Hannu Heino; Teemu Ainasoja; Anna Nummi; Sami Heino; Toni Heijari; Vesa Honkaniemi; Mikko Lähteenmäki; Jorma Lalla; Jessica SÄILÄ
Original assignee: Nordic Id Oy
Priority date: 2011-09-09
Filing date: 2012-09-07
Publication date: 2013-03-14
Also published as: FI20115883L; FI20115883A0

Abstract

In accordance with an example embodiment of the present invention, a radio frequency identification (RFID) device comprises a first part (27) having an antenna (27), wherein the antenna is concentrating its radiation power in a main beam propagating in a particular direction (A). The RFID device further comprises a second part (21 ) that is configured to form a body of a portable device and it comprises a transceiver being connected to communicate with the antenna (27). The RFID device further comprises coupling means (25) that is configured to movably couple the first part (27) and the second part (21). The coupling means (25) is configured to move the first part (27) in relation to the second part (21) to the position, in which the antenna is oriented to transmit and receive radio signals to and from a radio frequency identification tag in the direction (A) where the main beam is directed towards the radio frequency identification (RFID) tag.

Description

RFID reader

TECHNICAL FIELD

The present application relates generally to automatic identification technologies, and more specifically to portable radio frequency identification (RFID) readers.

BACKGROUND

A conventional RFID system consists of a reader with an antenna, a tag with an antenna and a host computer. The reader's antenna transmits radio signals to activate the tag and receives radio signals to read data from the tag and transmits radio signals to write data to the tag. When the tag passes through the electromagnetic waves generated by the reader's antenna, the tag's antenna detects the reader's activation signal. The reader decodes the data encoded in the tag's microchip and the digital data is passed to the host computer for processing according to the needs of a particular application. The maxi- mum distance across which the reader and the tag can effectively communicate is called the read range of the reader.

Conventionally, in a portable RFID device the antenna is in a fixed configuration with respect to the device. The antenna can be molded or otherwise integrated into the body of the RFID device or it can be fixedly attached the body of the device so that it protrudes from the body. Also detachable external antenna devices can be connected to the body of the RFID device providing a fixed configuration with respect to the body of the device. These kinds of antennas are positioned in a static manner resulting impractical form factor related problems, e.g. the bulkiness of the protruding antenna can result the device banging into objects and being clumsy when the device is used to scan RFID tags. On the other hand where the antenna is integrated into the housing of the RFID device, the efficiency of RFID scanning can also be impaired due to difficulties in directing the antenna effectively at the RFID tag target. Thus more power and time can be needed for scanning. The radiation power of the reader's antenna must be sufficiently high to meet requirements of efficient and reliable operation at appropriate operational conditions such as used radio frequency and read range between the reader and the tag. The operational conditions weigh heavily on a size and shape of the antenna. The antenna of hand-held readers incorporated into the body of the reader impose size constrains on the antenna, and therefore the read range of hand-held readers is relatively small. To meet the requirements an external dedicated antenna with specified physical dimensions is fixed or detachably connected to the body of the reader.

The antenna size and gain are proportional so that the higher the gain in decibels on the antenna the bigger the antenna has to be. The RFID antenna propagates the wave in both vertical and horizontal dimensions, and different vertical and horizontal radiation planes of the wave are used to provide differ- ent radiation patterns for reading the tags. The tags of interest are likely to be located in any direction with respect to the reader.

The read range relates also to the relative orientation of the antennas of the reader and the tag. The maximum read range is believed to be achieved when the antennas are substantially parallel with respect to each other. The relative- ly small read range requires the user of the hand-held reader to orient the reader so that the antenna is substantially parallel to the tag being communicated. The hand-held readers often are provided with connectors to connect the reader to an external antenna.

Hand-held readers often are used in applications where the user moves from item to item to read/write the tags attached to the items. The need to repeatedly position the reader device at a particular orientation when reading the tags can reduce the efficiency and speed with which the user can progress from tag to tag.

Fig 1 a shows a conventional hand-held RFID device 1 1 comprising a user in- terface 13, e.g. a display and/or a keyboard, and an integrated antenna 18a inside the casing of the device 1 1 . The dimensions of the device 1 1 are typically suitable for taking a grip by the user's hand and the dimensions are adapted to be such that the side "z" is longer than the side "y" and the side "y" is longer than the side "x". In operation mode the user must have easy access to the user interface 13. When the user is holding the device 1 1 in the operation mode, the RFID radiation direction, i.e. reading direction, is oriented to leave the device 1 1 to an opposite direction (arrow direction A) than where the user is standing. This means that the integrated antenna 18a is typically located at an end of the device 1 1 having dimensions "x" and "y", when the size and therefore the power of the antenna 18a remain rather modest. This limits the radiation power and the reception sensitivity of the antenna 18a. Especially the performance in the polarization level of the dimension "x" is poor. Figs 1 b and 1 c show arrangements how the small dimension "x" of fig 1 a can be compen- sated by inserting fixed or detachable external antennas 18b, 18c to the body of the RFID device 1 1 . Using such antennas 18b, 18c that protrude outside the dimensions of the device 1 1 , then also the smallest dimension "x" of the device 1 1 can be replaced by the longer dimension "h" of the protruding antenna 18b, 18c. However such protruding part from the hand-held device 1 1 is impractical and makes the device 1 1 more difficult to carry and the bigger size of the device 1 1 makes it more space-consuming in storage locations and transportation. Also, optimal orientation of the antenna suffers because the user has to control the orientation of the antenna by moving the whole device 1 1 having clumsy fixed structures. In figs 1 a-1 c the arrow A depicts the optimal direction of the radiation power from the antenna 18a, 18b, 18c.

To achieve more effective use of power in RFID scanning it is required to control the radiation direction of the reader's antenna. Thus, for example, where only a certain amount of power is available for scanning in the RFID device, the user can be required to manipulate or orient the RFID device so as to more effectively transmit and receive RFID information during scanning. The impractical form factor of the hand-held RFID device comprising the reader and at least one antenna can make this user manipulation and orientation more cumbersome.

Moreover, if the RFID device uses an antenna which radiates radio wave in a single direction and data of RFID tags only located at a side in a radio wave direction of such an antenna can be read out. Thus, the user has to manipulate the RFID device into more efficient positions so as to transmit and/or receive data to and/or from the RFID tag in order to, e.g. read, write, update, erase, query, or other such way to access the tag data. SUMMARY

Various aspects of examples of the invention are set out in the claims.

According to a first aspect of the present invention, a radio frequency identification (RFID) device comprises a first part having an antenna, wherein the antenna is concentrating its radiation power in a main beam propagating in a par- ticular direction. The RFID device further comprises a second part that is configured to form a body of a portable device and it comprises a transceiver being connected to communicate with the antenna. The RFID device further comprises coupling means that is configured to movably couple the first part and the second part. The coupling means is configured to move the first part in relation to the second part to the position, in which the antenna is oriented to transmit and receive radio signals to and from a radio frequency identification tag in the direction where the main beam is directed towards the radio frequency identification (RFID) tag. According to a second aspect of the present invention, a method comprises steps of receiving an indication from the radio frequency identification tag about its location, controlling orientation of the antenna according to the received indication so that said antenna is concentrating its radiation power in a main beam propagating in a particular direction, directing the main beam radi- ated by the antenna towards the radio frequency identification tag, and transmitting and receiving radio signals to and from the radio frequency identification (RFID) tag.

According to a third aspect of the present invention, a radio frequency identification system comprises a radio frequency identification (RFID) tag configured to communicate with an transceiver, a first part having an antenna, wherein said antenna concentrates its radiation power in a main beam propagating in a particular direction, a second part configured to form a body of a portable device and comprise a transceiver being connected to communicate with said antenna, and coupling means configured to movably couple the first part and the second part and move the first part in relation to the second part to the position, in which the antenna is oriented to transmit and receive radio signals to and from the radio frequency identification (RFID) tag in the direction where the main beam is directed towards the radio frequency identification (RFID) tag. According to a third aspect of the present invention, a computer program product comprises code for receiving an indication from the radio frequency identification tag about its location, code for controlling orientation of the antenna according to the received indication so that said antenna is concentrating its radiation power in a main beam propagating in a particular direction, code for directing the main beam radiated by the antenna towards the radio frequency identification tag, and code for transmitting and receiving radio signals to and from the radio frequency identification tag, when the computer program is run on a processor.

The RFID device, system, method and computer program according to the in- vention provides optimal orientation of the antenna in the reading direction. Therefore, the inventory operation can be carried out efficiently.

The RFID device, system, method and computer program according to the invention enables optimal antenna dimensions to ensure efficient access to the RFID tag. Optimal design of antenna dimensions also enables to propagate radio waves polarization independently.

The RFID device, system, method and computer program according to the invention has a space-saving form factor when not in use and therefore it facilitates storage and transportation of the portable device.

BRIEF DESCRIPTION OF THE DRAWINGS For a more complete understanding of example embodiments of the present invention, reference is now made to the following descriptions taken in connection with the accompanying drawings in which:

Figures 1 a-1 c depict antenna structures in hand-held RFID devices according to the prior art, Figures 2a-2b depict some exemplary RFID devices according to an embodiment of the invention,

Figures 3a-3b depict some exemplary RFID devices according to an embodiment of the invention,

Figure 4 depicts an exemplary RFID device according to an embodiment of the invention,

Figure 5 depicts an exemplary radiation pattern radiated by an RFID device according to an embodiment of the invention,

Figure 6 depicts a block diagram of a system according to an embodiment of the invention, and Figure 7 depicts a flow diagram of a method according to an embodiment of the invention.

DETAILED DESCRIPTON OF THE DRAWINGS

An example embodiment of the present invention and its potential advantages are understood by referring to Figs 1 through 7 of the drawings.

Figs 2a and 2b depict an example of portable radio frequency identification (RFID) device comprising a main part 21 that forms a body of the device and another part that forms an antenna part comprises at least an antenna element 27. The body part 21 of the device has preferably dimensions suitable for grip- ping by the user's hand. The device comprises coupling means 25 which is configured to couple the main part 21 and the antenna part so that the latter part is able to move in relation to the main part 21 . The dimensions of the antenna part can be selected so that the size and shape of the antenna element 27 is optimal. The main part 21 of the device preferably comprises at least a transceiver that is connected to communicate with the antenna element 27 of the antenna part. Alternatively, the antenna part comprises a transceiver. The RFID reader/writer device typically comprises at least the antenna element, transceiver and decoder.

Fig 2a shows the device in transport and storage configuration, where for ex- ample the antenna part is folded so that it is flat against the body 21 (the main part) of the device to form a very compact form factor. Fig 2b depicts the device in operational configuration, where the antenna part is freely foldable in relation to the body 21 of the device so that the angle between the foldable antenna part and the body part 21 can be anything starting from zero to 180 de- grees and more. Different exemplary positions of the antenna part comprising antenna element 27 are shown by dotted lines positions 27a, 27b and 27 c. The angle between the dotted lined position 27c of the antenna part and the body part 21 is more than 180 degrees. An arrow marked by R relates to the direction of the rotation angle of the antenna part in relation to the coupling means 25. In this example the antenna part comprising the antenna element 27 can be seen to rotate around an axis that is perpendicular to the paper surface.

The antenna element 27 of the antenna part emits radio signals so that it concentrates its radiation power in a main beam that is propagating in a particular direction. The coupling means 25 is configured to move the antenna part in relation to the main part 21 to the position, in which the antenna element 27 is oriented to transmit and receive radio signals to and from a target. When the user is holding the device in the operation mode, the RFID radiation direction, i.e. reading direction, is oriented to leave the antenna element 27 to a direction (arrow direction A) which is opposite to the position where the user is standing as shown in fig 2b. Due to foldable antenna part comprising the antenna element 27 it is easy for the user to orient the radio signals in the direction where the main beam of the radiation is directed towards the target such as the radio frequency identification (RFID) tag. This can be accomplished by the user folding the antenna part in relation to the body 21 , the user moving the whole device, or the user moving the whole device together with folding the antenna part in relation to the body 21 . The body 21 of the device can also be fixedly inserted, e.g. in the movable trolley, and then the antenna part in relation to the body 21 is foldable in a desirable way by the user or automatically.

Figs 3a and 3b depict another example of portable radio frequency identification (RFID) device comprising a main part 31 that forms a body of the device and another part that forms a cover part 32 that comprises at least an antenna element 37. The cover part 32 may also comprise a display 39. In this case the viewing direction (arrow B) of the display 39 and the radiation or reading direction (arrow A) of the antenna 37 are preferably directed to opposite directions from opposite sides of the cover part 32 with respect to each other. The body

31 of the device or the cover part 32 preferably comprises at least a transceiver that is connected to communicate with the antenna element 37 of the cover part 32. The device comprises coupling means 35 which is configured to couple the main part 31 and the cover part 32 so that the latter part is able to move in relation to the main part 31 .

Fig 3a shows the device in transport and storage configurations, where for example the cover part 32 is folded so that it is flat against the body 31 of the de- vice, and in Fig 3b the device in operation configuration, where the cover part

32 is freely foldable in relation to the body 21 of the device. An arrow marked by R relates to the rotation angle of the cover part 32 in relation to the coupling means 35, e.g. hinge joint.

In one embodiment of the invention a portable radio frequency identification (RFID) device comprises indication reception means and controlling means, and optionally also indication displaying means. Indication reception means is configured to receive an indication of a location of the radio frequency identification (RFID) tag with which the antenna element 37 is able to wirelessly communicate with. The indication of the tag location can be used as a basis for determining the orientation of the antenna element 37 and therefore the orientation of the cover part 32 in relation to the body 31 so that the radiation direction from the antenna element 37 is aligned to the RFID tag optimally. Preferably, the antenna element 37 is disposed in the cover part 32 so that the radiation direction from the element 37 is perpendicular to the surface of the cover part 32 as shown with the arrow A in Fig 3b. The indication reception means may include in the antenna element 37, transceiver or it can be e.g. a magnetic or optical receiver component in the body 31 or in the cover part 32. The controlling means of the RFID device is electrically connected to the indication reception means and the coupling means 35 and/or to the antenna element 37 in the cover part 32. The controlling means of the RFID device can be used to control the orientation of the cover part 32 as a response to the indication received by the indication reception means from the tag. In this way the cover part 32 comprising the antenna element 37 is foldable in relation to the body 21 automatically. The indication displaying means is electrically connected to the indication reception means and can display the location indication information for example on the display 39 of the RFID device. Based on the displayed location indication by the indication displaying means the user may place the device and/or fold the cover part 32 in a desired direction and position. The advantage of the indication of the RFID tag location is that it provides for the user a direct display what is the optimal direction and therefore facilitates orientating the antenna element 37 towards the RFID tag.

Fig 4 depicts another example of portable radio frequency identification (RFID) device comprising a body part 41 of the device and a cover part 42 that comprises at least an antenna element 47. The cover part 32 may also comprise a display 49 on the opposite side in relation to the antenna 47 as shown in a dashed reference sign 39. The coupling means 45 comprises in addition to the coupling means 35 shown in Fig 3b a vertical pivot means for pivoting or rotating the cover part 42 vertically in relation to the body part 41 so as to orientate the antenna element 47 towards the RFID tag. In this example the cover part 42 is firstly foldable, e.g. from a dash lined position 42a to a dash lined position 42b, horizontally (arrow R) in relation to the body part 41 of the device and then secondly rotatable around the vertical axis 44 vertically (arrow W) in relation to the body part 41 of the device. The device is shown in transport and storage position by the dash lined position 42a. However, according to another example the coupling means 45 is configured to allow the cover part 42 to be folded horizontally (arrow R) so that the side of the cover part 42 comprising the display 49 is against the side of the body part 41 in transport and storage position. In this case the dimensions of the cover part 42 preferably follow the dimensions "x" and "y" of the side of the cover part 42. A locking mechanism can be provided in order to secure the cover part 42 in its rest position beside the body part 41 of the device. In this example the cover part 42 may rotate around the vertical axis 44 (arrow W) as well. In this example, the cover part 42 can also be the antenna element 27 as shown in Figs 2a-2b.

The antenna element 27 or the cover part 32, 42 comprising antenna element 37, 47 is coupled to the body part 21 , 31 , 41 of the RFID device through the coupling means 25, 35, 45 so that the antenna part 27 or the cover part 32, 42 may be moved relative to the horizontal plane of the body part 21 , 31 , 41 . The coupling means 25, 35, 45 may comprise for example a hinge means for folding or hinging the antenna 27 or cover part 32, 42 horizontally (arrow R) in relation to the body part 21 , 31 , 41 or a pivot means for pivoting or rotating the antenna 27 or cover part 32, 42 horizontally (arrow R) in relation to the body part 21 , 31 , 41 . The coupling means 25, 35, 45 may comprise for example a rotational hinge, a pivot, a ball-joint connector, a universal hinge or other such component providing hinged, pivoted or rotational movement, or any combination of the mentioned. Preferably the coupling means 25, 35, 45 causes the cover part 32, 42 to remain in any position in relation to the body part 31 , 41 until moved by the user. The coupling means 25, 35, 45 may further comprise a vertical pivot means for pivoting or rotating the cover part 32, 42 or solitary antenna element 27 vertically (arrow W) in relation to the body part 21 , 31 , 41 . The coupling means 25, 35, 45 may comprise elements allowing the horizontal and vertical pivot means to slide in relation to each other. For example, the vertical pivot means can slide along the horizontal pivot means so as to orientate the antenna element 27, 37, 47 towards the RFI D tag.

Fig 5 depicts an exemplary 2D radiation pattern of an antenna 57 that can be used as an antenna element in the RFID device according to an embodiment of the invention. For any direction relative to the center of the antenna 57, the distance to the pattern surface represents the relative power density radiated by the antenna 57 in that direction. A main lobe 53 is formed in the direction A which is the radiation direction of the antenna 57. Side lobes 54 are also formed to other directions. In this example, the antenna 57 concentrates its radiated power in a main beam propagating in the direction A formed by the main lobe 53. The cover part 32, 42 or the antenna element 27 comprising the antenna 57 is moved in relation to the main part 21 , 31 , 41 to the position, in which the antenna 57 is oriented to transmit and receive radio signals to and from the RFID tag in the direction A where the main beam is directed towards (aligned with) the RFID tag. For example, the main beam is directed towards the RFID tag, when at a direction relative to a center of the antenna 57, the distance within the surface of the main beam represents the radiation power radiated by the antenna 57 in that direction. The cover part 32, 42 and integrated antenna element 57 can be aligned with the RFID tag to substantially maximize the read range of the RFID device. To achieve maximum read range, the user must align the RFID device so that the antenna 57 of the RFID device is substantially parallel to an antenna (reference 661 in Fig 6) of the RFID tag when the RFID tag is communicated. Antennas 57 are available in a variety of shapes and sizes depending on the application. The antenna 57, preferably directional antenna, is applicable in antenna elements 27, 37, 47, in all embodiments of the invention.

Fig 6 depicts an exemplary block diagram of a system according to an embodiment of the invention. The system comprises an RFID reader/writer device having a body part 61 and a cover part 62, and an RFID tag 66 attached to an item having antenna 661 and a memory or microchip 662. The RFID reader/writer device typically comprises transceiver and decoder 613 which are communicatively coupled to the controller 61 1 and antenna 67. The controller 61 1 is configured to control the radiation direction of the antenna 67 by controlling a coupling means 65 according to received instructions. The RFID reader/writer can read out data or write data from or to RFID tags 66 which are located along the radiation direction of the reader's antenna 67. The device further comprises coupling means 65 which is configured to couple the body part 61 and the cover part 62 so that the latter part is able to move in relation to the body part 61 to a position, in which the reader's antenna 67 is oriented to transmit and receive radio signals to and from the RFID tag 66 in the direction where the main beam is directed towards the RFID tag 66. Preferably, in this position the reader's antenna 67 is substantially parallel to the tag's antenna 661 . The coupling means 65 is configured to move the cover part 62 comprising the antenna element 67 horizontally and/or vertically in relation to the body part 61 as earlier discussed in this application.

In one embodiment of the system according to the invention a portable radio frequency identification (RFID) device comprises indication reception means as a separate component (not shown) or as part of the transceiver 613, antenna 67 or other reception component, and optionally also indication displaying means. The RFID tag 66 may comprise an indication transmission means 663 which transmits magnetic, electric or optical indication signals as an indication of its location, i.e. location of the RFID tag 66. The indication transmission 663 means may include or may be the antenna 661 of the RFID tag 66. The indication reception means is configured to receive this magnetic, electric or optical indication signals as an indication of a location of the RFID tag with which the reader's antenna 67 is able to wirelessly communicate with. The controller 61 1 is electrically connected to the indication reception means and configured to receive indication signal. For example, this indication signal is proportional to the signal strength of the radiation power received (backscattered) from the antenna 661 of the RFID tag 66 or the separate indication means 663 of the RFID tag 66. Based on the received indication signal the controller 61 1 may instruct the cover part 62 to move in relation to the body part 62.

The cover part 62 may also comprise a display 39 which may act as the indication displaying means for the user. In addition to the display 69, a user interface of the RFID device may comprise an input device 614 such as a keypad, microphone, tablet, touch screen or combination any of them, although other input devices can also be utilized. The input devices 614 can be electrically connected to the controller 61 1 and memory 612.

Fig 7 depicts an exemplary flow diagram of a method according to the invention. For example, the method comprises a step 71 1 of enclosing or integrating the antenna 67 in the cover part 62 of the RFID device and a step 713 of en- closing a transceiver and decoder 613 in the body part 61 of the RFID device. Alternatively, the transceiver and decoder 613 can be enclosed in the cover part 62 together with the antenna 67. Then in an optional step 715 the user receives a location indication from the RFID tag, and in a step 717 the cover part 62 and the antenna 67 enclosed therein is oriented according to the location indication by the user or automatically under the control of the controller 61 1 so that the antenna 67 is concentrating its radiation power in a main beam propagating in a particular direction. Alternatively, in step 717 the cover part 62 and the antenna 67 therein is oriented according to the user's eyesight so that the antenna 67 is concentrating its radiation power in a main beam propagat- ing in a particular direction. In a step 719 the cover part 62 is moved with respect to the body part 61 so as to provide a direct main beam towards the antenna 661 of the RFID tag 66. Then in a step 721 the transceiver 613 of the RFID device may access radio connection to the memory chip 662 of the RFID tag via the antenna 67 and the antenna 661 . The accessing may include e.g. read out, write to, update, erase, query, or other such way access the data in the microchip 662 of the RFID tag 66.

Without in any way limiting the scope, interpretation, or application of the claims appearing below, a technical effect of one or more of the example embodiments disclosed herein is to provide optimal orientation of the reader's an- tenna in the reading direction. Therefore, the inventory operation can be carried out efficiently. Another technical effect of one or more of the example embodiments disclosed herein is to enable various antenna dimensions to ensure efficient access to the RFID tag. Optimal design of antenna dimensions also enables that radio waves propagate polarization independently. Another tech- nical effect of one or more of the example embodiments disclosed herein is to facilitate storage and transportation of the portable device.

Embodiments of the present invention may be implemented in software, hardware, application logic or a combination of software, hardware and application logic. The software, application logic and/or hardware may reside on the memory of the RFID device or the database being connected to the RFID system. In an example embodiment, the application logic, software or an instruction set is maintained on any one of various conventional computer-readable media that can contain, store, communicate, propagate or transport the instructions for use by or in connection with an instruction execution system or device, such as a controller, with one example of a controller described and depicted in Fig 6. A computer-readable medium may comprise a computer- readable storage medium that may be any media or means that can contain or store the instructions for use by or in connection with an instruction execution system, apparatus, or device, such as a computer. If desired, the different functions discussed herein may be performed in a different order and/or concurrently with each other. Furthermore, if desired, one or more of the above-described functions may be optional or may be combined. Although various aspects of the invention are set out in the independent claims, other aspects of the invention comprise other combinations of features from the described embodiments and/or the dependent claims with the features of the independent claims, and not solely the combinations explicitly set out in the claims. It is also noted herein that while the above describes example embodiments of the invention, these descriptions should not be viewed in a limiting sense. Rather, there are several variations and modifications which may be made without departing from the scope of the present invention as defined in the appended claims.

Claims

1 . A radio frequency identification device, comprising

- a first part having an antenna, said antenna concentrating its radiation power in a main beam propagating in a particular direction, - a second part configured to form a body of a portable device and comprising a transceiver being connected to communicate with said antenna,

- coupling means configured to movably couple the first part and the second part and move the first part in relation to the second part to the position, in which the antenna is oriented to transmit and receive radio signals to and from a radio frequency identification tag in the direction where the main beam is directed towards the radio frequency identification tag.

2. A device according to claim 1 , wherein the coupling means comprises a hinge means for folding or hinging the first part horizontally in relation to the second part.

3. A device according to claim 1 , wherein the coupling means comprises a pivot means for pivoting or rotating the first part horizontally in relation to the second part.

4. A device according to any of claims 1 -3, wherein the coupling means further comprises a vertical pivot means for pivoting or rotating the first part verti- cally in relation to the second part.

5. A device according to any of claims 1 -4, wherein dimensions of the antenna define the size and the form factor of the first part.

6. A device according to any of claims 1 -5, wherein the first part further comprises a display.

7. A device according to any of claims 1 -6, wherein the display is on the opposite side of the first part than the antenna and the main beam propagating from the antenna is oriented to the opposite direction in relation to the display direction from the display.

8. A device according to any of claims 1 -7, comprising controlling means in the first or second part, wherein the controlling means is configured to control the orientation of the first part as a response of an indication received from the radio frequency identification tag, said controlling means being electrically connected with the antenna and/or said coupling means.

9. A device according to any of claims 1 -8, wherein the main beam is di- rected towards the radio frequency identification tag, when at a direction relative to a center of the antenna, the distance within a surface of the main beam represents the radiation power radiated by the antenna in that direction.

10. A device according to any of claims 1 -9, wherein the coupling means is configured to move the first part in relation to the second part to the position, in which the antenna is substantially parallel to an antenna of the radio frequency identification tag.

1 1 . A device according to any of claims 1 -10, wherein the coupling means is configured to move the first part in relation to the second part to the position, in which the first part is substantially parallel to the second part.

12. A method comprising

- receiving an indication from a radio frequency identification tag about its location,

- controlling orientation of the antenna according to the received indication so that said antenna is concentrating its radiation power in a main beam propa- gating in a particular direction,

- directing the main beam radiated by the antenna towards the radio frequency identification tag, and

- transmitting and receiving radio signals to and from the radio frequency identification tag.

13. A method according to claim 12, comprising

- enclosing the antenna in a first part,

- enclosing the transceiver in a second part, said second part forming a body of a portable device, - movably coupling the first part and the second part so that the first part moves in relation to the second part to the position, in which the antenna is oriented to transmit and receive radio signals to and from a radio frequency identification tag in the direction where the main beam is directed towards the radio frequency identification tag.

14. A radio frequency identification system, comprising

- a radio frequency identification tag configured to communicate with an transceiver,

- a first part having an antenna, said antenna concentrating its radiation power in a main beam propagating in a particular direction,

- a second part configured to form a body of a portable device and comprising a transceiver being connected to communicate with said antenna, and

- coupling means configured to movably couple the first part and the second part and move the first part in relation to the second part to the position, in which the antenna is oriented to transmit and receive radio signals to and from the radio frequency identification tag in the direction where the main beam is directed towards the radio frequency identification tag.

15. A system according to claim 14, wherein the radio frequency identification tag is configured to give an indication about its location and the coupling means is configured to receive orientation instructions based on said indication.

16. A computer program product comprising

- code for receiving an indication from the radio frequency identification tag about its location, - code for controlling orientation of the antenna according to the received indication so that said antenna is concentrating its radiation power in a main beam propagating in a particular direction,

- code for directing the main beam radiated by the antenna towards the radio frequency identification tag, and - code for transmitting and receiving radio signals to and from the radio frequency identification tag,

when the computer program is run on a processor.