Dipole antenna and antenna equipment

Abstract

The present invention provides an antenna element that can be miniaturized while suppressing the degradation of frequency characteristics caused by interference between antennas with different frequency bands. [Solution] A dipole antenna comprising four rectangularly arranged radiating sections 110a to 110d, and four feeding sections 120a to 120d positioned at each corner of the rectangle formed by the four radiating sections 110a to 110d, feeding power to two radiating sections 110a to 110d flanking each corner, wherein the feeding voltage from one pair of feeding sections 120a to 120d positioned at two opposing corners corresponds to one of two orthogonal polarization directions, and the feeding voltage from another pair of feeding sections 120a to 120d positioned at two opposing corners different from the two corners corresponds to the other of the two orthogonal polarization directions.

Description

Technical Field

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

Background Art

[0002] In an antenna device used for a base station or the like, in order to support a wide frequency band, several types of antenna elements corresponding to different frequency bands are combined and configured.

[0003] Patent Document 1 discloses a multi-band circular polarization 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

Summary of the Invention

Problems to be Solved by the Invention

[0005] An antenna device is required to be smaller from the viewpoints of reducing installation work and reducing the influence of wind or the like after installation. In an antenna device combining a plurality of antennas corresponding to different frequency bands, it is required to realize further miniaturization while reducing interference between the antennas.

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

[0007] The present invention, which achieves the above objective, It is a dipole antenna, Four radial sections arranged in a rectangular shape, It comprises four power supply units, each positioned at one corner of a rectangle formed by four radiating units, and supplying power to the two radiating units flanking each corner. The power supply voltage from a pair of power supply units located at two opposing corners to the four radiating units corresponds to one of the two orthogonal polarization directions. This is a dipole antenna that uses the feed voltage from another set of feed points located at two opposing corners, different from the two corners, to supply voltages to four radiating elements, corresponding to the polarization of one of two orthogonal directions. More specifically, each of the four radial sections may have a choke structure in which a portion of the conductor wiring is bent. More specifically, each of the four radial sections may be configured to have a coupling structure with a wider wiring width at both ends of the choke structure. Alternatively, the two power supply lines may each be divided into two, extending from the center of the rectangle formed by the four radiating sections toward two pairs of opposing corners in the rectangle, and supplying power from each of the four power supply sections to the two radiating sections flanking each power supply section. More specifically, in the power supply section, the power supply line may be configured as an open stub. Furthermore, the legs that rise from the power supply circuit board having a power supply port, Four arms extend outwards from the upper end of the legs, It comprises a rectangular section connecting the ends of each of the four arms, Two separate power supply lines are wired to the legs and arms. Alternatively, the rectangular section may be configured with four radial sections. Furthermore, the legs are made of a single circuit board. Alternatively, one of the two power supply lines may be split into two at the lower end of the leg, and the other line may be split into two at the upper end of the leg. Furthermore, the present invention, which achieves the above objectives, The first antenna element is composed of the dipole antenna described above, 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, This is an antenna device equipped with [a specific feature / feature]. Here, the first antenna element may be configured to correspond to a lower frequency band than the second antenna element. Alternatively, the second antenna element may be configured to form an array antenna consisting of multiple antenna elements arranged on a reflector. Furthermore, the second antenna element may be positioned closer to the reflector than the first antenna element. [Effects of the Invention]

[0008] According to the present invention, an antenna device and antenna elements constituting this antenna device, which combine multiple antennas corresponding to different frequency bands, can be miniaturized while suppressing the degradation of frequency characteristics due to interference between antennas of different frequency bands. [Brief explanation of the drawing]

[0009] [Figure 1] This figure shows the configuration of the antenna device according to this embodiment. [Figure 2] This is a diagram illustrating the model and operating principle of the first antenna element. [Figure 3] Figure 3(A) shows the external shape and arrangement of the first antenna element, with Figure 3(B) being a view of the antenna device shown in Figure 1 from the x-direction, and Figure 3(B) being a view of the antenna device shown in Figure 1 from the z-direction. [Figure 4] It is a view in which the rectangular portion and the arm portion of the first antenna element shown in FIG. 3 are extracted, and it is a view seen from the front (the x-direction side shown in FIG. 1) of FIG. 3(A). [Figure 5] It is a view in which the rectangular portion and the arm portion of the first antenna element shown in FIG. 3 are extracted, and it is a view seen from the back side of FIG. 3(A). [Figure 6] It is an enlarged view of part A in FIG. 4. [Figure 7] It is a view showing the configuration of the radiation part. [Figure 8] It is a view showing the structure of the choke part and the coupling part of the radiation part. FIG. 8(A) is a view showing the wiring on the front side of the rectangular part, FIG. 8(B) is a view showing the wiring on the back side of the rectangular part, and FIG. 8(C) is a view showing the circuit configuration realized by the choke part and the coupling part. [Figure 9] It is a view in which the leg portion of the first antenna element shown in FIG. 3 is extracted, and it is a view seen from the front (the z-direction side shown in FIG. 1) of FIG. 3(B). [Figure 10] It is a view in which the leg portion of the first antenna element shown in FIG. 3 is extracted, and it is a view seen from the back side of FIG. 3(B). [Figure 11] It is a view showing the power supply circuit board of the first antenna element. [Figure 12] It is a view showing an example of the radiation pattern of the second antenna element. FIG. 12(A) is a view showing the radiation pattern when the first antenna element is not present, FIG. 12(B) is a view showing the radiation pattern when the first antenna element is present, and FIG. 12(C) is a graph showing the amount of change (difference) between the pattern in FIG. 12(A) and the pattern in FIG. 12(B). [Figure 13] It is a view showing the influence of the low band element on the radiation pattern of the middle band element. FIG. 13(A) is a view showing the amount of pattern change when the first antenna element is used as the low band element, and FIG. 13(B) is a view showing the amount of pattern change when the cross dipole element is used as the low band element. [Figure 14] It is a view showing the VSWR of the antenna element in the antenna device. FIG. 14(A) is a view showing the VSWR of the first antenna element, and FIG. 14(B) is a view showing the VSWR of the second antenna element. [Figure 15] Figure 15(A) shows the radiation pattern in the horizontal plane for a set of second antenna elements with a first antenna element. Figure 15(B) shows the radiation pattern at a frequency of 1.9 GHz, Figure 15(C) shows the radiation pattern at a frequency of 2.1 GHz, Figure 15(D) shows the radiation pattern at a frequency of 2.3 GHz, Figure 15(E) shows the radiation pattern at a frequency of 2.5 GHz, and Figure 15(F) shows the radiation pattern at a frequency of 2.7 GHz. [Figure 16] Figure 16(A) shows the radiation pattern in the horizontal plane for a set of second antenna elements when the second antenna element is absent. Figure 16(B) shows the radiation pattern at a frequency of 1.9 GHz, Figure 16(C) shows the radiation pattern at a frequency of 2.1 GHz, Figure 16(D) shows the radiation pattern at a frequency of 2.3 GHz, Figure 16(E) shows the radiation pattern at a frequency of 2.5 GHz, and Figure 16(F) shows the radiation pattern at a frequency of 2.7 GHz. [Figure 17] These figures show the effect of low-band elements on the radiation pattern of middle-band elements, as determined by simulation. Figure 17(A) shows the pattern change at +45° polarization, and Figure 17(B) shows the pattern change at -45° polarization. [Figure 18] These figures show the effect of low-band elements on the radiation pattern of middle-band elements based on measured values. Figure 18(A) shows the pattern change at +45° polarization, and Figure 18(B) shows the pattern change at -45° polarization. [Figure 19] This figure shows an example of a cross-dipole element configuration. [Modes for carrying out the invention]

[0010] Embodiments of the present invention will be described in detail below with reference to the attached drawings.

[0011] <Antenna System Configuration> Figure 1 shows the configuration of the antenna device according to this embodiment. The antenna device 10 shown in Figure 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. Hereafter, when the first antenna element 100 and the second antenna element 200 are not distinguished, 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 and 200 are arranged. Although not shown in the figure, a cover is attached to the antenna device 10 so as to cover the arrangement of antenna elements 100 and 200.

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

[0013] In the example shown in Figure 1, one first antenna element 100 and six second antenna elements 200 are provided on the base 300. The second antenna elements 200 are arranged in two rows of three on each side of the first antenna element 100. In Figure 1, the six second antenna elements 200 are individually labeled with subscripts a to f. When distinguishing between individual second antenna elements 200, these subscripts a to f may be added, resulting in labels such 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 positioned higher than the second antenna element 200. In other words, the first antenna element 100 is further from the reflector of the base 300 than the second antenna element 200.

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

[0016] <Operating principle of the first antenna element 100> Figure 2 illustrates the model and operating principle of the first antenna element 100. For comparison, Figure 2 also includes a diagram showing the model and operating principle of a cross dipole element, which is a common configuration of 2MIMO antenna elements. As shown in Figure 2, the cross dipole element is constructed by combining two orthogonal dipole elements, as shown in the element model. Then, two orthogonal polarization directions (here, -45° and +45°) operate independently in the two dipole elements. In the example of the operating principle shown in Figure 2, it is shown that a -45° polarization is generated in the dipole element (a), which is shown sloping upwards to the right, and a +45° polarization is generated in the dipole element (b), which is shown sloping downwards to the right.

[0017] On the other hand, the first antenna element 100 is constructed by combining four radiating sections in a rectangular shape, as shown in the element model. In this first antenna element 100, the feed points are located at the four corners. By applying a feed voltage from feed points located at two diagonally opposite corners of the rectangle formed by the four radiating sections, two-directional polarization (-45° and +45°) operates in the four radiating sections. In the example of the operating principle shown in Figure 2, it is shown that a -45° polarization is generated when a feed voltage is applied from the upper left and lower right feed points, and a +45° polarization is generated when a feed voltage is applied from the upper right and lower left feed points.

[0018] <Configuration of the first antenna element 100> Figure 3 shows the external shape and arrangement of the first antenna element 100. Figure 3(A) is a view of the antenna device 10 shown in Figure 1 from the x-direction, and Figure 3(B) is a view of the antenna device 10 shown in Figure 1 from the z-direction. However, the second antenna element 200 is omitted from Figures 3(A) and (B).

[0019] The first antenna element 100 includes a power supply circuit board 150 attached to a base 300, leg portions 140 rising vertically (in the x-direction in Figure 1) from the power supply circuit board 150, arm portions 130 extending in all directions from the upper ends of the leg portions 140, and a rectangular portion 110 connecting the ends of the arm portions 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, by a copper foil pattern.

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

[0021] As shown in Figure 4, the rectangular section 110 is composed of four radiating sections 110a, 110b, 110c, and 110d. Power supply sections 120a, 120b, 120c, and 120d are provided at the four corners of the rectangular section 110. In the example shown in Figure 4, the power supply section 120a is provided at the corner between radiating section 110d and radiating section 110a. The power supply section 120b is provided at the corner between radiating section 110a and radiating section 110b. The power supply section 120c is provided at the corner between radiating section 110b and radiating section 110c. The power supply section 120d is provided at the corner between radiating section 110c and radiating section 110d. Hereafter, if it is not necessary to distinguish between each power supply unit 120a, 120b, 120c, and 120d, they will be referred to as power supply unit 120.

[0022] The arm section 130 is provided with a first power supply line 121a and a second power supply line 121b for supplying power to power supply sections 120a, 120b, 120c, and 120d. Both the first power supply line 121a and the second power supply line 121b are split into two, reaching two diagonally opposite power supply sections in the rectangular section 110. In the example shown in Figure 4, the first power supply line 121a is split into two at the point where the arm sections 130 intersect, and extends toward power supply section 120a and power supply section 120c. The second power supply line 121b is led to the arm section 130 in a split state and extends toward power supply section 120b and power supply section 120d. The ends of each power supply line 121a and 121b that reach the power supply section 120 have an open stub structure. Therefore, open stub power is supplied to each of the radiating sections 110a, 110b, 110c, and 110d.

[0023] As shown in Figure 5, a ground conductor 101 is formed on the back surface of the rectangular portion 110 (including the radial portions 110a, 110b, 110c, and 110d) and the arm portion 130. The ground conductor is formed, for example, by a copper foil pattern.

[0024] Figure 6 is an enlarged view of section A in Figure 4. In Figure 6, the first power supply line 121a receives the power supply voltage from the power receiving port 123a, is divided into two, and extends in opposite directions toward the opposing corners of the rectangular section 110. The second power supply line 121b has already been divided into two, so it receives the power supply voltage from each of the two power receiving ports 123b and extends in opposite directions toward the opposing corners of the rectangular section 110.

[0025] Figure 7 shows the configuration of the radiating section 110d. Figure 7(A) is an enlarged view of section B1 in Figure 4, and Figure 7(B) is an enlarged view of section B2 in Figure 5. Section B1 in Figure 4 and section B2 in Figure 5 are the front and back sides of the same location on the radiating section 110d. Although Figures 4, 5, and 7 focus on the radiating section 110d, the other radiating sections 110a, 110b, and 110c have a similar configuration. Therefore, in the following explanation, we will refer to them as radiating sections 110a-d and will not distinguish between each of the radiating sections 110a, 110b, 110c, and 110d.

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

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

[0028] The choke section 111 is constructed by bending thinner wiring than other wiring sections into a crank shape. As a result, a choke (L component (inductance)) structure is inserted into the radiating sections 110a-d, as shown in Figure 8(C). By providing the choke structure in the radiating 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 deteriorate.

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

[0030] As described above, by providing choke sections 111 and coupling sections 112 in the radiating sections 110a-d, the influence (interference) of the first antenna element 100 on the second antenna element 200 is suppressed, and the deterioration of the VSWR of the first antenna element 100 is suppressed. The choke length and coupling width are individually designed for each specific antenna device 10 according to the degree of interference suppression on the second antenna element 200, the VSWR state of the first antenna element 100, etc. The choke length is the length of the wiring that protrudes in the choke section 111 (t in Figure 8(A)). The coupling width is the width of the wiring in the coupling section 112 (w in Figure 8(A)). Furthermore, the position and number of choke sections in the radiating sections 110a-d are individually determined for each specific antenna device 10 according to the degree of interference suppression on the second antenna element 200, the VSWR state of the first antenna element 100, etc.

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

[0032] The legs 140 of the first antenna element 100 are made of a single dielectric substrate. As shown in Figure 9, the surface of the legs 140 is provided with one first feed line 122a and two ground conductors 101. Also, as shown in Figure 10, the back surface of the legs 140 is provided with two second feed lines 122b and one ground conductor 101. As can be seen by referring to Figures 9 and 10, the ground conductors 101 on the surface of the legs 140 are located at positions corresponding to the second feed lines 122b on the back surface of the legs 140. Also, the ground conductors 101 on the back surface of the legs 140 are located at positions corresponding to the first feed line 122a on the surface of the legs 140.

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

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

[0035] As described above, the first antenna element 100 has the following two power systems. One system goes from the first feed port 151 through the first feed line 122a, is split into two at the first feed line 121a, and goes to two feed points 120a and 120c. Hereafter, this system will be referred to as the first system. The other system is split into two at the second feed port 152, and goes to two feed points 120b and 120d through two second feed lines 122b and two second feed lines 121b. Hereafter, this system will be referred to as the second system. With the above configuration, the first antenna element 100 operates the two diagonally positioned feed points 120a and 120c belonging to each system simultaneously. Furthermore, the first antenna element 100 switches between these two power systems, thereby individually operating the two sets of feed points 120a and 120c belonging to each system.

[0036] Referring again to Figures 2 and 4, the relationship between feeding and polarization in the first antenna element 100 will be explained. The positions of each corner and side in the rectangular figure showing the first antenna element 100 in Figure 2 correspond to the positions of each feeding point 120a to 120d and each radiating point 110a to 110d shown in Figure 4. That is, the upper left corner of the rectangle in Figure 2 corresponds to the feeding point 120a, the upper right corner corresponds to the feeding point 120b, the lower right corner corresponds to the feeding point 120c, and the lower left corner corresponds to the feeding point 120d. Also, the top side of the rectangle in Figure 2 corresponds to the radiating point 110a, the right side corresponds to the radiating point 110b, the bottom side corresponds to the radiating point 110c, and the left side corresponds to the radiating point 110d.

[0037] As can be seen by referring to Figures 2 and 4, when the first system is activated, power is supplied to the four radiating units 110a to 110d from the power supply units 120a and 120c via the first power supply line 121a. Then, the four radiating units 110a to 110d that receive power generate a -45° polarization. When the second system is activated, power is supplied to the four radiating units 110a to 110d from the power supply units 120b and 120d via the second power supply line 121b. Then, the four radiating units 110a to 110d that receive power generate a +45° polarization.

[0038] Refer to Figure 3 again. 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 = 0.756 GHz is assumed. In this case, the design dimensions of the first antenna element 100 are, for example, that the length of one side of the rectangular section 110 is 146 mm ≈ 0.37 λc, and the height relative to the base 300 (length of the leg section 140) is 90 mm ≈ 0.27 λc. Also, since the rectangular section 110 is roughly square, the sum of the lengths of the two arms 130 connecting the diagonals is, for example, about 190 mm.

[0039] Figure 19 shows an example of a cross dipole element configuration. The size of the cross dipole element 400, which has performance comparable to the first antenna element 100 described above, is such that the length of one of the intersecting arms (the sum of the lengths of the two arms extending in opposite directions from the intersection) is approximately 206 mm. The height of the intersecting arms relative to the base 300 is approximately 81 mm. The length of one side of the square (in other words, the square as the outer shape of the cross dipole element 400) assumed to have the intersecting arms as diagonals is approximately 177 mm.

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

[0041] <Configuration of antenna device 10, arrangement of second antenna element 200> In the configuration example shown in Figure 3, the base 300 to which the first antenna element 100 is attached is a rectangle with a long side of 300 mm and a short side of 225 mm. A raised edge with a height of 30 mm is formed on the long side of the base 300. Although not shown in Figure 3, the second antenna elements 200 are attached to the base 300 in two rows of three, as shown in Figure 1. In Figure 3, rectangular holes are provided on both the left and right sides of the power supply circuit board 150 of the first antenna element 100 on the base 300. 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 rows of second antenna elements 200 in two rows is, for example, 112.5 mm.

[0042] <Influence of the first antenna element 100 on the second antenna element 200> Next, we will explain the influence of the first antenna element 100 on the second antenna element 200. As shown in Figure 1, the antenna device 10 is equipped with a first antenna element 100 corresponding to the low-band frequency range and a second antenna element 200 corresponding to the middle-band frequency range. In the following explanation, the first antenna element 100 may be referred to as the low-band element, and the second antenna element 200 as the 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 a problem. Below, we will explain the influence of the first antenna element 100 on the radiation pattern of the second antenna element 200.

[0043] Figure 12 shows an example of the radiation pattern of the second antenna element 200. Figure 12(A) shows the radiation pattern when the first antenna element 100 is absent, Figure 12(B) shows the radiation pattern when the first antenna element 100 is present, and Figure 12(C) is a graph showing the change (difference) between the radiation pattern in Figure 12(A) and the radiation pattern in Figure 12(B). As shown in Figure 1, the second antenna element 200 has an array structure with three elements in two rows. Figures 12(A) and (B) show the horizontal plane radiation pattern (also called the array pattern) of one row of the second antenna element 200 (array).

[0044] Comparing Figures 12(A) and (B), the radiation patterns are similar regardless of the presence or absence of the first antenna element 100. Referring to Figure 12(C), the radiation level falls between -2dB and 3dB between -50° and +50°. Therefore, it can be seen that the radiation pattern with the first antenna element 100, shown in Figure 12(B), is not significantly degraded compared to the radiation pattern without the first antenna element 100, shown in Figure 12(A).

[0045] Figure 13 shows the effect of a low-band element on the radiation pattern of a middle-band element. Figure 13(A) shows the pattern change when the first antenna element 100 is used as the low-band element, and Figure 13(B) shows the pattern change when a cross dipole element is used as the low-band element. Figures 13(A) and (B) show the results of simulations of the 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 change in the radiation pattern is determined by the method described with reference to Figures 12(A) to (C). The multiple frequencies are set to six types here: 1.7GHz, 1.9GHz, 2.1GHz, 2.3GHz, 2.5GHz, and 2.7GHz. Therefore, Figures 13(A) and (B) show graphs of the change in the radiation pattern obtained in the same way as the graph in Figure 12(C) for the above six types of frequencies.

[0046] Comparing the graph in Figure 13(A), which uses the first antenna element 100 as a low-band element, with the graph in Figure 13(B), which uses a cross dipole element as a low-band element, the graphs are similar at all frequencies. Furthermore, the pattern change in both cases is approximately 3 dB at its maximum. Therefore, it can be said that the degree of interference with the radiation pattern of the middle-band element is about the same for the first antenna element 100 as for the cross dipole element. As explained with reference to Figures 3 and 19, the first antenna element 100 is about 32% smaller in area than the cross dipole element. In other words, the first antenna element 100 has low interferometry comparable to that of a cross dipole element, and can be used as a low-band element that is smaller in size than a cross dipole element.

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

[0048] Figure 15 shows the horizontal radiation pattern for a pair of second antenna elements 200 with a first antenna element 100. Figure 15(A) shows the radiation pattern at a frequency of 1.7 GHz, Figure 15(B) shows the radiation pattern at a frequency of 1.9 GHz, Figure 15(C) shows the radiation pattern at a frequency of 2.1 GHz, Figure 15(D) shows the radiation pattern at a frequency of 2.3 GHz, Figure 15(E) shows the radiation pattern at a frequency of 2.5 GHz, and Figure 15(F) shows the radiation pattern at a frequency of 2.7 GHz.

[0049] Figure 16 shows the horizontal radiation pattern for the set of second antenna elements 200 when the second antenna element 200 is absent. Similar to Figure 15, Figure 16(A) shows the radiation pattern at a frequency of 1.7 GHz, Figure 16(B) shows the radiation pattern at a frequency of 1.9 GHz, Figure 16(C) shows the radiation pattern at a frequency of 2.1 GHz, Figure 16(D) shows the radiation pattern at a frequency of 2.3 GHz, Figure 16(E) shows the radiation pattern at a frequency of 2.5 GHz, and Figure 16(F) shows the radiation pattern at a frequency of 2.7 GHz.

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

[0051] Figure 17 shows the effect of a low-band element on the radiation pattern of a middle-band element, as determined by simulation. Figure 17(A) shows the pattern change at +45° polarization, and Figure 17(B) shows the pattern change at -45° polarization. Figures 17(A) and (B) show the results of simulations of the change in the radiation pattern of the second antenna element 200 for multiple frequencies. The change in the radiation pattern is determined by the method described with reference to Figures 12(A) to (C). The multiple frequencies are six types: 1.7GHz, 1.9GHz, 2.1GHz, 2.3GHz, 2.5GHz, and 2.7GHz, as in the example shown in Figure 13. Therefore, Figures 17(A) and (B) show graphs of the change in the radiation pattern obtained in the same way as the graph in Figure 12(C) for the above six frequencies, respectively.

[0052] Figure 18 shows the effect of the low-band element on the radiation pattern of the middle-band element, based on measured values. Figure 18(A) shows the pattern change at +45° polarization, and Figure 18(B) shows the pattern change at -45° polarization. Figures 18(A) and (B) show the measured values ​​of the change in the radiation pattern of the second antenna element 200 for multiple frequencies. The change in the radiation pattern is determined by the method described with reference to Figures 12(A) to (C). The multiple frequencies are six types: 1.7GHz, 1.9GHz, 2.1GHz, 2.3GHz, 2.5GHz, and 2.7GHz, as in the example shown in Figure 13. Therefore, Figures 18(A) and (B) show graphs of the change in the radiation pattern obtained in the same way as the graph in Figure 12(C) for the above six frequencies, respectively.

[0053] Comparing Figure 17(A) with Figure 18(A), and Figure 17(B) with Figure 18(B), the two graphs are similar. This indicates that the low interference effect in the measured values ​​was comparable to that in the simulation.

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

[0055] 10...Antenna device, 100...First antenna element, 110...Rectangular section, 110a~110d...Radiation section, 111...Choke section, 112...Coupling section, 120...Power supply section, 121a, 122a...First power supply line, 121b, 122b...Second power supply line, 130...Arm section, 140...Leg section, 150...Power supply circuit board, 151...First power supply port, 152...Second power supply port

Claims

1. It is a dipole antenna, Four radial sections arranged in a rectangular shape, It comprises four power supply units, each positioned at one corner of the rectangle formed by the four aforementioned radiating units, and supplying power to the two aforementioned radiating units flanking each of those corners, The power supply voltage from a pair of power supply units located at two opposing corners to the four radiating units corresponds to one of the two orthogonal polarization directions. The power supply voltage from another set of power supply units, located at two opposing corners different from the aforementioned two corners, to the four radiating units corresponds to the polarization of the other of the two orthogonal polarization directions. A dipole antenna characterized by the following features.

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

3. The dipole antenna according to claim 2, characterized in that each of the four radiating sections has a coupling structure at both ends of the choke structure that widens the width of the wiring.

4. The dipole antenna according to claim 1, characterized in that two feed lines are each divided into two, extending from the center of the rectangle formed by the four radiating sections toward two pairs of opposing corners in the rectangle, and power is supplied from each of the four feed sections to the two radiating sections flanking each feed section.

5. The dipole antenna according to claim 4, characterized in that the feed line in the feed section is an open stub.

6. Legs rising from a power supply circuit board having a power supply port, Four arm sections extending in all directions from the upper end of the aforementioned leg section, It comprises a rectangular section connecting the ends of the four aforementioned arms, The two power supply lines are wired to the legs and arms. The four radial portions are formed in the rectangular portion. The dipole antenna according to claim 4, characterized by the above.

7. The aforementioned leg portion is composed of a single circuit board. The dipole antenna according to claim 6, characterized in that of the two feed lines, one 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 comprising a dipole antenna as described in claims 1 to 7, 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, An antenna device characterized by comprising the following features.

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

10. The antenna device according to claim 8, characterized in that the second antenna element constitutes an array antenna of a plurality of antenna elements arranged on the reflector.

11. The antenna device according to claim 8, characterized in that the second antenna element is provided in a position closer to the reflector than the first antenna element.

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