KR20100112507A - Internal antenna and portable communication terminal using the same - Google Patents

Abstract

PURPOSE: A built-in antenna and a mobile communications terminal thereof are provided to minimize the change of a reception frequency band due to the body contact of a user by placing the center frequency of a second antenna in the edge of the reception frequency band of a built-in antenna. CONSTITUTION: A first antenna(210) comprises a first antenna pattern(211) formed on a first dielectric layer(213). A second antenna(220) comprises a second antenna pattern(221) formed in the second dielectric layer(222) and a second dielectric layer. The second dielectric layer has a dielectric constant higher than that of the first dielectric layer. The first and the second antenna are electro-magnetically combined in order to be reciprocity resonant. The first antenna pattern and the second dielectric layer are branched around the same feeding point.

Description

Built-in antenna and portable communication terminal using it {INTERNAL ANTENNA AND PORTABLE COMMUNICATION TERMINAL USING THE SAME}

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an antenna, and more particularly to a small antenna that can be incorporated in a portable communication terminal.

Due to the recent development of semiconductor technology and various communication technologies, various portable communication terminals are developed and spread. For example, devices including wireless communication functions include various devices such as notebooks, PMPs, mobile phones, and navigation devices.

Wireless communication services provided through the above-described devices are various, such as broadcast service (satellite or terrestrial DMB), communication service, Internet service, and the like, and in particular, the broadcast service may be used while on the move, and thus may include both internal and external antennas. It may also be provided in a form.

The above-mentioned devices are products requiring portability, and in order to use various types of services as described above, a small and high-performance antenna is required. After all, as a means to meet the volume and design elements, the above-mentioned devices are being developed and spread in the direction of adopting the built-in antenna.

1 is a view schematically showing a conventional built-in antenna. Referring to FIG. 1, the embedded antenna 100 includes a dielectric layer 110 and a radiation surface 130 formed on the dielectric layer 110.

The radiation surface 130 is excited by a power supply line running horizontally of the dielectric layer 110, and a coaxial cable (not shown) may be mainly used as a connection cable. The inner conductor of the coaxial cable is electrically connected to the radiating surface.

Since the above-described built-in antenna 100 is mainly applied to portable communication terminals, the radiation surface 130 is formed on the dielectric layer 110 having a low dielectric constant due to the size constraint.

Due to the low dielectric constant dielectric layer 110, the embedded antenna 110 may cause a problem that the radiation characteristics of the antenna, such as a hand phantom or hand effect, in which the reception frequency band shifts when the user approaches the body. .

2 is an experimental result of frequency band shift due to a hand phantom of a conventional internal antenna. The dotted line shown in FIG. 2 is a graph of the frequency (f ₁ , f ₂ ) band to be received by the built-in antenna, and the dotted line shown in FIG. 2 is the frequency (f ₁ ^′) received by the built-in antenna due to hand phantom or hand effect. , f ₂ ^' ) is a graph showing the shifted band.

As a method for minimizing the change in radiation characteristics of the built-in antenna due to the above-described hand phantom, a method of designing the part in which contact with a user frequently is mounted and a location where the built-in antenna is mounted are spaced apart as much as possible, a method using an external antenna, The method of using a broadband antenna can be applied.

However, the above methods for suppressing the hand phantom have problems in applying to the limited size of the portable communication terminal.

In addition, a method of using a dielectric layer having a high dielectric constant has been proposed, but there are problems such as increased loss, reduced bandwidth, and induction of parasitic parameters. That is, when a dielectric having a high dielectric constant is used in consideration of the physical length of the antenna, antenna bandwidth is reduced and antenna propagation loss is increased.

The present invention is to provide a built-in antenna that can be mounted in a limited space while minimizing changes in the radiation characteristics of the antenna, such as frequency shift due to the user's body contact.

Built-in antenna according to the first aspect of the present invention,

A first antenna having a first antenna pattern formed on the first dielectric layer;

A second antenna having a second antenna pattern formed on a second dielectric layer having a higher dielectric constant than the first dielectric layer,

The first antenna pattern extends to the second dielectric layer.

A second antenna branched from the start point of the first antenna pattern is formed in the second dielectric layer.

In the built-in antenna according to the second aspect of the present invention, the second antenna has a center frequency located at an edge of a frequency band that the built-in antenna can receive.

The second antenna according to the third aspect of the present invention has a higher Q value than the first antenna.

The built-in antenna according to the present invention includes a first antenna having a center frequency different from the center frequency of the frequency band that the built-in antenna is intended to receive, and a second antenna formed on a dielectric layer having a higher dielectric constant than the first antenna. It is possible to minimize the decrease in reception sensitivity due to the change in the frequency band due to body contact. In particular, according to the present invention, since the center frequency of the second antenna is located at the edge of the reception frequency band of the built-in antenna, the change in the reception frequency band due to contact with the user's body can be minimized.

The built-in antenna according to the present invention can minimize the change in the radiation characteristics of the hand phantom and thereby the antenna due to physical contact with the user while maintaining a small feature applicable to a limited space, such as a portable communication terminal.

Hereinafter, with reference to the accompanying drawings will be described an embodiment of the present invention; In describing the present invention, detailed descriptions of related well-known functions or configurations are omitted in order not to obscure the subject matter of the present invention.

The present invention relates to a built-in antenna which resonably couples between antennas in which respective antenna patterns are formed on dielectric layers having different dielectric constants, and includes a higher dielectric constant (or more) among two antennas resonantly coupled. The invention relates to a structure in which a center frequency of an antenna having a high Q value is located at one of edges of a frequency band that an embedded antenna is to receive.

After all, the present invention resonantly couples two antennas with different cue (Q) values, in particular the center of the antenna with the higher cue (Q) of the two and not affected by physical contact with the user. The present invention relates to an integrated antenna capable of minimizing hand phantom or hand effect such as frequency band shift due to physical contact with a user by placing a frequency at an edge of a receivable frequency band of the built-in antenna. to be.

3A and 3B are cross-sectional views of built-in antennas according to the present invention. The embedded antennas 200 illustrated in FIGS. 3A and 3B include first and second antennas 210 and 220 having an antenna pattern 211 formed on respective dielectric layers 213 and 222 having different dielectric constants. do.

The first antenna 210 has a first antenna pattern 211 is formed in the first dielectric layer 213, the second antenna 220 has a higher dielectric constant than the first dielectric layer 213 A second dielectric layer 222 and a second antenna pattern 221 formed on the second dielectric layer 222. The first and second antennas 210 and 220 may be electromagnetically coupled to each other so as to be mutually resonant, and may be disposed vertically.

The first antenna pattern 211 extends such that a feed point 212 is in contact with the second dielectric layer 222. The first antenna pattern 211 may be formed to branch to the second dielectric layer 222 around the same feed point, and the feed point 212 may have an antenna pattern on the dielectric layer. It means a point. That is, the first antenna pattern 211 and the second antenna pattern 220 may be formed to branch from the same feed point.

Polycarbonate (ε _r = 3) may be used as the first dielectric layer 213, and the second dielectric layer 222 may have a higher dielectric constant and cue than that of the first dielectric layer 213. Dielectric materials with Q) values can be used. The first dielectric layer 213 may include a dielectric material having a relative dielectric constant in a range of 0 to 10, and the second dielectric layer 222 may have a dielectric material in a range of 4 to 100 relative dielectric constant. This can be used. When the relative dielectric constant range of the first dielectric layer 213 and the relative dielectric constant range of the second dielectric layer 222 overlap in the range of 4 to 10, but are included in the second dielectric layer 222 in the overlapping range, The first dielectric layer 213 may use a material having a dielectric constant lower than that of the second dielectric layer 222.

3A illustrates a structure in which a first antenna pattern 211 is formed on an upper surface of the first dielectric layer 213, and FIG. 3B illustrates a structure in which a first antenna pattern 211 is formed on a bottom surface of the first dielectric layer 213. 2 shows an example of each formed to face the top surface of the dielectric layer 222. The first and second antennas 210 and 220 constituting each of the internal antennas 200 shown in FIGS. 3A and 3B are resonably coupled in a frequency band to which the internal antennas 200 configured to receive are configured.

Means the frequency band (center frequency f ₁₎ and the second frequency band of the antenna 220 being (f _2), the resonance can be electromagnetically coupled (f ₁ + f ₂₎ of the first antenna 210 As shown in the graph shown in Figure 4 (graph of the frequency band having a center frequency f ₃ ) it means that the built-in antenna 200 to be implemented in the present invention implements the waveform of the frequency band to be received.

In order to be resonably coupled electromagnetically between the first antenna 210 and the second antenna 220, the first and second antenna patterns 213 and 221 must be positioned to correspond to each other, and the first antenna ( A distance L spaced apart on the three axes x, y, and z between the 210 and the second antenna 220 is included within at least 1 mm, and the thickness d ₁ of the first dielectric layer 213 is 2. It is preferably included within mm, and the thickness d ₂ of the second dielectric layer 222 is included within 4mm.

4 is a graph illustrating a built-in antenna according to the present invention. 4 is a graph showing a frequency band to be received by the built-in antenna according to the present invention, and center frequencies f ₃ and f ₃ ^′ in the frequency band.

4 is a graph showing the center frequencies f ₁ and f ₁ ^′ of the first antenna and a frequency band that can be received, and the dashed-dotted line shown in FIG. 4 is a frequency band and a center frequency of the second antenna. f ₂ , f ₂ ^' ).

The built-in antenna has a center frequency f ₃ , f ₃ ^′ in the receivable frequency bands A, B, and each of the receivable frequency bands A, B has at least one edge e ₁ , e ₂ , e ₃ , e ₄ ).

The first antenna has a frequency band in the state of being moved from a frequency band to be actually received (center frequency is f ₁ , in preparation for the reception of a frequency band (solid graph) of the built-in antenna due to hand phantom, etc., f ₁ ^' ).

In addition, the second antenna is formed on a dielectric layer having a higher dielectric constant than the first antenna, so that the second antenna may have a higher Q value than the first antenna, and the center frequency f ₂ , f ₂ ^′ ) are located at the edge of the frequency band that the built-in antenna can receive.

The second antenna has a center frequency (f ₂ , f ₂ ^' ) to be included within ± 30% of the frequency corresponding to the edge (e ₁ , e ₂ , e ₃ , e ₄ ) of the frequency band of the built-in antenna Can be formed. In a practical example, if the frequency of the edge where the center frequency of the second antenna is to be located is 820 MHz, the center frequency of the second antenna may be located between 570 MHz and 1.3 GHz. As another example, if the frequency of the edge is 1.8 kHz, the center frequency of the second antenna may be located between 1.26 ~ 2.7 GHz. More preferably, the second antenna has a center frequency (f ₂ , f ₂ ^' ) ± ± around the frequency corresponding to the frequency band edge (e ₁ , e ₂ , e ₃ , e ₄ ) of the built-in antenna It may be more desirable to be formed to be included within 20%.

In the built-in antenna according to the present invention, the first and second antennas are coupled to each other so as to be resonant with each other, thereby enabling transmission and reception of a signal in a frequency band to be actually received. In addition, since the center frequency of the second antenna having a high Q value is located within a predetermined range of the edges (e ₁ , e ₂ , e ₃ , e ₄ ) of the built-in antenna, the dielectric characteristics of the dielectric due to contact with the user (dielectric Constant) and consequent shifts in frequency bands.

The built-in antenna according to the present invention can minimize the shift of the frequency band due to the hand phantom and the deterioration of the reception sensitivity without increasing the size. That is, the present invention can be implemented shorter than the length corresponding to the frequency band of the built-in antenna of the first antenna designed to minimize the required space.

5 is a graph illustrating the first and second antennas according to the present invention. 5A is a graph illustrating the center frequencies f ₁ and f ₁ ^′ of the first antenna and the frequency bands thereof, and FIG. 5B is the center frequencies f ₂ and f ₂ ^′ of the second antenna and the frequency bands thereof (solid line). ) And a frequency band (dotted line) after being combined with the first antenna.

6 is a graph for comparing a frequency band change due to the hand phantom of the conventional internal antenna and the internal antenna according to the present invention. 6A and 6B, the dotted line graph is a graph showing the frequency band to be received, and the solid line is a graph showing the frequency band shifted due to the hand phantom.

FIG. 6A is a diagram illustrating a receivable frequency band (a dashed-dotted line) of a conventional antenna and a graph (solid line) in which a receivable frequency band is shifted due to a hand phantom, and FIG. 6B is a built-in antenna according to the present invention. This is a graph showing the case where a hand phantom is generated.

Comparing a of FIG. 6 and b of FIG. 6, it can be seen that the fluctuation range of the receivable frequency band due to the hand phantom in FIG. 6b is small. In particular, the built-in antenna according to the present invention illustrated in FIG. 6B includes a frequency band which the frequency band moved due to the hand patum is intended to receive, thereby minimizing a reduction in reception rate due to the movement of the frequency band.

7 is a diagram illustrating a portable communication terminal mounting a built-in antenna as a second embodiment of the present invention. 7 is a diagram illustrating an example in which the portable communication terminal illustrated in FIG. 7 includes a built-in antenna according to a first embodiment of the present invention having a form as illustrated in FIG. 3A or 3B.

The portable communication terminal 300 according to the present embodiment may be configured to include a built-in antenna of the same type as the built-in antenna described with reference to FIGS. 3A and 3B, and the detailed configuration thereof will be described with reference to FIGS. 3A and 3B. The explanations shall apply mutatis mutandis.

FIG. 8 is a diagram illustrating a portable communication terminal in the form of a wrist watch equipped with a built-in antenna as a third embodiment of the present invention. The portable communication terminal 400 according to the present embodiment may be configured to include a built-in antenna of the same type as the built-in antenna described with reference to FIGS. 3A and 3B. It is assumed to be the same as the built-in antenna shown in FIG. 3B.

That is, the portable communication terminal according to FIG. 8 includes a first antenna having a first antenna pattern formed on a first dielectric layer and a second antenna pattern formed on a second dielectric layer having a higher dielectric constant than the first dielectric layer. The antenna may include two antennas, and the first antenna pattern may include a built-in antenna extending inside the case (or housing) extending to the second dielectric layer. In the case of mounting the built-in antenna of the above-described type, the portable communication terminal may include a housing or a case made of metal or the like.

Wireless communication terminal 400 according to the present embodiment is a portable digital devices (PDA, PMP, laptop, smart phone, etc.) having a DMB viewing function or the Internet or wireless communication function or both the DMB and the Internet and wireless communication function or Navigation, etc. for receiving a GPS signal may all be applicable. That is, the portable communication terminal 400 according to the present invention may be an antenna and all small electronic devices of a form required to be carried.

The portable communication terminal 400 may be a user's body wearable form, such as a wrist watch, and may include a pin support 442, a pin 451, a hole 443, and strings 421 and 431 extending from the body.

9A to 9C are cross-sectional views illustrating different examples in which the built-in antenna according to the present invention is mounted on the wireless communication terminal illustrated in FIG. 8. 9A to 9C illustrate examples of cases in which portable communication terminals are made of a dielectric material.

FIG. 9A illustrates an example in which the first antenna 421 is configured by a case 421b on which components of a portable communication terminal are mounted and a first antenna pattern 421a formed on an upper surface (outer wall) of the case 421b. A first antenna 421 composed of a case 421a and the first antenna pattern 421a and a second antenna pattern 422b formed on the dielectric layer 422a having a higher dielectric constant than the case 421b. It may include an antenna 422. The feed point 421c of the first antenna pattern 421a extends to the dielectric layer 422a. That is, FIG. 9A illustrates an example of a portable communication terminal in which the first antenna pattern 421a is formed on the outer wall of the case 421b.

FIG. 9B illustrates an example of a portable communication terminal in which a first antenna pattern 421a is formed on an inner wall of a case 421b, and FIG. 9C shows that the first antenna pattern 421a is formed by in-mold injection molding as a film. FIG. 3 is a diagram illustrating a structure formed to be embedded in the case 421b.

The first antenna pattern 421a illustrated in FIGS. 9A to 9C is attached to an outer wall or an inner wall of the case 421b in the form of a film, or the case as an in-mold in the injection molding of the case 421b. May be buried in. In addition, the second antenna 422 may be formed on a printed circuit board, and the feed point 421c of the first antenna pattern 421a when the second antenna 422 is formed on a printed circuit board. May extend to the printed circuit board.

1 is a view showing a built-in antenna according to the prior art,

2 is a graph illustrating a change in frequency band due to a hand phantom of a conventional built-in antenna,

3a and 3b are cross-sectional views of a built-in antenna according to a first embodiment of the present invention,

4 is a graph illustrating a built-in antenna according to a first embodiment of the present invention;

5 is a graph illustrating the first and second antennas according to the present invention;

6 is a graph for comparing the frequency band change due to the hand-phantom of the conventional internal antenna and the internal antenna according to the present invention;

7 is a view showing a portable communication terminal mounted with a built-in antenna according to a second embodiment of the present invention,

8 illustrates a portable communication terminal according to a third embodiment of the present invention;

9A to 9C are cross-sectional views illustrating an example in which a built-in antenna is mounted on the portable communication terminal illustrated in FIG. 8.

Claims (27)

In the built-in antenna, A first antenna having a first antenna pattern formed on the first dielectric layer; A second antenna having a second antenna pattern formed on a second dielectric layer having a higher dielectric constant than the first dielectric layer, And the first antenna pattern extends to the second dielectric layer. According to claim 1, And the second antenna has a higher Q value than the first antenna. The method of claim 2, And the dielectric constant of the second antenna is greater than the dielectric constant of the first antenna. The method of claim 2, And a center frequency of the second antenna is located at an edge of a frequency band in which the built-in antenna can be received. According to claim 1, The first antenna and the second antenna spaced apart, the internal antenna, characterized in that less than 1mm. 6. The method of claim 5, The spacing between the first and the second antenna is a built-in antenna, characterized in that spaced apart on the three-axis coordinate system. According to claim 1, And the first antenna pattern and the second dielectric layer are branched about the same feed point. According to claim 1, And the first antenna and the second antenna are electromagnetically resonantly coupled. The method of claim 4 And the second antenna is positioned such that a center frequency is included within ± 20% of a frequency corresponding to a frequency band edge of the embedded antenna. In the built-in antenna, First and second antennas formed on dielectric layers having different dielectric constants, The proximity of the first antenna extends to the dielectric layer of the second antenna. The method of claim 10, And the second antenna comprises a dielectric layer having a higher dielectric constant than the first antenna. 12. The method of claim 11, And a center frequency of the second antenna is located at an edge of a frequency band to which the built-in antenna is to be received. In a portable communication terminal, A case; A first antenna having a first antenna pattern formed on the first dielectric layer, and a second antenna having a second antenna pattern formed on the second dielectric layer having a higher dielectric constant than the first dielectric layer; And a pattern extending to the second dielectric layer and including a built-in antenna mounted in the case. The method of claim 13, The second antenna has a higher Q value than the first antenna. The method of claim 13, The first and second antennas are spaced apart from each other by a portable communication terminal. The method of claim 15, The spaced interval between the first and the second antenna is a portable communication terminal, characterized in that spaced apart on the three-axis coordinate system The method of claim 13, And the second antenna has a higher dielectric constant than the first antenna. In a portable communication terminal, A first antenna having a first antenna pattern formed on the first dielectric layer, and a second antenna having a second antenna pattern formed on the second dielectric layer having a higher dielectric constant than the first dielectric layer; The pattern includes a built-in antenna extending to the second dielectric layer; Portable communication terminal comprising a case for mounting the built-in antenna. 19. The method of claim 18, And a center frequency of the second antenna is located at an edge of a frequency band in which the internal antenna can be received. In a portable communication terminal, A case; A first antenna including a first antenna pattern formed on the case; A second antenna having a second antenna pattern formed on a dielectric layer having a higher dielectric constant than the case; And the second antenna pattern extends to the dielectric layer. The method of claim 20, The first antenna pattern is a portable communication terminal, characterized in that attached to the outer wall or inner wall of the case in the form of a film. The method of claim 21, And the first antenna pattern is formed in the case to be embedded in the case by in-mold injection molding. The method of claim 20, The second antenna has a higher Q value than the first antenna. The method of claim 20, And the first antenna and the second antenna are electromagnetically resonantly coupled. The method of claim 20 And the second antenna is positioned such that a center frequency is included within ± 20% of a frequency corresponding to a frequency band edge of the embedded antenna. The method of claim 20, And the proximity point of the first antenna extends to the dielectric layer of the second antenna. The method of claim 20, The wireless communication terminal is a portable communication terminal, characterized in that the form of contact with the user's body, such as a wrist watch.

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