This application claims the benefit under 35 U.S.C. §119(a) of a Korean patent application filed in the Korean Intellectual Property Office on Aug. 17, 2010 and assigned Serial No. 10-2010-0079223, the entire disclosure of which is hereby incorporated by reference.
1. Field of the Invention
The present invention relates to a built-in antenna and a method for improving antenna efficiency. More particularly, the present invention relates to a built-in antenna and a method for improving antenna efficiency in order to improve an antenna radiation property, to prevent radiation deterioration caused by a metal construction used to improve an outer appearance of a terminal, and to ensure mechanical robustness.
2. Description of the Related Art
With rapid technological advancement, a wireless communication function has been included not only in a mobile communication device but also in a portable electronic device (e.g., a media reproducing device, an electronic dictionary, a tablet, and the like), and the portable electronic device including such a wireless communication function has been used in everyday life. Portable electronic device users now prefer a smaller device having various functions. To satisfy the customers' preference, manufacturers are making an effort to decrease a size of components used in the portable electronic device and to integrate several functions into one component.
Such a change may occur equally in an antenna used to transmit and receive a radio wave. As a frequency band required for various services may be implemented by using one antenna, an effort to decrease a size of the antenna is ongoing.
A built-in antenna used in the portable electronic device of the related art is produced such that a metal layer is patterned on a circuit board so as to be used as an antenna radiator, or such that a metal sheet is patterned on a dielectric structure that supports an antenna radiator.
A Planar Inverted F Antenna (PIFA) and a monopole antenna are used as a built-in antenna widely used in a portable electronic device. These antennas have a disadvantage in that a performance-to-size relation cannot be designed in a complementary manner. More particularly, when a metal construction and a metal component are located near an antenna, there is a problem in that the antenna's radiation efficiency is decreased and a band is also decreased.
The portable electronic device of the related art has a sufficient space for placing an antenna and a sufficient separation distance to a metal portion. In addition, it is not difficult to design an antenna for the portable electronic device of the related art since an exterior of the portable electronic device is formed with a dielectric material, such as plastic. However, as the portable electronic device gradually decreases in size and thickness, a space for placing the antenna is being decreased, and a distance to the surrounding metal construction and metal component is being narrowed.
The aforementioned metal structure not only contributes to improving mechanical robustness but also improves the appearance of the portable electronic device. Therefore, there is an ongoing effort for applying this structure to a part of the portable device, more particularly, to a frame of the portable terminal.
However, it is difficult for the aforementioned built-in antenna of the related art to satisfy such a requirement as a compact size, efficiency increase, and a wide band in such extreme surrounding conditions.
In order to address this problem, antenna efficiency is implemented by using the antenna of the related art in such a manner that an antenna pattern is deployed by being spaced apart from a metal construction by a maximum distance possible in a narrow space for placing the antenna or that the metal construction existing at a portion where the antenna is located is processed with insert molding, or that a thickness of the portion where the antenna is located is increased. However, if an antenna pattern is deployed far from a metal component and a metal construction, a space for placing the antenna becomes further decreased and thus it becomes difficult to ensure more space. In addition, a method of performing an insert molding process on an antenna part impairs an outer appearance of the antenna since there is a disparity between metal and insert molding processes in a design aspect even if it is easy to ensure radiation efficiency. Furthermore, although radiation efficiency may be ensured by using a method of increasing a thickness of the portable electronic device, this method cannot make the portable terminal slim, which is a current design trend.
When the aforementioned metal construction is deployed in a front surface of the portable terminal, it has been used by being connected to a main ground. Such a structure exhibits a typical radiation deterioration phenomenon. That is, if there is a metal structure extended from the ground in the front surface of the antenna, a near field induces current in a corresponding metal member and generates thermal loss and radiation loss together with lossy volume, thereby resulting in an overall radiation efficiency deterioration.
To address such problems, a method in which a metal portion of an antenna is processed with insert molding and the remaining portions of a front surface of the antenna are subjected to metal processing has been used. However, this method has a problem in that a disparity occurs between metal and insert molding processes in a design aspect. A method in which the entire front surface of the device is subjected to metal processing and a distance between an antenna and the front-surface metal member is increased to the maximum extent possible by increasing a thickness of the terminal has a problem in that a slimming trend in the designing of the terminal cannot be satisfied. A method in which a front-surface metal member of a terminal is separated from a main ground can utilize the front-surface metal as a radiator, but may cause an Electro-Static Discharge (ESD) problem or a problem of radiation efficiency deterioration due to user influence.
Therefore, a need exists for a built-in antenna implemented to have a wide bandwidth and a method for improving antenna efficiency.
Aspects of the present invention are to address at least the above-mentioned problems and/or disadvantages and to provide at least the advantages described below. Accordingly, an aspect of the present invention is to provide a built-in antenna implemented to have a wide bandwidth and an excellent radiation property even if a metal construction exists, and a method and an apparatus for improving antenna efficiency.
Another aspect of the present invention is to provide a built-in antenna implemented to make a terminal slim and robust by deploying a metal construction at a desired position while implementing excellent radiation efficiency of the antenna, and a method of improving antenna efficiency.
Another aspect of the present invention is to provide a built-in antenna implemented to prevent deterioration of a radiation property of an antenna by processing a metal construction and utilizing the metal construction as an antenna radiator, and a method of improving antenna efficiency.
In accordance with an aspect of the present invention, a built-in antenna of a portable terminal is provided. The built-in antenna includes a first conductor having a specific length and used for a ground, a second conductor disposed with a specific distance in parallel to the first conductor to couple with the first conductor and used for power feeding, and a separating element disposed between the first conductor and the second conductor to separate the first and second conductors.
The first conductor and the second conductor may have various cross-sectional shapes under a condition that the two conductors are disposed in parallel, and may also have various shapes in a lengthwise direction. Such a condition shall further improve a radiation property while minimizing an antenna radiator.
The aforementioned lengthwise coupling-type built-in antenna may prevent radiation property deterioration caused by a metal frame used as a part of the portable terminal. This is because the sufficient lengthwise coupling between the first conductor and the second conductor generates significantly great capacitance, and thus minimizes an influence of a surrounding metal.
An exemplary embodiment of the present invention provides a method of preventing a built-in antenna against radiation property deterioration caused by a metal construction used in a terminal.
In accordance with an aspect of the present invention, a method of forming a high efficiency antenna in a portable terminal is provided. The method includes forming a metal construction in a portion of the portable terminal, and forming a built-in antenna radiator inside the portable terminal around the metal construction, wherein at least one portion of the metal construction around the built-in antenna radiator is cut to have a slightly open structure so that the metal construction operates as an extended ground and an antenna radiator.
The open structure is preferably applied to a metal construction closest in distance to a feed portion of the antenna radiator.
Other aspects, advantages, and salient features of the invention will become apparent to those skilled in the art from the following detailed description, which, taken in conjunction with the annexed drawings, discloses exemplary embodiments of the invention.
The above and other aspects, features, and advantages of certain exemplary embodiments of the present invention will be more apparent from the following description taken in conjunction with the accompanying drawings, in which:
Throughout the drawings, like reference numerals will be understood to refer to like parts, components and structures.
The following description with reference to the accompanying drawings is provided to assist in a comprehensive understanding of exemplary embodiments of the invention as defined by the claims and their equivalents. It includes various specific details to assist in that understanding but these are to be regarded as merely exemplary. Accordingly, those of ordinary skill in the art will recognize that various changes and modifications of the embodiments described herein can be made without departing from the scope and spirit of the invention. In addition, descriptions of well-known functions and constructions may be omitted for clarity and conciseness.
The terms and words used in the following description and claims are not limited to the bibliographical meanings, but, are merely used by the inventor to enable a clear and consistent understanding of the invention. Accordingly, it should be apparent to those skilled in the art that the following description of exemplary embodiments of the present invention is provided for illustration purpose only and not for the purpose of limiting the invention as defined by the appended claims and their equivalents.
It is to be understood that the singular forms “a”, “an”, and “the” include plural referents unless the context clearly dictates otherwise. Thus, for example, reference to “a component surface” includes reference to one or more of such surfaces.
By the term “substantially” it is meant that the recited characteristic, parameter, or value need not be achieved exactly, but that deviations or variations, including for example, tolerances, measurement error, measurement accuracy limitations and other factors known to those of skill in the art, may occur in amounts that do not preclude the effect the characteristic was intended to provide.
Although a portable terminal illustrated in the following exemplary embodiments of the present invention is a bar-type terminal, exemplary embodiments of the present invention are not limited thereto. Exemplary embodiments of the present invention may be applied to various types of terminals, for example, a terminal in which a metal frame is formed partially or fully in the terminal to provide an attractive outer appearance or to reinforce robustness.
Referring to
The metal frame 110, which encompasses the body 101 of the portable terminal 100 and which is disposed fully or partially to the terminal, causes radiation property deterioration and decrease in efficiency in the built-in antenna. Thus, a built-in antenna having a specific lengthwise direction (i.e., a ‘rail antenna’ 10 of
Referring to
The inner conductor 13 and the outer conductor 11 are disposed in parallel in a lengthwise direction, and it is allowed to generate mutual coupling while avoiding physical contact. Therefore, a dielectric member 12 of
In addition, although it is illustrated that the built-in antenna 10 is inserted such that the inner conductor 13 is inserted inside the outer conductor 11 by being spaced apart by a specific distance, exemplary embodiments of the present invention are not limited thereto. The inner conductor 13 and the outer conductor 11 may be disposed in parallel in a lengthwise direction such that the two conductors are spaced apart from each other by a specific distance by means of the dielectric member or the magnetic member.
Referring to
In addition, one or more support members 143 and 144 may be installed in a protrusion manner on the main board 14 to support a built-in antenna 10. However, exemplary embodiments of the present invention are not limited thereto, and thus an inner conductor 13 or an outer conductor 11 may be fixed by performing bonding directly on the main board without having to use the support members 143 and 144.
The outer conductor 11 includes a ‘U’-shaped slot or slit 111, and is bent in a curved shape along a bending surface of the main board 14. The inner conductor 13 is disposed to the slit 111 of the outer conductor 11 in a lengthwise direction in a mounted manner. In this case, the inner conductor 13 and the outer conductor 11 do not physically contact with each other, and for this structure, a dielectric member (e.g., a resin) or a magnetic member or a hybrid-type block is disposed between the inner conductor 13 and the outer conductor 11. The dielectric member 12 or the magnetic member may be partially disposed in at least one portion between the inner conductor 13 and the outer conductor 11 in order to avoid thermal loss. The inner conductor 13 may be formed in various shapes, which may facilitate extension of a ground area. The dielectric member 12 or the magnetic member may be further disposed to encompass or support the conductor. In addition to the dielectric member and the magnetic member, various shapes, such as a hybrid block shape, may also be used. In addition, the inner conductor 13 and/or the outer conductor 11 may be installed in an insert molding manner to the dielectric material 12.
Therefore, the inner conductor 13 is electrically connected to the ground portion 141 of the main board 14 of the portable terminal 100, and the outer conductor 11 is electrically connected to the feed portion 142 of the main board 14 of the portable terminal 100. However, exemplary embodiments of the present invention are not limited thereto, and thus the outer conductor 11 may be electrically connected to the metal frame 110 to utilize the metal frame 110 as a ground member. If necessary, at least one portion of the outer metal 11 may be electrically connected to the feed portion 142, and at least one portion of the inner metal 13 may also be electrically connected to the ground portion 141. Alternatively, at least one portion of the outer metal and at least one portion of the inner metal may be connected to the feed portion or the ground portion, respectively.
Consequently, the antenna (or rail antenna) 10 may implement a built-in antenna radiator operating with a desired antenna radiation pattern and a relatively wide frequency band by minimizing an influence (i.e., by avoiding influence) of a surrounding metal portion (i.e., metal frame) due to very large capacitance between an oscillation metal portion and a coupling metal portion.
As illustrated, the inner metal 13 and the outer metal 11 are bent in a curved shape along a bending portion of the main board 14. However, exemplary embodiments of the present invention are not limited thereto, and thus they may be deployed in a linear shape if a desired antenna radiation pattern is sufficiently implemented.
Herein, the optimization process is a process in which a length, shape, or the like of inner and outer conductors is taken into account, a width, the number, or the like of dielectric members is determined, and an optimal radiation property of an optimal antenna radiator is regulated by using a matching circuit, or the like, in a contact line of a feed portion and/or a ground portion.
Referring to
Referring to
Referring to
Referring to
The built-in antenna 10 having a single band has been described above in an exemplary embodiment of the present invention. In
Referring to
Referring to
A feed pin 213 protrudes at the center of the outer metal 21. A first radiation portion 211 and a second radiation portion 212 are extended in a lengthwise direction to the left and right sides of the feed pin 213. Similarly, a ground pin 233 protrudes at the center of the inner metal 23. With the ground pin 233 being located in the center, a first ground portion 231 and a second ground portion 232 are disposed in a lengthwise direction in parallel to the first radiation portion 211 and the second radiation portion 212. In this case, at least one dielectric member 22 having a specific size may be disposed between the inner metal 23 and the outer metal 21. Instead of the dielectric member, a magnetic member or a hybrid-type block may be disposed.
Not only a structure in which the inner metal 23 is mounted in parallel to the outer metal 21 but also a structure in which they are disposed in parallel without being joined while being spaced apart from each other by means of the dielectric member 22 may be used.
The feed pin 213 of the outer metal 21 is used to feed power to a main board 14 installed inside the portable terminal. The ground pin 233 of the inner metal 23 is grounded to a metal frame 110 used as a part of outer appearance of the portable terminal. However, exemplary embodiments of the present invention are not limited thereto, and thus the feed pin 213 may be used for power feeding not only at one point but also one or more points, and the ground pin 233 may be grounded to the main board 14 or at least one portion thereof may be ground to various surrounding conductors including the metal frame 110 of the portable terminal.
In addition, as illustrated in an exemplary embodiment of the present invention, a shape of the built-in antenna 20 or a cross-sectional shape of the inner metal 23 and its corresponding outer metal 21 may be formed in various manners. That is, the shape of the inner metal 23 may have a concavo-convex structure in which a total length is relatively short and a wider ground area may be ensured.
Referring to
Referring to
When a portion C of the metal frame around the built-in antenna 30 is formed in a slightly open structure, the structure of the metal frame may have the ground extension effect of the antenna radiator 30 while operating as an antenna radiator, thereby being able to improve radiation efficiency.
The metal frame 110 is disposed along an edge of the portable terminal 150, the built-in antenna radiator 30 is installed around the metal frame 110, and a feed portion 31 and a ground portion 32 of the built-in antenna radiator 30 are electrically connected inside the terminal. In this case, the slightly open structure is formed by cutting the metal frame portion C closest in distance to the feed portion 31, and thus a radiation property of the antenna radiator 30 is improved.
Referring to
Referring to
Referring to
Referring to
The most suitable operation is performed in the case of
Referring to
As described above, when a metal frame having a closed structure is implemented to have at least one slightly open structure, a problem occurs in robustness reinforcement which is an original purpose of using the metal frame. Therefore, there is a need to address such a problem.
Referring to
Referring to
According to exemplary embodiments of the present invention, a built-in antenna may exhibit a smooth radiation property even if a metal construction is used in a device, and thus may implement robustness improvement of the device and make the device slim and have an attractive outer appearance. A method of improving antenna efficiency may prevent deterioration of the radiation property of the antenna radiator of the related art by using simple processing, and the metal construction may be used as a radiator.
While the present invention has been shown and described with reference to certain exemplary embodiments thereof, it will be understood by those skilled in the art that various changes in form and details may be made therein without departing from the spirit and scope of the present invention as defined by the appended claims and their equivalents.
Number | Date | Country | Kind |
---|---|---|---|
10-2010-0079223 | Aug 2010 | KR | national |
Number | Name | Date | Kind |
---|---|---|---|
20070115183 | Kim et al. | May 2007 | A1 |
20090002244 | Woo | Jan 2009 | A1 |
20090087011 | Kang | Apr 2009 | A1 |
20090231213 | Ishimiya | Sep 2009 | A1 |
20110021255 | Kim et al. | Jan 2011 | A1 |
Number | Date | Country | |
---|---|---|---|
20120044114 A1 | Feb 2012 | US |