CN1322391A - Multiple loop antenna - Google Patents
Multiple loop antenna Download PDFInfo
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- CN1322391A CN1322391A CN98814304A CN98814304A CN1322391A CN 1322391 A CN1322391 A CN 1322391A CN 98814304 A CN98814304 A CN 98814304A CN 98814304 A CN98814304 A CN 98814304A CN 1322391 A CN1322391 A CN 1322391A
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- antenna
- loop element
- loop
- transmitting antenna
- reception antenna
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- 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
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- G—PHYSICS
- G08—SIGNALLING
- G08B—SIGNALLING OR CALLING SYSTEMS; ORDER TELEGRAPHS; ALARM SYSTEMS
- G08B13/00—Burglar, theft or intruder alarms
- G08B13/22—Electrical actuation
- G08B13/24—Electrical actuation by interference with electromagnetic field distribution
- G08B13/2402—Electronic Article Surveillance [EAS], i.e. systems using tags for detecting removal of a tagged item from a secure area, e.g. tags for detecting shoplifting
- G08B13/2465—Aspects related to the EAS system, e.g. system components other than tags
- G08B13/2468—Antenna in system and the related signal processing
- G08B13/2474—Antenna or antenna activator geometry, arrangement or layout
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- Engineering & Computer Science (AREA)
- Physics & Mathematics (AREA)
- Signal Processing (AREA)
- Automation & Control Theory (AREA)
- Computer Security & Cryptography (AREA)
- Electromagnetism (AREA)
- General Physics & Mathematics (AREA)
- Variable-Direction Aerials And Aerial Arrays (AREA)
- Near-Field Transmission Systems (AREA)
- Burglar Alarm Systems (AREA)
- Aerials With Secondary Devices (AREA)
- Support Of Aerials (AREA)
Abstract
A multiple loop antenna is provided which may be connected to either a transmit circuit, a receive circuit, or a transmit/receive circuit. When powdered by a transmit circuit, the antenna generates radio frequency magnetic fields in an area or zone proximate to the antenna, but which are substantially canceled at a distance approximately one wavelength and more from the antenna, thereby defining a surveillance zone proximate to the antenna. The loop antenna includes a first, upper loop and a second, lower loop. The upper and lower loops lie in separate, spaced, parallel planes and are preferable disposed at a fixed angle with respect to the surveillance zone.
Description
The present invention relates to radio-frequency antenna, more particularly, relate to the loop antenna that is created in from the general field of offsetting of distance of a wavelength of antenna or a plurality of wavelength.
In the electronic system of some known type, knownly provide one or more loop antennas, wherein an antenna and near it coupling of environment higher, but wherein the structure of antenna is such, thereby makes the coupling minimum between antenna and its distant place environment (promptly from the about wavelength of antenna or a plurality of wavelength).This antenna generally is used for near-field communication or detection applications, and wherein term " near field " is meant in the scope of antenna half wavelength.The example of this purposes comprises with the short-distance wireless regional area communication network of communicating by letter, be used for computer of the medicine equipment of inserting and comprises the rfid system of eas (EAS) system.Generally, to the coupling of these loop antennas mainly through magnetic induction.
For example, radio frequency EAS system generally includes a transmit antennas and a reception antenna of setting up a monitor area jointly and is attached to label on the protected article.Transmitting antenna produces the variable frequency electromagnetic field in one second scheduled frequency range.Each comprises a resonant circuit with the predetermined resonant frequency that generally equals first frequency label.When one of label is present in the monitor area, induce a voltage in the resonant circuit of field in label by the transmitting antenna generation, this voltage makes resonant circuit produce an electromagnetic field, causes the interference in the monitor area internal field.The reception antenna detection of electromagnetic fields is disturbed, and produces the indication signal that label exists in monitor area (and thereby, indication is attached to the existence of the protected article on the label).
The structure of these antenna should satisfy two purposes: (1) makes the distance of crossing between emission and reception antenna for the coupling of label wide as much as possible; (2) make minimum for the coupling in far field.These purposes are contradiction.The prior art antenna, as by Lichtblau in U.S. Patent No. 4,243,980,4,269,990 and 4, those that describe in 866,455-, generally comprise two or more coplane loops here by with reference to comprising, thereby in conjunction with the size of each loop, the current values in loop and the sense of current produce when general field of offsetting when measuring away from a some place of antenna.In other words, from the field of each establishment of loop when when summation clear to be approximately zero.The counteracting of this far field is impossible when only using a loop.In 8 font loop antennas, loop generally is a rectangle, arrange with a kind of coplanar arrangement, and on the position, be offset, thus the approximate side of at least one side of each loop to another loop.In other words, common side is tightly adjacent each other.
The invention provides a kind of antenna that increases coupling in the far field coupling performance that reduces greatly and the wide zone between a transmit antennas and reception antenna that has.Usually, this antenna (perhaps emission or receive) comprises that first and second loops that are equal to size and dimension generally speaking, its intermediate ring road are arranged in the fixed position on the opposite side of an axis of centres, and this axle extends between loop.And loop is positioned in separation, that separate, the parallel plane.Loop is connected to each other, and is connected on a radiating circuit or the receiving circuit by a crossing conductor.Best, the length of crossing conductor from first loop to (emission or reception) circuit equals the length of crossing conductor from second loop to this circuit.Electric current in loop flows in the opposite direction, and the field that produces basic neutralisation thus.The invention provides a kind of for the external emission signal height sensitivity in the close zone of antenna and for highly insensitive antenna that transmits at a distance.
Speak briefly, the present invention includes a kind of multiple loop antenna, this antenna comprises:
One first loop element;
One second loop element, wherein first and second loop element have the basic size that equates, and are arranged in separation, that separate, substantially parallel plane; And
A crossing member comprises an electric conductor that is used for being electrically connected the one the second loop element.
The present invention also is intended to a kind of electronic article monitoring system, and this system comprises:
A radiating circuit element;
One transmit antennas, electrical couplings is to the radiating circuit element that is used for generating an electromagnetic field, transmitting antenna comprises first and second loop element of basic equivalent size, loop element is in general that separate, plane that separate, parallel, and a crossing conductor the first and second loop element electrical couplings together;
A reception antenna, separate with transmitting antenna, reception antenna comprises first and second loop element of basic equivalent size, loop element is in general that separate, plane that separate, parallel, and a crossing conductor the first and second loop element electrical couplings together, reception antenna measure-alike with transmitting antenna basically wherein, and one of them monitor area is limited between transmitting antenna and the reception antenna; And
A receiving circuit element, electrical couplings to reception antenna so that detect a resonant in the monitor area under a preset frequency resonance and produce the alarm signal of indication existence of protected article monitor area from it.
In a most preferred embodiment, the present invention is a kind of electronic article monitoring system, and this system comprises:
A radiating circuit element;
One transmit antennas, electrical couplings is to the radiating circuit element that is used for generating an electromagnetic field, transmitting antenna comprises first and second loop element of basic equivalent size, loop element is in general that separate, plane that separate, parallel, and a crossing conductor the first and second loop element electrical couplings together;
A reception antenna, separate with transmitting antenna, reception antenna comprises first and second loop element of basic equivalent size, loop element is separated general, separate, in the parallel plane, and a crossing conductor the first and second loop element electrical couplings together, reception antenna measure-alike with transmitting antenna basically wherein, wherein a trunnion axis that generally passes the geometric center extension of transmitting antenna separates first and second loop element of transmitting antenna and each root of reception antenna, thereby first and second loop element of every respective antenna are positioned at the opposite side of trunnion axis, and one of them monitor area is limited between transmitting antenna and the reception antenna, monitor area comprises a passage that extends between transmitting antenna and reception antenna, wherein each of the loop element of transmitting antenna and reception antenna is fixed with a predetermined angular with respect to passage; And
A receiving circuit element, electrical couplings to reception antenna so that detect a resonant in the monitor area under a preset frequency resonance and produce the alarm signal of indication existence of protected article monitor area from it.
When read in conjunction with the accompanying drawings, the following detailed description of an above general introduction and a most preferred embodiment of the present invention will be understood better.For purpose of the present invention is described, expression has a current illustrated embodiments in the drawings.Yet, should be appreciated that, the invention is not restricted to the concrete utensil of arranging and representing.In the accompanying drawings:
Fig. 1 is the schematic diagram that antenna is offset in the prior art far field;
Fig. 2 is the schematic diagram of offsetting antenna according to a kind of far field of the present invention;
Fig. 3 offsets the schematic diagram of antenna and the phantom of one second antenna in a housing according to a kind of far field that is used in first antenna that has an expression in a housing of the present invention;
Fig. 4 is the cutaway view of the 4-4 along the line of system of Fig. 3; And
Fig. 5 is the stereogram of a kind of antenna of the present invention in a decorative shell.
Some term is only used in the following description for convenience, rather than restrictive.Speech " top ", " bottom ", " bottom " reach " top " indication it are carried out direction among the figure of reference.Term comprises the speech of speech, its derivative and the similar introducing of above special description.
The present invention is intended to a kind of antenna that can mainly transmit and receive electromagnetic energy through magnetic induction, and wherein the size of antenna is basically less than the wavelength of emission or the electromagnetic energy that receives.Antenna of the present invention be applicable to well wherein near antenna (promptly in scope) less than half wavelength from or to the main system that occurs of energy coupling of antenna.An a kind of like this example of system is wherein to use antenna to set up the EAS system of a monitor area.Certainly, a kind of like this antenna has other obvious purposes for those technical staff that are familiar with prior art, and this EAS system only is an illustrative example of antenna use.
In a kind of EAS system, antenna is used for being actuated at resonant circuit in the safety label, and detects this label then.The safety label (not shown) of using with the present invention generally has the type of knowing in the prior art of EAS system.This label is suitable for seeking safety or packing of this article that monitor is fixed by article or product or to it, otherwise is loaded with by it.Label can be fixed on article or its packing at retail shop or other such facility places, and perhaps manufacturer or the whole seller by article fixes or be included in article or its packing.Safety label comprises the element of setting up a resonant circuit, and this resonant circuit is when being exposed under the predetermined detection resonance frequency or resonance during near the electromagnetic energy it.Contact EAS system, particularly radio frequency or RF type EAS system, this label of use is known in prior art, and therefore, the complete description of the structure of this label and operation is optional for the understanding of the present invention.Be subjected to monitor area or regional interior resonance or response just enough as long as say this label when being positioned at one, this is subjected to the general import or export near the facility such as retail shop of monitor area.Resonant is detected by safety system then, and this safety system activates an alarm so that notify office worker's label in being subjected to monitor area.
Now at length with reference to accompanying drawing, wherein similarly label is indicated similar elements from start to finish, expression has the prior art far field of a kind of EAS system that is used for producing and/or be coupled on the electromagnetic field to offset the schematic diagram of antenna 10 in Fig. 1, this antenna is disclosed in detail authorizes ChechpointSystems, Inc.of Thorofare, the U.S. Patent No. 4,243 of New Jersey, in 980, its disclosure is included in here by reference.Usually, antenna 10 comprises one first, top loop 12 and one second, lower loop 14, upper and lower loop 12,14 coplanes.Upper and lower loop 12,14 generally has equal size, and is generally tetragonal shape, thereby the whole shape of combination upper and lower loop 12,14 generally is a rectangle.
In an EAS system, the reception antenna (not shown) of and transmitting antenna 10 same sizes and configuration general one, near antenna 10 place in case between it monitor area of establishment.According to the present invention, each includes first and second loop element of general same size and shape to transmit and receive antenna.First and second loop element that are connected with a crossing conductor are positioned in that separate, that separate, the parallel plane each other.In the time of on being connected to a transmitter, have the far field coupling performance that reduces greatly and the coupling of increase in the wide zone of antenna between a transmit antennas and reception antenna.Thereby antenna of the present invention is applicable to the EAS purposes well.
Referring now to Fig. 2, expression is according to a kind of block schematic diagram of improving loop antenna 30 of the present invention.Fig. 2 comprises a trunnion axis 32 and a vertical axis 34, and the every general geometric center of crossing antenna 30 of axle is extended, so that more clearly describe and describe the shape and size of antenna 30.Antenna 30 consists essentially of first or the top loop circuit component 36 and second or the lower loop element 38 that mainly is positioned at trunnion axis 32 belows that mainly are positioned at trunnion axis 32 tops.As shown in Figure 2 and as desired, upper and lower loop element 36,38 has the basic size and dimension that equates, and is arranged in separation, that separate, substantially parallel plane.In this most preferred embodiment, first and second loop element separate each other about 18 to 22 inches.Certainly, those skilled in the art will be understood that, can use the distance that is greater than or less than the 18-22 inch between top and lower loop element 36,38 for the present invention.
Each preferably includes the conductor or the lead of a circle or any suitable type of multiturn top loop circuit component 36 and lower loop element 38, and as the conductor of different specification size, these conductors are known for those skilled in the art.Preferably upper and lower loop element 36,38 is built or is formed by solid conductor.Yet, will understand, if wish, can use other transport element, as many conductors, and do not depart from the scope of the present invention.For example, can wish to use the mechanical function structural detail to form first and second loop element 36,38.Perhaps, can use conduction decoration element (not shown).
Although respectively loop element 36,38 is called " top " and " bottom " loop element, but it is obvious for those skilled in the art, descriptive term " top " is relative with " bottom ", and loop element 36,38 relative to each other can be with other azimuthal orientations.
Top loop circuit component 36 is generally rectangular shape, and this rectangle has second limit 42 that first limit 40 that is basically parallel to vertical axis 34, one be basically parallel to trunnion axis 32, one and is parallel to first limit 40 and the 3rd limit 44 of extending from second limit 42, and the 4th limit 46 that comprises two separating part 46a, 46b.
Similarly, lower loop element 38 generally also is a rectangular shape, and this rectangle has second limit 54 that first limit 52 that is basically parallel to vertical axis 34, one be basically parallel to trunnion axis 32, one and is basically parallel to first limit 52 and the 3rd limit 56 of extending from second limit 54, and the 4th limit 58 that comprises two separating part 58a, 58b.
Crossing member that comprises pair of conductors 48,50 extends from appropriate section 46a, the 46b on the 4th limit 46 of top loop circuit component 36, and top loop circuit component 36 is connected with part 58a, the 58b on the 4th limit 58 of lower loop element 38 respectively.Crossing member conductor 48,50 preferably includes a pair of lead that closely separates or conductor, as a twin conductor or a parallel shielded type cable, and has a predetermined length that connects upper and lower loop element 36,38.Best, crossing conductor 48,50 is below a position near trunnion axis 32 extends to trunnion axis 32.Because upper and lower loop element 36,38 is arranged in separation, that separate, parallel plane, so crossing conductor also horizontal-extending between top and lower loop element 36,38 except that vertical extent.Although preferably connect upper and lower loop element 36,38 as shown, be appreciated that other sides by the respective loops element 36,38 that is connected to each other also can connect upper and lower loop 36,38.For example, the 4th limit 46 of top loop circuit component 36 can be connected on second limit 54 of lower loop element 38, and perhaps the 3rd limit 44 of first loop element 36 can be connected on first limit 52 of second loop element 38.
Although each of upper and lower loop element 36,38 is expressed as rectangle, does not require that the upper and lower loop is made up of rectangle, and only require upper and lower loop element 36,38 to have similar size and geometry.For example, top and lower loop 36,38 can comprise other geometries, as circular, oval or triangle.
Drive on antenna 30 energy electrical couplings to an electric device or the circuit and by it, this electric device or circuit can be at the transmitter circuitry under the transmit antennas situation, at the receiver circuit under the reception antenna situation or at an emittor/receiver circuit that is designed under the two-way communication antenna situation.Under the situation of transmitting antenna, circuit element can comprise the current source of an electrical couplings to the antenna, so as electric current supply to the antenna that is enough to generate an electromagnetic field.For example, circuit can be one and comprises a signal oscillator (not shown) and the amplifier/FL-network (not shown) that can drive the type of the load impedance that is presented by antenna.In Fig. 2, a transmitter 60 is connected on the crossing conductor 48,50 of antenna 30.
Best, the size of antenna 30 is basically less than a wavelength of the operation of antenna 30, thus the antenna 30 main magnetic fields that produce.For example, the first and the 3rd limit 40,44 of first and second loop element 36,38 and 52,56 length can be respectively about 30-40 inches, and second limit 42,54 of first and second loop element 36,38 can be respectively about 1-15 inch.Yet those skilled in the art will understand, and the size of loop element 36,38 can change with the hope size of purposes and monitor area.In a most preferred embodiment of the present invention, lower loop element 38 is about 2.0 inches of sides on the ground, and each of upper and lower loop element 36,38 has about 32 inches length and about 5.6 inches width.Those skilled in the art will be further understood that, upper and lower loop element 36,38 even can be of different sizes, and by changing the far field counteracting that can realize hope at loop element 36,38 current value in each.
Such as will be appreciated, the frequency of antenna radiated electromagnetic field depends on the oscillation rate of transmitter 60 basically under it.Thereby, can be provided with and regulating frequency by suitably regulating transmitter 60 with well-known way.Best, antenna 30 is exercisable under radio frequency, and radio frequency is wished to comprise and is higher than 1, the frequency of 000Hz, and comprise and be higher than 5, and the frequency of 000Hz is better, and comprises and be higher than 10, and the frequency of 000Hz is better.Yet, should be appreciated that antenna 30 can be operated and not depart from the scope of the present invention under lower frequency.In this most preferred embodiment, label is preferably under the 8.2MHz or near resonance it, this frequency is a kind of shared frequency that is used by the electronic safety system from a plurality of manufacturers, although obvious for those skilled in the art, the frequency of EAS system can change according to local condition and rules.Thereby this characteristic frequency is not thought restriction of the present invention.
Perhaps, circuit can comprise that electrical couplings is used for receiving from the resonant circuit of a transmit antennas and/or a label (not shown) receiver circuit (not shown) of electromagnetic energy to the antenna 30, so that produce a near whether indication exists label antenna signal.This circuit element that is used for launching and/or receives generally is known.For example, in U.S. Patent No. 5,373, the sort circuit element has been described in 301.Do not need the more detailed description of circuit element in order to understand the present invention.
In this most preferred embodiment, a receiver circuit that uses with the present invention comprises a circuit for alarming as the well-known like that, so that resonant of generation indication is positioned at the alarm signal by the monitor area that transmits and receives the antenna definition.Yet, be not that ear-piercing beeping sound or alarm song are produced, but acceptor circuit comprises a storage device, as is used for storing a kind of predetermined customization alarm signal, as the well-known song tingtang or its part, non-volatile RAM or a programming ROM.Perhaps, can begin to know the record of sound.A kind of like this use that customizes audio signal, opposite with the beeping sound and the alarm of prior art, can be used for covering alarm function from client's receiver.
Best, the length of the crossing conductor 48,50 that (for example transmitter 60) are measured from top loop circuit component 36 to circuit element equals from lower loop element 38 to the circuit element length measured.Between top and lower loop element 36,38, transmitter 60 is coupled into equidistant basically, help to provide identical currents by same conductor section, these same conductor section comprise the intersection and the loop 36,38 of antenna 30, obtain thus from 30 1 distances of antenna the field accurate counteracting.Thereby make the far field coupling minimum.In the exchange mode, in the time of on being connected to a receiver, make 30 pairs on antenna in sensitivity minimum from the signal of 30 1 distances of antenna.
Referring now to Fig. 3, an EAS system 70 of expression comprises the transmitting antenna and the reception antenna that is contained in second decorating structure 74 that are contained in the decorating structure 72.Preferably decorating structure 72,74 is built by the non-conductive material such as polymeric material, and a kind of rigidity supporting structure that is used for holding the antenna loop element is provided.Each comprises respectively that preferably being used for holding first and second of upper and lower loop element 36,38 separates cylindrical shells 76,78 decorating structure 72,74.First cylindrical shell 76 also holds a printed circuit board (PCB) 80 electronic component relevant with it, these electronic components or comprise transmitter 60 or comprise receiver.In other words, top loop circuit component 36 is arranged in housing 76 tops or top, and PCB 80 is arranged in the bottom or the end half one of housing 76.Crossing conductor 48,50 extends between cylindrical shell 76,78, to connect upper and lower loop element 36,38 and circuit element.
Certainly, do not require that a separating husk body is used for upper and lower loop element 36,38, because such element can be contained in the single structure.Moreover one or more cross bar (not shown)s can be placed between the housing 76,78 to add support structure to housing.
Fig. 5 is the stereogram of a most preferred embodiment of the decoration cylindrical shell 76,78 that can use with the present invention.Such cylindrical shell can be simulated Greece's post, and can be used as Plant holdfast.Thereby the EAS system is attractive and unnoticed.
Typically, interval in the EAS system between transmitting antenna and reception antenna is according to concrete EAS system and wherein adopt the concrete purposes of this system, in from two to five feet scope.Above-mentioned antenna structure provides a monitor area bigger than prior art antenna.For example, the EAS system is usually located at the outlet/inlet place of retail shop, canonical system have the transmitting antenna of first side that is positioned at outlet/inlet and one be positioned at outlet/inlet second, the reception antenna of opposite side.Set up for fear of nonimportation/outlet, wish the antenna width of outlet/inlet at least that separates each other, general about six feet of this width.
Unfortunately, multiple prior art system requirements transmits and receives antenna and separates each other much smaller than six feet distance, and even, need concentrated the passing through of personnel perhaps to be used in the outlet/inlet place in a space narrower more than two antennas than outlet/inlet less than five feet.Yet because the good far field cancelling capabilities of antenna structure of the present invention, the transmitter that is connected on the antenna can be operated under very high power, and can not create the far-field emission of violating the FCC rule.
In addition and since the signal that produces by the label in the antenna monitor area on amplitude with to be used for the amplitude of signal of driven antenna proportional, so realize that having a net increase of of label signal is big, this provides the corresponding increase of system signal noise ratio.It is far away than current EAS system that this increase of signal to noise ratio allows a transmit antennas to be arranged to from a reception antenna.For example, transmit and receive the opposite side that antenna can be positioned at six feet shop imports of standard, this allows client more easily to pass in and out the shop.In other words, antenna structure of the present invention allows to transmit and receive antenna and separates greater than six feet, and still detects the label that passes through between it.Also can increase channel width by the opposite side that reception antenna is placed on transmitting antenna, limit two passages thus.
Certainly, as being understood by those skilled in the art, the size of resonant or mark also is a factor of determining the interval between emission and reception antenna.For example, using the EAS system of big label to allow to transmit and receive antenna places than the system that requires to detect less label a long way off.Yet,, transmit and receive antenna and can separate distance, and still can not only detect big label but also detect little label greater than six feet according to the present invention.
Fig. 4 is the cutaway view of 70 4-4 along the line of EAS system of Fig. 3.Passage or monitor area have an arrow 82, and the indication personnel advance to leave the direction in the shop of using EAS system 70.Best, transmitting antenna and reception antenna each upper and lower loop element 36,38 with respect to passage at a predetermined angle θ fix.Angle θ wishes less than 90 °, and be about 45 ° better.Notice that loop element 36,38 is fixed, and can not move or change the position, as the known prior art antenna in being installed in door or similar structures.
Although described specific embodiments of the invention, obviously, the present invention can change or revise, and still provides the far field of hope to offset and do not depart from the scope of the present invention and spirit.Moreover, although passed through with reference to the EAS system description antenna of the present invention here, will recognize that this reference for the EAS system only provides for the purpose of illustration, rather than restrictive.Antenna of the present invention is applicable to the purposes of multiple other types well, and more particularly, has wherein the electromagnetic energy by aerial radiation is used for finishing purposes in any zone of communication or discriminant function.For example, antenna of the present invention can be in conjunction with a transducer (it by by antenna electromagnetic energy emitted power supply) with being difficult to therein to power or otherwise in the environment of lead on being connected to transducer and sensor communication.In this environment, antenna can be used for remote power feeding or receive information from transducer.For example, antenna of the present invention can use in conjunction with a transducer of measuring patient's blood glucose value, wherein in the tissue of the subcutaneous implant patient of blood glucose value transducer.As understanding, wish that especially patient skin does not penetrate with the lead that is connected on the transducer.Also special hope is eliminated battery from transducer.With regard to the present invention, might use the electromagnetic energy that produces by antenna to power to be positioned at the transducer under the patient skin, and use antenna to receive electromagnetic energy simultaneously by sensor emission, wherein relevant with patient's blood glucose value by the electromagnetic energy of sensor emission.Another kind of purposes relates to one distinguishes its owner so that the passive transducer of access control is communicated by letter.Other useful purposes of the present invention also are obvious for those skilled in the art.
Those skilled in the art will further recognize, can change for the above embodiment of the present invention, and not break away from inventive concepts of the present invention.Therefore be appreciated that to the invention is not restricted to disclosed specific embodiment, and be intended to be included in all modifications and change by in the scope and spirit of the present invention of claims definition.
Claims (25)
1. multiple loop antenna comprises:
One first loop element;
One second loop element, wherein first and second loop element have the basic size that equates, and are arranged in separation, that separate, substantially parallel plane; And
A crossing member comprises an electric conductor that is used for being electrically connected first and second loop element.
2. antenna according to claim 1, wherein a trunnion axis that generally is passed in the central point extension between first and second loop element separates first and second loop element, thus first and second loop element are positioned at the opposite side of trunnion axis.
3. antenna according to claim 2, wherein a vertical axis that generally is passed in the central point extension between first and second loop element separates first and second loop element, thus first and second loop element are positioned at the opposite side of vertical axis.
4. antenna according to claim 1, wherein first and second loop element separate each other about 18 to 22 inches.
5. antenna according to claim 1 further comprises a circuit element that is connected on first and second loop element.
6. antenna according to claim 5, wherein crossing member is connected to first and second loop element on the circuit element.
7. antenna according to claim 6, wherein the length that first loop element is connected to the crossing member on the circuit element generally equals second loop element is connected to the length of the crossing member on the circuit element.
8. antenna according to claim 7, wherein circuit element comprises a transmitter.
9. antenna according to claim 8 is wherein flowed on first direction in first loop element by the electric current that transmitter produces, and flows on the second direction opposite with first direction in second loop element.
10. antenna according to claim 9 is wherein generally offset in the distance from a wavelength of antenna or a plurality of wavelength by the field that the electric current of first and second loop element of flowing through produces.
11. antenna according to claim 5, wherein circuit element comprises a receiver.
12. antenna according to claim 1, wherein the size of antenna is basically less than an operative wavelength of antenna, thereby antenna mainly produces magnetic field.
13. antenna according to claim 1 further comprises a kind of rigidity supporting structure that is used for holding first and second loop element.
14. antenna according to claim 13, wherein each of first and second loop element is contained in the supporting construction of a separation.
15. an electronic article monitoring system comprises:
A radiating circuit element;
One transmit antennas, electrical couplings is to the radiating circuit element that is used for generating an electromagnetic field, transmitting antenna comprises first and second loop element of basic equivalent size, loop element is in general that separate, plane that separate, parallel, and a crossing conductor the first and second loop element electrical couplings together;
A reception antenna, separate with transmitting antenna, reception antenna comprises first and second loop element of basic equivalent size, loop element is in general that separate, plane that separate, parallel, and a crossing conductor the first and second loop element electrical couplings together, reception antenna measure-alike with transmitting antenna basically wherein, and one of them monitor area is limited between transmitting antenna and the reception antenna; And
A receiving circuit element, electrical couplings to reception antenna so that detect a resonant in the monitor area under a preset frequency resonance and produce the alarm signal of indication existence of protected article monitor area from it.
16. electronic article monitoring system according to claim 15, wherein the trunnion axis that extends of the central point between first and second loop element that generally is passed in transmitting antenna separates first and second loop element of transmitting antenna, thereby first and second loop element of transmitting antenna are positioned at the opposite side of trunnion axis.
17. electronic article monitoring system according to claim 16, wherein trunnion axis also separates first and second loop element of reception antenna, thereby reception antenna first and second loop element also are positioned at the opposite side of trunnion axis.
18. electronic article monitoring system according to claim 15, wherein the vertical axis that extends of the central point between first and second loop element that generally is passed in transmitting antenna separates first and second loop element of transmitting antenna, thereby first and second loop element of transmitting antenna are positioned at its opposite side.
19. electronic article monitoring system according to claim 18, wherein vertical axis also separates first and second loop element of reception antenna, thereby reception antenna first and second loop element also are positioned at the opposite side of vertical axis.
20. electronic article monitoring system according to claim 15, wherein monitor area comprises a passage that extends between transmitting antenna and reception antenna, and wherein each of loop element of transmitting antenna and reception antenna is fixed with the predetermined angular with respect to passage.
21. electronic article monitoring system according to claim 20, wherein angle comprises about 45 °.
22. electronic article monitoring system according to claim 15, wherein acceptor circuit comprises a circuit for alarming that is used for producing alarm signal.
23. electronic article monitoring system according to claim 22, wherein alarm signal starts the audio signal of a customization.
24. electronic article monitoring system according to claim 15, wherein passage is greater than about six feet wide.
25. an electronic article monitoring system comprises:
A radiating circuit element;
One transmit antennas, electrical couplings is to the radiating circuit element that is used for generating an electromagnetic field, transmitting antenna comprises first and second loop element of basic equivalent size, loop element is in general that separate, plane that separate, parallel, and a crossing conductor the first and second loop element electrical couplings together;
A reception antenna, separate with transmitting antenna, reception antenna comprises first and second loop element of basic equivalent size, loop element is separated general, separate, in the parallel plane, and a crossing conductor the first and second loop element electrical couplings together, reception antenna measure-alike with transmitting antenna basically wherein, wherein a trunnion axis that generally passes the geometric center extension of transmitting antenna separates first and second loop element of transmitting antenna and each root of reception antenna, thereby first and second loop element of every respective antenna are positioned at the opposite side of trunnion axis, and one of them monitor area is limited between transmitting antenna and the reception antenna, monitor area comprises a passage that extends between transmitting antenna and reception antenna, wherein each of the loop element of transmitting antenna and reception antenna is fixed with a predetermined angular with respect to passage; And
A receiving circuit element, electrical couplings to reception antenna so that detect a resonant in the monitor area under a preset frequency resonance and produce the alarm signal of indication existence of protected article monitor area from it.
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| PCT/US1998/024182 WO2000030214A1 (en) | 1997-05-28 | 1998-11-12 | Multiple loop antenna |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN1322391A true CN1322391A (en) | 2001-11-14 |
| CN1123089C CN1123089C (en) | 2003-10-01 |
Family
ID=22268290
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN98814304A Expired - Fee Related CN1123089C (en) | 1998-11-12 | 1998-11-12 | Multiple loop antenna |
Country Status (6)
| Country | Link |
|---|---|
| EP (1) | EP1138098A4 (en) |
| JP (1) | JP2002530910A (en) |
| KR (1) | KR100605341B1 (en) |
| CN (1) | CN1123089C (en) |
| CA (1) | CA2350217C (en) |
| IL (1) | IL142387A (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN103634055A (en) * | 2003-02-27 | 2014-03-12 | 奎法特股份有限公司 | Communication system |
Families Citing this family (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP4772744B2 (en) * | 2007-05-17 | 2011-09-14 | 昭和飛行機工業株式会社 | Signal transmission coil communication device for non-contact power feeding device |
| KR101563428B1 (en) * | 2014-05-27 | 2015-10-26 | 재단법인대구경북과학기술원 | Near-field system |
| JP6369623B2 (en) * | 2015-02-24 | 2018-08-08 | 株式会社村田製作所 | Antenna device and RFID system |
Family Cites Families (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US3577136A (en) * | 1967-08-04 | 1971-05-04 | Security Systems Inc | Short-range signaling system |
| US4135184A (en) * | 1977-08-31 | 1979-01-16 | Knogo Corporation | Electronic theft detection system for monitoring wide passageways |
-
1998
- 1998-11-12 CA CA002350217A patent/CA2350217C/en not_active Expired - Fee Related
- 1998-11-12 EP EP98960188A patent/EP1138098A4/en not_active Withdrawn
- 1998-11-12 CN CN98814304A patent/CN1123089C/en not_active Expired - Fee Related
- 1998-11-12 IL IL14238798A patent/IL142387A/en not_active IP Right Cessation
- 1998-11-12 KR KR1020017004544A patent/KR100605341B1/en not_active IP Right Cessation
- 1998-11-12 JP JP2000583121A patent/JP2002530910A/en active Pending
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN103634055A (en) * | 2003-02-27 | 2014-03-12 | 奎法特股份有限公司 | Communication system |
Also Published As
| Publication number | Publication date |
|---|---|
| CA2350217A1 (en) | 2000-05-25 |
| JP2002530910A (en) | 2002-09-17 |
| IL142387A (en) | 2004-06-20 |
| CA2350217C (en) | 2006-04-04 |
| EP1138098A4 (en) | 2005-01-26 |
| CN1123089C (en) | 2003-10-01 |
| KR100605341B1 (en) | 2006-07-28 |
| KR20010106513A (en) | 2001-11-29 |
| EP1138098A1 (en) | 2001-10-04 |
| IL142387A0 (en) | 2002-03-10 |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| C06 | Publication | ||
| PB01 | Publication | ||
| C10 | Entry into substantive examination | ||
| SE01 | Entry into force of request for substantive examination | ||
| C14 | Grant of patent or utility model | ||
| GR01 | Patent grant | ||
| C17 | Cessation of patent right | ||
| CF01 | Termination of patent right due to non-payment of annual fee |
Granted publication date: 20031001 Termination date: 20101112 |