Patent Publication Number: US-2010109871-A1

Title: Rfid system and method for the same

Description:
BACKGROUND 
     The subject matter disclosed herein relates generally to radio frequency identification (RFID) systems, and, more particularly, to a standalone antenna for a low frequency asset-tracking RFID system to enhance read ranges of passive RFID tags. 
     Identifying and tracking assets is a significant expense for a business that handles significant volumes of inventory. For example, inventory items that are brought to a storage facility must be identified, categorized and stored so that the items can be readily retrievable. Inventory items that are to be shipped from storage must again be identified to provide an accurate accounting of items remaining in storage. Additionally, entire inventories may need to be periodically re-counted to ensure that accounted inventory levels remain accurate over time despite occasional human error. Consequently, several man-hours of labor may be consumed solely in asset tracking. Similarly, in shipping applications, large quantities of different items may need to be counted, listed, checked, and manifests or declarations may need to be generated for the shipper, receiver, and customs authorities. 
     Radio frequency identification systems decrease the cost of asset tracking. An RFID system commonly includes an RF tag and an RF tag reader. An RF tag is capable of carrying a small amount of identification data related to an item to which it is attached. The tag may be either an active tag or a passive tag. In the case of a passive tag, the tag reader transmits an RF signal to a passive tag to identify an item. The RF signal energizes the passive tag, inducing the passive tag to transmit a return signal that carries the identification information embedded on the tag. By automating most of the asset tracking process, RFID technology provides a quicker, more accurate and less expensive method of tracking assets. 
     Items in the inventories are retrieved by a variety of industrial transport equipment such as a clamp-lift truck and forklift truck. There are many moving parts in industrial transport equipment such as lines, hoses, hydraulics for forks, and slip rings for clamps. When the transport equipment is used to retrieve an item, the moving parts of the transport equipment interfere with the read range of a passive tag attached to the item to be retrieved. This decreases the read range of the passive tag. The passive tag therefore may not be able to capture the RF signal from the tag reader, causing difficulty in tracking the items to be retrieved. 
     An ultra high frequency RFID system is generally employed to overcome the aforementioned issues in tracking the items. An ultra high frequency RFID system requires wiring of readers and antennas, and may even require several layers of antennas to capture all the items. However, wired configuration of the ultra high frequency RFID system is unable to get around moving parts of the industrial transport equipments. 
     Therefore, it would be advantageous to provide an improved RFID system that addresses the foregoing issues. 
     BRIEF DESCRIPTION 
     In accordance with one embodiment disclosed herein, a system for a radio frequency identification tag of a radio frequency identification system includes an antenna mounted on a respective piece of equipment and a power supply electrically coupled to the antenna. The antenna is configured to energize a radio frequency identification tag without contact for enhancing the read range of the radio frequency identification tag. 
     In accordance with another embodiment disclosed herein, an asset-tracking radio frequency identification system comprises radio frequency identification tags associated with assets, a radio frequency identification reader, an antenna mounted on a respective piece of equipment, and a power supply electrically coupled to the antenna. The antenna is configured to energize the radio frequency identification tags without contact for enhancing read range of the radio frequency identification tag. 
     In accordance with another embodiment disclosed herein, a method of enhancing read range of radio frequency identification tags of an asset-tracking radio frequency identification system comprises providing an antenna on equipment to energize a radio frequency identification tag without contact and providing a power supply electrically coupled to the antenna. 
    
    
     
       DRAWINGS 
       These and other features, aspects, and advantages of the present invention will become better understood when the following detailed description is read with reference to the accompanying drawings in which like characters represent like parts throughout the drawings, wherein: 
         FIG. 1  illustrates a block diagram of an asset-tracking radio frequency identification (RFID) system. 
         FIG. 2  illustrates a system for enhancing read range of RFID tags employed in an asset-tracking RFID system in accordance with aspects disclosed herein. 
         FIG. 3  illustrates an antenna with external power supply in accordance with aspects disclosed herein. 
         FIG. 4  illustrates a battery-powered antenna in accordance with aspects disclosed herein. 
         FIG. 5  illustrates a side view of a forklift truck with a system for enhancing read range of RFID tags in accordance with aspects disclosed herein. 
         FIG. 6  illustrates a side view of a clamp-lift truck with a system for enhancing read range of RFID tags in accordance with aspects disclosed herein. 
         FIG. 7  is a flowchart illustrating a method of enhancing read range of radio frequency identification tags of an asset-tracking radio frequency identification system in accordance with aspects disclosed herein. 
     
    
    
     DETAILED DESCRIPTION 
     Embodiments disclosed herein include a system and method for enhancing the read range of radio frequency identification (RFID) tags of an asset-tracking RFID system. The system includes an antenna mounted on a respective piece of equipment and a power supply for the antenna. The antenna energizes RFID tags without contact to enhance the read range of the tags. The system employed enhances the read range between about two units to five units. The system may be employed in various RFID applications such as, but not limited to, RFID systems used in transport facilities, shop facilities, and shipping applications or in any other environment that encounters similar interference conditions. As used herein, the term ‘read range’ of a tag is the distance from the tag over which the tag can draw enough energy from the reader to energize the tag. 
       FIG. 1  illustrates a typical asset-tracking RFID system  10  including passive RFID tags  12 . The passive RFID tags  12  are attached to assets  14  to be tracked in a warehouse. An RFID reader  16  transmits an RF signal  18  to a passive tag to identify an asset. The RF signal energizes the passive tag and induces the passive tag to transmit a return signal that carries the identification information embedded on the tag. Assets are tracked by this return signal and are then retrieved and hauled around the warehouse. Based on the assets&#39; size, shape and other handling requirements, appropriate pieces of equipment are used for retrieving and hauling the assets. In one embodiment, the equipment includes industrial transport equipment  20  such as a forklift truck or a clamp-lift truck, that are typically used to retrieve and haul assets in a warehouse. 
     The passive RF tags  12  typically include a read range  22 . In order to energize the tag  12 , it is desirable that the tag&#39;s read range  22  be within the range of the RF signal  18  from the reader  16  to draw enough energy. However, several factors affect the tag&#39;s read range  22 . For example, the industrial transport equipment  20 , especially, the movable parts of the industrial transport equipment such as lines, hoses, hydraulics for forks and slip rings for clamps may interfere with the read range  22  of the tag  12  by obstructing the tag&#39;s read range  22 . In addition, assets  14  themselves may interfere with the read range of the tag by obstructing and affecting the tag&#39;s read range. As a result, the read range  22  of the tag is decreased and the tag  12  may not be able to capture the RF signal  18 , causing difficulty in tracking the asset  14 . 
       FIG. 2  illustrates a system  30  for enhancing the read range of RFID tags employed in an asset-tracking RFID system  10 . The system  30  is a standalone unit and comprises an antenna  32  and a power supply  34  electrically coupled to the antenna  32 . The antenna  32  is mounted on the equipment, for example the industrial transport equipment  20 . The system can also be built into the equipment. In another embodiment, the system  30  can be employed with robotics used for moving assets in warehouses. The antenna  32  is configured to energize RFID tags  12  without contact by inductive coupling. When the industrial transport equipment  20  approaches an asset  14 , the antenna  32  energizes the tag  12  attached to the asset  14 . This will enhance the read range of the tag. The enhanced read range  36  of the tag  12  increases the probability for the RF signal  18  from the reader  16  to be transmitted to the tag  12  for drawing enough energy. Since the antenna  32  energizes the tag  12 , the RF signal  18  from the reader is dedicated to induce the tag  12  to transmit a return signal without the need for the RF signal  18  to energize the tag  12 . The enhanced read range  36  therefore facilitates in overcoming interference caused by the asset  14  or the movable parts of the industrial transport equipment  20 . 
       FIG. 3  illustrates an embodiment  40  of a system for enhancing read range of RFID tags. The system  40  comprises an antenna  42  including a loop structure and a power cord  44  connected to the antenna  42  for providing power supply. The power cord  44  can be plugged to a power outlet in a forklift truck or a clamp-lift truck to provide power supply to the antenna. While  FIG. 3  depicts a power cord with a plug end, other embodiments can be directly wired into the power generation system or battery of the piece of equipment. 
       FIG. 4  illustrates another embodiment  50  of a system for enhancing read range of RFID tags. The system  50  comprises an antenna  52  including a loop structure and a built-in power supply. In one embodiment, the built-in power supply comprises a battery or batteries  54 , or other energy source. 
     The loop structures of the antennas  42  and  52 , as shown in  FIGS. 3 and 4 , enable the system to be mounted at several locations on the industrial transport equipment without interfering with the movable parts of the industrial transport equipment. For example, the system can be mounted on the clamp of a clamp-lift truck without interfering with slip rings or hydraulics. The systems  40  and  50  of  FIGS. 3 and 4  therefore eliminate any need to redesign any part of the industrial transport equipment. 
       FIG. 5  illustrates a forklift truck  60  with the system  30  for enhancing the read range of passive tag  12  attached to asset  14 . The antenna  32  is mounted to the exterior of the forklift truck  60 , preferably near the fork  62 . The reader (not shown) can be placed in the driver cabin  64  of the forklift truck  60 . As discussed earlier, the loop structure of the antenna enables it to be mounted at several locations on the forklift truck. For example, the antenna  32  can be mounted on the fork  62  or on any projecting feature on the forklift truck. During the process of retrieving an asset  14 , the movable parts of the forklift truck, such as the fork and other hydraulics (not shown), or the asset itself may interfere with the read range of the tag. But the antenna  32  energizes the tag  12  attached to the asset  14  to enhance the read range of the tag, overcoming any interference. 
       FIG. 6  illustrates a clamp-lift truck  70  with the system  30  for enhancing the read range. The reader (not shown) can be placed in the driver cabin  74  of the clamp-lift truck  70 . The antenna  32  can be mounted at several locations on the clamp-lift truck  70  such as on the clamp  72  or any projecting feature of the clamp lift truck. The clamp-lift truck comprises movable parts such as the clamp  72 , slip rings (not shown) and other hydraulics. The process of retrieving an asset  14  with the clamp-lift truck comprises raising or lowering the clamp  72 , rotation of the clamp  72  depending on the orientation of the asset and clamping the asset. The movements of the clamp  72  and other hydraulics or the asset  14  itself may interfere with the read range of the tag  12  and decrease the read range of the tag  12 . Employing the system  30  with the clamp-lift truck  70  facilitates in overcoming such interference because the antenna  32  energizes the tag  12  attached to the asset  14  to enhance the read range of the tag  18 . 
       FIG. 7  illustrates a flowchart of a method  80  of enhancing read range of radio frequency identification tags of an asset-tracking radio frequency identification system. The method  80  comprises providing an antenna on a respective unit of equipment in step  82  and providing a power supply to the antenna in step  84 . The antenna is mounted on a respective unit of equipment. In one embodiment, the equipment comprises industrial transport equipment such as a forklift truck or a clamp-lift truck. As discussed above, the antenna includes a loop structure and can be mounted at several locations on the industrial transport equipment. In one embodiment, the power supply is provided to the antenna from the industrial transport equipment. In another embodiment, the power supply includes batteries. In step  86 , the antenna energizes an RFID tag attached to an asset when the industrial transport equipment is in the process of retrieving the asset. 
     The various embodiments of a system and method for an asset-tracking RFID system described above thus provide a way to enhance the read range of RFID tags. The system and method increase reliability of a reader and facilitate in overcoming interference caused by assets or movable parts of industrial transport equipment that are used to haul assets. 
     It is to be understood that not necessarily all such objects or advantages described above may be achieved in accordance with any particular embodiment. Thus, for example, those skilled in the art will recognize that the systems and techniques described herein may be embodied or carried out in a manner that achieves or optimizes one advantage or group of advantages as taught herein without necessarily achieving other objects or advantages as may be taught or suggested herein. 
     While only certain features of the invention have been illustrated and described herein, many modifications and changes will occur to those skilled in the art. It is, therefore, to be understood that the appended claims are intended to cover all such modifications and changes as fall within the true spirit of the invention.