This document pertains generally, but not by way of limitation, to a surface mount assembly including an antenna.
Information can be wirelessly transferred using electromagnetic waves. Generally, such electromagnetic waves are either transmitted or received using a specified range of frequencies, such as established by a spectrum allocation authority for a location where a particular wireless device or assembly will be used or manufactured. Such wireless devices or assemblies generally include one or more antennas, and such antennas can be configured for transfer of information at a particular range of frequencies. Frequencies used for such communication can include frequencies used by various wireless digital data networking schemes. Wireless networking schemes can use, or incorporate aspects of one or more of the IEEE 802.11 family of “Wi-Fi” standards, one or more of the IEEE 802.16 family of “WiMax” standards, one or more of the IEEE 802.15 family of personal area network (PAN) standards, or one or more other protocols or standards, such as for providing cellular telephone or data services, fixed or mobile terrestrial radio, satellite communications, or for other applications. For example, in the United States, various ranges of frequencies are allocated for low-power industrial, scientific, or medical use (e.g., an “ISM” band allocation), such as including a first ISM band in the range of about 902 MHz to 928 MHz, or including a second ISM band in the range of about 2400 MHz to about 2483.5 MHz, or including a third ISM band in the range of about 5725 MHz to about 5825 MHz, among other ranges of frequencies.
In a system, a wireless communication circuit can be coupled to a separate antenna assembly, such as to provide reliable communications coverage within a building, around a site, or over a larger area, using a specified range of frequencies.
The present inventor has recognized, among other things, that integrating wireless communication circuitry or an antenna into an electronic system can pose various challenges. Use of a separate antenna assembly can be cumbersome, such as involving specialized radio-frequency (RF) connectors, cabling, or other techniques. Also, placing communication circuitry in proximity to other non-wireless circuitry can involve challenges such as grounding, shielding, or isolating the non-wireless circuitry and the communication circuitry from each other.
To reduce such design challenges, the present inventor has also recognized that a wireless communication circuit and an antenna can be integrated into a commonly-shared printed circuit board (PCB) assembly, such as including an antenna structure formed in one or more conductive layers comprising the PCB assembly. Incorporation of both the antenna and the wireless communication circuit into the same compact PCB can mitigate some of the design challenges associated with the layout and placement of wireless communication circuitry, or the challenges of designing or specifying an antenna for use with such circuitry. Such an assembly can include one or more surface mount interconnects, such as one or more pads, solder balls, metallic land regions, or other conductive portions configured to provide a solderable connection or other conductive bond to circuitry located on another printed circuit board assembly. In this manner, the PCB assembly including the circuitry and antenna can be easily incorporated into other designs in much the same way as other off-the-shelf components.
In an example, the present inventor has developed techniques to provide an embedded antenna structure including a usable bandwidth well in excess of the bandwidth generally needed for an IEEE 802.15.4 (2003) PHY layer (e.g., 16 channels times 5 MHz of bandwidth per channel, corresponding to 80 MHz of bandwidth, such as including a frequency range from about 2402.5 MHz to about 2477.5 MHz). Such excess bandwidth can provide an antenna structure that is more immune to variation in material parameters or the surrounding environment while still providing a specified input impedance within a specified range of operating frequencies, as compared to a narrow-band antenna.
According to various examples, an apparatus, system, or method can include a dielectric sheet and an antenna structure. The antenna structure includes a first conductive portion located on an exterior surface of the dielectric sheet and configured for coupling to an antenna feed for a wireless communication circuit, and a second conductive portion buried in the dielectric sheet and configured for coupling to a return portion of the wireless communication circuit. The second conductive portion includes a plane area adjacent to the first conductive portion in a region proximal to the feed portion and separated from the first conductive portion by a portion of the dielectric sheet, a curved transition portion, the transition portion including a lateral width that tapers along the length of the second conductive portion, a distal portion comprising two parallel conductive strips, the distal portion electrically coupled to the plane area via the curved transition portion, wherein the parallel conductive strips are thinner in lateral width than the plane area.
This overview is intended to provide an overview of subject matter of the present patent application. It is not intended to provide an exclusive or exhaustive explanation of the invention. The detailed description is included to provide further information about the present patent application.
In the drawings, which are not necessarily drawn to scale, like numerals may describe similar components in different views. Like numerals having different letter suffixes may represent different instances of similar components. The drawings illustrate generally, by way of example, but not by way of limitation, various embodiments discussed in the present document.
The first or second conductive layers 304A-B can include a metal foil, such as adhered or attached to one or more of the dielectric layers 306A-B. Such a metal foil can include copper, aluminum, tungsten, platinum, gold, nickel, or one or more other conductive materials, such as in a foil or film configuration. Such a metal layer can be patterned or etched, such as using a lithographic processing technique, such as to provide electrical interconnections between circuitry included as a portion of the assembly 310. In an example, one or more portions of the antenna structure of
In order to avoid reflections or to efficiently transfer power from the wireless communication circuit to the antenna structure, a conjugate impedance match is desired at the feed and return portions of the wireless communication circuit (e.g., at the antenna “port” of the communication circuit). The second conductive portion 404B can include a transition portion. Such a transition portion can encourage radiation, but without presenting an undesired impedance discontinuity. Such a discontinuity can cause unwanted reflections, or can decrease the usable bandwidth of the antenna structure. A curved transition portion 416 can provide both a tapered lateral width, along with a bend in the path of the second conductive portion 404B. Such a bend, transitioning from a first cross-sectional axis 422 to an orthogonal second cross-sectional axis 424, provides an antenna structure that efficiently uses the available surface area of the dielectric sheet 406. Such a bend can also enhance polarization diversity or can provide a more omnidirectional radiation pattern, such as shown in the radiation pattern of
The second conductive portion 404B can include a distal portion, such as including a capacitive coupling portion 420 (e.g., between the second axis 424 and a third axis 426), and two or more parallel conductive strips such as a first strip 414A and a second strip 414B. The capacitive coupling portion 420 can be located adjacent to a similarly-shaped region along the first conductive portion 404A, such as separated by a portion of the dielectric sheet 406. The capacitive coupling portion 420 can be used to provide a tunable capacitive contribution to the input impedance of the antenna structure, or to adjust an electrical length of the antenna structure. The usable bandwidth of the antenna structure can be adjusted, such as via one or more of the first or second strips 414A-B. For example, the first or second strips 414A-B can be used to provide respective antenna resonant frequencies, such as controlled at least in part by a longitudinal length of the first or second strips 414A-B along the second conductive portion 404B. A variation in the length of first strip 414A as compared to the second strip 414B can be used to provide a broad range of usable frequencies, such as shown in the return loss simulated in the illustrative example of
The present inventor has also realized that both the first conductive portion of
In an example, a surface mount assembly such as shown in the example of
Such a return loss provides a considerably wider range of usable operating frequencies than is generally needed for an IEEE 802.15.4 (2003) PHY layer (e.g., 16 channels times 5 MHz of bandwidth per channel, corresponding to 80 MHz of bandwidth, such as including a frequency range from about 2402.5 MHz to about 2477.5 MHz), where the antenna input impedance is within a specified range (e.g., corresponding to the return loss of −10 dB or lower (more negative)). In this manner, the present inventor has recognized that such an antenna structure can be cost effective (e.g., existing printed circuit board assembly materials can be used eliminating the incremental cost of the antenna). Such an antenna can also be relatively insensitive to production variations in conductor or dielectric geometry, temperature, moisture content, conductivity, or surrounding use environment. For example, the center frequency of around 2.45 GHz would need to shift by approximately plus 150 MHz or minus 300 MHz to result in a return loss of greater than −10 dB. Such a shift is unlikely to occur within the expected range of production variations and usage environments.
The above detailed description includes references to the accompanying drawings, which form a part of the detailed description. The drawings show, by way of illustration, specific embodiments in which the invention can be practiced. These embodiments are also referred to herein as “examples.” Such examples can include elements in addition to those shown or described. However, the present inventor also contemplates examples in which only those elements shown or described are provided. Moreover, the present inventor also contemplates examples using any combination or permutation of those elements shown or described (or one or more aspects thereof), either with respect to a particular example (or one or more aspects thereof), or with respect to other examples (or one or more aspects thereof) shown or described herein.
All publications, patents, and patent documents referred to in this document are incorporated by reference herein in their entirety, as though individually incorporated by reference. In the event of inconsistent usages between this document and those documents so incorporated by reference, the usage in the incorporated reference(s) should be considered supplementary to that of this document; for irreconcilable inconsistencies, the usage in this document controls.
In this document, the terms “a” or “an” are used, as is common in patent documents, to include one or more than one, independent of any other instances or usages of “at least one” or “one or more.” In this document, the term “or” is used to refer to a nonexclusive or, such that “A or B” includes “A but not B,” “B but not A,” and “A and B,” unless otherwise indicated. In this document, the terms “including” and “in which” are used as the plain-English equivalents of the respective terms “comprising” and “wherein.” Also, in the following claims, the terms “including” and “comprising” are open-ended, that is, a system, device, article, or process that includes elements in addition to those listed after such a term in a claim are still deemed to fall within the scope of that claim. Moreover, in the following claims, the terms “first,” “second,” and “third,” etc. are used merely as labels, and are not intended to impose numerical requirements on their objects.
Method examples described herein can be machine or computer-implemented at least in part. Some examples can include a computer-readable medium or machine-readable medium encoded with instructions operable to configure an electronic device to perform methods as described in the above examples. An implementation of such methods can include code, such as microcode, assembly language code, a higher-level language code, or the like. Such code can include computer readable instructions for performing various methods. The code may form portions of computer program products. Further, in an example, the code can be tangibly stored on one or more volatile, non-transitory, or non-volatile tangible computer-readable media, such as during execution or at other times. Examples of these tangible computer-readable media can include, but are not limited to, hard disks, removable magnetic disks, removable optical disks (e.g., compact disks and digital video disks), magnetic cassettes, memory cards or sticks, random access memories (RAMs), read only memories (ROMs), and the like.
The above description is intended to be illustrative, and not restrictive. For example, the above-described examples (or one or more aspects thereof) may be used in combination with each other. Other embodiments can be used, such as by one of ordinary skill in the art upon reviewing the above description. The Abstract is provided to comply with 37 C.F.R. §1.72(b), to allow the reader to quickly ascertain the nature of the technical disclosure. It is submitted with the understanding that it will not be used to interpret or limit the scope or meaning of the claims. Also, in the above Detailed Description, various features may be grouped together to streamline the disclosure. This should not be interpreted as intending that an unclaimed disclosed feature is essential to any claim. Rather, inventive subject matter may lie in less than all features of a particular disclosed embodiment. Thus, the following claims are hereby incorporated into the Detailed Description, with each claim standing on its own as a separate embodiment, and it is contemplated that such embodiments can be combined with each other in various combinations or permutations. The scope of the invention should be determined with reference to the appended claims, along with the full scope of equivalents to which such claims are entitled.
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Number | Date | Country | |
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20120306700 A1 | Dec 2012 | US |