KR100951582B1 - Ultra Wide Band Diversity Antenna - Google Patents

Abstract

The present invention relates to an ultra-wideband diversity antenna. The present invention is a substrate having a predetermined dielectric constant; A ground plate formed of a conductor in a predetermined region of the substrate; A plurality of radiators on the substrate, spaced apart from the ground plate to transmit and receive an RF signal, each of the plurality of radiators spaced apart from each other; A plurality of feed lines for feeding the plurality of radiators; And at least one stub disposed coplanar with the plurality of radiators on the substrate to isolate each radiator. According to the present invention, it is possible to provide an antenna having broadband characteristics and excellent isolation characteristics.

Diversity, Antennas, Radiators, Stubs, Feeding, Ultra Wideband, Wireless LAN

Description

Ultra Wide Band Diversity Antenna

The present invention relates to an ultra-wideband diversity antenna, and more particularly, to an antenna for a mobile communication terminal capable of providing various services.

Currently, mobile communication terminals are required to have various service providing functions while being miniaturized and lightweight. In order to satisfy these demands, embedded circuits and components employed in mobile communication terminals are becoming more versatile and at the same time gradually becoming smaller. This trend is equally required in the antenna, which is one of the main components of the mobile communication terminal.

As the mobile communication service is diversified as described above, the necessity of a broadband terminal capable of providing a plurality of services is increasing, and a diversity antenna is provided in a corresponding manner.

In providing various services, in a mobile communication environment, a multipath phenomenon occurs due to reflected waves caused by buildings or terrain on a path, and thus a fading phenomenon occurs in which amplitude of a received signal is changed. In order to alleviate such fading and maintain a desired transmission quality, a plurality of antennas are used. Such antennas are called diversity antennas.

On the other hand, research is being conducted to increase transmission reliability through diversity gain by configuring multiple transmit / receive antennas and to increase channel capacity through a spatial multiplexing technique. In addition, it is expected to solve the limitations of existing wireless communication standards such as high-speed data processing, and research on MIMO (Multiple-In Multiple-Out) technology capable of processing large data at high speed is being conducted.

MIMO is a technology that can transmit data at a higher speed than using one antenna without increasing the frequency bandwidth by using multiple antennas.

As such, MIMO technology using diversity antennas has been proposed to provide high data throughput in short-range wireless communication technology.

The most commonly used short-range wireless communication technology is a wireless local area network (WLAN). The wireless LAN method has developed from 802.11b (up to 11Mbps) to 802.11a, 802.11g, etc. to solve problems in data throughput, usage coverage, and frequency interference. Recently, the 802.11n method has been standardized, which is about 2 to 4 times higher than that of 802.11b and 802.11g in terms of high data throughput. 802.11n can handle more than 100 Mbps of data. What makes this possible is the Multi-In Multi-Out (MIMO) technology.

However, the band of the antenna system for applying MIMO technology is currently limited to the development of an antenna for one service such as WLAN, WiMAX band.

When a large number of antennas are simply provided in a narrow area of a mobile communication terminal for high data throughput, a problem arises in that isolation characteristics between antennas are deteriorated. Therefore, it is essential to develop a broadband MIMO antenna technology that includes a plurality of services and has improved isolation characteristics.

In the present invention, in order to solve the problems of the prior art as described above, it is proposed a diversity antenna having an ultra-wideband characteristics and can obtain improved isolation characteristics.

Another object of the present invention is to provide a diversity antenna that can be provided in a narrow area such as a mobile communication terminal.

According to a preferred embodiment of the present invention to achieve the above object, a substrate having a predetermined dielectric constant; A ground plate formed of a conductor in a predetermined region of the substrate; A plurality of radiators on the substrate, spaced apart from the ground plate to transmit and receive an RF signal, each of the plurality of radiators spaced apart from each other; A plurality of feed lines for feeding the plurality of radiators; And at least one stub disposed coplanar with the plurality of radiators on the substrate to isolate each radiator.

According to another aspect of the invention, a substrate having a predetermined dielectric constant; A ground plate formed of a conductor on the substrate; A plurality of radiators spaced apart from one side of the ground plate to transmit and receive an RF signal; A plurality of feed lines for supplying current to the plurality of radiators; And one or more stubs disposed between the plurality of radiators to isolate each radiator.

According to the present invention, by providing one or more stubs between a plurality of radiators of a predetermined type, there is an advantage in that the isolation characteristics can be improved while configuring a diversity antenna in a narrow area.

In addition, according to the present invention provides a Y-shaped copy, there is an advantage that the impedance matching can be adjusted by adjusting the length of the copy.

Furthermore, according to the present invention, there is an advantage that can be mass-produced at low cost by using a general-purpose substrate.

As the invention allows for various changes and numerous embodiments, particular embodiments will be illustrated in the drawings and described in detail in the written description. However, this is not intended to limit the present invention to specific embodiments, it should be understood to include all modifications, equivalents, and substitutes included in the spirit and scope of the present invention. Like reference numerals are used for like elements in describing each drawing.

When a component is referred to as being "connected" or "connected" to another component, it may be directly connected to or connected to that other component, but it may be understood that other components may be present in between. Should be. On the other hand, when a component is said to be "directly connected" or "directly connected" to another component, it should be understood that there is no other component in between.

The terminology used herein is for the purpose of describing particular example embodiments only and is not intended to be limiting of the present invention. Singular expressions include plural expressions unless the context clearly indicates otherwise. In this application, the terms "comprise" or "have" are intended to indicate that there is a feature, number, step, operation, component, part, or combination thereof described in the specification, and one or more other features. It is to be understood that the present invention does not exclude the possibility of the presence or the addition of numbers, steps, operations, components, components, or a combination thereof.

Unless defined otherwise, all terms used herein, including technical or scientific terms, have the same meaning as commonly understood by one of ordinary skill in the art. Terms such as those defined in the commonly used dictionaries should be construed as having meanings consistent with the meanings in the context of the related art and shall not be construed in ideal or excessively formal meanings unless expressly defined in this application. Do not.

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings. In order to facilitate a thorough understanding of the present invention, the same reference numerals are used for the same means regardless of the number of the drawings.

1 is a diagram illustrating a diversity antenna according to an exemplary embodiment of the present invention.

As shown in FIG. 1, an antenna according to the present invention includes a substrate 10, a ground plate 11, a plurality of radiators 12, 13, feed lines 14, 15, and stubs 16, 17, 18. It may include.

The substrate 10 has a predetermined dielectric constant and corresponds to a medium of the RF signal.

Preferably, the substrate 10 according to the present invention may be a glass epoxy substrate FR-4, which has a dielectric constant _r of 4.4 and a height of 1.6 mm.

By using the FR-4 substrate, the antenna according to the present invention can be mass produced at low cost.

Meanwhile, the ground plate 11 is formed in a predetermined region of at least one surface of the substrate 10. The ground plate 11 may be composed of a rectangular conductor on the upper surface of the substrate 10 and provide an electrical ground.

The overall size of the antenna including the ground plate 11 according to the present invention may be provided in a size of 60mm × 80mm × 1.6mm.

According to one preferred embodiment of the present invention there is provided a plurality of radiators 12, 13 spaced apart from the ground plate 11.

An antenna according to the present invention is a diversity antenna having a plurality of radiators 12 and 13 for transmitting and receiving RF signals of a predetermined band independently to provide various services in a mobile communication terminal.

In general, while the signal radiated through the antenna of the mobile communication terminal propagates through the air, attenuation occurs due to geographical obstacles such as buildings and houses. Signals reflected and diffracted by these obstacles propagate through several paths instead of one.

This multipath signal causes multipath fading to increase and decrease in amplitude of the transmission / reception signal in the mobile communication terminal. This multipath fading reduces the stability of the wireless network. Is provided.

In general, the diversity scheme includes a site diversity scheme, a spatial diversity scheme, a polarization diversity scheme, a time diversity scheme, and a frequency diversity scheme.

Dual space diversity is a method of space-taking two antennas, and a technique for causing signals transmitted and received by antennas spaced apart from each other to have different phase shifts to have low correlation characteristics.

According to the present invention, the plurality of radiators 12 and 13 are provided to be spaced apart from each other, and the first radiator 12 spaced apart from one side of the ground plate 11 and the agent spaced from the other side of the ground plate 11 It may include two copies (13).

In this case, the first radiator 12 and the second radiator 13 may be formed by patterning on the same plane on the substrate 10 and may be formed of a conductor extending in a direction protruding from the ground plate 11. have.

However, those skilled in the art will understand that not only the case where the first radiator 12 and the second radiator 13 are formed on one surface of the substrate 10 but also the one spaced apart from the substrate 10 may be included in the scope of the present invention. Should.

In general, the length and shape of the radiator is an important factor in determining the bandwidth of the antenna. According to a preferred embodiment of the present invention, the plurality of radiators 12 and 12 may be applicable to a wireless LAN and an ultra wide band (UWB). 13) may have a Y-shape and the length is adjusted to have radiation characteristics in the desired band.

Here, the ultra-wideband wireless communication technology is a wireless communication technology utilizing a high frequency band of 2 to 10GHz.

By adjusting the length of the first radiator 12 and the second radiator 13, it is possible to adjust the impedance bandwidth and the resonant frequency of the desired band.

On the other hand, a power supply line such as a coaxial cable is inserted into one end of the first radiator 12 and the second radiator 13 according to the present invention, and the first power supply for supplying electricity to each of the radiators 12 and 13. Line 14 and second feed line 15 are provided.

The diversity antenna according to the present invention may be provided in a small device such as a mobile communication terminal. In this case, when the first and second radiators 12 and 13 are spaced apart from each other, Isolation characteristics are important.

To this end, according to one preferred embodiment of the present invention, one or more stubs 16 to 18 are provided between the first and second copies 12, 13.

The stubs 16 to 18 according to the present invention are connected to one side of the ground plate 11 and may be formed on the same plane as the first and second radiators 12 and 13.

According to the present invention, the isolation characteristics of the first and second radiators 12 and 13 may be adjusted by changing the length and number of stubs in the wireless LAN (WLAN, 802.11b) and the ultra wide band. .

Preferably, the stub according to the present invention includes a first stub 16 disposed adjacent to the first radiator 12 and a second stub 17 and first stub disposed adjacent to the second radiator 13. The third stub 18 may be disposed between the second stubs 17.

According to the present invention, by constructing a plurality of stubs (16 to 18) between the radiators 12 and 13, it is not necessary to have enough space to improve the isolation characteristics of the two radiators, thereby miniaturizing the antenna. .

In this case, the first and second radiators 12 and 13 are symmetrically disposed on at least one of the plurality of stubs described above, preferably the third stub 18 so as to secure a bandwidth suitable for ultra-wideband communication.

In addition, each stub 16 to 18 may be formed in a direction parallel to the extending direction of the first and second radiators 12 and 13.

In this case, the lengths of the first and second stubs 16 and 17 may be longer than those of the third stub 18.

In order to increase the isolation performance, the stubs 16 to 18 according to the invention can be formed in polygons, preferably in quadrangles. At this time, the end of the first stub 16 is bent to the first copy 12 side, the end of the second stub 187 is bent to the second copy 13 side.

According to the present invention, the first and second stubs 16 and 17 affect the isolation characteristics of the low and high bands of the operating frequency, and the third stub 18 affects the isolation characteristics of the intermediate band.

According to the present invention, the length and number of stubs are determined as an optimized result through simulation of the current flow in the S-parameter, the ground plane, and through each of the one or more stubs provided in a predetermined number and length between the radiators. It is possible to improve the isolation properties of the copy.

FIG. 2 is a diagram illustrating S-parameters for an ultra-wideband diversity antenna having a Y-shaped copy and three stubs according to the present invention.

Here, the S-parameter is an index indicating the voltage ratio between the input and the output in the frequency domain.

As shown in FIG. 2, the ultra-wideband diversity antenna according to the present invention has a reflection loss of 10 dB or less in a WLAN and an ultra-wideband.

Meanwhile, FIGS. 3 to 4 are diagrams showing simulation results of current flow in the radiator and the ground plate according to the present invention.

FIG. 3 shows the radiators 12 and 13 and the ground plate 11 according to the presence or absence of the stub at 5 GHz and 8 GHz with the power supplied to the first radiator 12 and the second radiator 13 terminated at 50 kHz. Indicates the current distribution.

Referring to FIG. 3A, it can be seen that the current distribution is similar to the first and second radiators 12 and 13 in the absence of the stub, and is shown in FIG. 3B when the stub is inserted into the ground plate 11. As can be seen, the distribution of current changes, and it can be seen that the isolation characteristics between the two radiators 12 and 13 are improved.

FIG. 4 shows the radiators 12 and 13 and the ground plate 11 according to the presence or absence of the stub at 5 GHz and 8 GHz, with the second radiator 13 feeding power and terminating the first radiator 12 at 50 kHz. The distribution of the current is shown.

Referring to FIG. 4A, it can be seen that the current distribution is similar to the first and second radiators 12 and 13 in the absence of the stub, and is shown in FIG. 4B when the stub is inserted into the ground plate 11. As can be seen, the distribution of current changes, and it can be seen that the isolation characteristics between the two radiators 12 and 13 are improved.

As noted above, the first and second stubs 16 and 17 affect the isolation characteristics of the low and high bands of the operating frequency, while the third stubs 18 are important to influence the isolation characteristics of the intermediate bands. To be an element.

5 is a diagram illustrating a radiation pattern of an ultra-wideband diversity antenna having a Y-shaped radiator and a stub according to the present invention.

5A to 5C, the ultra-wideband diversity antenna according to the present invention at 2.4 GHz, 5 GHz, and 8 GHz, respectively, exhibits a radiation pattern similar to that shown in the monopole antenna. That is, the ultra-wideband antenna according to the present invention forms an omnidirectional radiation pattern.

On the other hand, Figure 6 is a diagram showing the gain of the ultra-wideband diversity antenna according to the present invention.

Referring to FIG. 6, it can be seen that the amount of change in antenna gain of the WLAN band and the ultra wide band is 0.8 dB and 1.5 dB, respectively. In general, the UWB band can be said to be an excellent antenna when the gain change amount is within 3 dB, but the present invention has excellent gain in terms of gain because the gain change amount is within 3 dB.

Preferred embodiments of the present invention described above are disclosed for purposes of illustration, and those skilled in the art will be able to make various modifications, changes, and additions within the spirit and scope of the present invention. Additions should be considered to be within the scope of the following claims.

1 illustrates a diversity antenna according to a preferred embodiment of the present invention.

FIG. 2 shows S-parameters for an ultra-wideband diversity antenna having Y-shaped radiators and three stubs in accordance with the present invention. FIG.

3 to 4 show simulation results of current flow in the radiator and ground plate according to the present invention.

 5 shows a radiation pattern of an ultra-wideband diversity antenna having a Y-shaped radiator and stub according to the present invention.

6 illustrates the gain of an ultra-wideband diversity antenna according to the present invention.

Claims (13)

A substrate having a predetermined dielectric constant; A ground plate formed of a conductor in a predetermined region of the substrate; A plurality of radiators on the substrate, spaced apart from the ground plate to transmit and receive an RF signal, each of the plurality of radiators spaced apart from each other; A plurality of feed lines for feeding the plurality of radiators; And At least one stub disposed coplanar with the plurality of radiators on the substrate to isolate each radiator, The at least one stub comprises a first to third stub connected to one side of the ground plate. The method of claim 1, And said plurality of radiators, feed lines and stubs are formed by patterning on said substrate. The method of claim 1, The plurality of radiators are Y-shaped and connected to each feed line diversity antenna. The method of claim 3, A diversity antenna for matching impedance through varying lengths of the Y-shaped radiant. delete The method of claim 1, The plurality of radiators includes a first radiator and a second radiator symmetrically disposed on at least one of the first to third stubs on one side of the ground plate. The method of claim 6, The first stub is disposed adjacent to the first radiator, the second stub is disposed adjacent to the second radiator, and the third stub is disposed at the center of the first and second radiators. The method of claim 7, wherein The first and second radiators extend in a direction protruding from the ground plate, the first to third stubs extend in a direction parallel to the radiator. The method of claim 8, The end of the first stub is bent to the first radiation side, the end of the second stub is bent to the second radiation side diversity antenna. The method of claim 7, wherein The diversity antenna is formed longer than the first stub and the second stub. The method of claim 1, The at least one stub is a polygon antenna. The method of claim 1, The plurality of radiators is a diversity antenna for transmitting and receiving frequency signals of a wireless LAN (WLAN) and ultra-wideband (UWB). A substrate having a predetermined dielectric constant; A ground plate formed of a conductor on the substrate; A plurality of radiators spaced apart from one side of the ground plate to transmit and receive an RF signal; A plurality of feed lines for supplying current to the plurality of radiators; And One or more stubs disposed between the plurality of copies to isolate each copy, The at least one stub comprises a first to third stub connected to one side of the ground plate.

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