in fig1 , there is depicted a system 10 for the common application of the use of rf signals 12 as a medium for recognizing multiple containers of merchandise stacked on a retail shelf , for example , employing a remote rfid reader 18 . in this figure , there are depicted two rfid - tagged cartons 14 and 16 of cigarettes ( known to container metallized foil ), the two cartons being aligned with one of the cartons 14 disposed between the other 16 of the cartons and a remote rfid reader 18 having an antenna associated therewith . in this situation , the rfid tag # 2 of the second carton will likely not be recognized by the reader due to the metallized foil in the cigarette packages of the first carton 14 blocking or distorting the rf from the reader . in this situation , if the rfid tags are associated with the individual cartons of cigarettes , the reader will consistently recognize rfid tag # 1 associated with the first carton 14 , but will recognize rfid tag # 2 only when there is an air gap 20 % greater than about one inch between the cartons . this same result has been observed when the cartons of cigarettes are palletized . that is , the rfid tags associated with those cartons most “ inner ” of the pallet are not recognized by the rfid reader . in fig2 , there are depicted three cartons 22 , 24 and 26 of cigarettes disposed on a retail display shelf 28 in side - by - side relationship . in accordance with one aspect of the present invention , the shelf is provided with an elliptical supplemental antenna 30 , 32 and 34 respectively , associated with each individual and / or row of cartons on the shelf . in this embodiment , each of the shelf antennas include a portion 36 thereof which is disposed directly beneath one of the cartons 22 on the shelf and a second portion 38 which projects out from under the same carton , whereby such second portion of the antenna is exposed for substantially uninterrupted access by rf generated signals 12 by a remote rfid reader 18 , and its associated antennae 19 . in this embodiment , the rf signals 12 emanating from the antenna 19 associated with the rfid reader 18 readily reach , and are picked up by , each of the supplemental antennas associated with the shelf and are transmitted to one or more tags 42 , 44 and 46 which are associated with the cartons of cigarettes . reverse transmission of rf from the tags to the reader takes place in like manner . the use of supplemental antennae associated with products stored on a shelf provide the advantage that the usual microchip in the rfid tag can be smaller , without a chip antennae , and less power consuming hence , having less expensive . this advantage is directly related to the near proximity of the supplemental antennae to the rfid tag . further , in this embodiment , the rf signal from the antennae 19 ; in combination with the supplement antennae 20 , 22 and 24 , can access tags on individual packages of cigarettes within a carton . in the embodiment depicted in fig2 , each of the antenna on the shelf may comprise an individual antenna associated with each of the cartons on the shelf or may be of a size and geometry sufficient to accommodate multiple ones of the cartons on the shelf . further , each antenna may be applied ( releasably or fixedly ) to the top surface 50 of the shelf by any of several conventional means . in one embodiment , the multiple antennas may be affixed to a strip of material , such as a strip of paper or paperboard or the like , and the strip itself may be applied to the top surface of the shelf . in the embodiment of the present invention depicted in fig3 and 4 , there is provided a plurality of individual antennas 52 ( typical ) affixed to one surface 54 of a conventional paper slip sheet 56 . individual ones 56 , 56 ′ and 56 ″ of the antenna - bearing slip sheets are designed to be inserted between rows 58 , 60 and 62 of cases 64 % product stacked on a pallet 66 , for example , as depicted in fig4 and / or between the bottom row 62 of cases and the pallet 66 itself . each slip sheet 56 , for example , itself may be formed from any material which does not materially interfere with the transmission of rf signals and which provides the normal function of a slip sheet . preferably the slip sheet material is transparent to rf signals , such as is corrugated paperboard . by this means , rf signals may be transmitted bidirectionally between a reader 18 ″ and its antenna 19 ″ and each of the supplemental antennas 52 and also bidirectionally between the supplemental antennas and those cases in the row above the slip sheet and those cases in the row below the slip sheet . paper sheet material having a basis weight of between about 40 and about 200 per 3000 ft 2 is commonly employed as slip sheet material . desirably , the slip sheet material contributes minimally to the cost of the completed slip sheet in that slip sheets commonly are not recycled as slip sheets . however , depending upon the durability of the slip sheet material , if desired , the antennae - bearing slip sheets may be recycled . fixation of the antennas 52 to the top surface 54 of the slip sheet 56 may be by any conventional means for affixing antennas to planar materials . in addition to glue - type affixation of the antennas to the slip sheet , the antennae may be printed on or embossed into the slip sheet , embedded in the slip sheet , plasticized or other wise fixed in their spaced apart locations over the top surface of the slip sheet . through choice of the size and geometry of the multiple antennas 52 , the present inventors may selectively provide suitable antennas for any of a large variety of shapes and sizes of cases , cartons , etc . on the pallet . whereas the slip sheet depicted in fig3 includes supplemental antennas 52 on only the top surface of the slip sheet , it will be understood that supplemental antennas may be affixed also to the bottom surface 70 of the slip sheet . in such event , the material of the slip sheet will not be transparent to rf signals . in one embodiment of an antenna - bearing slip sheet 56 of the present invention , as shown in fig3 and 5 , the slip sheet is wider in at least one dimension than the anticipated stack of cases on the pallet so that when the slip sheet is disposed between adjacent rows of cases on the pallet , short portions 75 and 77 of the opposite ends 72 and 74 , respectively , of the slip sheet project beyond the outer ones of the cases on the pallet . in this embodiment , the inventor provides a perforations or score ( fold ) line 76 and 78 inwardly of at least two opposite ones of those side edges 72 which project laterally beyond the stacked cases on the pallet . this perforation or score line is disposed inwardly from respective ones of these projecting side edges by a distance substantially equal to the length of each overhang . thereby , each such side edge may be folded upwardly or downwardly to provide more ready accessibility of rf signals from the reader to the supplemental antennas disposed on the slip sheet interiorly of the palletized cases . any of the four opposite side edges of the slip sheet may be provided with perforations or score lines , as desired , thereby eliminating directionality of application of the slip sheet between the rows of the cases . that is , one can choose which ones of the opposite sides of the slip sheet are up or down folded to accommodate the known orientation of the pallet at the time it is being exposed to the rf signals , such as when the pallet is passing through a fixed reader apparatus . in a further embodiment of the present invention , as depicted in fig6 , the slip sheet may comprise a lamination 80 which includes a outer top layer 82 , an outer bottom layer 84 and either a plurality of supplemental antennas 86 disposed between such outer top and bottom layers , or a plurality of antennas disposed on a third inner layer . as noted above , each of the outer layers , and any intermediate layer , is transparent to rf signals , thereby permitting rf transmission to take place between the supplemental antennas disposed internally of the laminate and a reader and tags associated with the cases on the pallet . one embodiment includes lamination onto a corrugated paperboard substrate . conventional laminating apparatus and processes may be employed in the formation of a laminate as depicted in fig6 . in accordance with one aspect of the present invention , the ability to create electromagnetic pathways through a palletized grouping of rfid - tagged products opens up the opportunity of eliminating those current limitations of the 915 mhz frequency togs which are associated with the physics of systems currently in use . further , as desired or used , the slip sheet may be seamed or perforated to provide visibility of the electromagnetic pathway to the readers . whereas the present invention has been described employing specific examples , it is intended that the invention be limited only as set forth in the claims appended hereto . moreover , whereas the permanent slip sheets may not provide for identification of 100 % of the rfid tags in an aggregation of tagged products , the present invention has repeatedly demonstrated identification of ninety - plus percent of palletized tagged products which have liquid or metal materials associated therewith .