Patent Application
20100109871
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.
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.
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:
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.
The passive RF tags 12 typically include a read range 22. In order to energize the tag 12, it is desirable that the tag'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'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's read range 22. In addition, assets 14 themselves may interfere with the read range of the tag by obstructing and affecting the tag'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.
The loop structures of the antennas 42 and 52, as shown in
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.
