Abstract:
A supplemental antenna assembly is provided for use with an electronic device having an integral radio antenna, such as a wireless-enabled laptop computer, notebook computer, gaming device, personal digital assistant (PDA), or circuit card (e.g., a PCMCIA card) or other circuit assembly designed be used with such a device. The supplemental antenna assembly includes a parasitic element supported by a frame. The frame is configured to be attached to the housing of the portable device such that an inductive coupling is provided between the parasitic element and the integral radio antenna. The parasitic element may include, for example, an antenna and/or a coupling element, e.g., a coupling element configured to be connected to an external antenna.

Description:
BACKGROUND OF THE INVENTION 
   The present invention relates to radio communications apparatus, and more particularly, to radio antenna apparatus. 
   Computing devices, such as laptop computers, notebook computers, pocket PCs, personal digital assistants (PDAs), gaming devices, and the like, now commonly possess wireless communications capabilities. For example, many laptop and notebook computers now incorporate radio communications circuitry configured to communicate with, for example, WiFi networks and/or public cellular networks. Such circuitry may be integrated in the computer and/or may be provided in a circuit assembly, such as a PC card or a USB adapter, which is plugged into the computer. Similar cards and/or adapters may be used with other electronic devices, such as PDAs and computer peripherals (e.g., printers, scanners, and the like) 
   Such wireless communications circuitry may be configured to connect to an external radio antenna and/or may include an integrated radio antenna. Some PC cards, for example, include an external antenna jack to which a rigid antenna and/or an antenna cable may be attached. A number of PC cards are also available which include an internal antenna without an external antenna connection. For example, referring to  FIG. 1 , a GC-79 GPRS/WiFi PCMCIA card  100  marketed by SonyEricsson Mobile Conununications, Inc., includes an internal antenna that is positioned within a housing  110  proximate an end of the card  100 . Many WiFi cards have a similar internal antenna configuration. 
   Constraints on the size and positioning of such internal antennas may cause antenna performance to be significantly degraded. For example, as shown in  FIG. 2 , when a wireless PC card  100  is mounted in a notebook computer  10 , the antenna  120  of the card  100  may be blocked or shadowed by the LCD screen of the computer  10 . This blockage or shadowing can result in a reduction of gain in certain directions. In addition, when the computer  10  is in a normal operating position, the polarization of the antenna  120  may be dominant in a horizontal plane. However, in certain fringe areas of low signal coverage, signal polarization may be dominantly vertical. The resulting polarization mismatch may lead to significant performance degradation. 
   SUMMARY OF THE INVENTION 
   In some embodiments of the present invention, a supplemental antenna assembly is provided for use with an electronic device having an integral radio antenna, such as a wireless-enabled laptop computer, notebook computer, gaming device, personal digital assistant (PDA), or circuit card, adaptor or other circuit assembly designed be used with such a device. The supplemental antenna assembly includes a parasitic element supported by a frame. The frame is configured to be attached to the housing of the portable device such that an inductive coupling is provided between the parasitic element and the integral radio antenna. The parasitic element may include, for example, an antenna and/or a coupling element, such as a coupling element configured to be connected to an external antenna. In some embodiments, the electronic device may preferentially radiate and/or receive radio signals over a frequency range in the absence of the supplemental antenna assembly, and the supplemental antenna assembly may increase radiation and/or reception in the frequency range. In other embodiments, the supplemental antenna assembly may increase radiation and/or reception at a frequency outside of the frequency range such that, for example, the electronic device supports an alternate second radio application. 
   In further embodiments of the present invention, the electronic device comprises a wireless communications circuit assembly configured to be installed in a computing device. For example, the wireless communications circuit assembly may be a circuit card, e.g., a PCMCIA or other computer card, having a radio antenna positioned proximate an end of the circuit card that extends from the computing device when installed therein. The frame may be configured to be attached to the circuit card proximate the end thereof. For example, the frame may be configured to envelope at least a portion of the circuit card including the integral radio antenna and/or to be retained in a retaining structure on the circuit card. 
   In further embodiments of the present invention, a supplemental antenna assembly for use with a wireless communications card having an internal radio antenna includes a parasitic element and a frame that supports the parasitic element. The frame is configured to be attached to the wireless communications card proximate the internal radio antenna such that an inductive coupling is provided between the internal radio antenna and the parasitic element. The wireless communications card may comprise a wireless communications PCMCIA card and the frame may be configured to be attached to the PCMCIA card proximate the end of thereof, such that an inductive coupling may be provided between the internal radio antenna and the parasitic element. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
       FIG. 1  illustrates a conventional PCMCIA wireless communications card. 
       FIG. 2  illustrates the conventional PCMCIA wireless communications card installed in a notebook computer. 
       FIGS. 3-11  illustrate supplemental antenna assemblies according to various exemplary embodiments of the present invention. 
   

   DETAILED DESCRIPTION OF EXEMPLARY EMBODIMENTS 
   Specific exemplary embodiments of the invention now will be described with reference to the accompanying drawings. This invention may, however, be embodied in many different forms and should not be construed as limited to the embodiments set forth herein; rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the invention to those skilled in the art. The terminology used in the detailed description of the particular exemplary embodiments illustrated in the accompanying drawings is not intended to be limiting of the invention. In the drawings, like numbers refer to like elements. 
   As used herein, the singular forms “a”, “an” and “the” are intended to include the plural forms as well, unless expressly stated otherwise. It will be further understood that the terms “includes,” “comprises,” “including” and/or “comprising,” when used in this specification, specify the presence of stated features, integers, steps, operations, elements, and/or components, but do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and/or groups thereof. It will be understood that when an element is referred to as being “connected” or “coupled” to another element, it can be directly connected or coupled to the other element or intervening elements may be present. Furthermore, “connected” or “coupled” as used herein may include wirelessly connected or coupled. As used herein, the term “and/or” includes any and all combinations of one or more of the associated listed items. 
   Unless otherwise defined, all terms (including technical and scientific terms) used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. It will be further understood that terms, such as those defined in commonly used dictionaries, should be interpreted as having a meaning that is consistent with their meaning in the context of the relevant art and will not be interpreted in an idealized or overly formal sense unless expressly so defined herein. 
     FIG. 3  is a schematic illustration of a supplemental antenna assembly  300  according to some embodiments of the present invention. The assembly  100  includes a parasitic element  320  and a supporting frame  310  configured to attach to a housing  110  of an electronic device  100  including an integral antenna  120 . In particular, in the illustrated example, the electronic device  100  comprises a PCMCIA card configured to be installed in a computer  10 , and the antenna  120  comprises a serpentine conductor positioned near the end of the card  100 . The frame  310  is shown in the form of a substrate, and the parasitic element  320  comprises a serpentine conductor which is supported by the substrate and vertically oriented to provide a dominant vertical polarization, i.e., substantially orthogonal to the substantially horizontal polarization of the integral antenna  120 . It will be appreciated, however, that the present invention is applicable to other electronic devices and/or other antenna configurations. 
     FIGS. 4 and 5  illustrate a supplemental antenna assembly  400  according to further embodiments of the present invention. The assembly  400  includes a frame or housing  410  that is configured to envelope an end  110  of a PCMCIA circuit card  100  that encloses an integral radio antenna  120 . The assembly  400  further includes an antenna, here shown as a vertically oriented stub antenna  430 , which is parasitically coupled to the integral antenna  120  when the assembly  400  is installed on the card  100 . In particular, as shown in  FIG. 5 , the assembly  400  includes a coupling element  420 , positioned in the housing  410 , that is configured to inductively (parasitically) couple to the integral antenna  120  of the card when the assembly  400  is installed on the card  100 . The coupling element  420  is conductively coupled to the antenna  430 . The housing  410  may be configured to snap onto or otherwise engage the end  110  of the circuit card  100  to retain the assembly  400  thereon. 
     FIGS. 6 and 7  illustrate a supplemental antenna assembly  600  with an alternative configuration according to further embodiments of the present invention. The assembly  600  includes a housing  610  that is configured to slip into slots  130  positioned proximate an end  110 ′ of a PCMCIA circuit card  100 ′ that houses an integral antenna  120 ′. The housing  610  supports an antenna  630  that is inductively coupled to the antenna  120 ′. In particular, the assembly  600  includes a coupling element  620 , positioned in the housing  610 , that is configured to inductively couple to the antenna  120 ′ when the assembly is installed on the card  100 ′, and which is conductively coupled to the antenna  630 . 
   It will be appreciated that, in various embodiments of the present invention, a supplemental antenna assembly may be attached to the housing of an electronic device in ways other than those illustrated in  FIGS. 4-7 . For example, a supplemental antenna assembly could be configured to be removably attached to a circuit card or other form factor device using, for example, Velcro®, clips, tabs, screws, threads, or other attachment means. 
     FIG. 8  illustrates a supplemental antenna assembly  800  for use with a circuit card  100 ″ having an internal antenna  120 ″ with a different orientation than the internal antennas shown in  FIGS. 4-7 . The assembly  800  includes a housing  810  that is configured to envelope an end of the circuit card  100 ″ proximate the antenna  120 ″. The housing  810  supports a coupling element  720  in a position such that it may be parasitically coupled to the antenna  120 ″ when the assembly  800  is in place. The coupling element  720  is conductively coupled to an antenna  830 . 
   According to further aspects of the present invention, a supplemental antenna apparatus for use with an electronic device having an integral antenna may include a parasitic coupling element that is configured to be removably connected to a rigid external antenna, such as a stub antenna, and/or to an antenna cable that may be attached to a freestanding antenna. For example, as shown in  FIG. 9 , a supplemental antenna assembly  900  according to further embodiments of the present invention includes a housing  910  configured to envelop an end of a circuit card  100  that houses an internal antenna  120 . The assembly  900  further comprises a parasitic coupling element  920  that is configured to be inductively coupled to the antenna  120  when the assembly  900  is installed. The coupling element  920  is conductively coupled to an external antenna connector  930 . In various embodiments, a rigid antenna and/or an antenna cable may be connected to the connector  930 . 
   It will be appreciated that the present invention is applicable to other types of electronic devices than PCMCIA circuit cards. For example,  FIGS. 10 and 11  illustrate supplemental antenna assemblies  1000 ,  1000 ′ configured for use with a wireless communications card  30  inserted in a PDA  20 . Referring to  FIG. 10 , the assembly  1000  includes a housing  1010  that envelopes the circuit card  30  and that supports a parasitically coupled antenna  1030 . Such an assembly may be used, for example, when the PDA  20  is being used in a high-blockage environment, such as in an automobile. Referring to  FIG. 11 , the assembly  1000 ′ includes a housing  1010 ′ that includes a parasitic coupling element (not shown) that is connected to an external connector  1020 . A freestanding antenna  40  is connected to the connector  1020  by a cable  50 . Such a configuration may be useful, for example, when the PDA  20  is mounted in a fixed position, e.g., inside a vehicle or a building. 
   Other applications of supplemental parasitic antenna assemblies fall within the scope of the present invention. For example, in some embodiments of the present invention, supplemental parasitic antenna assemblies may be configured to couple to integral radio antennas mounted in the case of a computer or other electronic device, rather than in a removable circuit card or other circuit assembly. In further embodiments, supplemental parasitic antennas may be configured for use with other radio devices, such as messaging devices, gaming devices, radiotelephones (e.g., handsets) and/or GPS receivers. 
   Performance of an electronic device may be improved using a supplemental parasitic antenna assembly according to various embodiments of the present invention. For example, improvements in radiation/reception characteristics, such as voltage standing wave ratio (VSWR), gain, and/or directivity, may be achieved using such a supplemental antenna assembly. Such a supplemental antenna assembly may also be used to provide additional or enhanced operational modes. For example, addition of a supplemental parasitic antenna may modify an internal antenna&#39;s existing pattern, such that reception and/or radiation is improved in a frequency range that is relatively attenuated when the parasitic element is absent. Thus, for example, if an integral antenna of an electronic device is configured to support a given radio application, addition of a parasitic element according to some embodiments of the present invention could support an additional or alternative radio application. 
   In the drawings and specification, there have been disclosed exemplary embodiments of the invention. Although specific terms are employed, they are used in-a generic and descriptive sense only and not for purposes of limitation, the scope of the invention being defined by the following claims.