HK1113952B - Combination eas and rfid label or tag - Google Patents

Description

Combined electronic article surveillance and radio frequency identification tag or label

Cross Reference to Related Applications

U.S. provisional patent application No. 60/628,303 entitled "ComboEAS/RFID Label or Tag" filed 11/15 of 2004 as hereby incorporated by reference in its entirety for all purposes as if set forth at 35u.s.c. § 119.

Technical Field

The present disclosure relates to Electronic Article Surveillance (EAS) tags or labels that prevent or deter unauthorized removal of an article from a controlled area. More particularly, the present disclosure relates to an EAS tag or label in combination with a Radio Frequency Identification (RFID) tag or label or a new type of RFID tag or label that records item-specific data.

Background

Electronic Article Surveillance (EAS) systems are well known in the art for preventing or deterring unauthorized removal of articles from a controlled area. In a typical EAS system, EAS tags (labels or tags) are designed to interact with an electromagnetic field located at the exits of a controlled area, such as a retail store, and are attached to items to be protected. If the EAS tag is brought into an electromagnetic field or "interrogation zone," the presence of the tag is detected and appropriate action is taken, such as issuing an alarm. For items that are allowed to be removed, the EAS tag may be deactivated, removed, or bypassed around the electromagnetic field to prevent detection by the EAS system.

EAS systems typically employ reusable EAS tags or disposable EAS tags or labels to monitor articles to prevent shoplifting and unauthorized removal of the articles from the store. Reusable EAS tags are typically removed from an item before the customer exits the store. Disposable labels or tags are typically attached to or located within the package by an adhesive. These tags are typically associated with the articles and must be deactivated before the customer removes the articles from the store. The deactivation device may use a coil that is energized to generate a magnetic field of sufficient strength to deactivate the EAS tag. The deactivated tags no longer respond to the incident energy of the EAS system and thus do not trigger an alarm.

For situations where an item having an EAS tag is retrieved or returned to the control area, the EAS tag must be activated or reattached to again serve as an anti-theft function. Because it is desirable to apply EAS tags to the source tags of articles at the point of manufacture or distribution, it is generally desirable that the EAS tags be deactivatable or activatable, rather than being removed from the articles. In addition, other problems may arise with having items bypass the interrogation zone because the EAS tags remain active and may interact with EAS systems in other control zones to inadvertently activate those EAS systems.

Radio Frequency Identification (RFID) systems are also well known in the art and may be used in many applications such as managing inventory, electronic access control, security systems, and automatic identification of cars on toll roads. RFID systems typically include an RFID reader and an RFID device. The RFID reader may transmit a radio frequency carrier signal to the RFID device. The RFID device may respond to the carrier signal with a data signal encoded with information stored by the RFID device.

The market need to combine EAS and RFID functions in a retail environment is rapidly emerging. Many retail stores that currently have EAS functionality to prevent shoplifting rely on bar code information for inventory control. RFID provides faster and more detailed inventory control than bar codes. Retail stores have paid much for reusable hard tags. The increased cost can be easily compensated for since the incorporation of RFID technology into EAS hard tags can improve inventory control capability and improve loss prevention.

Disclosure of Invention

It is an object of the present disclosure to provide a tag or label in which the features of a separate EAS tag or label and a separate RFID tag or label are combined in one tag or label.

More particularly, the present disclosure relates to a security tag that includes an EAS component having a defined surface area and an RFID component having a defined surface area. The defined surface area of the EAS component is configured to at least partially overlap the defined surface area of the RFID component.

The RFID component includes an antenna, and the antenna may at least partially overlap the defined surface area of the EAS component. A substantially planar spacer having a thickness may be at least partially located between the defined surface area of the EAS component and the defined surface area of the RFID component. The thickness of the spacer determines a read range between the RFID reader and the RFID component, and the RFID reader is capable of activating the RFID component when the RFID component is within the read range. The antenna and the EAS component may form part of an impedance matching network of the antenna. The antenna impedance may include a loading effect of the EAS component. The RFID component may include an antenna and an Application Specific Integrated Circuit (ASIC). The ASIC may have a complex impedance. The complex impedance of the ASIC may be matched to the coupled complex conjugate impedance of the antenna including the load effects of the EAS component. The material of the base portion of the RFID component may be selected from the group consisting of: (a) base paper; (b) polyethylene; (c) a polyester; (d) polyethylene terephthalate (PET); and (e) Polyetherimide (PEI). The base portion material may be a plastic having a dielectric constant of about 3.3 and a loss tangent of less than about 0.01. The spacer material may be selected from the group consisting of: (a) a low loss, low dielectric constant material; and (b) air.

The present invention also relates to a method of manipulating a combination of an Electronic Article Surveillance (EAS) component and a Radio Frequency Identification (RFID) component. The method comprises the following steps: the RFID component is moved to overlap the EAS component to change the impedance of an antenna coupled to the RFID component. The impedance of the antenna includes the loading effects of the EAS component. The antenna may include an antenna conductor, and the antenna may be configured by cutting the antenna conductor into at least two sections such that at least one section point corresponds to an antenna operating frequency based on a length of the at least two antenna sections; and isolating the cut antenna conductor from the remainder of the conductor to tune the antenna.

The method may further include combining an Electronic Article Surveillance (EAS) component and a Radio Frequency Identification (RFID) component having a spacer therebetween, the spacer having a thickness, and the method may include the step of varying the thickness of the spacer. The step of varying the thickness of the spacer may vary a read range between the RFID reader and the RFID component, and wherein the RFID reader is capable of activating the RFID component when the RFID component is within the read range.

Drawings

The subject matter regarded as the embodiments is particularly pointed out and distinctly claimed in the concluding portion of the specification. However, the embodiments of the invention, both as to organization and method of operation, together with objects, features, and advantages thereof, may best be understood by reference to the following detailed description when read with the accompanying drawings in which:

FIG. 1 illustrates a combination RAS/RFID security tag according to one embodiment of the present disclosure;

FIG. 2A illustrates a portion of sample test data for a combined RAS/RFID security tag according to one embodiment of the present disclosure;

FIG. 2B illustrates another portion of sample test data for a combined RAS/RFID security tag according to one embodiment of the present disclosure;

FIG. 3A illustrates an RFID system utilizing magnetic field coupling according to one embodiment of the present disclosure;

FIG. 3B illustrates an RFID system utilizing electric field coupling in accordance with one embodiment of the present disclosure;

FIG. 4 illustrates a perspective exploded view of a security tag according to one embodiment of the present disclosure;

FIG. 5 illustrates a top view of the security tag of FIG. 4;

FIG. 6 illustrates a top view of a security tag with an antenna having segment points, in accordance with an alternative embodiment of the invention;

FIG. 7 illustrates a block flow diagram in accordance with one embodiment of the present disclosure;

FIG. 8A illustrates a prior art configuration of a coplanar EAS tag adjacent to an RFID tag;

FIG. 8B illustrates a prior art configuration of coplanar EAS tags and RFID tags separated by a gap;

FIG. 8C illustrates an embodiment of the present disclosure combining an EAS component with an RFID component mounted directly below the EAS component;

FIG. 8D illustrates an embodiment of the present disclosure of a portion of an Anjin tag combining an EAS component with an RFID component insert;

FIG. 8E is a front view of the embodiment of the present disclosure of FIG. 8D;

FIG. 8F illustrates an embodiment of the present disclosure of a portion of a security tag combining an EAS component with an RFID component insert; and

fig. 8G is a front view of the embodiment of the disclosure of fig. 8F.

Detailed Description

The entire contents of PCT application No. [ attorney docket No. F-TP-00071], commonly owned AND filed concurrently WITH PCT application No. R.Copeland entitled "COMBINATION EAS AND RFIDABEL OR TAG WITH CONTROL READ RANGE", is incorporated herein by reference.

The present disclosure will be understood more fully from the detailed description given below of specific embodiments of the invention taken in conjunction with the accompanying drawings, which, however, should not be taken to limit the invention to the specific embodiments, but are for explanation only.

Numerous specific details are set forth herein to provide a thorough understanding of the many possible embodiments that make up the combination EAS/RFID tag of the present disclosure. However, it will be understood by those of ordinary skill in the art that the embodiments may be practiced without these specific details and that in other instances, well-known methods, procedures, components, and circuits have not been described in detail so as not to obscure the embodiments. It can be appreciated that the specific structural and functional details disclosed herein may be representative and do not necessarily limit the scope of the embodiments.

Some embodiments may be described using the terms "coupled" and "connected," along with their derivatives. For example, some embodiments may be described using the term "connected" to indicate that two or more elements are in direct physical or electrical contact with each other. In another example, some embodiments may be described using the term "coupled" to indicate that two or more elements are in direct physical or electrical contact. However, the term "coupled" may also mean that two or more elements are not in direct contact with each other, but yet still co-operate or interact with each other. Embodiments disclosed herein are not necessarily limited in this regard.

It is worthy to note that any reference in the specification to "one embodiment" or "an embodiment" means that a particular feature, structure, or characteristic described in connection with the embodiment is included in at least one embodiment. The appearances of the phrase "in one embodiment" in various places in the specification are not necessarily all referring to the same embodiment.

Turning now to the details of the present disclosure. One way in which a combination EAS/RFID tag (or label) may be used is to bring both the EAS-related component and the RFID-related component together and package them together. However, there may be some electrical or electromechanical interaction factors that may affect the performance of the EAS function and/or the RFID function. Placing the RFID tag on top of the EAS tag is the most traditional way, but can result in severe detuning and signal loss of the RFID tag. For example, in a typical RFID device, the performance of the RFID tag is typically very sensitive to impedance matching of the Application Specific Integrated Circuit (ASIC)/lead frame assembly of the RFID device to the effective impedance of the RFID antenna mounted on the substrate. A more detailed description of some possible embodiments of the RFID portion of the device is discussed further below. Other objects surrounding the RFID tag may have an effect on the effective impedance or absorption of electromagnetic energy for reading the RFID tag.

Some existing 2450MHz EAS/RFID combination tags use a configuration in which the RFID tag and the EAS tag are in an overlapping configuration. There may be a severe degradation in the detection of RFID tags for this particular application. Although end-to-end or a small overlap is most suitable for such systems, in these cases the sign size tends to become very large. Furthermore, it is known that side-by-side configurations can form irregular RFID detection maps. There are few designs on the market that can successfully implement a combination EAS/RFID tag. Most applications of combination EAS and RFID tags using branding products use separate EAS and RFID tags that are separately mounted, causing them to occupy a greater amount of space on the branding product than each would occupy separately.

It is envisioned that a solution to this problem would be to use the EAS tag portion of the combination tag as part of the impedance matching network of the RFID tag. For example, as the RFID tag is placed closer to the EAS tag, the RFID tag antenna impedance is affected or adjusted by the EAS tag. To achieve RFID tag impedance matching, the RFID antenna geometry itself may be designed to take into account any eventual electrical effect of the EAS tag on the impedance. For example, an RFID antenna may be configured to have a high capacitive impedance and may be severely mismatched with the impedance of the device's logic chip (e.g., the ASIC/leadframe assembly referred to above). With the RFID tag placed near the EAS tag, e.g., directly below the EAS tag, the impedance of the RFID antenna nearly matches the ASIC impedance.

FIG. 1 illustrates generally an EAS component 1 and an RFID component 2. The EAS component 1 is an EAS tag or label. The EAS component 1 may include, but is not limited to, for example, a magnetic resonator element and a bias magnet (or other EAS type resonant circuit) contained in a housing of plastic or some other material. Other EAS tags or labels not specifically disclosed herein may also perform the functions of the EAS component 1. The RFID component 2 is an RFID tag or label. For purposes of the discussion of FIG. 1, the RFID component 2 may include, but is not limited to, for example, an antenna mounted on a substrate material, and an ASIC-based RFID logic circuit or processing chip attached to the antenna, as best shown in FIG. 4 discussed below. Other RFID tags or labels not specifically disclosed herein may also perform the function of RFID component 2. In a particularly useful embodiment, the RFID portion of the system, RFID unit 2, operates in the ISM band of 868MHz and/or 915 MHz. However, one of ordinary skill in the art will readily recognize that the invention is not so limited and may be used in any other available frequency.

When the EAS component 1 and the RFID component 2 are placed adjacent to each other, as shown in location "P1" of FIG. 1, the EAS component 1 has only a small effect on the antenna impedance of the RFID component 2. However, as shown by the positions "P2", "P3", and "P4", i.e., the degree of overlap shown by shaded area 3, the effect on RFID antenna impedance increases as RFID component 2 is progressively located beneath EAS component 1.

More specifically, tag positions P1-P4 of RFID component 2 are configured to:

P1-EAS component 1 and RFID component 2 are disposed adjacent to each other;

p2 ═ RFID component 2 is disposed to intersect 1/4 with EAS component 1 and below EAS component 1;

p3 ═ RFID component 2 is disposed to intersect 1/2 with EAS component 1 and below EAS component 1; and

p4 ═ RFID component 2 is disposed directly below EAS component 1.

For example, FIGS. 2A and 2B show the results of testing the real and imaginary parts of the RFID antenna impedance as a function of frequency over the ISM band of 915MHz for a sample security tag that includes EAS component 1 and RFID component 2.

As shown in fig. 2A, at the center frequency of 915MHz, as the RFID tag 2 moves from the position P1 to the position P4, the real impedance R changes from R1 to about 6 Ω to R4 to about 13 Ω. This significant increase in real impedance R represents an increase in effective loss caused by the EAS tag material. Accordingly, as RFID tag 2 moves from position P1 to position P4, the imaginary impedance Z changes from Z1 ═ 125 Ω to Z4 ═ 195 Ω. Therefore, the imaginary impedance Z changes from somewhat capacitive to inductive.

The RFID component 2 may be designed such that the antenna impedance approximates the complex conjugate of the ASIC device. This results in resonance at a target frequency such as, for example, 915 MHz. The impedance test results for the ASICRFID device with the lead frame used in this example, the chip manufactured by ST Microelectronics of Geneva, Switzerland, were 5-j140 Ω, and for the ASIC RFID device with the lead frame used in this example, the chip manufactured by Koniklikje Philips Electronics N.V. of Amsterdam, the Netherlands, were 20-j270 Ω. For both RFID devices, the RFID tag antenna imaginary impedance Z must be in the range of + j (140 to 270) Ω in order to resonate at the target frequency.

Thus, the impedance of the EAS component may be used to design a combination RFID/EAS security tag for matching purposes. The RFID component antenna may be designed to have a negative imaginary impedance and achieve an appropriate positive imaginary impedance when placed directly under, over, or near the EAS component. As will be appreciated by the present disclosure, such a configuration may be used with various magnetostrictive stickers and EAS hard tags, such as those manufactured by the sensory Corporation of America (sensory Corporation, a division of Tyco Fire and Security, LLC of Boca Raton, Florida)Any type of EAS tag or label. However, the type of EAS device is not limited to these specific examples.

The RFID components may include, for example, semiconductor Integrated Circuits (ICs) and tunable antennas. The tunable antenna can be tuned to a desired operating frequency by adjusting the length of the antenna. Although these embodiments may be particularly useful for the Ultra High Frequency (UHF) spectrum, the range of operating frequencies may vary. Depending on the application and the size of the area available for the antenna, the antenna may be tuned within a few hundred megahertz (MHz) or higher, such as 868-950MHz, for example. For example, in one embodiment, the tunable antenna may be tuned to operate within an RFID operating frequency such as the 868MHz band used in Europe, the 915MHz Industrial, scientific and medical (ISM) band used in the United states, and the 950MHz band proposed in Japan. It is again noted that these operating frequencies are given by way of example only, and the embodiments are not limited in this regard.

For example, in one embodiment, the tunable antenna may have a unique antenna geometry that may be used for an inward spiral pattern for RFID applications or EAS applications. The inward spiral pattern may cause the antenna traces to form a nest, thereby returning the traces to the origin. This may result in an antenna that is similar in function to a conventional half-wave dipole antenna, but with a smaller overall size. For example, the size of a conventional half-wave dipole antenna at 915MHz is approximately 16.4 centimeters (cm) long. In contrast, some embodiments may provide an antenna having a shorter length of approximately 3.81cm, performing the same as a conventional half-wave dipole antenna at an operating frequency of 915 MHz. In addition, the ends of the antenna traces may be modified to tune the antenna to a desired operating frequency. Since the ends of the antenna traces are inward from the perimeter of the antenna, tuning can be accomplished without changing the antenna geometry.

FIG. 3A illustrates a first system in accordance with one particularly useful embodiment of the present disclosure. Fig. 3A shows an RFID system 100 that may be configured to operate with an RFID component 2, the operating frequency of the RFID component 2 being within a High Frequency (HF) band that is considered to be up to and including a frequency of 30 MHz. In this frequency range, the main component of the electromagnetic field is the magnetic field. However, RFID system 100 may also be configured to operate RFID component 2 with other portions of the RF spectrum as desired for a given implementation. The embodiments are not limited in this regard. For example, RFID component 2 may partially overlap EAS component 1.

RFID system 100 may include a plurality of nodes. The term "node" as used herein refers to a system, unit, module, circuit board or device that can process signals representing information. The signal type may be, for example, but not limited to, electrical, optical, acoustical and/or chemical in nature. Although fig. 3 shows a limited number of nodes, it should be appreciated that any number of nodes may be used in RFID system 100. The embodiments are not limited in this regard.

Referring initially to FIG. 4, FIG. 4 illustrates a side view of a security tag 200 in accordance with a particularly useful embodiment of the invention. The RFID component 2 includes a base portion or substrate 202 having a first surface or surface region 202a and a second surface or surface region 202b, the first surface or surface region 202a and the second surface or surface region 202b being generally on opposite sides of the base portion or substrate 202. An antenna 204 is located on the substrate 202. Antenna 204 has a first surface or surface area 204a and a second surface or surface area 204b that are generally on opposite sides of antenna 204. A lead frame 206 is located on the antenna 204 and an application specific semiconductor integrated circuit (ASIC)208 is located on the lead frame 206. The first and second surfaces or surface areas 202a and 202b, 204a and 204b are defined surface areas of the RFID component 2.

Security tag 200 includes a substantially planar covering material or spacer 210 positioned over RFID component 2 and an EAS component 1 positioned over spacer 210. The spacer 210 has surfaces or surface regions 210a and 210b on opposite sides thereof.

The EAS component 1 has a first surface or surface area 1a and a second surface or surface area 1b generally on opposite sides of the EAS component 1. The first and second surfaces or surface areas 1a and 1b are defined surfaces or surface areas of the EAS component 1.

For reference, security tag 200 is illustrated as being directly below EAS component 1, i.e., in position P4 of FIG. 1. The security tag 200 is shown in position 4 for example only and may be in any position relative to the EAS tag 1 as discussed above with reference to fig. Security tag 200 may also be used entirely independently of EAS tag 1 or in combination therewith. The embodiments are not limited in this regard.

More specifically, security tag 200 includes an EAS component 1 having one of defined surface areas 1a and 1b and an RFID component 2 having one of defined surfaces or surface areas 202a, 202b, 204a, and 204 b. At least one of the defining surfaces or surface areas 1a and 1b of the EAS component 1 is configured to at least partially overlap at least one of the defining surfaces or surface areas 202a, 202b, 204a and 204b of the RFID component 2. RFID component 2 may include an antenna 204 that at least partially overlaps at least one of the defining surfaces or surface areas 1a and 1b of EAS component 1.

In one embodiment, the defined surface or surface area of RFID component 2 is one of surfaces or surface areas 202a and 202 b.

The substantially planar spacer 210 has a thickness "t" and is located at least partially between at least one of the defined surfaces or surface areas 1a and 1b of the EAS component 1 and at least one of the defined surfaces or surface areas 202a, 202b, 204a, and 204b of the RFID component 2.

Although FIG. 4 illustrates a limited number of elements, it should be appreciated that more or fewer elements may be used with security tag 200. For example, attachable and removable liners may be incorporated into security tag 200 to facilitate attaching security tag 200 to an object to be monitored. Those of ordinary skill in the art will recognize that semiconductor IC208 may be soldered directly to antenna 204 without lead frame 206.

Returning now to FIG. 3A, RFID system 100 may also include RFID reader 102 and security tag 200. Security tag 200 is physically separated from RFID reader 102 by a distance dL As will be described below with reference to FIG. 4, security tag 200 is an RFID security tag, label or label that differs from the prior art by including an EAS component, i.e., an EAS label or tag. The RFID component 2 comprises a resonant circuit 112. The resonant circuit 112 includes an inductor L2 and a resonant capacitor C2 connected across terminals T1 and T2 of the ASIC 208. The capacitance of ASIC 208 is generally negligible compared to C2. If additional capacitance is required to be added to resonant circuit 112 to enable the antenna, i.e. inductor L2, to be tuned to the appropriate frequency, capacitor C2 is connected in parallel with inductor L2 so that resonant circuit 112 becomes such that an induced voltage V can be developed across it_iAnd terminals T1 and T2. Terminals T1 and T2 are coupled to other portions of RFID component 2, as described below with reference to FIG. 4. In addition, the inductance value of the inductor coil or antenna L2 includes the inductance presented by the EAS tag or label.

RFID reader 102 may include a tuned circuit 108 having an inductor L1, with inductor L1 serving as an antenna for RFID reader 102. In the event that additional capacitance needs to be added to the tuning circuit 108 to enable proper tuning of the inductor or antenna L1, a capacitor C1 is connected in series with the inductor or antenna L1. RFID reader 102 is configured to generate pulsed or Continuous Wave (CW) RF power across tuned circuit 108, electromagnetically coupled by alternating current interaction with parallel resonant circuit antenna 112 of RFID component 2. The mutually coupled electromagnetic power from RFID component 2 couples to RFID reader 102 through magnetic field 114.

RFID component 2 is a power conversion circuit that converts CW RF electromagnetic power coupled by a portion of magnetic field 114 into direct current signal power for use by logic circuits of a semiconductor IC to implement RFID operation of RFID component 2.

RFID component 2 may also be an RFID security tag that includes a memory that stores RFID information and transmits the stored information in response to interrogation signal 104. The RFID information may include any type of information that can be stored in memory for use by RFID component 2. Examples of RFID information include a tag unique identifier, a system unique identifier, an identifier of an object being monitored, and the like. The type and amount of RFID information is not limited in this regard.

RFID component 2 may also be a passive RFID security tag. Passive RFID security tags do not use an external power source, but rather use the interrogation signal 104 as a power source. The detection zone Z1 is defined as the volume of imaginary space generally bounded by a generally spherical surface having a radius R1 from the inductor L1. Radius R1 defines a detection distance or read range R1 such that if distance d1 is less than or equal to read range R1, RFID reader 102 induces a desired threshold voltage V between terminals T1 and T2_TTo activate RFID component 2. The read range R1 depends on, among other factors, the strength of the EM field radiation and the magnetic field 114 from the tuned circuit 208. Thus, the intensity of the EM field radiation 114 determines the read range R1.

The RFID component 2 may be activated by a dc voltage formed as a result of rectifying the input RF carrier signal including the interrogation signal 104. An RFID component 2 is activated which can then transmit the information stored in its memory register via a response signal 110.

In normal High Frequency (HF) operation, when the resonant circuit 112 of the RFID system 100 is in proximity to the tuned circuit 108 of the RFID reader 102, an Alternating Current (AC) voltage V is formed between terminals T1 and T2 of the parallel resonant circuit 112 of the RFID component 2_i. AC voltage V across resonant circuit 112_iIs rectified to a Direct Current (DC) voltage by a rectifier and when the magnitude of the rectified voltage reaches a threshold V_TThen RFID component 2 is activated. The rectifier is the above-mentioned special integrationAn electrical circuit (ASIC) 208. Once activated, RFID component 2 transmits the stored data in its memory register by modulating interrogation signal 104 of RFID reader 102 to form response signal 110. The RFID device 106 then transmits a response signal 110 to the RFID reader 102. RFID reader 102 receives response signals 110 and converts them into a detected serial data word bit stream of data representing information from RFID component 2.

The RFID system 100 shown in fig. 3A may be considered a High Frequency (HF) RFID system because the RFID reader 102 is inductively coupled to the RFID component 2 via the magnetic field 114. In HF applications, antenna 204 is typically an inductive coil type antenna as provided by inductive coil L2.

Fig. 3B illustrates an Ultra High Frequency (UHF) system 150 in which an RFID reader 150 is coupled by an electric field E to an RFID device, tag or label 156 spaced a distance d2 apart. The UHF band is considered herein to be from about 300MHz to about 3 GHz. The UHF range includes, inter alia, frequencies in the 868MHz band, the 915MHz band and the 950MHz band.

For UHF applications, antenna 204 of RFID component 2 typically comprises a UHF open ended dipole antenna, while RFID reader 152 typically comprises a patch antenna. A coaxial feed from the reader 152 is connected to the patch antenna. The UHF antenna may be a simple half-wave dipole or a patch antenna. Many popular designs use a small patch antenna backed by a gas filled cavity that can be linearly or circularly polarized. For the circular polarization case, electric field vectors E1 and E2 rotate at the same magnitude. Linearly polarized antennas have high E-field amplitudes in certain orthogonal orientations that may be suitable for certain RFID tag orientations.

Thus, in UHF applications, antenna 204 of RFID component 2 comprises an open ended dipole antenna, while in HF applications, it is typically inductor L2.

In general, when operating in the UHF range, RFID component 2 need not include a capacitor, such as C2, in parallel with open ended dipole antenna 204 in order to be able to tune to the frequency transmitted by the patch antenna of RFID reader 152.

Returning to FIG. 4, as beforeAs noted, RFID component 2 may include a base portion or substrate 202, with base portion or substrate 202 including any type of material suitable for mounting antenna 204, lead frame 206, and IC 208. For example, the material of the substrate 202 may include base paper, polyethylene, polyester, polyethylene terephthalate (PET), Polyetherimide (PEI) (e.g., sold by General Electric Co. of Fairfield, Connecticut, USA)Amorphous thermoplastic PET) and/or other materials. It is well known that the particular material implemented for substrate 202 may affect the RF performance of security tag 200, and as such, the dielectric constant and loss tangent may characterize the dielectric properties of an appropriate substrate material for use as substrate 202.

In general, a higher dielectric constant may cause a larger frequency shift of the antenna than free space where no substrate is present. Although the antenna may be retuned to the original center frequency by physically changing the antenna pattern, it is preferable to use a material with a high dielectric constant and low dielectric loss because the use of such a material results in a tag or label of a smaller size. The term "read range" may refer to the communication operating distance between RFID reader 102 and security tag 200. Examples of read ranges for security tag 200 may range from 1 meter to 3 meters, although embodiments are not limited in this regard. The loss tangent may characterize the absorption of RF energy by the medium. The absorbed energy may be lost in the form of heat and not available to the ASIC 208. The loss of energy may cause the same effect as reducing the transmission power, and thus the read range can be reduced. Therefore, it is desirable to minimize the loss factor in substrate 202, since it cannot be "tuned out" by adjusting antenna 204. The total frequency shift and RF loss also depend on the thickness of the substrate 202. As the thickness increases, the frequency shift and loss also increase.

For example, in one embodiment, the substrate 202 may be configured with a base paper having a dielectric constant of about 3.3 and a loss tangent of about 0.135. The loss of the base paper is relatively large at 900 MHz. The more lossy material has a dielectric loss tangent greater than about 0.01. In one embodiment, substrate 202 may be constructed of a plastic having a dielectric constant of about 3.3 and a loss tangent of about 0.001. The embodiments are not limited in this regard.

In one embodiment, security tag 200 may include an IC208 having a semiconductor IC such as an RFID chip or an Application Specific Integrated Circuit (ASIC) ("RFID chip"). RFID chip 208 may include, for example, an RF or Alternating Current (AC) rectifier that converts RF or AC voltage to DC voltage, a modulation circuit for transmitting stored data to an RFID reader, a storage circuit that stores information, and logic circuits that control all functions of the device. In one embodiment, RFID chip 208 may be configured to use an I-CODE high frequency Smart tag (HSL) RFID ASIC or a U-CODE ultra high frequency Smart tag (HSL) RFID ASIC both manufactured by Philips semiconductor of Amsterdam, the Netherlands, or an XRA00RFID chip manufactured by ST Microelectronics of Geneva, Switzerland. However, the embodiments are not limited in this regard.

A lead frame is a small connection that allows an RFID chip, such as RFID chip 208, to be attached to an antenna, such as antenna 204. In one embodiment, RFID chip 208 may be soldered directly to antenna 204 without including lead frame 206. Lead frame 206 may also include a die mounting paddle or flag and a plurality of lead fingers. The die paddle is primarily used to mechanically support the die during housing manufacture. The lead fingers connect the die to circuitry outside the housing. One end of each lead finger is typically connected to a pad on the die by wire bonding or tape automated bonding. The other end of each lead finger is a lead that is mechanically and electrically connected to the substrate or circuit board. Lead frame 206 may be made from sheet metal by stamping or etching, often followed by finishing operations such as plating, underpass (down set), and taping. For example, in one embodiment, leadframe 206 may utilize, for example, the sensory EAS Microlabel manufactured by the sensory Corporation of the United states (sensory Corporation, a division of Tyco Fire and Security, LLC of Boca Raton, Florida)^TMA lead frame. However, the embodiments are not limited in this regard.

In one embodiment, antenna 204 includes an inductive coil L2 and, if desired, a capacitor C2 of resonant circuit 112 of RFID component 2. Terminals T1 and T2 are also included in antenna 204 to couple with RFID chip 208 to induce a voltage V_iOnce the threshold voltage V is reached_TThe RFID component 2 can be activated.

In one embodiment, antenna 204 generally comprises an open ended dipole antenna for RFID component 2 for UHF applications. Terminals T1 and T2 are also included in antenna 204 to couple with RFID chip 208 to enable electric field E to excite the antenna of reader 152.

In one embodiment, security tag 200 may also include a cover or spacer material 210 applied to the top of the finished security tag. As with substrate 202, cover or spacer material 210 may also affect the RF performance of RFID component 2. For example, the cover material 210 may be implemented using a cover stock having a dielectric constant of about 3.8 and a loss tangent of about 0.115. The embodiments are not limited in this regard.

More specifically, as previously described, the substantially planar spacers 210 have a thickness "t". When security tag 200 is a hard combination tag, thickness "t" is typically about 1mm to 2mm, whereas when security tag 200 is a combination tag, thickness "t" is much less than 1 mm. As previously described, the spacer 210 has surfaces or surface regions 210a and 210b on opposite sides thereof. In one embodiment, the spacer surfaces or surface regions 210a and 210b are parallel to each other. The EAS component 1 at least partially overlaps at least one of the spacer surfaces or surface areas 210a and 210 b.

An RFID interposer is a term commonly found in the art and may be defined herein as an RFID component 2, including a combination of a substrate 202, an antenna 204, a lead frame 206 (if applicable), and an RFID chip 208. RFID component 2 at least partially overlaps the other of spacer surfaces 210a and 210 b. Security tag 200 includes RFID insert or component 2 and spacer 210.

Security tag 200 may also include antenna 204. Antenna 204 may represent, for example, antenna 112 of RFID device 106, or antenna 204 may be formed from an LC parallel resonant circuit, where L is inductance and C is capacitance. Alternatively, antenna 204 may also be a tunable antenna tuned to the carrier signal to maximize the voltage across the antenna circuit. It will be appreciated that this will extend the read range of antenna 204. As is well known, the accuracy of the tuning circuit is related to the spectral width of the carrier signal transmitted by the transmitter 102. For example, in the United states, the Federal Communications Commission (FCC) currently regulates one band of the RFID security tag spectrum to 915 MHz. Therefore, transmitter 102 should transmit the query signal at approximately 915 MHz. To receive the query signal, antenna 204 should be narrowly tuned to the 915MHz signal. For 915MHz applications, RFID tag antenna 204 may be printed, etched, or plated.

The EAS tag 1 creates or presents a constant load impedance to the RFID component 2. As a result, the antenna 204 of the RFID tag 200 uses this constant load of the EAS tag 1 for impedance matching. More specifically, the antenna 204 has a complex impedance and the EAS component 1 forms part of the antenna's impedance matching network. Thus, the impedance of antenna 204 includes the loading effect of EAS component 1. That is, the loading effect of the EAS component 1 is the constant load impedance of the EAS component 1. The loading effect of the EAS component 1 may be altered by replacing or exchanging one material having one dielectric constant and loss tangent with another material having another dielectric constant and loss tangent that is included in the EAS component 1.

The RFID component chip 208 may be represented as an equivalent RC series circuit, where R represents a resistor and C represents a capacitor. The complex impedance Z for this circuit_chipExpressed as:

Z_chip＝Z₁-jZ₂，

wherein Z is₁And Z₂Are the real and imaginary parts of the impedance of the chip 208. The RFID device tag or label antenna 204 may use a complex impedance Z_antennaExpressed as:

Z_antenna＝Z₃+jZ₄，(1)

wherein Z is₃And Z₄Are the real and imaginary parts of the impedance of the antenna 204. When chip 208 is mounted on antenna 204, the complex impedance of chip 208 is matched to the coupled conjugate impedance of RFID antenna 204, which includes the impedance matching effect or load effect of EAS component or tag 1. This maximizes the power coupled to the RFID chip 208, resulting in a maximum read range R1.

In one embodiment, the thickness "t" of the spacer 210 may be changed relative to the RFID reader device 102 or the RFID reader device 152 to change the read range R1, respectively. More specifically, thickness "t" determines the read range, i.e., the maximum distance R1 between security tag 200 and EAS/RFID reader 102 or EAS/RFID reader 152 at which reader 102 or 152 can interrogate security tag 200. The read range R1 is negatively affected as the thickness "t" decreases. In contrast, the read range R1 expands as the thickness "t" increases. It should be noted that reader 102 for HF applications and reader 152 for UHF only read either EAS component 1 or RFID component 2 so that EAS component 1 is read by a dedicated EAS reader and RFID component 2 is read by a dedicated RFID reader. Alternatively, reader 102 and reader 152 may be combined in the same housing or have their functions combined to be performed by the same hardware. Because of the large difference between the read frequency range common to EAS components and the read frequency range common to RFID components, EAS components typically read at frequencies in the range of less than or equal to 8.2KHz, while RFID components typically read at frequencies in the range of greater than or equal to 13MHz, undesirable interference between reading EAS component 1 and reading RFID component 2 is prevented or minimized.

However, it is envisioned that, because security tags 200 and 400 are separate devices, security tags 200 and 400 provide EAS functionality and RFID functionality independent of the type of reader or the particular frequency to which security tag 200 or 400 is subjected.

The separator 210 may be manufactured by using, for example, Emerson cutting Microwave Products, Inc. (Emerson cutting Mi, USA)crown Products, Inc. of Randolph, Massachusetts) manufactured by crown Products, IncA low loss, low dielectric material of a rigid foam or any other similar material. The embodiments are not limited in this regard. When made of one of the foregoing materials, the read range is about 30.5 to 61.0cm (1 to 2 feet) when the thickness "t" of the spacer 902 is about 0.0762mm (0.003 inches). Similarly, when the thickness "t" of the spacer 210 is at least 1.02mm (0.040 inches), the read range is about 127cm (5 feet).

In one embodiment, spacer 210 may be a film having a thickness "t" of about 0.05mm, wherein EAS component 1 completely overlaps RFID component 2.

In one embodiment, the spacer 210 may be air, wherein the EAS tag 1 is mechanically supported off the RFID component 2.

As a result, security tag 200 provides significant advantages over the prior art by allowing the space or volume of the combination EAS/RFID device to be significantly reduced and the cost to be reduced.

In one embodiment, security tag 200 may use the induced voltage from the coil antenna for operation. This AC induced voltage may be rectified to produce a DC voltage. When the DC voltage reaches a certain level, the RFID component 2 starts to operate. By providing an energizing RF signal via transmitter 102, RFID reader 102 may communicate with remote security tag 200 without an external power source, such as a battery.

Since the excitation and communication between the RFID reader and RFID component 2 is accomplished through antenna 204, antenna 204 may be tuned for improved RFID applications. RF signals can be radiated or received efficiently if the linear dimensions of the antenna are comparable to the wavelength of the operating frequency. However, the linear scale may be larger than the available surface area available for antenna 204. Thus, it may prove difficult to utilize a true full size antenna in HF applications in the limited space that holds true for most RFID systems. It is thus envisaged that the RFID component 2 may use a smaller LC loop antenna circuit arranged to resonate at a given operating frequency. The LC loop antenna may include, for example, a spiral coil and a capacitor. Spiral coils are typically formed from n turns of wire, or n turns of printed or etched inductors on a dielectric substrate.

For HF applications, to achieve good RFID coupling, the product of the loop area x turns and the resonant frequency needs to be optimized. In one embodiment of the present disclosure as shown in FIG. 3A, the resonant frequency may be affected by tuning the parallel capacitor C2 of the resonant circuit 112 including the effect on the impedance of the EAS tag 1 and the RFID chip 208.

In HF or UHF applications, the RFID chip complex impedance must be matched by the complex conjugate impedance of the antenna including the loading effect on the EAS tag's impedance for the particular frequency of interest. In the case of HF, a resonant capacitor is typically used to tune the frequency. This capacitor is typically larger than the RFID chip capacitance and will dominate the response. For the UHF case, the RFID chip complex impedance contains only the chip capacitance for tuning.

In another embodiment according to the present disclosure, antenna 204 may be designed such that the complex conjugate impedance of the entire antenna matches the complex impedance of leadframe 206 and IC208 at a desired operating frequency, e.g., 915 MHz. However, when RFID security tag 200 is positioned on an object to be monitored, it is observed that the resulting operating frequency may change, i.e., each object may have a substrate material with dielectric properties that affect the RF performance of antenna 204. In other words, like substrate 202, the substrate of the object may cause a frequency shift and RF loss determined by the dielectric constant, loss tangent, and material thickness. Examples of different object substrates may include so-called "chip board" (i.e., material for product-grade cartons, corrugated fiberboard as material for corrugated cartons), video tape and Digital Video Disk (DVD) boxes, glass, metal, and the like. It is contemplated that each object substrate may have a significant impact on the read range R1 of security tag 200.

Antenna 204 is tunable to compensate for this variation. In other words, because many materials have dielectric constants greater than 1, the operating frequency is typically reduced when security tag 200 is attached to an object substrate. Antenna 204 is typically modified in some way to establish the original frequency, otherwise detection performance may be degraded and read range may be reduced. In this way, antenna 204 may be modified by trimming the ends of antenna 204 by cutting the antenna conductor and separating the resulting trimmed antenna segments from the cut ends. However, the trimmed ends are not necessarily removed to provide a tuning operation. Thus, continuous tuning of antenna 204 to a desired operating frequency may enable security tag 200 to operate when security tag 200 is attached to various objects. Security tag 200 in general and antenna 204 in particular are described in more detail below with reference to fig. 5-7.

FIG. 5 illustrates a top view of a local security tag 200 with an antenna that is particularly suited for UHF applications, in accordance with one embodiment consistent with the present disclosure. Security tag 200 includes an antenna 204 positioned on a substantially rectangular substrate 202. In one envisioned embodiment, the antenna 204 is located on the substrate 202 by die cutting the tag antenna pattern onto the substrate 202.

RFID chip 208 may be connected to lead frame 206 by ultrasonically bonding lead frame 206 to conductive pads on RFID chip 208. In the particular embodiment of fig. 5, RFID chip 208 and lead frame 206 are located at the geometric center of the dielectric substrate material of substrate 202. The ends of lead frame 206 are mechanically and electrically bonded to the foil-made antenna pattern of antenna 204. A cover material (not shown) may be applied to the entire upper surface of security tag 200 to protect the components and, if desired, provide a surface for printed indicia. As is well known in the art, RFID chip 208 is bonded to antenna 204 using an anisotropic conductive thermoset adhesive. An example of such an adhesive is Loctite manufactured by Henkel Loctite Corporation of Rocky Hill, Connecticut, USAAntenna 204 may also includeA plurality of antenna portions. For example, antenna 204 may include a first antenna portion 306 and a second antenna portion 308, first antenna portion 306 being connected to first side 206A of lead frame 206, and second antenna portion 308 being connected to second side 206B of lead frame 206. Thus, antenna 204 is an entire RFID tag antenna subdivided into first antenna portion 306 and second antenna portion 308.

The first antenna portion 306 may have a first antenna end 306A and a second antenna end 306B. Similarly, second antenna portion 308 may have a first antenna end 308A and a second antenna end 308B. In one embodiment, as shown in fig. 5, first antenna end 306A of first antenna portion 306 is connected to lead frame 206A. First antenna portion 306 is located on substrate 202 forming an inwardly spiral pattern in a first direction from RFID chip 208, while second antenna end 306B is positioned to terminate on the inner loop of the inwardly spiral pattern. Similarly, first antenna end 308A of second antenna portion 308 may be connected to lead frame 206B. Second antenna portion 308 is also located on substrate 202 forming an inward spiral pattern in a second direction from RFID chip 208, and second antenna end 308B is positioned to terminate on the inner loop of the inward spiral pattern.

In one embodiment, the antenna geometry of antenna 204 is configured to rotate around the circumference of substrate 202 and spiral inward. It is conceivable that an inwardly spiraling antenna pattern may provide several advantages:

(1) the ends of the antenna 204 may be suitably positioned within the perimeter of the substrate 202. Placing the ends of antenna 204 within the perimeter of substrate 202 may allow the ends to be trimmed without changing the amount of area used by antenna 204.

(2) The Q factor of antenna 204 may be optimized such that the response of security tag 200, including the effects of spacer 210 and EAS tag 1, varies by only about-3 dB at the ISM band limit. Using Q1/(ka)³The Chu-Harrington limit of +1/(ka), where k is 2 pi/λ and "a" is a characteristic dimension of antenna 204, it can be seen that the sphere of radius "a" just surrounds security tag 200. Then, for a high Q factor, "ka" should be< 1. Thus, by maximizing Q, "a" is minimized to fall within the operating frequency band limits. Tuning of ANTENNA 204 for UHF applications is disclosed in further detail in co-pending, commonly owned U.S. patent application No. 10/917,752 entitled "TUNABLE ANTENNA" filed on 8/13 of 2004 by r.copeland and g.m. shafer, the entire contents of which are hereby incorporated by reference.

Particularly for UHF applications, antenna 204 may also be tuned to a desired operating frequency by modifying the first length of first antenna portion 306 and the second length of second antenna portion 308 after these antenna portions are disposed on substrate 202. For example, each antenna portion may be divided into multiple antenna segments at multiple segment points. The first and second antenna lengths may be modified by at least electrically isolating the first antenna segment from the second antenna segment. The antenna length may be modified by cutting each antenna portion at one of a plurality of segment points, each segment point corresponding to an operating frequency of antenna 204. Dividing first antenna portion 306 and second antenna portion 308 into multiple antenna segments results in shortening the length of each antenna portion and thereby effectively changing the overall inductance of antenna 204. The antenna segments and segment points are described in more detail below with reference to fig. 6.

FIG. 6 illustrates a diagram of a security tag 400 with an antenna having segment points, in accordance with one embodiment. In particular, FIG. 6 illustrates a top view of a portion of security tag 400 with a plurality of segment points SP1, SP2, SP3, and SP 4. In a manner similar to that shown in FIG. 4 for security tag 200, security tag 400 may include EAS component 1, spacer 210, and RFID component 2. Antenna 204 may also be tuned to a desired operating frequency by modifying a first length of first antenna portion 306 and a second length of second antenna portion 308 after these antenna portions are disposed on substrate 202. For example, it is contemplated that each antenna portion may be divided into a plurality of antenna segments at a plurality of segment points SP1-SP 4. The plurality of segment points SP1 through SP4 represent end tuning positions where antenna 204 may be cut or trimmed to tune to fit various objects. SP1 is the free space position where the length of the original free space antenna 204 was tuned to 868 MHz. SP2 is the free space position where the lengths of antenna portions 306 and 308 are tuned to 915 MHz. SP3 and SP4 are free space positions where the lengths of antenna portions 306 and 308 are tuned to fit various objects. Various objects include, for example, without limitation, retail and/or wholesale goods.

The first and second antenna lengths may be modified by at least electrically isolating the first antenna segment from the second antenna segment. The antenna length may be modified by cutting each antenna portion at one of a plurality of segment points, each segment point corresponding to an operating frequency of antenna 204. Severing may be accomplished in a number of different ways, such as cutting or punching the antenna trace at a given segment point SP1-SP 4. The severing may form slits such as slits 402, 404, 406, 408, 410, and 412 at the segment points.

It should be noted that for HF applications, antenna 204 is tuned by changing the inductance or capacitance parameters, rather than by changing the segment length.

In one embodiment, as shown in FIG. 6, each segment point SP1-SP4 corresponds to one operating frequency of antenna 204. In one example, SP1 may tune antenna 204 to an operating frequency of approximately 868MHz when security tag 400 is in free space and not attached to an object. SP2 may tune antenna 204 to an operating frequency of approximately 915MHz when security tag 400 is in free space and not attached to an object. SP3 may tune antenna 204 to an operating frequency of approximately 915MHz when security tag 400 is attached to a VHS tape cartridge. SP4 may tune antenna 204 to an operating frequency of approximately 915MHz when security tag 400 is attached to chipboard. It will be appreciated that the number of segment points and corresponding operating frequencies of antenna 204 may vary for a given implementation. The embodiments are not limited in this regard.

FIG. 7 illustrates a block flow diagram 500 in accordance with another embodiment of the present invention. As described above, security tag 200 may be configured in a number of different ways. For example: 1) in block 502, an integrated circuit may be connected to a leadframe; 2) in block 504, an antenna may be disposed on a substrate; and 3) in block 506, the lead frame may be connected to the antenna.

In one particular embodiment, in block 508, the antenna is tuned to a usable operating frequency. Tuning may be performed by modifying the length of the antenna by cutting the antenna into a plurality of antenna segments at segment points corresponding to the operating frequency. The cut-off may electrically disconnect the first antenna segment from the second antenna segment, thereby effectively shortening the length of the antenna.

As described above, the unique antenna geometry of the inwardly spiral pattern may be useful for RFID applications when connected to an RFID chip. However, as previously described, the unique antenna geometries shown in FIGS. 5 and 6 may also be used in EAS systems where security tag 200 and security tag 400 each include EAS component 1 and spacer 210, respectively. In one embodiment, RFID chip 208 may be replaced with a diode or other non-linear passive device having non-linear voltage and current characteristics. The antenna of the diode or other passive nonlinear EAS device may have the same geometry as shown in fig. 5 and 6 and be trimmed to tune the antenna to the operating frequency at which the transmitter is used to transmit interrogation signals for the EAS system. Similar to RFID system 100, the range of operating frequencies may vary, although these embodiments are particularly useful for UHF spectra such as 868-950 MHz. The embodiments are not limited in this regard.

It is also contemplated that some embodiments of the present disclosure may be configured with structure that may vary in accordance with any number of factors, such as: 1) the required calculation rate; (2) a power level; (3) a thermal tolerance; 4) processing a cycle budget; 5) an input data rate; 6) an output data rate; 7) a memory resource; 8) data bus speed and other performance constraints. For example, one embodiment may be configured using software executed by a general-purpose or special-purpose processor. In another example, an embodiment may be configured as dedicated hardware, such as a circuit, an ASIC, a Programmable Logic Device (PLD), or a Digital Signal Processor (DSP). In yet another example, an embodiment may be configured by any combination of programmed general-purpose computer components and custom hardware components. The embodiments are not limited in this regard.

Examples of Security tags 200 and 400 that are a combination EAS and RFID tag/label are shown in FIGS. 8A through 8D, and FIGS. 8A through 8D show Security tags such as those produced by the United states of Sensormatic (a division of Tyco Fire and Security, LLC of bocA Raton, Florida)Various types of magnetostrictive stickers and EAS hard tags. Fig. 8A illustrates an EAS tag 804 adjacent to an RFID tag 806 in a co-planar configuration. This adjacent arrangement of tags 804 and 806 is well known in the art. FIG. 8B illustrates a variation of the co-planar configuration of the EAS tag 804 and the RFID tag 806 of FIG. 8A, wherein the EAS tag 804 and the RFID tag 806 are separated from each other by a gap 805 of distance "g". Such a configuration in which 804 and 806 are separated by a gap 805 is also well known in the art.

In both the configurations of fig. 8A and 8B, the EAS tag 804 and the RFID tag 806 function independently of each other with respect to matching of impedance values. As "g" increases, the read range also expands. As a result, the size of the gap "g" controls the load impedance. However, this is not a desirable effect because, despite the extended read range, the total area occupied by the EAS tag 804 and the RFID tag 806 is increased, necessarily occupying more space or area on the object to be identified.

FIG. 8C illustrates an embodiment of the present disclosure of security tag 200 or 400 showing EAS component or label 1. An RFID component or insert 2 is mounted directly below the EAS component or tag 1. The pseudo barcode 802 is printed on the EAS component or tag 1 for visual purposes only. The pseudo barcode 802 does not have EAS or RFID functionality. The configuration of security tag 200 or 400 as an EAS component or tag 1 in combination with an RFID component or insert 2 mounted directly below (as shown in fig. 4) the EAS component or tag 1 provides minimal separation between the RFID component or insert 2 and the EAS tag 1 as compared to the prior art.

Fig. 8D illustrates one embodiment of the present disclosure for a portion 812 of a housing for combining an EAS component or tag 1 with an RFID component or insert 2. The RFID component or interposer 2 is defined to include an RFID chip 208 mounted on an antenna 204. However, neither the spacer 210 nor the adhesive layer is visible (see fig. 4).

Fig. 8E is a front view of the EAS component or tag 1 disclosed in fig. 8D in combination with the RFID component or insert 2, but showing the spacer 210 positioned between the EAS component or tag 1 and the RFID component or insert 2.

Fig. 8F illustrates one embodiment of the present disclosure for a portion 818 of a housing that combines an EAS tag 816, similar to EAS component or tag 1, and an RFID insert 814, similar to RFID component or insert 2. The RFID interposer 814 is defined as another RFID chip 820 mounted on the antenna 204. Again, neither the spacer 210 nor the adhesive layer is visible (see fig. 4).

Fig. 8G is a front view of the EAS tag 816 disclosed in fig. 8F in combination with the RFID insert 814, but showing the spacer 210 positioned between the EAS tag 816 and the RFID insert 814.

The type of EAS device and RFID combination is not limited to the EAS and RFID devices described herein.

While certain features of the embodiments have been illustrated as described herein, many modifications, substitutions, changes and equivalents will now 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 embodiments.

Claims (9)

1. A security tag, comprising:

an Electronic Article Surveillance (EAS) component having a defined surface area; and

a Radio Frequency Identification (RFID) component having a defined surface area, the defined surface area of the EAS component configured to at least partially overlap the defined surface area of the RFID component, an

Wherein the RFID component includes an antenna and an Application Specific Integrated Circuit (ASIC),

the method is characterized in that:

the ASIC has a complex impedance and the complex impedance of the ASIC matches a coupled complex conjugate impedance of the antenna including the load effects of the EAS component, an

The antenna includes a segment point at which the antenna can be cut at a slot to adjust the antenna length.

2. The security tag of claim 1, wherein the RFID component comprises an antenna; and

wherein the antenna at least partially overlaps the defined surface area of the EAS component.

3. The security tag of claim 1 wherein the substantially planar spacer having a thickness is at least partially located between the defined surface areas of the EAS component and the RFID component.

4. The security tag of claim 2, wherein the antenna has a complex impedance and the EAS component forms part of an impedance matching network of the antenna.

5. The security tag of claim 4 wherein said antenna impedance comprises a loading effect of an EAS component.

6. The security tag of claim 1, wherein the RFID component comprises a base portion, and wherein the material of the base portion is selected from the group consisting of: (a) base paper; (b) polyethylene; (c) a polyester; (d) polyethylene terephthalate PET; and (e) polyetherimide PEI.

7. The security tag according to claim 1, wherein the RFID component comprises a base portion, and wherein the material of the base portion is a plastic having a dielectric constant of about 3.3 and a loss tangent of less than about 0.01.

8. The security tag according to claim 3, wherein the material of the spacer is selected from the group consisting of: (a) low loss, low dielectric materials; and (b) air.

9. A method of operating a combination Electronic Article Surveillance (EAS) component and Radio Frequency Identification (RFID) component, the method comprising the steps of:

moving the RFID component to overlap the EAS component to change the impedance of an antenna coupled to the RFID component,

the method is characterized in that:

the complex impedance of the antenna including the load contribution of the EAS component is substantially equal to the complex conjugate impedance of the application specific integrated circuit ASIC contained in the RFID component,

wherein the antenna comprises an antenna conductor, and the antenna is tuned by:

cutting the antenna conductor into at least two sections such that at least one section corresponds to an antenna operating frequency based on the lengths of at least two antenna sections; and

the cut antenna conductor is isolated from the remainder of the conductor.