KR101037294B1 - High gain horn antenna with periodic thin wire structure - Google Patents

Abstract

The present invention relates to a horn-shaped antenna capable of transmitting and receiving electromagnetic waves, comprising: a waveguide, an antenna portion having a shape that is widened in an open direction in connection with the waveguide, and to improve antenna gain. In order to achieve this may be achieved by a horn antenna including a plurality of wires installed in the inner space of the antenna unit.

According to the present invention, the electromagnetic wave is minimized in a specific frequency band by a plurality of wires installed in the antenna unit, the antenna gain is improved when transmitting and detecting the electromagnetic wave.

Description

HIGH GAIN HORN ANTENNA WITH PERIODIC THIN WIRE STRUCTURE}

The present invention relates to an antenna capable of transmitting and receiving electromagnetic waves, and more particularly, to an antenna having a horn shape.

Horn antennas have been widely used as feed parts for radio astronomy and parabolic antennas in satellite communications. In addition, the horn antenna is equipped with miniaturized horn antennas for various situations and information. It is used to send and receive.

In developed countries, in particular, many efforts have been made to ensure the safe operation of vehicles by using various types of speed measuring devices using different microwaves and lasers, and proactive safety alarm detectors that can indicate various dangerous situations on the road. Doing

In particular, the United States legally recognizes the use of these speed meters and detectors, and a growing number of countries are pushing for legalization of their use worldwide.

The following frequency bands are used for the signals used in these measuring instruments and detectors.

Speed guns that detect vehicle speed to prevent overspeeding the vehicle include Ko-BAND (9.900 GHz), X-BAND (10.525 GHz), Ku-BAND (13.450 GHz), K-BAND (24.150 GHz), SUPERWIDE Ka-BAND (variably distributed between 33.000 and 36.000 GHz) and a laser (wavelength of 800 to 1100 nm) are used.

Here, the antenna transmits the electromagnetic waves in a specific direction or serves to detect electromagnetic waves transmitted from the outside in the direction of the antenna.

However, the general electromagnetic wave is radiated in the air and spreads in a direction different from the target direction. When transmitting an electromagnetic wave using an antenna, it may not be possible to transmit an electromagnetic wave having a satisfactory intensity in a desired direction. It was. In addition, even when receiving the electromagnetic wave, even if the electromagnetic wave is introduced into the opening of the horn antenna, there is a difficulty in analyzing a signal because a sufficient amount of electromagnetic wave does not flow into the detection device.

The present invention is to solve the above problems, to provide a horn antenna with improved antenna gain (antenna gain) in transmitting and receiving electromagnetic waves.

An object of the present invention as described above, the waveguide, the antenna portion having a shape widening in the open direction connected to the waveguide, and a plurality of installed in the inner space of the antenna unit to improve the antenna gain (antena gain) It can be achieved by a horn antenna comprising a wire.

In this case, the plurality of wires may form a space in which the effective dielectric constant becomes zero in electromagnetic waves of a specific frequency.

Here, the plurality of wires may be installed to be parallel to each other and should be parallel to the vibration direction of the electric field.

Specifically, the plurality of wires are preferably spaced apart at predetermined intervals in the inner space of the antenna unit.

The predetermined interval may be set differently according to the frequency of electromagnetic waves passing through the inner space of the antenna unit.

In addition, the plurality of wires may have a cross section of a predetermined size, and the size of the cross section may be configured to be set differently according to the frequency of electromagnetic waves passing through the inner space of the antenna unit.

Further, the plurality of wires may be formed as a circular wire having a predetermined radius, and the size of the radius may be set differently according to the frequency of electromagnetic waves passing through the inner space of the antenna unit.

On the other hand, the plurality of wires may be configured to be divided into a plurality of zones forming a space having a lower dielectric constant than the adjacent space for a plurality of electromagnetic waves having different frequencies.

The plurality of wires may be arranged at regular intervals in the corresponding zones, and the intervals in which the wires are disposed in the respective zones may be configured differently according to frequencies of corresponding electromagnetic waves.

In addition, the cross-sectional area of the wire installed in each zone may be configured differently according to the frequency of the corresponding electromagnetic wave.

According to the present invention, the electromagnetic wave can minimize the refraction of the electromagnetic wave at a specific frequency by a plurality of wires provided in the antenna unit, there is an effect that the antenna gain is improved during transmission and detection of the electromagnetic wave.

Hereinafter, with reference to the accompanying drawings will be described in detail a first preferred embodiment of a horn antenna according to the present invention. In this embodiment, a horn antenna for transmitting electromagnetic waves in a predetermined direction is used. However, the present invention is not limited thereto as one embodiment, and in addition, it is apparent that the present invention is applicable to all horn antennas that transmit and detect electromagnetic waves.

1 is an internal perspective view showing the inside of a horn antenna according to a first embodiment of the present invention.

As shown in FIG. 1, the horn antenna according to the present invention may include a waveguide 10 and an antenna unit 20 connected to the waveguide 10.

One end of the waveguide 10 may be connected to an electromagnetic wave transmitting device (not shown), and the other end may be connected to the antenna unit 20 to form a path for transmitting electromagnetic waves generated from the transmitting device. At this time, the electromagnetic wave may proceed to the antenna unit 20 along the inner surface of the waveguide 10.

The antenna unit 20 is configured in a horn shape having an opening formed at one side thereof. Specifically, the antenna unit 20 of the present embodiment may have a rectangular cross section and may be configured to gradually widen in the open direction. In addition, a ridge 30 may be formed inside the antenna unit 20 to reduce the total area of the horn antenna.

The antenna unit may be connected to the waveguide 10 to be installed to transmit an electromagnetic wave transmitted from the waveguide 10 in a predetermined direction, or may act as a path into which the electromagnetic wave transmitted from the outside enters the waveguide. .

In this case, the electromagnetic waves traveling along the waveguide 10 may be scattered in various directions while passing through the antenna unit 20. Therefore, even if the opening of the antenna unit 20 is provided in the direction of the transmission direction, the electromagnetic wave passing through the antenna unit 20 can travel in various directions, and only a part of the electromagnetic waves can reach the desired transmission direction. . Here, the antenna gain may be regarded as the degree of transmitting electromagnetic waves in the target direction.

In the present embodiment, the antenna gain is defined as described above in order to use the horn antenna for transmitting electromagnetic waves. However, in another embodiment, the antenna gain may be defined using how much electromagnetic waves transmitted from the outside can be detected. . However, in the case of the same horn antenna, the antenna gain when transmitting generally has a value corresponding to the antenna gain when detecting.

When the antenna gain is high, even if the target point is located at a long distance from the horn antenna, the signal can be easily transmitted and received, while when the antenna gain is low, it is difficult to accurately analyze the signal due to a lack of the amount of electromagnetic waves that are reached. Can be. Therefore, the present invention may include a plurality of wires 100 installed in the inner space of the antenna unit 20 to improve the antenna gain.

Hereinafter, the principle in which the antenna gain is improved by the plurality of wires 100 will be described in detail with reference to FIGS. 2 to 4.

FIG. 2 illustrates a traveling path of electromagnetic waves passing through objects having different dielectric constants.

,

는 매질 1, 2의 유전율이고,

는 전자기파의 입사각,

는 전자기파의 투과각을 의미한다.As shown in FIG. 2, electromagnetic waves passing through two media having the same permeability and different permittivity are represented by the following equation. here,

,

Is the permittivity of medium 1, 2,

Is the incident angle of electromagnetic waves,

Means transmission angle of electromagnetic wave.

는 0도에 근사할 수 있다.In this case, as shown in FIG. 2, if electromagnetic wave propagates into the air from a material having a permittivity of medium 1 close to zero (Epsilon Near Zero, hereinafter referred to as 'ENZ'), the transmission angle is independent of the incident angle of the electromagnetic wave.

Can be approximated to 0 degrees.

That is, when electromagnetic waves pass through the ENZ, most of the electromagnetic waves can proceed in approximation to the vertical direction of the ENZ surface. Therefore, by applying this property to the present invention, it is possible to induce the direction passing through the antenna portion in the target direction, thereby improving the antenna gain.

FIG. 3 is a schematic diagram illustrating a shape in which a plurality of wires are disposed in an inner space of the antenna unit in FIG. 1, and FIG. 4 is a graph illustrating permittivity of a space formed by the plurality of wires of FIG. 1 according to a frequency.

에 대하여 유전율이 0인 성질을 갖을 수 있다. 이를 플라즈마 주파수(

)라고 한다. 그리고, r에 해당하는 반지름을 갖고 각각 p 간격으로 배치되는 복수개의 와이어에 의한 플라즈마 주파수의 값은 아래에 의해 구해질 수 있다. (여기서, c는 빛의 속도를 의미함)In the present invention, a plurality of wires 100 may be installed in the inner space to adjust the dielectric constant of the inner space of the antenna unit. When the thin wires are arranged periodically in the air, the space formed by the wires has a specific frequency

It may have a property of having a dielectric constant of 0 with respect to. This is called the plasma frequency (

). And, the value of the plasma frequency by a plurality of wires each having a radius corresponding to r and arranged at p intervals may be obtained by the following. Where c is the speed of light

에 대한 상기 공간의 유전율

은 아래와 같다.And, as shown in Figure 4, other predetermined frequencies

Permittivity of the space for

Is shown below.

)에 대한 상기 공간의 유전율(

)은 상기 소정 주파수(

) 및 상기 플라즈마 주파수(

)의 크기에 따라 결정된다. 다시 말해, 복수개의 와이어(100)가 설치되는 공간은 각 와이어가 설치되는 간격(p) 및 반지름의 길이(r)를 제어하여, 소정 주파수(

)에 대한 공간의 유전율(

)을 조절할 수 있다.As such, the space in which the plurality of wires 100 are installed has a plasma frequency corresponding to each of the spaces p and the size r of the radius. And a predetermined frequency (

Permittivity of said space relative to

) Is the predetermined frequency (

) And the plasma frequency (

) Depends on the size. In other words, the space in which the plurality of wires 100 are installed controls the interval p at which each wire is installed and the length r of a radius, so that a predetermined frequency (

Permittivity of space for

) Can be adjusted.

In this case, when an electromagnetic wave having a frequency corresponding to the plasma frequency passes through a space where the plurality of wires 100 are installed, the electromagnetic waves may be configured to all proceed in a predetermined direction. In addition, even in the case of electromagnetic waves adjacent to the plasma frequency instead of the plasma frequency, a low dielectric constant is formed in comparison with the adjacent space, and thus, there is an advantage in that the width of the electromagnetic waves is dissipated while passing therethrough.

In the above equation, the case where the wire 100 has a circular cross section has been described as an example, but similar effects may be obtained even when a wire having a shape other than the circular cross section is used. In this case, however, the dielectric constant with respect to the plasma frequency or the predetermined frequency of the space may be determined by the size of the cross section.

Therefore, in the present invention, it is possible to control the dielectric constant of the inner space by using a plurality of wires in the inner space of the antenna portion, and thus it is possible to control the directivity of the electromagnetic wave passing through the antenna portion.

Specifically, as shown in FIG. 3, a plurality of wires 100 may be installed inside the antenna unit 20. At this time, the interval (p) and the cross section of the wire, each wire is installed can be determined in consideration of the size of the specific frequency used by the horn antenna. Here, the specific frequency may refer to a frequency of a band serving as a signal among frequency bands of electromagnetic waves transmitted and received through the horn antenna according to the present embodiment. Therefore, when designing the wire arrangement, the spacing and cross-sectional size of each wire with respect to the specific frequency may be set by using Equations 1 and 2 described above.

In this embodiment, the plurality of wires 100 may be installed inside the antenna unit 20. At this time, the plurality of wires 100, as shown in Figure 3, using a circular wire of this r of the predetermined radius r, each wire may be formed to be spaced apart by the distance between the adjacent wire and p.

At this time, the plurality of wires 100 are preferably arranged to constitute a plurality of rows and a plurality of columns. If the plurality of wires 100 are arranged to form a single row or a single column, the phenomenon of changing the dielectric constant for a specific frequency may not appear properly.

In this embodiment, the plurality of wires are along the width of the antenna unit 20 so that all electromagnetic waves passing through the antenna unit 20 can pass through all of the sections in which the plurality of wires 100 are formed. ) Are arranged at regular intervals p. In the waveguide 10, a plurality of rows are formed by forming columns at intervals p in the direction of the opening of the antenna unit 20. In this case, the plurality of wires preferably constitute a sufficient number of rows. However, as a result of the experiment, when the waveguide 10 constitutes three or more rows in the open direction of the antenna unit 20, satisfactory results were obtained.

Here, the plurality of wires 100 are preferably installed in a direction perpendicular to the direction in which the electromagnetic wave is transmitted and received. As described above, when an electromagnetic wave passes through a medium having a dielectric constant of zero, the electromagnetic wave is projected in a direction perpendicular to the surface where the medium ends. In the present embodiment, the surface where the dielectric constant closes to zero ends corresponds to a surface formed by a row of wires disposed on the outermost side, and each wire may be installed in a direction perpendicular thereto considering the direction in which the electromagnetic waves are transmitted and received. Can be. In this case, since the opening of the antenna unit 20 is generally formed in a direction in which electromagnetic waves are transmitted and received, in this case, the plurality of wires 100 may be parallel to the opened surface.

As described above, in this embodiment, the plurality of wires 100 are arranged to form a square. However, the arrangement shape is only one embodiment and the present invention is not limited thereto. In addition, the wires 100 may be arranged in various other forms. In this case, however, the equation for obtaining the plasma frequency or the shape of the graph in which the dielectric constant changes with respect to the frequency may vary.

Hereinafter, an experiment in which the change in the antenna gain is measured using the horn antenna according to the present embodiment will be described.

FIG. 5 shows simulation results of gain variation according to frequencies of four types of horn antennas. In this case, all four types of horn antennas used horn antennas having ridges 30.

FIG. 5A shows a change in gain of a horn antenna in which the length L of the antenna part is 40 mm and the wire is not provided in the antenna part. And (B) shows the gain change of the horn antenna where L is 26.92 mm and a wire is not provided in an antenna part. In addition, (C) shows the gain change of the horn antenna in which a plurality of wires of L of 26.92 mm and a radius r of 0.25 mm are arranged in three rows at regular intervals inside the antenna unit. And (D) shows the gain change of the horn antenna in which a plurality of wires having a radius of 26.92 mm and a radius r of 0.30 mm are arranged in three rows at regular intervals inside the antenna unit.

When comparing (A) and (B) with reference to FIG. 5, it can be seen that the antenna gain is lower in each frequency band when the length of the antenna portion (B) is shorter than that of (A). This generally indicates that the larger the antenna, the higher the gain.

However, in the case of adjusting the permittivity of the internal space by installing a plurality of wires 100 inside as shown in (C) and (D), although the size of the antenna is the same as (B), in a specific frequency band (A It is possible to obtain an antenna gain similar to that of a large antenna such as).

In addition, (C) and (D) have a high gain in a specific frequency band compared to having a low gain in most frequency bands compared to (B), it is preferable to selectively transmit or receive electromagnetic waves according to the frequency band It can show that it is possible.

In addition, (C) and (D) shows that the frequency band for obtaining the maximum gain is different, so that the plasma frequency band can be adjusted by controlling the size of the cross-sectional area of the wire.

In the above, the configuration of the horn antenna for increasing the antenna gain with respect to one specific frequency has been described, but the present invention may configure the horn antenna for increasing the antenna gain with respect to a plurality of frequencies.

To this end, the plurality of wires may be configured to have two or more plasma frequencies by adjusting them to have a different arrangement than the square, but hereinafter, a separate embodiment in which the dielectric constant of two frequencies may be reduced by using the square arrangement. Explain. However, the same name and the same reference numerals are used for the components common to the previous embodiment, and common descriptions will be omitted to avoid duplication.

6 is an internal sectional view showing an internal cross section of the horn antenna according to the second preferred embodiment of the present invention.

In the present embodiment, a plurality of wires 100 may also be installed inside the antenna unit 20. In this case, the plurality of wires 100 may be divided into a plurality of zones according to the spacing of the wires or the size of the cross section of the wires. Here, as described above, different plasma frequencies are formed according to the spacing of the wires and the size of the cross section of the wires. Thus, each zone can serve to lower the dielectric constant for different frequencies.

For example, as shown in FIG. 6, the plurality of wires may be divided into two zones D1 and D2. The zone D1 can be arranged in a square at intervals of P1 using a wire having a radius of r1. And, the D2 zone can be arranged in a square at intervals of P2 using a wire having a radius of r2.

In this case, the D1 zone and the D2 zone have different plasma frequencies ω₁ and ω₂, so that the dielectric constant can be configured to have a lower permittivity than the adjacent spaces for frequencies of different bands. At this time, it is preferable that the D1 and D2 are sequentially disposed along the direction in which the electromagnetic waves are transmitted and received so that all the electromagnetic waves passing through the antenna portion can pass through each zone.

In this case, the horn antenna may simultaneously use a frequency band of the K band (eg, 24.150 GHz) and the Ka band (eg, 36 GHz). In this case, it is possible to design a combination of r2 and P2 so that the frequency corresponding to the K band forms the plasma frequency ω₂ in the D2 region using the above equations (1) and (2). In the D1 region, it is possible to design a combination of r1 and P1 so that the frequency corresponding to the Ka band forms the plasma frequency ω₁.

Therefore, in the present embodiment, when electromagnetic waves of the K band and the Ka band are simultaneously transmitted from the waveguide, the electromagnetic waves corresponding to the Ka band are formed at the outermost side of the D1 region while passing through the D1 region having a dielectric constant close to zero for the corresponding frequency. It is possible to proceed in the dispensing direction while transmitting in the direction perpendicular to the wire row. This is because the dielectric constant of 0 may have the same projection angle for all incident angles.

The electromagnetic wave corresponding to the K band enters the D1 region while passing through the D2 region having a dielectric constant close to zero with respect to the corresponding frequency, and transmitting perpendicularly to the row of wires formed at the outermost side of the D2 region. The D1 region may not be close to zero in permittivity for the K band. However, even in this case, when the wire row formed on the outermost side of the D2 zone and the wire row formed on the outermost side of the D1 zone are parallel, the incident angle is formed to be close to zero. It is possible to travel in the dispensing direction while passing through the wire rows in the vertical direction.

Therefore, according to the present embodiment, it is possible to configure a horn antenna that can improve antenna gain for frequencies in two areas.

However, in this embodiment, the configuration to improve the antenna gain for the two frequency domains by providing two zones, but according to the present invention a plurality of frequency domains having a plurality of zones are designed differently It is of course also possible to configure to improve the antenna gain with respect to.

Meanwhile, in the present embodiment, wires having different cross-sectional areas are arranged at different intervals in each zone, but it is also possible to alternatively use only one of the two variables.

1 is an internal perspective view showing the inside of a horn antenna according to a first embodiment of the present invention.

FIG. 2 illustrates a traveling path of electromagnetic waves passing through objects having different dielectric constants.

3 is a schematic diagram illustrating a shape in which a plurality of wires are disposed in an inner space of the antenna unit in FIG. 1.

4 is a graph illustrating permittivity of a space in which a plurality of wires of FIG. 1 are formed according to frequency.

5 is a graph showing a change in gain according to the frequencies of four types of horn antennas.

6 is an internal sectional view showing an internal cross section of the horn antenna according to the second preferred embodiment of the present invention.

Claims (13)

wave-guide; An antenna unit connected to the waveguide and having a shape widening in an open direction; And, It is installed in the inner space of the antenna unit, and includes a plurality of wires disposed in a direction perpendicular to the path for transmitting and receiving electromagnetic waves through the antenna unit, The space in which the plurality of wires are formed is divided into a plurality of zones forming a space having a lower dielectric constant than a space adjacent to a plurality of electromagnetic waves having different frequencies. delete delete delete delete delete delete delete delete The method of claim 1, The plurality of wires are arranged at regular intervals in the region, the spacing in which the wires are arranged in each region is different depending on the frequency of the corresponding electromagnetic wave. The method of claim 1, The horn antenna, characterized in that the cross-sectional area of the wire installed in each zone is different depending on the frequency of the corresponding electromagnetic wave. The method of claim 1, The plurality of zones are horn antenna, characterized in that arranged sequentially in the direction in which electromagnetic waves are transmitted and received. wave-guide; An antenna unit connected to the waveguide and having a shape widening in an open direction; And, Is installed in the inner space of the antenna unit, and includes a plurality of wires arranged in parallel with the open surface of the antenna unit, The space in which the plurality of wires are formed includes a first zone forming a space having a lower dielectric constant than the space adjacent to the first frequency and a second zone forming a space having a lower dielectric constant than the space adjacent to the second frequency. Horn antenna, characterized in that.

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