JP2010124194A - Antenna device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To obtain a dual-frequency antenna omnidirectional in the horizontal plane, which is small-sized and low-cost and allows good antenna characteristics to be obtained regardless of two frequency bands that are separated from each other. <P>SOLUTION: In an antenna device, two first antenna conductors 1, which have a plurality of sheet-like conductors 11 for a first use frequency arranged and connected in series and are series power-fed and are located opposite to each other and two second antenna conductors 2, which have a plurality of sheet-like conductors 13 for a second use frequency arranged and connected in series and are series power-fed and are opposite to each other are installed around a columnar conductor 3; and a plane including a line of arrangement of two first antenna elements and a center axis of the columnar conductor and a plane, containing a line of arrangement of two second antenna elements and the center axis of the columnar conductor are orthogonal to each other. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a dual-frequency shared antenna whose vertical polarization is horizontal and omnidirectional, and more particularly to a collinear array antenna used for mobile communication base stations such as mobile phones, PHS, and WiMAX.

In mobile communication base stations such as mobile phones, PHS, and WiMAX, a circular area centered on the base station may be a service area. In this case, an antenna having a non-directional antenna with vertical polarization in the horizontal plane is often used as the base station antenna.
In recent years, with the spread of mobile phones, PHS, WiMAX, etc., many frequency bands such as 800 MHz band, 1.9 GHz band, 2 GHz band, 2.5 GHz band have been used in mobile communication. In order to reduce the size and cost, a frequency sharing antenna is required.
In addition, since a base station antenna must have a large gain, a collinear array antenna is generally used.

  In one example of a conventional dual-frequency omnidirectional antenna in a horizontal plane, four dipole antennas are installed in a horizontal plane to make it omnidirectional in the horizontal plane. The antenna is fed in parallel. In addition, each dipole antenna is shared with two frequencies by loading a non-excitation element or a slit (see, for example, Patent Document 1).

  In another example, three or more dipole antennas are installed in the horizontal plane to make the horizontal plane non-directional, and these dipole antennas are used as element antennas to feed each element antenna in parallel. In addition, each dipole antenna is shared with two frequencies by loading a non-excitation element (see, for example, Patent Document 2).

JP 2003-32034 A JP 2005-117493 A

  However, since the conventional dual-frequency horizontal omnidirectional antenna of Patent Document 1 and Patent Document 2 employs a parallel power feeding method, the size of the antenna increases due to the complexity of the power feeding circuit, resulting in high costs. There was a problem of becoming.

  Further, when the beam is directed in the horizontal plane, the element interval of the collinear array antenna needs to be 1 wavelength or less in order to suppress the generation of grating lobes. On the other hand, the length of the element antenna is about a half wavelength, and in order to reduce the coupling between elements, the element interval needs to be equal to or more than a half wavelength. In the conventional dual-frequency horizontal omnidirectional antennas of Patent Document 1 and Patent Document 2, each element antenna is shared by two frequencies, and therefore, when the two frequency bands are separated by 2 times or more, 2 There was a problem that the element spacing in one frequency band could not be more than half wavelength and not more than one wavelength.

  The present invention has been made to solve the above-described problems, and is small, low-cost, and omnidirectional in a horizontal plane for dual frequencies that can provide good antenna characteristics even when two frequency bands are separated from each other. It aims at obtaining a sex antenna.

  An antenna device according to the present invention includes an antenna including two first antenna conductors, two second antenna conductors, and a columnar conductor that is a ground conductor of the first antenna conductor and the second antenna conductor. In the apparatus, the first antenna conductor is composed of a sheet-like conductor having an electrical length of about ½ wavelength at a first use frequency, and the length direction is arranged in parallel to the central axis direction of the columnar conductor. A plurality of first element antennas connected in series with a sheet-like conductor having a first width smaller than the width of the first element antenna in series in the central axis direction. The sheet-like conductor having the first width is connected to the end of the first element antenna closest to the terminal end and arranged near the terminal end, and the second antenna conductor has a second operating frequency. In And a plurality of second element antennas having a length direction parallel to the central axis direction and a plurality of second element antennas. Element antennas are connected and arranged in series in the central axis direction by a sheet-like conductor having a second width smaller than the width of the second element antenna, and close to the end of the second element antenna closest to the end The sheet conductor having the second width is connected to the other end, and the first plane passing through the central axis of the columnar conductor intersects with a cylinder having a large diameter coaxial with the central axis of the columnar conductor. The first antenna conductor is installed on each line, and the second plane passing through the central axis of the columnar conductor and orthogonal to the first plane is coaxial with the central axis of the columnar conductor and has a large diameter. On the two second straight lines that intersect The second antenna conductor is installed, and the distance between the two first antenna conductors on the first straight line is ½ wavelength or less at the first use frequency, and the second straight line is on the second straight line. The distance between the two second antenna conductors is set to ½ wavelength or less at the second use frequency, and the two first antenna conductors are excited with the same amplitude and the same phase. The second antenna conductor is excited with the same amplitude and the same phase.

  In the antenna device according to the present invention, a first antenna conductor, which is two series-fed patch array antennas for the first use frequency, and two opposite use frequencies for the second use frequency are disposed around the columnar conductor. The second antenna conductor, which is a series-feed patch array antenna, is installed, and the straight line connecting the two first antenna elements and the straight line connecting the two second antenna elements are made vertical. Thus, it is possible to obtain a dual-frequency omnidirectional antenna in a horizontal plane that has good antenna characteristics even if the two frequency bands are separated from each other at low cost.

Embodiment 1 FIG.
FIG. 1A is a perspective view showing an antenna apparatus according to Embodiment 1 of the present invention. FIG.1 (b) is sectional drawing in a surface perpendicular | vertical to the central axis of the columnar conductor 3 of the antenna apparatus of Fig.1 (a).
An antenna apparatus according to Embodiment 1 of the present invention will be described with reference to FIG. The two frequencies used are f1 and f2.
In FIG. 1, a first antenna conductor 1 is a collinear array antenna for frequency f1, and a second antenna conductor 2 is a collinear array antenna for frequency f2. The cylindrical conductor 3 is a ground conductor for the first antenna conductor 1 and the second antenna conductor 2.

The first antenna conductor 1 employs, as an element antenna, patch conductors 11 that are sheet-like conductors having an electrical length of about ½ wavelength at the first use frequency f1, and n (n is 2 or more). (Integer) patch conductors 11. The patch conductor 11 is a plate that is bent in one direction, such as being cut from the side surface of a cylinder that is coaxial with the columnar conductor 3 and has a larger radius than the columnar conductor 3.
In addition, the two first antenna conductors 1 include two first antennas that intersect a cylinder whose first plane including the central axis of the columnar conductor 3 is coaxial with the columnar conductor 3 and whose radius is larger than the columnar conductor 3. This is an array antenna in which n patch conductors 11 are arranged in series such that center lines passing through the centers of the bent sides of the patch conductors 11 overlap each other on the line. Adjacent patch conductors 11 are connected by strip conductors 12. Further, the strip conductor 12 is connected to the end of the patch conductor 11 located farthest from the power supply end on the side opposite to the side where the patch conductor 11 immediately before the power supply end of the patch conductor 11 is present. Yes.
Further, the width Wf 1 of the patch conductor 11 is larger than the width of the strip conductor 12.

Similarly, the second antenna conductor 2 employs patch conductors 13 that are sheet-like conductors having an electrical length of about ½ wavelength at the frequency f2 as an element antenna, and m pieces (m is an integer of 2 or more). ) Patch conductor 13. The patch conductor 13 is a plate that is bent in one direction, such as being cut from the side surface of a cylinder that is coaxial with the columnar conductor 3 and has a larger radius than the columnar conductor 3.
The two second antenna conductors 2 include a cylinder having a central axis of the columnar conductor 3 and a second plane orthogonal to the first plane coaxial with the columnar conductor 3 and having a radius larger than that of the columnar conductor 3. This is an array antenna in which m patch conductors 13 are arranged in series so that the center lines passing through the centers of the curved sides of the patch conductors 13 overlap the two intersecting second lines. Adjacent patch conductors 13 are connected by strip conductors 14. Further, the strip conductor 14 is connected to the end of the patch conductor 13 located farthest from the power supply end on the side opposite to the side where the patch conductor 13 immediately before the power supply end of the patch conductor 13 is present. Yes.
Further, the width Wf2 of the patch conductor 13 is larger than the width of the strip conductor 14.
As described above, the first antenna conductor 1 and the second antenna conductor 2 are array antennas using a patch antenna as an element antenna and adopting a series feeding method.

  Next, the operation of the first antenna conductor 1 will be described. First, the operation of the patch conductor 11 will be described. When a signal reaches the patch conductor 11 from the strip conductor 12, the electrical length of the patch conductor 11 is about ½ wavelength at the frequency f1, so that the cavity formed by the patch conductor 11 and the cylindrical conductor 3 resonates. Part of the signal power is radiated to the outside. It can be considered that the patch conductor 11 having the impedance Z1 is connected in series on the feed line formed by the strip conductor 12 and the cylindrical conductor 3. The impedance Z1 increases as the width of the patch conductor 11 increases, and increases as the width of the strip conductor 12 decreases. That is, by changing the width of the patch conductor 11 and the width of the strip conductor 12, the impedance Z1 can be adjusted.

  The excitation method of the first antenna conductor 1 includes a traveling wave excitation and a standing wave excitation. When traveling wave excitation is performed, first, when a signal reaches the first patch conductor 11, a part of the power of the signal is radiated to the outside. A part of the remaining power is reflected to the feeding side, and the other is passed through the strip conductor 12 and becomes incident power to the next patch conductor 11. Thereafter, electric power is radiated from each patch conductor 11 on the same principle. When traveling wave excitation is performed, the real part of the impedance Z1 of the patch conductor 11 is large, and sufficient electric power is radiated to the outside of the antenna until the signal reaches the end of the first antenna conductor 1, or the first The terminal portion of the antenna conductor 1 must be matched and terminated.

  In the case of standing wave excitation, the real part of the impedance Z1 of the patch conductor 11 is reduced, and the input power reaches the terminal part of the first antenna conductor 1 sufficiently, whereupon the signal is reflected again to the patch conductor 11 side, It is superimposed on the input signal.

  Further, on the first antenna conductor 1, the electrical length between the midpoint in the length direction of the patch conductor 11 and the midpoint in the length direction of the adjacent patch conductor 11 is all set to one wavelength at the frequency f1. If the dimensions of the patch conductors 11 are the same, the patch conductors 11 are excited with the same amplitude and the same phase. In this case, the main beam is directed in the horizontal plane (in the xy plane in FIG. 1B).

  In addition, the electrical length between the midpoint in the length direction of the patch conductor 11 and the midpoint in the length direction of the adjacent patch conductor 11 is all the same, and is shorter or longer than one wavelength at the frequency f1. Then, the main beam can be tilted from the horizontal plane. When the main beam is tilted from the horizontal plane, the traveling wave is usually excited. This is because, when standing wave excitation is performed, a reflected wave from the terminal portion of the first antenna conductor 1 generates a beam in a direction symmetrical to the main beam with the horizontal plane as a symmetry plane.

  Although not shown in FIG. 1, signals are input to the two first antenna conductors 1 with the same amplitude and the same phase via the two distribution circuits. When only one first antenna conductor 1 is installed, the first antenna conductor 1 has directivity in a certain direction when viewed from the cylindrical conductor 3, but the two first antennas sandwich the cylindrical conductor 3. When the conductors 1 are installed facing each other and are fed with equal amplitude and the same phase, the directivity in the horizontal plane becomes almost omnidirectional.

  The operation of the first antenna conductor 1 has been described above. Similarly, for the second antenna conductor 2, the frequency f1 is set to the frequency f2, the patch conductor 11 is set to the patch conductor 13, the strip conductor 12 is set to the strip conductor 14, and the like. The operation can be described by replacing the impedance Z1 of the patch conductor 11 with the impedance Z2 of the patch conductor 13.

  In order to reduce the coupling amount, the two first antenna conductors 1 and the two second antenna conductors 2 include a straight line connecting the two first antenna conductors 1 with the cylindrical conductor 3 interposed therebetween, and two second antenna conductors 1 The straight lines connecting the two antenna conductors 2 are installed at right angles.

  For example, f2 = 0.74f1, and the first antenna conductor 1 is an array antenna in which twelve patch conductors 11 are arranged, and the second antenna conductor 2 is an array antenna in which twelve patch conductors 13 are arranged. Think about the case. FIG. 2 shows the calculation result of the radiation pattern in the horizontal plane when each patch conductor 11 is excited with the same amplitude and same phase and each patch conductor 13 is also excited with the same amplitude and same phase. It can be seen that the frequencies f1 and f2 are almost omnidirectional in the horizontal plane. In FIG. 2, the difference between the maximum gain and the minimum gain in the horizontal plane is 2.2 dB at the frequency f1 and 1.5 dB at the frequency f2.

  As the distance between the two opposing first antenna conductors 1 and the distance between the two opposing second antenna conductors 2 are increased, the difference between the maximum gain and the minimum gain in the horizontal plane increases. For this reason, at least the distance between the two first antenna conductors 1 facing each other needs to be a half wavelength or less at the frequency f1, and the distance between the two second antenna conductors 2 facing each other needs to be a half wavelength or less at the frequency f2.

  In the antenna device according to the first embodiment, the two first antenna conductors 1 for f1 and the two second antenna conductors 2 for f2 are separately installed. The interval between the patch conductors 11 and the interval between the patch conductors 13 of the second antenna conductor 2 can be set to different values. Therefore, even if f1 and f2 are separated from each other by a factor of two or more, the element antenna interval can be set to an optimum value in each of f1 and f2.

Even if the cylindrical conductor 3 is a columnar conductor having an arbitrary shape such as a square cross section, the operation principle is the same as that of the first embodiment, and the same effect can be obtained.
Moreover, the dimension of each patch conductor 11 does not need to be the same, and the dimension of each patch conductor 13 does not need to be the same.

  As described above, the first antenna conductor 1 that is two series-fed patch array antennas for the frequency f1 and the two opposing antennas for the frequency f2 are disposed around the cylindrical conductor 3 that is the ground conductor. By installing a series-fed patch array antenna and making the straight line connecting the two array antennas for f1 and the straight line connecting the two array antennas for f2 small, low cost, and two frequencies Even if the bands are separated from each other, there is an effect that an omnidirectional antenna in a horizontal plane for two frequencies having good antenna characteristics can be obtained.

Embodiment 2. FIG.
FIG. 3A is a perspective view showing an antenna apparatus according to Embodiment 2 of the present invention. FIG. 3B is a cross-sectional view taken along a plane perpendicular to the central axis of the columnar conductor 3 of the antenna device of FIG.
The antenna device according to the second embodiment of the present invention is the same as the antenna device according to the first embodiment of the present invention except that the non-excitation elements 21 and 22 are added. The same reference numerals are given and description thereof is omitted.

The non-excitation element 21 is a plate that is bent in one direction, such as being cut from the side of a cylinder that is coaxial with the columnar conductor 3 and has a radius that is larger than the radius of the bent side of the patch conductor 11, and has an electrical length at the frequency f1. Is about 1/2 wavelength long.
The n non-excitation elements 21 intersect a cylinder whose first plane including the central axis of the columnar conductor 3 is coaxial with the columnar conductor 3 and whose radius is larger than the radius of the curved side of the patch conductor 11. The two third lines are arranged in series so that a center line passing through the center of the bent side overlaps.

The non-excitation element 22 is a plate that is bent in one direction, such as being cut from the side surface of a cylinder that is coaxial with the columnar conductor 3 and has a radius that is larger than the radius of the bent side of the patch conductor 13, and has an electrical length at a frequency f2. Is about 1/2 wavelength long.
The m non-excitation elements 22 intersect a cylinder whose second plane including the central axis of the columnar conductor 3 is coaxial with the columnar conductor 3 and whose radius is larger than the radius of the curved side of the patch conductor 13. The two fourth lines are arranged in series so that a center line passing through the center of the bent side overlaps.

  Thus, when the non-excitation element 21 is installed in the vicinity of the patch conductor 11, a kink (Kink: knot-like locus) due to double resonance is generated in the Smith chart of the impedance of the patch conductor 11. By this kink, the input impedance characteristic of the first antenna conductor 1 can be widened.

  Similarly, when the non-excitation element 22 is installed in the vicinity of the patch conductor 13, a kink (Kink: knot-like locus) due to double resonance occurs in the Smith chart of the impedance of the patch conductor 13. By this kink, the input impedance characteristic of the second antenna conductor 2 can be widened.

In the antenna device according to the second embodiment, the center line passing through the center of the side where the plurality of non-excitation elements 21 are bent overlaps with the third line included in the first plane. Although it is arranged, it is not limited to this. Further, the plurality of non-excitation elements 22 are arranged so that the center line passing through the center of the bent side overlaps the fourth line included in the second plane, but the present invention is not limited to this. .
In the antenna device according to the second embodiment, one non-excitation element 21 is provided for each patch conductor 11, but two or more may be provided. Similarly, one non-excitation element 22 is provided for each patch conductor 13, but two or more non-excitation elements 22 may be provided.

  As described above, by providing at least one non-excitation element 21 in the vicinity of each patch conductor 11 and at least one non-excitation element 22 in the vicinity of each patch conductor 13, it has a wide-band input impedance characteristic. An effect is obtained in that an omnidirectional antenna in a horizontal plane shared by two frequencies can be obtained.

Embodiment 3 FIG.
FIG. 4A is a perspective view showing an antenna apparatus according to Embodiment 3 of the present invention. FIG. 4B is a cross-sectional view taken along a plane perpendicular to the central axis of the columnar conductor 3 of the antenna device of FIG.
The antenna device according to the third embodiment of the present invention is the same as the antenna device according to the first embodiment of the present invention except that non-excitation elements 23 and 24 are added. The same reference numerals are given and description thereof is omitted.

The non-excitation element 23 is a plate that is bent in one direction, such as being cut from a side surface of a cylinder that is coaxial with the columnar conductor 3 and has the same radius as that of the side of the patch conductor 11 that is bent, and has an electrical length at the frequency f1. Is about 1/2 wavelength long.
The 2 × n non-excitation elements 23 have a third plane that does not intersect the patch conductor 11 including the central axis of the cylindrical conductor 3 coaxial with the cylindrical conductor 3 and a radius of the patch conductor 11. The n lines are arranged in series so that the center line passing through the center of the curved side overlaps the two fifth lines intersecting the cylinder having the same side radius.
Further, the 2 × n non-excitation elements 23 have a fourth plane that does not cross the patch conductor 11 including the central axis of the columnar conductor 3 and does not contact the third plane and is coaxial with the columnar conductor 3 and has a radius. The patch conductors 11 are arranged in series in series so that the center line passing through the center of the bent side overlaps the two sixth lines intersecting with the same cylinder as the radius of the bent side of the patch conductor 11.

The non-exciting element 24 is a plate bent in one direction that is coaxial with the columnar conductor 3 and whose radius is cut from the side surface of the same cylinder as the radius of the bent side of the patch conductor 13, and has an electrical length at the frequency f2. Is about 1/2 wavelength long.
The 2 × m non-exciting elements 24 are patch conductors 11 and 13 including the central axis of the cylindrical conductor 3 and the fifth plane not intersecting the non-exciting element 23 is coaxial with the cylindrical conductor 3 and has a radius of patch. M conductors are arranged in series so that the center line passing through the center of the bent side overlaps the two seventh lines intersecting with the same cylinder as the radius of the bent side of the conductor 13.
In addition, the 2 × m number of non-excitation elements 24 have a cylindrical shape in which the sixth plane that does not cross the patch conductors 11 and 13 and the non-excitation element 23 including the central axis of the cylindrical conductor 3 and does not contact the fifth plane is cylindrical. In series so that the center line passing through the center of the bent side overlaps with two seventh lines that are coaxial with the conductor 3 and have the same radius as the radius of the bent side of the patch conductor 13. m pieces are arranged.

  In the antenna device according to the third embodiment, two non-excitation elements 23 are provided for each patch conductor 11, but three or more may be provided. Similarly, two non-excitation elements 24 are provided for each patch conductor 13, but three or more may be provided.

  Thus, when the non-excitation element 23 is installed in the vicinity of the patch conductor 11, a kink (Kink: knot-like trajectory) due to double resonance occurs in the Smith chart of the impedance of the patch conductor 11. By this kink, the input impedance characteristic of the first antenna conductor 1 can be widened.

  Similarly, when the non-excitation element 23 is installed in the vicinity of the patch conductor 13, a kink (Kink: knot-like trajectory) due to double resonance occurs in the Smith chart of the impedance of the patch conductor 13. By this kink, the input impedance characteristic of the second antenna conductor 2 can be widened.

  Further, since the patch conductor 11, the strip conductor 12, the patch conductor 13, the strip conductor 14, the non-exciting element 23, and the non-exciting element 24 are installed on a cylinder separated from the columnar conductor 3 by a predetermined value D, for example, A film substrate is placed on a cylindrical insulator having a thickness D surrounding the columnar conductor 3, and the patch conductor 11, strip conductor 12, patch conductor 13, strip conductor 14, non-exciting element 23, non-exciting element are provided on the film substrate. By making the element 24, it can manufacture integrally and can reduce manufacturing cost.

  As described above, a plurality of non-exciting elements 23 are installed in the vicinity of each patch conductor 11, and a plurality of non-exciting elements 24 are installed in the vicinity of each patch conductor 13, and the patch conductor 11, patch conductor 13, non-exciting element 23, By disposing the non-excitation element 24 on the same cylinder, there is an effect that a low-cost dual-frequency horizontal omnidirectional antenna having a wide-band input impedance characteristic can be obtained.

Embodiment 4 FIG.
FIG. 5A is a perspective view showing an antenna apparatus according to Embodiment 4 of the present invention. FIG. 5B is a cross-sectional view taken along a plane perpendicular to the central axis of the columnar conductor 3 of the antenna device of FIG.
The antenna device according to the fourth embodiment of the present invention is the same as the antenna device according to the first embodiment of the present invention except that the dielectric 31 is added. Additional description will be omitted.

  In FIG. 5, the dielectric 31 is installed between the two first antenna conductors 1, the two second antenna conductors 2, and the columnar conductor 3. In addition, you may install in the part between the two 1st antenna conductors 1, the 2nd 2nd antenna conductor 2, and the cylindrical conductor 3. FIG.

  By installing the dielectric 31, the first antenna conductor 1 and the second antenna conductor 2 can be formed on the dielectric 31, so that the assembly cost is reduced. For example, a manufacturing method in which the first antenna conductor 1 and the second antenna conductor 2 are manufactured by being integrated on a film substrate by etching and the film substrate is wound around a dielectric 31 is conceivable.

  As described above, the dielectric 31 is provided in part or all between the two first antenna conductors 1, the two second antenna conductors 2, and the cylindrical conductor 3. It has the effect that a non-directional antenna in the horizontal plane for frequency sharing can be obtained.

  In the antenna device according to the fourth embodiment, the dielectric 31 is applied to the antenna device according to the first embodiment. However, the above-described effects can be obtained even when applied to the antenna devices according to the second and third embodiments. be able to.

Embodiment 5 FIG.
6A and 6B are diagrams showing an antenna device according to Embodiment 5 of the present invention, in which FIG. 6A shows an open termination, FIG. 6B shows a short-circuit termination, and FIG. Indicates the case of matching termination.
The antenna device according to Embodiment 5 of the present invention differs from the antenna device according to Embodiment 1 of the present invention in that load impedance is loaded at the terminal ends of the first antenna conductor 1 and the second antenna conductor 2 of the antenna device, Since other than that is the same, the same code | symbol is attached | subjected to the same part and description is abbreviate | omitted.

In FIG. 6, the conductor plate 32 connects the strip conductor 12 and the cylindrical conductor 3 at the terminal end of the first antenna conductor 1, and the conductor plate 33 connects the strip conductor 14 and the circle at the terminal end of the second antenna conductor 2. The columnar conductor 3 is connected.
The chip resistor 34 is connected to the strip conductor 12 and the columnar conductor 3 by soldering or the like at the terminal end of the first antenna conductor 1, and the chip resistor 35 is connected to the strip conductor at the terminal end of the second antenna conductor 2. 14 and the columnar conductor 3 are connected by soldering or the like.

  In the case where the first antenna conductor 1 and the second antenna conductor 2 are excited by standing waves, they are set as open ends or short-circuit ends. In this case, the electrical length from the midpoint of the length of the patch conductor 11 closest to the end of the first antenna conductor 1 to the end of the first antenna conductor 1 is expressed as (2k−1) at f1 at the open end. ) / 4 wavelength, and (2k) / 4 wavelength at f1 at the time of short-circuit termination. Here, k is an integer of 1 or more.

  Similarly, the electrical length from the midpoint in the length direction of the patch conductor 13 closest to the end of the second antenna conductor 2 to the end of the second antenna conductor 2 is expressed as (2k−1) at f2 at the open end. ) / 4 wavelength, and (2k) / 4 wavelength at f2 at the time of short-circuit termination.

  In this way, the reflected wave and the incident wave from the terminal portion are overlapped in phase in the patch conductors 11 and 13. That is, since the power reflected by the terminal portion without being radiated is re-radiated, the radiation efficiency can be increased.

  When the first antenna conductor 1 and the second antenna conductor 2 are subjected to traveling wave excitation, they are matched terminations. For example, in the case where the main beam is tilted from the horizontal plane, if the power remaining without being radiated to the terminal portions of the first antenna conductor 1 and the second antenna conductor 2 is reflected by the terminal portions, With the horizontal plane as the symmetry plane, the beam is also generated in a direction symmetrical to the main beam.

  Therefore, the strip conductor 12 at the end of the first antenna conductor 1 and the cylindrical conductor 3 are connected via the chip resistor 34, and the strip conductor 14 at the end of the second antenna conductor 2 and the cylindrical conductor 3 are connected to the chip. By connecting via the resistor 35 and making the matching termination, reflection at the terminal portions of the first antenna conductor 1 and the second antenna conductor 2 can be eliminated, and unnecessary radiation can be reduced.

  As described above, by loading the first antenna conductor 1 and the second antenna conductor 2 with load impedances that are open, short-circuited or matched terminations, radiation efficiency is high and unnecessary radiation is reduced 2. It has the effect that a non-directional antenna in the horizontal plane for frequency sharing can be obtained.

  In the antenna device according to the fifth embodiment, the load impedance loading is applied to the antenna device according to the first embodiment. However, even when the antenna device according to the second, third, and fourth embodiments is applied, There is an effect.

Embodiment 6 FIG.
FIG. 7A is a perspective view showing an antenna apparatus according to Embodiment 6 of the present invention. FIG. 7B is a cross-sectional view taken along a plane perpendicular to the central axis of the columnar conductor 3 of the antenna device of FIG.
The antenna device according to the sixth embodiment of the present invention is the same as the antenna device according to the first embodiment of the present invention except that a dielectric radome 36 is added. The description is omitted.

  In FIG. 7, reference numeral 36 denotes a dielectric radome that covers the cylindrical conductor 3, the first antenna conductor 1, and the second antenna conductor 2. By installing the dielectric radome 36, it is possible to prevent the antenna device from being deformed or damaged due to the influence of rain or snow. Further, since the base station antenna is installed at a high place such as the roof of a building, the antenna strength against the wind pressure load is important. By installing the dielectric radome 36, the antenna strength against the wind pressure load can be improved.

  In FIG. 7, a cylindrical dielectric is assumed as the dielectric radome 36, but the cross section may be an arbitrary shape such as a square.

  As described above, by providing the dielectric radome that covers the cylindrical conductor 3, the first antenna conductor 1 and the second antenna conductor 2, a dual-frequency horizontal omnidirectional antenna with strong antenna strength can be obtained. It has the effect.

It is the perspective view (a) of the antenna apparatus which concerns on Embodiment 1 of this invention, and sectional drawing (b) in a surface perpendicular | vertical to the central axis of the columnar conductor of an antenna apparatus. It is a radiation pattern figure in a horizontal surface when each patch conductor is excited by equal amplitude and the same phase. It is the perspective view (a) of the antenna device which concerns on Embodiment 2 of this invention, and sectional drawing (b) in a surface perpendicular | vertical to the central axis of the cylindrical conductor of an antenna device. It is the perspective view (a) of the antenna device which concerns on Embodiment 3 of this invention, and sectional drawing (b) in a surface perpendicular | vertical to the central axis of the columnar conductor of an antenna device. It is the perspective view (a) of the antenna device which concerns on Embodiment 4 of this invention, and sectional drawing (b) in a surface perpendicular | vertical to the central axis of the columnar conductor of an antenna device. It is a perspective view of the antenna apparatus which concerns on Embodiment 5 of this invention. It is the perspective view (a) of the antenna device which concerns on Embodiment 6 of this invention, and sectional drawing (b) in a surface perpendicular | vertical to the central axis of the columnar conductor of an antenna device.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 1st antenna conductor, 2nd 2nd antenna conductor, 3 cylindrical conductor, 11, 13 patch conductor, 12, 14 strip conductor, 21, 22, 23, 24 non-excitation element, 31 dielectric, 32, 33 conductor Plate, 34, 35 Chip resistor, 36 Dielectric radome.

Claims (8)

In an antenna device comprising two first antenna conductors, two second antenna conductors, and a columnar conductor that is a ground conductor of the first antenna conductor and the second antenna conductor,
The first antenna conductor is composed of a sheet-like conductor having an electrical length of about ½ wavelength at a first use frequency, and a plurality of lengths are arranged in parallel to the central axis direction of the columnar conductor. A plurality of first element antennas connected in series in the central axis direction by a sheet-like conductor having a first width smaller than the width of the first element antenna. The sheet-like conductor having the first width is connected to an end portion closer to the end of the first element antenna closest to the end,
The second antenna conductor is composed of a sheet-like conductor having an electrical length of about ½ wavelength at a second use frequency, and a plurality of second antenna conductors arranged in parallel with the central axis direction. A plurality of the second element antennas are connected and arranged in series in the central axis direction by a sheet-like conductor having a second width smaller than the width of the second element antenna. The sheet-like conductor of the second width is connected to the end portion of the second element antenna closest to the end of the second element antenna,
The first antenna conductors are respectively installed on two first lines where a first plane passing through the central axis of the columnar conductor intersects a cylinder having a large diameter coaxial with the central axis of the columnar conductor;
The second plane passing through the central axis of the columnar conductor and orthogonal to the first plane intersects with the second axis on the two second straight lines that are coaxial with the central axis of the columnar conductor and intersect a cylinder having a large diameter. The antenna conductor of
The distance between the two first antenna conductors on the first straight line is ½ wavelength or less at the first use frequency,
The distance between the two second antenna conductors on the second straight line is ½ wavelength or less at the second use frequency,
Exciting the two first antenna conductors with equal amplitude and same phase;
An antenna device, wherein two of the second antenna conductors are excited with the same amplitude and the same phase. The shape of all the first element antennas of the first antenna conductor is the same;
The antenna device according to claim 1, wherein all the second element antennas of the second antenna conductor have the same shape. The columnar conductor is a cylinder,
The two first antenna conductors and the two second antenna conductors are disposed at a cylindrical position coaxial with the columnar conductor and having a diameter larger than the diameter of the columnar conductor by a predetermined value. The antenna device according to claim 1 or 2. In the vicinity of the first element antenna, a plurality of conductors having an electrical length of about ½ wavelength at the first use frequency are installed,
4. The antenna device according to claim 1, wherein a plurality of conductors having an electrical length of about ½ wavelength at the second use frequency are provided in the vicinity of the second element antenna. 5. . In the vicinity of the first element antenna and at the position of a cylinder coaxial with the columnar conductor and having a diameter larger than the diameter of the columnar conductor by a predetermined value, the electrical length at the first operating frequency is about ½ wavelength. Install multiple conductors of
In the vicinity of the second element antenna and at the position of a cylinder coaxial with the columnar conductor and having a diameter larger than the diameter of the columnar conductor by a predetermined value, the electrical length at the second operating frequency is about ½ wavelength. The antenna device according to claim 3, wherein a plurality of conductors are provided.   6. A dielectric material is provided on a part or all of the two first antenna conductors and between the two second antenna conductors and the columnar conductor. The antenna device described. Loading the terminal impedance of the first antenna conductor with a load impedance to be open, short-circuited or matched termination;
The antenna device according to any one of claims 1 to 6, wherein a load impedance for opening, short-circuiting, or matching termination is loaded on a terminal portion of the second antenna conductor.   8. The antenna device according to claim 1, further comprising a dielectric radome that covers the columnar conductor, the first antenna conductor, and the second antenna conductor.

Images