1. Field of the Invention
The present invention relates to an antenna structure, and more particularly, to an antenna structure making use of a short element and a feeding element, which are independent and located on different planes, to generate two individual currents with the same direction, such that radiation patterns and antenna efficiency of the antenna structure can be improved.
2. Description of the Prior Art
As wireless telecommunication develops with the trend of micro-sized mobile communication products, the location and the space arranged for antennas are limited. Therefore, some built-in micro antennas have been developed. Currently, micro antennas such as chip antennas, planar antennas etc are commonly used. All these antennas have the feature of small volume. The planar antenna has the advantages of small size, light weight, ease of manufacturing, low cost, high reliability, and can also be attached to the surface of any object. Therefore, micro-strip antennas and printed antennas are widely used in wireless communication systems.
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Hence, how to improve antenna efficiency, adjust impedance matching, improve radiation patterns, and increase bandwidths of the antennas become important topics in this field.
It is one of the objectives of the present invention to provide an antenna structure to solve the abovementioned problems.
According to an aspect of the present invention, an antenna structure is provided. The antenna structure includes a radiation element, a grounding element, a short element, and a feeding element. The radiation element includes a first radiator and a second radiator, wherein the second radiator is extended from the first radiator and coupled to the first radiator. The short element includes a first end as well as a second end, wherein the first end of the short element is coupled to a joint in between the first radiator and the second radiator, and the second end of the short element is coupled to the grounding element. The feeding element includes a first end and a second end, and the first end of the feeding element is electrically connected with the radiation element. The short element is located on a first plane, and the feeding element is located on a second plane being different from the first plane.
According to another aspect of the present invention, an antenna structure is provided. The antenna structure includes a substrate, a radiation element, a grounding element, a short element, and a feeding element. The substrate has a first plane and a second plane opposite to the first plane. The radiation element is located on the first plane and includes a first radiator as well as a second radiator. The first radiator is used for resonating at a first operating frequency band corresponding to a first resonance mode. The second radiator is used for resonating at a second operating frequency band corresponding to a second resonance mode, wherein a first end of the second radiator is extended from a first end of the first radiator. The grounding element includes a first grounding sub-element located on the first plane as well as a second grounding sub-element located on the second plane. The short element is located on the first plane, wherein the short element is coupled between the first end of the first radiator and the first grounding sub-element. The feeding element is located on the second plane and electrically connected with the radiation element.
According to another aspect of the present invention, an antenna structure is provided. The antenna structure includes a substrate, a radiation element, a grounding element, a short element, and a feeding element. The substrate has a first plane and a second plane opposite to the first plane. The shot element is located on the first plane, wherein the short element includes at least a first segment and a second segment, the first segment as well as the second segment form a bend, the first segment is coupled to the radiation element, and the second segment is coupled to the grounding element. The feeding element is located on the second plane and electrically connected with the radiation element. A first current flowing through the first segment of the short element has the same direction as a second current flowing through the feeding element.
According to another aspect of the present invention, an antenna structure is provided. The antenna structure includes a grounding element, a radiation element, a short element, and a feeding element. The radiation element includes a first radiator as well as a second radiator, wherein the second radiator is extended from the first radiator and coupled to the first radiator. The short element is coupled between a joint in between the first radiator as well as the second radiator and the grounding element. The feeding element is electrically connected with the radiation element. The radiation element and the short element are located on a first plane, the feeding element is located on a second plane being different from the first plane, and the grounding element is located on a third plane being different from the first plane and the second plane.
According to another aspect of the present invention, an antenna structure is provided. The antenna structure includes a grounding element, a short element, a radiation element, and a feeding element. The radiation element includes a first radiator as well as a second radiator, wherein the second radiator is extended from the first radiator and coupled to the first radiator. A first current flowing through the short element has the same direction as a second current flowing through the feeding element. The grounding element, the short element, the radiation element, and the feeding element belong to different parts of an identical metal sheet, respectively. The grounding element, the short element, the radiation element, and the feeding element are sequentially surrounded and disposed so as to form a hollow space.
These and other objectives of the present invention will no doubt become obvious to those of ordinary skill in the art after reading the following detailed description of the preferred embodiment that is illustrated in the various figures and drawings.
Be noted that in the embodiments thereinafter, the same components or similar components are denoted by using the same symbols or similar symbols in order to facilitate the description, and there is no need to give unnecessary details for the same description. The present invention is focused on improving the conventional PIFA, which makes uses of a short element and a feeding element located on different planes to generate two individual currents with the same direction in order to solve the abovementioned problems in the prior art.
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As shown in 3A, the radiation element 230, the short element 250, and the first grounding sub-element 242 of the antenna structure 200 are located on the first plane 290A. The radiation element 230 has a first radiator 210 and a second radiator 220, wherein a first end 221 of the second radiator 220 is extended from a first end 211 of the first radiator 210. Be noted that the first radiator 210 resonates at a first operating frequency band corresponding to a first resonance mode (e.g., GSM-1800/1900 or WCDMA-2100), and the second radiator 220 resonates at a second operating frequency band corresponding to a second resonance mode (e.g., GSM-850/900). In addition, the short element 250 has a first end 251 and a second end 252, wherein the first end 251 is coupled to the joint in between the first radiator 210 and the second radiator 220, and the second end 252 is coupled to the first grounding sub-element 242.
As shown in 3B, the feeding element 260 and the second grounding sub-element 244 of the antenna structure 200 are located on the second plane 290B. The feeding element 260 has a first end 261 and a second end 262. Moreover, a feeding signal source 270 is disposed between the feeding element 260 and the second grounding sub-element 244, for exciting the antenna structure 200. Herein a positive signal terminal of the feeding signal source 270 is coupled to the second end 262 of the feeding element 260, and then the feeding element 260 is electrically connected with the radiator element 230 located on the first plane 290A through the second via hole 282; while a negative signal terminal of the feeding signal source 270 is coupled to the second grounding sub-element 244.
Please note that since the first grounding sub-element 242 and the second grounding sub-element 244 are individually located on different planes, while the feeding element 260 and the radiation element 230 are individually located on different planes, extra conducting components are required in order to electronically connect them with each other. In this embodiment, the antenna structure 200 further includes a first via hole 281 and a second via hole 282. The first via hole 281 is disposed in between the first grounding sub-element 242 and the second grounding sub-element 244 and passes through the first plane 290A and the second plane 290B of the substrate 290, for electrically connecting the first grounding sub-element 242 with the second grounding sub-element 244. However, the number of the first via hole 281 is not limited, or there is no need to additionally dispose the first via hole 281 in between the first grounding sub-element 242 and the second grounding sub-element 244. Similarly, the second via hole 282 is disposed in between the feeding element 260 and the radiation element 230 and passes through the first plane 290A and the second plane 290B of the substrate 290, for electrically connecting the feeding element 260 with the radiation element 230. Be noted that the number of the second via hole 282 is not limited.
What calls for special attention is that the short element 250 is used for electronically connecting the radiation element 230 with the grounding element 240 in order to adjust impedance matching. As a result, the style of the short element 250 can be adjusted depending on actual designs, and can have an arbitrary shape. That is to say, the short element 250 may include a plurality of segments to form at least one bend, but the number of the segments and the number of the bends are not limited. As
Please also note that the feeding element 260 may have an arbitrary shape, and its style can be adjusted depending on actual designs. In this embodiment, the feeding element 260 is implemented by a rectangle which only has one segment, but this should not be considered as limitations of the present invention. In other embodiments, the feeding element 260 may include a plurality of segments. As an illustration, the feeding element 260 may have a left extension segment extended to its left direction and a right extension segment extended to its right direction, respectively. Herein the left extension segment and the right extension segment are respectively located on positions corresponding to the first radiator 210 and the second radiator 220, and the left extension segment and the right extension segment (partially or completely) overlap the first radiator 210 and the second radiator 220, respectively. Those skilled in the art should appreciate that various modifications of the feeding element 260 may be made without departing from the spirit of the present invention, which also belongs to the scope of the present invention.
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The antenna structure 200 shown in
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In the abovementioned embodiments, the short element 250 and the feeding element 260 or 660 are separately disposed on different positions of different planes, but the present invention is not limited to this only. In other embodiments, the short element 250 and the feeding element 260/660 can be disposed on the same position of different planes, which also belongs to the scope of the present invention. Please refer to
What calls for special attention is that the first end 761 of the feeding element 760 is at a designated distance X3 from the second end 212 of the first radiator 210 on a projection plane (i.e., the XY plane), and the first end 761 of the feeding element 760 is at a designated distance X4 from the second end 222 of the second radiator 220 on the projection plane (i.e., the XY plane). Herein the antenna structure 700 has a better antenna efficiency when the designated distance X3 is in between one-eighth and one-sixth of the first wavelength (i.e., λ⅛<X3<λ⅙) or the designated distance X4 is in between one-eighth and one-sixth of the second wavelength (i.e., λ 2/8<X4<λ 2/6).
As can be known from the abovementioned embodiments, the projection of the first end of the feeding element projected on the radiation element 230 is not limited. Those skilled in the art should appreciate that various modifications to the location of the feeding element may be made without departing from the spirit of the present invention.
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In other words, the bending direction of the short element in no way should be considered as limitations of the present invention. Those skilled in the art should appreciate that various modifications to the bending direction of the short element may be made without departing from the spirit of the present invention.
In the embodiments above, a printed circuit board (PCB) is adopted for designing the antenna structures 200˜900 (e.g., the substrate 290), but the present invention is not limited to this only. In other embodiments, other materials or other means can be adopted for designing the antenna structure disclosed in the present invention.
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As shown in 11A, the radiation element 1130 as well as the short element 1150 of the antenna structure 100 are located on the first plane 1190A. The radiation element 1130 includes a first radiator 1110 and a second radiator 1120, and a first end 1121 of the second radiator 1120 is extended from a first end 1111 of the first radiator 1110. Herein the first radiator 1110 is used for resonating at a first operating frequency band corresponding to a first resonance mode (e.g., GSM-1800/1900 or WCDMA-2100), and the second radiator 1120 is used for resonating at a second operating frequency band corresponding to a second resonance mode (e.g., GSM-850/900). In addition, the short element 1150 has a first end 1151 and a second end 1152, wherein the first end 1151 is coupled to the joint in between the first radiator 1110 and the second radiator 1120, and the second end 1152 is coupled to the grounding element 1140 (as is shown in
As shown in 11B, the feeding element 1160 of the antenna structure 1000 is located on the second plane 1190B. The feeding element 1160 has a first end 1161 and a second end 1162. Moreover, a feeding signal source 1170 is disposed between the feeding element 1160 and the grounding element 1140, for exciting the antenna structure 1000. Herein a positive signal terminal of the feeding signal source 1170 is coupled to the second end 1162 of the feeding element 1160, and then the feeding element 1160 is electrically connected with the radiator element 1130 located on the first plane 1190A through the second feeding element 1180 (as is shown in
Please note that since the feeding element 1160 and the radiation element 1130 are individually located on different planes, extra conducting components are required in order to electronically connect them with each other. In this embodiment, the antenna structure 1000 further includes a second feeding element 1180, for electrically connecting the feeding element 1160 with the radiator element 1130. Herein the second feeding element 1180 is located on a fourth plane 1190D, and the fourth plane 1190D is substantially parallel to the third plane 1190C, that is to say, it is perpendicular to the first plane 1190A as well as the second plane 1190B.
Please also note that in this embodiment, the radiation element 1130, the short element 1150, the grounding element 1140, the feeding element 1160, and the second feeding element 1180 are an all-in-one design, and they belong to different parts of an identical metal sheet. Furthermore, the grounding element 1140, the short element 1150, the radiation element 1130, the second feeding element 1180 and the feeding element 1160 are sequentially surrounded and disposed so as to form a hollow space.
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What calls for special attention is that the short element 1150 is used for electronically connecting the radiation element 1130 with the grounding element 1140 in order to adjust impedance matching of the antenna structure 1000. As a result, the style of the short element 1150 can be adjusted depending on actual designs, and may have an arbitrary shape. In addition, the bending direction of the short element 1150 in no way should be considered as limitations of the present invention. Those skilled in the art should appreciate that various modifications to the bending direction of the short element may be made without departing from the spirit of the present invention.
What's more, a projection of the first end 1161 of the feeding element 1160 projected on the radiation element 1130 is no limited. For example, it may be located on the first radiator 1110, on the second radiator 1120, or at the joint in between the first radiator 1110 and the second radiator 1120. Those skilled in the art should appreciate that various modifications to the X-axis coordinate of the feeding element 1160 may be made without departing from the spirit of the present invention.
The abovementioned embodiments are presented merely to illustrate practicable designs of the present invention, and in no way should be considered to be limitations of the scope of the present invention. Undoubtedly, those skilled in the art should appreciate that various modifications of the antenna structures 200˜1000 shown in
From the above descriptions, the present invention provides an antenna structure making use of a short element and a feeding element, which are independent and located on different planes, to generate two individual currents with the same direction. Therefore, no matter the antenna structure is operated under the low frequency or high frequency, synergistic effects can be produced in the radiation patterns of the antenna structure. As a result, antenna efficiency can be further improved, and the antenna bandwidth of the antenna structure can be increased.
Those skilled in the art will readily observe that numerous modifications and alterations of the device and method may be made while retaining the teachings of the invention.
Number | Date | Country | Kind |
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099200248 | Jan 2010 | TW | national |