KR101974689B1 - Dipole espar antenna - Google Patents

Abstract

The present invention relates to an active device comprising an active element composed of a cylindrical dipole structure divided into a positive region and a negative region spaced apart from the positive region and an active element disposed on at least one side of the active element, There is provided a dipole ESPAR antenna including a positive pattern and a parasitic element spaced apart from the positive pattern and formed of a planar dipole structure divided into a negative pattern electrically connected to the negative region .

Description

A dipole ESPAR antenna {DIPOLE ESPAR ANTENNA}

The present invention relates to a dipole ESPAR antenna, and more particularly, to a dipole ESPAR antenna with simplified antenna structure and control circuitry and improved VSWR characteristics of the antenna.

Recently, a lot of smart antennas are being studied for communication services that solve rapidly increasing data traffic according to the flow of high speed communication.

In general, a smart antenna array antenna and a digital beamforming antenna require a frequency down converter, a low-noise amplifier, an A / D converter, and a D / A converter for each array element, It is also expensive.

An ESPAR (Electronically Steerable Parasitic Array Radiator) is an antenna with a single RF chain and several parasitic elements.

Using an ESPAR antenna, a single RF chain, can reduce complexity and power consumption over antennas or array antennas that use multiple RF chains.

The parasitic elements included in the ESPAR antenna are connected to a reatance load, and the pattern of the ESPAR antenna is controlled by the reactance value connected to each of the parasitic elements.

In recent years, studies are underway to change the reactance load reactance connected to each of the parasitic elements included in the ESPAR antenna for beam steering, and to realize the antenna structure and the control circuit accordingly.

It is an object of the present invention to provide a dipole ESPAR antenna with simplified antenna structure and control circuit and improved VSWR characteristics of the antenna.

The dipole ESPAR antenna according to the present invention includes an active element made of a cylindrical dipole structure divided into a positive region and a negative region spaced apart from the positive region, And may include a positive pattern and a parasitic element spaced apart from the positive pattern and formed of a planar dipole structure divided into a negative pattern electrically connected to the negative region have.

The dipole ESPAR antenna may further include a variable element that is soldered to the positive pattern and the negative pattern so that the reactance of the parasitic element is variable.

Here, the variable element may be a varactor diode.

Here, the parasitic element may be formed of copper on the substrate having a predetermined relative dielectric constant, and the positive pattern and the negative pattern may be formed.

The substrate may be an FR-4 material having the relative dielectric constant of 4.1 to 4.4.

Here, the thicknesses of the positive pattern and the negative pattern may be 0.031 mm to 0.37 mm, and the widths of the positive pattern and the negative pattern may be 7 mm to 10 mm.

The dipole ESPAR antenna may further include a coaxial cable for applying a positive voltage and a negative voltage to the active element, The negative voltage is applied, and the positive region can be contacted with the coaxial cable inserted in the negative region to apply the positive voltage.

In addition, the active element may be spaced apart from the parasitic element by 7.3 mm to 7.8 mm.

The dipole ESPAR antenna may further include a rear substrate on which a connection pattern connecting the negative region and the negative pattern is formed.

Here, the connection pattern may be a quarter-wave meander strip line.

The dipole ESPAR antenna according to the present invention is configured such that the negative region of the active element and the negative pattern of the parasitic element are connected to each other and serve as a common ground so that the voltage applied to the positive pattern of the parasitic element and the variable element soldered to the negative pattern The structure complexity of the antenna can be reduced and a connection pattern connecting the negative region of the active element and the negative pattern of the parasitic element is formed into a strip line.

1 is a perspective view of a dipole ESPAR antenna according to the present invention.
2 is a cross-sectional view of the dipole ESPAR antenna shown in Fig.
3 is a plan view showing a top surface of the dipole ESPAR antenna shown in Fig.
4 is a plan view showing a bottom surface of the dipole ESPAR antenna shown in Fig.
FIG. 5 is a diagram illustrating a characteristic of a VSWR of a dipole ESPAR antenna according to the present invention.
FIG. 6 is a diagram illustrating a radiation pattern for a dipole ESPAR antenna in FIG.
FIG. 7 is a diagram illustrating a radiation pattern when a reactance of a parasitic element is varied in a dipole ESPAR antenna according to the present invention.

While the invention is susceptible to various modifications and alternative forms, specific embodiments thereof are shown by way of example in the drawings and will herein be described in detail. It should be understood, however, that the invention is not intended to be limited to the particular embodiments, but includes all modifications, equivalents, and alternatives falling within the spirit and scope of the invention.

The terms first, second, etc. may be used to describe various components, but the components should not be limited by the terms. The terms are used only for the purpose of distinguishing one component from another. For example, without departing from the scope of the present invention, the first component may be referred to as a second component, and similarly, the second component may also be referred to as a first component. And / or < / RTI > includes any combination of a plurality of related listed items or any of a plurality of related listed items.

It is to be understood that when an element is referred to as being "connected" or "connected" to another element, it may be directly connected or connected to the other element, . On the other hand, when an element is referred to as being "directly connected" or "directly connected" to another element, it should be understood that there are no other elements in between.

The terminology used in this application is used only to describe a specific embodiment and is not intended to limit the invention. The singular expressions include plural expressions unless the context clearly dictates otherwise. In the present application, the terms "comprises" or "having" and the like are used to specify that there is a feature, a number, a step, an operation, an element, a component or a combination thereof described in the specification, But do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components, or combinations 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 to which this invention belongs. Terms such as those defined in commonly used dictionaries should be interpreted as having a meaning consistent with the meaning in the context of the relevant art and are to be interpreted in an ideal or overly formal sense unless explicitly defined in the present 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 the understanding of the present invention, the same reference numerals are used for the same constituent elements in the drawings and redundant explanations for the same constituent elements are omitted.

FIG. 1 is a perspective view of a dipole ESPAR antenna according to the present invention, FIG. 2 is a sectional view of a dipole ESPAR antenna shown in FIG. 1, FIG. 3 is a top view of an upper surface of a dipole ESPAR antenna shown in FIG. 1 is a plan view showing a bottom surface of the dipole ESPAR antenna shown.

Referring to FIGS. 1 and 4, the dipole ESPAR antenna 100 may include an active element 110 and a parasitic element 120.

First, the dipole ESPAR antenna 100 is described as being formed of four side portions, an upper surface portion, and a lower surface portion to form a case into which the active element 110 is inserted. However, the form, structure, etc. of the case are not limited .

The active element 110 may be a cylindrical dipole antenna consisting of a positive region 112 and a negative region 114 spaced apart from the positive region 112.

At this time, the positive region 112 of the active element 110 may be electrically connected to the internal conductor 116a of the connector 116 inserted in the negative region 114.

Here, the connector 116 may include an inner conductor 116a, an insulator 116b, and an outer conductor 116c, and may be coupled to a coaxial cable that is connected to the RF chain to form a positive region 112 and a negative region 114 The power can be applied.

The negative region 114 of the active element 110 may be electrically connected to the external conductor 116c of the connector 116. [

That is, the negative region 114 may be formed with a hole (not shown) into which the connector 116 is inserted.

Here, the radius R of the positive region 112 and the negative region 114 may be 4 mm to 6 mm, and they may have the same radius R, but are not limited thereto.

Although the connector 116 is shown as being inserted and coupled into the negative region 114 in the embodiment, the coaxial cable may be inserted into and coupled to the negative region 114, but is not limited thereto.

The parasitic element 120 may be formed with four side portions forming the case as described above. In this embodiment, the parasitic elements 120 are described as being formed on each of the four side portions.

That is, the parasitic element 120 may include a side substrate 122, a positive pattern 124, and a negative pattern 126.

The parasitic element 120 may have a planar dipole structure divided into a positive pattern 124 and a negative pattern 126 and may have a dipole structure different from that of the active element 110.

Here, the side substrate 122 is an FR-4 material having a predetermined relative dielectric constant, and the relative dielectric constant may be 4.1 to 4.4, but is not limited thereto.

The positive pattern 124 and the negative pattern 126 can be formed by disposing copper on the side substrate 122.

That is, the thickness D of the positive pattern 124 and the negative pattern 126 may be 0.031 mm to 0.37 mm, and the width W of the positive pattern 124 and the negative pattern 126 may be 7 mm to 10 mm But is not limited thereto.

Here, the active element 110 may be spaced apart from the parasitic element 120 by a predetermined distance B with respect to the center of the active element 110.

That is, the predetermined distance B may be 7.3 mm to 7.8 mm, but is not limited thereto.

The dipole ESPAR antenna 100 of the present invention includes a variable element 140 soldered to the positive pattern 124 and the negative pattern 126 to vary the reactance of the parasitic element 120 .

In the embodiment, the variable element 140 is described as soldered to the positive pattern 124 and the negative pattern 126, but may be electrically connected by other methods, but is not limited thereto.

The variable element 140 can vary the reactance of the parasitic element 120 by varying the resistance value by the input voltage.

In other words, the parasitic element 140 can control the advancing direction of the beam to be diverged by varying the liquid crystal by the variable element 140.

The upper surface of the dipole ESPAR antenna 100 shown in FIG. 3, that is, the upper surface substrate 132, has an opening s1 to open the upper portion of the positive region 112 of the active element 110, But may be of the same FR-4 material as the side substrate 122, but is not limited thereto.

The back surface of the dipole ESPAR antenna 100 shown in Fig. 4, that is, the rear substrate 134 is patterned on the substrate 134a and the substrate 134a, which are the same FR-4 material as the side substrate 122, And a connection pattern 134b for electrically connecting the negative region 114 of the parasitic element 110 and the negative pattern 126 of the parasitic element 120. [

The connection pattern 134b is a quarter-wave meander strip line and electrically connects the negative region 114 of the active element 110 and the negative pattern 126 of the parasitic element 120, .

As described above, the variable element 140 is electrically connected to the positive pattern 124 and the negative pattern 126, and the voltage applied to the variable element 140, that is, the voltage supplied from the above- The voltage supplied to each of the variable element 140 and the negative pattern 126 is applied through the connection pattern 134b so that the number of the voltage bias lines is set to be Can be reduced.

FIG. 5 is a graph illustrating the VSWR characteristics of a dipole ESPAR antenna according to the present invention. FIG. 6 is a diagram illustrating a radiation pattern for a dipole ESPAR antenna in FIG. 5, and FIG. Fig. 5 shows a radiation pattern when the reactance of the parasitic element is varied.

5 and 6 show a typical dipole ESPAR antenna in which a voltage bias line is connected to each of the parasitic elements 120 and a negative pattern 126 of each of the parasitic elements 120 are connected to a negative region 114 of the active element 110 (VSWR) and copying (DIV) for a dipole ESPAR antenna using a common ground as a dipole ESPAR antenna using a common ground connected by the connection pattern 134b and a connection pattern 134b composed of a quarter-wave meander strip line according to the present invention, Pattern.

5, the radius R of the active element 110 is 5 mm, the side substrate 122 of the parasitic element 120 has a relative dielectric constant of 4.3, a thickness of 0.8 mm, and a parasitic element The positive pattern 124 and the negative pattern 126 of the dipole ESPAR antenna 120 have a thickness D of 0.35 mm and a width W of 9 mm and the total length of the dipole ESPAR antenna is 52 mm. The predetermined distance B between the elements 120 is a standing wave ratio (VSWR) calculated with a length of lambda / 16 of 7.6 mm and a radiation pattern calculated at a center frequency of 2.45 GHz.

5 compares the VSWR characteristics calculated for a typical dipole ESPAR antenna, a common ground dipole ESPAR antenna, and a meander line common ground dipole ESPAR antenna, respectively.

That is, the connection pattern 134b to which a negative voltage is applied to at least one of the negative region 114 and the negative pattern 126 shown in FIGS. 1 to 4 is applied to the negative region 114 and the negative pattern 126 to improve the characteristics of the VSWR and satisfy a ratio of 1.5: 1 or less in a 40 MHz channel bandwidth.

Here, FIG. 6 compares the calculated radiation pattern for each of the general dipole ESPAR antenna, the common ground dipole ESPAR antenna and the meander line common ground dipole ESPAR antenna shown in the figure.

Here, the radiation pattern is a value calculated at a center frequency of 2.45 GHz, the gain of the common ground dipole ESPAR antenna is 4.6 dBi, and the gain of the meander line common ground dipole antenna is 5.6 dBi.

The meander line common-ground dipole ESPAR antenna has a smaller front-to-back ratio than a common dipole ESPAR antenna and a common dipole ESPAR antenna, and the gain is also as high as 1 dBi.

The reactances of the parasitic elements 120 used to form the pattern shown in Fig. 6 may be 0.75 pF for two adjacent ones and 3.7 pF for the other two adjacent to each other.

Fig. 7 shows a plurality of patterns calculated by varying the reactance of the parasitic element 120 in the calculated plural patterns shown in Fig.

That is, FIG. 7 is a radiation pattern at 2.45 GHz of the meander line common ground dipole ESPAR antenna, where the calculated gain may be 5.6 dBi.

In addition, the meander line common ground dipole ESPAR antenna can change the reactance of the parasitic element 120 by a specific amount of the capacitance to realize the electronic beam steering.

First, the reactance for forming the radiation pattern shown in Fig. 7 is shown in Table 1 below.

The first parasitic element The second parasitic element Third parasitic element The fourth parasitic element First radiation pattern 3.7 pF 0.75pF 0.75pF 3.7 pF Second copy pattern 0.75pF 0.75pF 3.7 pF 3.7 pF Third copy pattern 0.75pF 3.7 pF 3.7 pF 0.75pF Fourth copy pattern 3.7 pF 3.7 pF 0.75pF 0.75pF

The four parasitic elements 120 referred to in FIGS. 1 and 4 can form the first to fourth radiation patterns shown in FIG. 7 when the reactance is varied as shown in [Table 1].

It will be understood by those skilled in the art that various changes in form and details may be made therein without departing from the spirit and scope of the invention as defined in the appended claims. It will be possible.

Claims (10)

An active element formed of a cylindrical dipole structure divided into a positive region and a negative region spaced apart from the positive region; And
And a flat dipole structure divided into a negative pattern electrically connected to the negative region and a positive pattern electrically connected to the negative pattern, wherein at least one side of the case in which the active element is inserted and disposed And a parasitic element formed on the dipole ESPAR antenna. The method according to claim 1,
Further comprising a variable element soldered to the positive pattern and the negative pattern such that a reactance of the parasitic element is variable. The method of claim 2,
The variable element comprises:
A dipole ESPAR antenna, a varactor diode. The method according to claim 1,
The parasitic element includes:
A dipole ESPAR antenna in which the positive pattern and the negative pattern are formed by copper on a substrate having a predetermined relative dielectric constant. The method of claim 4,
Wherein:
The dipole ESPAR antenna is an FR-4 material having the relative dielectric constant of 4.1 to 4.4. The method of claim 4,
The thickness of the positive pattern and the negative pattern is preferably,
0.031 mm to 0.37 mm,
The width of the positive pattern and the width of the negative pattern,
7 mm to 10 mm dipole ESPAR antenna. The method according to claim 1,
Further comprising a coaxial cable for applying a positive voltage and a negative voltage to the active element,
Wherein the negative region comprises:
The coaxial cable is inserted and brought into contact with the negative voltage,
Wherein the positive region is a non-
And the coaxial cable inserted in the negative region is contacted to apply the positive voltage. The method of claim 7,
The active element includes:
Dipole ESPAR antenna spaced from the parasitic element by 7.3 mm to 7.8 mm. The method according to claim 1,
Further comprising a rear substrate on which a connection pattern connecting the negative region and the negative pattern is formed. The method of claim 9,
The connection pattern
A dipole ESPAR antenna, a quarter-wave meander strip line.

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