This application claims priority of Chinese Application No. 201010274841.3, filed on Sep. 6, 2010.
1. Field of the Invention
The present invention relates to an antenna system and an electronic apparatus having the same, more particularly to a multi-loop antenna system and an electronic apparatus having the same.
2. Description of the Related Art
Conventionally, planar inverted-F antennas are used in wireless devices, such as wireless access points. Taiwanese Patent No. M377714 discloses a monopole antenna system, which includes three monopole antennas that are formed on a grounding plane by cutting or punching techniques, and which is applicable to multiple-input-multiple-output wireless communications.
Although such an antenna system may be disposed in a housing of an electronic apparatus, the antenna system, however, has a three-dimensional structure and hence occupies a larger space, which consequently reduces space in the housing available for disposing of other electronic components. Furthermore, such an antenna system generally has gain values ranging from 3 dBi to 5 dBi in the 2.4 GHz and 5 GHz frequency bands, and radiation patterns thereof generally show lower directivity.
Therefore, an object of the present invention is to provide a multi-loop antenna system capable of alleviating the aforesaid drawbacks of the antenna system of the prior art.
Accordingly, a multi-loop antenna system of the present invention includes an antenna module and a system module. The antenna module includes a substrate, and a plurality of loop antennas. The loop antennas are disposed on the substrate, and are arranged such that each of extending lines extending respectively from geometric centers of the loop antennas to a center point that is bounded by the loop antennas has a predetermined length, and that each of the loop antennas is spaced apart from an adjacent one of the loop antennas by a predetermined minimum distance. Each of the loop antennas includes: a first radiator portion operable in a first frequency band, and having opposite ends that respectively serve as a signal-feed section and a grounding section, and that are adjacent to and spaced apart from each other such that the first radiator portion substantially forms a loop; and a second radiator portion operable in a second frequency band, and having opposite ends that are connected electrically and respectively to the signal-feed section and the grounding section of the first radiator portion, such that the second radiator portion substantially forms a loop. The system module has a grounding plane that faces toward and that is spaced apart from and parallel to the substrate such that the grounding plane is able to reflect radiation from the antenna module so as to enhance gain and directivity thereof.
Another object of the present invention is to provide an electronic apparatus having an antenna module and a system module.
Accordingly, an electronic apparatus of the present invention includes a housing, and an antenna module and a system module disposed in the housing. The antenna module includes a substrate, and a plurality of loop antennas. The loop antennas are disposed on the substrate, and are arranged such that each of extending lines extending respectively from geometric centers of the loop antennas to a center point that is bounded by the loop antennas has a predetermined length, and that each of the loop antennas is spaced apart from an adjacent one of the loop antennas by a predetermined distance. Each of the loop antennas includes: a first radiator portion operable in a first frequency band, and having opposite ends that respectively serve as a signal-feed section and a grounding section, and that are adjacent to and spaced apart from each other such that the first radiator portion substantially forms a loop; and a second radiator portion operable in a second frequency band, and having opposite ends that are connected electrically and respectively to the signal-feed section and the grounding section of the first radiator portion, such that the second radiator portion substantially forms a loop. The system module has a grounding plane that faces toward and that is spaced apart from and parallel to the substrate such that the grounding plane is able to reflect radiation from the antenna module so as to enhance gain and directivity of the multi-loop antenna system.
Other features and advantages of the present invention will become apparent in the following detailed description of the preferred embodiments with reference to the accompanying drawings, of which:
Before the present invention is described in greater detail, it should be noted that like elements are denoted by the same reference numerals throughout the disclosure.
Referring to
Referring to
The first radiator portion 3 of each of the loop antennas 2 is operable in a first frequency band preferably ranging from 2400 MHz to 2484 MHz, and has opposite ends that respectively serve as a signal-feed section 31 and a grounding section 32, and that are adjacent to and spaced apart from each other such that the first radiator portion 3 substantially forms a circular loop. The second radiator portion 4 of each of the loop antennas 2 is operable in a second frequency band preferably ranging from 5150 MHz to 5825 MHz, and has opposite ends 41, 42 that are connected electrically and respectively to the signal-feed section 31 and the grounding section 32 of the first radiator portion 3 of the loop antenna 2, such that the second radiator portion 4 substantially forms a circular loop.
In this embodiment, the second radiator portion 4 has a substantially circular loop-shaped radiator section 40 having opposite ends, and a pair of parallel extending sections 410, 420 extending from the opposite ends of the radiator section 40 and serving as the opposite ends 41, 42 of the second radiator portion 4, respectively. The pair of extending sections 410, 420 and the radiator section 40 cooperate to define a slot 430.
Referring to
It is worth noting that, in this embodiment, the through-hole 13 corresponds in position to the center point “A”, and the cables 5 are connected electrically and respectively to the loop antennas 2 via the through-hole 13 so as to avoid overlapping of the loop antennas 2 by the cables 5, thereby reducing interference between the cables 5 and the loop antennas 2.
In this embodiment, for each of the loop antennas 2, the first radiator portion 3 substantially encloses the second radiator portion 4. Such a configuration of the second radiator portion 4 with respect to the first radiator portion 3 ensures efficient usage of space. Specifically, the geometric center of each of the loop antennas 2 is bounded by the first radiator portion 3 instead of the second radiator portion 4 of the loop antenna 2. In this embodiment, for each of the loop antennas 2, the slot 430 opens in a direction that forms a predetermined included angle “a” with the respective one of the extending lines, and the first and second radiator portions 3, 4 are respectively symmetrical in the direction in which the slot 430 opens. The predetermined included angle “a” is preferably 45 degrees such that signals radiated by each of the loop antennas 2 are characterized by bipolar propagation in a direction perpendicular to the first surface 11 of the substrate 1.
However, referring to
In this embodiment, the system module 20 is a system circuit board having a grounding plane 201 that faces toward and that is spaced apart from and parallel to the second surface 12 of the substrate 1 such that the grounding plane 201 is able to reflect radiation from the antenna module 10. Radiation patterns of the multi-loop antenna system 100 thus exhibit high directivity and gain. Moreover, the system module 20 preferably has a multi-layer structure, of which the top layer is a thin metal layer serving as the grounding plane 201, and each of remaining layers is independently one of a substrate layer and a circuit layer. It is to be noted that, in other embodiments, the antenna module 10 and the system module 20 may be spaced apart from each other by a distance not smaller than 5 mm (e.g., 8.4 mm) so as to enable disposing of various electronic components therebetween. Furthermore, the substrate 1 occupies an area not larger than that occupied by the system module 20 such that the system module 20 is able to substantially reflect signals radiated by the antenna module 10.
Referring to
Each of the cables 5 is preferably a mini-coaxial cable connected electrically to the feed-in segment 31 of the respective loop antenna 2 for transmission and reception of signals therethrough.
In summary, the multi-loop antenna system 100 is applicable to multiple-input-multiple-output communications, is operable in the wireless local area network frequency bands, radiates signals with high directivity, and is characterized by relatively high isolation. In addition, because printed circuit board techniques are used to form the loop antennas 2, fabrication is relatively easy and costs less, and the multi-loop antenna system 100 has a low-profile of planar configuration suitable for application to small outdoor wireless devices.
While the present invention has been described in connection with what are considered the most practical and preferred embodiments, it is understood that this invention is not limited to the disclosed embodiments but is intended to cover various arrangements included within the spirit and scope of the broadest interpretation so as to encompass all such modifications and equivalent arrangements.
Number | Date | Country | Kind |
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201010274841.3 | Sep 2010 | CN | national |