Twin loop antenna

Abstract

To provide an antenna which satisfies VSWR1.1 or lower over a frequency band of a use frequency in a state where a directivity deviation is kept satisfactory.SOLUTION: In a twin loop antenna 1 including a reflector 2, a first element width of first loop elements in a direction parallel to a radiation direction of first loop elements 32a1, 32a2, 32b1 and 32b2 is larger than a first thickness of the first loop elements in a direction vertical to the radiation direction of the first loop elements. A second element width of second loop elements in a direction parallel to a radiation direction of second loop elements 34a1, 34a2, 34b1 and 34b2 is larger than a second thickness of the second loop elements in a direction vertical to the radiation direction of the second loop elements. The radiation directions of the first and second loop elements are the same direction, and the loop elements are connected to feeding points 31a and 31b which are juxtaposed at upper and lower positions with respect to the loop elements. Balanced lines 33a1, 33a2, 33b1 and 33b2 extend in the radiation directions of the loop elements in ends at opposite sides of the feeding points 31a and 31b, and are connected to the first and second loop elements.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to a radiating element used for television broadcasting, and particularly to a dual-loop antenna provided with a radiating element having excellent directivity deviation and a broadened voltage standing wave ratio (VSWR).

Background Art

[0002] For example, a conventional transmission antenna system for broadcasting is an assembly of antennas with reflectors using a dual-loop antenna or a dipole antenna as a radiating element. Generally, the assembly includes a plurality of antennas with reflectors arranged on three or more planes at equal intervals on the same circumference. Such a plurality of antennas with reflectors are arranged at intervals of 120° when arranged in three planes, and at intervals of 90° when arranged in four planes. And the assembly of conventional antennas with reflectors is adjusted so that the combined directivity of the plurality of antennas with reflectors arranged on each plane becomes omnidirectional, and is mostly installed at the top of a tower.

[0003] FIG. 25A is a side view showing an example of an assembly 1000 of conventional antennas with reflectors that can be attached to a pole portion 1020 at the top of a tower. The assembly 1000 of conventional antennas with reflectors has four antennas with reflectors 1010 arranged at equal intervals (that is, at intervals of 90°) on the circumference of the pole portion 1020 in four planes. FIG. 25B is a top view of the assembly 1000 of conventional antennas with reflectors shown in FIG. 25A as viewed from the top of the tower. Referring to FIG. 25B, the assembly 1000 of conventional antennas with reflectors has four antennas with reflectors 1010 arranged in four planes at equal intervals (that is, at intervals of 90°) on the circumference of the pole portion 1020 with an attachment radius r. Here, the attachment radius r shown in FIG. 25B means the distance from the center of the pole portion 1020 to the back surface (that is, the reflector) of each antenna with reflector 1010.

[0004] For example, in the case of the antenna 1010 with four reflectors arranged in four directions, it is desirable that the horizontal directivity deviation is about 3 dB. Such a horizontal directivity deviation can be realized, for example, by setting the mounting radius r to be less than or equal to approximately 1 / 2 of the wavelength of the operating radio wave. Note that the wavelength of the operating radio wave is approximately 508 mm when the frequency f of the operating radio wave is 590 MHz, for example.

[0005] Note that when installing the above antenna on the top of an existing tower, the mounting radius r may become large. Even in such a case, in order to improve the horizontal directivity deviation, for example, in FIG. 1 of Patent Document 2, there is a description of an antenna unit including three or more radiators arranged adjacent to each other with a predetermined opening angle, and the opening angle is set so that the horizontal directivity shows a predetermined fan-shaped pattern. However, since the antenna unit of Patent Document 2 includes three or more radiators, the total weight of the antenna increases, and the load on the tower where the antenna is installed increases. Therefore, a method for improving directivity by the phase difference feeding method shown in Patent Document 1 was proposed.

[0006] FIG. 26 shows the calculation results of the directivity deviation when the mounting radius r is changed for an assembly in which four 2L double-loop antennas (described in FIG. 4 of Patent Document 1) using a phase difference feeding element (shown by a solid line as an "embodiment") as a radiating element are arranged in four directions, and an assembly in which four conventional standard double-loop antennas (described in FIG. 10 of Patent Document 1) (shown by a dashed line as a "standard double-loop") are arranged in four directions. Referring to FIG. 26, the 2L double-loop antenna (described in FIG. 4 of Patent Document 1) using a phase difference feeding element as a radiating element has an improved directivity deviation compared to the conventional standard double-loop antenna (described in FIG. 10 of Patent Document 1). In particular, even when the mounting radius r is 400 mm (that is, when the mounting radius r is larger than 1 / 2 of the wavelength (about 508 mm) at the frequency f = 590 MHz of the operating radio wave), the directivity deviation in the assembly in which four 2L double-loop antennas (described in FIG. 4 of Patent Document 1) are arranged in four directions is as good as about 3 dB. Referring to FIG. 26, the horizontal plane directivity deviation tends to increase as the mounting radius r increases. Therefore, in order to reduce the horizontal plane directivity deviation, it is desirable that the mounting radius r be as small as possible.

[0007] FIG. 27 shows the results of actually measuring the VSWR of the 2L double-loop antenna (described in FIG. 4 of Patent Document 1) of Patent Document 1 over the frequency band of the used radio wave (a 60 MHz band between fc - 30 MHz (509 MHz) and fc + 30 MHz (569 MHz) with fc = 539 MHz as the center frequency). Hereinafter, in this specification, as an example in the transmission frequency band of television broadcasting, the results for the case where the center frequency fc is 539 MHz, fc - 30 MHz is 509 MHz, and fc + 30 MHz is 569 MHz are shown. Here, from the perspective of practical implementation, it is required that this VSWR be 1.1 or less over the frequency band of the used radio wave. However, from FIG. 27, it can be seen that the 2L double-loop antenna (described in FIG. 4 of Patent Document 1) of Patent Document 1 does not satisfy the condition that the VSWR is 1.1 or less over the above-mentioned frequency band of the used radio wave. Also, in FIG. 27, the band where the VSWR is 1.1 or less is 7 MHz, which is narrower than the frequency band of the used radio wave (60 MHz band).

Prior Art Documents

Patent Documents

[0008]

Patent Document 1

Patent Document 2

Summary of the Invention

Problems to be Solved by the Invention

[0009] Therefore, it is necessary to further improve the antenna so that the VSWR satisfies the condition of being 1.1 or less over the frequency band of the used radio wave while maintaining good directivity deviation.

Means for Solving the Problems

[0010] According to the present invention, a dual-loop antenna is provided, which includes a first loop element and a second loop element. The first element width of the first loop element in a direction parallel to the radiation direction of the first loop element is greater than the first thickness of the first loop element in a direction perpendicular to the radiation direction of the first loop element. The second element width of the second loop element in a direction parallel to the radiation direction of the second loop element is greater than the second thickness of the second loop element in a direction perpendicular to the radiation direction of the second loop element. Specifically, the present invention provides a dual-loop antenna, which includes: a first loop element having a first element width in a direction parallel to the radiation direction of the first loop element and a first thickness in a direction perpendicular to the radiation direction of the first loop element, and the first element width is greater than the first thickness; a second loop element having a second element width in a direction parallel to the radiation direction of the first loop element and a second thickness in a direction perpendicular to the radiation direction of the first loop element, and the second element width is greater than the second thickness, and the second loop element is arranged vertically adjacent to the first loop element in the same direction as the radiation direction of the first loop element; a balanced line connected to a feeding point, with the end opposite to the feeding point extending in the radiation direction of the first loop element and connecting the first loop element and the second loop element; and a reflector arranged on the opposite side of the first loop element adjacent to the second loop element.

[0011] In addition, according to the present invention, another dual-loop antenna is also provided, in which at least a part of the first loop element and the second loop element forms an integrated loop element. Specifically, the present invention provides a first loop element having a first element width of the first loop element in a direction parallel to the radiation direction of the first loop element and a first thickness of the first loop element in a direction perpendicular to the radiation direction of the first loop element, wherein the first element width is greater than the first thickness; a second loop element having a second element width in a direction parallel to the radiation direction of the first loop element and a second thickness in a direction perpendicular to the radiation direction of the first loop element, wherein the second element width is greater than the second thickness, and the second loop element is disposed on the opposite side of the radiation direction of the first loop element and is parallel to the first loop element; a balanced line connected to a feeding point, with the end portion on the opposite side of the feeding point extending in the radiation direction of the first loop element and connecting the first loop element and the second loop element; and a reflector disposed adjacent to the second loop element and on the opposite side of the first loop element. At least a part of the first loop element and the second loop element forms an integrated loop element, and the integrated loop element has a common element width corresponding to the sum of the first element width and the second element width, thereby providing a dual-loop antenna. Also, it is preferable that at least a part of the common element width of the integrated loop element disposed distally from the feeding point is shorter than the common element width of the integrated loop element disposed other than distally, or that the portions of the integrated loop element facing each other proximal to the balanced line are installed with an opening angle of inclination θ with respect to the reflector. Furthermore, it is more preferable that at least a part of the common element width of the integrated loop element disposed distally from the feeding point is shorter than the common element width of the integrated loop element disposed other than distally, and that the portions of the integrated loop element facing each other proximal to the balanced line are installed with an opening angle of inclination θ with respect to the reflector. In addition, according to the present invention, an antenna assembly is provided in which any one of the above double-loop antennas is arranged on four sides with an attachment radius r, and the reflector is installed adjacent thereto such that any one of the first loop element, the second loop element, and the integrated loop element is located on the outside.

Advantages of the Invention

[0012] According to the antenna of the present invention, the first element width of the first loop element in the direction parallel to the radiation direction of the first loop element is larger than the first thickness of the first loop element in the direction perpendicular to the radiation direction of the first loop element, and the second element width of the second loop element in the direction parallel to the radiation direction of the second loop element is larger than the second thickness of the second loop element in the direction perpendicular to the radiation direction of the second loop element. Therefore, it is possible to provide an antenna in which the bandwidth at which the VSWR becomes 1.1 is broadened to 60 MHz while maintaining the horizontal plane directivity deviation at about 3 dB. Further, according to the antenna of the present invention, an integrated loop element in which the first loop element (main loop element) and the second loop element (phase difference feeding loop element) are integrated is adopted. Therefore, since there is no gap between the first loop element and the second loop element and processing is easy, cost reduction of the antenna can be expected. Furthermore, according to the antenna of the present invention, at least a part of the common element width of the integrated loop element arranged distally from the feeding point is shorter than other parts, or the parts facing each other in the proximal part of the balanced line in the integrated loop element can be installed with an opening angle of inclination θ with respect to the reflector. Therefore, it is possible to provide an antenna in which the bandwidth at which the VSWR becomes 1.1 is further broadened while maintaining the horizontal plane directivity deviation at about 3 dB.

Brief Description of the Drawings

[0013]

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Best Mode for Carrying Out the Invention

[0014] First, referring to FIG. 28A, a calculation implementation model 100a' of a standard 2L double-loop antenna corresponding to FIG. 4 of Patent Document 1 will be described. Here, the arrows with U and D indicate the vertical or perpendicular direction. This calculation implementation model 100a' is formed by installing two one-wavelength loop elements at intervals that are vertically symmetric with respect to the feeding point 131a' and connecting them with a balanced line via the feeding point 131a'. Here, the calculation implementation model 100a' includes a balanced line connected to the feeding point 131a' and extending in a vertically symmetric manner with respect to the feeding point 131a', and a first loop element 132a 1 ' and 132a 2 ' respectively connected to the ends of the balanced line, and a balanced line 133a 1 ' and 133a 2 ' having one end respectively connected to the first loop element 132a 1 ' and 132a 2 ' and extending in the direction of the reflector 120', and a second loop element 134a 1 ' and 133a 2 ' respectively connected to the other ends of the balanced line 133a 1 ' and 134a 2 '. That is, the calculation implementation model 100a' includes a configuration in which the first loop element 132a 1 ' is connected to the second loop element 134a 1 ' via the balanced line 133a 1 ', and the first loop element 132a 2 ' is connected to the second loop element 134a 2 ' via the balanced line 133a 2 '. And the first loop element 132a 1 ' and 132a 2 ' are arranged at a predetermined distance (about one-quarter wavelength of the wavelength radiated from the antenna) from the reflector 120'. Here, in the calculation implementation model 100a', the first loop element 132a 1 ' and 132a 2The first loop element 132a extending in a plane perpendicular to the radial direction of ’ (i.e., a plane parallel to the reflector 120’). 1 ’ and 132a 2 ’ and the second loop element 134a 1 ’ and 134a 2 The thickness of each element between ’ and 134a is 5 mm. On the other hand, in the calculation model 100a’, the first loop element 132a 1 ’ and 132a 2 The first loop element 132a extending in a plane parallel to the radial direction of ’ (i.e., a plane perpendicular to the reflector 120’). 1 ’ and 132a 2 ’ and the second loop element 134a 1 ’ and 134a 2 The width of each element between ’ and 134a is 3 mm.

[0015] FIG. 28B shows the calculation results of the angular dependence (horizontal plane directivity) of the phase directivity in the calculation model 100a’ of FIG. 28A. In FIG. 28B, the horizontal plane directivity has a concave shape in the vicinity of the angle 0. The fact that such a horizontal plane directivity has a concave shape in the vicinity of the angle 0 means that an improvement effect of the horizontal plane directivity can be expected when adjusting the combined directivity of an antenna with a plurality of reflectors, such as a four-sided arrangement, to be omnidirectional.

[0016] Next, referring to FIG. 29A, in the calculation model 100a’, a calculation model 100a’’ is shown in which the thickness of each element between the first loop element 132a shown in FIG. 28A 1 ’ and 132a 2 ’ and the second loop element 134a 1 ’ and 134a 2 ’ is changed from 5 mm to 45 mm. Specifically, the calculation implementation model 100a’’ is configured by installing two one-wavelength loop elements at intervals that are vertically symmetric with respect to the feeding point 131a’’, and connecting them with a balanced line through the feeding point 131a’’. Here, the calculation implementation model 100a’’ includes a balanced line connected to the feeding point 131a’’ and extending in a vertically symmetric manner with respect to the feeding point 131a’’, and first loop elements 132a 1 ’’ and 132a 2 ’’ respectively connected to the ends of the balanced line. And balanced lines 133a 1 ’’ and 133a 2 ’’ with one end respectively connected to the first loop elements 132a 1 ’’ and 133a 2 ’’, and extending in the direction of the reflector 120’’. And second loop elements 134a 1 ’’ and 134a 2 ’’ respectively connected to the other ends of the balanced lines 133a 1 ’’ and 134a 2 . That is, the calculation implementation model 100a’’ includes a configuration where the first loop element 132a 1 ’’ is connected to the second loop element 134a 1 ’’ via the balanced line 133a 1 ’’, and the first loop element 132a 2 ’’ is connected to the second loop element 134a 2 ’’ via the balanced line 133a 2 ’’. And the first loop elements 132a 1 ’’ and 132a 2 ’’ are arranged at a predetermined distance (about one-quarter wavelength of the wavelength radiated from the antenna) from the reflector 120’’. Here, in the calculation implementation model 100a’’, the first loop elements 132a 1 ’’ and 132a 2 ’’ extend in a plane perpendicular to the radiation direction of the first loop elements 132a 1 ’’ and 132a 2 ’’ (that is, a plane parallel to the reflector 120’’), and the first loop elements 132a 1 ’’ and 132a 2The thickness of each element with respect to ‘‘ is 45 mm. On the other hand, in the calculation execution model 100a’’, the first loop element 132a 1 ’’ and 132a 2 ’’ extends in a plane parallel to the radial direction (that is, a plane perpendicular to the reflector 120’’), the first loop element 132a 1 ’’ and 132a 2 ’’ and the second loop element 134a 1 ’’ and 134a 2 ’’ have an element width of 3 mm each.

[0017] FIG. 29B shows the calculation result of the angular dependence (horizontal plane directivity) of the phase directivity in the calculation execution model 100a’’ of FIG. 29A. In FIG. 29B, unlike FIG. 28B, the shape of the horizontal plane directivity has a convex shape near the angle 0. The fact that such a horizontal plane directivity has a convex shape near the angle 0 means that, for example, when adjusting the combined directivity of an antenna with a plurality of reflectors such as a four-sided arrangement to be omnidirectional, the improvement effect of the horizontal plane directivity cannot be expected. That is, even if the element width of each radiating element of the 2L double-loop antenna is widened along a plane perpendicular to the radial direction of the first loop element (a plane parallel to the reflector) as in the calculation execution model 100a’’ of FIG. 29A, an improvement in the combined directivity (horizontal plane directivity) of an antenna with a plurality of reflectors such as a four-sided arrangement cannot be expected.

[0018] Therefore, next, with reference to FIG. 1, a first calculation execution model 1 of a double-loop antenna in which the element width of each radiating element extending in a direction different from that of the calculation execution model 100a’’ (that is, a direction perpendicular to the reflector 2) is set to 20 mm each will be described. The arrows with U and D on the right side in FIG. 1 indicate the vertical or vertical direction. Specifically, the first calculation implementation model 1 includes a radiation element 3a and a radiation element 3b having the same configuration as the radiation element 3a, which is arranged adjacent to the radiation element 3a in the same direction and below it. Here, the radiation element 3a is formed by installing two one-wavelength loop elements at intervals that are vertically symmetric with respect to the feeding point 31a and connecting them with a balanced line via the feeding point 31a. Here, the radiation element 3a includes a balanced line connected to the feeding point 31a and extending symmetrically above and below the feeding point 31a, and first loop elements 32a 1 and 32a 2 respectively connected to the balanced line at both ends, and balanced lines 33a 1 and 32a 2 each extending in the direction of the reflector 2. And balanced lines 33a 1 and 33a 2 respectively connected to the balanced line at both ends, and balanced lines 33a 1 and 33a 2 respectively connected to the other ends of the balanced lines 33a 1 and 34a 2 and 34a 1 wherein the first loop element 32a 1 is connected to the second loop element 34a 1 via the balanced line 33a 2 and the first loop element 32a 2 is connected to the second loop element 34a 2 via the balanced line 33a 1 and 32a 2 are arranged at a predetermined distance (about one-quarter wavelength of the wavelength radiated from the antenna) from the reflector 2. Here, in the radiation element 3a, the first loop elements 32a 1 and 32a 2 extend in a plane parallel to the radiation direction of the first loop elements 32a 1 and 32a 2 and the second loop elements 34a 1 and 34a 2 and 34a 1 and 32a2 The first loop elements 32a extend in a plane perpendicular to the radial direction (i.e., a plane parallel to the reflector 2). 1 and 32a 2 and the first thickness and the second loop elements 34a 1 and 34a 2 each have a second thickness of 3 mm. Similarly, the radiation element 3b is formed by installing two one-wavelength loop elements at intervals that are vertically symmetric with respect to the feeding point 31b and connecting them with a balanced line via the feeding point 31b. Here, the radiation element 3b includes a balanced line that is connected to the feeding point 31b and extends symmetrically above and below the feeding point 31b, and first loop elements 32b 1 and 32b 2 and the first loop elements 32b 1 and 32b 2 each having one end connected thereto, and balanced lines 33b 1 and 33b 2 that extend in the direction of the reflector 2 from the ends of the balanced line, and second loop elements 34b 1 and 34b 2 each connected to the other end of the balanced line 33b 1 and 34b 2 That is, the radiation element 3b includes a configuration in which the first loop elements 32b 1 are connected to the second loop elements 34b 1 via the balanced lines 33b 1 and the first loop elements 32b 2 are connected to the second loop elements 34b 2 via the balanced lines 33b 2 And the first loop elements 32b 1 and 32b 2 are arranged at a predetermined distance (about one-quarter wavelength of the wavelength radiated from the antenna) from the reflector 2. Here, in the radiation element 3b, the first loop elements 32b 1 and 32b 2 extend in a plane parallel to the radiation direction (i.e., a plane perpendicular to the reflector 2), the first loop elements 32b 1 and 32b 2 and the second loop elements 34b1 and 34b 2 The element width of each of them and 34b is 20 mm. On the other hand, in the radiating element 3b, the first loop element 32b 1 and 32b 2 extends in a plane perpendicular to the radiation direction (i.e., a plane parallel to the reflector 2). The first loop element 32b 1 and 32b 2 has a first thickness, and the second loop element 34b 1 and 34b 2 has a second thickness of 3 mm each.

[0019] FIG. 2 shows the calculation results of the VSWR characteristics in the first calculation implementation model 1 shown in FIG. 1. Referring to FIG. 2, it can be seen that in the case of the first calculation implementation model 1 (shown by a solid line as "Type1"), a band with a VSWR of 1.1 or less is obtained as fc ± 30 MHz (i.e., 60 MHz).

[0020] FIG. 3A shows a graph comparing the calculation results of the intensity directivity of the antenna unit of the first calculation implementation model 1 (shown by a solid line as "Type1") with the calculation results of the intensity directivity of the antenna unit of the conventional product calculation implementation model 100a' (shown by a broken line as "conventional product"). Further, FIG. 3B shows a graph comparing the calculation results of the phase directivity of the antenna unit of the first calculation implementation model 1 (shown by a solid line as "Type1") with the calculation results of the phase directivity of the antenna unit of the conventional product calculation implementation model 100a' (shown by a broken line as "conventional product"). First, referring to the graph of the phase directivity in FIG. 3B, when comparing the change in phase near angles ±60°, the antenna unit of the first calculation implementation model 1 has a substantially constant phase amount, while the antenna unit of the conventional product calculation implementation model 100a' has a convex shape with a peak near angle 0 at the top. Therefore, it is expected that the antenna unit of the first calculation implementation model 1 can obtain better (with less directivity deviation) horizontal plane directivity in the four-sided arrangement assembly than the antenna unit of the conventional product calculation implementation model 100a'. In the graph of the intensity directivity in FIG. 3A, when comparing the change in intensity directivity near angles 60° and 300° (near angles ±60°), although there is a slight difference in the electric field strength between the antenna unit of the first calculation implementation model 1 and the antenna unit of the conventional product calculation implementation model 100a', the influence on the horizontal plane directivity during four-sided synthesis is minor.

[0021] Next, FIG. 4A shows a graph comparing the calculation results of the four-sided combined directivity (mounting radius r = 400 mm) for an assembly with four antennas of the first calculation implementation model 1 (shown by a solid line as "Type 1") and an assembly with four antennas of the conventional calculation implementation model 100a' (shown by a dashed line as "conventional product"). From FIG. 4A, it can be seen that for the four-sided combined directivity as well, the first calculation implementation model 1 is improved compared to the conventional calculation implementation model 100a'. Also, FIG. 4B shows the calculation results regarding the characteristics of an assembly with four antennas of the first calculation implementation model 1 in the frequency band of the used radio wave (fc ± 30 MHz). From FIG. 4B, in the case of the assembly with four antennas of the first calculation implementation model 1, the directivity deviation during four-sided combination over the frequency band of the used radio wave (fc ± 30 MHz) has been improved from 5 dB of the conventional product to 4.4 dB.

[0022] Next, referring to FIGS. 5A to 5C, the first element width w of the first loop element, which extends in a plane parallel to the radiation direction of the first loop element of the first calculation implementation model 1 shown in FIG. 1 1 and the second element width w of the second loop element 2 are considered for the four-sided combined directivity when changed. Here, FIG. 5A is the same as the first calculation implementation model 1 shown in FIG. 1 (that is, the first element width w of the first loop radiation element 32a 1 and the second element width w of the second loop element 2 are each set to 20 mm). FIG. 5B shows the first element width w of the first loop element 32a-1 of the first calculation implementation model 1 1 and the second element width w of the second loop element 34a-1 2 each set to 30 mm. FIG. 5C shows the first element width w of the first loop element 32a-1 of the first calculation implementation model 1 1 and the second element width w of the second loop element 34a-1 2 each set to 40 mm. In the case of FIG. 5C, the first loop element and the second loop element are integrated with each other to form an integrated loop element having a common element width W (this common element width W is 90 mm).

[0023] FIG. 6 shows the calculation results of the four-sided combined directivity when the mounting radius r is 400 mm for each calculation implementation model in which the first element width w 1 and the second element width w 2 shown in FIGS. 5A to 5C are changed to 20 mm, 30 mm, and 40 mm, respectively. From FIG. 6, it can be seen that the first element width w 1 and the second element width w 2 shown in FIGS. 5A to 5C do not show a significant change in the four-sided combined directivity deviation regardless of whether they are 20 mm, 30 mm, or 40 mm. In particular, in the case of the integrated loop element shown in FIG. 5C, there is no slit portion (gap) between the first loop element and the second loop element, and since processing of such a slit portion is not required, it is advantageous from the viewpoint of manufacturing cost.

[0024] FIG. 7 shows the second calculation implementation model 1 2 The second calculation implementation model 1 2 is different from the first calculation implementation model 1 in FIG. 1 mainly in that it has an integrated loop element without a slit portion (gap) between the first loop element and the second loop element. Specifically, the second calculation implementation model 1 2 includes a radiation element 3a' and a radiation element 3b' having the same configuration as the radiation element 3a' and arranged adjacent to the radiation element 3a' in the same direction and below it. Here, the radiation element 3a' is formed by installing two one-wavelength loop elements at intervals that are vertically symmetric with respect to the feeding point 31a' and connecting them with a balanced line via the feeding point 31a'. Here, the radiation element 3a' is connected to the feeding point 31a', and includes a balanced line that extends so as to be vertically symmetric with respect to the feeding point 31a', and balanced line paths 33a 1 ' and 33a 2 ' that are respectively connected to the ends of the balanced line and extend in the direction of the reflector 2, and an integrated loop element 35a 1 ' and 33a 2 ' that are respectively connected to the other ends of the balanced line paths 33a 1 ' and 35a 2 ' (the first loop element and the second loop element in the first calculation implementation model 1 are integrated). And the integrated loop element 35a 1’, 35a 2 ’ is arranged at a predetermined distance (about one - quarter wavelength of the wavelength radiated from the antenna) away from the reflector 2. Here, in the radiating element 3a’, the integrated loop element 35a 1 ’, 35a 2 ’ extends in a plane parallel to the radiation direction of the integrated loop element 35a 1 ’, 35a 2 ’ The common element width W of the integrated loop element 35a 1 ’, 35a 2 ’ extends in a plane parallel to the radiation direction of the integrated loop element 35a 1 ’, 35a 2 ’ The thickness of the element of the integrated loop element 35a Similarly, the radiating element 3b’ is formed by installing two one - wavelength loop elements at symmetric intervals with respect to the feeding point 31b’ and connecting them with a balanced line via the feeding point 31b’. Here, the radiating element 3b’ includes a balanced line connected to the feeding point 31b’ and extending symmetrically above and below the feeding point 31b’, and balanced lines 33b 1 ’ and 33b 2 ’ and the balanced line 33b 1 ’ and 33b 2 ’ respectively connected to the other ends of the balanced lines 33b 1 ’ and 35b 2 ’ and an integrated loop element 35b 1 ’ and 35b 2 ’ are arranged at a predetermined distance (about one - quarter wavelength of the wavelength radiated from the antenna) away from the reflector 2. Here, in the radiating element 3b’, the integrated loop element 35b 1 ’ and 35b 2 ’ extends in a plane parallel to the radiation direction of the integrated loop element 35b 1 ’ and 35b 2 ’ The common element width W of the integrated loop element 35b 1 ’ and 35b2 The integrated loop element 35b extending in a plane perpendicular to the radial direction of 1 ’s, 35b 2 The thickness of the element of ’ is 3 mm.

[0025] Fig. 8 shows a graph comparing the calculation results of the VSWR characteristics of the antenna alone of the second calculation implementation model 1 (shown by a dashed line as “Type 2”) with the calculation results of the VSWR characteristics of the antenna alone of the first calculation implementation model 1 (shown by a solid line as “Type 1”). From Fig. 8, the band where the VSWR is 1.1 or less is wider in the second calculation implementation model 1 than in the first calculation implementation model 1 2 Fig. 9A shows a graph comparing the calculation results of the intensity directivity of the antenna alone of the second calculation implementation model 1 (shown by a dashed line as “Type 2”) with the calculation results of the intensity directivity of the antenna alone of the first calculation implementation model 1 (shown by a solid line as “Type 1”). Referring to Fig. 9A, when comparing the changes in the intensity directivity near angles 60° and 300° (near angles ±60°), the antenna alone of the second calculation implementation model 1 2 has a slightly different electric field strength compared to the antenna alone of the first calculation implementation model 1, but the influence on the horizontal plane directivity during four-plane synthesis is minor. Fig. 9B shows a graph comparing the calculation results of the phase directivity of the antenna alone of the second calculation implementation model 1 (shown by a dashed line as “Type 2”) with the calculation results of the phase directivity of the antenna alone of the first calculation implementation model 1 (shown by a solid line as “Type 1”). Referring to Fig. 9B, when comparing the changes in the phase near angles ±60°, both the antenna alone of the second calculation implementation model 1

[0026] Fig. 9A shows a graph comparing the calculation results of the intensity directivity of the antenna alone of the second calculation implementation model 1 (shown by a dashed line as “Type 2”) with the calculation results of the intensity directivity of the antenna alone of the first calculation implementation model 1 (shown by a solid line as “Type 1”). Referring to Fig. 9A, when comparing the changes in the intensity directivity near angles 60° and 300° (near angles ±60°), the antenna alone of the second calculation implementation model 1 2 has a slightly different electric field strength compared to the antenna alone of the first calculation implementation model 1, but the influence on the horizontal plane directivity during four-plane synthesis is minor. Fig. 9B shows a graph comparing the calculation results of the phase directivity of the antenna alone of the second calculation implementation model 1 (shown by a dashed line as “Type 2”) with the calculation results of the phase directivity of the antenna alone of the first calculation implementation model 1 (shown by a solid line as “Type 1”). Referring to Fig. 9B, when comparing the changes in the phase near angles ±60°, both the antenna alone of the second calculation implementation model 1 2 and the antenna alone of the first calculation implementation model 1 are both concave in shape. However, in Fig. 9B, the antenna alone of the second calculation implementation model 1 2 shows a slightly stronger concave shape near angles ±60° than the antenna alone of the first calculation implementation model 1. Therefore, the second calculation implementation model 1 2 and the antenna alone of the first calculation implementation model 1 are both concave in shape. However, in Fig. 9B, the antenna alone of the second calculation implementation model 1 2 shows a slightly stronger concave shape near angles ±60° than the antenna alone of the first calculation implementation model 1. Therefore, the second calculation implementation model 1 2The single antenna is expected to obtain better (less directive deviation) horizontal plane directivity in the four-sided arrangement assembly than the single antenna of the first calculation implementation model 1.

[0027] Next, Fig. 10 shows a graph comparing the calculation results of the four-sided combined directivity (mounting radius r = 400 mm) for an assembly with the antennas of the second calculation implementation model 1 (shown by a dashed line as "Type 2") arranged on four sides and an assembly with the antennas of the first calculation implementation model 1 (shown by a solid line as "Type 1") arranged on four sides. From Fig. 10, it can be seen that for the four-sided combined directivity (mounting radius r = 400 mm) as well, the second calculation implementation model 1 2 is improved compared to the first calculation implementation model 1. 2

[0028] Next, Fig. 11A is a graph showing the calculation results of the intensity directivity of the single antenna of the second calculation implementation model 1 2 in the frequency band (fc ± 30 MHz) of the used radio wave. And Fig. 11B is a graph showing the calculation results of the phase directivity of the single antenna of the second calculation implementation model 1 2 in the frequency band (fc ± 30 MHz) of the used radio wave. Here, referring to Fig. 11B, the phase directivity of the single antenna of the second calculation implementation model 1 2 2 is slightly convex in shape around an angle of ±60° when the frequency f of the used radio wave is fc - 30 MHz, but is concave in shape around an angle of ±60° when the frequency f of the used radio wave is fc and fc + 30 MHz. Therefore, the phase directivity of the single antenna of the second calculation implementation model 1 2 changes in shape from convex to concave, especially around an angle of ±60°, according to the frequency f of the used radio wave.

[0029] Next, Fig. 12 shows the calculation results of the four-sided combined directivity (mounting radius r = 400 mm) of the antennas of the second calculation implementation model 1 2 in the frequency band (fc ± 30 MHz) of the used radio wave. From Fig. 12, for the second calculation implementation model 1 2In the case of an assembly with four antennas arranged, the directivity deviation during four-way synthesis over the frequency band (fc ± 30 MHz) of the radio wave in use is about 4.6 dB. Therefore, regarding the directivity deviation during four-way synthesis over the frequency band (fc ± 30 MHz) of the radio wave in use, the second calculation implementation model 1 2 The assembly with four antennas arranged of 2 is almost the same as the assembly with four antennas arranged of the first calculation implementation model 1.

[0030] Next, in FIG. 13, in order to further improve the directivity deviation during four-way synthesis in the frequency band (fc ± 30 MHz) of the radio wave in use, the second calculation implementation model 1 2 of the integrated loop element 35a 1 ’, 35a 2 ’ among them, a part of the element width W located distally from the balanced line 3 is changed, and the third calculation implementation model 1 3 is shown. This third calculation implementation model 1 3 differs from the second calculation implementation model 1 in that a part of the element width W located distally from the balanced line is shortened. This part of the element width W 3 corresponds to the element width near the center of a part of the elements located distally from the balanced line and means the shortest element width among a part of the element widths located distally from the balanced line. 2 Specifically, the third calculation implementation model 1 3 includes the radiation element 3a’’ and a radiation element 3b’’ (not shown) having the same configuration as the radiation element 3a’’ and arranged adjacent to the lower side of the radiation element 3a’’. Here, the radiation element 3a’’ is formed by installing two one-wavelength loop elements at intervals symmetric about the feeding point 31a’’ and connecting them with a balanced line via the feeding point 31a’’. Here, the radiation element 3a’’ is connected to the feeding point 31a’’, and has a balanced line extending symmetrically above and below with respect to the feeding point 31a’’, and balanced line paths 33a connected to the ends of the balanced line and extending respectively in the direction of the reflector 2 3 ’’ and 33a 1 ’’ and, balanced line path 33a 2 ’’ and 33a 1 ’’ and 33a 2An integrated loop element 35a (formed by integrating the first loop element and the second loop element of the first calculation implementation model) respectively connected to the other ends of the 1 ’’ and 35a 2 ’’ is included. And the integrated loop element 35a 1 ’’ and 35a 2 ’’ is arranged at a predetermined distance (about one-quarter wavelength of the wavelength radiated from the antenna) away from the reflector 2. Here, the integrated loop element 35a 1 ’’ and 35a 2 ’’ extends in a plane parallel to the radiation direction of the integrated loop element 35a 1 ’’ and 35a 2 ’’ has an element width of 90 mm, except for some elements located distally from the balanced line. On the other hand, for some of the elements of the integrated loop element 35a 1 ’’ and 35a 2 ’’, the element width W 3 of the elements located distally from the balanced line is shorter than the element width (90 mm) of the other parts because some elements are cut off. Note that the configuration of the radiation element 3b’’ (not shown) is the same as that of the radiation element 3a’’, and will be omitted because it is repetitive.

[0031] Figure 14A shows the calculation results of the intensity directivity of the antenna alone when some element widths W 3 of the third calculation implementation model 1 shown in Figure 13 3 are respectively changed to 30 mm, 50 mm, 70 mm, and 90 mm. Referring to Figure 14A and comparing the changes in the intensity directivity around angles 60° and 300° (around angles ±60°), for the antenna alone of the third calculation implementation model 1 3 although there are slight differences in the electric field strength when the element widths W 3 are 30 mm, 50 mm, 70 mm, and 90 mm respectively, the influence on the horizontal plane directivity during four-plane synthesis is minor. Figure 14B shows some element widths W 3 of the third calculation implementation model 1 shown in Figure 13 3Shows the calculation results of the phase directivity of the antenna alone when it is changed to 30 mm, 50 mm, 70 mm, and 90 mm respectively. Referring to Fig. 14B, for some element widths W 3 in any of the cases of 30 mm, 50 mm, 70 mm, and 90 mm, the change in phase near the angles of ±60° has a concave shape. In particular, in Fig. 14B, the change in phase near the angles of ±60° is in a stronger concave shape when the element width W 3 is 30 mm. Therefore, in the third calculation implementation model 1 3 when the element width W 3 is 30 mm, it is expected to obtain good (low directivity deviation) horizontal plane directivity in the four-sided arrangement assembly.

[0032] Fig. 15 shows the calculation results of the four-sided combined directivity (mounting radius 400 mm) when the antenna with some element widths W 3 of the third calculation implementation model 1 3 is changed to 30 mm, 50 mm, 70 mm, and 90 mm respectively and is made into an assembly with a four-sided arrangement. Referring to Fig. 15, for the assembly with the antenna where the element width W 3 of the third calculation implementation model 1 3 is 30 mm, the four-sided combined directivity has been improved by about 3 dB.

[0033] Next, referring to Fig. 16, in addition to the change in some element widths W 3 of the third calculation implementation model 1 3 , an aspect where further characteristic improvement can be expected will be described. The balanced lines 33a 1 ’’ and 33a 2 ’’ in Fig. 16 both have a narrower element width near the feeding point 31a’’ and a wider element width far from the feeding point 31a’’ in order to achieve impedance matching with the integrated loop elements 35a 1 ’’ and 35a 2 ’’. Here, the parts including the balanced lines 33a 1 ’’ and 33a 2 in Fig. 16 are the integrated loop elements 35a 1 ’’ and 35a 2It is a component that supplies power to '', but at the same time, it also affects the phase directivity of the antenna. Therefore, by further changing the size and shape of the elements in the part including the balanced line 33a in Fig. 16 1 '' and 33a 2 '', there is room to further improve the antenna characteristics of the third calculation implementation model 1 3 .

[0034] Fig. 17A shows a part of the second calculation implementation model 1 1 ' including the integrated loop elements 35a 2 ' and 35a 2 . Here, both the integrated loop elements 35a 1 ' and 35a 2 ' have a certain common element width W (W = 90 mm) in a direction perpendicular to the reflector 2. Therefore, both the line segment A1 and the line segment A2 shown in Fig. 17A are perpendicular to the reflector 2 . On the other hand, Fig. 17B shows the fourth calculation implementation model 1 4 . In this fourth calculation implementation model 1 4 , among the integrated loop elements 35a 2 ' and 35a 1 ' of the second calculation implementation model 1 2 , the inclination θ of a part of the loop element near the feeding point 31a', that is, directly connected to the balanced lines 33a 1 ' and 33a 2 ' and facing each other, is changed so as not to be perpendicular (90°) to the reflector 2. Here, the inclination θ means the opening angles that the line segments B1 and B2 formed by the radiation element at the distal end of the feeding point 31a' and the radiation element directly connected to the balanced lines 33a 1 ' and 35a 2 ' and facing each other have with respect to the reflector 2. That is, the inclination θ is the balanced line 33a 1 ' and 33a 2 ' and 33a 1 ' and 33a 2Among some of the integrated loop elements directly connected to the ' and facing each other, they are formed by bending in a direction that separates those at the distal end of the reflector 2 from each other and brings those at the proximal end of the reflector 2 closer to each other. In addition, a fourth calculation implementation model 1 in which the inclination θ shown in FIG. 17B is changed from 90° 4 In this case, the integrated loop element 35a 1 ', 35a 2 Among them, for the balanced lines 33a 1 ' and 33a 2 The common element width W of the directly connected and facing parts to the ' is the same as that of the integrated loop element 35a in FIG. 17A 1 ', 35a 2 ' (W = 90 mm). On the other hand, among the integrated loop elements 35a 1 ', 35a 2 Among them, for the balanced lines 33a 1 ' and 33a 2 The element width W of the part facing the ' 4 Is the element width corresponding to the inclination θ (that is, W 4 ≒ Wsinθ). And in FIG. 17C, as an example, a fourth calculation implementation model 1 in which the inclination θ shown in FIG. 17B is 60° 4 A part of is shown. Specifically, the fourth calculation implementation model 1 4 Includes a radiation element 3a''' and a radiation element 3b''' (not shown) having the same configuration as the radiation element 3a''' and arranged adjacent to the lower side of the radiation element 3a'''. Here, the radiation element 3a''' is formed by installing two one-wavelength loop elements at intervals symmetric about the feeding point 31a''', and connecting them with a balanced line via the feeding point 31a'''. Here, the radiation element 3a''' is connected to the feeding point 31a''', and has a balanced line extending symmetrically above and below with respect to the feeding point 31a''', and balanced lines 33a 1 ''' and 33a 2 ''' respectively connected to the ends of the balanced line and extending in the direction of the reflector 2, and the integrated loop elements 35a 1 ''' and 33a 2 ''' respectively connected to the other ends of the balanced lines 33a 1 ''', 35a2 ’’’(not shown) is included. And the integrated loop element 35a 1 ’’’, 35a 2 ’’’(not shown) is arranged at a predetermined distance (about one-quarter wavelength of the wavelength radiated from the antenna) from the reflector 2. Here, for the integrated loop element 35a 1 ’’’, 35a 2 ’’’(not shown), the common element width W of the portions directly connected to the balanced lines 33a 1 ’’’ and 33a 2 ’’’ is the same 90 mm as that of the integrated loop element 35a 2 of the second calculation implementation model 1 1 ’, 35a 2 ’. On the other hand, for the integrated loop element 35a 1 ’’’, 35a 2 ’’’(not shown), the element width of the portions facing the balanced lines 33a 1 ’’’ and 33a 2 ’’’ is the element width W corresponding to the inclination θ 4 (that is, W 4 ≒Wsinθ). Note that the radiation element 3b’’’(not shown) is the same as the radiation element 3a’’’, and the description is omitted because it is repetitive.

[0035] Next, Fig. 18A shows the calculation results of the angular dependence (horizontal plane directivity) of the intensity directivity of the antenna alone when the inclination θ is changed to 60°, 70°, 80°, and 90° respectively in the fourth calculation implementation model 1 4 (here, in Fig. 18A, when the inclination θ is 90°, it means the third calculation implementation model 1 3 ). Referring to Fig. 18A, it can be seen that as the inclination θ decreases to 90°, the side level of the intensity directivity (intensity in the 45° to 90° direction and -45° to -90° direction) decreases. Also, Fig. 18B shows the fourth calculation implementation model 1 4The calculation results of the angular dependence (horizontal plane directivity) of the phase directivity of the single antenna when the inclination θ is changed to 60°, 70°, 80°, and 90° respectively are shown (here, in FIG. 18B, when the inclination θ is 90°, it means the third calculation implementation model 1 3 ). Referring to FIG. 18B, in any case where the inclination θ is 60°, 70°, 80°, or 90°, the change in phase has a concave shape. This means that any of the fourth calculation implementation models 1 4 in which the inclination θ is decreased from 90° can be expected to have an effect of improving the directivity deviation during four-surface synthesis. Here, referring to FIG. 18B, it can be seen that the concave shape of the phase change when the inclination θ is decreased to 60° spreads more gently in the vicinity of angles ±90° compared to that when the inclination θ is 90°.

[0036] Next, FIG. 19 shows the four-surface synthesis directivity (mounting radius 400 mm) of the antenna when the inclination θ is changed to 60°, 70°, 80°, and 90° respectively in the fourth calculation implementation model 1 4 (note that in FIG. 19, when the inclination θ is 90°, it is the same as the third calculation implementation model 1 3 ). Referring to FIG. 19, in the fourth calculation implementation model 1 4 in which the inclination θ is decreased from 90°, the side level (intensity in the 45° to 90° direction and -45° to -90° direction) decreases, so that the drop in intensity in the ±45° direction during four-surface synthesis is reduced and improved. Here, the directivity in the 0° to 90° direction of the four-surface synthesis directivity is mainly obtained by the sum of the intensity in the 0° to 45° direction of the antenna directed in the 0° direction and the intensity in the -45° to -90° direction of the antenna directed in the 90° direction. On the other hand, in the case of the vicinity of the 22.5° direction (the middle direction between 0° and 45°) of the four-surface synthesis directivity (the part where there is a drop in intensity), it is obtained by the difference between the intensity in the 0° to 45° direction of the antenna directed in the 0° direction and the intensity in the -45° to -90° direction of the antenna directed in the 90° direction. Therefore, the fourth calculation implementation model 1 4When the antenna faces the 0° direction, by setting the inclination θ to 60°, the intensity in the 45° to 90° direction (or -45° to -90° direction) decreases, leading to an improvement in the directivity deviation during four-way synthesis.

[0037] Figure 20 shows the fifth calculation implementation model 1 5 as shown. This fifth calculation implementation model 1 5 mainly combines the third calculation implementation model 1 3 and the fourth calculation implementation model 1 4 together. Specifically, the fifth calculation implementation model 1 5 includes a radiation element 3a'''' and a radiation element 3b'''' having the same configuration as the radiation element 3a'''' and arranged adjacent to the lower side of the radiation element 3a''''. Here, the radiation element 3a'''' is formed by installing two one-wavelength loop elements at intervals that are vertically symmetric with respect to the feeding point 31a'''', and connecting them with a balanced line through the feeding point 31a'''',. Here, the radiation element 3a'''' is connected to the feeding point 31a'''', and includes a balanced line that extends symmetrically above and below with respect to the feeding point 31a'''', and balanced line paths 33a 1 '''' and 33a 2 '''' that are respectively connected to the ends of the balanced line and extend in the direction of the reflector 2, and an integrated loop element 35a 1 '''' and 33a 2 '''' that are respectively connected to the other ends of the balanced line paths 33a 1 '''' and 33a 2 '''' (where the first loop element and the second loop element of the first calculation implementation model 1 are integrated). And the integrated loop elements 35a 1 '''' and 35a 2 '''' are arranged at a predetermined distance (about one-fourth of the wavelength radiated from the antenna) from the reflector 2. Here, among the integrated loop elements 35a 1 '''' and 35a 2 '''', the balanced line paths 33a 1 '''' and 33a 2The element widths of the elements directly connected to and facing each other in the “””” are the second calculation implementation model 1 2 of the integrated loop element 35a 1 ’, 35a 2 ’ are the same 90 mm as (that is, the integrated loop element 35a 1 ””””, 35a 2 ”””” is the balanced line 33a 1 ”””” and 33a 2 ””””. Except for some elements located distally from, the second calculation implementation model 1 2 of the integrated loop element 35a 1 ’, 35a 2 ’ have the same element width). And the elements directly connected to and facing each other in the balanced line 33a 1 ”””” and 33a 2 ”””” have opening angles of inclination θ = 60° with respect to the reflector 2 obtained from the fourth calculation implementation model 1 4 respectively. And among the integrated loop elements 35a 1 ””””, 35a 2 ””””, the element widths W 1 of some elements located distally from the balanced line 33a 2 ”””” and 33a 3 are 30 mm obtained from the third calculation implementation model 1 3 . Similarly, the radiating element 3b”””” is formed by installing two one - wavelength loop elements at intervals symmetric about the feeding point 31b”””” and connecting them with a balanced line through the feeding point 31b””””. Here, the radiating element 3b”””” is connected to the feeding point 31b””””, and includes a balanced line that extends symmetrically above and below with respect to the feeding point 31b””””, and balanced lines 33b 1 ”””” and 33b 2 ”””” that are respectively connected to the ends of the balanced line and extend in the direction of the reflector 2, and the integrated loop element 35b 1 ”””” and 33b 2 ”””” that are respectively connected to the other ends of the balanced lines 33b 1 ””””, 35b 2includes “”. And the integrated loop element 35b 1 “”, 35b 2 “” is arranged at a predetermined distance (about one - quarter wavelength of the wavelength radiated from the antenna) away from the reflector 2. Here, the integrated loop element 35b 1 “”, 35b 2 Among “” of the balanced line 33b 1 and 33b 2 the element widths of the elements directly connected to and facing each other are the same 90 mm as that of the integrated loop element 35b 2 in the second calculation implementation model 1 1 ‘, 35b 2 ‘ (that is, except for some elements located distally from the balanced line 33b 1 “”, 35b 2 “”, the integrated loop element 35b 1 “” and 33b 2 “” has the same element width as that of the integrated loop element 35b 2 in the second calculation implementation model 1 1 ‘, 35b 2 ‘). And the elements directly connected to and facing each other of the balanced line 33b 1 “” and 33b 2 “” each have an opening angle with an inclination θ = 60° with respect to the reflector 2 obtained from the fourth calculation implementation model 1 4 . On the other hand, among the integrated loop element 35b 1 “”, 35b 2 “”, the element width W 1 at the center of some elements located distally from the balanced line 33b 2 “” and 33b 3 is 30 mm obtained from the third calculation implementation model 1 3 .

[0038] In FIG. 21, the fifth calculation implementation model 1 (shown by a dotted line as “Type5”) 5The calculation results of comparing the VSWR characteristics of the single antenna 5 with those of the single antenna of the first calculation implementation model 1 (shown by the solid line as "Type 1") are shown. Referring to FIG. 21, both the single antenna of the fifth calculation implementation model 1 5 and the single antenna of the first calculation implementation model 1 are 1.1 or less in the frequency band of the used radio wave (the band of fc ± 30 MHz). Also, referring to FIG. 21, the band where the VSWR is 1.1 or less is wider and improved in the fifth calculation implementation model 1

[0039] than in the first calculation implementation model 1. 5 FIG. 22A shows the calculation results of the angular dependence (horizontal plane directivity) of the intensity directivity of the single antenna when the frequency f of the used radio wave is changed in the range of fc ± 30 MHz in the fifth calculation implementation model 1. From FIG. 22, it can be seen that as the frequency f of the used radio wave increases, the side level of the intensity directivity (intensity in the directions of 45° to 90° and -45° to -90°) decreases. Also, FIG. 22B shows the calculation results of the phase directivity of the single antenna when the frequency f of the used radio wave is changed in the range of fc ± 30 MHz in the fifth calculation implementation model 1. From FIG. 22B, in the range of fc ± 30 MHz of the frequency f of the used radio wave, all the phase changes are in a concave shape. This means that in the fifth calculation implementation model 1 5 the improvement effect of the directivity deviation during the four-way synthesis can be expected over the frequency band of the used radio wave (the band of fc ± 30 MHz). Referring to FIG. 22B, as the frequency f of the used radio wave increases, the phase change near the angles of 45° to 90° and -45° to -90° becomes larger. 5 FIG. 23 shows the fifth calculation implementation model 1

[0040] FIG. 23 shows the fifth calculation implementation model 1 5The calculation results of the four-sided combined directivity (mounting radius: 400 mm) of the antenna are shown when the frequency f of the radio wave used is changed within the range of fc ± 30 MHz, respectively. From FIG. 23, as the frequency f of the radio wave used increases, the directivity deviation during four-sided combination decreases. Here, from FIG. 23, when the frequency of the radio wave used is fc - 30 MHz, the directivity deviation during four-sided combination is 3.3 dB; when the frequency of the radio wave used is fc, the directivity deviation during four-sided combination is 3 dB; when the frequency of the radio wave used is fc + 30 MHz, the directivity deviation during four-sided combination is 2.7 dB. Therefore, for the fifth calculation implementation model 1 5 the directivity deviation during four-sided combination is good over the frequency band of the radio wave used (the band of fc ± 30 MHz).

[0041] Therefore, in order to confirm that the VSWR band and the four-sided combined directivity deviation satisfy the desired target values, a prototype based on the fifth calculation implementation model 1 5 was fabricated, and measurement values were obtained for the intensity directivity of the antenna alone, the phase directivity of the antenna alone, the VSWR band, and the four-sided combined directivity deviation. FIG. 24A shows the measurement values of the intensity directivity of the antenna alone in the prototype based on the fifth calculation implementation model 1 5 Referring to FIG. 24A, the measurement values of the intensity directivity of the antenna alone in the prototype based on the fifth calculation implementation model 1 5 were almost equivalent to the calculation results of the intensity directivity of the antenna alone in the fifth calculation implementation model 1 shown in FIG. 22A 5 Also, FIG. 24B shows the measurement values of the phase directivity of the antenna alone in the prototype based on the fifth calculation implementation model 1 5 Referring to FIG. 24B, the measurement values of the phase directivity in the prototype based on the fifth calculation implementation model 1 5 were almost equivalent to the calculation results of the phase directivity in the fifth calculation implementation model 1 shown in FIG. 22B 5 And, FIG. 24C shows, when the frequency f of the radio wave used is changed within the range of fc ± 30 MHz, respectively, the fifth calculation implementation model 1 5 ​Shows the measured values of the four-sided synthetic directivity (mounting radius 400 mm) in the prototype based on this. Here, referring to FIG. 24C, when the frequency of the used radio wave is fc - 30 MHz, the directivity deviation during four-sided synthesis is 3.3 dB, when the frequency of the used radio wave is fc, the directivity deviation during four-sided synthesis is 2.3 dB, and when the frequency of the used radio wave is fc + 30 MHz, the directivity deviation during four-sided synthesis was 2.5 dB. Therefore, the fifth calculation implementation model 1 5 The directivity deviation during four-sided synthesis in the prototype based on this satisfied about 3 dB over the frequency band of the used radio wave (the band of fc ± 30 MHz). Furthermore, FIG. 24D shows the measured values of the VSWR characteristics in the prototype based on the fifth calculation implementation model 1 5 Referring to FIG. 24D, over the frequency band of the used radio wave (the band of fc ± 30 MHz), in the prototype based on the fifth calculation implementation model 1 5 the result that the VSWR was 1.1 or less was obtained.

Industrial Applicability

[0042] The present invention has been described by taking an example of an antenna used for television broadcasting. However, those skilled in the art will be able to understand that the present invention can be applied not only to such antennas for television broadcasting but also to antennas for all applications.

Explanation of Signs

[0043] 1, 1 2 , 1 3 , 1 4 , 1 5 Antenna with reflector 2, 120’, 120’’ reflectors 3a, 3b, 130a’ radiating elements 31a, 31b, 131a’ feeding points 32a 1 , 32a 2 , 32b 1 , 32b 2 First loop element 33a 1 , 33a 2 , 33b1 , 33b 2 Balanced line 34a 1 , 34a 2 , 34b 1 , 34b 2 Second loop element Integrated loop elements 35a, 35a’, 35a’’, 35a’’’ r Mounting radius

Claims

1. a first loop element having a first element width in a direction parallel to a radial direction of the first loop element and a first thickness in a direction perpendicular to the radial direction of the first loop element, the first element width being greater than the first thickness; a second loop element having a second element width in a direction parallel to the radial direction of the first loop element and a second thickness in a direction perpendicular to the radial direction of the first loop element, the second element width being greater than the second thickness; and a second loop element facing in the same direction as the radial direction of the first loop element and juxtaposed above and below the first loop element; a balanced line connected to a feed point, the end opposite to the feed point extending in a radial direction of the first loop element and connected to the first loop element and the second loop element; a reflector disposed adjacent to the second loop element and opposite the first loop element; A twin loop antenna comprising:

2. a first loop element having a first element width in a direction parallel to a radial direction of the first loop element and a first thickness in a direction perpendicular to the radial direction of the first loop element, the first element width being greater than the first thickness; a second loop element that is arranged parallel to the first loop element on the opposite side of the first loop element in the radial direction and has a second element width in a direction parallel to the radial direction of the first loop element and a second thickness in a direction perpendicular to the radial direction of the first loop element, the second element width being greater than the second thickness; a balanced line connected to a feed point, the end opposite to the feed point extending in a radial direction of the first loop element and connected to the first loop element and the second loop element; a reflector disposed adjacent to the second loop element and opposite the first loop element; It is equipped with A dual loop antenna, wherein at least a portion of the first loop element and the second loop element form an integrated loop element, and the integrated loop element has a common element width corresponding to the sum of the first element width and the second element width.

3. The dual loop antenna of claim 2 , wherein at least a portion of a common element width of the integral loop elements disposed distally from the feed point is shorter than a common element width of the integral loop elements disposed other than at the distal position.

4. 3. The twin loop antenna according to claim 2, wherein portions of the integrated loop elements facing each other in the vicinity of the balanced line are disposed at an opening angle of θ with respect to the reflector.

5. At least a portion of a common element width of the integral loop elements disposed distally from the feed point is shorter than a common element width of the integral loop elements disposed other than the distal portion; 3. The twin loop antenna according to claim 2, wherein portions of the integrated loop elements facing each other in the vicinity of the balanced line are disposed at an opening angle of θ with respect to the reflector.

6. An antenna assembly comprising a dual loop antenna as described in any one of claims 1 to 5 arranged on four sides with an installation radius r, and the reflector is installed adjacent to the first loop element, the second loop element, and the integrated loop element so that either one of them is positioned on the outside.

Images