JP2007049213A - Antenna system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a small-sized and light weight antenna system that is operated over a wide frequency band and has an excellent reflection characteristic within a desired frequency band. <P>SOLUTION: The antenna system (sleeve antenna) comprises: a coaxial line 1 comprising an inner conductor and an outer conductor 2; a linear radiation conductor 3 connected at the tip of the coaxial line 1 to the inner conductor; two cylindrical sleeve conductors 6, 8 covering the outer conductor 2 of the coaxial line 1; a guard-like connection conductor 5 connected at the tip of the coaxial line 1 to the outer conductor 2 and the sleeve conductors 6; and a variable reactive element 7 for connecting the two sleeve conductors 6, 8. In this case, the sleeve antenna can be operated over a wide frequency band by regulating the variable capacitive element to change the frequency band at which a leakage current is to be blocked without increasing the distance between the two sleeve conductors 6, 8 and the outer conductor 2 of the coaxial line 1. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to an antenna device in which a variable reactance element is installed in a sleeve antenna, thereby making it possible to vary a frequency band for blocking a leakage current flowing in a feeder line and to obtain good reflection characteristics within a desired frequency band. .

  A generally well-known sleeve antenna will be described with reference to FIG. 1. A simple cylindrical sleeve conductor is not divided into two cylindrical sleeve conductors, but a cylindrical outer conductor of a coaxial line. Is provided outside. Of course, there is no variable reactance element connecting two cylindrical sleeve conductors. A conventional sleeve antenna fed by a coaxial line is fed by its inner conductor at the end of the coaxial line, and a linear conductor of about a quarter wavelength is connected to the inner conductor at the end of the coaxial line. A cylindrical sleeve conductor of a quarter wavelength length is connected to the cylindrical outer conductor of the coaxial line through the blade-shaped conductor of the sword at the end of the coaxial line. The conductor is a radiating element. The sleeve conductor has a function as a radiating element and a function of blocking leakage current flowing outside the outer conductor of the coaxial line. The sleeve conductor can prevent leakage current flowing outside the outer conductor of the coaxial line only in the vicinity of the frequency at which the length of the sleeve conductor becomes a quarter wavelength. When the distance between the sleeve conductor and the outer conductor of the coaxial line is increased, the characteristic impedance of the coaxial line constituted by the sleeve conductor and the outer conductor of the coaxial line is increased. Therefore, the frequency band in which the sleeve conductor can prevent the leakage current becomes wider as the distance between the sleeve conductor and the outer conductor of the coaxial line becomes larger, and becomes narrower as the distance becomes smaller.

  On the other hand, generally, when a dipole antenna is downsized, a frequency band in which impedance matching can be obtained becomes narrow. As a method for solving this problem, in a dipole antenna, a matching circuit including a variable reactance element is attached to a radiating element, and frequency tuning is performed by adjusting the value of the variable reactance element (see, for example, Patent Document 1). ).

JP-A-9-130132

  In order to use the sleeve antenna over a wide frequency band, it is necessary to block the leakage current flowing through the feeder line over the wide frequency band. For this purpose, it is necessary to increase the distance between the sleeve conductor and the feeder line, and there is a problem that the antenna device is increased in size.

  Further, when the sleeve antenna is downsized, the frequency band where impedance matching can be taken becomes narrow, and at the same time, the frequency band where leakage current can be blocked becomes narrow. In the method of attaching a matching circuit including a variable reactance element to a radiating element as is well known from the past, it is possible to reduce the size while maintaining a frequency band where impedance matching can be obtained, but a frequency band where leakage current can be prevented. Had the problem of becoming narrower.

  The present invention has been made to solve the above-described problems, and an object of the present invention is to provide an antenna device that operates over a wide frequency band, is small and lightweight, and has good reflection characteristics in a desired frequency band. To get.

  The antenna device according to the present invention includes a coaxial line composed of an inner conductor and an outer conductor, a radiation conductor connected to the inner conductor at a tip of the coaxial line, and first and first covers the outer conductor of the coaxial line. Two sleeve conductors, a connection conductor that connects the outer conductor and the first sleeve conductor at the end of the coaxial line, and a variable reactance element that connects the first and second sleeve conductors. is there.

  The antenna device according to the present invention operates over a wide frequency band, is small and lightweight, and has an effect of having good reflection characteristics in a desired frequency band.

  In the first embodiment, an example in which two cylindrical sleeve conductors are connected by a variable reactance element will be described. In the second embodiment, an example in which two flat sleeve conductors are connected by a variable reactance element will be described. Yes. In the third embodiment, an example in which two sleeve conductors are formed on the back surface of the dielectric substrate is described. In the fourth embodiment, an example in which two sleeve conductors are formed on the front and back surfaces of a dielectric substrate, respectively, is described.

  In the fifth embodiment, an example in which the cylindrical sleeve conductor and the outer conductor of the coaxial line are connected by a variable reactance element will be described. In the sixth embodiment, the flat sleeve conductor and the outer conductor of the coaxial line are connected to each other. An example in which is connected by a variable reactance element is described. In the seventh embodiment, an example is described in which a sleeve conductor is formed on a dielectric substrate, and the sleeve conductor and the ground conductor of the microstrip line are connected by a variable reactance element. In the eighth embodiment, when the sleeve conductor is formed on the dielectric substrate and the sleeve conductor and the ground conductor of the microstrip line are connected by the variable capacitance diode, an example of a method for controlling the reverse bias voltage of the variable capacitance diode is described. Explains. Further, in the ninth embodiment, the case where the dielectric substrate is covered with two cylindrical sleeve conductors is described, and in the tenth embodiment, the case where the dielectric substrate is covered with one cylindrical sleeve conductor is described. .

Embodiment 1 FIG.
An antenna apparatus according to Embodiment 1 of the present invention will be described with reference to FIG. 1 is a perspective view showing a configuration of an antenna apparatus according to Embodiment 1 of the present invention. In addition, in each figure, the same code | symbol shows the same or equivalent part.

  1, the antenna device (sleeve antenna) according to the first embodiment is connected to a coaxial line 1 composed of an inner conductor and an outer conductor 2, and an inner conductor of the coaxial line 1 at the end of the coaxial line 1, A linear conductor 3 having a length of about ¼ wavelength, a cylindrical first sleeve conductor 6 covering the outer conductor 2 of the coaxial line 1, and an outer conductor 2 and a first sleeve conductor of the coaxial line 1 The sword-like connection conductor 5 connecting the blade 6, the cylindrical second sleeve conductor 8 covering the outer conductor 2 of the coaxial line 1, and the first sleeve conductor 6 and the second sleeve conductor 8 are connected. A variable reactance element 7 is provided.

  The first sleeve conductor 6, the second sleeve conductor 8, and the outer conductor 2 of the coaxial line 1 constitute a coaxial line 9. Further, the linear conductor 3, the first sleeve conductor 6, and the second sleeve conductor 8 function as a radiating element.

  Next, the operation of the antenna device according to the first embodiment will be described with reference to the drawings.

  In FIG. 1, a linear conductor 3 is fed by a coaxial line 1. At this time, a part of the current flowing inside the outer conductor 2 of the coaxial line 1 leaks to the first sleeve conductor 6 at CC ′ in FIG.

  Here, the first sleeve conductor 6 and the second sleeve conductor 8 constitute an outer conductor 2 of the coaxial line 1 and a coaxial line 9. If the impedance of the coaxial line 9 viewed from AA ′ in FIG. 1 is made infinite by setting the variable reactance element 7 to an appropriate value, the outer conductor of the coaxial line 1 below AA ′ in FIG. 2 can be prevented from leaking.

  As described above, by adjusting the value of the variable reactance element 7, the leakage current flowing outside the outer conductor 2 of the coaxial line 1 below AA ′ in FIG. 1 can be prevented. Further, by changing the value of the variable reactance element 7, it is possible to change the frequency band that prevents the leakage current of the sleeve antenna.

Here, when the variable reactance element 7 is a variable capacitance element, the value of the variable capacitance element 7 for making the impedance of the coaxial line 9 viewed from AA ′ in FIG. 1 infinite is obtained. For simplicity, it is assumed that there is no loss in the coaxial line 9. The characteristic impedance of the coaxial line 9 is Z ₀ [Ω], the wave number is β [1 / m], the length of the first sleeve conductor 6 is L ₁ [m], and the value of the variable capacitance element 7 is C ₁ [F]. Assuming that the angular frequency is ω, the impedance Z _B [Ω] of the coaxial line 9 as viewed from BB ′ in FIG. 1 is as follows.

Further, the impedance Z _A [Ω] of the coaxial line 9 as viewed from AA ′ in FIG. 1 is as follows when the length of the second sleeve conductor 8 is L ₂ [m].

From equation (2), determining the value C ₁ of the variable capacitance element 7 to the impedance Z _A of the coaxial line 9 as seen over from AA 'Figure 1 is infinite. When the denominator of the equation (2) is 0, the following equation is obtained.

From the above equation (3), the value C ₁ of the variable capacitance element 7 at which the impedance of the coaxial line 9 viewed from AA ′ in FIG. 1 becomes infinite can be obtained at a desired frequency. That is, the value C ₁ of the variable capacitance element 7, by changing based on the equation (3), it is possible to change the frequency band to prevent leakage current of the antenna device.

  Further, when the value of the variable capacitance element 7 is reduced, the frequency for blocking the current is increased, but at the same time, the resonance frequency of the antenna is also increased. On the other hand, when the value of the variable capacitance element 7 is increased, the frequency for blocking the current is lowered, but at the same time, the resonance frequency of the antenna is also lowered. Therefore, by appropriately changing the value of the variable capacitance element 7 according to the frequency to be used, it is possible to prevent leakage current and always maintain a resonance state at the frequency at which the antenna input impedance is used. As described above, the operation of blocking the leakage current and the input impedance of the antenna apparatus are linked, and there is an advantage that the blocking of the leakage current and the impedance matching can be realized at the same time even if the frequency used is changed.

  Further, when the combined length of the first sleeve conductor 6 and the second sleeve conductor 8 is close to a quarter wavelength, the current flowing through the linear conductor 3 and the first and second sleeve conductors 6 , 8 produces the same current distribution as the half-wave dipole antenna, and the radiation pattern of the antenna device is the same as that of the half-wave dipole antenna.

  As described above, the value of the variable capacitance element 7 inserted between the two sleeve conductors 6 and 8 is changed to change the frequency band for preventing the leakage current, and at the same time, the resonance frequency of the antenna is changed in conjunction with the change. By doing so, it is possible to realize a sleeve antenna device having good reflection characteristics in a desired frequency band. By using this sleeve antenna device, the frequency band for preventing leakage current can be changed by adjusting the variable capacitance element 7 without increasing the distance between the sleeve conductors 6 and 8 and the outer conductor 2 of the coaxial line 1. Thus, the sleeve antenna can be operated over a wide frequency band. That is, there is an effect that it is possible to obtain a sleeve antenna device that operates over a wide frequency band, is small and light, and has good reflection characteristics in a desired frequency band.

Embodiment 2. FIG.
An antenna device according to Embodiment 2 of the present invention will be described with reference to FIGS. FIG. 2 is a perspective view showing a configuration of an antenna apparatus according to Embodiment 2 of the present invention.

  In FIG. 2, the antenna device (sleeve antenna) according to the second embodiment is connected to the coaxial line 1 composed of the inner conductor and the outer conductor 2, and the inner conductor of the coaxial line 1 at the end of the coaxial line 1, A linear conductor 3 having a length of about ¼ wavelength, an elongated ground conductor 10 having a certain width and connected in parallel to the outer conductor 2 of the coaxial line 1, and installed in parallel to the ground conductor 10 The strip-shaped first sleeve conductor 12, the strip-shaped second sleeve conductor 13 installed in parallel to the ground conductor 10, and the connection conductor 11 connecting the ground conductor 10 and the first sleeve conductor 12. A variable reactance element 7 for connecting the first sleeve conductor 12 and the second sleeve conductor 13 is provided.

  The first sleeve conductor 12, the second sleeve conductor 13, and the ground conductor 10 constitute a coplanar strip line 14.

  The ground conductor 10, the connection conductor 11, the first sleeve conductor 12, and the second sleeve conductor 13 are constituted by planar conductors. Therefore, this antenna device has an advantage that it is easy to make in a flat plate shape. Further, the connection conductor 11, the first sleeve conductor 12, the variable reactance element 7, and the second sleeve conductor 13 are installed one on each side of the ground conductor 10. The reactance values of the two variable reactance elements 7 are always the same value.

  Next, the operation of the antenna device according to the second embodiment will be described with reference to the drawings. FIG. 3 is a diagram showing the leakage current-frequency characteristics of the antenna device according to Embodiment 2 of the present invention. FIG. 4 is a Smith chart showing the measurement results of the input impedance of the antenna apparatus according to Embodiment 2 of the present invention. FIG. 5 is a Smith chart in which a part of FIG. 4 is enlarged.

  In FIG. 2, a linear conductor 3 is fed by a coaxial line 1. At this time, a part of the current flowing inside the outer conductor 2 of the coaxial line 1 leaks to the first sleeve conductor 12 at CC ′ in FIG.

  Here, the first sleeve conductor 12 and the second sleeve conductor 13 constitute a ground conductor 10 and a coplanar strip line 14. Since there are one first and second sleeve conductors 12 and 13 on each side of the ground conductor 10, there are two coplanar striplines 14 in this antenna device. By making the values of the two variable reactance elements 7 suitable at the same time so that the impedance of the coplanar stripline 14 seen from AA 'in FIG. 2 is infinite, it is lower than AA' in FIG. On the side, leakage current flowing through the outer side of the outer conductor 2 of the coaxial line 1 and the ground conductor 10 can be prevented.

  As described above, by simultaneously adjusting the values of the two variable reactance elements 7, the leakage current flowing outside the outer conductor 2 of the coaxial line 1 and the ground conductor 10 on the lower side of AA ′ in FIG. be able to. Further, by changing the values of the two variable reactance elements 7 at the same time, it is possible to change the frequency band for preventing the leakage current of the sleeve antenna device.

Here, consider a case where the variable reactance element 7 is a variable capacitance element. The value of the variable capacitance element 7 for making the impedance of the coplanar stripline 14 seen from AA ′ in FIG. 2 infinite is the characteristic impedance of the coplanar stripline 14 Z ₀ [Ω], and the wave number is β [1 / m] is obtained by the same equation as the equation (3) shown above. That is, the value C ₁ of the two variable capacitance elements 7, by changing simultaneously based on the equation (3), it is possible to change the frequency band to prevent leakage of the sleeve antenna.

  Further, when the combined length of the first sleeve conductor 12 and the second sleeve conductor 13 is close to a quarter wavelength, the current flowing through the linear conductor 3 and the first and second sleeve conductors 12 , 13 produce the same current distribution as that of the half-wave dipole antenna, and the radiation pattern of the antenna device is the same as that of the half-wave dipole antenna.

  Further, when the value of the variable capacitance element 7 is reduced, the frequency for blocking the current is increased, but at the same time, the resonance frequency of the antenna is also increased. On the other hand, when the value of the variable capacitance element 7 is increased, the frequency for blocking the current is lowered, but at the same time, the resonance frequency of the antenna is also lowered. Therefore, by appropriately changing the value of the variable capacitance element 7 according to the frequency to be used, it is possible to prevent leakage current and always maintain a resonance state at the frequency at which the antenna input impedance is used. As described above, the operation of blocking the leakage current and the input impedance of the antenna apparatus are linked, and there is an advantage that the blocking of the leakage current and the impedance matching can be realized at the same time even if the frequency used is changed.

For example, the wavelength of the center frequency of the desired frequency band is λ _c , the length of the first sleeve conductor 12 is about 0.17 λ _c , the length of the second sleeve conductor 13 is about 0.18 λ _c , and the ground conductor 10, the first sleeve conductor 12, the width of the second sleeve conductor 13 to about 0.017Ramuda _c, first, the distance between the second sleeve conductor 12 and the ground conductor 10 to about 0.008λ _c . The linear conductor 3 is a planar conductor having a length of about 0.25λ _c and a width of about 0.066λ _c .

At this time, the calculated value of the leakage current that flows outside the ground conductor 10 and the outer conductor 2 of the coaxial line 1 near AA ′ in FIG. 2 is shown in FIG. 3, the leakage current value I of the vertical axis is obtained by normalizing a current feed point, the frequency f _c of the horizontal axis is the center frequency of the desired frequency band. Each of the two circles, △, △, and X indicates the frequency range of each characteristic, and the first from the left of the △ mark and the second from the left of the ◯ mark are actually overlapped at the same frequency. It is drawn at a slightly separated position. The same applies to the first from the left of the x mark and the second from the left of the Δ mark. B is susceptance, and B = −ωC ₁ . It can be seen from FIG. 3 that the leakage current can be prevented to -10 dB or less in a desired frequency band by using three types of capacitance values of the variable capacitance element 7. Here, the specific bandwidth of the desired bandwidth is 48.4%.

  The measurement results of the input impedance of the antenna are shown on the Smith charts of FIGS. FIG. 5 is a measurement result of the reflection characteristic as viewed from CC ′ of the coaxial line 1 in FIG. 2, and the center is 75Ω. Further, the marks ◯, Δ, and X in FIG. 5 correspond to the frequency ranges indicated by marks ◯, Δ, and X in FIG. That is, in FIG. 5, when susceptance B = −0.0155 [S], the impedance locus only in the frequency range indicated by a circle in FIG. 3 is a solid line, and when susceptance B = −0.0052 [S], In FIG. 3, the impedance locus only within the frequency range indicated by Δ is indicated by a dotted line, and when the susceptance B = −0.0022 [S], the impedance locus only within the frequency range indicated by × in FIG. ing.

  FIG. 5 shows that even if the value of the variable capacitance element 7 is changed, the input impedance of the antenna can always be kept in a resonance state within a frequency range in which leakage current is blocked, and impedance matching can be realized. From the above, it can be confirmed that the operation of blocking the leakage current and the input impedance of the antenna apparatus are linked, and even if the frequency used changes, blocking of the leakage current and impedance matching can be realized at the same time.

  As described above, when the sleeve conductors 12 and 13 are formed in a flat plate shape, the value of the variable capacitance element 7 inserted between the sleeve conductors 12 and 13 is changed to change the frequency band for preventing the leakage current. At the same time, by changing the resonance frequency of the antenna in conjunction with each other, it is possible to realize a sleeve antenna device that has good reflection characteristics within a desired frequency band. If this sleeve antenna device is used, the sleeve antenna can be changed by changing the frequency band for preventing leakage current by adjusting the variable capacitance element 7 without increasing the distance between the sleeve conductors 12 and 13 and the ground conductor 10. Can be operated over a wide frequency band. That is, there is an effect that it is possible to obtain a sleeve antenna device that operates over a wide frequency band, is small and light, and has good reflection characteristics in a desired frequency band. Further, since the sleeve conductors 12 and 13 are constituted by planar conductors, there is an effect that it is possible to obtain an easy-to-make sleeve antenna device.

Embodiment 3 FIG.
An antenna apparatus according to Embodiment 3 of the present invention will be described with reference to FIG. FIG. 6 is a diagram showing a configuration of an antenna apparatus according to Embodiment 3 of the present invention. In the figure, (a) represents the front surface and (b) represents the back surface.

  In the third embodiment, a sleeve antenna is formed on a dielectric substrate and is fed by a microstrip line.

  In FIG. 6, in the antenna device according to the third embodiment, a strip conductor 16 of a microstrip line and a conductor 3 having a length of about a quarter wavelength are formed on the surface of a dielectric substrate 15. Yes.

  Further, on the back surface of the dielectric substrate 15, a microstrip line ground conductor 17, a first sleeve conductor 12 formed in parallel to the ground conductor 17, and a second sleeve formed in parallel to the ground conductor 17. A conductor 13, a connection conductor 11 that connects the ground conductor 17 and the first sleeve conductor 12, and a variable reactance element 7 that connects the first sleeve conductor 12 and the second sleeve conductor 13 are formed.

  The first sleeve conductor 12, the second sleeve conductor 13, and the ground conductor 17 of the microstrip line constitute a coplanar stripline 18.

  The ground conductor 17 of the microstrip line is an elongated planar conductor having a certain width, and the strip conductor 16 is an elongated planar conductor having a certain width thinner than the ground conductor 17. Since this antenna device is formed on the dielectric substrate 15, it can be produced by etching a double-sided copper foil substrate, and has the advantage that it is easy to produce. Further, the connection conductor 11, the first sleeve conductor 12, the variable reactance element 7, and the second sleeve conductor 13 are provided one on each side of the ground conductor 17 of the microstrip line. The reactance values of the two variable reactance elements 7 are always the same value.

  Next, the operation of the antenna device according to the third embodiment will be described with reference to the drawings.

  In FIG. 6, the conductor 3 is fed by a microstrip line. At this time, the current flowing through the back side of the ground conductor 17 of the microstrip line (the side where the ground conductor 17 is visible in FIG. 6 is referred to as the front side and the side where the ground conductor 17 is not visible is referred to as the back side) is shown in FIG. A part of the current leaks to the first sleeve conductor 12 at CC ′.

  Here, the first sleeve conductor 12 and the second sleeve conductor 13 constitute a ground conductor 17 and a coplanar strip line 18 of a microstrip line. Since the first and second sleeve conductors 12 and 13 are provided on both sides of the ground conductor 17 of the microstrip line, there are two coplanar striplines 18 in this antenna device. If the impedance of the coplanar stripline 18 as viewed from AA ′ in FIG. 6 is made infinite by setting the values of the two variable reactance elements 7 to appropriate values at the same time, it is lower than AA ′ in FIG. On the side, leakage current flowing on the surface side of the ground conductor 17 of the microstrip line can be prevented.

  As described above, by simultaneously adjusting the values of the two variable reactance elements 7, it is possible to prevent leakage current flowing on the surface side of the ground conductor 17 of the microstrip line below AA ′ in FIG. . Further, by simultaneously changing the values of the two variable reactance elements 7, it is possible to change the frequency band for preventing the leakage current of the sleeve antenna.

Here, consider a case where the variable reactance element 7 is a variable capacitance element. The value of the variable capacitance element 7 for making the impedance of the coplanar stripline 18 seen from AA ′ in FIG. 6 infinite is the characteristic impedance of the coplanar stripline 18 as Z ₀ [Ω], and the wave number as β [1 / m] is obtained by the same equation as the equation (3) shown above. That is, the value C ₁ of the two variable capacitance elements 7, by changing simultaneously based on the equation (3), it is possible to change the frequency band to prevent leakage of the sleeve antenna.

  Further, when the combined length of the first sleeve conductor 12 and the second sleeve conductor 13 is close to a quarter wavelength, the current flowing through the conductor 3 and the first and second sleeve conductors 12 and 13 are The flowing current creates the same current distribution as the half-wave dipole antenna, and the radiation pattern of the antenna device is the same as the radiation pattern of the half-wave dipole antenna.

  Further, when the value of the variable capacitance element 7 is reduced, the frequency for blocking the current is increased, but at the same time, the resonance frequency of the antenna is also increased. On the other hand, when the value of the variable capacitance element 7 is increased, the frequency for blocking the current is lowered, but at the same time, the resonance frequency of the antenna is also lowered. Therefore, by appropriately changing the value of the variable capacitance element 7 according to the frequency to be used, it is possible to prevent leakage current and always maintain a resonance state at the frequency at which the antenna input impedance is used. As described above, the operation of blocking the leakage current and the input impedance of the antenna apparatus are linked, and there is an advantage that the blocking of the leakage current and the impedance matching can be realized at the same time even if the frequency used is changed.

  As described above, when the antenna is formed on the dielectric substrate 15 and is fed by the microstrip line, the value of the variable capacitance element 7 inserted between the sleeve conductors 12 and 13 is changed to prevent leakage current. By changing the resonance frequency of the antenna in conjunction with changing the frequency band, it is possible to realize a sleeve antenna device that has good reflection characteristics within a desired frequency band. By using this sleeve antenna device, the frequency band for preventing leakage current can be changed by adjusting the variable capacitance element 7 without increasing the distance between the sleeve conductors 12 and 13 and the ground conductor 17 of the microstrip line. Thus, the sleeve antenna can be operated over a wide frequency band. That is, there is an effect that it is possible to obtain a sleeve antenna device that operates over a wide frequency band, is small and light, and has good reflection characteristics in a desired frequency band. In addition, since the antenna is formed on the dielectric substrate, it is possible to obtain an easy-to-make sleeve antenna device.

Embodiment 4 FIG.
An antenna apparatus according to Embodiment 4 of the present invention will be described with reference to FIG. FIG. 7 is a diagram showing a configuration of an antenna apparatus according to Embodiment 4 of the present invention. In the figure, (a) represents the front surface and (b) represents the back surface.

  In the fourth embodiment, the variable reactance element 7 is a variable capacitance diode.

  7, in the antenna device according to the fourth embodiment, on the surface of a dielectric substrate 15, a strip conductor 16 of a microstrip line, a conductor 3 having a length of about a quarter wavelength, and a strip conductor 16 are provided. The second sleeve conductor 13, the land conductor 19, the through hole 20, the variable-capacitance diode voltage control line (linear conductor) 21, and the high-frequency component blocking resistor (resistor) 22. The variable capacitance diode 7 that connects the land conductor 19 and the second sleeve conductor 13 is formed.

  Further, the ground conductor 17 of the microstrip line, the first sleeve conductor 12 formed in parallel to the ground conductor 17, and the ground conductor 17 and the first sleeve conductor 12 are connected to the back surface of the dielectric substrate 15. A connection conductor 11 and a through hole 20 are formed.

  The first sleeve conductor 12, the second sleeve conductor 13, and the ground conductor 17 of the microstrip line constitute a coplanar stripline 18.

  The land conductor 19 is connected to the first sleeve conductor 12 through the through hole 20. The second sleeve conductor 13 is connected to the land conductor 19 via the variable capacitance diode 7.

  The variable capacitance diode 7 is a diode whose capacitance value changes according to the applied reverse bias voltage. The reverse bias voltage is a DC voltage. Here, the reverse bias voltage is superimposed on the high frequency component of the microstrip line. Therefore, this antenna device has an advantage that it is not necessary to prepare a reverse bias voltage control line separately from the microstrip line. A voltage control line 21 is provided to apply a DC voltage superimposed on the microstrip line to the variable capacitance diode 7. In order to prevent a high frequency component from flowing through the voltage control line 21, there is a large gap between the voltage control line 21 and the strip conductor 16 of the microstrip line and between the voltage control line 21 and the second sleeve conductor 13. A resistor 22 is inserted. The resistor 22 is sufficiently smaller than the DC resistance of the variable capacitance diode 7. Further, since the voltage control line 21 is on the back side of the first sleeve conductor 12, it hardly affects the antenna characteristics of this apparatus.

  The connecting conductor 11, the first sleeve conductor 12, the through hole 20, the land conductor 19, the variable capacitance diode 7, the second sleeve conductor 13, and the voltage control line 21 are provided one on each side of the microstrip line. . The capacitance values of the two variable capacitance diodes 7 are always set to the same value.

  Next, the operation of the antenna device according to the fourth embodiment will be described with reference to the drawings.

  In FIG. 7, the conductor 3 is fed by a microstrip line. At this time, the current flowing through the back side of the ground conductor 17 of the microstrip line (the side where the ground conductor 17 is visible in FIG. 7 is referred to as the front side and the side where the ground conductor 17 is not visible is referred to as the back side) is shown in FIG. A part of the current leaks to the first sleeve conductor 12 at CC ′.

  Here, the first sleeve conductor 12 and the second sleeve conductor 13 constitute a ground conductor 17 and a coplanar strip line 18 of a microstrip line. Since the first and second sleeve conductors 12 and 13 are provided on both sides of the ground conductor 17 of the microstrip line, there are two coplanar striplines 18 in this antenna device. If the impedance of the coplanar stripline 18 as viewed from AA ′ in FIG. 7 is made infinite by adjusting the capacitance values by simultaneously setting the reverse bias voltages of the two variable capacitance diodes 7 to an appropriate value, It is possible to prevent a leakage current flowing on the surface side of the ground conductor 17 of the microstrip line below AA ′ in FIG.

  As described above, by simultaneously adjusting the reverse bias voltages of the two variable capacitance diodes 7, leakage current flowing on the surface side of the ground conductor 17 of the microstrip line below AA ′ in FIG. 7 is prevented. Can do. Further, by changing the values of the two variable capacitance diodes 7 at the same time, it is possible to change the frequency band for preventing the leakage current of the sleeve antenna.

  Further, when the value of the variable capacitance element 7 is reduced, the frequency for blocking the current is increased, but at the same time, the resonance frequency of the antenna is also increased. On the other hand, when the value of the variable capacitance element 7 is increased, the frequency for blocking the current is lowered, but at the same time, the resonance frequency of the antenna is also lowered. Therefore, by appropriately changing the value of the variable capacitance element 7 according to the frequency to be used, it is possible to prevent leakage current and always maintain a resonance state at the frequency at which the antenna input impedance is used. As described above, the operation of blocking the leakage current and the input impedance of the antenna apparatus are linked, and there is an advantage that the blocking of the leakage current and the impedance matching can be realized at the same time even if the frequency used is changed.

  Further, when the combined length of the first sleeve conductor 12 and the second sleeve conductor 13 is close to a quarter wavelength, the current flowing through the conductor 3 and the first and second sleeve conductors 12 and 13 are The flowing current creates the same current distribution as the half-wave dipole antenna, and the radiation pattern of the antenna device is the same as the radiation pattern of the half-wave dipole antenna.

  The resistor 22 may be an inductor. The through hole 20 may be a short pin.

  As described above, in the fourth embodiment, when the variable reactance element 7 is a variable capacitance diode, an example of the method for controlling the reverse bias voltage of the variable capacitance diode has been described. That is, if this antenna apparatus is used, since the reverse bias voltage is superimposed on the microstrip line, there is no need to prepare a separate reverse bias voltage control line, and the configuration is simplified. Further, the reverse bias voltage value of the variable capacitance diode 7 inserted between the two sleeve conductors 12 and 13 is changed to change the frequency band for preventing the leakage current, and at the same time, the resonance frequency of the antenna is changed in conjunction with it. By doing so, it is possible to realize a sleeve antenna device having good reflection characteristics in a desired frequency band. If this sleeve antenna device is used, the reverse bias voltage of the variable capacitance diode 7 can be adjusted to a frequency band that prevents leakage current without increasing the distance between the sleeve conductors 12 and 13 and the ground conductor 17 of the microstrip line. Therefore, the sleeve antenna can be operated over a wide frequency band. That is, there is an effect that it is possible to obtain a sleeve antenna device that operates over a wide frequency band, is small and light, and has good reflection characteristics in a desired frequency band.

Embodiment 5. FIG.
An antenna apparatus according to Embodiment 5 of the present invention will be described with reference to FIG. FIG. 8 is a perspective view showing a configuration of an antenna apparatus according to Embodiment 5 of the present invention.

  In FIG. 8, the antenna device (sleeve antenna) according to the fifth embodiment is connected to the coaxial line 1 composed of the inner conductor and the outer conductor 2 and the inner conductor of the coaxial line 1 at the end of the coaxial line 1. A linear conductor 3 having a length of about a quarter wavelength, a cylindrical sleeve conductor 23 covering the outer conductor 2 of the coaxial line 1, and a sword for connecting the outer conductor 2 and the sleeve conductor 23 of the coaxial line 1 A hook-shaped connection conductor 5 and a variable reactance element 25 that connects the sleeve conductor 23 and the outer conductor 2 of the coaxial line 1 are provided.

  The sleeve conductor 23 and the outer conductor 2 of the coaxial line 1 constitute a coaxial line 24. Further, the linear conductor 3 and the sleeve conductor 23 function as a radiating element.

  Next, the operation of the antenna device according to the fifth embodiment will be described with reference to the drawings.

  In FIG. 8, the linear conductor 3 is fed by the coaxial line 1. At this time, a part of the current flowing inside the outer conductor 2 of the coaxial line 1 leaks to the sleeve conductor 23 at CC ′ in FIG.

  Here, the sleeve conductor 23 constitutes the outer conductor 2 of the coaxial line 1 and the coaxial line 24. When the variable reactance element 25 is set to an appropriate reactance value so that the impedance of the coaxial line 24 viewed from AA ′ in FIG. 8 is infinite, the outside of the coaxial line 1 below AA ′ in FIG. Leakage current flowing outside the conductor 2 can be prevented.

  As described above, by adjusting the reactance value of the variable reactance element 25, it is possible to prevent a leakage current flowing outside the outer conductor 2 of the coaxial line 1 below AA ′ in FIG. Further, by changing the reactance value of the variable reactance element 25, it is possible to change the frequency band for preventing the leakage current of the sleeve antenna.

Here, when the variable reactance element 25 is a variable capacitance element, the capacitance of the variable capacitance element 25 for making the impedance of the coaxial line 24 viewed from AA ′ in FIG. 8 infinite is obtained. For simplicity, it is assumed that there is no loss in the coaxial line 24. In the sleeve conductor 23, the length from CC ′ to BB ′ in FIG. 8 is L ₁ ′ [m], and the length from BB ′ to AA ′ is L ₂ ′ [m]. Further, assuming that the characteristic impedance of the coaxial line 24 is Z ₀ ′ [Ω], the wave number is β ′ [1 / m], the capacitance of the variable capacitance element 25 is C ₂ [F], and the angular frequency is ω, AA in FIG. The impedance Z _A ′ [Ω] of the coaxial line 24 as viewed from above is as follows.

From equation (4), determining the capacitance _{C 2} of the variable capacitance element 25 the impedance _{Z A} of the coaxial line 24 viewed above the AA 'in FIG. 8 is infinite. When the denominator of the equation (4) is 0, the following equation is obtained.

The above equation (5), at a desired frequency, it is possible to obtain the capacitance C ₂ of the variable capacitance element 25 the impedance of the coaxial line 24 viewed above the AA 'in FIG. 8 is infinite. That is, the capacitance C ₂ of the variable capacitance element 25, by changing based on equation (5), it is possible to change the frequency band to prevent leakage current of the antenna device.

  In addition, when the capacitance of the variable capacitance element 25 is reduced, the frequency for blocking the current is increased, but at the same time, the resonance frequency of the antenna is also increased. On the contrary, when the capacitance of the variable capacitance element 25 is increased, the frequency for blocking the current is lowered, but at the same time, the resonance frequency of the antenna is also lowered. Therefore, by appropriately changing the capacitance of the variable capacitance element 25 in accordance with the frequency to be used, it is possible to prevent leakage current and always maintain a resonance state at the frequency at which the antenna input impedance is used. As described above, the operation of blocking the leakage current and the input impedance of the antenna apparatus are linked, and there is an advantage that the blocking of the leakage current and the impedance matching can be realized at the same time even if the frequency used is changed.

  Further, when the length of the sleeve conductor 23 is close to a quarter wavelength, the current flowing through the linear conductor 3 and the current flowing outside the sleeve conductor 23 form the same current distribution as that of the half-wave dipole antenna. The radiation pattern of the antenna device is the same as that of the half-wave dipole antenna.

  As described above, the capacitance of the variable capacitance element 25 inserted between the sleeve conductor 23 and the outer conductor 2 of the coaxial line 1 is changed to change the frequency band for preventing the leakage current, and at the same time, the antenna is interlocked. By changing the resonance frequency of the sleeve antenna device, it is possible to realize a sleeve antenna device having good reflection characteristics in a desired frequency band. By using this sleeve antenna device, the frequency band for preventing leakage current can be changed by adjusting the variable capacitance element 25 without increasing the distance between the sleeve conductor 23 and the outer conductor 2 of the coaxial line 1. The sleeve antenna can be operated over a wide frequency band. That is, there is an effect that it is possible to obtain a sleeve antenna device that operates over a wide frequency band, is small and light, and has good reflection characteristics in a desired frequency band.

Embodiment 6 FIG.
An antenna apparatus according to Embodiment 6 of the present invention will be described with reference to FIG. FIG. 9 is a perspective view showing a configuration of an antenna apparatus according to Embodiment 6 of the present invention.

  In FIG. 9, the antenna device (sleeve antenna) according to the sixth embodiment is connected to the coaxial line 1 composed of the inner conductor and the outer conductor 2 and the inner conductor of the coaxial line 1 at the end of the coaxial line 1. A linear conductor 3 having a length of about ¼ wavelength, an elongated ground conductor 10 having a certain width and connected in parallel to the outer conductor 2 of the coaxial line 1, and installed in parallel to the ground conductor 10 The strip-shaped sleeve conductor 26, the connection conductor 11 that connects the ground conductor 10 and the sleeve conductor 26, and the variable reactance element 25 that connects the sleeve conductor 26 and the ground conductor 10 are provided.

  The sleeve conductor 26 and the ground conductor 10 constitute a coplanar strip line 27.

  The ground conductor 10, the connection conductor 11, and the sleeve conductor 26 are constituted by planar conductors. Therefore, this antenna device has an advantage that it is easy to make in a flat plate shape. Further, the connection conductor 11, the sleeve conductor 26, and the variable reactance element 25 are installed one by one on both sides of the ground conductor 10. The reactance values of the two variable reactance elements 25 are always the same value.

  Next, the operation of the antenna device according to the sixth embodiment will be described with reference to the drawings.

  In FIG. 9, the linear conductor 3 is fed by the coaxial line 1. At this time, a part of the current flowing inside the outer conductor 2 of the coaxial line 1 leaks to the sleeve conductor 26 at CC ′ in FIG.

  Here, the sleeve conductor 26 constitutes the ground conductor 10 and the coplanar strip line 27. Since there is one sleeve conductor 26 on each side of the ground conductor 10, there are two coplanar striplines 27 in this antenna device. By making the reactance values of the two variable reactance elements 25 to appropriate values at the same time so that the impedance of the coplanar stripline 27 as viewed from AA ′ in FIG. On the lower side, the leakage current flowing through the outer side of the outer conductor 2 of the coaxial line 1 and the ground conductor 10 can be prevented.

  As described above, by simultaneously adjusting the reactance values of the two variable reactance elements 25, the leakage current flowing outside the outer conductor 2 of the coaxial line 1 and the ground conductor 10 below AA ′ in FIG. can do. Further, by changing the reactance values of the two variable reactance elements 25 at the same time, it is possible to change the frequency band for preventing the leakage current of the sleeve antenna device.

Here, consider a case where the variable reactance element 25 is a variable capacitance element. In the sleeve conductor 26, the length from CC ′ to BB ′ in FIG. 9 is L ₁ ′ [m], and the length from BB ′ to AA ′ is L ₂ ′ [m]. The capacitance of the variable capacitance element 25 for making the impedance of the coplanar stripline 27 seen from AA ′ in FIG. 9 infinite, the characteristic impedance of the coplanar stripline 27 is Z ₀ ′ [Ω], and the wave number is β ′ [1 / m] is obtained by the same formula as the formula (5) shown above. That is, by simultaneously changing the capacitance C2 of the _two variable capacitance elements 7 based on the equation (5), it is possible to change the frequency band for preventing the leakage current of the sleeve antenna.

  Further, when the length of the sleeve conductor 26 is close to a quarter wavelength, the current flowing through the linear conductor 3 and the current flowing through the sleeve conductor 26 produce the same current distribution as that of the half-wave dipole antenna. The radiation pattern is the same as that of the half-wave dipole antenna.

  In addition, when the capacitance of the variable capacitance element 25 is reduced, the frequency for blocking the current is increased, but at the same time, the resonance frequency of the antenna is also increased. On the contrary, when the capacitance of the variable capacitance element 25 is increased, the frequency for blocking the current is lowered, but at the same time, the resonance frequency of the antenna is also lowered. Therefore, by appropriately changing the capacitance of the variable capacitance element 25 in accordance with the frequency to be used, it is possible to prevent leakage current and always maintain a resonance state at the frequency at which the antenna input impedance is used. As described above, the operation of blocking the leakage current and the input impedance of the antenna apparatus are linked, and there is an advantage that the blocking of the leakage current and the impedance matching can be realized at the same time even if the frequency used is changed.

  As described above, when the sleeve conductor 26 is formed in a flat plate shape, the capacitance of the variable capacitance element 25 placed between the sleeve conductor 26 and the ground conductor 10 is changed to change the frequency band for preventing leakage current. At the same time, by changing the resonance frequency of the antenna in conjunction with each other, it is possible to realize a sleeve antenna device having good reflection characteristics in a desired frequency band. By using this sleeve antenna device, the sleeve antenna can be widened by changing the frequency band for preventing leakage current by adjusting the variable capacitance element 25 without increasing the distance between the sleeve conductor 26 and the ground conductor 10. It can be operated over a frequency band. That is, there is an effect that it is possible to obtain a sleeve antenna device that operates over a wide frequency band, is small and light, and has good reflection characteristics in a desired frequency band. Further, since the sleeve conductor 26 is composed of a planar conductor, it is possible to obtain an easy-to-make sleeve antenna device.

Embodiment 7 FIG.
An antenna apparatus according to Embodiment 7 of the present invention will be described with reference to FIG. FIG. 10 is a diagram showing a configuration of an antenna apparatus according to Embodiment 7 of the present invention. In the figure, (a) represents the front surface and (b) represents the back surface.

  In the seventh embodiment, a sleeve antenna is formed on a dielectric substrate and is fed by a microstrip line.

  In FIG. 10, in the antenna device according to the seventh embodiment, a strip conductor 16 of a microstrip line and a conductor 3 having a length of about a quarter wavelength are formed on the surface of a dielectric substrate 15. Yes.

  Also, on the back surface of the dielectric substrate 15, a microstrip line ground conductor 17, a sleeve conductor 26 formed parallel to the ground conductor 17, and a connection conductor connecting the microstrip line ground conductor 17 and the sleeve conductor 26. 11 and a variable reactance element 25 that connects the sleeve conductor 26 and the ground conductor 17 of the microstrip line are formed.

  The sleeve conductor 26 and the ground conductor 17 of the microstrip line constitute a coplanar stripline 27.

  The ground conductor 17 of the microstrip line is an elongated planar conductor having a certain width, and the strip conductor 16 is an elongated planar conductor having a certain width thinner than the ground conductor 17. Since this antenna device is formed on the dielectric substrate 15, it can be produced by etching a double-sided copper foil substrate, and has the advantage that it is easy to produce. Further, the connection conductor 11, the sleeve conductor 26, and the variable reactance element 25 are provided one on each side of the ground conductor 17 of the microstrip line. The reactance values of the two variable reactance elements 25 are always the same value.

  Next, the operation of the antenna device according to the seventh embodiment will be described with reference to the drawings.

  In FIG. 10, the conductor 3 is fed by a microstrip line. At this time, the current that has flowed through the back surface side of the ground conductor 17 of the microstrip line (the side where the ground conductor 17 is visible in FIG. 10B is referred to as the front surface side and the side that is not visible is referred to as the back surface side). 10, a part of the current leaks to the sleeve conductor 26.

  The sleeve conductor 26 constitutes a microstrip line ground conductor 17 and a coplanar strip line 27. Since there is one sleeve conductor 26 on each side of the ground conductor 17 of the microstrip line, there are two coplanar striplines 27 in this antenna device. By making the reactance values of the two variable reactance elements 25 to appropriate values at the same time so that the impedance of the coplanar stripline 27 seen from AA ′ in FIG. Leakage current flowing on the surface side of the ground conductor 17 of the microstrip line on the lower side can be prevented.

  As described above, by simultaneously adjusting the reactance values of the two variable reactance elements 25, it is possible to prevent leakage current flowing on the surface side of the ground conductor 17 of the microstrip line below AA ′ in FIG. it can. Further, by simultaneously changing the reactance values of the two variable reactance elements 25, it is possible to change the frequency band for preventing the leakage current of the sleeve antenna.

Here, consider a case where the variable reactance element 25 is a variable capacitance element. In the sleeve conductor 26, the length from CC ′ to BB ′ in FIG. 10 is L ₁ ′ [m], and the length from BB ′ to AA ′ is L ₂ ′ [m]. The capacitance of the variable capacitance element 25 for making the impedance of the coplanar stripline 27 seen from AA ′ in FIG. 10 infinite, the characteristic impedance of the coplanar stripline 27 is Z ₀ ′ [Ω], and the wave number is β ′ [1 / m] is obtained by the same formula as the formula (5) shown above. That is, by changing the capacitance C2 of the _two variable capacitance elements 25 at the same time based on Expression (5), it is possible to change the frequency band for preventing the leakage current of the sleeve antenna.

  Further, when the length of the sleeve conductor 26 is close to a quarter wavelength, the current flowing through the conductor 3 and the current flowing through the sleeve conductor 26 produce the same current distribution as that of the half-wave dipole antenna, and the radiation pattern of this antenna apparatus Is the same as the radiation pattern of a half-wave dipole antenna.

  In addition, when the capacitance of the variable capacitance element 25 is reduced, the frequency for blocking the current is increased, but at the same time, the resonance frequency of the antenna is also increased. On the contrary, when the capacitance of the variable capacitance element 25 is increased, the frequency for blocking the current is lowered, but at the same time, the resonance frequency of the antenna is also lowered. Therefore, by appropriately changing the capacity of the variable capacitance element 25 in accordance with the frequency to be used, it is possible to prevent leakage current and always keep the resonance state at the frequency at which the input impedance of the antenna is used. As described above, the operation of blocking the leakage current and the input impedance of the antenna apparatus are linked, and there is an advantage that the blocking of the leakage current and the impedance matching can be realized at the same time even if the frequency used is changed.

  As described above, when the antenna is formed on the dielectric substrate 15 and is fed by the microstrip line, the capacitance of the variable capacitance element 25 inserted between the sleeve conductor 26 and the ground conductor 17 of the microstrip line is changed. Thus, by changing the frequency band for preventing leakage current and simultaneously changing the resonance frequency of the antenna, a sleeve antenna device having good reflection characteristics in a desired frequency band can be realized. By using this sleeve antenna device, the frequency band for preventing leakage current can be changed by adjusting the variable capacitance element 25 without increasing the distance between the sleeve conductor 26 and the ground conductor 17 of the microstrip line. The sleeve antenna can be operated over a wide frequency band. That is, there is an effect that it is possible to obtain a sleeve antenna device that operates over a wide frequency band, is small and light, and has good reflection characteristics in a desired frequency band. In addition, since the antenna is formed on the dielectric substrate, it is possible to obtain an easy-to-make sleeve antenna device.

Embodiment 8 FIG.
An antenna apparatus according to Embodiment 8 of the present invention will be described with reference to FIG. FIG. 11 is a diagram showing a configuration of an antenna apparatus according to Embodiment 8 of the present invention. In the figure, (a) represents the front surface and (b) represents the back surface.

  In the eighth embodiment, the variable reactance element 25 is a variable capacitance diode.

  In FIG. 11, the antenna device according to the eighth embodiment includes a microstrip line strip conductor 16, a conductor 3 having a length of about a quarter wavelength, and a land conductor 29 on the surface of a dielectric substrate 15. A land conductor 30, a land conductor 31, a through hole 20, a high-frequency component blocking resistor (resistor) 22, a variable capacitance diode 25 connecting the land conductor 30 and the land conductor 31, and a land conductor 29. A capacitance element 28 for connecting the land conductor 31 and a voltage control line (linear conductor) 32 of the variable capacitance diode 25 are formed.

  Also, on the back surface of the dielectric substrate 15, a microstrip line ground conductor 17, a sleeve conductor 26 formed parallel to the ground conductor 17, and a connection conductor connecting the microstrip line ground conductor 17 and the sleeve conductor 26. 11 and a through hole 20 are formed.

  The sleeve conductor 26 and the ground conductor 17 of the microstrip line constitute a coplanar stripline 27.

  The land conductor 29 is connected to the sleeve conductor 26 through the through hole 20. The land conductor 30 is connected to the ground conductor 17 of the microstrip line via the through hole 20. The land conductor 31 is connected to the land conductor 29 via the capacitance element 28 and is connected to the land conductor 30 via the variable capacitance diode 25. The capacitance element 28 is installed between the land conductor 29 and the land conductor 31 so that no DC component flows but a high-frequency component flows. The capacitance of the capacitance element 28 is large enough to be regarded as being almost conductive when viewed in terms of high frequency components.

  The variable capacitance diode 25 is a diode whose capacitance value changes according to the applied reverse bias voltage. The reverse bias voltage is a DC voltage. Here, the reverse bias voltage is superimposed on the high frequency component of the microstrip line. Therefore, this antenna device has an advantage that it is not necessary to prepare a reverse bias voltage control line separately from the microstrip line. In order to apply a DC voltage superimposed on the microstrip line to the variable capacitance diode 25, a voltage control line 32 is provided. In order to prevent a high frequency component from flowing through the voltage control line 32, a large resistance 22 is provided between the voltage control line 32 and the strip conductor 16 of the microstrip line and between the voltage control line 32 and the land conductor 31. Has been inserted. The resistor 22 is sufficiently smaller than the DC resistance of the variable capacitance diode 25. Further, since the voltage control line 32 is on the back side of the connection conductor 11 and the sleeve conductor 26, it hardly affects the antenna characteristics of the present apparatus.

  The connection conductor 11, the sleeve conductor 26, the land conductor 29, the land conductor 30, the land conductor 31, the variable capacitance diode 25, the voltage control line 32, and the capacitance element 28 are provided one on each side of the microstrip line. The capacitances of the two variable capacitance diodes 25 are always set to the same value.

  Next, the operation of the antenna device according to the eighth embodiment will be described with reference to the drawings.

  In FIG. 11, the conductor 3 is fed by a microstrip line. At this time, the current flowing through the back surface side of the ground conductor 17 of the microstrip line (the side on which the ground conductor 17 is visible in FIG. 11B is referred to as the front surface side and the side that is not visible is referred to as the back surface side). 11, a part of the current leaks to the sleeve conductor 26.

  The sleeve conductor 26 constitutes a microstrip line ground conductor 17 and a coplanar strip line 27. Since there is one sleeve conductor 26 on each side of the ground conductor 17 of the microstrip line, there are two coplanar striplines 27 in this antenna device. If the reverse bias voltages of the two variable capacitance diodes 25 are simultaneously adjusted to an appropriate value and the capacitance value is adjusted, the impedance of the coplanar stripline 27 viewed from AA ′ in FIG. Leakage current flowing on the surface side of the ground conductor 17 of the microstrip line can be prevented below AA ′ in FIG.

  As described above, by simultaneously adjusting the reverse bias voltages of the two variable capacitance diodes 25, the leakage current flowing on the surface side of the ground conductor 17 of the microstrip line below AA ′ in FIG. 11 is prevented. Can do. Further, by changing the capacitances of the two variable capacitance diodes 25 at the same time, it is possible to change the frequency band for preventing the leakage current of the sleeve antenna.

  In addition, when the capacitance of the variable capacitance element 25 is reduced, the frequency for blocking the current is increased, but at the same time, the resonance frequency of the antenna is also increased. On the contrary, when the capacitance of the variable capacitance element 25 is increased, the frequency for blocking the current is lowered, but at the same time, the resonance frequency of the antenna is also lowered. Therefore, by appropriately changing the capacitance of the variable capacitance element 25 in accordance with the frequency to be used, it is possible to prevent leakage current and always maintain a resonance state at the frequency at which the antenna input impedance is used. As described above, the operation of blocking the leakage current and the input impedance of the antenna apparatus are linked, and there is an advantage that the blocking of the leakage current and the impedance matching can be realized at the same time even if the frequency used is changed.

  Further, when the length of the sleeve conductor 26 is close to a quarter wavelength, the current flowing through the conductor 3 and the current flowing through the sleeve conductor 26 produce the same current distribution as that of the half-wave dipole antenna, and the radiation pattern of this antenna apparatus Is the same as the radiation pattern of a half-wave dipole antenna.

  The resistor 22 may be an inductor. The through hole 20 may be a short pin.

  As described above, in the eighth embodiment, when the variable reactance element 25 is a variable capacitance diode, an example of the reverse bias voltage control method for the variable capacitance diode is shown. That is, if this antenna apparatus is used, since the reverse bias voltage is superimposed on the microstrip line, there is no need to prepare a separate reverse bias voltage control line, and the configuration is simplified. Also, the reverse bias voltage value of the variable capacitance diode 25 inserted between the sleeve conductor 26 and the ground conductor 17 of the microstrip line is changed to change the frequency band for preventing the leakage current, and at the same time, the antenna is interlocked. By changing the resonance frequency of the sleeve antenna device, it is possible to realize a sleeve antenna device having good reflection characteristics in a desired frequency band. If this sleeve antenna device is used, the frequency band for preventing leakage current can be changed by adjusting the reverse bias voltage of the variable capacitance diode 25 without increasing the distance between the sleeve conductor 26 and the ground conductor 17 of the microstrip line. By doing so, the sleeve antenna can be operated over a wide frequency band. That is, there is an effect that it is possible to obtain a sleeve antenna device that operates over a wide frequency band, is small and light, and has good reflection characteristics in a desired frequency band.

Embodiment 9 FIG.
In the ninth embodiment, the effect when the dielectric substrate 15 of the antenna device according to the fourth embodiment is covered with two cylindrical sleeve conductors will be clarified. FIG. 12 is a perspective view showing the configuration of the antenna apparatus according to Embodiment 9 of the present invention. In the figure, (a) represents the front surface and (b) represents the back surface.

  12, in the antenna device according to the ninth embodiment, the cylindrical sleeve conductor 33 and the cylindrical sleeve conductor 34 cover the dielectric substrate 15. Here, the cylindrical sleeve conductor 33 has the same length as the two sleeve conductors 12 on both sides of the ground conductor 17, covers the two sleeve conductors 12, and is electrically connected to the sleeve conductor 12. The cylindrical sleeve conductor 34 has the same length as the two sleeve conductors 13 on both sides of the strip conductor 16, covers the two sleeve conductors 13, and is electrically connected to the sleeve conductor 13. The two sleeve conductors 12 on both sides of the ground conductor 17 have the same length, and the two sleeve conductors 13 on both sides of the strip conductor 16 have the same length.

  Further, the sleeve conductor 12 and the sleeve conductor 13 are elongated strip-shaped conductors, and are installed along the end sides of the dielectric substrate 15.

  Here, the cylindrical sleeve antenna shown in FIG. 1 is compared with the plate-like sleeve antenna shown in FIG. If the diameter of the cylindrical sleeve antenna is the same as the width of the plate sleeve antenna, the cylindrical sleeve antenna has a wider frequency band for preventing leakage current flowing in the feeder line. Therefore, the cylindrical sleeve antenna can be downsized compared to the plate-shaped sleeve antenna. However, in general, a cylindrical sleeve antenna has a problem that it is difficult to make compared with a plate sleeve antenna.

  The antenna device according to the ninth embodiment is made to solve these problems. The sleeve conductor 12 and the sleeve conductor 13 of the antenna formed on the dielectric substrate 15 are respectively provided with cylindrical sleeve conductors. By connecting the 33 and the cylindrical sleeve conductor 34 to each other, the manufacturing method is simple, and a small and wide-band sleeve antenna can be obtained. The ninth embodiment can also be applied to the case where the sleeve conductors 13 and 12 are provided only on one side of the strip conductor 16 and the ground conductor 17 in the fourth embodiment.

Embodiment 10 FIG.
In the tenth embodiment, the effect when the dielectric substrate 15 of the antenna device according to the eighth embodiment is covered with a cylindrical sleeve conductor will be clarified. FIG. 13 is a perspective view showing the configuration of the antenna apparatus according to Embodiment 10 of the present invention. In the figure, (a) represents the front surface and (b) represents the back surface.

In the antenna device according to the tenth embodiment, the cylindrical sleeve conductor 35 covers the dielectric substrate 15 in FIG. Here, the cylindrical sleeve conductor 35 has the same length as the two sleeve conductors 26 on both sides of the ground conductor 17, covers the two sleeve conductors 26, and is electrically connected to the sleeve conductor 26. The two sleeve conductors 26 on both sides of the ground conductor 17 have the same length.

  The sleeve conductor 26 is an elongated strip-shaped conductor, and is installed along the end side of the dielectric substrate 15.

  Here, the cylindrical sleeve antenna shown in FIG. 8 and the plate-like sleeve antenna shown in FIG. 11 are compared. If the diameter of the cylindrical sleeve antenna is the same as the width of the plate sleeve antenna, the cylindrical sleeve antenna has a wider frequency band for preventing leakage current flowing in the feeder line. Therefore, the cylindrical sleeve antenna can be downsized compared to the plate-shaped sleeve antenna. However, in general, a cylindrical sleeve antenna has a problem that it is difficult to make compared with a plate sleeve antenna.

  The antenna device according to the tenth embodiment is made to solve these problems. The antenna sleeve conductor 26 formed on the dielectric substrate 15 is covered with a cylindrical sleeve conductor 35 to conduct. By doing so, it is possible to obtain a sleeve antenna having a simple and small and wide band. The tenth embodiment can also be applied to the case where the sleeve conductor 26 is provided only on one side of the ground conductor 17 in the eighth embodiment.

  In addition, in said Embodiment 1-10, the shape of the conductor 3 which contributes to radiation | emission is not limited in this application. Any shape such as a linear shape, a cylinder, a rectangle, or a triangle is assumed.

  In the second embodiment, the first sleeve conductor 12, the second sleeve conductor 13, the connection conductor 11, and the variable reactance element 7 are provided one on each side of the ground conductor 10. You may install only one on one side.

  In the third embodiment, the first sleeve conductor 12, the second sleeve conductor 13, the connection conductor 11, and the variable reactance element 7 are installed one on each side of the ground conductor 17 of the microstrip line. Only one microstrip line ground conductor 17 may be provided on one side.

  In the fourth embodiment, the first sleeve conductor 12, the second sleeve conductor 13, the connection conductor 11, the variable capacitance diode 7, the land conductor 19, the through hole 20, and the voltage control line 21 are microstrip lines. Although one is installed on each side of the ground conductor 17, only one may be installed on one side of the ground conductor 17 of the microstrip line.

  In the sixth embodiment, the sleeve conductor 26, the connection conductor 11, and the variable reactance element 25 are installed one on each side of the ground conductor 10, but only one may be installed on one side of the ground conductor 10. good.

  In the seventh embodiment, the sleeve conductor 26, the connection conductor 11, and the variable reactance element 25 are provided on both sides of the ground conductor 17 of the microstrip line, but one side of the ground conductor 17 of the microstrip line. You may install only one.

  Further, in the above-described eighth embodiment, the sleeve conductor 26, the connecting conductor 11, the variable capacitance diode 25, the land conductor 29, the land conductor 30, the land conductor 31, the voltage control line 32, and the capacitance element 28 are the microstrip line ground. Although one is installed on each side of the conductor 17, only one may be installed on one side of the ground conductor 17 of the microstrip line.

It is a perspective view which shows the structure of the antenna device which concerns on Embodiment 1 of this invention. It is a perspective view which shows the structure of the antenna apparatus which concerns on Embodiment 2 of this invention. It is a figure which shows the leakage current-frequency characteristic of the antenna device which concerns on Embodiment 2 of this invention. It is a Smith chart which shows the measurement result of the input impedance of the antenna device which concerns on Embodiment 2 of this invention. It is a Smith chart which expanded a part of FIG. It is a figure which shows the structure of the antenna apparatus which concerns on Embodiment 3 of this invention. It is a figure which shows the structure of the antenna device which concerns on Embodiment 4 of this invention. It is a perspective view which shows the structure of the antenna apparatus which concerns on Embodiment 5 of this invention. It is a perspective view which shows the structure of the antenna device which concerns on Embodiment 6 of this invention. It is a figure which shows the structure of the antenna device which concerns on Embodiment 7 of this invention. It is a figure which shows the structure of the antenna apparatus which concerns on Embodiment 8 of this invention. It is a figure which shows the structure of the antenna apparatus which concerns on Embodiment 9 of this invention. It is a figure which shows the structure of the antenna apparatus which concerns on Embodiment 10 of this invention.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 Coaxial line, 2 Outer conductor, 3 Conductor, 5 Connection conductor, 6 Sleeve conductor, 7 Variable reactance element, 8 Sleeve conductor, 9 Coaxial line, 10 Ground conductor, 11 Connection conductor, 12 Sleeve conductor, 13 Sleeve conductor, 14 Coplanar Strip line, 15 Dielectric substrate, 16 Strip conductor, 17 Ground conductor, 18 Coplanar strip line, 19 Land conductor, 20 Through hole, 21 Voltage control line, 22 Resistance, 23 Sleeve conductor, 24 Coaxial line, 25 Variable reactance Element, 26 Sleeve conductor, 27 Coplanar stripline, 28 Capacitance element, 29 Land conductor, 30 Land conductor, 31 Land conductor, 32 Voltage control line, 33 Cylindrical sleeve conductor, 34 Cylindrical sleeve conductor, 35 Cylindrical sleeve conductor .

Claims (28)

A coaxial line composed of an inner conductor and an outer conductor;
A radiation conductor connected to the inner conductor at the end of the coaxial line;
First and second sleeve conductors covering the outer conductor of the coaxial line;
A connection conductor connecting the outer conductor and the first sleeve conductor at the end of the coaxial line;
An antenna device comprising: a variable reactance element that connects the first and second sleeve conductors. The radiation conductor is a linear conductor;
The first and second sleeve conductors are cylindrical conductors;
The antenna device according to claim 1, wherein the connection conductor is a bowl-shaped conductor, and the variable reactance element is a variable capacitance element. A coaxial line composed of an inner conductor and an outer conductor;
A radiation conductor connected to the inner conductor at the end of the coaxial line;
A ground conductor connected in parallel to the outer conductor of the coaxial line;
First and second sleeve conductors installed parallel to the ground conductor;
Third and fourth sleeve conductors installed parallel to the ground conductor and 180 degrees opposite to the first and second sleeve conductors;
A connection conductor connecting the ground conductor and the first and third sleeve conductors at the end of the coaxial line;
A first variable reactance element connecting the first and second sleeve conductors;
An antenna device comprising: a second variable reactance element that connects the third and fourth sleeve conductors. The radiation conductor is a linear conductor;
The ground conductor is an elongated conductor;
The antenna device according to claim 3, wherein the first, second, third, and fourth sleeve conductors are strip-shaped conductors, and the first and second variable reactance elements are variable capacitance elements. A microstrip line composed of a strip conductor and a ground conductor;
A radiation conductor connected to the strip conductor at the tip of the microstrip line;
First, second, third and fourth sleeve conductors installed parallel to the microstrip line;
A connection conductor connecting the ground conductor and the first and third sleeve conductors at the tip of the microstrip line;
A first variable reactance element connecting the first and second sleeve conductors;
An antenna device comprising: a second variable reactance element that connects the third and fourth sleeve conductors. A strip conductor of the microstrip line is formed on the surface of the dielectric substrate;
A ground conductor of the microstrip line is formed on the back surface of the dielectric substrate;
The radiation conductor is a flat conductor,
The first and second sleeve conductors are strip-shaped conductors installed in parallel to the ground conductor;
The third and fourth sleeve conductors are strip-like conductors installed in parallel to the ground conductor and 180 degrees opposite to the first and second sleeve conductors, and the first and first The antenna device according to claim 5, wherein the two variable reactance elements are variable capacitance elements. A strip conductor of the microstrip line is formed on the surface of the dielectric substrate;
A ground conductor of the microstrip line is formed on the back surface of the dielectric substrate;
The radiation conductor is a flat conductor,
The first and third sleeve conductors are strip-shaped conductors installed in parallel on both sides of the ground conductor,
The second and fourth sleeve conductors are strip-shaped conductors installed in parallel on both sides of the strip conductor;
A first land conductor connected to the first sleeve conductor via a first through hole;
A second land conductor connected to the third sleeve conductor via a second through hole;
The first variable reactance element connects the first land conductor and the second sleeve conductor;
The antenna apparatus according to claim 5, wherein the second variable reactance element connects the second land conductor and the fourth sleeve conductor, and the first and second variable reactance elements are variable capacitance diodes. A first linear conductor formed on the back side of the first sleeve conductor and the connection conductor;
A second linear conductor formed on the back side of the third sleeve conductor and the connection conductor;
A first resistor, a second resistor, a third resistor, and a fourth resistor disposed on the surface of the dielectric substrate;
The first resistor connects the first linear conductor and the strip conductor;
The second resistor connects the first linear conductor and the second sleeve conductor;
The third resistor connects the second linear conductor and the strip conductor, and the fourth resistor connects the second linear conductor and the fourth sleeve conductor. The antenna device described. A coaxial line composed of an inner conductor and an outer conductor;
A radiation conductor connected to the inner conductor at the end of the coaxial line;
A sleeve conductor covering the outer conductor of the coaxial line;
A connection conductor connecting the outer conductor and the sleeve conductor at the tip of the coaxial line;
An antenna device comprising: a variable reactance element that connects the outer conductor and the sleeve conductor. The radiation conductor is a linear conductor;
The sleeve conductor is a cylindrical conductor;
The antenna device according to claim 9, wherein the connection conductor is a bowl-shaped conductor, and the variable reactance element is a variable capacitance element. A coaxial line composed of an inner conductor and an outer conductor;
A radiation conductor connected to the inner conductor at the end of the coaxial line;
A ground conductor connected in parallel to the outer conductor of the coaxial line;
A first sleeve conductor disposed parallel to the ground conductor;
A second sleeve conductor disposed parallel to the ground conductor and disposed 180 degrees opposite the first sleeve conductor;
A connection conductor connecting the ground conductor and the first and second sleeve conductors at the end of the coaxial line;
A first variable reactance element connecting the ground conductor and the first sleeve conductor;
An antenna device comprising: a second variable reactance element that connects the ground conductor and the second sleeve conductor. The radiation conductor is a linear conductor;
The ground conductor is an elongated conductor;
The antenna device according to claim 11, wherein the first and second sleeve conductors are strip-shaped conductors, and the first and second variable reactance elements are variable capacitance elements. A microstrip line composed of a strip conductor and a ground conductor;
A radiation conductor connected to the strip conductor at the tip of the microstrip line;
First and second sleeve conductors installed in parallel to the microstrip line;
A connection conductor connecting the ground conductor and the first and second sleeve conductors at the tip of the microstrip line;
A first variable reactance element connecting the ground conductor and the first sleeve conductor;
An antenna device comprising: a second variable reactance element that connects the ground conductor and the second sleeve conductor. A strip conductor of the microstrip line is formed on the surface of the dielectric substrate;
A ground conductor of the microstrip line is formed on the back surface of the dielectric substrate;
The radiation conductor is a flat conductor,
The first sleeve conductor is a strip-shaped conductor installed in parallel to the ground conductor;
The second sleeve conductor is a strip-shaped conductor disposed in parallel to the ground conductor and 180 degrees opposite to the first sleeve conductor, and the first and second variable reactance elements are The antenna device according to claim 13, wherein the antenna device is a variable capacitance element. A strip conductor of the microstrip line is formed on the surface of the dielectric substrate;
A ground conductor of the microstrip line is formed on the back surface of the dielectric substrate;
The radiation conductor is a flat conductor,
The first and second sleeve conductors are strip-shaped conductors installed in parallel on both sides of the ground conductor,
A first land conductor connected to the first sleeve conductor via a first through hole;
A second land conductor connected to the second sleeve conductor via a second through hole;
A third land conductor connected to the ground conductor through a third through hole;
A fourth land conductor connected to the ground conductor through a fourth through hole;
Fifth and sixth land conductors formed on the surface of the dielectric substrate;
A first linear conductor formed on the back side of the first sleeve conductor and the connection conductor;
A second linear conductor formed on the back side of the second sleeve conductor and the connection conductor;
First, second, third and fourth resistors installed on the surface of the dielectric substrate;
First and second capacitance elements installed on the surface of the dielectric substrate,
The first variable reactance element connects the third land conductor and the fifth land conductor;
The second variable reactance element connects the fourth land conductor and the sixth land conductor;
The first capacitance element connects the first land conductor and the fifth land conductor;
The second capacitance element connects the second land conductor and the sixth land conductor;
The first resistor connects the first linear conductor and the strip conductor;
The second resistor connects the first linear conductor and the fifth land conductor;
The third resistor connects the second linear conductor and the strip conductor;
The antenna device according to claim 13, wherein the fourth resistor connects the second linear conductor and the sixth land conductor, and the first and second variable reactance elements are variable capacitance diodes. A coaxial line composed of an inner conductor and an outer conductor;
A radiation conductor connected to the inner conductor at the end of the coaxial line;
A ground conductor connected in parallel to the outer conductor of the coaxial line;
First and second sleeve conductors installed parallel to the ground conductor;
A connection conductor connecting the ground conductor and the first sleeve conductor at the end of the coaxial line;
An antenna device comprising: a variable reactance element that connects the first and second sleeve conductors. The radiation conductor is a linear conductor;
The ground conductor is an elongated conductor;
The antenna device according to claim 16, wherein the first and second sleeve conductors are strip-shaped conductors, and the variable reactance element is a variable capacitance element. A microstrip line composed of a strip conductor and a ground conductor;
A radiation conductor connected to the strip conductor at the tip of the microstrip line;
First and second sleeve conductors installed in parallel to the microstrip line;
A connection conductor connecting the ground conductor and the first sleeve conductor at the tip of the microstrip line;
An antenna device comprising: a variable reactance element that connects the first and second sleeve conductors. A strip conductor of the microstrip line is formed on the surface of the dielectric substrate;
A ground conductor of the microstrip line is formed on the back surface of the dielectric substrate;
The radiation conductor is a flat conductor,
The antenna device according to claim 18, wherein the first and second sleeve conductors are strip-like conductors installed in parallel to the ground conductor, and the variable reactance element is a variable capacitance element. A strip conductor of the microstrip line is formed on the surface of the dielectric substrate;
A ground conductor of the microstrip line is formed on the back surface of the dielectric substrate;
The radiation conductor is a flat conductor,
The first sleeve conductor is a strip-shaped conductor installed in parallel to the ground conductor;
The second sleeve conductor is a strip-shaped conductor disposed parallel to the strip conductor;
A land conductor connected to the first sleeve conductor through a through hole;
The antenna device according to claim 18, wherein the variable reactance element connects the land conductor and the second sleeve conductor, and the variable reactance element is a variable capacitance diode. A coaxial line composed of an inner conductor and an outer conductor;
A radiation conductor connected to the inner conductor at the end of the coaxial line;
A ground conductor connected in parallel to the outer conductor of the coaxial line;
A sleeve conductor installed parallel to the ground conductor;
A connection conductor connecting the ground conductor and the sleeve conductor at a tip of the coaxial line;
An antenna device comprising: a variable reactance element that connects the ground conductor and the sleeve conductor. The radiation conductor is a linear conductor;
The ground conductor is an elongated conductor;
The antenna device according to claim 21, wherein the sleeve conductor is a strip-shaped conductor, and the variable reactance element is a variable capacitance element. A microstrip line composed of a strip conductor and a ground conductor;
A radiation conductor connected to the strip conductor at the tip of the microstrip line;
A sleeve conductor installed in parallel to the microstrip line;
A connection conductor connecting the ground conductor and the sleeve conductor at the tip of the microstrip line;
An antenna device comprising: a variable reactance element that connects the ground conductor and the sleeve conductor. A strip conductor of the microstrip line is formed on the surface of the dielectric substrate;
A ground conductor of the microstrip line is formed on the back surface of the dielectric substrate;
The radiation conductor is a flat conductor,
The antenna device according to claim 23, wherein the sleeve conductor is a strip-like conductor installed in parallel to the ground conductor, and the variable reactance element is a variable capacitance element. A strip conductor of the microstrip line is formed on the surface of the dielectric substrate;
A ground conductor of the microstrip line is formed on the back surface of the dielectric substrate;
The radiation conductor is a flat conductor,
The sleeve conductor is a strip-shaped conductor installed in parallel to the ground conductor,
A first land conductor connected to the sleeve conductor via a first through hole;
A second land conductor connected to the ground conductor through a second through hole;
A third land conductor formed on the surface of the dielectric substrate;
A linear conductor formed on the back side of the sleeve conductor and the connection conductor;
First and second resistors installed on the surface of the dielectric substrate;
A capacitance element installed on the surface of the dielectric substrate,
The variable reactance element connects the second land conductor and the third land conductor;
The capacitance element connects the first land conductor and the third land conductor;
The first resistor connects the linear conductor and the strip conductor;
The antenna device according to claim 23, wherein the second resistor connects the linear conductor and the third land conductor, and the variable reactance element is a variable capacitance diode. Further comprising first and second cylindrical sleeve conductors covering the dielectric substrate;
The first cylindrical sleeve conductor is the same length as the first sleeve conductor, covers the first sleeve conductor, and is electrically connected to the first sleeve conductor;
The second cylindrical sleeve conductor has the same length as the second sleeve conductor, covers the second sleeve conductor, and is electrically connected to the second sleeve conductor. 20. The antenna device according to 20. A cylindrical sleeve conductor covering the dielectric substrate;
The lengths of the first and second sleeve conductors are the same;
The cylindrical sleeve conductor has the same length as the first or second sleeve conductor, covers the first and second sleeve conductors, and is electrically connected to the first or second sleeve conductor. The antenna device according to claim 15. A cylindrical sleeve conductor covering the dielectric substrate;
The antenna device according to claim 25, wherein the cylindrical sleeve conductor has the same length as the sleeve conductor, covers the sleeve conductor, and is electrically connected to the sleeve conductor.

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