KR100425571B1 - Multi-band omni antenna in wireless communication system - Google Patents

Abstract

The present invention provides a wireless communication service of several frequency bands at the same time in a shaded area such as an inside of a building, so that an operator providing a wireless communication service of several frequency bands uses only one antenna without installing each antenna for each frequency band. By providing an omni antenna that can provide a wireless communication service. At least one high frequency monopole element for resonating an input high frequency signal; A low frequency monopole element having a portion inserted inside the at least one high frequency monopole element and integrally fixed to the connector with at least one high frequency monopole element so as to resonate the low frequency signal having a lower frequency band than the input high frequency signal; And a reflection plate reflecting the at least one high frequency monopole element and the low frequency monopole element to generate an image current equal to the surface current flowing through the at least one high frequency monopole element and the low frequency monopole element to create a radiation pattern similar to that of the dipole antenna.

Description

Multi-band omni antenna in wireless communication system

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a multiband omni antenna in a wireless communication system, and more particularly to an omni antenna capable of simultaneously relaying several frequency bands in a shaded area such as a building interior.

In general, portable terminals used in wireless communication systems such as digital cellular, personal mobile communication (PCS), and frequency common communication have a different service area according to the user's location, and each service area has various wireless communication relays. Antenna is installed. Accordingly, omni antennas, which can be mounted on ceilings, are used for wireless communication services in shaded areas such as inside buildings.

Such a conventional omni antenna for wireless communication is capable of relaying only a single frequency band, and omni antennas having different frequency bands are used for each frequency band such as cellular, GSM900, PCS / GSM800, and IMT2000.

In addition, the reason why the omni antenna of a single frequency band is mainly used in Korea is that a cellular provider (eg, SK Telecom) provides a service in the 860 MHz band and a PCS provider providing a service in the 1800 MHz band (for example, KT Freetel and Hansol Telecom) have been operating separately.

However, when the IMT2000 business is performed in Korea, the cellular service provider and the PCS service provider must each simultaneously perform the IMT2000 service business with the existing wireless communication service business. In this case, when using a conventional omni antenna of a single frequency band, since the omni antenna suitable for the IMT2000 frequency band should be installed in each service area, the operator has to spend a lot of money on the antenna production, purchase and installation. there was.

Accordingly, the present invention has been made to solve the above problems, by simultaneously providing a wireless communication service of several frequency bands in the same shaded area as the inside of the building, the carrier side providing a wireless communication service of several frequency bands frequency band It is an object of the present invention to provide an omni antenna that can provide a wireless communication service using only one antenna without installing each antenna.

1 is an exploded perspective view of a multi-band omni antenna in a wireless communication system according to an embodiment of the present invention.

FIG. 2 is a coupling diagram of the multiband omni antenna in FIG. 1. FIG.

3 is a cross-sectional view of the multiband omni antenna in FIG.

4 is a cross-sectional view of the monopole element in FIG.

5 is a three-dimensional view of the monopole element in FIG.

6A to 6D are diagrams illustrating the operation of the multiband omni antenna of FIG. 1 in the high frequency band.

7A to 7D are diagrams illustrating the operation in the low frequency band of the multiband omni antenna of FIG.

8A is a characteristic diagram of a horizontal beam pattern in the low frequency band of the dual band omni antenna of FIG.

8B is a characteristic diagram of a vertical beam pattern in the low frequency band of the dual band omni antenna of FIG.

9A is a characteristic diagram of a horizontal beam pattern in the high frequency band of the dual band omni antenna of FIG.

9B is a characteristic diagram of a vertical beam pattern in the high frequency band of the dual band omni antenna of FIG.

10 is a characteristic diagram of an input standing wave ratio of the dual band omni antenna of FIG.

11 is an exploded perspective view of a multiband omni antenna in a wireless communication system according to another embodiment of the present invention.

12 is a cross-sectional view of the monopole element in FIG.

13 is a three-dimensional view of the monopole element in FIG.

Explanation of symbols on the main parts of the drawings

11: connector 12, 13: first and second monopole elements

14: Reflector 15: Radom

16: fixing nut 17: hole

18: dielectric

In order to achieve the above object, the present invention provides an omni antenna for radiating electromagnetic waves input through a connector into a free space in a wireless communication system, wherein at least one high frequency monopole element is used to resonate a high frequency signal input through the connector. ; In order to resonate a low frequency signal having a lower frequency band than the high frequency signal inputted through the connector, a portion is inserted into the at least one high frequency monopole element to be integrally fixed to the at least one high frequency monopole element. Low frequency monopole devices; And a reflecting plate for reflecting the at least one high frequency monopole element and the low frequency monopole element to generate an image current equal to the surface current flowing through the at least one high frequency monopole element and the low frequency monopole element to create a radiation pattern identical to that of a dipole antenna. Include.

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

1 is an exploded perspective view of a multi-band omni antenna in a wireless communication system according to an embodiment of the present invention, showing a dual-band omni antenna.

FIG. 2 is a combined diagram of the dual band omni antenna in FIG. 1.

3 is a cross-sectional view of the dual band omni antenna in FIG. 1.

1 to 3, a dual band omni antenna according to an embodiment of the present invention includes a connector 11 connected to an external cable through which electromagnetic waves are transmitted, and a 1800 to 2000 MHz input through the connector 11. A first monopole element 12 for resonating a high frequency signal in a band, a second monopole element 13 for resonating a low frequency signal in a 800 to 900 MHz band input through the connector 11, and a first and a second 2 reflector 14 for reflecting the monopole elements 12 and 13 to generate the same image current as the surface current flowing through the first and second monopole elements 12 and 13 to produce the same radiation pattern as the dipole antenna; A radome 15 is provided to cover the outside to protect the first and second monopole elements 12 and 13 and the reflecting plate 14.

Here, the connector 11 feeds electromagnetic waves input through the cable connected to the outside to the first and second monopole elements 12 and 13, and the connector 11 is a hole in the center of the reflecting plate 14 It is inserted into the (Hole) (17) and fixed with a fixing nut (16). Thus, the end portion of the center lead of the fixed connector 11 is bolted, and the lower ends of the first and second monopole elements 12 and 13 are fixed by fixing nuts 16 as shown in FIG. 11) and the first and second monopole elements 12 and 13 are connected to each other and positioned on the reflector plate 14. In this case, the length of the dielectric 18 is lengthened so that the first and second monopole elements 12 and 13 are not grounded at the portion where the connector 11 and the first and second monopole elements 12 and 13 are connected. .

The first and second monopole elements 12 and 13 are each made of a plastic cylinder, and the outside of the plastic cylinder is coated with metal to allow current to flow. This is to lighten the weight of the omni antenna to prevent damage to the omni antenna itself if it falls on the floor in the ceiling mounted state or falls on the floor during use.

The diameter of the cylinder constituting the first monopole element 12 is made of a length and thickness enough to pass a high frequency signal in the 1800 to 2000 MHz band, the diameter of the cylinder constituting the second monopole element 13 is 800 to It consists of a length and thickness enough to pass a low frequency signal in the 900 MHz band.

In addition, the first and second monopole elements 12 and 13 are integrally assembled and connected to the connector 11, and a portion of the second monopole element 13 is cylindrical in the first monopole element 12 as shown in FIG. 5. It is inserted inside.

As such, the first and second monopole elements 12 and 13, which are integrally assembled, have a symmetrical structure with respect to the center point of the cylinder, as shown in FIG.

The reflector plate 14 is made of a metal material having good conductivity so as to reflect the surface currents of the first and second monopole elements 12 and 13 to generate the same image current.

The operation characteristics of the dual band omni antenna of the present invention having the above structure in the high frequency band will be described in detail with reference to FIGS. 6A to 6D.

The input electromagnetic wave is fed to the first monopole element 12, which is a high frequency element, through the connector 11 to create an electric field as shown in FIG. 6C between the first monopole element 12 and the reflector 14 to free space. Copied to At this time, since a weak electromagnetic coupling is performed between the second monopole element 13 and the first monopole element 12, which are low frequency elements, the first monopole element 12 affects the second monopole element 13. The diameter sizes of the first and second monopole elements 12 and 13 are designed to receive little.

Thus, when operating in a high frequency band, it is equivalently represented by, as in the dual-band omnidirectional antenna internal current flow Figure 6b of the present invention, the high frequency device of the first monopole element 12 is a high frequency wavelength λ _h "1 It is a 4 "tall monopole antenna.

The process by which the input electromagnetic waves are resonated and radiated by the first monopole element 12 which is such a high frequency element is as follows.

The current flowing through the first monopole element 12 as shown in FIG. 6b is represented as in FIG. 6c as an equivalent signal source for calculating the radiation pattern in part I, and is formed on the surface of the first monopole element 12. The induced surface induced current has the same distribution as in FIG. 6D.

In FIG. 6C, when viewed from the part I of the upper side of the reflector 14, the signal source 1, which is the surface current of the first monopole element 12, which is an actual high frequency element, and the signal source ② of the part II due to the image effect of the reflector 14, are obtained. It is shown as a sum, and the electromagnetic field in part I is analyzed from the dipole current signal sources of the signal source ① and the signal source ②. In other words, the monopole omniantenna combines the surface current induced in the first monopole element 12 with the image current generated from the reflector 14 so that the portion I has the same characteristics as the radiation pattern of the dipole antenna. That is, (3) in FIG. 6C indicates an electric field distribution.

On the other hand, since only the connector 11 having no electromagnetic radiation function is located in the portion II of the reflector 14, there is no radiation signal source of electromagnetic waves.

6A to 6D refer to the cross section of the dual band omni antenna of the present invention, the current flow in the high frequency band inside the dual band omni antenna of the present invention, the first monopole element 12 and the reflector ( 14 shows the electric field distribution formed by 14) and the surface current distribution induced by the first monopole element 12, which is a high frequency element.

Operation characteristics in the low frequency band of the dual band omni antenna of the present invention having the structure as described above will be described in detail with reference to FIGS. 7A to 7D.

The operating principle of the low frequency band is somewhat more complicated than the operating principle in the high frequency band, but the operation characteristics as a basic monopole antenna are similar.

The low frequency signal input through the connector 11 is electromagnetically coupled at the upper end of the first monopole element 12, which is a high frequency element, and electromagnetically coupled to the second monopole element 13, which is a low frequency element, thereby inducing surface current. At this time, the part ④ is a portion where the second monopole element 13, which is a low frequency element, and the first monopole element 12, which is a high frequency element, overlap, and the second monopole element 13, which is an inner conductor, and the first monopole element, which is an outer conductor. (12) acts like a coaxial cable, and the electromagnetic wave applied by electromagnetic coupling in the part ④ is “λ _l / 8” to the lower part connected internally between the first and second monopole elements 12 and 13. reverse meet a short (short) to be merged by moving the drive phase is 180 ° and re-④ to back the sum (3λ _l) / 4 after the time is delayed with the phase difference between the low frequency elements the second monopole element (13 parts Apply surface current with. In addition, there is a component that is directly electromagnetically coupled to the upper portion of the second monopole element 13 in addition to the signal reflected and moved in the coaxial part of the ④ portion, and these two components are combined to provide a surface current to the second monopole element 13. Is formed.

Since the surface current is induced in the second monopole element 13 by the sum of the phase delay component through the coaxial inside and the component directly electromagnetically coupled, it is viewed from outside the first and second monopole elements 12 and 13. When the total surface current has some discontinuous components, the surface current distribution is shown in Fig. 7d. That is, the radiation pattern of the low frequency monopole antenna is calculated as the sum of the surface current of the first monopole element 12 and the surface current of the second monopole element 13. The current flow inside the omni antenna of the present invention is as in FIG. 7B.

However, the surface current distribution shown in FIG. 7D is no abnormal for operation as a monopole antenna, but rather has an advantage of increasing the frequency bandwidth. At this time, the radiation pattern analysis at the low frequency is the same as the operation principle in the high frequency band described above.

The process by which the input electromagnetic waves are resonated and radiated by the second monopole element 13 which is such a low frequency element is as follows.

Electromagnetic waves input through the connector 11 induce surface currents in the coaxial monolithic first and second monopole elements 12 and 13 and in combination with the image components in part II of FIG. 7C produced by the reflector plate 14 of FIG. Part I produces the same radiation pattern as a dipole antenna. In this case, the sum of the total surface currents of the first and second monopole elements 12 and 13 is equivalent to a quarter height of the low frequency band wavelength λ _l to operate as a monopole antenna, and the first and second monopole elements ( It is operated by electromagnetic wave coupling between 12 and 13), thus making a wider bandwidth.

In Fig. 7C,? Is the surface current for the low frequency band signal on the surfaces of the first and second monopole elements 12 and 13, and in Fig. 7C,? Is the electric field distribution in part I generated between the surface current and the image current. .

7A to 7D refer to a cross section of the dual band omni antenna of the present invention, the current flow in the low frequency band inside the dual band omni antenna of the present invention, and the first and second monopole elements 12 and 13, respectively. The electric field distribution formed by the reflector 14 and the surface current distribution induced by the first and second monopole elements 12 and 13 are shown.

FIG. 8A illustrates a characteristic diagram of a radiation pattern in a low frequency band of the dual band omni antenna of FIG. 1 and illustrates characteristics of a horizontal beam pattern in a 900 MHz band.

FIG. 8B illustrates a characteristic diagram of a radiation pattern in a low frequency band of the dual band omni antenna of FIG. 1 and illustrates characteristics of a vertical beam pattern in a 900 MHz band.

FIG. 9A illustrates a characteristic diagram of a radiation pattern in a high frequency band of the dual band omni antenna of FIG. 1 and illustrates characteristics of a horizontal beam pattern in a 1800 MHz band.

FIG. 9B illustrates a characteristic diagram of a radiation pattern in a high frequency band of the dual band omni antenna of FIG. 1 and illustrates characteristics of a vertical beam pattern in a 1800 MHz band.

FIG. 10 illustrates characteristics of an input standing wave ratio of the dual band omni antenna of FIG. 1.

FIG. 11 is an exploded perspective view of a multiband omni antenna in a wireless communication system according to another embodiment of the present invention, in which the frequency band of the dual band omni antenna of FIG. 1 is expanded.

Referring to FIG. 11, in the multi-band omni antenna according to another embodiment of the present invention, as in FIG. 1, the connector 11, the first monopole element 12, the second monopole element 13, and the reflector plate 14 are described. And a radome 15, and a third monopole element 19 for resonating high frequency signals in a band higher than the 1800 to 2000 MHz band.

The connector 11 is fixed by the fixing nut 16, and the assembly of the connector 11 and the first to third monopole elements 12, 13, and 19 are connected to the fixing plate 16 and positioned on the reflector plate 14. Done.

The first to third monopole elements 12, 13, and 19 are formed in a cylindrical shape made of plastic and composed of metal conductor components.

The diameter of the cylinder constituting the third monopole element 19 is such that a high frequency signal in a band higher than the 1800 to 2000 MHz band is resonated.

The first to third monopole elements 12, 13, and 19 are fabricated in an integrated coaxial symmetric structure.

As such, the first to third monopole elements 12, 13, and 19 that are integrally assembled have a symmetrical structure on the ground plate with respect to the center point of the cylinder, as shown in FIGS.

Therefore, the multiband omni antenna of the present invention can radiate signals of a wider frequency band by varying the diameter size of the symmetric cylindrical monopole elements as described above.

And, the operation characteristics of the multi-band omni antenna of the present invention as shown in Figure 11 is the same as the operation principle of the dual band omni antenna of FIG.

Although the technical spirit of the present invention has been described in detail according to the above-described preferred embodiment, it should be noted that the above-described embodiment is for the purpose of description and not of limitation. In addition, those skilled in the art will understand that various embodiments are possible within the scope of the technical idea of the present invention.

As described above, according to the present invention, by simultaneously relaying several frequency bands using one multi-band omni antenna in the same region, the operator can significantly reduce the cost required for antenna production, purchase, and installation.

Claims (6)

In the omni antenna for radiating the electromagnetic wave input through the connector to a free space in a wireless communication system, A high frequency monopole element for resonating a high frequency signal input through the connector; A low frequency monopole element having a portion inserted into the high frequency monopole element and fixed integrally with the high frequency monopole element to the connector so as to resonate a low frequency signal having a frequency band lower than that of the high frequency signal input through the connector; And Reflecting the high frequency monopole element and the low frequency monopole element to generate the same image current as the surface current flowing through the high frequency monopole element and the low frequency monopole element to produce the same radiation pattern as the dipole antenna, the high frequency monopole element and the low frequency monopole element A reflector for copying the low frequency signal and the high frequency signal resonated from each other into free space Multiband omni antenna comprising a. The method of claim 1, The high frequency monopole element and the low frequency monopole element are each formed of an integral cylindrical structure made of a plastic material, the multi-band omni antenna characterized in that the outer surface of the plastic cylinder is coated with metal so that a current can flow. The method of claim 2, The diameter of the cylinder constituting the high frequency monopole element is larger than the diameter of the cylinder constituting the low frequency monopole element. The method of claim 2, And a cylinder constituting the high frequency monopole element and a cylinder constituting the low frequency monopole element are symmetrical with respect to a center point, respectively. The method according to any one of claims 1 to 4, The high frequency monopole device substantially resonates a high frequency signal in the 1800 to 2000 MHz band, And said low frequency monopole device substantially resonates a low frequency signal in the 800 to 900 MHz band. delete