KR102488591B1 - Leakage wave antenna with reconfigurable beam steering - Google Patents

Abstract

The present invention relates to a leaky wave antenna capable of steering a beam, comprising: a dielectric substrate; a plurality of microstrip conductors disposed in parallel on the dielectric substrate; a plurality of variable elements mounted between the respective microstrip conductors to adjust a beam steering angle of a high frequency signal radiated through the plurality of microstrip conductors; and a DC bias voltage supply unit for applying a DC bias voltage of a predetermined pattern to the plurality of variable elements through the plurality of microstrip conductors.

Description

Leakage wave antenna with beam steering {LEAKAGE WAVE ANTENNA WITH RECONFIGURABLE BEAM STEERING}

The present invention relates to a leaky wave antenna, and more particularly, to a leaky wave antenna capable of beam steering at a fixed frequency.

A leaky wave antenna has a wide bandwidth, wide directivity, and high radiation efficiency, and has characteristics in that a beam steering angle of the antenna changes according to an operating frequency. Such a leaky wave antenna may be implemented through a waveguide structure or a microstrip structure.

A leaky wave antenna can obtain a radiation pattern using a floquet mode theorem applied to a periodically arranged unit cell structure. That is, in a leaky wave antenna having a periodic structure, if only the current distribution in one unit cell is known, the current distribution in each unit cell is the same except for the phase difference, so it is easy to know the current distribution of the entire structure. Electromagnetic waves radiated in space can be calculated through the current distribution. This means that an efficient leaky wave antenna can be designed if only one unit cell characteristic is known.

A modulated surface reactance antenna is a type of leaky wave antenna having a periodic structure. When the surface reactance of the antenna is configured to have a periodic distribution, the propagation characteristics of electromagnetic waves traveling along the surface can be easily expressed by equations. The fact that it can be expressed has been theoretically proven. In addition, it is known in academia that a modulated surface reactance antenna can control a beam steering angle using surface reactance having a periodic structure.

Recently, various methods for adjusting the beam steering angle of a surface reactance antenna modulated at a fixed frequency have been proposed, but have various limitations. For example, the conventional methods have a problem that the control area of the surface reactance is limited and the beam steering angle control area is not very wide. In addition, conventional methods have a problem in that an imbalance occurs in a beam steering angle region because the control of the beam steering angle of the antenna is possible only discretely and the difference is not uniform.

The present invention aims to solve the foregoing and other problems. Another object is a leaky wave antenna capable of adjusting at least one of a modulation period and an average surface reactance value of surface reactance having a periodic structure by controlling a DC bias voltage applied to one or more variable elements disposed between each microstrip conductor. is in providing

Another object is to provide a leaky wave antenna capable of actively controlling a beam steering angle of the antenna by adjusting at least one of a surface reactance modulation period and an average surface reactance value at a fixed frequency.

According to one aspect of the present invention to achieve the above or other object, a dielectric substrate; a plurality of microstrip conductors disposed in parallel on the dielectric substrate; a plurality of variable elements mounted between the respective microstrip conductors to adjust a beam steering angle of a high frequency signal radiated through the plurality of microstrip conductors; and a DC bias voltage supply unit for applying a DC bias voltage of a predetermined pattern to the plurality of variable elements through the plurality of microstrip conductors.

Effects of the leaky wave antenna according to embodiments of the present invention will be described as follows.

According to at least one of the embodiments of the present invention, by controlling the DC bias voltage applied to one or more variable elements disposed between each microstrip conductor of the leaky wave antenna, the modulation period and average surface of surface reactance having a periodic structure There is an advantage in that at least one of the reactance values can be easily adjusted.

In addition, according to at least one of the embodiments of the present invention, by adjusting at least one of the surface reactance modulation period and the average surface reactance value at a fixed frequency, there is an advantage in that the beam steering angle of the leaky wave antenna can be actively controlled. .

In addition, according to at least one of the embodiments of the present invention, a continuous beam steering region can be implemented based on a beam steering control method using an average surface reactance value of a leaky wave antenna, and at the same time, using a modulation period of a surface reactance Based on the beam steering control method, there is an advantage in implementing a wide beam steering range of the antenna.

In addition, according to at least one of the embodiments of the present invention, by combining the beam steering control method using the average surface reactance value and the beam steering control method using the modulation period of the surface reactance, the advantages/disadvantages of each method are appropriately converged. It has the advantage of being applicable to various fields, such as an antenna for a 5G base station that tracks a terminal user in real time and connects communication by using it, or an antenna for a radar that tracks and detects a target.

However, the effects that can be achieved by the leaky wave antenna according to the embodiments of the present invention are not limited to those mentioned above, and other effects not mentioned are common knowledge in the art to which the present invention belongs from the description below. will be clearly understandable to those who have

1 is a diagram showing the structure of a leaky wave antenna according to an embodiment of the present invention;
2 is a diagram showing the configuration of a DC bias voltage supply unit according to an embodiment of the present invention;
3 is a diagram showing a unit cell structure of a leaky wave antenna according to an embodiment of the present invention;
4 is a diagram showing a change in surface reactance of an antenna unit cell according to the capacitance of each varactor diode;
5 is a diagram showing a surface reactance modulation profile of a leaky wave antenna according to the present invention;
6 is a diagram referred to for explaining the relationship between the surface reactance distribution and the beam steering angle of the leaky wave antenna according to the present invention;
7 is a diagram referenced to explain a method of controlling an average surface reactance value of a leaky wave antenna according to the present invention;
8 is a diagram showing a dispersion diagram of a leaky wave antenna when the surface reactance control method of FIG. 7 is used;
9 is a diagram referenced to explain a method of controlling a surface reactance modulation period of a leaky wave antenna according to the present invention;
10 is a diagram showing a dispersion diagram of a leaky wave antenna when the surface reactance control method of FIG. 9 is used;
11 is a diagram referenced to explain a method of driving one of beam steering modes of a leaky wave antenna according to an embodiment of the present invention;
12 is a diagram showing a graph in which a radiation pattern of a leaky wave antenna is simulated and a graph in which the radiation pattern of the leaky wave antenna is actually measured according to an embodiment of the present invention.

Hereinafter, the embodiments disclosed in this specification will be described in detail with reference to the accompanying drawings, but the same or similar elements are given the same reference numerals regardless of reference numerals, and redundant description thereof will be omitted. The suffixes "module" and "unit" for components used in the following description are given or used together in consideration of ease of writing the specification, and do not have meanings or roles that are distinct from each other by themselves. In addition, in describing the embodiments disclosed in this specification, if it is determined that a detailed description of a related known technology may obscure the gist of the embodiment disclosed in this specification, the detailed description thereof will be omitted. In addition, the accompanying drawings are only for easy understanding of the embodiments disclosed in this specification, the technical idea disclosed in this specification is not limited by the accompanying drawings, and all changes included in the spirit and technical scope of the present invention , it should be understood to include equivalents or substitutes.

The present invention provides a leaky wave antenna capable of adjusting at least one of a modulation period and an average surface reactance value of surface reactance having a periodic structure by controlling a DC bias voltage applied to one or more variable elements disposed between each microstrip conductor. Suggest. In addition, the present invention provides a leaky wave antenna capable of actively controlling a beam steering angle of the antenna by adjusting at least one of a surface reactance modulation period and an average surface reactance value at a fixed frequency. Hereinafter, surface reactance as used herein is an imaginary part of surface impedance, and the surface impedance may be defined as a ratio of a tangential electric field to a tangential magnetic field of a surface wave. .

Hereinafter, various embodiments of the present invention will be described in detail with reference to the drawings.

FIG. 1 is a diagram showing the structure of a leaky wave antenna according to an embodiment of the present invention, and FIG. 2 is a diagram showing a configuration of a DC bias voltage supply unit shown in FIG. 1 .

1 and 2, a leaky wave antenna 100 according to an embodiment of the present invention is a periodically modulated surface reactance antenna, and includes a dielectric substrate 110, a radiation pattern unit 120, an input port ( 130), an output port 140, a plurality of variable elements 150, a plurality of RF choke inductors 160, and a DC bias voltage supply unit 170. The components shown in FIGS. 1 and 2 are not essential to implementing a leaky wave antenna, so the leaky wave antenna described herein may have more or fewer components than those listed above.

A dielectric substrate 110 may be disposed on a ground plane. The dielectric substrate 110 may be formed to have a predetermined permittivity and thickness.

A plurality of DC wire holes 115 may be formed in one region of the dielectric substrate 110 . The plurality of DC wire holes 115 may be formed through the dielectric substrate 110 to connect the DC bias voltage supply unit 170 and the plurality of microstrip conductors 122 with wires.

For example, each DC wire hole 115 may be formed to correspond to a position of each microstrip conductor 122 . In addition, each of the DC wire holes 115 may be arranged at equal intervals along the longitudinal direction of the leaky wave antenna 100, that is, along the X-axis direction of the drawing.

The radiation pattern part (or metal pattern part, 120) is formed on one surface of the dielectric substrate 110, and generates an RF signal (ie, electromagnetic wave) in a direction perpendicular to the dielectric substrate 110, that is, in the Z-axis direction of the drawing. can perform the function of radiating. The radiation pattern unit 120 may be formed of a metal material having excellent electrical conductivity, such as gold (Au), silver (Ag), copper (Cu), or aluminum (Al).

The radiation pattern unit 120 may include a first tapered structure 121 , a microstrip structure including a plurality of microstrip conductors 122 , and a second tapered structure 123 .

The first tapered structure 121 may be disposed between the input port 130 and the microstrip structure to transmit an RF signal received from the input port 130 to the microstrip structure. The first tapered structure 121 may be configured in a shape gradually tapering toward the input port 130 from the microstrip structure.

A plurality of microstrip conductors 122 may be disposed between the first tapered structure 121 and the second tapered structure 123 . In addition, the plurality of microstrip conductors 122 may be arranged in the longitudinal direction of the leaky wave antenna 100, that is, in the X-axis direction in the drawing. At this time, each microstrip conductor 122 may be arranged at equal intervals.

Each microstrip conductor 122 may be formed to extend by a predetermined distance in a direction perpendicular to the longitudinal direction of the leaky wave antenna 100, that is, in the Y-axis direction of the drawing. At this time, each microstrip conductor 122 may be formed to have the same or similar height, width and thickness to each other. Additionally, each microstrip conductor 122 may be placed parallel to an adjacent conductor.

The second tapered structure 123 may be disposed between the microstrip structure and the output port 140 to transmit an RF signal received from the microstrip structure to the output port 140 . The second tapered structure 123 may be configured in a shape gradually tapering toward the output port 140 from the microstrip structure. In addition, the second tapered structure 123 may be formed in a shape symmetrical to that of the first tapered structure 121 based on the microstrip structure.

An input port 130 is connected to one end of the first tapered structure 121 and inputs an RF signal received from an RF signal processor (not shown) to the first tapered structure 121 can be performed.

An output port 140 may be connected to one end of the second tapered structure 123 and output an RF signal received from the second tapered structure 123 .

The plurality of variable elements 150 are formed on the dielectric substrate 110 in a direction perpendicular to the longitudinal direction of the leaky wave antenna 100, that is, the X-axis direction in the drawing, and the longitudinal direction of the leaky wave antenna 100, that is, in the drawing. may be arranged in the Y-axis direction of That is, the plurality of variable elements 150 may be arranged in a matrix form on the dielectric substrate 110 .

The plurality of variable elements 150 may be mounted between the respective microstrip conductors 122 and perform a function of adjusting a beam steering angle of a radio frequency (RF) signal radiated through the microstrip conductors 122 . At this time, both ends of each variable element 150 may be electrically connected to two microstrip conductors 122 adjacent thereto. This is to receive DC bias voltage from the adjacent microstrip conductor 122 .

The plurality of variable elements 150 have a characteristic that capacitance is varied according to the DC bias voltage applied from the plurality of microstrip conductors 122 . Accordingly, the plurality of variable elements 150 generate the surface reactance distribution of the leaky wave antenna 100 according to the pattern of the DC bias voltage applied from the plurality of microstrip conductors 122, that is, the modulation period and average surface reactance of the surface reactance. You can perform a function to adjust the value. A varactor diode, graphene, or liquid crystal may be used as the variable element 150, but is not necessarily limited thereto. Hereinafter, in the present embodiment, for convenience of explanation, the use of a varactor diode as the variable element 150 will be described as an example.

A plurality of RF choke inductors 160 are connected to one end of a plurality of microstrip conductors 122 disposed adjacent to a plurality of DC wire holes 115, and an RF signal flowing through the plurality of microstrip conductors 122 It can perform a function of preventing a phenomenon from passing to the outside through the DC bias voltage application circuit.

The DC bias voltage supply unit 170 may perform a function of supplying a DC bias voltage to the plurality of microstrip conductors 122 . In this case, the DC bias voltage supply unit 170 may be electrically connected to the plurality of microstrip conductors 122 through wire connections with the DC wire holes 115 formed in the dielectric substrate 110 .

For example, as shown in FIG. 2 , the DC bias voltage supply unit 170 may include a plurality of DC voltage sources 171 , a plurality of switches 173 and a plurality of connectors 175 . Here, the plurality of DC voltage sources 171 may supply DC bias voltages of different sizes. The plurality of switches 173 may electrically connect or disconnect between the plurality of DC voltage sources 171 and the plurality of connectors 175 . The plurality of connectors 175 may connect wires connected to the plurality of switches 173 and wires connected to the plurality of DC wire holes 115 . Meanwhile, according to the embodiment, the plurality of connectors 175 may be omitted.

The leaky wave antenna 100 having the components 110 to 170 as described above may be expressed as a structure of a plurality of unit cells generating a periodic surface reactance distribution. A detailed description of each unit cell structure will be described later with reference to the drawings below.

3 is a diagram showing a unit cell structure of a leaky wave antenna according to an embodiment of the present invention.

Referring to FIG. 3 , the unit cell structure 200 of the leaky wave antenna 100 according to an embodiment of the present invention includes a dielectric substrate 110, and first and second portions formed on one surface of the dielectric substrate 110. Microstrip conductors 122a and 122b, first to fourth varactor diodes 150a to 150d mounted between the first and second microstrip conductors 122a and 122b, and the first and second microstrip conductors It may include first and second RF choke inductors 160a and 160b connected to one end of 122a and 122b.

The dielectric substrate 110 includes a first DC wire hole 115a for electrically connecting a DC bias voltage supply unit (not shown) and the first microstrip conductor 122a, and a DC bias voltage supply unit and a second microstrip conductor. A second DC wire hole 115b for electrically connecting between 122b may be included.

The first and second microstrip conductors 122a and 122b may be disposed in a direction perpendicular to the longitudinal direction of the leaky wave antenna 100, that is, parallel to the Y-axis direction in the drawing. The first and second microstrip conductors 122a and 122b may be spaced apart from each other by a predetermined distance.

The first and second microstrip conductors 122a and 122b may receive a DC bias voltage having a predetermined potential difference through the first and second DC wire holes 115a and 115b.

The first to fourth varactor diodes 150a to 150d may be disposed between the first microstrip conductor 122a and the second microstrip conductor 122b on the dielectric substrate 110 . In this case, the first to fourth varactor diodes 150a to 150d may be arranged in a direction perpendicular to the longitudinal direction of the leaky wave antenna 100, that is, in the Y-axis direction in the drawing. In addition, the first to fourth varactor diodes 150a to 150d may be arranged at equal intervals. This is to uniformly implement the surface reactance along the Y-axis direction of the unit cell 200 .

The first to fourth varactor diodes 150a to 150d have a potential between the first DC bias voltage applied from the first microstrip conductor 122a and the second DC bias voltage applied from the second microstrip conductor 122b. Depending on the car, the capacitance varies. In addition, the surface reactance of the corresponding unit cell 200 varies according to the capacitance change of the first to fourth varactor diodes 150a to 150d.

)는 아래 수학식 1을 통해 계산될 수 있다.For example, FIG. 4 is a graph showing the surface reactance range of a unit cell according to the capacitance of each varactor diode at a fixed frequency. As shown in FIG. 4 , it can be confirmed that the surface reactance of the unit cell 200 is determined according to the capacitance of each varactor diode. The surface reactance of the unit cell 200 (

) can be calculated through Equation 1 below.

x축 방향의 파수(wavenumber)이고,

는 자유 공간의 파수이고,

는 자유 공간의 파동 임피던스(wave impedance)임.here,

is the wavenumber in the x-axis direction,

is the wave number in free space,

is the wave impedance of free space.

As such, the surface reactance of each unit cell 200 may be adjusted according to a potential difference between the first and second DC bias voltages applied to the first to fourth varactor diodes 150a to 150d. In addition, the surface reactance of each unit cell 200 may determine the surface reactance distribution of the leaky wave antenna 100, that is, the modulation period of the surface reactance and the average surface reactance value.

Meanwhile, in this embodiment, four varactor diodes are exemplified in each unit cell, but it is not necessarily limited thereto, and more or less varactor diodes may be installed. It will be clear to those skilled in the art.

As described above, the leaky wave antenna according to an embodiment of the present invention controls the DC bias voltage applied to one or more variable elements disposed between each microstrip conductor to determine the modulation period of surface reactance having a periodic structure and At least one of the average surface reactance values can be adjusted. In addition, the leaky wave antenna 100 may actively control a beam steering angle of the antenna by adjusting at least one of a surface reactance modulation period and an average surface reactance value at a fixed frequency.

5 is a diagram showing a surface reactance modulation profile of a leaky wave antenna according to the present invention, and FIG. 6 is a diagram referenced to explain a relationship between a surface reactance distribution and a beam steering angle of a leaky wave antenna according to the present invention.

5 and 6, the leaky wave antenna 100 according to an embodiment of the present invention has a surface reactance profile in which the surface reactance value is periodically modulated along the length direction (ie, the X-axis direction) of the corresponding antenna. can be formed to have

The surface reactance of the leaky wave antenna 100 may be implemented as a surface reactance profile having a periodic pattern of various shapes, more preferably a surface reactance profile having a periodic pattern of a square wave shape (ie, a square wave modulated surface reactance profile). can be implemented as This is because when the surface reactance of the leaky wave antenna 100 is implemented in a periodic square wave shape, the surface reactance distribution of the corresponding antenna is simple, so that the beam steering angle of the antenna can be easily adjusted. Therefore, in the present embodiment, the surface reactance of the leaky wave antenna 100 is implemented in a periodic square wave shape as an example to be described.

The surface reactance Imag[Z _S ] of the leaky wave antenna 100 may be expressed as in Equation 2 below.

where X _S is the average surface reactance value, p is the modulation period of the standard reactance, and M is the modulation amplitude.

Meanwhile, according to the periodically modulated reactance surface theory, when an electromagnetic wave moves on a periodically modulated reactance surface in a leaky wave antenna, a plurality of spatial harmonics are generated according to the Flocket mode theory, and the Among the plurality of spatial harmonics, the -1st harmonic may be used as the main radiation mode of the antenna.

For example, as shown in FIG. 6 , the wave number in the longitudinal direction (ie, the X-axis direction) of the leaky wave antenna 100 may be expressed as Equation 3 below.

은 x축 방향에서의 n 차수 플로켓 고조파의 파수이고,

는 x축 방향에서의 기본 모드의 파수이고,

는 n 차수 플로켓 고조파의 위상 상수임.where n is the order of the Flocket harmonics, p is the modulation period of the surface reactance,

is the wave number of the nth order Floquet harmonic in the x-axis direction,

is the wave number of the fundamental mode in the x-axis direction,

is the phase constant of the nth order Flocket harmonic.

) 및 방사 각도(radiation angle,

)는 아래 수학식 4 및 5와 같이 정의될 수 있다. According to the Flocket mode theory, when the -1st harmonic is used as the main radiation mode of the leaky wave antenna 100 (ie, n=-1), the phase constant of the corresponding antenna 100

) and radiation angle,

) can be defined as in Equations 4 and 5 below.

는 평균 표면 리액턴스 값이고, p는 표준 리액턴스의 변조 주기이고,

는 자유 공간의 파수이고,

는 자유 공간의 파동 임피던스임.here,

is the average surface reactance value, p is the modulation period of the standard reactance,

is the wave number in free space,

is the wave impedance of free space.

)는 해당 안테나의 평균 표면 리액턴스 값(

)과 표준 리액턴스의 변조 주기(p)를 기반으로 결정될 수 있다. 따라서, 누설파 안테나(100)의 평균 표면 리액턴스 값(

) 및 표준 리액턴스의 변조 주기(p) 중 적어도 하나를 조절하여 안테나의 빔 조향각을 제어할 수 있다. 여기서, 누설파 안테나(100)의 평균 표면 리액턴스 값(

) 및 표준 리액턴스의 변조 주기(p)는 상술한 단위 셀들의 표면 리액턴스를 기반으로 조절될 수 있다. As defined in Equation 5 above, the radiation angle of the leaky wave antenna 100 (

) is the average surface reactance value of the antenna (

) and the modulation period (p) of the standard reactance. Therefore, the average surface reactance value of the leaky wave antenna 100 (

) and the modulation period (p) of the standard reactance can be adjusted to control the beam steering angle of the antenna. Here, the average surface reactance value of the leaky wave antenna 100 (

) and the modulation period p of the standard reactance may be adjusted based on the surface reactance of the unit cells described above.

7 is a diagram referenced to explain a method for controlling the average surface reactance value of a leaky wave antenna according to the present invention, and FIG. 8 is a dispersion diagram of a leaky wave antenna when the surface reactance control method of FIG. 7 is used. It is a drawing showing

)을 조절할 수 있다. 이때, 새로운 평균 표면 리액턴스 값(

)은 상술한 도 4의 표면 리액턴스 범위 내에서 조절될 수 있다. 누설파 안테나의 평균 표면 리액턴스 값 제어는 주요 방사 모드인 -1번째 플로켓 모드의 기울기 조절을 야기한다. First, as shown in FIG. 7, by adjusting the surface reactance of a plurality of unit cells constituting the leaky wave antenna 100, the average surface reactance value of the corresponding antenna 100 (

) can be adjusted. At this time, the new average surface reactance value (

) can be adjusted within the surface reactance range of FIG. 4 described above. Controlling the average surface reactance value of the leaky wave antenna causes the slope adjustment of the -1th Flocket mode, which is the main radiation mode.

)을 갖는 누설파 안테나의 -1번째 플로켓 모드(

)는 실선에 해당하고, 새로운 평균 표면 리액턴스 값(

)을 갖는 누설파 안테나의 -1번째 플로켓 모드(

)는 점선에 해당한다. For example, as shown in FIG. 8, the existing average surface reactance value (

) -1th Flocket mode of the leaky wave antenna (

) corresponds to the solid line, and the new average surface reactance value (

) -1th Flocket mode of the leaky wave antenna (

) corresponds to the dotted line.

)이 기존 평균 표면 리액턴스 값(

)보다 더 커진 경우, 새로운 평균 표면 리액턴스 값(

)을 갖는 누설파 안테나의 -1번째 플로켓 모드(

)의 기울기는 기존 평균 표면 리액턴스 값(

)을 갖는 누설파 안테나의 -1번째 플로켓 모드(

)의 기울기보다 더 작아진다. 반대로, 새로운 평균 표면 리액턴스 값(

)이 기존 평균 표면 리액턴스 값(

)보다 더 작아진 경우, 새로운 평균 표면 리액턴스 값(

)을 갖는 누설파 안테나의 -1번째 플로켓 모드(

)의 기울기는 기존 평균 표면 리액턴스 값(

)을 갖는 누설파 안테나의 -1번째 플로켓 모드(

)의 기울기보다 더 커진다. 이처럼, 누설파 안테나의 -1번째 플로켓 모드(

)의 기울기는 해당 안테나의 평균 표면 리액턴스 값에 반비례하는 것을 확인할 수 있다. By controlling the average surface reactance value of the leaky wave antenna, a new average surface reactance value (

) is the existing average surface reactance value (

), the new average surface reactance value (

) -1th Flocket mode of the leaky wave antenna (

) is the existing mean surface reactance value (

) -1th Flocket mode of the leaky wave antenna (

) becomes smaller than the slope of Conversely, the new average surface reactance value (

) is the existing average surface reactance value (

), the new average surface reactance value (

) -1th Flocket mode of the leaky wave antenna (

) is the existing mean surface reactance value (

) -1th Flocket mode of the leaky wave antenna (

) becomes larger than the slope of As such, the -1st floquet mode of the leaky wave antenna (

It can be seen that the slope of ) is inversely proportional to the average surface reactance value of the corresponding antenna.

)의 기울기가 해당 안테나의 평균 표면 리액턴스 값(

)에 따라 가변하기 때문에, 해당 방법은 연속적인 빔 스캐닝을 구현할 수 있다. 이때, 해당 방법을 통해 달성 가능한 빔 스캐닝 범위는 각 단위 셀의 표면 리액턴스 제어 범위에 의존한다. The -1st floquet mode of the leaky wave antenna (

) is the average surface reactance value of the antenna (

), the method can implement continuous beam scanning. At this time, the beam scanning range achievable through the corresponding method depends on the surface reactance control range of each unit cell.

9 is a diagram referenced to explain a method for controlling a surface reactance modulation period of a leaky wave antenna according to the present invention, and FIG. 10 is a diagram showing a dispersion diagram of a leaky wave antenna when the surface reactance control method of FIG. 9 is used. to be.

First, as shown in FIG. 9 , the surface reactance modulation period p of the corresponding antenna 100 may be adjusted by adjusting the surface reactance of a plurality of unit cells constituting the leaky wave antenna 100 . Controlling the surface reactance modulation period of the leaky wave antenna causes a shift of the -1th Flocket mode, which is the main radiation mode.

)는 실선에 해당하고, 새로운 변조 주기(p')를 갖는 누설파 안테나의 -1번째 플로켓 모드(

)는 점선에 해당한다.For example, as shown in FIG. 10, the -1th Flocket mode of a leaky wave antenna having an existing modulation period (p) (

) corresponds to a solid line, and the -1th Flocket mode of the leaky wave antenna having a new modulation period (p') (

) corresponds to the dotted line.

)는 기존 변조 주기(p)를 갖는 누설파 안테나의 -1번째 플로켓 모드(

)를 기준으로 우측 방향으로 수평 이동한다. 반대로, 새로운 변조 주기(p')가 기존 변조 주기(p)보다 더 작아진 경우, 새로운 변조 주기(p')를 갖는 누설파 안테나의 -1번째 플로켓 모드(

)는 기존 변조 주기(p)를 갖는 누설파 안테나의 -1번째 플로켓 모드(

)를 기준으로 좌측 방향으로 수평 이동한다. 이처럼, 누설파 안테나의 -1번째 플로켓 모드(

)의 이동 방향은 표면 리액턴스의 변조 주기가 길어지는지 혹은 짧아지는지 여부에 의해 결정되는 것을 확인할 수 있다.Through control of the surface reactance modulation period of the leaky wave antenna, when the new modulation period (p') becomes larger than the previous modulation period (p), the -1th Flocket mode of the leaky wave antenna having the new modulation period (p') (

) is the -1st floquet mode (of a leaky wave antenna having an existing modulation period p)

), it moves horizontally to the right. Conversely, when the new modulation period (p') is smaller than the existing modulation period (p), the -1th Flocket mode of the leaky wave antenna having the new modulation period (p') (

) is the -1st floquet mode (of a leaky wave antenna having an existing modulation period p)

), it moves horizontally to the left. As such, the -1st floquet mode of the leaky wave antenna (

It can be seen that the movement direction of ) is determined by whether the modulation period of the surface reactance becomes longer or shorter.

)가 해당 안테나의 표면 리액턴스 변조 주기(p)에 따라 수평 이동하기 때문에, 해당 방법은 불연속적인 빔 스캐닝을 구현할 수 있다. The -1st floquet mode of the leaky wave antenna (

) moves horizontally according to the surface reactance modulation period p of the corresponding antenna, the method can implement discontinuous beam scanning.

) 및 표면 리액턴스의 변조 주기(p)를 동시에 조절할 수 있음은 당업자에게 자명할 것이다. On the other hand, although not shown in the figure, by adjusting the surface reactance of a plurality of unit cells constituting the leaky wave antenna 100, the average surface reactance value of the corresponding antenna 100 (

) and the modulation period p of the surface reactance can be adjusted simultaneously.

11 is a diagram referenced to explain a method of driving one of beam steering modes of a leaky wave antenna according to an embodiment of the present invention. That is, FIG. 11(a) is a schematic diagram of the structure of a leaky wave antenna, FIG. 11(b) is a diagram showing a surface reactance distribution along the longitudinal direction of the leaky wave antenna, and FIG. 11(c) ) is a diagram showing surface reactance, varactor capacitance, and varactor applied voltage according to the order of varactor diodes.

First, as shown in (a) of FIG. 11, the leaky wave antenna 100 according to the present invention includes a plurality of microstrip conductors arranged in parallel and a plurality of varactor diodes arranged between the respective microstrip conductors. includes Hereinafter, in the present embodiment, for convenience of description, an example in which one varactor diode is installed between each microstrip conductor will be described. In addition, each varactor diode will be described as an example in which it is installed alternately in forward and reverse directions.

As shown in (c) of FIG. 11, when a predetermined low DC bias voltage is applied to the first to third varactor diodes, the capacitance of the first to third varactor diodes is changed to a high value. , and accordingly, the surface reactance of the first to third unit cells is adjusted to a high value. Conversely, when a predetermined high DC bias voltage is applied to the fourth to sixth varactor diodes, the capacitance of the fourth to sixth varactor diodes is changed to a low value, and thus the fourth to sixth unit cells. The surface reactance of is adjusted to a low value.

Similarly, when the same low DC bias voltage is applied to the 7th to 9th varactor diodes, the capacitance of the 7th to 9th varactor diodes is changed to a high value, and accordingly, the values of the 7th to 9th unit cells are changed. The surface reactance is tuned to a high value. Conversely, when the same high DC bias voltage is applied to the 10th to 12th varactor diodes, the capacitance of the 10th to 12th varactor diodes is changed to a low value, and accordingly, the 10th to 12th unit cells The surface reactance is adjusted to a low value.

In this way, when a DC bias voltage of a predetermined pattern is applied to a plurality of varactor diodes, the leaky wave antenna has a surface reactance distribution diagram as shown in FIG. Electromagnetic waves may be radiated at a corresponding beam steering angle. In addition, at least one of the modulation period and the average surface reactance value of the surface reactance distribution may be adjusted by controlling the DC bias voltage applied to the plurality of varactor diodes, and the beam steering angle of the leaky wave antenna may be controlled based on this. .

12 is a diagram illustrating a graph in which a radiation pattern of a leaky wave antenna is simulated and a graph in which a radiation pattern of a leaky wave antenna is actually measured according to an embodiment of the present invention. As shown in FIG. 12, as a result of comparing the radiation pattern located on the right side with the radiation pattern located on the left side, it is found that the radiation pattern of the actually measured leaky wave antenna operates similarly to that of the simulated leaky wave antenna. You can check. This antenna experiment was performed at a fixed frequency (eg, 5.8 GHz), and it can be confirmed that a beam steering angle range from -39 degrees to 53 degrees can be implemented through the corresponding simulation.

Meanwhile, although specific embodiments of the present invention have been described above, various modifications are possible without departing from the scope of the present invention. Therefore, the scope of the present invention is not limited to the described embodiments, and should be defined by not only the claims to be described later, but also those equivalent to these claims.

100: leaky wave antenna 110: dielectric substrate
120: radiation pattern unit 130: input port
140: output port 150: variable element
160: RF choke inductor 170: DC bias voltage supply

Claims (10)

dielectric substrate;
a plurality of microstrip conductors disposed in parallel on the dielectric substrate;
a plurality of variable elements mounted between the respective microstrip conductors to adjust a beam steering angle of a radio frequency (RF) signal radiated through the plurality of microstrip conductors; and
A DC bias voltage supply unit for applying a DC bias voltage of a predetermined pattern to the plurality of variable elements through the plurality of microstrip conductors,
Among the modulation period (p) and average surface reactance value (X _s ) of the surface reactance along the longitudinal direction of the leaky wave antenna, according to the pattern of the DC bias voltage applied from the plurality of microstrip conductors, the plurality of variable elements A leaky wave antenna characterized by adjusting at least one of them. According to claim 1,
The leaky wave antenna according to claim 1 , wherein the dielectric substrate includes a plurality of DC wire holes for connecting wires between the DC bias voltage supply unit and the plurality of microstrip conductors. According to claim 1,
The leaky wave antenna, characterized in that the plurality of microstrip conductors are arranged at equal intervals along the longitudinal direction of the leaky wave antenna. delete According to claim 1,
The leaky wave antenna, characterized in that the plurality of variable elements adjust the modulation period (p) and average surface reactance value (X _s ) of the surface reactance according to the pattern of the DC bias voltage. According to claim 1,
The plurality of variable elements control a beam steering angle of the high-frequency signal by adjusting at least one of a modulation period (p) and an average surface reactance value (X _s ) of the surface reactance at a fixed frequency Leaky wave, characterized in that antenna. According to claim 1,
The leaky wave antenna according to claim 1 , wherein the plurality of variable elements are arranged in a matrix form on the dielectric substrate. According to claim 1,
A leaky wave antenna, characterized in that any one of a varactor diode, graphene, and liquid crystal is used as the plurality of variable elements. According to claim 1,
and a plurality of RF choke inductors connected to one end of each of the microstrip conductors to prevent leakage of high-frequency signals flowing through the plurality of microstrip conductors toward the DC bias voltage supply unit. According to claim 1,
The leaky wave antenna according to claim 1 , wherein the DC bias voltage supply unit includes a plurality of DC voltage sources, a plurality of switches, and a plurality of connectors.

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