KR100536743B1 - An antenna for mobile communication terminal - Google Patents

Abstract

The present invention relates to an antenna for a mobile communication terminal, comprising a radiating part and a feeding part on a single printed circuit board, forming the radiating part in a microstrip structure in the form of a printed loop, and feeding the radiating part on the same plane as the ground part. It is made of coplanar waveguide structure to be installed. The present invention can be further miniaturized due to the structure in which the radiating part and the feeding part are installed on a single printed circuit board, and is easy to be embedded in the terminal, while the feeding part is manufactured in the coplanar waveguide structure, which is very ideal and good. It exhibits radiation characteristics and thus has a wider bandwidth characteristic.

Description

Antenna for mobile communication terminal {An antenna for mobile communication terminal}

The present invention relates to an antenna for a mobile communication terminal, and more particularly, to an antenna for a mobile communication terminal, which is easy to be incorporated into a terminal in an ultra-thin flat plate form and exhibits excellent radiation characteristics.

As is well known, in order to provide high quality service in response to the rapid increase in the demand for mobile communication, the development of the antenna belonging to the core parts among the communication equipment has become an important issue. In other words, the antenna attached to the base station or the terminal is an important factor in determining the call quality. As the size and integration of the mobile communication terminal are reduced, the antenna is also required to have small size, light weight, multi-function characteristics, and mass production characteristics.

Antennas currently used in mobile communication terminals include monopole antennas, helical antennas, and patch antennas.

The monopole antenna and the helical antenna are most widely used for a mobile communication terminal. However, the monopole antenna and the helical antenna are disadvantageous in that they are inconvenient to carry and frequently damaged due to protruding from the outside of the terminal due to the installation structure. There is a disadvantage that the structure can not meet the recent consumer tastes that require a variety of designs.

The patch antenna is an antenna formed as a micro strip line on a printed circuit board. The patch antenna is easy to be built in a terminal, is easy to manufacture, and is suitable for mass production, but has a bandwidth of several% due to the characteristics of the micro strip line. It is very narrow, so it is not easy to apply, and because the patch length is about 1/2 of the resonant frequency wavelength (λ), the antenna is too large to be used in the low frequency band. There are disadvantages that follow.

Accordingly, the present invention has been made to solve the above-mentioned problems of the prior art, and provides an antenna for a mobile communication terminal that is easy to design, can be used in a low frequency band, and can have a wideband characteristic. Its purpose is to.

An antenna for a mobile communication terminal according to the present invention for achieving the above object is a pattern formed on a printed circuit board with a long loop portion of the radiating portion and the feeding portion to one side of the radiating portion in the longitudinal direction of both sides of the feeding portion The side by side is spaced apart by a predetermined gap to form a ground portion, characterized in that for controlling the maximum resonance point and bandwidth by adjusting the distance between the radiating portion and the ground portion.

In addition, the present invention, the horizontal outer side length of the radiating part is about 33 [mm], the longitudinal outer side length of the radiating part is about 18 [mm], the horizontal inner side length of the radiating part is about 23 [mm], the radiation The length of the inner side of the part is about 12 [mm], the distance between the radiating part and the ground part is about 1 [mm], and the distance between the feeding part and the ground part is about 0.8 [mm]. It features.

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

1 (a) and (b) are a plan view and a side view showing a schematic structure of an antenna for a mobile communication terminal according to a preferred embodiment of the present invention, respectively, as can be seen with reference to the drawings, the movement according to the present invention An antenna for a communication terminal has a square loop-shaped radiating part 2 and a feeding part 3 formed on one side of the radiating part 2 on a printed circuit board 1 with a long pattern, and both sides of the feeding part 3. And the ground portions 4 and 5 are patterned to be spaced apart by a predetermined gap along the longitudinal direction. However, the conductor pattern is not formed in the rear portion of the printed circuit board 1.

Here, the transverse outer length W1 of the radiating section 2 is set within a range of approximately " λ / 2 to λ / 4 " with respect to the operating frequency λ.

In the antenna for mobile communication of the present invention, the power supply unit 3 and the grounding units 4 and 5 are provided on the same plane of the printed circuit board 1 to form a waveguide, so-called coplanar waveguides. (Coplanar Waveguide; "CPW") structure.

The feeding method of the coplanar waveguide structure can suppress the radiation from the feeding part as much as possible, compared to the conventional feeding method using the waveguide of the microstrip structure. It will be described in more detail with reference to the drawings below.

In addition, since the radiating part 2 is manufactured in the form of a square loop, the radiating part 2 exhibits relatively excellent radiating characteristics compared to a conventional patch type, and the length of the radiating part 2 is sufficiently limited even in a low frequency band while being relatively less restricted by the design due to the loop shape. Can be.

Further, by adjusting the length of the radiating section 2 and the distance h between the radiating section 2 and the ground sections 4 and 5, it is possible to adjust the antenna characteristics such as the bandwidth and the maximum resonance point.

For example, in the antenna for a mobile communication terminal of the present invention configured as described above, as shown in Table 1 below, the horizontal outer side length W1 of the radiator 2 is approximately 33 [mm], and the radiator is The longitudinal outer edge length of the radiator 2 is approximately 18 [mm], the transverse inner edge length W2 of the radiator 2 is approximately 23 [mm], and the longitudinal inner edge length of the radiator 2 is approximately 2 [mm]. Is about 12 [mm], the spacing h between the radiating section 2 and the ground sections 4 and 5 is about 1 [mm], and between the feed section 3 and the ground sections 4 and 5 The gap g may be manufactured to about 0.8 [mm]. In addition, the substrate may be manufactured to have a dielectric constant (ε _r ) of 4.6 and a thickness of 1.6 [mm].

TABLE 1

Parameter length [mm] ℓ1 18 ℓ2 12 W1 33 W2 23 h One g 0.8

 Table 1 is a dimension designed to be applied to both the frequency band (1.75 ~ 1.87 GHz) of the PCS (Personal Communication System) and the frequency band (1.92 ~ 2.17 GHz) of the IMT2000, the best radiation characteristics by the actual measurement results The result is found and applied.

Hereinafter, with reference to the accompanying drawings will be described for the actual effect of the present invention as described above.

FIG. 2 is a diagram illustrating a comparison between a simulation result and a measurement result of the reflection coefficient of the antenna for the mobile communication terminal shown in FIG. 1. As shown in the drawing, the simulation result and the measurement result of the reflection coefficient are very high. The approximate and measured reflection coefficient is very good.

FIG. 3 is a view showing comparisons between reflection coefficients when the antenna for the mobile communication terminal shown in FIG. 1 is mounted on an actual mobile communication terminal and when it is not mounted. As shown in FIG. It can be seen that the reflection coefficients between the case where the antenna for the mobile communication terminal is mounted on the actual mobile communication terminal and when the antenna for the mobile communication terminal are not mounted coincide with each other.

FIG. 4 is a Smith chart illustrating a change in input impedance according to a change in a distance h between the radiating part and the ground part in FIG. 1.

In the antenna for a mobile communication terminal of the present invention, since the radiating part 2 and the feeding part 3 are installed on a single plane, the maximum resonance point depends on the change of the distance h between the ground parts 4 and 5 and the radiating part 2. Since and the frequency band is different, the results of the change in the interval (h) was examined by the Smith chart.

Referring to FIG. 4, as the distance h between the ground parts 4 and 5 and the radiator 2 increases, the band increases, but the reflection coefficient also increases.

Therefore, in consideration of the relationship between the frequency band and the reflection coefficient, it can be seen that the optimum value of the distance h between the ground portions 4 and 5 and the radiating portion 2 is about 1 [mm].

FIG. 5 is a diagram illustrating a measurement radiation pattern of an electric field with respect to the XZ plane (Φ = 0) of the antenna for the mobile communication terminal shown in FIG. 1, and FIG. 6 is a YZ plane of the antenna for the mobile communication terminal shown in FIG. FIG. 7 is a diagram illustrating a measurement radiation pattern of an electric field for Φ = 90, and FIG. 7 illustrates the electric field of the electric field with respect to the XZ plane (Φ = 0) in a state in which the antenna for the mobile communication terminal shown in FIG. FIG. 8 is a diagram illustrating a measurement radiation pattern, and FIG. 8 is a diagram illustrating a measurement radiation pattern of an electric field on the YZ plane (Φ = 90) when the antenna for the mobile communication terminal illustrated in FIG. 1 is mounted on an actual mobile communication terminal.

9 is a view showing a measurement radiation pattern of the magnetic field for the antenna for the mobile communication terminal shown in FIG. 1, FIG. 10 is a state in which the antenna for the mobile communication terminal shown in FIG. It is a figure which shows the measurement radiation pattern of a magnetic field.

5 to 10, it can be seen that the antenna for the mobile communication terminal according to the present invention has a very good measurement radiation pattern of the magnetic field and the electric field. In particular, the measured radiation patterns of the magnetic field and the electric field approximated the omnidirectional radiation patterns, which showed very ideal results.

In addition, in the antenna for a mobile communication terminal according to the present invention, the antenna gain is approximately 2.67 [dBi] as a result of the measurement, and the frequency bandwidth is calculated based on VSWR ≥ 1.5, resulting in 100 Mhz (1.68-1.87 [Ghz]) bandwidth. As a result of the actual measurement, the bandwidth of 114Mhz (1.46∼2.6 [Ghz] is obtained, which is very broadband compared to the patch antenna, which is PCS frequency band (approximately 1.75∼1.87 [Ghz]) and IMT2000 frequency band (approximately 1.92). ~ 2.17 [Ghz]) can be satisfied simultaneously.

As described above, the present invention has a coplanar waveguide structure in which a radiating part and a feeding part are installed on a single printed circuit board, the radiating part is formed in the form of a printed loop, and the feeding part is installed on the same plane as the ground part. It is produced.

The present invention can be further miniaturized due to the structure in which the radiating part and the feeding part are installed on a single printed circuit board, and is easy to be embedded in the terminal, while the feeding part is manufactured in the coplanar waveguide structure, which is very ideal and good. Since the radiation characteristics are exhibited, there is an effect that the characteristics of the broadband may be more wide. In particular, the present invention can satisfy the PCS frequency band (approximately 1.75-1.87 [Ghz]) and the IMT2000 frequency band (approximately 1.92-2.17 [Ghz]) at the same time to cover various frequency bands of next-generation mobile communication terminals with a single antenna. can do.

In addition, the present invention is easy to design and suitable for incorporation into a small mobile communication terminal according to the relatively small constraints in extending the length of the antenna in the low frequency band as the radiator is a loop type.

1 (a) and (b) are a plan view and a side view showing a schematic structure of an antenna for a mobile communication terminal according to a preferred embodiment of the present invention, respectively;

FIG. 2 is a view showing comparison results of simulation results and measurement results of the reflection coefficient of the antenna for the mobile communication terminal shown in FIG. 1;

3 is a view illustrating comparison of reflection coefficients with and without the antenna for the mobile communication terminal shown in FIG.

FIG. 4 is a Smith chart illustrating a change in input impedance according to a change in a distance h between the radiator and the ground in FIG. 1;

FIG. 5 is a view showing a measurement radiation pattern of an electric field on the X-Z plane (Φ = 0) of the antenna for a mobile communication terminal shown in FIG. 1;

FIG. 6 is a view showing a measurement radiation pattern of an electric field on the Y-Z plane (Φ = 90) of the antenna for a mobile communication terminal shown in FIG. 1;

FIG. 7 is a diagram illustrating a measurement radiation pattern of an electric field on an X-Z plane (Φ = 0) in a state in which an antenna for a mobile communication terminal shown in FIG.

8 is a view showing a measurement radiation pattern of the electric field on the Y-Z plane (Φ = 90) in the state that the antenna for the mobile communication terminal shown in FIG.

9 is a view showing a measurement radiation pattern of the magnetic field for the antenna for the mobile communication terminal shown in FIG.

FIG. 10 is a diagram illustrating a measurement radiation pattern of a magnetic field in a state in which an antenna for a mobile communication terminal shown in FIG. 1 is mounted on an actual mobile communication terminal.

<Explanation of symbols for main parts of the drawings>

1: printed circuit board 2: radiator

3: feed part 4, 5: ground part

Claims (5)

In the antenna for a mobile communication terminal, It is made by forming a pattern on the printed circuit board with a square loop-shaped radiating part and a feeding part to the one side of the radiating part long and spaced apart by a predetermined gap side by side along the longitudinal direction to both sides of the feeding part. The antenna for the mobile communication terminal, characterized in that for controlling the maximum resonance point and the bandwidth by adjusting the interval between the four parts and the ground. An antenna for a mobile communication terminal according to claim 1, wherein the horizontal outer side length of said radiating portion is within a range of " λ / 2 to λ / 4 " with respect to an operating frequency [lambda]. 3. An antenna for a mobile communication terminal according to claim 2, wherein said operating frequency is approximately 1.75-1.87 GHz band. The antenna for a mobile communication terminal according to claim 2, wherein the operating frequency is in a band of about 1.92 to 2.17 GHz. The antenna of claim 1, wherein the antenna has a horizontal outer side length of about 33 [mm], a longitudinal outer side length of about 18 [mm], and a horizontal inner side length of the radiating part. About 23 [mm], the length of the inner side of the radiating part is about 12 [mm], the spacing between the radiating part and the ground part is about 1 [mm], and the spacing between the feeding part and the ground part is about An antenna for a mobile communication terminal, characterized in that about 0.8 [mm].