KR101129231B1 - Antenna structure capable of switching feed line - Google Patents

Abstract

 There is disclosed an antenna structure capable of switching to a feeder line of an antenna for selectively switching a feeder line for supplying power to an antenna so that only an antenna having a desired resonance frequency radiates electromagnetic waves. To this end, a feeding line switching network of an antenna including a pair of antennas, a first line and a second line connected to the pair of antennas, and an input signal line receiving a frequency signal is provided. By using the feeder line switching network of the antenna according to the present invention, it is possible to switch the feeder line through the circuit network in which the length of the transmission line is changed, thereby simplifying the structure of the feeder line switching network and reducing the cost.

Description

TECHNICAL FIELD [0001] The present invention relates to an antenna structure capable of switching to a feeder line.

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an antenna structure, and more particularly, to an antenna structure capable of switching to a feeder line of an antenna that selectively switches a feeder line for supplying power to an antenna and radiates electromagnetic waves only with an antenna having a desired resonance frequency will be.

Currently, various multimedia service environments such as mobile terminals and wireless network environments are rapidly increasing worldwide. With the increasing trend of various multimedia service environments, it is required to provide various services using electromagnetic waves.

In particular, there is a growing demand for a RE-CONFIGURABLE ANTENNA system that can actively change antenna beam shape characteristics in accordance with a radio propagation environment that changes with time using a plurality of antennas.

Such an antenna system means an antenna system having the ability to radiate radio waves only at some desired frequency, to change the polarization of the radiated wave, or to change the pattern of the radiation beam. In order to operate such an antenna system, it is only necessary to control a plurality of antennas, and semiconductor switching diodes are mainly used to control each of these antennas.

However, in the case of the antenna system adopting the semiconductor switching diode which is used conventionally, since a semiconductor switching diode is adopted for controlling each antenna, a direct current bias circuit for driving these diodes and a direct current Additional components and circuits such as capacitors must be involved. This causes a problem that the switching network for controlling each antenna is structurally complicated and the cost is increased. Further, there arises a problem that it is difficult to integrate circuits in a very high frequency or millimeter wave frequency band.

Accordingly, it is required to solve the problems caused by adoption of current semiconductor switching diodes, that is, to increase the complexity and cost of the circuit, and to develop a technology that can effectively integrate the circuit.

Therefore, it is an object of the present invention to provide a transmission line network having an odd multiple of 1/4 wavelength instead of a separate semiconductor switching element for switching to an antenna feed line, thereby simplifying the structure of a feeder line switching network, And it is an object of the present invention to provide an antenna structure capable of switching to a feeder line which can significantly improve the complexity of a network by allowing a plurality of antennas to be disposed spatially freely.

According to an aspect of the present invention, there is provided an antenna comprising: a pair of antennas having different resonance frequencies; A first line and a second line respectively connected to a pair of antennas for supplying high-frequency power to the pair of antennas; And an input signal line connected to a portion where the first line and the second line to which the frequency signal is applied are connected to each other.

Since an antenna structure capable of switching the feed line according to the present invention can be used to construct a switching network by changing the length of a transmission line, an antenna feed line using an existing semiconductor diode or the like as an active element is more costly than a switching network. And the integration of the circuit can be achieved very effectively.

And, by using the above-described structure, the radiation from a plurality of antennas can be selectively controlled, so that the shape of the electron beam emitted from the antennas can be automatically controlled. In addition, even when two frequency bands to be switched are very close to each other, it is possible to operate effectively, and the arrangement shape of a plurality of antennas can be freely adjusted spatially so that various beam patterns can be formed.

In particular, the use of a directional coupler with a backward meta-transmission line can increase the degree of isolation between the respective antennas, and thus is highly utilized in the construction of a reconfigurable antenna system.

Hereinafter, an antenna structure capable of switching to a feed line according to an embodiment of the present invention will be described in detail with reference to the drawings.

An antenna structure capable of switching to a feed line of the present invention selectively passes or blocks electromagnetic waves applied through a common feed line for supplying high frequency power to a pair of antennas or antennas having different resonance frequencies, And more particularly to a switching network capable of selectively operating only an antenna having a desired resonance frequency according to initial design purposes.

Hereinafter, each component will be described in detail with reference to the drawings.

FIG. 1 is an equivalent circuit diagram illustrating an antenna structure capable of switching to a feeder line according to an embodiment of the present invention. FIG. 2 is a structural view illustrating an antenna structure capable of switching to a feeder line according to an embodiment of the present invention .

1 and 2, an antenna structure capable of switching to a feeder line according to the present embodiment includes a pair of antennas 1 and 2 having a resonance frequency, a pair of antennas 1 and 2, A first line 3 and a second line 4 respectively connected to a pair of antennas 1 and 2 for supplying a high frequency power, a first line 3 and a second line 3 to which a frequency signal is applied, 4 connected to each other are connected to each other.

(안테나(1)),

(안테나(2))의공진주파수를 가지고, 상기 한 쌍의 안테나(1)(2)의 공진주파수는 서로 다른 것이 바람직하다. The pair of antennas (1) and (2)

(Antenna 1),

(Antenna 2), and the resonance frequencies of the pair of antennas 1 and 2 are preferably different from each other.

의 공진주파수를 가지는 안테나(1)와 연결되도록 하고, 제2 선로(4)는

의 공진주파수를 가지는 안테나(2)와 각각 연결되도록 형성하는 것이 바람직하다.The first line 3 and the second line 4 are preferably connected to the pair of antennas 1 and 2 having different resonance frequencies. More specifically, the first line 3

And the second line 4 is connected to the antenna 1 having the resonance frequency of

And the antenna 2 having the resonance frequency of the resonance frequency.

The lengths of the first line 3 and the second line 4 connected to the pair of antennas 1 and 2 are respectively set to 1/4 wavelength of the resonance frequency of the connected antennas 1 and 2, (1x, 3x, 5x ...) length of the length. The first line 3 and the second line 4 are connected to the antennas 1 and 2, respectively. However, the first line 3 and the second line 4 are not necessarily perpendicularly bent at 90 ° as shown in the figure.

The lengths of the first line 3 and the second line 4, which are adjacent to each other with respect to the resonance frequencies of the pair of antennas 1 and 2 and are related to the wavelength lengths of the respective resonance frequencies, The longer the length, the better the switching characteristics.

The input signal line 5 serves to apply a frequency so that a frequency signal can flow to the pair of antennas 1 and 2 through the first line 3 and the second line 4. [ For this purpose, the input signal line 5 is preferably connected to a portion where the first line 3 and the second line 4 are in contact with each other.

In the case of the feed-through switching network of the antenna configured as described above, the input impedance of the upper input stage Z ₁ is

이고,

ego,

The input impedance of the input stage (Z ₂₎ of the lower side is

이다.

to be.

에서 첫 번째 암(arm)의 길이는

이므로

가 되므로

이 된다. 그러나 두 번째 암(arm)의 길이는

이므로

가 되므로

이 된다. 여기서

로 놓으면

로 되어져 순허수 값을 갖게 된다. If the lengths of the lines (the first line and the second line) are 1/4 wavelength of the resonance frequency, the input impedance of each line will be as follows. First,

The length of the first arm in

Because of

Will be

. However, the length of the second arm is

Because of

Will be

. here

To

And has a pure imaginary value.

, 그리고 부하 임피던스

가 모두 실수인 경우에

은 실수 값을 갖게 되지만,

은 순 허수 값을 갖게 된다. 특히

로 두 주파수가 근접하게 되면

이므로

가 되고, 따라서

가 된다. 이 경우에

로 수렴하면,

가 되므로 개방회로가 된다. The characteristic impedance of the line

, And load impedance

Is all a mistake

Will have a real value,

Will have a net imaginary value. Especially

When the two frequencies are close to each other

Because of

And therefore

. In this case

As shown in FIG.

So that it becomes an open circuit.

이며, 이상적으로 안테나가 공진주파수에서는

로 순 실수 값을 갖으며, 안테나가 해당 공진주파수 이외에서 또는 공간으로 에너지를 방사하지 못하게 될 경우에는

로 순허수 값을 갖는다. Here, the input impedances of the respective antennas 1 and 2 are

And ideally the antenna is at the resonant frequency

The antenna has a net real number value, and when the antenna can not radiate energy to or from the space other than the resonance frequency

Lt; / RTI >

의 길이는 각각의 공진주파수

의 파장 길이의 1/4에 해당하는 길이이다. In addition, a 1/4 wavelength line

The length of each resonance frequency

Lt; 4 >

인 경우에

으로 순저항 값을 가지고

는 순허수로 된다. 또한, 상기 입력단에 인가되는 신호의 주파수가

로 두 개의 안테나의 공진주파수가 근접되어 있으면,

이므로 주파수

에서 하단의 안테나는 대략 1/4 파장 길이의 단락회로가 되어

이므로 개방회로로 동작된다.The frequency of the signal applied to the input terminal

in case of

With a net resistance value

Becomes a net imaginary number. Further, the frequency of the signal applied to the input terminal

If the resonance frequencies of the two antennas are close to each other,

Therefore,

The antenna at the lower end becomes a short circuit of approximately 1/4 wavelength length

So that it operates as an open circuit.

3 to 4 are equivalent circuit diagrams illustrating a switching operation principle of a circuit for explaining an antenna structure capable of switching to a feed line according to an embodiment of the present invention.

3 to 4, the operation concept of the antenna switching power supply circuit can be confirmed when the radiation resistance of each of the antennas 1 and 2 and the characteristic impedance of the line are 50 OMEGA. More In detail, the input frequency is f = f is _1, the second line (4) (arm 2 = off) that can be seen that the short-circuit, the input frequency f = f ₂ at the first track (3) (arm 1 = off) is short-circuited.

FIG. 5 is a Smith chart showing the reactance value of the equivalent input impedance of the antenna placed in the OFF state in the switching network of the antenna feeder lines of FIGS. 1 to 4. FIG.

즉, X→0의 조건이 만족되어져 보다 이상적인 스위치 회로로 작용할 수 있음을 확인할 수 있다.

인 경우에 off 되어진 선로는 이상적으로는 1/4 파장 길이의 단락회로가 되어

이므로 개방회로로 동작되나, 이 동작되는 한계주파수의 범위는 대략 40 % 정도까지도 가능하다. 즉 주파수

까지 스위칭 급전선로로 동작 되어진다. Referring to FIG. 5, the equivalent input impedance of the antenna placed in the OFF state in the network shown in FIG. 3 to FIG. 4 becomes closer to the midpoint of the Smith chart,

That is, it can be confirmed that the condition of X? 0 is satisfied, and it can act as a more ideal switch circuit.

The line that is turned off is ideally a short circuit of 1/4 wavelength length

However, the range of the operating limit frequency can be up to about 40%. That is,

To the switching power supply line.

6 is a structural view illustrating an antenna structure capable of switching to a feed line according to another embodiment of the present invention.

Referring to FIG. 6, the antenna structure capable of switching to the feed line of the present invention may further include an open microstrip stub 6 and a microstrip line 7.

It is preferable that the open microstrip stub 6 is formed in parallel at the portions where the first line 3 and the second line 4 are joined to each other.

The open microstrip stub 6 is positioned in the middle of the first line 3 and the second line 4 so as to be in parallel with the both lines and the microstrip line 7 is connected to the first It is preferable that the line 3 and the second line 4 are formed in series in a portion where they are joined to each other. More specifically, the microstrip line 7 is preferably connected to the first line 3 and the second line 4 connected to the pair of antennas 1 and 2. That is, it is preferable that the first line 3 and the second line 4 are additionally formed between the portions where the first line 3 and the second line 4 are in contact with each other.

 The determination of the lengths of the open microstrip stub 6 and the microstrip line 7 can be performed by changing the reactance value of the input impedance of the antenna which has been changed due to the addition of the microstrip line 7 to the open microstrip stub 6, To be canceled by the reactance value generated by the reactance value.

That is, it is preferable that the open microstrip stub 6 or the short-circuit microstrip stub is formed to have a length that serves as an L-shaped matching circuit with the microstrip line 7.

However, if a network is formed through the open microstrip stubs 6 and the microstrip line 7 illustrated in the present invention, the spatial arrangement of the pair of antennas 1 and 2 can be more freely adjusted, It is possible to play a role of coordinating arrangement for suppressing coupling interference or the like between the adjacent pair of antennas 1 and 2 as much as possible.

Furthermore, a short-circuit type microstrip stub having a length of about 1/4 wavelength may be used in place of the open microstrip stub 6. [

인 경우의 도 6의 스위칭 동작 원리를 나타낸 등가회로도이다.Figures 7 to 8 illustrate an ideal case,

Is an equivalent circuit diagram showing the switching operation principle of Fig.

7, an open microstrip stub 6 and a microstrip line 7 of the same length are formed on an equivalent circuit at portions where the first line 3 and the second line 4 are joined to each other, It can be seen that parallel formation and serial susceptance are additionally formed.

로 되며, 안테나와 직접 연결되어진 선로는 인덕티브 리액턴스(inductive reactance)를 가지므로 이를 서셉턴스로 표현하면

로 되므로, 해당 안테나가 공진할 경우에는 선로의 총 서셉턴스 값은 영이 된다(

= 0).In this case, since the open microstrip stub 6 equivalently exhibits capacitive reactance, it can be expressed as a susceptance

, And the line directly connected to the antenna has an inductive reactance, which can be expressed as a susceptance

Therefore, when the antenna is resonant, the total susceptance value of the line becomes zero (

= 0).

FIG. 9 is a structural view showing another embodiment of an antenna structure capable of switching to the feed line of FIG. 6. FIG.

9, the antenna structure capable of switching to the feed line according to the present invention includes the pair of antennas 1 and 2, the first line 3 and the second line 4, the input signal line 5, An antenna structure (switching module 9) including an antenna structure (switching module 9) capable of switching to a feed line made up of an open microstrip stub 6 and a microstrip line 7, (Switching module 10) capable of switching to another feeder line that is the same as the antenna structure (switching module 10).

,

)는 서로 동일한 한 쌍의 안테나(

,

)를 채택하는 것이 바람직할 것이다.The pair of antennas (9, 10) included in each of the switching modules (9, 10)

,

Are connected to a pair of antennas

,

). ≪ / RTI >

And a power divider (8) for distributing power to each of the switching modules (9) and (10).

That is, by using the power distributor 8, it is possible to operate the four antennas, thereby freely adjusting the shape of the beam pattern radiated into the space from the antenna.

However, the power divider 8 is a general T-type divider having a low isolation between the ports, and when the power divider 8 is used as a wilkinson distributor, a resistor must be connected between each port There is a problem in that the spatial arrangement of the antennas is disadvantageous when arranging a plurality of antennas.

In order to solve such a problem, it is preferable that the power divider 8 is adopted as a reverse directional coupler 13 including a meta transmission line 12 having a negative refractive index.

10 is a structural view showing another embodiment of an antenna structure capable of switching to the feed line of FIG.

 10, an antenna structure capable of switching to a feed line according to the present invention includes an antenna structure (switching module 9) capable of switching to the feed line, an antenna structure (switching module 9) capable of switching to the feed line, (Switching module 10) capable of switching to the same one of the feeder lines (switching module 10) capable of switching to the other feeder line, and an antenna structure (switching module 10) And a directional coupler (hereinafter referred to as a reverse directional coupler) as a reverse CRLH (Composite Right and Left Handed) transmission line including a meta transmission line.

,

), 상기 한 쌍의 안테나에 고주파 전력을 공급하도록 한 쌍의 안테나와 각각 연결되는 제1 선로 및 제2 선로, 주파수 신호를 인가받는 상기 제1 선로 및 제2 선로가 서로 접합되는 부분에 연결되는 입력신호선로, 상기 제1 선로 및 제2 선로가 서로 접합되는 부분에 병렬로 형성되는 개방형 마이크로스트립 스터브 또는 단락형 마이크로스트립 스터브, 및 상기 제1 선로 및 제2 선로가 서로 접합되는 부분에 직렬로 형성되는 마이크로스트립 선로로 이루어진 급전선로 스위칭이 가능한 제1 안테나 구조체를 포 함하는 것이 바람직하다.That is, a pair of antennas having different resonance frequencies

,

), A first line and a second line connected to a pair of antennas for supplying high frequency power to the pair of antennas, and a first line and a second line to which a frequency signal is applied, An open microstrip stub or a short-circuit microstrip stub formed in parallel at an area where the first line and the second line are joined to each other as an input signal line, and an open microstrip stub or a short-circuit microstrip stub in series with the first line and the second line, And a first antenna structure capable of switching to a feeder line formed of a microstrip line formed therein.

,

), 상기 한 쌍의 안테나에 고주파 전력을 공급하도록 한 쌍의 안테나와 각각 연결되는 제1 선로 및 제2 선로, 주파수 신호를 인가받는 상기 제1 선로 및 제2 선로가 서로 접합되는 부분에 연결되는 입력신호선로, 상기 제1 선로 및 제2 선로가 서로 접합되는 부분에 병렬로 형성되는 개방형 마이크로스트립 스터브 또는 단락형 마이크로스트립 스터브, 및 상기 제1 선로 및 제2 선로가 서로 접합되는 부분에 직렬로 형성되는 마이크로스트립 선로로 이루어진 급전선로 스위칭이 가능한 제2 안테나 구조체를 포함하는 것이 바람직하다.And a pair of antennas having different resonance frequencies (

,

), A first line and a second line connected to a pair of antennas for supplying high frequency power to the pair of antennas, and a first line and a second line to which a frequency signal is applied, An open microstrip stub or a short-circuit microstrip stub formed in parallel at an area where the first line and the second line are joined to each other as an input signal line, and an open microstrip stub or a short-circuit microstrip stub in series with the first line and the second line, And a second antenna structure capable of switching to a feeder line formed of a microstrip line.

And a directional coupler including a meta transmission line having a negative refractive index to connect the first and second antenna structures capable of switching to the respective feed lines.

인 안테나(17)(18)에 각각 공급된다.More specifically, the power input through the input terminal 14, which is the center feed point, is divided into two halves and transmitted to the input port of the backward directional coupler 13 using the line 12 having a negative refractive index. Further, one half of the power transmitted to the backward directional coupler 13 passes through the pass-through port and reaches the resonance frequency

In antennas 17 and 18, respectively.

인 안테나(19)(20)로 공급된다.Further, a half of the remaining power transmitted to the input port of the reverse directional coupler 13 is a resonant frequency

In antenna 19 (20).

인 안테나(17)(18)에는 1/4 파장 길이의 전송선로(15)와 연결되고, 공진 주파수

인 안테나(19)(20)에는 1/4 파장 길이의 전송선로(16)가 연결되어 있어서, 입력단자(14)에 입사된 신호의 주파수가

인 경우에는 두 개의 안테나(17)(18)만 에너지 방사가 이루어지며, 주파수가

인 경우에는 다른 두 개의 안테나(19)(20)에서만 에너지 방사가 이루어진다.Accordingly,

The antenna elements 17 and 18 are connected to the transmission line 15 having a 1/4 wavelength length,

The transmission line 16 having a 1/4 wavelength length is connected to the in-plane antennas 19 and 20 so that the frequency of the signal input to the input terminal 14 is

, Only the two antennas 17 and 18 are energetically radiated, and the frequency

The energy is radiated only from the other two antennas 19 and 20.

The design and characteristics of the antenna switching power supply line using the above-described directional coupler 13 will be described below.

11 to 12 are current density distribution diagrams showing current density distributions on the antenna conductors varied by the switching action of FIG.

인 안테나 들을 이용해 하나의 스위칭 급전선로에 서로 인접한 공진주파수를 가지는 4개의 안테나를 배열하였다. 이렇게 배열된 각각의 안테나 도체 상에 흐르는 전류밀도를 측정한 결과, 주파수에 따라서 스위칭되는 안테나 급전선로의 특성에 의하여 선택적으로 2개의 안테나만이 동작하는 것을 확인 할 수 있다. 이에 따라서 본 발명의 스위칭 급전선로는 별도의 스위칭 소자를 사용하지 않고도 효과적으로 안테나의 방사 에너지를 제어할 수 있다.11 to 12, when the resonance frequencies of the two antennas are

Four antennas with resonant frequencies adjacent to each other were arranged on one switching power supply line. As a result of measuring the current density flowing on each of the antenna conductors arranged in this way, it is confirmed that only two antennas selectively operate due to the characteristic of the antenna feed line switched according to the frequency. Accordingly, the switching power supply line of the present invention can effectively control the radiant energy of the antenna without using a separate switching element.

Also, by using the directional coupler with the backward meta transmission line, it is possible to increase the degree of isolation between the antennas and to improve the utilization in the construction of the reconfigurable antenna system. The isolation between the antennas is shown in [Table 1].

[Table 1]

(GHz) 1.92 1.94 1.96 1.98 2.11 2.13 2.15 2.17 Isolation level [dB]

-17.47 -18.81 -19.89 -20.14 -21.06 -19.92 -18.78 -17.67

-22.00 -24.73 -27.77 -30.27 -18.53 -17.58 -17.12 -16.92

-21.16 -23.25 -24.31 -25.87 -20.21 -19.74 -19.57 -19.73

-18.78 -19.81 -20.05 -19.85 -25.93 -24.71 -23.09 -21.78

-24.75 -24.01 -23.37 -23.06 -29.64 -30.41 -30.99 -31.42

-23.48 -26.69 -30.24 -33.77 -19.00 -18.74 -18.91 -19.26

Referring to Table 1, the isolation characteristics of the antenna ports according to the angular frequencies of the antenna switching feed line using the reverse meta transmission line directional coupler are shown in Table 1, which shows a very high degree of isolation, It can be confirmed that it is very effective.

FIGS. 13 to 14 are views showing an antenna fabricated on the basis of the structural view of FIG. 10, FIGS. 15 to 18 show design values and measured values of return loss and input impedance values of the antennas of FIGS. 12 to 13 FIG.

13 to 14 illustrate a 2x2 microstrip array antenna using an antenna switching power supply line using an inverted meta transmission line directional coupler.

The reflection loss value and the input impedance value in the initial design of the 2 × 2 microstrip array antenna are shown in FIGS. 15 to 16, and the actual reflection loss value and the input impedance value of the designed 2 × 2 microstrip array antenna are shown in FIGS. It can be seen from FIG.

More specifically, the designed antenna showed 50.88 - j2.73Ω at 1.95 GHz and 43.71 - j7.07Ω at 2.140 GHz, but the resonance frequency was slightly changed due to manufacturing process errors in the fabricated antenna, The input impedance trajectory was also spaced from the perfect matching point, resulting in approximately 28 Ω at 1.95 GHz and 47 Ω at 2.140 GHz.

However, as a result of measurement of the radiation pattern of the fabricated antenna, 6.8 dBi at the center frequency of 1.95 GHz, 7.6 dBi at 2.14 GHz of the center frequency of the reception frequency band, and it is confirmed that the switching power feeding circuit of the antenna is operating satisfactorily can do. In addition, the efficiency of the antenna at each center frequency is as high as 76.48% and 80.23%, so that there is no problem in application of the actual communication system.

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 by the following claims It can be understood that.

1 is an equivalent circuit diagram illustrating an antenna structure capable of switching to a feed line according to an embodiment of the present invention.

2 is a structural view illustrating an antenna structure capable of switching to a feed line according to an embodiment of the present invention.

3 to 4 are equivalent circuit diagrams illustrating a switching operation principle of a circuit for explaining an antenna structure capable of switching to a feed line according to an embodiment of the present invention.

FIG. 5 is a Smith chart showing the reactance value of the equivalent input impedance of the antenna placed in the OFF state in the antenna structure capable of switching to the feed line of FIGS. 1 to 4. FIG.

6 is a structural view illustrating an antenna structure capable of switching to a feed line according to another embodiment of the present invention.

7 to 8 are equivalent circuit diagrams showing the switching operation principle of Fig.

FIG. 9 is a structural view showing another embodiment of an antenna structure capable of switching to the feed line of FIG. 6. FIG.

10 is a structural view showing another embodiment of an antenna structure capable of switching to the feed line of FIG.

11 to 12 are current density distribution diagrams showing the current density distribution on the antenna conductor changed by the switching operation of FIG.

13 to 14 are views showing an antenna manufactured on the basis of the structural view of FIG.

Figs. 15 to 18 are diagrams showing design values and measured values of the return loss value and the input impedance value of the antennas of Figs. 12 to 13. Fig.

BRIEF DESCRIPTION OF THE DRAWINGS

1, 2, 17, 18, 19, 20: antenna

3, 4, 15, 16: transmission line 5: input signal line

6: Open microstrip stub

7: Microstrip line

12: meta transmission line having a negative refractive index

13: reverse directional coupler 14: input terminal

Claims (5)

Different resonance frequencies (

,

A pair of antennas; A first line connected to the pair of antennas to supply high frequency power to the pair of antennas and having an odd multiple of a quarter wavelength or a quarter wavelength of a resonance frequency of the pair of antennas, 2 lines; And And an input signal line connected to a portion where the first line and the second line to which the frequency signal is applied are joined to each other, The first line

And the second line is connected to the antenna having the resonance frequency of

Wherein the antenna structure is connected to an antenna having a resonant frequency of the antenna. The method according to claim 1, An open microstrip stub or a short-circuit microstrip stub formed in parallel at a portion where the first line and the second line are joined to each other; And Further comprising a microstrip line formed in series at a portion where the first line and the second line are joined to each other. 3. The method of claim 2, Wherein the open microstrip stub or the short-circuit microstrip stub has a length that serves as an L-shaped matching circuit with the microstrip line. The method according to claim 1, The resonance frequency of the pair of antennas

,

)end

Wherein the antenna structure is capable of switching with a feeder line. delete

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