JP2001244731A - Antenna system and array antenna using the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To solve the problems of a conventional antenna system that has had an asymmetrical radiation pattern and increased cross-polarized radiation waves, because of the influence of a radiation mode from a feeder line. SOLUTION: The antenna system is provided with a ground conductor, a 1st linear antenna placed above the ground conductor apart at most by about an eight of wavelength, a feeder line that feeds power to the 1st linear antenna and is exposed above the ground conductor by the length of the 1st linear antenna, and a parasitic 2nd linear antenna that has nearly the same resonance frequency as that of the 1st linear antenna is placed at a position apart from the upper ground conductor by about quarter of wavelength, so as to be nearly in parallel with the 1st linear antenna and excited through an electromagnetic field action from the 1st linear antenna.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an antenna device having a small cross-polarization and having a symmetric radiation pattern and a wide band characteristic, and an array antenna using the same.

[0002]

2. Description of the Related Art Diversity reception is employed in a base station antenna for mobile communication in order to improve communication quality. Such diversity branch configuration methods include:
Although space diversity is often used, two antennas must be installed at a certain distance or more apart from each other, and there is a disadvantage that the antenna installation space is large. In addition, as a diversity branch with a small installation space,
Polarization diversity using multiple propagation characteristics between different polarizations is effective, and can be realized by configuring an antenna having a vertical polarization and an antenna having a horizontal polarization. Furthermore, by using both polarized waves in the radar antenna, polarimetry for identifying an object from a difference in radar cross-sectional area due to polarized waves can be realized.

[0003] In order to realize the above-mentioned polarization diversity or polarimetry, an antenna having excellent cross polarization characteristics is required. A dipole antenna is often used as such an antenna element. FIG. 8 is a perspective view showing a configuration of a conventional dipole antenna used for a base station antenna or the like. In the figure, 100 is a ground conductor on which a dielectric substrate 400 is erected, and 200 is a dielectric substrate 40
A dipole antenna formed on 0, 300 is a feed line for feeding the dipole antenna 200, and 400 is a dielectric substrate.

Next, the outline will be described. A dipole antenna has a relatively wide band characteristic, and a bandwidth of 10% or more can be obtained. To obtain this band, the height from the ground conductor to the dipole antenna is about 1 of the used wavelength.
以上 (１ ／ wavelength) or more. If the height from the ground conductor to the dipole antenna is reduced, the dipole antenna has a narrow band. Therefore, the distance from the ground conductor is important for obtaining a wide band characteristic.

In general, a parallel two-wire or coaxial line is used as a feed line for feeding a dipole antenna. When a dipole antenna is formed by using a printed circuit board as a dielectric substrate, there is an advantage in that such parallel two lines do not require soldering and can be easily manufactured. Further, the configuration of the feeder line up to two parallel lines is converted from a coaxial connector into a microstrip line, and the microstrip line is converted into two parallel lines via an unbalanced balanced conversion circuit (hereinafter, referred to as a balun). Then, the dipole antenna is excited from the two parallel wires.

[0006]

Since the conventional antenna device is configured as described above, the radiation pattern becomes asymmetric or the cross polarization increases due to the radiation mode from the feed line. was there.

More specifically, the normal mode is normally transmitted to the two parallel lines, but is converted from a microstrip line, which is an unbalanced line, to a two parallel line, which is a balanced line, via a balun. However, a common mode is generated by the balun. Such a balun has a limitation in an operating frequency band, and a limitation on the conversion performance of the balun. In particular, when a wider band or a smaller size is required, the balun cannot perform ideal excitation. That is,
A common mode occurs in which in-phase currents flow through the two parallel wires. Such a common mode current is not transmitted,
Since the mode is radiated, it is radiated from the feed line. Since this radiation mode has a radiation pattern similar to that of a monopole antenna, if it is superimposed on the radiation mode from a dipole antenna, the radiation pattern will be synthesized, resulting in an asymmetric radiation pattern. Cross polarization increases.

Further, in an array antenna in which a plurality of conventional antenna devices are arranged as antenna elements,
There has been a problem that the influence of the radiation mode due to the common mode current flowing through the feed line is further increased by the coupling between the elements, and the radiation characteristics are deteriorated.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-described problems, and has as its object to obtain an antenna device having a small cross polarization, a symmetric radiation pattern, and a wide band characteristic.

Another object of the present invention is to provide an array antenna in which the influence of a radiation mode from a feed line due to coupling between elements is reduced.

[0011]

An antenna device according to the present invention comprises a ground conductor, a first linear antenna provided at a distance of at most about 1/8 wavelength above the ground conductor, and the first linear antenna. And a feed line that is exposed above the ground conductor by the length up to the first linear antenna, and has a resonance frequency substantially the same as that of the first linear antenna, and is substantially parallel to the first linear antenna. And a non-powered second linear antenna that is provided at a position approximately one-quarter wavelength away from the ground conductor above it and that is excited by an electromagnetic field effect from the first linear antenna. is there.

The antenna device according to the present invention is shorter than the element length of the second linear antenna and is provided at a distance of about 1/4 wavelength from about 1/8 wavelength so as to be substantially parallel to the second linear antenna. , And at least one non-feeding third linear antenna that is excited by receiving an electromagnetic action from the second linear antenna.

The antenna device according to the present invention has a resonance frequency higher than that of the second linear antenna, and is provided near the pole above the second linear antenna so as to be substantially parallel to the second linear antenna. And at least one non-feeding fourth linear antenna which is excited by an electromagnetic field from the antenna.

An antenna device according to the present invention includes a ground conductor, a first linear antenna provided at a distance of at most about 1/8 wavelength above the ground conductor, and a power supply to the first linear antenna.
A feed line that is exposed above the ground conductor by a length up to the first linear antenna, has a resonance frequency that is substantially the same as that of the first linear antenna, and receives an electromagnetic field effect from the first linear antenna; A non-feeding linear antenna that excites the first linear antenna at a position approximately 1/4 wavelength away from the ground conductor above it so as to be substantially parallel to the first linear antenna. At least two fifth linear antennas are provided so as to be symmetrical.

In the antenna device according to the present invention, the non-feeding linear antenna is made thicker than the first linear antenna receiving the feeding.

The antenna device according to the present invention is obtained by bending a non-feeding linear antenna at both ends toward the ground conductor so as to be substantially symmetric with respect to the center.

In the antenna device according to the present invention, the linear antenna and the feed line are integrally formed on a dielectric substrate.

An array antenna according to the present invention is obtained by arranging a plurality of antenna devices according to any one of claims 1 to 7.

[0019]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will be described below. Embodiment 1 FIG. FIG. 1 is a perspective view showing the configuration of the antenna device according to Embodiment 1 of the present invention. In the figure, 1
Is a ground conductor, and 2 is a first dipole antenna (first linear antenna) provided above the ground conductor 1 at a distance of about 、 wavelength or less, and a first dipole antenna formed on the back surface of the dielectric substrate 4. Is shown by a broken line. Three
Is a feed line for feeding the first dipole antenna 2, and is exposed above the ground conductor 1 by a length up to the first dipole antenna 2. Reference numeral 4 denotes a dielectric substrate on which the first dipole antenna 2, the second dipole antenna 5, and the feed line 3 are integrally formed. Numeral 5 has a resonance frequency substantially the same as that of the first dipole antenna 2, and is provided above the ground conductor 1 at a distance of about ４ wavelength so as to be substantially parallel to the first dipole antenna 2. And a non-feeding second dipole antenna (second linear antenna) which is excited by receiving an electromagnetic field effect from the first dipole antenna 2.

Next, the outline will be described. In order to obtain a wideband characteristic with a dipole antenna, the distance from the ground conductor to the dipole antenna needs to be about １ ／ wavelength or more. For this reason, a feed line for feeding the dipole antenna, for example, two parallel wires, must be exposed on the ground conductor for at least about 1/4 wavelength. However,
The radiation amount of the common mode radiation of two parallel lines increases as the length increases. It is desirable that the feed line exposed on the ground conductor be as short as possible.

Therefore, in the antenna device of the present invention, by disposing the first dipole antenna 2 near the ground conductor 1 (at most about 1/8 wavelength), the feed line 3 exposed on the ground conductor 1 is formed. Shortening. However, simply shortening the feed line 3 exposed on the ground conductor 1 results in a narrow band characteristic. For this reason, in the antenna device according to the first embodiment, the resonance frequency of the first dipole antenna 2 that is fed with power and the resonance frequency of the second dipole antenna 5 that is not fed are almost the same, and A non-feeding second dipole antenna 5 is installed at a distance of about 1/4 wavelength from the ground conductor 1 above. By doing so, the first dipole antenna 2 and the second
The use of the electromagnetic coupling with the dipole antenna 5 of the first embodiment achieves a wider band. That is, by the electromagnetic field effect from the first dipole antenna 2 receiving the power,
The unpowered second dipole antenna 5 provided at a position approximately 1/4 wavelength above the ground conductor 1 is excited to be in a resonance state.
, The band characteristic of a wide band is exhibited as compared with the case where the antenna is provided at a position separated by approximately 1/4 wavelength above. FIG. 2 shows this quantitatively. In the following, a description will be given of the band broadening by the configuration of the present invention with reference to FIG.

FIG. 2 is a graph showing the return loss with respect to the normalized frequency in the antenna device according to the first embodiment, which is the simplest configuration of the present invention, and other configurations. In order to confirm the principle, a return loss characteristic with respect to whether or not a passive dipole antenna (second dipole antenna 5) is provided is shown. In the figure, the curve represented by the black square plot is the characteristic of the case where the dipole antenna receiving power is arranged at a position about 1/4 wavelength above the ground conductor (conventional antenna device), The curve represented by the circle symbol plots the characteristics when a dipole antenna that receives power is placed at a position approximately 1/8 wavelength above the ground conductor, and the curve represented by the black triangle symbol plots the ground conductor A non-feeding dipole antenna is placed at a position about 1/4 wavelength away from the ground, and about 1
This is a characteristic of the antenna device according to the first embodiment in which a dipole antenna receiving power supply is arranged at a position / 8 wavelength away. Here, the return loss is equivalent to the amount of radiation when the radiation is reflected at the feeding point without being radiated from the antenna device. The greater the return loss (absolute value), the greater the radiation amount of the antenna device. .

As shown in FIG. 2, the curve represented by the black circle symbol plot in which the parasitic dipole antenna is not provided and the fed dipole antenna is separated from the ground conductor 1 by only about ８ wavelength is shown. It can be seen that the value of the return loss at the reference frequency becomes small, and the radiation efficiency is lowered without resonance. The curve of the conventional antenna device represented by the black square plot shows a large return loss at the reference frequency, whereas the curve of the antenna device according to the first embodiment represented by the black triangle plot is Exhibits a high return loss not only at the reference frequency but also at a frequency around the reference frequency, and the second dipole antenna 5 is provided at a position about 1/4 wavelength above the ground conductor 1 as a non-feeding dipole antenna. Thus, it can be seen that the bandwidth has been significantly increased.

As a conventional dipole antenna which obtains a high gain by disposing a non-feeding dipole antenna near the dipole antenna as described above, there is a Yagi antenna. This Yagi antenna is described in, for example, Uchida and Mushiaki, "Ultra High Frequency Antenna", Production Technology Center.As the configuration, it is possible to use a powered dipole antenna without approaching a ground conductor, etc. By appropriately setting the distance from the ground conductor, the antenna can be operated as a wideband dipole antenna. Furthermore, about 1/4 from the dipole antenna receiving the above power supply
A non-feeding dipole antenna is arranged at a distance from the wavelength, and the element length is made shorter than that of the dipole antenna receiving the feeding, thereby delaying the phase of the non-feeding dipole antenna. By doing so, the radiation field of the dipole antenna that receives power in the direction of the unpowered dipole antenna is in phase and has directivity. Thus, the non-feeding dipole antenna in the Yagi antenna is used as a component for providing directivity. On the other hand, although the antenna device of the present invention cannot normally be brought into a resonance state when the distance between the ground conductor and the feed dipole antenna is about 1/4 wavelength or less as described above,
In order to reduce the influence of radiation from the feed line, a feed dipole antenna is arranged at a position at most about 1/8 wavelength away, and a parasitic dipole antenna provided at a position about 1/4 wavelength away from the ground conductor A resonance state is obtained by utilizing the electromagnetic coupling between the Yagi antenna and the Yagi antenna, and such a wide band cannot be achieved with the configuration of the Yagi antenna as described above.

As described above, according to the first embodiment, the ground conductor 1, the first dipole antenna 2 provided above the ground conductor 1 and separated by at most about ８ wavelength, And a power supply line 3 that supplies power to the first dipole antenna 2 and that is exposed above the ground conductor 1 by a length up to the first dipole antenna 2, and has a resonance frequency substantially the same as that of the first dipole antenna 2. The first dipole antenna 2 is provided so as to be substantially parallel to the first dipole antenna 2 and separated from the ground conductor 1 by approximately 1/4 wavelength.
And a non-feeding second dipole antenna 5 that receives and excites the electromagnetic field from the antenna, thereby obtaining a broadband characteristic even if the length of the feed line 3 for feeding the first dipole antenna 2 is shortened. Therefore, the amount of radiation from the feed line 3 can be reduced. Thereby, a radiation pattern with good symmetry can be obtained, and cross polarization can be reduced.

Although the first embodiment shows an example in which the first dipole antenna 2 is fed above the ground conductor 1 at a distance of about 1/8 wavelength, the same characteristics can be obtained even when the power is about 1/20 wavelength. Has been confirmed by experiments. In short, the first dipole antenna 2 may be provided as close to the ground conductor 1 as possible, and by adjusting the position of the second dipole antenna 5, a wider band can be achieved.

Embodiment 2 FIG. In the second embodiment, a non-feeding linear antenna disposed above a linear antenna to be fed with power is thickened to improve wideband characteristics.

FIG. 3 is a perspective view showing the configuration of the antenna device according to the second embodiment of the present invention. In the figure, 5a
Is a non-powered second dipole antenna (second
The first dipole antenna 2 is configured to have a thicker end than the radiating element of the first dipole antenna 2. The same components as those in FIG. 1 are denoted by the same reference numerals, and duplicate description will be omitted.

Next, the outline will be described. As in the first embodiment, the second dipole antenna 5a is arranged above the first dipole antenna 2 at a distance of about 1/4 wavelength from the ground conductor 1 in order to obtain a wideband characteristic. At this time, it has been experimentally found that a wider band can be achieved by making the non-feeding dipole antenna thicker (in the case of a dipole antenna printed on a dielectric substrate, the element width is increased). Therefore, the second embodiment
In this example, the band is widened by making the second dipole antenna 5a thick. In particular, FIG. 3 shows an example in which the element end of the second dipole antenna 5a is made thicker to form a bow-tie antenna. By doing so, the bandwidth is improved as compared with a case where the element is simply made thicker. be able to.

As described above, according to the second embodiment, the second dipole antenna 5a, which is not fed with power, is made thicker than the first dipole antenna 2 which receives power, so that the same effects as those of the first embodiment are obtained. And the broadband characteristics can be further improved.

In the above-described second embodiment, an example is shown in which the configuration for increasing the width of the parasitic dipole antenna is applied to the first embodiment. However, the present invention is not limited to this and is applicable to the configuration described in the following embodiment. Is also good.

Embodiment 3 FIG. In the third embodiment, the both ends of the unpowered linear antenna are bent toward the ground conductor so as to be substantially symmetrical with respect to the center thereof, so that the difference in beam width due to the cut surface is reduced. This is to reduce the occurrence.

FIG. 4 is a perspective view showing a configuration of an antenna device according to Embodiment 3 of the present invention. In the figure, 5b
Is a second dipole antenna (second linear antenna) whose both ends are bent toward the ground conductor 1 so as to be substantially symmetric with respect to the center. The same components as those in FIG. 1 are denoted by the same reference numerals, and duplicate description will be omitted.

Next, the outline will be described. The radiation pattern of the dipole antenna varies depending on the cut plane. The E plane shows a figure-shaped directivity, and the H plane shows omnidirectionality. That is,
The beam width of the E plane, which is a plane containing the electric field vector, is narrow, and the beam width of the H plane, which is a plane containing the magnetic field vector, is wide. The difference in beam width due to such a cut surface poses a problem in applications where communication is performed in all directions because the gain may be different depending on the communication direction. In order to reduce the difference in directivity due to the cut surface, if it is required to make the radiation pattern of the dipole antenna broader, it is necessary to increase the beam width on the E surface. Therefore, in the third embodiment, the second
Both ends are bent toward the ground conductor 1 so as to be substantially symmetrical with respect to the center of the dipole antenna 5b. By doing so, it becomes directional even in the wide-angle direction, and broad characteristics can be obtained. Further, the beam width of the E-plane can be adjusted by changing the bending angle.

As described above, according to the third embodiment, both ends are bent toward the ground conductor 1 so as to be substantially symmetric with respect to the center of the second dipole antenna 5b. While having the same effect as 1,
Since the beam width on the E-plane can be increased, it is possible to suppress the occurrence of a gain difference depending on the communication direction.
In addition, since the beam width can be adjusted by changing the angle of the inclination, the beam width can be used as a parameter for optimizing the antenna device so as to meet its intended use.

In the third embodiment, an example is shown in which the configuration in which the parasitic dipole antenna is bent is applied to the first embodiment. However, the present invention is not limited to this, and may be applied to the configuration of another embodiment. .

Embodiment 4 FIG. In the fourth embodiment, the directivity is improved by arranging a non-feeding linear antenna above the feeding linear antenna and further arranging a non-feeding linear antenna that operates as a director above the feeding linear antenna. It was made.

FIG. 5 is a perspective view showing a configuration of an antenna device according to Embodiment 4 of the present invention. In the figure, reference numeral 6 denotes a third dipole antenna (third linear antenna) disposed above the second dipole antenna 5. The same components as those in FIG. 1 are denoted by the same reference numerals, and duplicate description will be omitted.

Next, the outline will be described. In the example of FIG. 5, approximately 1
The second dipole antenna 5 is arranged at a position of 波長 wavelength, and a third dipole antenna 6 shorter than the element length of the second dipole antenna 5 is arranged above the second dipole antenna 5 at a distance of about ８ wavelength. In this way, the second dipole antenna 5 is excited by the electromagnetic action from the first dipole antenna 2, and the third dipole is excited by the electromagnetic action from the second dipole antenna 5. The antenna 6 is excited. As a result, similarly to the first embodiment, the feed line 3 that feeds the first dipole antenna 2
, The band characteristics can be widened, and the radio wave radiated from the antenna device according to the fourth embodiment has a directivity that is enhanced in the direction of the third dipole antenna 6. Become.

In order to operate the third dipole antenna 6 as a director as described above, the distance from the third dipole antenna 6 to the second dipole antenna 5 should be approximately ８ wavelength to approximately １ ／ wavelength. It is arranged at a position of about the wavelength, and its element length is shorter than that of the second dipole antenna 5. As a result, the phase of the third dipole antenna 6 is delayed from that of the second dipole antenna 5, and the phase of the radiation field of the second dipole antenna 5 in the direction of the third dipole antenna 6 matches, so that the radio wave is transmitted. Be able to be strengthened. Therefore, the antenna device according to the fourth embodiment has the same directivity as the Yagi antenna, and the gain in the communication direction can be increased.

As described above, according to the fourth embodiment, the element length of the second dipole antenna 5 is shorter than the element length of the second dipole antenna 5 and is substantially parallel to the second dipole antenna 5 from approximately 1/8 wavelength. A third dipole antenna 6, which is provided at a distance of 1/4 wavelength and is non-feeding, which is excited by an electromagnetic field from the second dipole antenna 5 and is excited by at least one
Since the third dipole antenna 6 operates as a director, directivity can be provided, and the gain in the communication direction can be improved. it can.

In the fourth embodiment, an example in which one third dipole antenna 6 is provided has been described. However, the present invention is not limited to this, and the distance from the third dipole antenna 6 is set to approximately 1 /.
A plurality of non-feeding dipole antennas operating as a director may be arranged at a distance of about 1/4 wavelength from 8 wavelengths.

Embodiment 5 FIG. In the fifth embodiment, a non-feeding linear antenna is arranged above a feeding linear antenna, and a parasitic antenna having a higher resonance frequency than the above-mentioned non-feeding linear antenna in the vicinity of an upper portion thereof. Are provided to provide two resonance characteristics.

FIG. 6 is a perspective view showing the structure of the antenna device according to the fifth embodiment of the present invention. In the figure, reference numeral 7 denotes a second dipole antenna which is disposed in the vicinity of
A fourth dipole antenna (fourth linear antenna) having a higher resonance frequency than the dipole antenna 5 of FIG. The same components as those in FIG. 1 are denoted by the same reference numerals, and duplicate description will be omitted.

Next, the outline will be described. In the antenna device according to the fifth embodiment, the second dipole antenna 5 and the fourth dipole antenna 7 are excited by the electromagnetic action from the first dipole antenna 2 and the feed line 3 is shortened. The ability to suppress banding is the same as in the first embodiment. Here, particularly, a configuration in which the second resonance characteristic can be obtained by providing the fourth dipole antenna 7 is shown. More specifically, in order for the third dipole antenna to operate as a director as described in the fourth embodiment, it is necessary to be separated from the second dipole antenna 5 by about 1/8 to 1/4 wavelength. However, in the fifth embodiment, the fourth dipole antenna 7 is placed close to the upper part of the second dipole antenna 5 (about 1
(Approximately / 10 to 1/20 wavelength) and are electromagnetically coupled. Thereby, the fourth dipole antenna 7 does not operate as a director, but matching can be achieved not only at the resonance frequency of the first dipole antenna 2 but also at the resonance frequency of the fourth dipole antenna 7. Characteristics can be obtained.

Further, in the fifth embodiment, the configuration in which two resonance characteristics are obtained by arranging one fourth dipole antenna 7 near the second dipole antenna 5 has been described.
Needless to say, a configuration in which a non-feeding dipole antenna is disposed above the fourth dipole antenna 7 to obtain resonance characteristics at three or more frequencies is also included in the scope of the present invention.

As described above, according to the fifth embodiment, a dipole antenna having a resonance frequency higher than that of the second dipole antenna 5 is provided so as to be substantially parallel to the second dipole antenna 5. At least one is provided in the vicinity of the upper pole, and is a non-powered fourth terminal that is excited by receiving an electromagnetic field effect from the second dipole antenna 5.
, Resonance characteristics at a plurality of frequencies can be obtained, and an optimal antenna device can be designed according to the intended use of the antenna device.

Embodiment 6 FIG. In the sixth embodiment, the antenna is provided at a position approximately 1/4 wavelength away from the ground conductor above the antenna so as to be substantially parallel to the linear antenna receiving power supply, and is substantially symmetric with respect to the linear antenna. At least 2
The difference in beam width due to the difference in cut plane is reduced by arranging two passive antennas.

FIG. 7 is a perspective view showing a configuration of an antenna device according to Embodiment 6 of the present invention. In the figure, 4a
Is a dielectric substrate on which the fifth dipole antennas 8 and 8 are integrally formed, and 8 is a position approximately 1/4 wavelength away from the ground conductor 1 above it so as to be substantially parallel to the first dipole antenna 2. And a non-feeding fifth dipole antenna (fifth linear antenna) arranged so as to be substantially symmetrical with respect to the first dipole antenna 2. FIG.
The same components as those described above are denoted by the same reference numerals, and redundant description will be omitted.

Next, the outline will be described. In the antenna device according to the sixth embodiment, the two fifth dipole antennas 8 and 8 are excited by the electromagnetic action from the first dipole antenna 2 to reduce the band width by shortening the feed line 3. This can be suppressed as in the first embodiment. Here, particularly, a configuration in which the beam width on the H plane is sharpened is shown. In other words, the fifth dipole antennas 8 and 8 are substantially parallel to the first dipole antenna 2 and at a position approximately 1/4 wavelength away from the ground conductor 1 above the first dipole antenna 2 with respect to the first dipole antenna 2. By disposing them symmetrically, the fifth dipole antennas 8 are arranged in the H-plane direction of the first dipole antenna 2. It has been experimentally found that such a configuration can reduce the beam width in the E-plane direction. At this time, the fifth dipole antennas 8, 8
Can be adjusted until the beam width on the H plane becomes substantially the same as the beam width on the E plane.

In the above description, an example in which the fifth dipole antennas 8 and 8 are arranged on the dielectric substrate 4a has been described. However, a non-feeding dipole antenna may be arranged with a spacer or the like interposed therebetween. The present invention is effective even if is changed.

As described above, according to the sixth embodiment, the ground conductor 1, the first dipole antenna 2 provided above the ground conductor 1 and separated by at most about １ ／ wavelength, And a power supply line 3 that supplies power to the first dipole antenna 2 and that is exposed above the ground conductor 1 by a length up to the first dipole antenna 2, and has a resonance frequency substantially the same as that of the first dipole antenna 2. This is a non-feeding linear antenna which is excited by receiving an electromagnetic field effect from the first dipole antenna 2 and is approximately 1/1/1 from the ground conductor 1 above the first dipole antenna 2 so as to be substantially parallel to the first dipole antenna 2. The fifth embodiment has at least two fifth dipole antennas 8 and 8 which are provided at positions separated by four wavelengths and are substantially symmetric with respect to the first dipole antenna 2.
Similarly to the case described above, even if the length of the feed line 3 for feeding the first dipole antenna 2 is shortened, broadband characteristics can be obtained, so that the amount of radiation from the feed line 3 can be reduced.
Thereby, a radiation pattern with good symmetry can be obtained, and cross polarization can be reduced.

Further, by arranging the fifth dipole antennas 8 and 8 which are not fed in the direction of the H plane, the beam width of the H plane can be narrowed, and the gain in the communication direction can be improved. Further, a fifth dipole antenna 8,
By adjusting the interval of 8, a beam width substantially equal to the E-plane beam width can be obtained, and the occurrence of a gain difference depending on the communication direction can be suppressed.

As described in the first to sixth embodiments, the components of the antenna device (the dipole antenna 2,
By forming the 5, 5a, 5b, 6, 7, 8 and the feed line 3) integrally with the dielectric substrate 4, it is possible to omit the step of connecting each component, thereby reducing the mass productivity of the device. Can be improved. Accordingly, mass productivity of an array antenna formed using the antenna devices described in Embodiments 1 to 6 can be improved.

In addition to the above, even if the antenna device of the present invention is constituted by a dipole antenna using a metal rod and a coaxial line, the same characteristics as those of the first to sixth embodiments can be obtained. In addition, as a power supply method, other methods such as two parallel wires are effective without changing the basic principle.

Further, in the above-described first to sixth embodiments, the configuration of a single antenna device that excites single polarization is shown, but an array antenna may be configured by arranging a plurality of such antenna devices. The arrangement at this time may be a triangular arrangement or a lattice-like square arrangement, and does not depend on the arrangement method.
As described above, by using the antenna device of the present invention as an antenna element, radiation from the feed line of each element can be suppressed, and the radiation mode from the feed line due to inter-element coupling, which is a problem in the conventional array antenna, can be suppressed. The degradation of the radiation pattern due to the influence can be suppressed, and the gain in the communication direction can be improved. Further, if the dipole antennas of the antenna device of the present invention are arranged orthogonally, both polarized waves can be excited.

[0057]

As described above, according to the present invention, the ground conductor, the first linear antenna provided at most about 1/8 wavelength above the ground conductor, and the first linear antenna A feed line that supplies power and is exposed above the ground conductor by a length up to the first linear antenna, and has a resonance frequency substantially the same as that of the first linear antenna, and is substantially parallel to the first linear antenna And a non-powered second linear antenna that is provided at a position approximately one-quarter wavelength away from the ground conductor above and is excited by an electromagnetic field effect from the first linear antenna. 1
Even if the length of the feed line for feeding the linear antenna is reduced, broadband characteristics can be obtained, and the amount of radiation from the feed line can be reduced. Thereby, a radiation pattern with good symmetry can be obtained, and there is an effect that cross polarization can be reduced.

According to the present invention, the second linear antenna is provided at a distance of about 1/4 wavelength from about 1/8 wavelength so as to be substantially parallel to the element length of the second linear antenna. Since there is provided at least one non-feeding third linear antenna that receives and excites the electromagnetic field from the two-wire antenna,
Since the third linear antenna operates as a director, directivity can be provided, and there is an effect that the gain in the communication direction can be improved.

According to the present invention, the second linear antenna has a resonance frequency higher than that of the second linear antenna, and is provided near the pole above the second linear antenna so as to be substantially parallel to the second linear antenna. Is provided with at least one non-feeding fourth linear antenna that is excited by receiving an electromagnetic field effect from the antenna device, so that resonance characteristics for a plurality of frequencies can be obtained, and an optimal antenna device according to the intended use of the antenna device The effect can be designed.

According to the present invention, the ground conductor, the first linear antenna provided at most approximately 1/8 wavelength above the ground conductor, and power is supplied to the first linear antenna, and A feed line that is exposed only to the length of the first linear antenna,
A parasitic antenna having substantially the same resonance frequency as the first linear antenna and excited by receiving an electromagnetic field effect from the first linear antenna, and substantially parallel to the first linear antenna. And at least two fifth linear antennas are provided at a position approximately 1/4 wavelength away from the ground conductor above the first linear antenna so as to be substantially symmetric with respect to the first linear antenna. Therefore, the same effect as in the above paragraph 0057 can be obtained, and the beam width of the H plane can be narrowed by arranging the unpowered fifth linear antenna in the H plane direction, thereby improving the gain in the communication direction. There is an effect that can be.

By adjusting the interval between the fifth linear antennas, a beam width substantially equal to the E-plane beam width can be obtained, and there is an effect that the occurrence of a gain difference depending on the communication direction can be suppressed.

According to the present invention, the width of the unpowered linear antenna is made larger than that of the first linear antenna that receives power, so that there is an effect that the broadband characteristics can be improved.

According to the present invention, since the both ends of the non-feeding linear antenna are bent toward the ground conductor so as to be substantially symmetrical with respect to the center, the beam width of the E plane can be increased. This has the effect of suppressing the occurrence of a gain difference depending on the communication direction.

Further, since the beam width can be adjusted by changing the angle of the inclination, there is an effect that the beam width can be used as a parameter for optimizing the antenna device so as to meet the intended purpose.

According to the present invention, since the linear antenna and the feed line are integrally formed on the dielectric substrate, the step of connecting the respective components can be omitted, so that the mass productivity of the device can be improved. There is an effect that can be done.

According to the present invention, claims 1 to 7 are provided.
Since a plurality of antenna devices according to any one of the above are arranged, deterioration of a radiation pattern due to an influence of a radiation mode from a feed line due to coupling between elements can be suppressed, and a gain in a communication direction can be improved. There is an effect that can be.

[Brief description of the drawings]

FIG. 1 is a perspective view showing a configuration of an antenna device according to a first embodiment of the present invention.

FIG. 2 is a graph showing a return loss with respect to a normalized frequency in the antenna device according to the first embodiment and other configurations.

FIG. 3 is a perspective view showing a configuration of an antenna device according to a second embodiment of the present invention.

FIG. 4 is a perspective view showing a configuration of an antenna device according to a third embodiment of the present invention.

FIG. 5 is a perspective view showing a configuration of an antenna device according to a fourth embodiment of the present invention.

FIG. 6 is a perspective view showing a configuration of an antenna device according to a fifth embodiment of the present invention.

FIG. 7 is a perspective view showing a configuration of an antenna device according to a sixth embodiment of the present invention.

FIG. 8 is a perspective view showing a configuration of a conventional antenna device.

[Explanation of symbols]

1 ground conductor, 2nd dipole antenna (1st linear antenna), 3 feed line, 4, 4a dielectric substrate,
5, 5a, 5b Second dipole antenna (second linear antenna), 6 third dipole antenna (third linear antenna), 7 fourth dipole antenna (4th linear antenna), 8 fifth Dipole antenna (fifth linear antenna).

Claims (8)

[Claims] 1. A ground conductor, a first linear antenna provided at a distance of at most about 1/8 wavelength above the ground conductor, and power is supplied to the first linear antenna. A feeder line that is exposed by the length up to the first linear antenna, and has a resonance frequency that is substantially the same as that of the first linear antenna, and has a resonance frequency that is substantially parallel to the first linear antenna. An antenna device comprising: a non-feeding second linear antenna that is provided at a position approximately 略 wavelength away from a ground conductor and is excited by receiving an electromagnetic field effect from the first linear antenna. A second linear antenna which is shorter than the element length of the second linear antenna and is provided at a distance of approximately 1/4 wavelength from approximately 1/8 wavelength so as to be substantially parallel to the second linear antenna; The antenna device according to claim 1, further comprising at least one non-feeding third linear antenna that is excited by receiving an electromagnetic action from the antenna. 3. An antenna having a resonance frequency higher than that of the second linear antenna, being provided in the vicinity of a pole above the second linear antenna so as to be substantially parallel to the second linear antenna. 2. The apparatus according to claim 1, further comprising at least one non-feeding fourth linear antenna which is excited by receiving a field effect.
The antenna device as described in the above. 4. A ground conductor, a first linear antenna provided at a distance of at most about 1/8 wavelength above the ground conductor, and power is supplied to the first linear antenna. A feeder line that is exposed only to the length of the first linear antenna; and a resonance line that has substantially the same resonance frequency as the first linear antenna, and is excited by an electromagnetic field from the first linear antenna. A feed linear antenna, which is substantially symmetric with respect to the first linear antenna at a position approximately 1/4 wavelength away from the ground conductor above the first linear antenna so as to be substantially parallel to the first linear antenna. An antenna device comprising at least two fifth linear antennas. 5. The antenna device according to claim 1, wherein the unpowered linear antenna is made thicker than the first linear antenna that receives power supply. 6. The antenna according to claim 1, wherein both ends of the non-feeding linear antenna are bent toward the ground conductor so as to be substantially symmetrical with respect to the center thereof. Item 10. 7. The antenna device according to claim 1, wherein the linear antenna and the feed line are formed integrally on a dielectric substrate. 8. An array antenna comprising a plurality of the antenna devices according to any one of claims 1 to 7.