KR20140036426A - Embedded capacitor antenna - Google Patents

Abstract

The present invention relates to a capacitor-loaded antenna used for a wireless communication terminal capable of self-building a capacitor by integrating metal plates which act as an antenna radiator in a printed circuit board and adjusting the interval between the metal plates. To that end, the antenna integrated in a printed circuit board of a mobile terminal includes: a plurality of first metal conductors which are mounted on the printed circuit board separately from each other; at least one second metal conductor which is mounted on the bottom surface of the printed circuit board and is placed on the same vertical line with an adjacent first metal conductor; and a capacitor which is made up by a dielectric mounted between the first and the second conductor.

Description

Capacitor built-in antenna {Embedded Capacitor Antenna}

The present invention relates to an antenna used in a wireless communication terminal, and more particularly, to a capacitor-embedded antenna for directly implementing a capacitor by mounting a metal plate serving as an antenna radiator inside a printed circuit board and adjusting a gap between the metal plates.

Portable terminals require antennas for wireless communication, and recently, internal antennas are more widely used than external antennas for design and performance reasons. Such antennas also use a technique of radiating antennas by using a ground to create antenna resonance using separate capacitor components.

Briefly describing the structure of the capacitor is generally configured in the form of a dielectric between the metal conductor (for example, metal plate). A capacitor is a passive component that stores energy in the form of an electric filed, and is a component that is mounted on a printed circuit board (PCB) inside an electronic device and used for various purposes.

In addition, a dielectric substance is a substance in which a direct current does not flow and acts as an electrical insulator. In order to increase the capacity of the capacitor, materials with high dielectric constant are mainly used, and materials with high dielectric constant are mainly mica, paraffin, and insulating oil.

Capacitance values are an important criterion for evaluating antenna resonance and utilization over various frequency bands. Capacitance, also called capacitance, refers to the ability to store electrical charge. That is, every configuration capable of storing charge has a capacitance, which means that the larger the capacitance value, the more current the capacitor can carry.

1 simplifies the configuration of a parallel metal plate capacitor. As shown in FIG. 1, the capacitance C may vary depending on the thickness of the dielectric 14, the distance 16 between the two metal plates, or the width A of the metal plate.

Referring to FIG. 1, C is capacitance, A is the width of the metal plate, D _k is the dielectric constant existing between the two metal plates, K is the constant, and t is the spacing (distance) 16 between the two metal plates. In order to obtain a capacitor having a high capacitance, the dielectric constant (D _k ) is large [a material having a high dielectric constant], the thickness of the dielectric is thin [a material having a high dielectric constant, and the dielectric thickness for coupling can be reduced. ], The wider the area A of the metal plate and the smaller the gap 16 between the two metal plates, the higher capacitance the capacitor can be implemented. That is, the smaller the gap 16 between the two metal plates, the easier coupling between the metal plates can be achieved. Coupling is generally referred to as coupling, in which various forms of energy are transferred from one object to another. For example, a phenomenon in which electrical energy is transferred from one region to another region in a portable terminal circuit or an electronic component.

However, there are some problems when the capacitor having the above characteristics is mounted on the surface of the printed circuit board. Capacitors mounted on the surface of a printed circuit board have a problem in that the capacitors are separated from the initial mounting position or the signal loss and heat are released depending on the temperature and humidity of the attention. In addition, in the case of a capacitor mounted on the surface of the printed circuit board, a defect occurs in that the printed circuit board moves during the assembling process of the portable terminal or the capacitor is separated from the printed circuit board when the terminal is assembled. In addition, even if there is no problem in the assembly process, if the user drops the portable terminal during use, the capacitor is damaged or fall off from the printed circuit board, there is a problem that the antenna failure and performance is degraded.

Accordingly, there is a need for an antenna that maintains the existing capacitor use and function while eliminating defects in which the capacitor is detached from the printed circuit board during the assembly process and maintaining the antenna performance even during external impact during use.

Accordingly, an object of the present invention is to provide an antenna that eliminates a defect of a capacitor falling from a printed circuit board in a portable terminal assembly process and prevents antenna performance deterioration even during external impact during use.

An antenna embedded in a printed circuit board of a portable terminal for achieving the above object,

A plurality of first metal conductors spaced apart from each other on an upper surface of the printed circuit board and at least one second electrode mounted on a lower surface of the printed circuit board and positioned on the same vertical line as a first metal conductor adjacent to each other; And a capacitor comprising a metal conductor and a dielectric mounted between the first and second metal conductors positioned on the same vertical line.

According to an embodiment of the present invention, the capacitor implemented in the printed circuit board has an effect of eliminating the defect that the capacitor falls off from the surface of the printed circuit board during movement and assembly of the printed circuit board.

Material cost savings can be achieved by eliminating the use of conventional discrete capacitors. In addition, only the antenna pattern (pattern) is present on the surface of the printed circuit board and the remaining antenna configuration can be hidden inside the printed circuit board can be expected to prevent the effect of technology leakage.

1 is a simplified view of the configuration of a parallel metal plate capacitor,
2 is a diagram illustrating antenna performance in a printed circuit board without mounting a capacitor on a printed circuit board surface according to an exemplary embodiment of the present invention;
3 is a view briefly showing the shape and position of a metal plate (antenna pattern) mounted in a printed circuit board according to an embodiment of the present invention;
4 is a view illustrating a state in which two or more metal plates serving as antenna radiators are mounted inside a printed circuit board according to an embodiment of the present invention;
5 to 6 is a view showing a method for adjusting the gap between the metal plate according to an embodiment of the present invention,
7 is a cross-sectional view of various printed circuit boards in accordance with an embodiment of the present invention;
8 is a schematic cross-sectional view showing an enlarged [a] of FIG. 7 having a six-layer structure according to an embodiment of the present invention;
9 is a view showing another embodiment in comparison with FIG. 8 according to an embodiment of the present invention;
10 to 11 is a view showing the performance of the built-in capacitor antenna of the present invention compared to the prior art.

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings. Note that, in the drawings, the same components are denoted by the same reference symbols as possible. In the following description, well-known functions or constructions are not described in detail since they would obscure the invention in unnecessary detail.

The position of the antenna in the portable terminal is mainly located at the top or bottom of the terminal to minimize the hand-wrap phenomenon when the user grips the portable terminal in the hand. In the present invention will be described with an example of a mobile terminal in which the antenna is located at the bottom. In addition, although there are various types of capacitors, the present invention will be described by taking a mobile terminal that implements an internal antenna as an example by using the most representative parallel structure plate-plate capacitor to facilitate understanding of the present invention.

On the other hand, the embodiments of the present invention disclosed in the specification and drawings are merely to illustrate specific technical details of the present invention and to suggest specific examples in order to help understanding of the present invention, but are not intended to limit the scope of the present invention. It is to be understood by those skilled in the art that other modifications based on the technical idea of the present invention are possible in addition to the embodiments disclosed herein.

 The metal conductor used in the present invention includes a metal plate. According to the present invention, instead of mounting a capacitor directly on the surface of a printed circuit board, two or more metal plates serving as antenna radiators face each other at regular intervals to be mounted inside the printed circuit board, and a dielectric existing between the metal plate and the substrate. The capacitor is used together to implement the capacitor and the terminal antenna directly. Referring to FIG. 1, according to an embodiment of the present invention, a capacitance value is changed by adjusting a width (including a length and a shape) or a gap (distance) between metal plates mounted in a printed circuit board, and a desired frequency. The antenna of the band can be implemented.

FIG. 2 is a diagram illustrating the implementation of a capacitor inside a printed circuit board without mounting the capacitor separately on the surface of the printed circuit board according to an exemplary embodiment of the present invention.

FIG. 2A illustrates a case in which separate capacitor elements 50 are mounted on a printed circuit board (PCB) surface. In this case, it can be seen that the capacitor 50 is used to protrude out of the printed circuit board (PCB). On the contrary, in [b] of FIG. 2, two or more metal plates serving as antenna radiators are mounted inside a printed circuit board, and the mounted metal plate directly implements a capacitor so that a separate capacitor 50 is provided as shown in [a] of FIG. 2. ) Is not required outside the printed circuit board.

As shown in [a] of FIG. 2, the antenna and the capacitor 50 installed at the lower end of the portable terminal have a capacitor 50 mounted on the surface of the printed circuit board because the lower end of the terminal receives the greatest impact when the user drops the terminal during use. It often breaks out of its original mounting position or frequently suffers from poor performance. However, as shown in [b] of FIG. 2, the present invention does not mount the capacitor 50 on the surface of the printed circuit board, thereby eliminating or preventing capacitor damage and failure due to the same external impact.

FIG. 3 is a view briefly illustrating a shape and a position of a metal plate (antenna pattern) mounted in a printed circuit board according to an exemplary embodiment of the present invention.

Referring to FIG. 3, when the antenna is a mobile terminal located at the bottom of the printed circuit board 60, the shape and position of the metal plate 100 serving as the antenna radiator as shown in [a], [b], and [c] of FIG. 3. Can be changed according to the required frequency band required. In particular, the metal plate 100 serves as an antenna radiator and simultaneously implements a capacitor. As described in FIG. 1, since the capacitance of the capacitor depends on the width A of the metal plate, the shape, length, and shape of the metal plate 100 may be variously changed according to a required frequency. For example, [a] of FIG. 3 is different from the [b] of FIG. 3, and the metal plate 100 is formed in a curved shape, and [c] of FIG. 3 is a metal plate 100 of [a] and [b] of FIG. You can see that the area of) is wider. For reference, FIG. 3 illustrates only the first metal plate 100 in order to help understand the shape of the metal plate. However, as will be described later, the second metal plate 200 is included in the printed circuit board 60 as shown in FIG. 4. Able to know.

4 is a diagram illustrating a state in which two or more metal plates serving as antenna radiators are mounted inside a printed circuit board according to an exemplary embodiment of the present invention.

Referring to [a] of FIG. 4, two or more metal plates 100 and 200 are mounted inside the printed circuit board 60, and the metal plates 100 and 200 maintain a constant interval t in a form facing each other. Doing. In addition, the metal plates 100 and 200 are mounted so as not to contact each other to induce coupling between the metal plates. As described in FIG. 1, the present invention implements an antenna simultaneously by directly forming a capacitor using two or more metal plates serving as antenna radiators and a dielectric present therebetween. In order to realize the capacitor, a gap is required between the metal plates, and the coupling is performed so that the electrical energy transfer occurs in the gap, so that the metal plates are arranged so as not to contact each other.

FIG. 4B is a cross-sectional view taken along line S-S 'of FIG. 4A, and the coupling is generated between the metal plates 100 and 200, but the coupling portion 70 is strongly shown. As described in FIG. 1, since the magnitude of the capacitance is proportional to the width A of the metal plate, it can be seen that a strong coupling occurs between A-B, C-D, E-F, and G-H in [b] of FIG. 4. And it will be apparent to those skilled in the art that the number and area of the metal plates 100 and 200 for implementing the capacitor-embedded antenna can be added or changed as necessary.

5 to 6 are diagrams illustrating a method of adjusting a gap between metal plates according to an embodiment of the present invention.

First, the reason for adjusting the gap between the metal plate (100, 200) is to change the distance between the two metal plate (100, 2000) as described in Figure 1 can adjust the capacitance value of the capacitor, according to the required frequency band This is because a corresponding antenna can be implemented.

Referring to [a] and [b] of FIG. 5, when the thickness T of the printed circuit board 60 is constant, the distance between the two metal plates is changed by changing the thickness of the metal plates 100 and 200 itself used as the antenna radiator. You can adjust (t ₁ , t ₂ ). It can be seen that the thicker the thickness of the metal plates 100 and 200 itself, the smaller the intervals t ₁ and t ₂ between the metal plates, thereby increasing the capacitance value.

Referring to [a] and [b] of FIG. 6, not only the thickness of the metal plates 100 and 200 itself serving as antenna radiators, but also the positions where the metal plates 100 and 200 are mounted inside the printed circuit board 60 are changed. By adjusting the interval (t ₁ , t _{2 ,} t ₃ ) between the metal plate. The method of adjusting the space | interval between metal plates is not limited to this.

7 is a cross-sectional view illustrating various printed circuit boards according to an exemplary embodiment of the present invention.

The printed circuit board used in the portable terminal has a stack structure in which several layers are stacked. The number of layers is different for each printed circuit board. FIG. 7A shows six layers, FIG. 7B shows 8 layers, and FIG. 7C shows a cross-section of a 10-layer printed circuit board. . The thickness and layer of the printed circuit board may be selected according to the structure and development needs of the portable terminal, and the present invention is not limited to the printed circuit board of 6 layers, 8 layers, and 10 layers.

FIG. 8 is a schematic cross-sectional view of an enlarged [a] of FIG. 7 having a six-layer structure according to an exemplary embodiment of the present invention.

5 to 6, a method of adjusting a gap between metal plates will be described in detail using a mobile terminal using a printed circuit board having a six-layer structure as an example. Referring to FIG. 8 together with FIG. 6, the printed circuit board 60 includes six selectable layers (a-1 layer, b-2 layer, c-3 layer, d-4 layer, e-5 layer, f). -6 layers) and two or more layers can be selected to mount the metal plates 100 and 200 on the selected layer. For example, when the c layer and the d layer are selected as positions to be mounted on the metal plates 100 and 200 in the printed circuit board, the distance t ₁ between the metal plates 100 and 200 is determined according to the selected layers c and d. Accordingly, the capacitance value of the capacitor is also changed as described with reference to FIG. 1. In addition, since the dielectric 14 is present between each of the layers (a, b, c, d, e, f) on which the metal plates 100 and 200 are mounted, a separate capacitor 50 is formed as shown in FIG. Even without mounting on the surface of the substrate 60, the metal plates 100 and 200 and the dielectric 14 present therebetween realize a capacitor function.

9 is a view showing another embodiment compared to FIG. 8 according to an embodiment of the present invention.

9 also shows a cross-sectional view of a printed circuit board 60 composed of six layers as shown in FIG. 9 is the same as the diagram of FIG. 8 in that there are six layers, but the thickness of the dielectric 14 existing between each layer (a, b, c, d, e, f) can be changed to adjust the spacing between layers. Another embodiment is shown. For example, when the c layer and the d layer in the printed circuit board are selected as shown in FIG. 8, and the thickness of the dielectric material 14 existing between the c layer and the d layer is changed, the distance t ₂ between the metal plates 100 and 200 is changed. It can be seen that is reduced than t _{1 of} FIG. Through this, in comparison with the embodiment of FIG. 8, the capacitor may obtain a larger capacitance value in FIG. 9.

In other words, even when the same six-layer printed circuit board is used, the distance between the layers on which the metal plates 100 and 200 are mounted may be adjusted by changing the thickness of the internal dielectric 14, thereby changing the capacitance value of the capacitor. The antenna of the required frequency band can be implemented.

10 to 11 is a view showing the performance of the built-in capacitor antenna of the present invention compared to the prior art.

FIG. 10 shows antenna performance when the capacitor 50 is mounted on the printed circuit board 60 to implement the antenna. FIG. 11 illustrates a printed circuit having two or more metal plates 100 and 200 at regular intervals instead of mounting a capacitor on the surface of the printed circuit board 60 according to the embodiment of the present invention with reference to FIG. 4. The antenna performance of the capacitor is implemented by mounting the inside of the substrate 60 and the two metal plates 100 and 200 and the dielectric 14 between them.

As shown in FIG. 11, it can be seen that the present invention has no difference in terms of antenna performance compared to antenna performance in which a capacitor is mounted on the surface of the printed circuit board 60. As such, the present invention can eliminate the defect that the capacitor 50 falls or breaks when moving the printed circuit board 60 or assembling the portable terminal while maintaining performance similar to that of the prior art, and reducing the material cost and the antenna configuration of the printed circuit board ( 60) Because it can be hidden inside, there is an effect that can prevent the leakage of technology.

In the above description of the embodiment of the present invention with respect to the built-in capacitor antenna through the specification and drawings. Although specific terms have been used, these are merely used in a general sense to easily explain the technical contents of the present invention and to help the understanding of the present invention, and the present invention is not applied only to the above-described embodiments.

14: dielectric
50: capacitor
60: printed circuit board
70: position where the coupling occurs strongly
100: first metal plate
200: second metal plate

Claims (10)

In the antenna built into the printed circuit board of the portable terminal,
A first metal conductor mounted on a top surface of the printed circuit board and spaced apart from each other;
At least one second metal conductor mounted on a bottom surface of the printed circuit board and positioned on the same vertical line as the first metal conductor adjacent to each other;
And a capacitor comprising a dielectric mounted between the first and second metal conductors positioned on the same vertical line. The method of claim 1, wherein the capacitor,
A capacitor built-in antenna, characterized in that one capacitor unit is implemented by the configuration of the first metal conductor, the dielectric and the second metal conductor located on the same vertical line. The method of claim 2, wherein the capacitor,
Capacitor-embedded antenna, characterized in that consisting of a plurality of capacitors spaced apart from each other in the printed circuit board. The method of claim 3, wherein the capacitor,
And a mutual coupling between neighboring capacitors. The method of claim 1, wherein the capacitor,
The capacitance-integrated antenna, characterized in that the size of the capacitance is changed by adjusting the gap between the first and the second metal conductor. The method of claim 1, wherein the capacitor,
The capacitance-integrated antenna, characterized in that the size of the capacitance is changed by adjusting the thickness of the dielectric between the first and second metal conductors. The method of claim 1, wherein the capacitor,
The capacitance of the capacitor, characterized in that the size of the capacitance is changed by adjusting the thickness of the first metal conductor and / or the second metal conductor. The method of claim 1, wherein the first metal conductor and the second metal conductor,
And an internal capacitor formed in an upper layer and a lower layer arbitrarily set among the plurality of layers of the printed circuit board formed of a plurality of layers. The method of claim 1, wherein the second metal conductor,
A capacitor built-in antenna, characterized in that the plurality is mounted on the upper surface of the printed circuit board spaced apart from each other. The method of claim 1, wherein the capacitor,
Change in at least one of the length, width, shape, distance between the first and second metal conductors on the same vertical line, thickness of the dielectric, and combinations thereof, of the first and / or second metal conductors According to claim 1, characterized in that to adjust the resonant frequency of the built-in antenna, the built-in capacitor antenna.

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