KR20090060477A - Antenna gain increase method for mobile communicator and mobile communicator using the same method - Google Patents

Abstract

An antenna gain increase method for a mobile communication terminal and the mobile communication terminal using the same are provided to drastically increase a gain of an embedded gain through a simple method without changing a significant design of the mobile communication terminal, thereby realizing the mobile communication terminal with an improved gain. An antenna is received in a case. An electromagnetic wave shielding unit(66) is formed along with an inner surface of the case to shield an electromagnetic wave generated in the antenna and a circuit device. The electromagnetic wave shielding unit includes a slot(70) in a limited area to which the electromagnetic wave of the antenna is influenced. The slot is mutually coupled with the antenna. The electromagnetic wave shielding unit is EMI(ElectroMagnetic Interference) paint or a metal plate.

Description

Gain gain method for antenna for mobile communication terminal and mobile communication terminal using same {antenna gain increase method for mobile communicator and mobile communicator using the same method}

The present invention relates to a method for increasing a gain of an antenna for a mobile communication terminal and a mobile communication terminal using the same. More specifically, the present invention includes a main unit having a signal processing circuit device and a display unit having a flat panel display device. In a mobile communication terminal such as a cellular phone, a method of increasing a gain of an antenna for a mobile communication terminal capable of greatly improving the gain of an antenna embedded therein without a significant structural change in the main body and a mobile device having an improved gain using the same. It relates to a terminal.

Recently, as society entered the age of full-fledged informatization, rapid technological developments in information and communication fields including IT (Information Technology) followed, and in response, various multimedia services based on high-speed data communication technology Various wireless communication terminals are introduced.

Among them, mobile phones, which are widely used by everyone of all ages, are not only unique voice communications but also digital games, music, video, Internet access, DMB It provides various multimedia services such as Multimedia Broadcasting, and also includes a code division multiple access (CDMA), frequency division multiple access (FDMA), and time division multiple access (TDMA) (including GSM). With the adoption of Wideband CDMA (WCDMA) for the 3rd generation mobile communication, High Speed Downlink Packet Access (HSDPA), and Wibro, which are the 3.5th generation wireless communication standards, the scope of application is gradually increasing.

On the other hand, a mobile communication terminal such as a general mobile phone includes an antenna as an important component for determining its performance, which converts an electrical signal into an electromagnetic wave signal to receive an air signal into the mobile communication terminal, and then uses an internal signal. It serves to send the air to the air. In this case, at least a part of the antenna is an external antenna such as a helical syubby antenna, a retractable antenna in which a helical and a monopole are applied together. (Or protruding antennas) were mainly used. However, the external antennas interfere with the aesthetics by obstructing the light and small size of the product, which is a requirement of the consumer, and are not only inconvenient to use and carry, but also show a relatively large problem of the specific absorption rate (SAR) absorbed by the user.

Accordingly, mobile communication terminals such as plate inverted f atenna (PIFA), inverted f atenna (IFA), folded monopole, dipole, loop, slot, ceramic chip antenna, etc. Built-in antennas (or internal antennas) of the built-in type, called 'tenna', have been introduced, all of which are internally integrated into the antenna. Despite the shortcomings, it is possible to solve various problems in the external antenna, and to design the radiation pattern flexibly to reduce the SAR and to realize the multiband characteristics of more than three bands. Usage is increasing.

1 is a diagram illustrating a mobile phone as an example of a general mobile communication terminal, the specific shape of which is different depending on the model, but a main body including a keypad 12 and a signal processing circuit device for a user's operation. 10 and the display unit 20 on which the flat panel display device 22 is mounted.

At this time, the main body 10 and the display unit 20 of the mobile phone are each protected by a case (case) to complete the appearance of the product, in particular, the case for the main body 10 is the front case with the keypad 12 installed (front case: 14) and combined with it can be divided into a bottom case (16) to accommodate antennas and circuit devices. In addition, electromagnetic shielding means for shielding electromagnetic waves are provided along the inner surfaces of each of the front case 14 and the bottom case 16. As the electromagnetic shielding means, silver flakes are mainly used as a conductive filler. An ethanol-based electromagnetic interference (EMI) paint or sheet-like metal plate is mobilized so that the former is painted on the inner surface of the front 14 and the bottom case 16, and the latter is the front 14 and the bottom case ( 16) Take the interposition along the inner surface.

In addition, the antenna embedded in the main body 10 considers radiation characteristics, voltage standing wave ratio, efficiency, gain, and omnidirectionality as main characteristics. As a kind of PIFA, it is common to install a stamped metal sheet on a plastic carrier by bending it, and various shapes such as a metal sheet, a slot shape, a ground terminal, a parasitic element, a three-dimensional shape, a multilayer structure, etc. It is designed to operate in a single band, dual band, triple band, or quad band by controlling variables. 2 is a photograph showing some examples of a built-in antenna which is mainly used at present.

However, there is still a disadvantage that the general built-in antenna is relatively weak in terms of gain, there is an urgent need for a concrete way to solve this problem.

Accordingly, the present invention has been made to solve the above problems, the ultimate purpose of increasing the gain of the antenna for a mobile communication terminal.

Specifically, the present invention aims to present a method that can be universally applied to all kinds of mobile communication terminals because the gain of the built-in antenna can be greatly improved in a simple and convenient way without significant design change of the mobile communication terminal. The purpose of the present invention is to implement a mobile communication terminal with an improved antenna gain.

In order to achieve the above object, the present invention provides a method for increasing antenna gain of a mobile communication terminal including a main body unit in which an antenna and a signal processing circuit device are embedded, and a display unit connected to the main body unit and equipped with a flat panel display device. And casing the main body to provide an electromagnetic shielding means along an inner surface of a case accommodating the antenna and the signal processing circuit device, wherein the electromagnetic shielding means is coupled to the antenna within a limited region of the electromagnetic shielding means. It provides a method of increasing the antenna gain of a mobile communication terminal comprising the step of forming a slot.

In this case, the case is characterized in that the non-conducting bar, the electromagnetic shielding means is an EMI paint painted along the inner surface of the case, the slot decapsulates the EMI paint or the EMI along the inner surface of the case remaining except the slot It is characterized in that it is formed by painting or the electromagnetic shielding means is a sheet-shaped metal plate covering the inner surface of the case, the slot is characterized in that formed by cutting the metal plate.

In addition, the present invention provides a mobile communication terminal comprising a main body unit with a signal processing circuit device is built-in, and a display unit connected to the main body unit and a flat panel display device, the case for accommodating the signal processing circuit device; An antenna housed in the case; A mobile communication terminal including an electromagnetic shielding means formed along an inner surface of the case and shielding electromagnetic waves generated from the antenna and the circuit device, the slot being coupled to the antenna in a limited area affected by the electromagnetic field of the antenna. to provide.

In this case, the case is an insulator, and the electromagnetic shielding means includes an EMI paint applied to the inner surface of the casing or a metal plate covering the inner surface of the casing, and the case is exposed by the slot.

The present invention provides a concrete way to greatly improve the gain of the built-in antenna. Therefore, the present invention has the advantage of improving the gain of the built-in antenna, while maintaining the various advantages appear only in the built-in antenna compared to the external antenna. In addition, the present invention has the advantage that it is possible to improve the gain of the antenna in a simple and convenient way without significant design changes to be universally applicable to all kinds of mobile communication terminal.

Hereinafter, the present invention will be described in detail with reference to the accompanying drawings.

Prior to the full description, the technical principles of the present invention will be briefly reviewed. The present invention aims to greatly increase the gain of an antenna without significant design changes of a mobile communication terminal such as a mobile phone. Attention was paid to the formation of electromagnetic shielding means.

That is, a circuit device for signal processing including an antenna is embedded in a case of a general mobile communication terminal, and electromagnetic shielding means is formed along an inner surface of the case to shield electromagnetic waves generated from the antenna and the circuit device. In this case, since the electromagnetic shielding means is usually used ethanol-based EMI paint or sheet metal plate with a silver flake conductive filler, the electromagnetic shielding means can be considered as a conductor close to the antenna. On the other hand, according to the principle of the cabinet (babinet) associated with the antenna, when a slot is assigned to a conductor placed in the electromagnetic field of the antenna, the slot can be interpreted as a conductor bar close to the antenna as a separate radiator having a duality.

That is, FIG. 3 is an equivalent view of the relationship between the slot 52 of the antenna 65 and the conductor 65 placed in the electromagnetic field thereof, and is placed in the electromagnetic field of the antenna 52 as shown in FIG. When the slot 70 exists in the conductor 65, it can be represented by the conductor bar 71 which adjoins the antenna 52 like (b) of the right side. At this time, if the voltage applied to the antenna 52 is V1, the antenna 52 side is port 1, and the conductor bar 71 is port 2, no separate power is applied to the port 2. Therefore, it is summarized as Equation 1 below.

<Equation 1>

Here, I1 and I2 are currents flowing through the antenna 52 and the conductor bar 71, respectively, and Z11 and Z22 are their own impedances of the antenna 52 and the conductor bar 71, respectively, and Z12 and Z21 are the respective antennas ( 52 and the mutual impedance of the conductor bar 71. As can be seen from this, there is a mutual impedance between the antenna 52 and the conductor film 71 due to the coupling (coupling). If equation 1 is solved, the current I 1 is arranged as in Equation 2 below. And mutual impedance of the conductor bar 71 are related to each other, the conductor bar 71 affects the current flowing through the antenna 52 affects the gain of the antenna 52.

<Equation 2>

Accordingly, by adjusting the length w of the conductor bar 71 and the distance d between the antenna 52 and the conductor bar 71, the interaction between them may help or hinder the radiation of the antenna 52. In other words, the current induced in the conductor bar 71 and the antenna 52 using the length (w) of the conductor bar 71, the distance (d) between the antenna 52 and the conductor bar 71 as a control variable. When the current in phase is in phase, the radiation of the antenna 52 can be made larger. At this time, referring to the left side (a), the length w of the conductor bar 71 is the length w of the slot 70, and the distance d between the antenna 52 and the conductor bar 71 is the antenna. Corresponding to the antenna 52 in the region of the electromagnetic field of the antenna 52 in the conductor plate 65 proximate to the antenna 52 corresponding to the distance d between the 52 and the slot 70. If the slot 70 is formed, the radiation of the antenna 52 can be increased, and the gain of the antenna 52 can be increased.

Accordingly, the present invention is characterized by increasing the gain of the antenna 52 by applying a slot to the electromagnetic shielding means installed along the inner surface of the case of the mobile communication terminal.

4 is an exploded view showing a mobile phone, which is an example of a mobile communication terminal, as a preferred embodiment of the present invention. In this case, the present invention is not limited to the cellular phone, and it can be easily understood by those skilled in the art through the following description that the present invention is applicable to all kinds of mobile communication terminals employing a built-in antenna.

As can be seen, the cellular phone according to the present invention can be divided into a main body 50 having an antenna 52 and a circuit device 54 for signal processing, and a display 80 having a flat panel display. In this case, the bar type, the folder type, and the slide type are generally classified according to the connection method of the main body part 50 and the display part 80. The flat panel display device is a liquid crystal display device, a plasma display panel device (PDP), a field emission display device (FED), an electroluminescence display device. : ELD) all kinds are available.

These body parts 50 and the display part 80 are protected by respective cases and at the same time complete the appearance of the product.

At this time, the case for the main body 50 is divided into a front case 62 for exposing the keypad, and the bottom case 64 coupled to it to accommodate the antenna 52 and the circuit device 54 therein, Along the inner surface thereof, an electromagnetic shielding means 66 is formed. In this case, due to holes for exposing the keypad along the inner surface of the front case 62, the electromagnetic shielding means is formed only in a part of the front case 62, except for the mounting position of the antenna 52 along the inner surface of the bottom case 64. Electromagnetic shielding means 66 may be formed over the area.

In the bottom case 64 of the mobile phone according to the present invention, a slot 70 having an elongated groove shape is provided in a part of the electromagnetic shielding means 66 close to the mounting position of the antenna 52, and through the bottom case 64 In this case, the bottom case 64 is made of an insulator such as polycarbonate, and the slot 70 is located at a point where the current of the antenna 52 is most concentrated, that is, the point where the current density is the highest. Orthogonal to the current direction of the flowing antenna, the length of the slot 70 preferably has an elongated groove shape within a range equal to or less than the length of the antenna 52. In this case, the slot 70 may be curved, etc., unlike the straight form of the figure. In addition, when the electromagnetic shielding means 66 is an EMI paint, the method for forming the slot 70 decapsulates the EMI paint coated on the entire inner surface of the bottom case 64 except for the mounting position of the antenna 52. De-Cap) or the bottom case 64 can be implemented in such a way as to apply only to the remaining parts except for the corresponding position when the EMI paint, and, when the electromagnetic shielding means 66 is a sheet-shaped metal plate, the completed metal plate It can be implemented through a punching process, such as to cut into a groove shape. As a result, a portion of the insulator bottom case 64 is exposed through the slot 70.

Hereinafter, an experimental example for checking the gain and degree of the antenna for a mobile communication terminal according to the present invention will be described. At this time, the mobile phone mobilized in this experiment was selected as the two types of the most commonly used clamshell and slide type.

First, FIGS. 5 to 7, 8a, 9a, 10a, 11a, 12a, 13a, 14a, and 15a are each a folding cell phone provided with a slot as a first experimental example of the present invention. Figures for explaining the experimental results of. At this time, Figure 5 shows a first mobile phone used in the first experimental example of the present invention, Figure 6 is a simulation shape showing the main components of the first mobile phone, Figure 7 is a slot formed in the bottom case of the first mobile phone You can check the photo. 8A is a result of simulating the gain pattern of the antenna for the first cellular phone having a slot as a current, and FIG. 8B is a result of simulating the antenna gain pattern of the first cellular phone without a slot as a current for comparison. 9A, 10A, 11A, and 12A are simulation results of a main part of the first cellular phone in which the slots are formed, respectively, as shown in FIG. 9B, 10B, 11B, and 12B, respectively. This is the result of simulating the main part of the first cell phone without current.

In addition, Figure 13a is a result of measuring the frequency characteristics with the network analyzer, respectively, in the open and closed state of the first cell phone formed slot, Figure 14a is a result of simulating the frequency characteristics in the state of opening and closing the first cell phone formed slot, respectively, 15A is a result data of calculating efficiency through various conditions measured in the state of opening and closing the first cellular phone in which a slot is formed. 13B, 14B, and 15B are results of experiments under the same conditions as those of FIGS. 13A, 13B, 14B, and 15B for the first mobile phone without a slot for comparison, respectively.

First, as shown in FIG. 5, the first mobile phone used in the first experimental example of the present invention has a folder type that is folded or unfolded by being connected to the main body and the display by a hinge. That is, as shown in FIG. 6, the first mobile phone is divided into a main body part 50 and a display part 80, among which the main body part 50 has a main PCB (Printed Circuit Board) 56 and an antenna ( 52) and a first electromagnetic shielding means 66 for shielding electromagnetic waves generated therefrom, and the display portion 80 includes a main PCB 56 of the main body portion 50 and a flexible circuit board (FPCB). A display PCB 82 connected to a conductive connection member and mounted with a flat panel display device and a second electromagnetic shielding means 84 for shielding electromagnetic waves generated therefrom are provided.

At this time, the slot is formed according to the present invention is the first electromagnetic shielding means 66 of the body portion 50, as can be seen in Figure 7 of the bottom plate 64 except the mounting position of the antenna 52 The slot 70 was formed by decapturing an arbitrary point close to the antenna 52 among the first electromagnetic shielding means 66 formed on the front surface with a width of 2 mm and a length of 10 mm.

As a result, the gain of the antenna 52 (from 150 [A / m] to 170 [A / m]) is greatly improved by the slot as shown in FIGS. 8A and 8B, while FIGS. 9A and 9B, 10A and 10b, 11a and 11b, 12a and 12b, for example, current distribution of other parts, such as the main PCB 56, the first electromagnetic shielding means 66, the FPCB 90, the display PCB 82, and the like. It can be seen that there is no change. In addition, as can be seen from the comparison of FIGS. 15A and 15B and FIGS. 16A and 16B, the efficiency of the antenna is greatly improved by the slots.

Meanwhile, FIGS. 16 to 18, 19A, 20A, 21A, and 22A are diagrams for describing experimental results of the slide-type mobile phone as the first experimental example of the present invention.

At this time, Figure 16 shows a second mobile phone used in the second experimental example of the present invention, Figure 17 is a view showing a simulation of the main part of the second mobile phone, Figure 18 is a slot position of the bottom case of the second mobile phone Photo to check. 19A is a result of simulating the antenna gain pattern of the second mobile phone having a slot as a current, and FIG. 19B is a result of simulating the antenna gain pattern of the second mobile phone without a slot as a current for comparison. FIG. 21A is a result of measuring the frequency characteristics of the second mobile phone with a slot formed by a network analyzer, and FIG. 21A is a result of measuring the radiation characteristics of the antennas in the open and closed states of the second mobile phone with a slot formed therein, and FIG. 2 Efficiency data is calculated through various conditions measured in the open and closed state of the mobile phone. 20B, 21B, and 22B are results of experiments under the same conditions as those of FIGS. 21A, 22B, and 23B for the second mobile phone without a slot for comparison, respectively.

Hereinafter, the same reference numerals will be given to the same parts performing the same role as the first experimental example, and redundant description thereof will be omitted.

First, as illustrated in FIG. 16, the second mobile phone used in the second experimental example of the present invention is a sliding type in which the display unit slides in an up-down manner with respect to the main body unit. That is, as shown in FIG. 17, the second mobile phone is divided into a main body part 50 and a display part 80 which slides up and down in a state of being superimposed on an upper surface thereof, and in the main body part 50, a main PCB for a circuit device. And an antenna 52 and a first electromagnetic shielding means 66 for shielding electromagnetic waves generated therefrom, and the display unit 80 includes a display PCB on which a flat panel display device is mounted and shielding electromagnetic waves generated therefrom. The second electromagnetic shield means for 84 is provided.

At this time, the portion in which the slot is formed according to the present invention is the first electromagnetic shielding means 66 of the body portion 50, as shown in Figure 18, the first electromagnetic wave formed on the front surface of the bottom plate 64, except for the antenna mounting position Any two points close to the antenna 52 of the shielding means 66 were decapsulated to a width of 2 mm and a length of 10 mm to form a slot.

As a result, as can be seen in Figs. 19A and 19B, the current of the antenna of the second mobile phone is 500 [A / m] when the slot is present and 550 [A / m] otherwise, the difference between the two is approximately 50 [A / m]. In other words, when there is a slot, the current of the antenna is greatly increased, and thus the radiation is increased, so the gain is also improved. In addition, the presence or absence of the slot does not affect the resonant frequency as shown in FIGS. 20A and 20B, but the efficiency is 2.096 at all frequencies depending on the presence or absence of the slot as shown in FIGS. 21A and 21B and FIGS. 22A and 22B. The gain increased 0.41dB ~ 1.07dB by increasing% ~ 7.21%, indicating that the gain and efficiency of the antenna were greatly improved.

On the other hand, it can be seen that the slot according to the present invention greatly improves the gain of the built-in antenna through the experimental example described above. The technical idea of the present invention is commonly applied to all kinds of mobile communication terminals. Unlike the example, when the first electromagnetic shielding means is a sheet-shaped metal plate other than the EMI paint, the same result can be obtained by forming a slot by forming a slot at a corresponding position. Accordingly, the present invention may be variously modified, but all should fall within the scope of the present invention as long as the technical spirit of the present invention is satisfied, which can be easily understood by those skilled in the art through the following claims.

1 is a perspective view of a mobile phone which is an example of a general mobile communication terminal.

Figure 2 is an exemplary photo of a built-in antenna of a typical mobile phone.

Figure 3 is a schematic diagram for explaining the technical principle of the present invention.

Figure 4 is a photograph showing the internal structure of the mobile phone according to the present invention.

5 is a photograph of a mobile phone for the first experimental example of the present invention.

6 is a simulation of the main part of the mobile phone of FIG.

Figure 7 is a photograph showing the slot position of the mobile phone according to the first experimental example of the present invention.

8A and 8B are diagrams showing antenna gains depending on whether slots are present.

Figures 9a and 9b is a view showing the current distribution of the mobile phone with or without a slot, respectively.

10A and 10B are diagrams showing current distribution of mobile phones depending on whether slots are present.

11A and 11B are diagrams showing current distribution of mobile phones depending on whether slots are present.

12A and 12B are diagrams showing current distribution of mobile phones depending on whether slots are present.

13A and 13B are graphs of frequency characteristics of an open and closed state of a mobile phone according to whether slots are present.

14a and 14b are graphs simulating the frequency characteristics of the open and closed state of the mobile phone according to the presence or absence of slots, respectively.

15a and 15b are characteristic data for the open and closed states of the mobile phones, respectively, with or without slots;

16 is a photograph of a mobile phone for a second experimental example of the present invention.

17 is a simulation of the main part of the mobile phone of FIG.

18 is a photograph showing the slot position of the mobile phone according to the second experimental example of the present invention.

19A and 19B are diagrams showing antenna gains depending on whether slots are present.

20A and 20B are graphs of frequency characteristics of an open and closed state of a mobile phone according to whether slots are present.

21A and 21B are simulation diagrams of frequency characteristics of an open and closed state of a mobile phone with or without a slot, respectively.

22a and 22b are characteristic data for the open and closed states of the mobile phone, respectively, depending on the presence or absence of a slot;

<Description of the symbols for the main parts of the drawings>

50: main body 52: antenna

54 circuit device 62 front case

64: fallum case 66: electromagnetic shielding means

70: slot 80: display unit

Claims (6)

An antenna gain increasing method of a mobile communication terminal comprising a main body portion having an antenna and a signal processing circuit device and a display portion having a flat panel display device, The electromagnetic shielding means is provided along the inner surface of the housing housing the antenna and the signal processing circuit by casing the main body, and the slot is coupled to the antenna within a limited area of the electromagnetic field of the antenna. Gain increasing method of the antenna for a mobile communication terminal comprising the step of forming a. The method of claim 1, The case is a method of increasing the gain of the antenna for the non-conducting mobile communication terminal. The method according to claim 1 or 2, The electromagnetic shielding means is an EMI paint painted along the inner surface of the case, The slot is a method of increasing the gain of the antenna for the mobile communication terminal is formed by decapsulating the EMI paint or the EMI paint along the inner surface of the case other than the slot. The method according to claim 1 or 2, The electromagnetic shielding means is a sheet-shaped metal plate covering the inner surface of the case, The slot is a method of increasing the gain of the antenna for a mobile communication terminal formed by cutting the metal plate. A mobile communication terminal comprising a main body unit in which a signal processing circuit device is incorporated, and a display unit connected to the main body unit and a flat panel display device mounted thereon, A case accommodating the signal processing circuit device; An antenna housed in the case; And electromagnetic shielding means formed along an inner surface of the case and shielding electromagnetic waves generated from the antenna and the circuit device, the slots being coupled to the antenna in a limited area of the antenna. The method of claim 5, The case is an insulator, and the electromagnetic shielding means includes an EMI paint applied to the inner surface of the casing or a metal plate covering the inner surface of the casing, wherein the case is exposed by the slot.

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