KR20030094467A - Circularly polarization antenna having diversity function - Google Patents

Abstract

PURPOSE: A circularly-polarized wave antenna having a diversity function is provided to transmit or receive a left and a right circularly-polarized wave signal of different transmission paths by using a first and a second circularly-polarized wave elements having a phase difference of 45 degrees therebetween. CONSTITUTION: A circularly-polarized wave antenna having a diversity function includes a reflective plate(500), a first circularly-polarized wave element(510), and a second circularly-polarized wave element(520). The first circularly-polarized wave element(510) is formed with a first dipole and a second dipole. The first dipole has an angle of 0 degree to a vertical plane of the reflective plate(500). The second dipole has an angle of 90 degrees to the vertical plane of the reflective plate(500). The second circularly-polarized wave element(520) is formed with a third and a fourth dipoles. The third dipole has the angle of 0 degree to the vertical plane of the reflective plate(500). The fourth dipole has the angle of 90 degrees to the vertical plane of the reflective plate(500). A phase difference between the first and the second dipoles and the third and the fourth dipoles is 45 degrees.

Description

Circularly polarized antenna with diversity function {CIRCULARLY POLARIZATION ANTENNA HAVING DIVERSITY FUNCTION}

The present invention relates to a circularly polarized antenna of a mobile communication system, and more particularly, to a circularly polarized antenna having a diversity function for efficiently performing signal transmission in an area with high multipath fading effects.

In today's society, mobile telephone terminals have become so popular that they are a necessity of life, so that one out of two people in Korea and more than one in every household have spread.

As such, the reason why the number of domestic mobile phone subscribers is increasing exponentially is because it is easy to carry and calls can be made while on the move. However, in order to communicate using this convenient mobile phone, a mobile communication system connects each other so that subscribers who are scattered about each other can talk to each other like a wired phone that connects to individual users by wire or optical cable. This is necessary.

One of the important factors in wireless network design is the base station, and basically, in order to expand the communication area, many base stations must be established.

Unlike wired communication, since mobile signals propagate through the air, signals emitted through the terminal antenna of mobile subscribers propagate through the air, and are signaled by buildings, houses, and other geographic obstacles such as buildings and mountains. Attenuation occurs.

In addition, the signal reflected and diffracted by the obstacle or the like does not propagate through one path, but propagates through several paths.

Therefore, the base station must receive all signals received through multiple paths for the call between users using the mobile phone terminal.

That is, the base station receives signals having different attenuation and paths, but the phenomenon that the amplitude of the received signal increases and decreases. This phenomenon is called multi-path fading.

In order to alleviate the multipath fading phenomenon, a diversity scheme is used at the base station.

The basic concept of the diversity scheme is to use two receive antennas at the receiving end.

That is, when two receiving antennas respectively receive two signals having different paths, even if a deep fading phenomenon occurs in a signal received by one receiving antenna, the signal received by the other receiving antenna generates a small fading phenomenon. Selecting and playing back a few fading signals will provide a good quality call.

A mobile communication system using a diversity technique according to the prior art will be described with reference to the accompanying drawings.

1 is a view showing a mobile communication system using a vertical polarization antenna according to the prior art.

As shown in FIG. 1, the mobile communication system according to the related art uses a signal from a mobile communication terminal (not shown) through a first vertical polarization antenna 100 and a second vertical polarization antenna 110 configured to be spaced apart by a predetermined distance. Receive

In this case, the first and second vertical polarization antennas 100 and 110 are spaced apart by 10λ.

The signals received by the first and second vertically polarized antennas 100 and 110 are input to the base station signal processor 120.

Here, the spatial divers that the first vertical polarization antenna 100 and the second vertical polarization antenna 110 spaced apart from each other may independently receive the same signal transmitted from the mobile communication terminal at a difference of about 10λ of the carrier frequency wavelength. Use city technology.

That is, the base station signal processing unit 120 receives the signal transmitted from the mobile communication terminal by the first vertical polarization antenna 100 and the second vertical polarization antenna 110 at two points sufficiently separated from each other. The effect of fading can be reduced by receiving and signal processing signals whose fading states are independent of each other.

At this time, the spatial diversity technique obtains a diversity gain of about 3 to 5 dB in the reverse direction.

2 is a diagram illustrating a mobile communication system using a dual polarized antenna according to the prior art.

Referring to FIG. 2, a base station according to the related art includes a dual polarized antenna 200 for receiving signals having different polarizations.

Here, the dual polarized antennas 200 are antennas having a polarization characteristic of 45 ° from side to side in the vertical direction.

Polarization of a signal transmitted from a mobile communication terminal (not shown) is reflected or diffracted by a building, an obstacle, or the like, and the polarization characteristic thereof is changed, and signals having multiple paths have different polarizations.

In this case, when the dual polarized antenna 200 transmits two signals having independent fading characteristics, that is, a vertical polarized signal from the mobile communication terminal, the dual polarized antenna 200 has a probability of receiving a polarized signal 45 ° left and right from the vertical direction.

Here, the polarized signals 45 ° tilted to the left and right received by the dual polarized antenna 200 are signals having the lowest correlation with each other.

As such, the base station signal processing unit 210 may receive a signal having low multipath fading by combining the two signals after receiving the 45 ° tilted polarization signal having the lowest correlation with each other using the dual polarization antenna 200. .

When a mobile communication service is performed in an area having a complex feature such as a city center, the signal transmitted from the base station to the mobile terminal is significantly reduced in strength due to fading.

One of the factors that reduces the signal strength due to fading is that the polarization plane of the radio wave is changed due to reflection by a building or the like, which causes the signal strength to decrease.

That is, the vertically polarized signal transmitted from the base station changes the polarized plane into a circular or elliptical polarization by primary reflection by a building, etc., and thus generates a polarization loss of at least 3 dB.

In addition, when the multipath fading is severe, the loss due to the polarization variation is at least 8 dB to 16 dB or more.

As described above, when the vertical polarization antenna or the dual polarization antenna is used, the mobile terminal deteriorates the reception level due to the loss caused by the polarization plane variation, and thus requires more power to be sent to the base station, which consumes more battery. .

Therefore, in the mobile communication system according to the prior art, as the mobile communication terminal needs to consume more battery, the maximum callable time of the mobile communication subscriber is reduced, which causes a problem of increasing the dissatisfaction of the mobile communication subscriber.

In addition, the conventional mobile communication system also has a problem that the base station has to increase the transmission power in order to increase the reception level of the mobile communication terminal.

Accordingly, an object of the present invention is to provide a circularly polarized antenna having a diversity function for transmitting and receiving circularly polarized signals having different reception paths.

1 is a view showing a mobile communication system using a vertical polarization antenna according to the prior art.

2 is a diagram illustrating a mobile communication system using a dual polarized antenna according to the prior art.

3 is a view showing the direction of the electric field and the propagation propagation direction according to the polarity of the radio waves.

4 shows two electric field polarities of circular polarization polarity.

5 is a schematic view of a circularly polarized antenna having a diversity function according to the first embodiment of the present invention.

6 is a schematic structural diagram of a circularly polarized antenna having a diversity function according to a second embodiment of the present invention;

<Description of the code for the main part>

500: reflector plate 510: first circularly polarized element

520: second polarization element 530: circular polarization antenna

540: base station signal processing unit

The present invention for achieving the above object is a first circular polarization element constituted by a reflecting plate, a first dipole making 0 ° on the vertical plane of the reflecting plate, and a second dipole making 90 ° on the vertical plane of the reflecting plate, on the vertical plane of the reflecting plate. A third dipole that is 0 ° and a fourth dipole that is 90 ° on the vertical plane of the reflector, and the third and fourth dipoles are configured to have a 45 ° phase difference with respect to the first and second dipoles. It is a feature to provide a circularly polarized antenna having a diversity function, characterized in that it comprises a circularly polarized element.

Here, the plurality of first circularly polarized elements are arranged vertically in a row on the reflection plate, and the plurality of second circularly polarized elements are arranged in the vertical line so as to correspond to the first circularly polarized elements on the reflection plate.

According to another aspect of the present invention, in a circular polarization antenna for transmitting or receiving a signal to a mobile communication terminal, a first dipole of 0 ° on a vertical plane of the first reflector and a second dipole of 90 ° on a vertical plane of the first reflector A first circularly polarized antenna having a first circularly polarized element constituted by a second third pole formed by 0 ° on the vertical plane of the second reflector and a fourth dipole made by 90 ° on the vertical plane of the second reflector. The present invention provides an antenna system having a diversity function, comprising a circularly polarized element, and comprising a second circularly polarized antenna spaced apart from the first circularly polarized antenna by a predetermined distance of at least 8λ.

Here, the plurality of first circularly polarized elements are arranged in a vertical line on the first reflecting plate, and the plurality of second circularly polarized elements are arranged in a vertical line on the second reflecting plate.

Hereinafter, a preferred embodiment of a circular polarization antenna having a diversity function according to the present invention will be described in detail with reference to the accompanying drawings.

First, a mobile communication terminal using a linear antenna has a higher probability of receiving a circularly polarized signal than a linearly polarized signal.

The reason for this will be described with reference to FIGS. 3 and 4 as follows.

3 is a view showing the direction of the electric field and the direction of propagation according to the polarity of the radio wave, Figure 4 is a view showing the two electric field polarity of the circularly polarized polarity.

As shown in FIG. 3, the linearly polarized wave has an electric field formed perpendicular to the propagation direction of the radio wave, and the circularly polarized wave has a left circular circular polarization in which the electric field rotates in the left or right direction when viewed in the propagation direction of the radio wave over time. And circular polarization is first formed.

Radio waves propagate into the atmosphere, and then travel through various paths and encounter polarity, such as buildings or trees, to reverse polarity.

At this time, in order to obtain the highest intensity of the radio wave, it is preferable that the polarity of the antenna receiving the radio wave matches the polarity of the radio wave.

In general, a mobile terminal uses a linear antenna. If the polarity of the radio wave and the polarity of the antenna of the mobile terminal coincide, all the radio waves can be received. However, the polarity of the radio wave impacted by various paths and obstacles is determined by the mobile terminal. Does not always match the polarity of

In addition, as shown in Fig. 4, the electric field of the circular polarization is composed of two components, and these two components are always vertical, and the polarity is possible in all directions about the circle.

In the visible distance, the linear polarization can receive the strength of all radio waves because the antenna polarities of the mobile communication terminals match each other. Is cut in half.

However, since the circular polarization is composed of two components, even if the polarity is changed by reflection and scattering due to obstacles such as buildings or trees, the antenna of the mobile communication terminal has a high probability of receiving the same polarity as compared to the linear polarization. Better than linear polarization.

Therefore, mobile communication service using circular polarization is more efficient in urban areas with many obstacles.

It is more efficient to use a circularly polarized antenna in a mobile communication system in urban areas where multipath fading is likely to occur due to the above reasons.

5 is a diagram schematically illustrating a circularly polarized antenna having a diversity function according to a first embodiment of the present invention.

Referring to FIG. 5, the mobile communication system according to the present invention includes a circular polarization antenna 530 having a reflector plate 500, a first circular polarization element 510, and a second circular polarization element 520, and a base station signal processor 540. ).

The first circularly polarized element 510 is constituted by a dipole forming 90 ° and a dipole forming 0 ° on a vertical plane of the reflecting plate 500. In addition, the second circularly polarized element 520 has a phase difference of 45 ° with the first circularly polarized element 510 and is constituted by a dipole which is 90 ° with a dipole which is 0 ° on a vertical plane of the reflector 500.

Here, the first circular polarization element 510 and the second circular polarization element 520 are configured in pairs.

That is, when the first circular polarization element 510 first transmits and receives a circular polarization signal, the second circular polarization element 520 transmits and receives a left circular polarization signal, and the first circular polarization element 510 transmits a left circular polarization signal. When transmitting and receiving, the second circularly polarized element 520 first transmits and receives the circularly polarized signal.

The circularly polarized antenna 530 according to the present invention has a plurality of first circularly polarized elements arranged vertically in a row, and a plurality of second circles arranged in a vertical line at a position paired with the first circularly polarized element 510. It is configured to have a polarization element.

The first circular polarization element 510 and the second circular polarization element 520 convert a left line circular polarization signal and a first circular polarization signal received from a mobile communication terminal (not shown) into signals having different reception paths. It is configured to output to the signal processor 540.

In addition, the circular polarization antenna 530 according to the present invention is a mobile communication of the left circular polarization signal and the preferential circular polarization signal having different reception paths by the first circular polarization element 510 and the second circular polarization element 520. Configured to transmit to the terminal.

The operation of the circularly polarized antenna having the diversity function according to the first embodiment of the present invention configured as described above is as follows.

First, the circularly polarized antenna 530 receives a signal from a mobile communication terminal.

In this case, the signal transmitted from the mobile communication terminal and received by the circular polarization antenna 530 includes a first circular polarization signal and a left circular polarization signal converted by reflection by an obstacle such as a city building.

The first circular polarization element 510 of the circular polarization antenna 530 first receives a circular polarization signal (or left line circular polarization signal), and the second circular polarization element 520 receives a left line circular polarization signal (or first circular polarization signal). ).

Subsequently, the first circular polarization element 510 outputs the received first circular polarization signal (or left circular polarization signal) to the base station signal processor 540, and the second circular polarization element 520 receives the received left circular polarization signal. (Or first, the circularly polarized signal) is output to the base station signal processing unit 540.

Here, since the first circular polarization element 510 and the second circular polarization element 520 are configured to have a phase difference of 45 °, the first circular polarization signal and the left circular polarization signal input to the base station signal processor 540 are mutually different. It is a signal independent of each other in time through different receiving paths.

The base station signal processor 540 obtains a diversity gain by combining the first circular polarization signal and the left circular polarization signal that are independent of each other in time.

On the other hand, the circularly polarized antenna 530 receives a signal for transmission from the base station signal processor 540 to the mobile communication terminal.

The circularly polarized antenna 530 receives a signal input from the base station signal processor 540 by the first circularly polarized element 510 and the second circularly polarized element 520, and has a left line circularly polarized signal having a different reception path and a preferred circle. The signal is converted into a polarized signal and transmitted to the mobile communication terminal.

Here, the mobile communication terminal can obtain diversity gain by separately demodulating the left line circular polarization signal and the first circular polarization signal that are independent of each other in time as they have different transmission paths through an internal rake receiver (not shown). have.

As described above, the circular polarization antenna having the diversity function according to the first embodiment of the present invention has been described taking an example of a configuration connected to a signal processing unit of a base station, but a repeater for relaying a radio signal between the base station and the mobile communication terminal. It is obvious that it can be configured.

6 is a schematic structural diagram of a circularly polarized antenna having a diversity function according to a second embodiment of the present invention.

Referring to FIG. 6, the circular polarization antenna system according to the second embodiment of the present invention includes a first circular polarization antenna 600 and a second circular polarization antenna 610 that receive a left circular polarization signal or a preferential circular polarization signal. It is composed of a predetermined distance (S) spaced apart.

Here, the predetermined distance that the first circularly polarized antenna 600 and the second circularly polarized antenna 610 is spaced apart is at least 8λ.

In addition, the first circularly polarized antenna 600 includes a reflecting plate 602, a first circularly polarizing element 604 constituted by a dipole forming 0 ° and a dipole forming 90 ° on a vertical plane of the reflecting plate 602. In this case, the first circularly polarized antenna 600 includes a plurality of first circularly polarized elements 604 arranged vertically on the reflection plate 602.

The second circularly polarized antenna 610 includes a reflecting plate 612, a second circularly polarizing element 614 constituted by a dipole forming 0 ° and a dipole forming 90 ° on a vertical plane of the reflecting plate 612. The second circularly polarized antenna 610 includes a plurality of second circularly polarized elements arranged vertically on the reflector plate 612.

The first circularly polarized antenna 600 and the second circularly polarized antenna 610 convert a left circularly polarized signal and a first circularly polarized signal received from a mobile communication terminal (not shown) into signals having different receiving paths, thereby converting the base station into a base station. It is configured to output to the signal processor 620.

In addition, the first circularly polarized antenna 600 and the second circularly polarized antenna 610 convert a signal input from the base station signal processor 620 into a left line circularly polarized signal having a different reception path and a first circularly polarized signal, and then move. And transmit to the communication terminal.

The operation of the circularly polarized antenna having the diversity function according to the second embodiment of the present invention configured as described above will be described.

First, the first circularly polarized antenna 600 and the second circularly polarized antenna 610 receive a signal from a mobile communication terminal (not shown).

At this time, the signal received from the mobile communication terminal is a left circularly polarized signal and a first circularly polarized signal whose polarization plane is deformed by being reflected by obstacles in the city center.

The first left circular polarization signal (or first preferred circular polarization signal) received by the first circular polarization antenna 600 and the second left circular polarization signal (or second preferred circle) received by the second circular polarization antenna 610. Polarized signals) have different transmission paths.

That is, since the first circular polarization antenna 600 and the second circular polarization antenna 610 are configured to be spaced apart from each other by a predetermined distance, the received first left circular polarization signal (or first preferred circular polarization signal) and the second left circular polarization are polarized. The signal (or second preferred circularly polarized signal) has different transmission paths.

The base station signal processor 620 may include a first left circular polarization signal (or a first preferred circular polarization signal) and a first transmission path having different transmission paths received by the first circular polarization antenna 600 and the second circular polarization antenna 610. Diversity gain is obtained by combining the two left-hand circularly polarized signal (or second preferred circularly polarized signal).

Meanwhile, the first circularly polarized antenna 600 and the second circularly polarized antenna 610 transmit a signal input from the base station signal processor 620 to a first left line circularly polarized signal (or a first preferred circularly polarized signal) and a second left line. The signal is converted into a circularly polarized signal (or second preferred circularly polarized signal) and transmitted to the mobile communication terminal.

Here, the first left circular polarization signal (or first preferred circular polarization signal) and the second left circular polarization signal (or second preferred circular polarization signal) transmitted to the mobile communication terminal have different transmission paths.

That is, since the first circular polarization antenna 600 and the second circular polarization antenna 610 are configured to be spaced apart from each other by a predetermined distance, the first left circular polarization signal (or first preferred circular polarization signal) and the second left circular polarization signal ( Or second preferred circularly polarized signal) have different transmission paths.

The mobile communication terminal distinguishes and demodulates a first left circular polarization signal (or a first preferred circular polarization signal) and a second left circular polarization signal (or a second preferred circular polarization signal) having different transmission paths. Get

As described above, the circular polarization antenna having the diversity function according to the second embodiment of the present invention has been described taking an example of a configuration connected to a signal processing unit of a base station, but a repeater for relaying a radio signal between the base station and the mobile communication terminal. It is obvious that it can be configured.

A circular polarization antenna having a diversity function according to the present invention transmits and receives a first circular polarization signal and a left circular polarization signal having different transmission paths by a first circular polarization element and a second circular polarization element having a phase difference of 45 ° from each other. do.

In addition, the circularly polarized antenna having a diversity function according to the present invention transmits and receives a first circular polarization signal and a left circular polarization signal having different transmission paths by a first circular polarization antenna and a second circular polarization antenna having a predetermined distance. do.

Therefore, the present invention has the effect of reducing the battery consumption of the mobile communication terminal by minimizing the effects of multipath fading that may occur on the reception paths of the base station and the repeater for the wireless communication service.

In addition, the present invention can reduce the cost of the power amplifier to increase the transmission strength of the signal by minimizing the multipath fading effect that can occur on the transmission path of the base station and the repeater can also reduce the cost.

Although the above has been described with reference to the preferred embodiments of the present invention, those skilled in the art to which the present invention pertains without departing from the spirit and scope of the present invention as set forth in the claims below It will be appreciated that modifications and variations can be made.

Claims (5)

Reflector; A first circularly polarized element constituted by a first dipole forming 0 ° on the vertical plane of the reflecting plate and a second dipole forming 90 ° on the vertical plane of the reflecting plate; And a fourth dipole forming a 0 degree on the vertical plane of the reflector and a fourth dipole making a 90 degree on the vertical plane of the reflecting plate, wherein the third dipole and the fourth dipole are connected to the first dipole and the second dipole. Second circular polarization element configured to have a 45 ° phase difference with respect to Circularly polarized antenna having a diversity function comprising a. The method of claim 1, The first circularly polarized element is arranged in a plurality of vertically arranged on the reflecting plate, And a plurality of the second circularly polarized elements are arranged in a row in the vertical direction so as to correspond to the first circularly polarized elements on the reflecting plate. In the circular polarization antenna for transmitting or receiving a signal to a mobile communication terminal, A first circularly polarized antenna having a first circularly polarized element constituted by a first dipole forming 0 ° on a vertical plane of the first reflector and a second dipole 90 ° on a vertical plane of the first reflector; A second circularly polarized element constituted by a third dipole forming 0 ° on the vertical plane of the second reflector and a fourth dipole 90 ° on the vertical plane of the second reflector, and spaced apart from the first circularly polarized antenna by a predetermined distance Circularly polarized antenna installed and installed Antenna system having a diversity function characterized in that comprises a. The method of claim 3, The predetermined distance is at least 8λ circular polarization antenna system having a diversity function. The method of claim 3, The first circularly polarizing element is arranged in a plurality of vertically arranged on the first reflecting plate, The second circularly polarized element is a circular polarization antenna system having a diversity function, characterized in that a plurality of vertically arranged on the second reflecting plate.