Dipole antenna and antenna device

Abstract

An antenna element that can be miniaturized while suppressing deterioration of frequency characteristics due to interference between antennas of different frequency bands is provided. [Solution] A dipole antenna comprising four radiating sections (110a-110d) arranged in a rectangular shape, and four power feed sections (120a-120d) arranged at each corner of the rectangle formed by the four radiating sections (110a-110d) to feed power to the two radiating sections (110a-110d) on either side of each corner, wherein a power feed voltage from one set of power feed sections (120a-120d) arranged at two opposing corners to the four radiating sections (110a-110d) corresponds to one of two orthogonal polarized waves, and a power feed voltage from another set of power feed sections (120a-120d) arranged at two opposing corners to the four radiating sections (110a-110d) corresponds to the other of the two orthogonal polarized waves.

Description

[Technical Field]

[0001] The present invention relates to a dipole antenna and an antenna device. [Background technology]

[0002] 2. Description of the Related Art In order to support a wide frequency band, an antenna device used in a base station or the like is often configured by combining several types of antenna elements each corresponding to a different frequency band.

[0003] Patent Document 1 discloses a multi-band multi-polarized wireless communication antenna including a reflector, at least one first radiation module of a first band installed on the reflector, and at least one second or third radiation module of a second band or a third band installed on the reflector, wherein the second or third radiation module is installed so as to be included within the installation range of the first radiation module. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Special Publication No. 2016-534598 Summary of the Invention [Problem to be solved by the invention]

[0005] Antenna devices are required to be smaller in size in order to reduce installation work and reduce the effects of wind after installation, etc. In antenna devices that combine multiple antennas corresponding to different frequency bands, it is required to achieve further miniaturization while reducing interference between the antennas.

[0006] The present invention aims to provide an antenna device and antenna element that combine multiple antennas corresponding to different frequency bands, which can be made smaller while suppressing deterioration of frequency characteristics due to interference between antennas of different frequency bands. [Means for solving the problem]

[0007] The present invention, which achieves the above object, A dipole antenna, Four radiating parts arranged in a rectangular shape, four feeding units arranged at each corner of a rectangle formed by the four radiating units, feeding power to two radiating units sandwiching each corner; The antenna responds to one of two orthogonal polarized waves by feeding voltage from a pair of feed points located at two opposing corners to four radiating points. This is a dipole antenna that responds to the other of the two orthogonal polarized waves by feeding voltage to four radiating sections from another set of feeding sections located at two opposite corners different from the two corners. More specifically, each of the four radiation portions may have a choke structure in which a portion of the conductor wiring is bent. More specifically, each of the four radiating portions may have a coupling structure with a wider wiring width at both ends of the choke structure. Alternatively, two systems of feed lines may be split into two, each extending from the center of a rectangle formed by the four radiating sections toward two sets of opposing corners of the rectangle, with power being supplied from each of the four feed sections to the two radiating sections that sandwich the feed section. More specifically, in the power supply section, the power supply line may be configured as an open stub. Also, a leg portion rising from the power supply circuit board having the power supply port; Four arms extending in all directions from the upper ends of the legs; a rectangular portion connecting the ends of the four arms, Two power supply lines are wired to the legs and arms, A configuration in which four radiating portions are formed in the rectangular portion may also be used. The legs are made of a single board. Of the two feeder lines, one may be split into two at the lower end of the leg, and the other may be split into two at the upper end of the leg. Furthermore, the present invention, which achieves the above object, a first antenna element constituted by the dipole antenna; a second antenna element corresponding to a different frequency band than the first antenna element; a reflector to which the first antenna element and the second antenna element are attached; The antenna device is provided with: Here, the first antenna element may be configured to support a lower frequency band than the second antenna element. The second antenna element may also be configured to form an array antenna with a plurality of antenna elements arranged on a reflector. The second antenna element may be arranged closer to the reflector than the first antenna element. [Effects of the Invention]

[0008] According to the present invention, in an antenna device that combines multiple antennas corresponding to different frequency bands and the antenna elements that constitute this antenna device, it is possible to achieve miniaturization while suppressing degradation of frequency characteristics due to interference between antennas of different frequency bands. [Brief explanation of the drawings]

[0009] [Figure 1] 1 is a diagram illustrating a configuration of an antenna device according to an embodiment of the present invention. [Figure 2] 3A and 3B are diagrams illustrating a model and an operation principle of a first antenna element. [Figure 3] 3A and 3B are diagrams showing the outer shape and arrangement of the first antenna element, where FIG. 3A is a diagram of the antenna device shown in FIG. 1 viewed from the x direction, and FIG. 3B is a diagram of the antenna device shown in FIG. 1 viewed from the z direction. [Figure 4] 1. FIG. 4 is a diagram in which the rectangular portion and the arm portion of the first antenna element shown in FIG. 3 are extracted, and is a diagram seen from the front of FIG. 3(A) (the x-direction side shown in FIG. 1). [Figure 5] 4(A) is a diagram in which the rectangular portion and the arm portion of the first antenna element shown in FIG. 3 are extracted, and is a diagram seen from the back side of FIG. 3(A). [Figure 6] FIG. 5 is an enlarged view of part A in FIG. 4. [Figure 7] FIG. 2 is a diagram illustrating a configuration of a radiation unit. [Figure 8] 8A and 8B are diagrams showing the structure of the choke section and coupling section of the radiating section, where FIG. 8A shows the wiring on the front side of the rectangular section, FIG. 8B shows the wiring on the back side of the rectangular section, and FIG. 8C shows the circuit configuration realized by the choke section and coupling section. [Figure 9] 1(B) is a diagram of the leg portion of the first antenna element shown in FIG. 3, as viewed from the front of FIG. 3(B) (the z direction side shown in FIG. 1). [Figure 10] 4 is a diagram of the leg portion of the first antenna element shown in FIG. 3, as seen from the back side of FIG. 3(B). [Figure 11] FIG. 4 is a diagram showing a feeder circuit board of the first antenna element. [Figure 12] 12A and 12B are diagrams showing examples of the radiation pattern of the second antenna element, where FIG. 12A shows the radiation pattern when the first antenna element is not present, FIG. 12B shows the radiation pattern when the first antenna element is present, and FIG. 12C is a graph showing the amount of change (difference) between the pattern in FIG. 12A and the pattern in FIG. 12B. [Figure 13] 13A and 13B are diagrams showing the influence of a low-band element on the radiation pattern of a middle-band element, where FIG. 13A shows the amount of pattern change when a first antenna element is used as the low-band element, and FIG. 13B shows the amount of pattern change when a cross dipole element is used as the low-band element. [Figure 14] 14A and 14B are diagrams showing the VSWR of antenna elements in an antenna device, where FIG. 14A is a diagram showing the VSWR of a first antenna element, and FIG. 14B is a diagram showing the VSWR of a second antenna element. [Figure 15] 15(A) and 15(B) are diagrams showing radiation patterns in the horizontal plane for a set of second antenna elements when a first antenna element is present, where FIG. 15(A) is a diagram showing a radiation pattern at a frequency of 1.7 GHz, FIG. 15(B) is a diagram showing a radiation pattern at a frequency of 1.9 GHz, FIG. 15(C) is a diagram showing a radiation pattern at a frequency of 2.1 GHz, FIG. 15(D) is a diagram showing a radiation pattern at a frequency of 2.3 GHz, FIG. 15(E) is a diagram showing a radiation pattern at a frequency of 2.5 GHz, and FIG. 15(F) is a diagram showing a radiation pattern at a frequency of 2.7 GHz. [Figure 16] 16(A) and 16(B) are diagrams showing radiation patterns in the horizontal plane for a set of second antenna elements when there is no second antenna element, where FIG. 16(A) is a diagram showing a radiation pattern at a frequency of 1.7 GHz, FIG. 16(B) is a diagram showing a radiation pattern at a frequency of 1.9 GHz, FIG. 16(C) is a diagram showing a radiation pattern at a frequency of 2.1 GHz, FIG. 16(D) is a diagram showing a radiation pattern at a frequency of 2.3 GHz, FIG. 16(E) is a diagram showing a radiation pattern at a frequency of 2.5 GHz, and FIG. 16(F) is a diagram showing a radiation pattern at a frequency of 2.7 GHz. [Figure 17] 17A and 17B are diagrams showing the effect of a low-band element on the radiation pattern of a middle-band element through simulation, where FIG. 17A shows the amount of pattern change in +45° polarization, and FIG. 17B shows the amount of pattern change in -45° polarization. [Figure 18] 18A and 18B are diagrams showing the effect of a low-band element on the radiation pattern of a middle-band element using actual measured values, where FIG. 18A shows the amount of pattern change in +45° polarization, and FIG. 18B shows the amount of pattern change in -45° polarization. [Figure 19] FIG. 10 is a diagram illustrating a configuration example of a cross dipole element. DETAILED DESCRIPTION OF THE INVENTION

[0010] Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings.

[0011] <Configuration of the antenna device> Fig. 1 is a diagram showing the configuration of an antenna device according to this embodiment. The antenna device 10 shown in Fig. 1 is configured by arranging a first antenna element 100 and a second antenna element 200 on one side of a plate-shaped base 300. Hereinafter, when there is no need to distinguish between the first antenna element 100 and the second antenna element 200, they will be referred to as "antenna elements 100, 200." A reflector is provided on the side of the base 300 where the antenna elements 100, 200 are arranged. Although not shown, a cover is attached to the antenna device 10 so as to cover the arrangement of the antenna elements 100, 200.

[0012] The first antenna element 100 and the second antenna element 200 correspond to different frequency bands. Here, it is assumed that the first antenna element 100 corresponds to a low band frequency band, and the second antenna element 200 corresponds to a middle band frequency band. Examples of the low band include the 0.7 GHz band, the 0.8 GHz band, and the 0.9 GHz band. Examples of the middle band include the 1.5 GHz band, the 1.7 GHz band, the 2.0 GHz band, the 2.3 GHz band, and the 2.5 GHz band.

[0013] In the example shown in Fig. 1, one first antenna element 100 and six second antenna elements 200 are provided on a base 300. The second antenna elements 200 are arranged in two rows of three on each side of the first antenna element 100. In Fig. 1, the six second antenna elements 200 are individually given suffixes a to f. When distinguishing between the individual second antenna elements 200, the suffixes a to f may be added and the elements may be referred to as second antenna element 200a, second antenna element 200b, etc.

[0014] Comparing the first antenna element 100 and the second antenna element 200, the first antenna element 100 is disposed at a higher position than the second antenna element 200. In other words, the first antenna element 100 is farther from the reflector of the base 300 than the second antenna element 200.

[0015] The first antenna element 100 is a dipole antenna, and one element provides 2MIMO (Multiple-Input and Multiple-Output). Details of the first antenna element 100 will be described later. The configuration of the second antenna element 200 is not particularly limited, but may be, for example, a dipole antenna. The second antenna element 200 is configured, for example, by combining two orthogonal elements to provide 2MIMO with one element.

[0016] <Operation Principle of the First Antenna Element 100> FIG. 2 is a diagram illustrating a model and operating principle of the first antenna element 100. For comparison, FIG. 2 also includes a diagram illustrating a model and operating principle of a cross dipole element, which is a common configuration of a 2-MIMO antenna element. As shown in FIG. 2, a cross dipole element is configured by combining two dipole elements that are orthogonal to each other, as shown in the element model. Two orthogonal polarized waves (here, -45° and +45°) operate independently in the two dipole elements. In the example of the operating principle shown in FIG. 2, a -45° polarized wave is generated in the dipole element (a) illustrated upward to the right, and a +45° polarized wave is generated in the dipole element (b) illustrated downward to the right.

[0017] On the other hand, as shown in the element model, the first antenna element 100 is configured by combining four radiating units into a rectangular shape. In this first antenna element 100, power feed units are arranged at the four corners. Then, by applying a feed voltage from the power feed units arranged at two diagonally opposite corners of the rectangle formed by the four radiating units, two-directional polarized waves (-45° and +45°) operate in the four radiating units. In the example of the operating principle shown in Figure 2, it is shown that applying a feed voltage from the top left and bottom right feed units generates a -45° polarized wave, and applying a feed voltage from the top right and bottom left feed units generates a +45° polarized wave.

[0018] <Configuration of first antenna element 100> Figure 3 is a diagram showing the outer shape and arrangement of the first antenna element 100. Figure 3(A) is a diagram showing the antenna device 10 shown in Figure 1 as seen from the x direction, and Figure 3(B) is a diagram showing the antenna device 10 shown in Figure 1 as seen from the z direction. However, in Figures 3(A) and 3(B), the second antenna element 200 is omitted from the illustration.

[0019] The first antenna element 100 has a feeder circuit board 150 attached to a base 300, legs 140 rising vertically (in the x direction in FIG. 1 ) from the feeder circuit board 150, arms 130 extending in all directions from the top ends of the legs 140, and a rectangular portion 110 connecting the ends of the arms 130. Each of these parts is made of a dielectric substrate, and wiring is formed on the surface of the dielectric substrate. The wiring on the dielectric substrate is formed, for example, of a copper foil pattern.

[0020] Figures 4 and 5 are diagrams illustrating the rectangular portion 110 and the arm portion 130 of the first antenna element 100 shown in Figure 3. Figure 4 is a diagram viewed from the front of Figure 3(A) (the x-direction side shown in Figure 1), and this surface will hereinafter be referred to as the front surface. Figure 5 is a diagram viewed from the back of Figure 3(A), and this surface will hereinafter be referred to as the back surface.

[0021] As shown in FIG. 4, rectangular portion 110 is composed of four radiating portions 110a, 110b, 110c, and 110d. Power feeding portions 120a, 120b, 120c, and 120d are provided at the four corners of rectangular portion 110. In the example shown in FIG. 4, power feeding portion 120a is provided at the corner between radiating portion 110d and radiating portion 110a. Power feeding portion 120b is provided at the corner between radiating portion 110a and radiating portion 110b. Power feeding portion 120c is provided at the corner between radiating portion 110b and radiating portion 110c. Power feeding portion 120d is provided at the corner between radiating portion 110c and radiating portion 110d. Hereinafter, when there is no need to distinguish between the power supply units 120a, 120b, 120c, and 120d, they will be referred to as power supply unit 120.

[0022] The arm 130 is provided with a first feed line 121a and a second feed line 121b for feeding power to the power feed points 120a, 120b, 120c, and 120d. The first feed line 121a and the second feed line 121b are each branched into two and reach two power feed points diagonally located in the rectangular portion 110. In the example shown in FIG. 4, the first feed line 121a is branched into two at the intersection of the arm portions 130, and extends toward the power feed points 120a and 120c. The second feed line 121b is branched into two and guided to the arm 130, and extends toward the power feed points 120b and 120d. The ends of the feed lines 121a and 121b leading to the power feed point 120 have an open stub structure. Therefore, each of the radiating portions 110a, 110b, 110c, and 110d is fed by an open stub.

[0023] 5, a ground conductor 101 is provided on the rear surface of the rectangular portion 110 (including radiation portions 110a, 110b, 110c, and 110d) and the arm portions 130. The ground conductor is formed of, for example, a copper foil pattern.

[0024] Fig. 6 is an enlarged view of portion A in Fig. 4. In Fig. 6, first power feed line 121a receives a power supply voltage from power receiving port 123a, which is then split into two and extends in opposite directions toward opposing corners of rectangular portion 110. Since second power feed line 121b has already been split into two, it receives a power supply voltage from each of two power receiving ports 123b and extends in opposite directions toward opposing corners of rectangular portion 110.

[0025] 7A and 7B are diagrams showing the configuration of the radiation unit 110d, with FIG. 7A being an enlarged view of portion B1 in FIG. 4 and FIG. 7B being an enlarged view of portion B2 in FIG. 5. The portion B1 in FIG. 4 and the portion B2 in FIG. 5 are the front and back sides of the same location on the radiation unit 110d. Note that while FIGS. 4, 5, and 7 focus on the radiation unit 110d, the other radiation units 110a, 110b, and 110c also have the same configuration. Therefore, in the following description, the radiation units will be referred to as radiating units 110a-d, and the radiation units 110a, 110b, 110c, and 110d will not be distinguished from one another.

[0026] 7(A) and 7(B), radiating portions 110a-d are provided with choke portions 111 and coupling portions 112 in the middle of the wiring. More specifically, radiating portions 110a-d are configured by arranging wiring portions, each consisting of two coupling portions 112 and choke portion 111 sandwiched between them, alternately on the front and back surfaces of rectangular portion 110.

[0027] Figure 8 is a diagram showing the structures of choke section 111 and coupling section 112 of radiating sections 110a-d. Figure 8(A) is a diagram showing the wiring on the front side of rectangular section 110, Figure 8(B) is a diagram showing the wiring on the back side of rectangular section 110, and Figure 8(C) is a diagram showing the circuit configuration realized by choke section 111 and coupling section 112. In Figures 8(A) and (B), to make the relationship between choke section 111 and coupling section 112 easier to understand, the protruding direction of choke section 111 is aligned and the wiring of coupling section 112 is drawn slightly thinner.

[0028] The choke section 111 is formed by bending a wire that is thinner than the other wiring portions into a crank shape. As a result, a choke (L component (inductance)) structure is inserted into the radiation sections 110a-d, as shown in Fig. 8(C). By providing a choke structure in the radiation sections 110a-d, the influence (interference) on the second antenna element 200 is suppressed. However, the VSWR (Voltage Standing Wave Ratio) of the first antenna element 100 itself may be degraded.

[0029] Therefore, coupling portions 112 are provided on both ends of choke portion 111. Coupling portion 112 is configured by arranging the wiring on the front side and the wiring on the back side at corresponding positions. Therefore, in coupling portion 112, the wiring is not directly connected, but a dielectric substrate is interposed. As a result, as shown in FIG. 8(C), a coupling (C component (conductance)) structure is added to radiating portions 110a-d. By providing a coupling structure in addition to a choke structure to radiating portions 110a-d, the VSWR of first antenna element 100 is improved.

[0030] As described above, by providing choke portion 111 and coupling portion 112 in radiating portions 110a-d, the influence (interference) of first antenna element 100 on second antenna element 200 is suppressed, and deterioration of the VSWR of first antenna element 100 is suppressed. Note that the choke length and coupling width are individually designed for each specific antenna device 10 depending on the degree of suppression of interference with second antenna element 200, the VSWR state of first antenna element 100, etc. The choke length is the length (t in FIG. 8A) by which the wiring protrudes from choke portion 111. The coupling width is the width (w in FIG. 8A) of the wiring in coupling portion 112. The positions and number of choke portions in radiating portions 110a-d are individually determined for each specific antenna device 10 depending on the degree of suppression of interference with second antenna element 200, the VSWR state of first antenna element 100, etc.

[0031] Figures 9 and 10 are diagrams illustrating the leg 140 of the first antenna element 100 shown in Figure 3. Figure 9 is a view from the front of Figure 3(B) (the z-direction side shown in Figure 1), and this side will be referred to as the front side hereinafter. Figure 10 is a view from the back of Figure 3(B), and this side will be referred to as the back side hereinafter.

[0032] The leg 140 of the first antenna element 100 is formed of a single dielectric substrate. As shown in FIG. 9 , a first feed line 122a and two ground conductors 101 are provided on the front surface of the leg 140. As shown in FIG. 10 , two second feed lines 122b and a ground conductor 101 are provided on the back surface of the leg 140. As can be seen from FIGS. 9 and 10 , the ground conductor 101 on the front surface of the leg 140 is provided at a position corresponding to the second feed line 122b on the back surface of the leg 140. The ground conductor 101 on the back surface of the leg 140 is provided at a position corresponding to the first feed line 122a on the front surface of the leg 140.

[0033] The first power feed line 122a of the leg portion 140 is connected at its upper end to the first power feed line 121a of the arm portion 130 via a power receiving port 123a (see FIG. 6). The first power feed line 122a is connected at its lower end to a power feed port of the power feed circuit board 150. The two second power feed lines 122b of the leg portion 140 are connected at their upper ends to the two second power feed lines 121b of the arm portion 130 via two power receiving ports 123b (see FIG. 6), respectively. The second power feed lines 122b are connected at their lower ends to power feed ports of the power feed circuit board 150.

[0034] 11 is a diagram showing the feed circuit board 150 of the first antenna element 100. The feed circuit board 150 is attached to the base 300 and connected to the lower end of the leg 140, thereby fixing the first antenna element 100 to the base 300. The feed circuit board 150 has two feed ports (a first feed port 151 and a second feed port 152). The first feed port 151 receives power from one end 151a and supplies it from the other end 151b to the first feed line 122a of the leg 140. The second feed port 152 receives power from one end 152a, distributes it in two, and supplies it from the two ends 152b to the two feed lines 122b of the leg, respectively.

[0035] As described above, the first antenna element 100 has the following two power systems. One system runs from the first feed port 151 through the first feed line 122a, is split into two at the first feed line 121a, and reaches the two feed units 120a and 120c. This system will be referred to as the first system below. The other system runs from the second feed port 152 through two second feed lines 122b and two second feed lines 121b to reach the two feed units 120b and 120d. This system will be referred to as the second system below. With the above configuration, the first antenna element 100 simultaneously operates the two diagonally positioned feed units 120a and 120c that belong to each system. Moreover, first antenna element 100 switches between these two power systems, thereby individually operating the pair of two power feeding sections 120a, 120c belonging to each system.

[0036] 2 and 4, the relationship between power feeding and polarization in first antenna element 100 will be described. The positions of each corner and each side of the rectangular shape showing first antenna element 100 in FIG. 2 correspond to the positions of each of feed portions 120a-120d and each of radiating portions 110a-110d shown in FIG. 4. That is, the upper left corner of the rectangle in FIG. 2 corresponds to feed portion 120a, the upper right corner corresponds to feed portion 120b, the lower right corner corresponds to feed portion 120c, and the lower left corner corresponds to feed portion 120d. Furthermore, the upper side of the rectangle in FIG. 2 corresponds to radiating portion 110a, the right side corresponds to radiating portion 110b, the lower side corresponds to radiating portion 110c, and the left side corresponds to radiating portion 110d.

[0037] 2 and 4, when the first system is activated, power is fed from feeder 120a and feeder 120c to four radiators 110a-110d via first feed line 121a. A -45° polarized wave is generated by the four radiators 110a-110d that have received the power. When the second system is activated, power is fed from feeder 120b and feeder 120d to four radiators 110a-110d via second feed line 121b. A +45° polarized wave is generated by the four radiators 110a-110d that have received the power.

[0038] Referring again to Figure 3, the size of the first antenna element 100 is determined according to the corresponding frequency, etc. Here, as an example, the design center frequency fc is set to 0.756 GHz. In this case, the design dimensions of the first antenna element 100 are, for example, the length of one side of the rectangular portion 110 being 146 mm ≒ 0.37 λc, and the height relative to the base 300 (the length of the leg portion 140) being approximately 90 mm ≒ 0.27 λc. Furthermore, since the rectangular portion 110 is approximately square, the total length of the two arms 130 connecting the diagonal corners is, for example, approximately 190 mm.

[0039] 19 is a diagram showing an example of the configuration of a cross dipole element. The size of a cross dipole element 400 having similar performance to the above-described first antenna element 100 is, for example, the length of one of the intersecting arms (the total length of the two arms extending in opposite directions from the intersection point) of about 206 mm. The height of the intersecting arms relative to the base 300 is, for example, about 81 mm. Furthermore, the length of one side of a square formed with the intersecting arms as its diagonal (in other words, the square as the outline of the cross dipole element 400) is, for example, about 177 mm.

[0040] Comparing the length of one side of the rectangular portion 110 of the first antenna element 100 (146 mm) with the length of one side of the square external shape of the cross dipole element 400 (177 mm), the former is shorter, at approximately 82% of the latter. Therefore, the area occupied by the rectangular portion 110 is approximately 68% of the area occupied by the square external shape of the cross dipole element 400, achieving miniaturization. In other words, the length of one side of the rectangular portion 110 of the first antenna element 100 is approximately 18% shorter than the length of one side of the external shape of the cross dipole element, and the area ratio is approximately 32% smaller.

[0041] <Configuration of the Antenna Device 10 and Arrangement of the Second Antenna Element 200> In the configuration example shown in FIG. 3, the base 300 to which the first antenna element 100 is attached is rectangular with long sides of 300 mm and single sides of 225 mm. The long sides of the base 300 have raised sides with a height of 30 mm. Although not shown in FIG. 3, the second antenna elements 200 are attached to the base 300 in two rows of three each, as shown in FIG. 1. In FIG. 3, the base 300 has rectangular holes formed on both the left and right sides of the feeder circuit board 150 of the first antenna element 100. The second antenna elements 200 are attached to these two rows, totaling six holes. The spacing between the second antenna elements 200 in one row is, for example, 100 mm. The spacing between the two rows of second antenna elements 200 is, for example, 112.5 mm.

[0042] <Influence of the First Antenna Element 100 on the Second Antenna Element 200> Next, the influence of the first antenna element 100 on the second antenna element 200 will be described. As shown in FIG. 1, the antenna device 10 is provided with a first antenna element 100 corresponding to a low-band frequency band and a second antenna element 200 corresponding to a middle-band frequency band. In the following description, the first antenna element 100 may be referred to as a low-band element, and the second antenna element 200 may be referred to as a middle-band element. In such an antenna device 10, the influence of the first antenna element 100 (low-band element) on the radiation pattern of the second antenna element 200 (middle-band element) becomes an issue. Below, the influence of the first antenna element 100 on the radiation pattern of the second antenna element 200 will be described.

[0043] Fig. 12 is a diagram showing an example of the radiation pattern of the second antenna element 200. Fig. 12(A) is a diagram showing the radiation pattern when the first antenna element 100 is not present, Fig. 12(B) is a diagram showing the radiation pattern when the first antenna element 100 is present, and Fig. 12(C) is a graph showing the amount of change (difference) between the radiation pattern of Fig. 12(A) and the radiation pattern of Fig. 12(B). As shown in Fig. 1, the second antenna elements 200 have an array structure with two rows of three elements each. Figs. 12(A) and (B) show the radiation pattern in the horizontal plane (also called the array pattern) of one row of the second antenna elements 200.

[0044] Comparing Figures 12(A) and (B), the radiation patterns are similar regardless of whether the first antenna element 100 is present or not. Referring to Figure 12(C), the loss is within the range of -2dB to 3dB between -50° and +50°. Therefore, it can be seen that the radiation pattern when the first antenna element 100 is present, as shown in Figure 12(B), is not significantly degraded compared to the radiation pattern when the first antenna element 100 is not present, as shown in Figure 12(A).

[0045] FIG. 13 illustrates the influence of a low-band element on the radiation pattern of a middle-band element. FIG. 13(A) illustrates the amount of pattern change when the first antenna element 100 is used as the low-band element, and FIG. 13(B) illustrates the amount of pattern change when a cross dipole element is used as the low-band element. FIGS. 13(A) and 13(B) illustrate simulation results of the amount of change in the radiation pattern of the middle-band element (second antenna element 200) at +45° polarization with and without the low-band element for multiple frequencies. The amount of change in the radiation pattern is determined using the method described with reference to FIGS. 12(A) to 12(C). The multiple frequencies are six in this example: 1.7 GHz, 1.9 GHz, 2.1 GHz, 2.3 GHz, 2.5 GHz, and 2.7 GHz. Therefore, FIGS. 13(A) and 13(B) each illustrate graphs of the amount of change in the radiation pattern for the six frequencies, obtained in a manner similar to that of FIG. 12(C).

[0046] Comparing the graph in FIG. 13(A), which uses the first antenna element 100 as the low-band element, with the graph in FIG. 13(B), which uses a cross dipole element as the low-band element, the graphs are similar at all frequencies. The maximum pattern change in both cases is approximately 3 dB. Therefore, the degree of interference with the radiation pattern of the middle-band element in the first antenna element 100 can be said to be similar to that of a cross dipole element. As described with reference to FIGS. 3 and 19, the first antenna element 100 is approximately 32% smaller in area than the cross dipole element. In other words, the first antenna element 100 can be used as a low-band element with low interference characteristics similar to those of a cross dipole element but smaller in size than a cross dipole element.

[0047] FIG. 14 is a diagram showing the VSWR of the antenna elements in the antenna device 10. FIG. 14(A) shows the VSWR of the first antenna element 100, and FIG. 14(B) shows the VSWR of the second antenna element 200. In FIGS. 14(A) and 14(B), the solid line is a graph showing the measured VSWR value for +45° polarization, and the dashed line is a graph showing the measured VSWR value for −45° polarization. The desired low-band frequency band is set to 0.617 GHz to 0.894 GHz. Referring to FIG. 14(A), the VSWR of the first antenna element 100 in this desired frequency band is 1.7 or less. The desired middle-band frequency band is set to 1.7 GHz to 2.7 GHz. Referring to FIG. 14(B), the VSWR of the second antenna element 200 in this desired frequency band is 1.9 or less. Therefore, both the first antenna element 100 and the second antenna element 200 exhibit good characteristics.

[0048] Fig. 15 is a diagram showing radiation patterns in the horizontal plane for a pair of second antenna elements 200 when there is a first antenna element 100. Fig. 15(A) is a diagram showing a radiation pattern at a frequency of 1.7 GHz, Fig. 15(B) is a diagram showing a radiation pattern at a frequency of 1.9 GHz, Fig. 15(C) is a diagram showing a radiation pattern at a frequency of 2.1 GHz, Fig. 15(D) is a diagram showing a radiation pattern at a frequency of 2.3 GHz, Fig. 15(E) is a diagram showing a radiation pattern at a frequency of 2.5 GHz, and Fig. 15(F) is a diagram showing a radiation pattern at a frequency of 2.7 GHz.

[0049] Fig. 16 is a diagram showing radiation patterns in the horizontal plane for a set of second antenna elements 200 when there is no second antenna element 200. As with Fig. 15, Fig. 16(A) is a diagram showing a radiation pattern at a frequency of 1.7 GHz, Fig. 16(B) is a diagram showing a radiation pattern at a frequency of 1.9 GHz, Fig. 16(C) is a diagram showing a radiation pattern at a frequency of 2.1 GHz, Fig. 16(D) is a diagram showing a radiation pattern at a frequency of 2.3 GHz, Fig. 16(E) is a diagram showing a radiation pattern at a frequency of 2.5 GHz, and Fig. 16(F) is a diagram showing a radiation pattern at a frequency of 2.7 GHz.

[0050] Figures 15(A) to (F) and Figures 16(A) to (F) show radiation patterns in the horizontal plane for +45° polarization. Comparing Figures 15(A) to (F) with Figures 16(A) to (F), it is clear that similar radiation patterns are obtained in both. This shows that the influence of the first antenna element 100 on the radiation pattern of the second antenna element 200 is well suppressed.

[0051] 17A and 17B show the effect of the low-band element on the radiation pattern of the middle-band element through simulation. FIG. 17A shows the pattern change amount in +45° polarization, and FIG. 17B shows the pattern change amount in −45° polarization. FIGS. 17A and 17B show the results of a simulation of the radiation pattern change amount of the second antenna element 200 for multiple frequencies. The radiation pattern change amount is determined by the method described with reference to FIGS. 12A to 12C. The multiple frequencies here are six types, 1.7 GHz, 1.9 GHz, 2.1 GHz, 2.3 GHz, 2.5 GHz, and 2.7 GHz, as in the example shown in FIG. 13. Therefore, FIGS. 17A and 17B each show graphs of the radiation pattern change amount for the six types of frequencies, obtained in the same manner as the graph of FIG. 12C.

[0052] FIG. 18 shows the influence of the low-band element on the radiation pattern of the middle-band element using actual measurements. FIG. 18(A) shows the pattern change amount in +45° polarization, and FIG. 18(B) shows the pattern change amount in −45° polarization. FIGS. 18(A) and 18(B) show the actual measured values ​​of the radiation pattern change amount of the second antenna element 200 for multiple frequencies. The radiation pattern change amount is determined by the method described with reference to FIGS. 12(A) to 12(C). The multiple frequencies here are six types, 1.7 GHz, 1.9 GHz, 2.1 GHz, 2.3 GHz, 2.5 GHz, and 2.7 GHz, as in the example shown in FIG. 13. Therefore, FIGS. 18(A) and 18(B) each show graphs of the radiation pattern change amount for the six types of frequencies, obtained in the same manner as the graph of FIG. 12(C).

[0053] Comparing Figure 17(A) with Figure 18(A), and Figure 17(B) with Figure 18(B), the two graphs are similar. This confirms that the actual measurements have the same low interference effect as the simulation.

[0054] Although the embodiments of the present invention have been described above, the technical scope of the present invention is not limited to the above-described embodiments. Various modifications and alternative configurations that do not depart from the scope of the technical idea of ​​the present invention are included in the present invention. [Explanation of symbols]

[0055] 10...antenna device, 100...first antenna element, 110...rectangular portion, 110a to 110d...radiating portion, 111...choke portion, 112...coupling portion, 120...power supply portion, 121a, 122a...first power supply line, 121b, 122b...second power supply line, 130...arm portion, 140...leg portion, 150...power supply circuit board, 151...first power supply port, 152...second power supply port

Claims

1. A dipole antenna, Four radiating parts arranged in a rectangular shape; four power supply units arranged at respective corners of a rectangle formed by the four radiating units, and supplying power to two of the radiating units that sandwich each corner; a pair of power supply units, each of which is disposed at two opposite corners and belongs to one power system, supplying a voltage to the four radiating units to generate one of two orthogonal polarized waves; The other of the two orthogonal polarized waves is supported by a power supply voltage to the four radiating units from another set of power supply units that are arranged at two opposing corners different from the two corners and belong to another power system different from the power system. A dipole antenna characterized by:

2. 2. The dipole antenna according to claim 1, wherein each of the four radiating portions has a choke structure in which a portion of a conductor wiring is bent.

3. 3. The dipole antenna according to claim 2, wherein each of the four radiating portions has a coupling structure in which the width of the wiring is increased on both ends of the choke structure.

4. 2. The dipole antenna according to claim 1, wherein two feed lines are each split into two and extend from a center of a rectangle formed by the four radiating portions toward two sets of opposing corners of the rectangle, and power is supplied from each of the four feed portions to two of the radiating portions on either side of the feed portion.

5. 5. The dipole antenna according to claim 4, wherein the power supply portion has an open stub structure in which a tip of the power supply line is open and power is supplied to the radiation portion through the open portion.

6. a leg portion rising from a power supply circuit board having a power supply port; four arms extending in all directions from the upper ends of the legs; a rectangular portion connecting the ends of the four arms, the two power supply lines are wired to the leg portions and the arm portions, The four radiation portions are formed in the rectangular portion.

5. The dipole antenna according to claim 4,

7. The leg portion is formed of a single substrate, 7. The dipole antenna according to claim 6, wherein one of the two feeder lines is split into two at the lower end of the leg, and the other is split into two at the upper end of the leg.

8. a first antenna element configured by a dipole antenna according to any one of claims 1 to 7; a second antenna element corresponding to a different frequency band from the first antenna element; a reflector to which the first antenna element and the second antenna element are attached; An antenna device comprising:

9. 9. The antenna device according to claim 8, wherein the first antenna element corresponds to a lower frequency band than the second antenna element.

10. 9. The antenna device according to claim 8, wherein the second antenna element forms an array antenna with a plurality of antenna elements arranged on the reflector.

11. 9. The antenna device according to claim 8, wherein the second antenna element is provided at a position closer to the reflector than the first antenna element.

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