Multidirectional walkthrough antenna

#This invention relates to wireless devices, and more particularly, to an antenna attached to a remote sensing apparatus or interrogator for use in detecting wireless communications devices such as radio frequency identification (RFID) tags or transponders affixed to livestock for identification of an animal as it passes proximate to the antenna.

#Wireless communications devices, including wireless memory devices for storing and transmitting data such as RFID transponders or tags are generally known in the art. Such transponders are particularly used in the livestock industry for such uses as tracking and accounting for animals being shipped and, for distinguishing between animals, such as upon introduction to a herd or feedlot. The devices are also useful in tracking, such as used in connection with salmon and other fish for scientific and environmental purposes.

#However, difficulties have existed for some time with electronically reading identification tags mounted on livestock or fish. First, the transponder to be monitored is passive and is typically implanted within the fish or animals where the final position or orientation of the implanted transponder cannot be controlled. Alternatively, the transponder is externally affixed to an animal's ear, such as with livestock, and the orientation of the transponder varies with the movement of the animal's head. In this regard, to optimize reading of a transponder, the transponder antenna should be properly aligned with the fields generated by the interrogator antenna. Also, environmental conditions need to be considered that could adversely affect orientation of the transponder relative to the antenna, such as water currents in the case of fish, or rain, wind and sun in the case of outdoor livestock. Further, for optimum activation and communication, an adequate electromagnetic field must be generated by the interrogation device or interrogation antenna. Thus, weak magnetic interrogation fields and/or poorly orientated transponders can inhibit accurate interrogation of a transponder.

#For a fuller understanding of the invention, reference is made to the following description taken in connection with accompanying drawings, in which:

#FIG. 1 is a top planar view of the antenna of the present invention showing the inner and outer antenna coils formed in the flexible housing;

#FIG. 2 is an isometric view of the flexible housing of the antenna folded to form a walkthrough passage through which the livestock to be identified may pass;

#It should be understood that the drawings are not necessarily to scale. For example, the lines representing the magnetic fields are for illustration purposes only, and are not intended to be a complete representation of the magnetic fields. In certain instances, details which are not necessary for an understanding of the invention or which render other details of the invention difficult to perceive may have been omitted. Also, it should be understood that the invention is not limited to the embodiment shown in the drawings.

#The present invention is directed to an antenna for use with interrogators for reading transponders such as ear tags that are attached to livestock. More particularly, the invention is directed to an antenna that is easily transportable and deployable, and provides multidirectional electromagnetic fields capable of reading a transponder regardless of the orientation of the transponder as it moves through the electromagnetic field.

#Referring now to FIG. 1, there is depicted a flexible, transportable antenna 10 in accordance with one embodiment of the present invention. Antenna 10 includes a relatively flat, flexible rectangular housing or mat 12, having short dimensions 14/14′ and long dimensions 16/16′. In other embodiments, not shown, mat 12 may be in any geometric configuration which will provide the multidirectional electromagnetic field coverage described hereinafter, such as oval or square, which other embodiments are considered to be within the scope of the invention.