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WO1997016864A1 - Blindage d'antenne ameliore et ensemble antenne - Google Patents

Blindage d'antenne ameliore et ensemble antenne Download PDF

Info

Publication number
WO1997016864A1
WO1997016864A1 PCT/US1996/017220 US9617220W WO9716864A1 WO 1997016864 A1 WO1997016864 A1 WO 1997016864A1 US 9617220 W US9617220 W US 9617220W WO 9716864 A1 WO9716864 A1 WO 9716864A1
Authority
WO
WIPO (PCT)
Prior art keywords
shield
molded
accordance
antenna
support
Prior art date
Application number
PCT/US1996/017220
Other languages
English (en)
Inventor
William R. Accolla
Markus B. Kopp
Scott Tribbey
Dennis Jordan
Original Assignee
Sensormatic Electronics Corporation
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Sensormatic Electronics Corporation filed Critical Sensormatic Electronics Corporation
Priority to AU74789/96A priority Critical patent/AU7478996A/en
Publication of WO1997016864A1 publication Critical patent/WO1997016864A1/fr

Links

Classifications

    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01Q—ANTENNAS, i.e. RADIO AERIALS
    • H01Q1/00—Details of, or arrangements associated with, antennas
    • H01Q1/52—Means for reducing coupling between antennas; Means for reducing coupling between an antenna and another structure
    • H01Q1/526—Electromagnetic shields
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01Q—ANTENNAS, i.e. RADIO AERIALS
    • H01Q7/00—Loop antennas with a substantially uniform current distribution around the loop and having a directional radiation pattern in a plane perpendicular to the plane of the loop
    • H01Q7/04—Screened antennas

Definitions

  • This invention relates to an electronic article surveillance (“EAS”) system and, in particular, to an antenna shield and an antenna assembly for use in such a system.
  • EAS electronic article surveillance
  • transmitter antennas are used to transmit electromagnetic fields into an interrogation zone.
  • the tag causes a perturbation in the transmitted field which can be sensed by the receiver antennas of the system.
  • the sensed EAS tag signals are coupled by the receiver antennas to a central processing unit which detects the signals and causes an alarm signal to be generated.
  • shields In an EAS system of this type, it is important that the field transmitted by the transmitter antennas be confined to the interrogation zone. It is also important that the receiver antennas be isolated from electrical noise and from any EAS tag signals and other unwanted signals generated outside the interrogation zone.
  • various forms of antenna shields have been used for shielding the transmitter and receiver antennas.
  • One form of shield comprises a laminate of flat sheets of pre-selected magnetic and conductive materials which is situated adjacent the transmitter and receiver antennas.
  • Another form of shield also comprises a laminate of sheets of material, but with the ends of the sheets bent or angled forward to provide enhanced retention of the field within the interrogation zone.
  • conductive strips are also placed adjacent the bends to prevent field leakage through the bend areas. A description of this type of shield can be found in U.S. Patent Number 5,130,697.
  • an object of the present invention to provide an antenna shield which is of simple configuration.
  • an antenna shield comprising a continuous sheet of metallic material having a central section and a lip section extending from and about the periphery of the central section.
  • the lip section extends arcuately from the periphery of the central section and then in a direction transverse thereto so that the shield takes the form of a concave member or shallow bowl.
  • the metallic material is pre-annealed cold rolled steel and the central section is of rectangular configuration.
  • the shield is formed from a flat sheet of material which is cold worked to form the central section and lip section. Cold working of the sheet material is kept at a level which both maintains the magnetic shielding properties of the material and achieves relative smoothness of the material without significant kinks, folds or wrinkles in the corner areas of the lip section.
  • an antenna assembly in which a molded shield support supports the antenna shield in nested relationship.
  • a molded antenna support nests with the nested shield support and shield.
  • a surface of the molded antenna support includes details for positioning the transmitter and receiver antennas in preselected relationship with each other and the antenna shield.
  • the surface details in the molded antenna support are in the form of recessed areas.
  • FIG. 1 shows an antenna pedestal including an antenna assembly and antenna shield in accordance with the principles of the present invention
  • FIG 2. shows an exploded view of the antenna shield support and antenna shield of the antenna assembly of FIG. l;
  • FIG. 3 shows the antenna support surface of the antenna support of the antenna assembly of FIG. 1;
  • FIG. 4 shows an assembly for forming the antenna shield of FIG. 2.
  • FIG. 1 illustrates an exploded view of an antenna pedestal 1 incorporating an antenna assembly 2 having an antenna shield 3 in accordance with the principles of the present invention.
  • the antenna pedestal 1 includes front and back plates 4 and 5 having vertical edges 4A and 5A, respectively, which are formed as mating hooks.
  • the plates 4 and 5 enclose the antenna assembly 2 and give an aesthetically pleasing finished look to the pedestal structure.
  • the antenna assembly 2 itself includes a shield support 6, the shield 3, an antenna support 7, transmitter antennas 8A and 8B and receiver antennas 9A - 9D.
  • the shield support 6 is in the form of a molded plastic shallow bowl or concave member having a rectangular central region 6A and a flange or lip portion 6B which extends arcuately and then transversely from the central region.
  • the shield 3 is of thin, flexible, metallic construction and is nested within and adhesively bonded to the shield support 6.
  • the shield 3 has a central region 3A and a lip region 3B extending arcuately from the periphery of the central region and then transversely thereto to give the shield also a shallow bowl or concave shape.
  • the presence of the lip region 3B on the shield 3 helps to enhance the shielding effect of the shield by providing points of attraction for magnetic flux lines.
  • the shield 3 is formed from a sheet of standard pre-annealed metallic stock.
  • the sheet material might be cold rolled steel having a thickness of .006 inches and which has been pre-annealed to maintain the desired magnetic shielding properties.
  • the degree of cold working of the sheet is kept to a level which avoids substantial degradation in the magnetic shielding properties of the material, while realizing relative smoothness without significant kinking, folding or wrinkling, particularly in the corner areas of the resultant concave member. This facilitates nesting of the shield and avoids areas of bulging in the antenna assembly and completed pedestal.
  • the molded antenna support 7 has opposing first and second surfaces 7A and 7B and nests with the nested assembly of the shield 3 and shield support 6.
  • the surface 7B of the antenna support 7 includes molded in details for positioning the receiver antennas 9A - 9D and transmitter antennas 8A - 8B. These details are in the form of recessed areas 7C - 70. Additionally, they can be in the form of positioning ribs.
  • the antennas 9A - 9D and 8A - 8B are positioned via the above mentioned details against the surface 7B of the antenna support and are secured thereto by an adhesive such as an epoxy cement. With the antennas secured to the support 7 and the latter support nested with the shield 3 and the shield support 6, upper shoulders 11 and 12 and side pieces 13 and 14 capture the antenna support 7 and the shield support 6 and hold them together to form the resultant antenna assembly 2.
  • the lower part of the shield support 6 is provided with a bay area 6C for housing electronics for the pedestal.
  • This bay area is closed off by plates 15-19 which are suitably secured thereto and by the front and back plates 4 and 5.
  • the upper part of the shield support includes an indentation 6D for receiving a lamp assembly 21 which can be seen through a viewing glass 5B in the upper part of the front plate 5.
  • An indentation 4B in the upper part of the back plate 4 allows access to the lamp assembly 16.
  • the overall antenna pedestal l comprised of the antenna assembly 2 and back and front plates 4 and 5 exhibits similar characteristics, i.e., is thin, strong, rigid and flat. This, in turn, makes the pedestal especially attractive for use in aisle locations in stores where a minimum of disturbance to the aisle traffic is desired.
  • the shield 3 is formed from a sheet material having the desired magnetic shielding properties and which is formed into the desired shallow bowl or concave shape from a standard stock of pre-annealed cold- rolled sheet material. This is accomplished as shown in FIG. 4, by cold-working the sheet material by using a press 31 to force the material into a die 32 with the desired bowl or concave shape.
  • tension members 33 are placed about the periphery of the sheet as it is being pressed.
  • a typical sheet material for forming the shield 3 might be a .006 inch thick sheet of pre-annealed cold rolled steel.
  • the tension members 33 are normally set so there is no more than a few (less than about 4) kinks, wrinkles or folds in the corner areas of the resultant concave member.
  • Typical dimensions for the shield 3 might be a length and width for the central region of 4 feet and 2 feet.
  • a typical lip section may comprise a 90° arc of radius 1.5 inches.
  • the shield 3 can have a central region which is other than rectangular such as, for example, circular. Also, the sheet material used to form the shield 3 need not be pre-annealed.

Landscapes

  • Physics & Mathematics (AREA)
  • Electromagnetism (AREA)
  • Shielding Devices Or Components To Electric Or Magnetic Fields (AREA)

Abstract

L'invention porte sur un blindage d'antenne (3) constitué d'une seule feuille continue d'un matériau de forme concave ayant une partie centrale (3A) et une partie formant un rebord (3B) se déployant en arc et transversalement par rapport à la partie centrale (3A). Ce blindage d'antenne (3) est emboîté dans un support (6) de blindage en plastique moulé de forme concave tandis qu'un support (7) d'antenne en plastique moulé, qui s'emboîte dans le blindage (3) et son support (6), est pourvu d'une face (7B) présentant des éléments (7C-7O) permettant de positionner des antennes émettrices et réceptrices (8A, 8B, 8C, 8D et 9A, 9B, 9C, 9D).
PCT/US1996/017220 1995-11-02 1996-10-29 Blindage d'antenne ameliore et ensemble antenne WO1997016864A1 (fr)

Priority Applications (1)

Application Number Priority Date Filing Date Title
AU74789/96A AU7478996A (en) 1995-11-02 1996-10-29 Improved antenna shield and antenna assembly

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
US55676795A 1995-11-02 1995-11-02
US08/556,767 1995-11-02

Publications (1)

Publication Number Publication Date
WO1997016864A1 true WO1997016864A1 (fr) 1997-05-09

Family

ID=24222782

Family Applications (1)

Application Number Title Priority Date Filing Date
PCT/US1996/017220 WO1997016864A1 (fr) 1995-11-02 1996-10-29 Blindage d'antenne ameliore et ensemble antenne

Country Status (2)

Country Link
AU (1) AU7478996A (fr)
WO (1) WO1997016864A1 (fr)

Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR2809279A1 (fr) * 2000-05-18 2001-11-23 Lionel Prat Habillage pour une antenne d'appareil de detection d'objets, et appareil de detection comportant une antenne equipee d'un tel habillage
US6819013B2 (en) * 2000-11-20 2004-11-16 Draeger Medical Systems, Inc. Electrically isolated power and signal coupler system for a patient connected device
AU778794B2 (en) * 2000-11-10 2004-12-23 Collaros Eas Technical Services Pty Ltd Antenna panel
WO2019113489A1 (fr) * 2017-12-08 2019-06-13 Sensormatic Electronics, LLC Socle blindé avec capacité de transparence

Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4859991A (en) * 1987-08-28 1989-08-22 Sensormatic Electronics Corporation Electronic article surveillance system employing time domain and/or frequency domain analysis and computerized operation
US5130697A (en) * 1990-10-30 1992-07-14 Sensormatic Electronics Corporation Method and apparatus for shaping a magnetic field
US5345222A (en) * 1990-02-28 1994-09-06 Esselte Meto International Produktions Gmbh Detection apparatus for security systems

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4859991A (en) * 1987-08-28 1989-08-22 Sensormatic Electronics Corporation Electronic article surveillance system employing time domain and/or frequency domain analysis and computerized operation
US5345222A (en) * 1990-02-28 1994-09-06 Esselte Meto International Produktions Gmbh Detection apparatus for security systems
US5130697A (en) * 1990-10-30 1992-07-14 Sensormatic Electronics Corporation Method and apparatus for shaping a magnetic field

Cited By (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR2809279A1 (fr) * 2000-05-18 2001-11-23 Lionel Prat Habillage pour une antenne d'appareil de detection d'objets, et appareil de detection comportant une antenne equipee d'un tel habillage
AU778794B2 (en) * 2000-11-10 2004-12-23 Collaros Eas Technical Services Pty Ltd Antenna panel
US6819013B2 (en) * 2000-11-20 2004-11-16 Draeger Medical Systems, Inc. Electrically isolated power and signal coupler system for a patient connected device
WO2019113489A1 (fr) * 2017-12-08 2019-06-13 Sensormatic Electronics, LLC Socle blindé avec capacité de transparence
US10580273B2 (en) 2017-12-08 2020-03-03 Sensormatic Electronics, LLC Shielded pedestal with see-thru capability

Also Published As

Publication number Publication date
AU7478996A (en) 1997-05-22

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