KR20110044576A - Embeded wide-band antenna using loop structure - Google Patents

Abstract

PURPOSE: A wideband internal antenna using a loop structure is provided to secure wideband characteristic by selectively adjusting a resonance point of each resonance mode in multi resonance. CONSTITUTION: A wideband internal antenna using a loop structure includes a carrier(200), a feeding point(202), a radiator(204), and a loop(206) formed on radiator. The loop formed on radiator transfers one resonance point among a resonance point at a resonance mode of multiple generated from the antenna. The loop is additionally formed in the radiator. The loop formed on radiator transfers the resonance point of a fundamental resonance mode.

Description

Embedded wide-band antenna using loop structure

The present invention relates to an antenna, and more particularly, to an embedded antenna capable of transmitting and receiving a wideband frequency signal.

Recently, a mobile terminal has been required to have a small size and a light weight, and to receive a mobile communication service having a different frequency band using a single terminal. For example, CDMA services in the 824-894 MHz band commercially available in Korea, PCS services in the 1750-1870 MHz band, CDMA services in the 832-925 MHz band commercially available in Japan, and the 1850-1990 MHz band commercially available in the US. Multi-band signal as needed among mobile communication services using various frequency bands such as PCS service, GSM service of 880 ~ 960 MHz band commercialized in Europe, China, and DCS service of 1710 ~ 1880 MHz band commercialized in some parts of Europe. There is a demand for a terminal capable of simultaneously using the antenna, and an antenna having a wideband characteristic is required for accommodating such multiple bands.

 However, as the research results show that the bandwidth decreases as the size of the antenna decreases, the demand for antenna miniaturization and the demand for broadband characteristics have a mutual relationship, and various studies have been tried to overcome this problem.

 Typical antennas for mobile terminals are mainly implemented in the form of monopole or PIFA. Each type has advantages and disadvantages. In the case of monopole antennas, it is easy to obtain broadband characteristics depending on the structure, but the matching characteristics are deteriorated when the distance from the ground approaches for miniaturization. In addition, in case of PIFA, it is easy to improve the matching characteristics by using a ground pin, but it is difficult to obtain broadband characteristics. Therefore, various types of patterns have been tried to overcome these limitations while maintaining basic monopole and PIFA shapes, and techniques such as miniaturization using chip antennas and matching using concentrated elements have been applied. However, when miniaturization and wideband are implemented by using these methods, the radiation efficiency characteristics are generally degraded.

The present invention is to propose a broadband internal antenna using a loop structure that can increase the bandwidth without changing the basic size of the antenna.

Another object of the present invention is to propose a broadband internal antenna using a loop structure capable of realizing broadband characteristics by changing only the frequency of a specific resonance band among multiple resonance bands of the antenna.

Other objects of the present invention will be readily apparent to those skilled in the art through the following examples.

In order to achieve the above object, according to an aspect of the present invention, a radiator including at least one loop portion electrically connected to a part of the meander structure; And a feed unit configured to provide a feed signal to the radiator.

By the loop portion, the resonance point of the basic resonance mode is adjacent to the resonance point of the secondary resonance mode, thereby securing broadband characteristics.

The null point of the basic resonance mode is not present on the loop portion and at least one of the null points of the secondary resonance mode is present on the loop portion.

The resonance point of the basic resonance mode moves to a high frequency band as compared with the case where the loop portion is not formed, and the resonance point of the secondary resonance mode does not change compared with the case where the loop portion is not formed.

The loop portion is formed by electrically connecting both ends of the 'c' shaped meander structure.

According to another aspect of the invention, the carrier; A feed patch electrically coupled with a feed unit and coupled to the carrier; And a radiator coupled to the carrier and electrically spaced apart from the feed patch to receive a coupling feed and having at least one end connected to ground, wherein the radiator includes at least one loop portion electrically connecting a part of a meander structure. A broadband internal antenna using a loop structure is provided.

The feeding patch may be coupled to the lower portion of the carrier and the radiator may be coupled to the upper and lower portions of the carrier.

According to another aspect of the invention, the radiator comprising at least one loop portion is formed the shortest path and the bypass path; And there is provided a broadband internal antenna using a loop structure including a feeder for providing a feed signal to the radiator.

According to the present invention, according to the present invention, there is an advantage that the broadband point can be secured by selectively adjusting the resonance point of each resonance mode in the multiple resonance.

Hereinafter, with reference to the accompanying drawings will be described a preferred embodiment of a broadband internal antenna using a loop structure according to the present invention in detail.

1 is a view showing the structure of a built-in antenna having a conventional meander radiator.

Referring to FIG. 1, the built-in antenna having the conventional meander radiator illustrated in FIG. 1 includes a carrier 100, a feed point 102, and a radiator 104.

The carrier 100 is made of a dielectric material and functions as a body of the antenna.

The radiator 104 is formed on the carrier. 1 shows a meander shaped emitter 104 bent over a plurality. The radiator is made of a metal material, for example, a metal of copper material is used. The resonant frequency of the antenna is determined by the length of the radiator, and the meander shaped radiator is used to maximize the length of the radiator in a limited space.

One end of the radiator 104 is electrically connected to the feed point 102 to receive an RF signal.

In the antenna shown in FIG. 1, a loop radiator is shown in which one end of the radiator 104 is coupled to the feed contact 102 and the other end is coupled to ground.

In a general antenna as well as a loop antenna as shown in FIG. 1, a basic resonance band and a higher order resonance band are formed. Higher-order resonant bands and fundamental resonant bands generally have an integral multiple, but may vary depending on the type and mounting type of antenna.

In the built-in antenna as shown in FIG. 1, it is common to use only a basic resonance band for transmitting and receiving an RF signal, and a high order resonance band is rarely used.

2 is a diagram illustrating a structure of a broadband embedded antenna using a loop structure according to the first embodiment of the present invention.

2, the broadband internal antenna using the loop structure according to the first embodiment of the present invention includes a carrier 200, a feed point 202, a radiator 204, and a loop part 206 formed on the radiator. do.

The antenna according to the first embodiment of the present invention shown in FIG. 2 is a structure in which a loop 206 is formed by electrically connecting a part of the meander structure in the antenna of FIG. 1 having a meander emitter.

The antenna according to the first embodiment of the present invention shown in FIG. 2 is different from a general loop antenna in that a loop is formed in a part of the radiator, and compared to a general built-in antenna by additionally forming the loop part 206 in the radiator. It is possible to have broadband characteristics.

The loop unit 206 formed on the radiator moves the resonance point of any one of the resonance points in the multiple resonance modes generated in the antenna so that the antenna has a broadband characteristic. Specifically, the loop portion 206 formed on the radiator moves the resonance point of the basic resonance mode (the mode with the smallest resonant frequency) while not moving the resonance point of the higher-order resonance mode adjacent to the resonance point of the basic resonance mode. And the resonance point of the higher-order resonance mode are adjacent to each other, thereby ensuring the broadband characteristics.

Detailed description of the principle and conditions for securing the broadband characteristics by forming the loop portion 206 in the radiator will be described with reference to the separate drawings.

The roof portion 206 formed on a part of the radiator is preferably formed by connecting both ends of the "c" shaped meander in the radiator of the meander structure, and one loop part is illustrated in FIG. 2. However, it will be apparent to those skilled in the art that the number of loop portions may be plural.

FIG. 3 is a diagram illustrating current distribution and null points in a basic resonance mode in the built-in antenna having the conventional meander radiator illustrated in FIG. 1.

Referring to FIG. 3, in the basic resonance mode, one null point is formed and a current flow is formed around the null point.

FIG. 4 is a diagram illustrating current distribution and null points in the secondary resonance mode in the built-in antenna having the conventional meander radiator illustrated in FIG. 1.

4 shows null points and current distributions in the secondary resonance mode where the fundamental resonance point and the resonance point are adjacent to each other. As shown in FIG. 4, in the second resonance mode, two null points are formed. There are two current flows in which current is concentrated to null point 1 in relation to null point 1, and there are two current flows in which current starts from null point 2 in relation to null point 2.

In the antenna having the meander emitter shown in FIG. The point and current distribution will be discussed.

5 is a diagram illustrating current distribution and null points in a basic resonance mode in a broadband internal antenna using a loop structure according to the first embodiment of the present invention.

Referring to FIG. 5, the null point in the basic resonance mode of the antenna according to the first embodiment of the present invention is electrically connected to both ends of the meander portion as compared to the antenna illustrated in FIG. It can be seen that by moving to form.

By forming the loop portion in the radiator, the shortest path 500 and the bypass path 502 are formed in the radiator.

In FIG. 5, the current formed from the null point toward the feed point by connecting both ends of the 'c' shaped meander flows to the shortest path 500, and the bypass path 510 corresponding to the outer edge of the loop. Only a fairly weak current will flow.

As such, when the meander portion is connected to form a loop portion, the overall electrical length of the antenna in the basic resonance mode is reduced, and as a result, the null point is moved when compared to the antenna described with reference to FIG. 3. Due to the movement of the null point, the fundamental resonant frequency changes, and the reduced electrical length changes the fundamental resonant frequency to a higher frequency.

At this time, in order for the fundamental resonance frequency to rise to a higher frequency, the null point before connecting the both ends of the meander to form the loop part should not exist in the meander, and even after the loop part is formed, the null point is present on the loop part. No.

FIG. 6 is a diagram illustrating current distribution and null points in a secondary resonance mode in a broadband internal antenna using a loop structure according to the first embodiment of the present invention.

Referring to FIG. 6, two null points exist in the second resonance mode, and the position of the null point is not significantly changed as compared with FIG. 4, which is a structure before connecting both ends of the meander to form a loop.

As described above, the case where the loops are formed by connecting both ends of the meander portion in the second resonant mode and the position of the null point hardly changes in the other case is connected to both ends of the meander so that the new shortest path 600 is formed. Even if it is formed, most of the current still flows in the outer portion of the loop (meander portion 610 before loop formation).

In addition, even though the new path 600 is formed as described above, current flows in the existing path 610 because at least one of the existing null points is present on the loop portion 206.

Referring to FIG. 4, among the null points in the second resonance mode before forming the loop part, null point 1 exists on the loop part when forming a loop. Therefore, even if both ends of the meander are connected to form a loop, since the reference point of current formation exists on the loop, there is almost no current flow in the newly formed path 600, and most of the current is in the existing bypass path 610. As it passes, the position of the null point hardly changes.

As described above, the fact that the position of the null point does not change in the second resonance mode means that the position of the resonance point does not change. That is, according to the antenna according to the first embodiment of the present invention, the resonance point in the basic resonance mode is changed, but the resonance point in the higher-order resonance mode can be maintained as it is, so that the resonance point can be individually adjusted in the multiple resonance mode.

The selective resonance point control of the multiple resonance mode in the antenna in which the loop structure of the present invention is applied to the radiator can be effectively used to secure the broadband characteristics. That is, by adjusting the resonance point of the basic resonance mode closer to the resonance point of the higher-order resonance mode, it is possible to secure the broadband characteristics.

In addition, when adjusting the position of the loop while maintaining the conditions regarding the null point and the loop, the interval between the basic resonance mode and the secondary resonance mode may be adjusted, and thus the bandwidth may be adjusted.

FIG. 7 is a graph comparing return loss of the antenna shown in FIG. 1 and the antenna shown in FIG. 2.

Referring to FIG. 7, the antenna shown in FIG. 1 has a fundamental mode resonance point and a higher-order mode resonance point spaced apart from each other, and each resonance point has a narrow band characteristic, but the antenna according to the first embodiment of the present invention shown in FIG. As the fundamental resonance point moves closer to the higher-order mode resonance point, it can be seen that broadband characteristics are secured.

In the above, the case where the loop structure of the present invention is applied to a loop antenna having a meander radiator has been described, but the idea of the present invention, which secures broadband characteristics by applying the loop structure to the radiator, may be applied to various kinds of antennas. For example, the loop structure of the present invention may be applied to a radiator of various kinds of antennas such as a monopole antenna, a PIFA antenna, a dipole antenna, and a microstrip patch antenna to be used to secure broadband characteristics.

Among the loop structures of the present invention that can be applied to various antennas, a second embodiment of the present invention will be described.

8 is a diagram illustrating an antenna using a coupling feed according to an embodiment of the present invention.

Referring to FIG. 8, an antenna using a coupling feed according to an embodiment of the present invention includes a carrier 800, a feeder 802, a feed patch 804, a radiator 806, and a ground plate 808. can do.

In FIG. 8, the carrier 800 is made of a dielectric material and functions as a body to which the feed patch 804 and the radiator 806 are coupled.

The feeder 802 is a portion in which the RF signal is fed, and the RF signal may be fed through the transmission line. As the transmission line, for example, a coaxial cable or the like may be used. In addition, various known transmission lines such as a micro strip line may be used.

The feed patch 804 is electrically coupled to the feed 802 and is coupled to the bottom of the carrier 800. FIG. 8 illustrates a square feed patch, but the shape of the feed patch may be variously changed.

The feed patch 804 performs a coupling feed function to the radiator 806, and the size of the feed patch for proper feeding and the positional relationship with the radiator may vary depending on the frequency band used and the mounting environment.

Both ends of the radiator 806 are electrically connected to the ground plate 808. Only one end of the radiator 806 may be electrically connected to the ground plate 808, and both ends of the radiator 806 may be connected to the ground plate 808 as shown in FIG. 8. If both ends of the radiator are connected to ground, the radiator acts as a loop radiator.

As shown in FIG. 8, the radiator 806 is coupled to both the bottom and top surfaces of the carrier for efficient space utilization. In addition, the radiator 806 is a meander shape bent over a plurality.

The antenna according to the embodiment of the present invention shown in FIG. 8 can obtain relatively broadband characteristics through coupling feeding of the feeding patch in the lower part of the carrier, and when a wider range of broadband characteristics is required, the above-described loop structure Can be applied.

9 is a diagram illustrating a structure of a broadband internal antenna using a loop structure according to a second embodiment of the present invention.

9, the broadband internal antenna using the loop structure according to the second embodiment of the present invention includes a carrier 900, a feed point 902, a feed patch 904, a radiator 906, and a ground plate 908. And a loop portion 910.

The antenna according to the second embodiment of the present invention illustrated in FIG. 9 is a structure in which a loop part 910 is formed by electrically connecting a part of the meander structure in the antenna of FIG. 8 having a meander emitter.

In the radiator 806 of the antenna shown in FIG. 8, the null point of the basic resonance mode is not present in the meander portion, and at least one of the two null points of the secondary resonance mode is present in the meander portion.

This means that in the antenna shown in FIG. 9, the null point of the basic resonance mode exists on the loop portion 910, but at least one of the two null points of the second resonance mode exists on the loop portion 910. .

As illustrated in FIG. 9, when the loop portion is formed by connecting both ends of the 'c'-shaped meander, the resonance point of the basic resonance mode and the resonance point of the secondary resonance mode are closer to each other. When the null point of the basic resonance mode does not exist on the loop portion 910 and at least one of the null points of the higher-order resonance mode including the secondary resonance mode exists on the loop portion, a new connected point is formed when forming the loop portion in the basic resonance mode. Compared to the movement of the fundamental resonance point by the path, there is no movement of the resonance point in the higher-order resonance mode, so that the resonance point between the basic resonance point and the higher-order resonance mode is closer to each other, and thus has a broadband characteristic.

1 is a view showing the structure of a built-in antenna having a conventional meander emitter

2 is a diagram illustrating a structure of a broadband internal antenna using a loop structure according to the first embodiment of the present invention.

3 is a diagram illustrating current distribution and null points in a basic resonant mode in the built-in antenna with the conventional meander emitter shown in FIG.

4 is a diagram illustrating current distribution and null points in the secondary resonance mode in the built-in antenna having the conventional meander radiator shown in FIG.

5 is a diagram illustrating current distribution and null points in a basic resonance mode in a broadband internal antenna using a loop structure according to the first embodiment of the present invention.

FIG. 6 is a diagram illustrating current distribution and null points in a secondary resonance mode in a broadband internal antenna using a loop structure according to the first embodiment of the present invention.

7 is a graph comparing return loss of the antenna shown in FIG. 1 and the antenna shown in FIG.

8 illustrates an antenna using a coupling feed according to an embodiment of the present invention.

9 is a diagram illustrating a structure of a broadband internal antenna using a loop structure according to a second embodiment of the present invention.

Claims (12)

A radiator comprising at least one loop portion electrically connecting a portion of the meander structure; And And a feeder configured to provide a feed signal to the radiator. The method of claim 1, And a wide band characteristic is secured by the loop unit to ensure that the resonance point of the basic resonance mode is adjacent to the resonance point of the secondary resonance mode. The method of claim 1, And a null point of a basic resonance mode does not exist on the loop portion, and at least one of the null points of a secondary resonance mode exists on the loop portion. The method of claim 3, The resonance point of the basic resonance mode is moved to a high frequency band compared with the case where the loop portion is not formed, and the resonance point of the secondary resonance mode does not change compared to the case where the loop portion is not formed. Broadband built-in antenna using The method of claim 1, The loop portion is a broadband internal antenna using a loop structure, characterized in that formed by electrically connecting both ends of the 'c' shaped meander structure. carrier; A feed patch electrically coupled with a feed unit and coupled to the carrier; And A radiator coupled to the carrier and electrically spaced apart from the feeding patch to receive a coupling feed and having at least one end connected to ground; The radiator is a broadband internal antenna using a loop structure, characterized in that it comprises at least one loop portion electrically connected to a part of the meander structure. The method of claim 6, The feed patch is coupled to the lower portion of the carrier and the radiator is coupled to the upper and lower portions of the carrier broadband internal antenna using a loop structure. The method of claim 6, And a null point of a basic resonance mode does not exist on the loop portion, and at least one of the null points of a secondary resonance mode exists on the loop portion. The method of claim 8, The null point of the basic resonance mode is shifted to the high frequency band when the resonance point of the basic resonance mode is not formed, and the resonance point of the secondary resonance mode is not changed compared to the case where the loop part is not formed. Broadband built-in antenna using a loop structure, characterized in that not. 10. The method of claim 9, The loop portion is a broadband internal antenna using a loop structure, characterized in that formed by electrically connecting both ends of the 'c' shaped meander structure. A radiator comprising at least one loop portion in which a shortest path and a bypass path are formed; And And a feeder configured to provide a feed signal to the radiator. The method of claim 11, And a null point of a basic resonance mode does not exist on the loop portion, and at least one of the null points of a secondary resonance mode exists on the loop portion.

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