JP2013021562A - Non-directional antenna, and non-directional antenna array - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a non-directional antenna capable of implementing downsizing of the antenna and easily performing phase adjustment.SOLUTION: A non-directional antenna 100 comprises: an oblong dielectric board 1; a conductive film 12 formed on one face of the dielectric board 1; U-shaped slots 2 and 3 formed on the conductive film; a metal tube 4 that is arranged so as to cover the U-shaped slots 2 and 3 and configures a passive element; and microstrip lines 5 and 6 that are formed on another face of the dielectric board 1 and supply the U-shaped slots 2 and 3 with power. The entire length of each of the U-shaped slots 2 and 3 is λ/4 to λ/2, and the length of the metal tube 4 is equal to or shorter than λ/2.

Description

  The present invention relates to an omnidirectional antenna and an omnidirectional antenna array, and more particularly to an omnidirectional antenna and an omnidirectional antenna array used in a mobile communication system such as a PHS or a mobile phone.

  In mobile communication base station antennas used in mobile communication systems typified by PHS and mobile phones, vertically polarized antennas having a non-directional directivity in the horizontal plane are used.

  FIG. 15 is a perspective view showing a configuration of a conventional omnidirectional antenna. The antenna of FIG. 15 includes a dielectric substrate 151, a patch antenna 152 that constitutes a primary radiation element, a cylindrical metal body 153 that constitutes a parasitic element, a microstrip line 154, and a feeding terminal 156. Yes.

  In this antenna, the excitation power input to the feeding terminal 156 is fed to the patch antenna 152 via the microstrip line 154, and the patch antenna 152 is excited. The parasitic element made of the cylindrical metal body 153 is excited by the electromagnetic wave radiated from the patch antenna 152, and a high-frequency current is induced on the outer surface of the cylindrical metal body 153.

This induced current flows in a direction parallel to the central axis of the cylindrical metal body 153 and has a uniform amplitude in the circumferential direction. Therefore, the electromagnetic wave radiated from the induced current becomes an omnidirectional pattern on a plane perpendicular to the central axis of the cylindrical metal body 153, that is, in a horizontal plane.
Here, in the omnidirectional antenna of FIG. 15, when the diameter of the antenna is increased, the coupling between the patch antenna 152 and the cylindrical metal body 153 is weakened, and as a result, the bandwidth of the antenna is narrowed. For this reason, the conventional omnidirectional antenna has a problem that the diameter of the antenna cannot be increased so as to have a desired bandwidth.

  In order to solve the above problem, as shown in FIG. 16, a dielectric substrate 161, a rectangular annular slot 162, a cylindrical metal body 163 constituting a parasitic element, a microstrip line 164, and a feeding terminal 166 An antenna comprising: has been proposed. In the antenna of FIG. 16, a conductive film (not shown) made of a metal thin film is formed on the surface side of the dielectric substrate 161, and the conductive film includes a first portion surrounded by the annular slot 2, It is comprised from the other 2nd part. The first portion of the conductive film constitutes a ground conductor, and the ground conductor and the microstrip line 164 constitute a power feeding circuit. Further, the tip of the microstrip line 164 extends to the second portion of the conductive film, and thereby electromagnetically coupled power is supplied to the annular slot 162 constituting the primary radiation element. According to this antenna, it is possible to increase the inner diameter of the cylindrical metal body constituting the parasitic element without narrowing the bandwidth.

JP-A-11-55025

  However, when a dual-frequency array antenna is configured using the above-described conventional antenna, since the ratio occupied by the annular slot and the feed line portion is large, the extra length feed line for phase adjustment cannot be accommodated. There is a problem that it is difficult to perform phase adjustment. In addition, since a space for accommodating the extra power feed line is required for each antenna, there is a problem that the array antenna is increased in size.

  An object of the present invention is to provide an omnidirectional antenna and an omnidirectional antenna array capable of realizing a reduction in size of an antenna and easily adjusting a phase.

  In order to achieve the above object, an omnidirectional antenna according to the present invention includes a dielectric substrate, a conductive layer formed on one surface of the dielectric substrate, and formed on the conductive layer. A slot having an open shape and an overall length of λ / 4 to λ / 2, and a feed path formed on the other surface of the dielectric substrate and extending to the inside of the slot when the slot is projected The metal ring is disposed so as to cover the slot and constitutes a parasitic element, and has a length of λ / 2 or less.

  The omnidirectional antenna of the present invention is formed on the other surface of the dielectric substrate, the first slot that radiates electromagnetic waves in the low frequency band fL and the second slot that radiates electromagnetic waves in the high frequency band fH, A first feeding path that extends to the inside of the first slot when the first slot is projected and the other surface of the dielectric substrate, and an inner side of the second slot when the second slot is projected. And the metal ring is disposed so as to cover the first slot and the second slot, and the length thereof is not more than λ / 2 of the high frequency band fH.

  Further, the first power supply path and the second power supply path are disposed at both ends of the dielectric substrate.

  Furthermore, it is preferable that the open shape of the slot is disposed on the opening side of the metal ring.

  In addition, the dielectric substrate is long and can be configured even if the width dimension of the dielectric substrate is approximately λ / 5.

  Furthermore, it is preferable that a plurality of through holes are formed in the dielectric substrate along the feeding path.

  The omnidirectional antenna of the present invention further includes a pair of comb-like engagement portions that are provided on the end face of the dielectric substrate and engage with both axial end portions of the metal ring.

  In addition, the omnidirectional array antenna of the present invention is configured by arranging a plurality of the omnidirectional antennas in tandem.

  Further, between two adjacent omnidirectional antennas, a feeding path in one omnidirectional antenna and a feeding path in another omnidirectional antenna are connected via a meander unit.

  Furthermore, in the omnidirectional array antenna of the present invention, a plurality of the omnidirectional antennas are alternately arranged in tandem to constitute a three-frequency shared antenna.

  According to the present invention, both ends of the slot formed in the conductive layer have an open shape, and the total length is λ / 4 to λ / 2. And a metal ring is arrange | positioned so that a slot may be covered, and the length is (lambda) / 2 or less. Furthermore, the length of the feed path can be shortened by the open slot configuration. Therefore, it is possible to reduce the size of the antenna. Further, when an array antenna is configured by arranging a plurality of omnidirectional antennas of the present invention in tandem, a space can be formed between adjacent omnidirectional antennas, so that the feed path surplus length for phase adjustment is in a meander shape. Therefore, the phase adjustment can be easily performed.

1 is a perspective view schematically showing a configuration of an omnidirectional antenna according to a first embodiment of the present invention. It is a top view of the omnidirectional antenna of FIG. 1, (a) is the figure seen from the electrically conductive film side, (b) is the figure seen from the microstrip line side, (c) is line AA of (a). FIG. It is a figure which shows the positional relationship of the microstrip line | wire in FIG. 2, and a U-shaped slot. It is a figure which shows the comparison of the characteristic of the omnidirectional antenna which concerns on this invention, and the conventional omnidirectional antenna, (a) is a characteristic of the conventional omnidirectional (loop type) slot antenna, (b) is this invention. Shows the characteristics of the omnidirectional (U-shaped) slot antenna. It is a figure which shows roughly the structure of the omnidirectional array antenna which concerns on this embodiment. It is a figure which shows the characteristic of the 1.9 GHz band of the omnidirectional array antenna of FIG. 5, (a) is a vertical in-plane gain, (b) shows a horizontal plane directional characteristic. It is a figure which shows the characteristic of a 2.56 GHz band of the omnidirectional array antenna of FIG. 5, (a) is a vertical in-plane gain, (b) shows a horizontal plane directional characteristic. It is a figure which shows schematically the structure of the omnidirectional antenna which concerns on 2nd Embodiment of this invention, (a) is a perspective view, (b) is sectional drawing in alignment with line BB of (a). It is a figure which compares the characteristic of the omnidirectional antenna in which the through-hole is not provided in the dielectric substrate, and the omnidirectional antenna in which the through-hole is provided. It is a figure explaining the fixing method of the metal tube in FIG. 8, (a) is a top view of a dielectric substrate, (b) shows the state by which the metal tube was fixed to the dielectric substrate. It is a figure which shows the modification of the omnidirectional array antenna of FIG. 5, (a) 1st modification, (b) shows 2nd modification, (c) shows 3rd modification. It is a figure which shows the modification of the omnidirectional antenna of FIG. It is a figure which shows the modification of the slot antenna in FIG. 1, (a) shows a 1st modification, (b) shows a 2nd modification. It is a figure which shows the modification of the stripline in FIG. 1, (a) shows a 1st modification, (b) shows a 2nd modification. It is a perspective view which shows the structure of the conventional omnidirectional antenna. It is a perspective view which shows the structure of the other conventional omnidirectional antenna.

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

  FIG. 1 is a perspective view schematically showing a configuration of an omnidirectional antenna according to a first embodiment of the present invention. 2 is a plan view of the omnidirectional antenna of FIG. 1, where (a) is a view from the conductive film side, (b) is a view from the microstrip line side, and (c) is a view from (a). It is sectional drawing which follows line AA.

  As shown in FIG. 1, the omnidirectional antenna 100 includes a long dielectric substrate 1, a conductive film 12 (conductive layer) formed on one surface of the dielectric substrate, and formed on the conductive film. U-shaped slots 2 and 3 (first and second slots), a metal tube 4 which is disposed so as to cover the slots 2 and 3 and constitutes a parasitic element, and the other surface of the dielectric substrate 1 And microstrip lines 5 and 6 (first and second feed lines) for supplying power to the U-shaped slots 2 and 3.

  The dielectric substrate 1 is a plate-like body constituting an electrical insulator, and has a length of 100 mm, a width of 19.8 mm, and a thickness of 0.8 mm, for example. The width dimension of the dielectric substrate 1 is designed to be approximately λ / 5, for example. The conductive film 12 is a film having a predetermined thickness formed on almost the entire surface of one side of the dielectric substrate 1 and has a thickness of, for example, 35 μm.

  The U-shaped slots 2 and 3 are arranged in tandem in the longitudinal direction of the dielectric substrate 1 and constitute a dual-frequency antenna (FIG. 2A). In this embodiment, the U-shaped slot 2 radiates an electromagnetic wave in a low frequency band fL such as 1.9 GHz, and the U-shaped slot 3 radiates an electromagnetic wave in a high frequency band fH of 2.56 GHz. It is. The depths of the U-shaped slots 2 and 3 are the same as the thickness of the conductive film 12, and are formed through the conductive film 12 (FIG. 2C). In the present embodiment, the open shapes of the U-shaped slots 2 and 3 are respectively arranged on the opening side of the metal tube 4. The overall length of the U-shaped slot 2 is, for example, λ / 4 to λ / 2, and the overall length of the U-shaped slot 3 is also, for example, λ / 4 to λ / 2.

  The metal tube 4 is a tube having a substantially circular cross section arranged so as to cover almost the entire surface of the U-shaped slots 2 and 3, the length thereof is λ / 2 of the high frequency band fH, the inner diameter is 20 mm, the thickness The thickness is 0.1 mm. The metal tube 4 is a flexible member that is elastically deformed in the radial direction. When attaching the metal tube 4 to the dielectric substrate 1, the dielectric substrate 1 is inserted while the outer peripheral surface of the metal tube 4 is pressed in the radial direction, and the pressing is released. It is clamped at a predetermined position.

  In the present embodiment, the metal tube 4 is a tube having a substantially circular cross section, but is not limited thereto, and may be an annular body having a substantially elliptical cross section or a substantially polygonal cross section. The metal tube 4 is arranged so as to cover almost the entire surface of the U-shaped slots 2 and 3, but is not limited to this, and at least the surface of the U-shaped slots 2 and 3. You may arrange | position so that a part may be covered.

  The microstrip lines 5 and 6 are formed at the end in the width direction of the dielectric substrate 1 (FIG. 2B). The microstrip line 5 has an L-shaped branch line extending inward of the dielectric substrate 1, and a first line 51 extending in a direction perpendicular to the main line of the microstrip line 5; And a second line 52 extending in a substantially right angle direction from the end of the first line 51. The microstrip line 6 includes a first line 61 that extends in a direction perpendicular to the main line of the microstrip line 6 and a second line 62 that extends from the end of the first line 61 in a substantially right angle direction. ing. The meander portions 53a and 53b accommodate a line for improving antenna characteristics, and are arranged at a predetermined distance from the end portions of the second lines 52 and 62, respectively. A feed terminal (not shown) is disposed on the end face of the omnidirectional antenna 100, and power is supplied to the microstrip lines 5 and 6 by the feed terminal.

  FIG. 3 is a projection view showing the positional relationship between the U-shaped slots 2 and 3 and the microstrip lines 5 and 6 in FIG.

  In FIG. 3, the slot 2 includes a first slot portion 21 arranged substantially at right angles to the first line 51, and first and second ends extending from the both ends of the first slot portion 21 in a direction substantially perpendicular to the first slot portion. 2 and third slot portions 22 and 23. That is, in the present embodiment, when the first slot portion 21 and the first and second lines 51 and 52 are projected onto one plane, the first slot portion 21 is disposed substantially parallel to the first line 51. And the second line 52 is arranged so as to intersect at a substantially right angle.

  The length of the first slot portion 21 is, for example, 6 mm, and the length of the second and third slot portions 22, 23 is, for example, 23.8 mm. The first, second, and third slot portions 21, 22, and 23 have the same width and depth, and are 1 mm wide and 0.035 mm deep. The length of the first line 51 is, for example, 5.1 mm, and the length of the second line 52 is, for example, 23.5 mm. In addition, the dimension of the slot 2 and the 1st and 2nd track | line 51,52 is an illustration, and is not restrict | limited to the said value.

  The slot 3 includes a first slot portion 31 disposed substantially at right angles to the first line 61, and second and second slots extending from both ends of the first slot portion 31 in a direction substantially perpendicular to the first slot portion. 3 slots 32 and 33 are provided. That is, in the present embodiment, when the first slot portion 31 and the first and second lines 62 and 62 are projected on one plane, the first slot portion 31 is disposed substantially parallel to the first line 61. And the second line 62 is arranged so as to intersect at a substantially right angle.

  The length of the first slot portion 31 is, for example, 6.0 mm, and the length of the second and third slot portions 32, 33 is, for example, 18.6 mm. The first, second, and third slot portions 31, 32, and 33 have substantially the same width and depth, and are 1 mm wide and 0.035 mm deep. In addition, the dimension of the slot 3 and the 1st and 2nd track | line 61,62 is an illustration, and is not restrict | limited to the said value.

  In the omnidirectional antenna 100 configured as described above, the excitation power input to the feeding terminal is supplied to the U-shaped slots 2 and 3 via the microstrip lines 5 and 6, and the U-shaped slot 2 and 3 are excited. A high-frequency current is induced on the outer surface of the metal tube 4 by the electromagnetic waves radiated from the U-shaped slots 2 and 3.

  4A and 4B are diagrams showing a comparison of characteristics between the omnidirectional antenna 100 according to the present invention and a conventional omnidirectional antenna. FIG. 4A shows characteristics of a conventional omnidirectional (loop type) slot antenna. b) shows the characteristics of the omnidirectional (U-shaped) slot antenna in the present invention. In FIG. 4, the U-shaped slot 2 for the high frequency band (2.56 GHz) will be described as an example.

  The inventor has obtained the following experimental results with respect to the length of the feed line and the slot when the slot formed on the dielectric substrate 1 has a U-shape. That is, in the branch path of the microstrip line 5, the length from the main line to the position intersecting with the first slot portion 21 is Lb, and the length of the second slot portion 22 is SY, so as to obtain a predetermined impedance. On the other hand, when the conventional loop type slot is configured to obtain the same impedance as the predetermined impedance, both Lb and SY are larger than those of the U-shaped slot (FIG. 4A).

  Therefore, in the U-shaped slot in the present embodiment, the length of the branching path of the microstrip line 5, particularly the length parallel to the second slot portion 22 and the length of the second slot portion 22 are both loop-type slots. It can be a smaller value. As a result, the longitudinal dimension of the omnidirectional slot antenna 100 can be significantly reduced as compared with the loop type slot. In addition, since a sufficient space can be secured at the longitudinal end of the omnidirectional slot antenna 100, a feed line for phase adjustment, that is, the meander portions 53a and 53b can be disposed in the space. It has become.

  FIG. 5 is a diagram schematically showing the configuration of the omnidirectional array antenna according to the present embodiment.

  The omnidirectional array antenna of FIG. 5 is obtained by arranging the omnidirectional antennas 100 of FIG. 1 in tandem in the longitudinal direction. For example, the omnidirectional array antenna has a configuration in which ten omnidirectional antennas 100 in FIG. 1 are used, and its length is 860 mm. The length of the omnidirectional array antenna is an example and is not limited to the above value.

  In this omnidirectional array antenna, a U-shaped slot 2 (for a high frequency band) in one omnidirectional antenna 100 and a U-shaped slot 3 (for a low frequency band) in another adjacent omnidirectional antenna 100. For). The metal tube 4 in one omnidirectional antenna 100 and the metal tube 4 in another adjacent omnidirectional antenna 100 are arranged at a predetermined interval. In addition, the microstrip lines 5 and 6 in one omnidirectional antenna 100 are electrically connected to the microstrip lines 5 and 6 in other omnidirectional antennas 100 adjacent to each other, and end portions of the array antenna Electric power is supplied from a power supply terminal (not shown) provided in FIG. The microstrip line 5 in one omnidirectional antenna 100 and the microstrip line 5 in another omnidirectional antenna 100 are connected via a meander unit 53 for performing phase adjustment.

  Here, when a dual-frequency antenna is manufactured under the condition that the longitudinal dimension of the array antenna is limited, if an omnidirectional antenna is manufactured for each frequency, the length becomes long. It is arranged to reduce the size. At this time, the minimum value of the element interval is determined by the length of the metal tube 4, and the maximum value is determined by the wavelength on the high frequency side so as to avoid the generation of an unnecessary wave called a grating lobe. Therefore, depending on the combination of frequencies, the omnidirectional antenna may not fit in the element spacing between the maximum value and the minimum value.

  In the omnidirectional antenna in this embodiment, the total length of the U-shaped slot is about half of the total length (λ) of the conventional loop type omnidirectional antenna, so two slots are arranged in one metal tube. Thus, one metal tube can resonate at two frequencies. Thereby, in the omnidirectional array antenna, the space constituting the antenna can be reduced, and the range of options for the element spacing can be expanded.

  6A and 6B are diagrams showing the characteristics of the 1.9 GHz band of the omnidirectional array antenna of FIG. 5, where FIG. 6A shows the vertical in-plane gain, and FIG. 6B shows the horizontal plane directivity. FIG. 7 is a diagram showing the characteristics of the antenna in the 2.56 GHz band, where (a) shows the vertical in-plane gain, and (b) shows the horizontal plane directivity. 6 and 7, the omnidirectional array antenna according to the present embodiment is characterized by an omnidirectional array antenna that uses 15 slots 2 for high frequency bands and 20 slots 3 for low frequency bands. Is shown.

  As shown in FIGS. 6A and 6B, the vertical in-plane gain shows a high gain at almost all angles θ at any frequency of 1.88 GHz, 1.9 GHz, and 1.92 GHz. In particular, the gain is approximately −20 to −0 dB at θ = −150 ° to −30 ° and 30 ° to 150 °. In addition, the directivity in the horizontal plane is almost omnidirectional at any frequency of 1.88 GHz, 1.9 GHz, and 1.92 GHz.

  Further, as shown in FIGS. 7A and 7B, with respect to the vertical in-plane gain, a high gain is obtained at almost all angles θ at any frequency of 2.54 GHz, 2.56 GHz, and 2.58 GHz. In particular, the gain is approximately −20 to −0 dB at θ = −150 ° to −30 ° and 30 ° to 150 °. Further, the directivity in the horizontal plane is almost omnidirectional at any frequency of 2.54 GHz, 2.56 GHz, and 2.58 GHz. Therefore, it can be seen that the omnidirectional array antenna of this embodiment has good vertical in-plane gain and horizontal omnidirectionality in both the high frequency band fH and the low frequency band fL.

  As described above, according to the present embodiment, the slots 2 and 3 formed in the conductive film 12 are U-shaped, and each total length is λ / 4 to λ / 2. And the metal pipe 4 is arrange | positioned so that a slot may be covered, and the length is (lambda) / 2 or less. Further, the length of each branch path of the microstrip lines 5 and 6 can be shortened by the open slot configuration. That is, two slots 2 and 3 are arranged in one metal tube 4 so that one metal tube 4 can resonate at two frequencies. Thereby, the space which comprises an antenna can be made small and size reduction of an omnidirectional antenna can be implement | achieved. In addition, when a plurality of omnidirectional antennas 100 are arranged in tandem to form an omnidirectional array antenna, a space can be formed between adjacent omnidirectional antennas. It becomes possible to arrange in a space, and thereby phase adjustment can be easily performed.

  FIG. 8 is a diagram schematically showing the configuration of an omnidirectional antenna according to a second embodiment of the present invention, where (a) is a perspective view and (b) is a cross section taken along line BB in (a). FIG. The omnidirectional antenna according to the second embodiment has a configuration in which a through hole is provided in the omnidirectional antenna according to the first embodiment. Since other configurations are basically the same as those of the omnidirectional antenna of FIG. 1, the description thereof will be omitted, and different parts will be described.

  In FIG. 8, in the omnidirectional antenna 200, through holes 71 are arranged on the dielectric substrate 1 along the microstrip line 5 on both sides of the microstrip line 5. The through hole 71 is filled with a conductor 72 such as solder integrally formed with the conductive film 12. On the microstrip line 5 side, adjacent conductors 72 are electrically connected by the electrode pattern 201. That is, on the microstrip line 5 side, two rows of pattern wirings 201 are formed on both sides of the microstrip line 5 so as to be parallel to the microstrip line. Through holes are also formed on both sides of the microstrip line 6 in the same manner, and the configuration thereof is basically the same as that of the through hole 71, so that the description thereof is omitted.

  In the present embodiment, the conductor 72 made of a conductive material such as solder is filled in the through hole 71, but the present invention is not limited to this, and the conductive film is formed on the inner peripheral surface of the through hole 71. It may be.

  FIG. 9 is a diagram comparing characteristics of an omnidirectional antenna in which a through hole is not provided in a dielectric substrate and an omnidirectional antenna in which a through hole is provided.

  An omnidirectional antenna having no through hole is almost omnidirectional in the 1.9 GHz band. On the other hand, in the omnidirectional antenna in which the through hole is formed, in addition to being almost omnidirectional in the 1.9 GHz band, the omnidirectionality in the 2.56 GHz band is improved. Therefore, it is possible to further improve the omnidirectionality of the two frequencies by providing a through hole in the omnidirectional antenna or the omnidirectional array antenna.

  10A and 10B are views for explaining a method of fixing the metal tube 4 in FIG. 8, wherein FIG. 10A is a plan view of the dielectric substrate 1, and FIG. 10B shows a state in which the metal tube is fixed to the dielectric substrate 1. .

  As shown in FIG. 10, the omnidirectional antenna 300 is provided on both side surfaces in the width direction of the dielectric substrate 1, engaging portions 313 and 315 that engage with one end surface of the metal tube 4, and the metal tube 4. Engaging portions 314 and 316 that engage with the other end surface of the first member. The engaging portions 313 and 314 are formed on one end face in the width direction of the dielectric substrate 1 and cooperate with each other to fix the metal tube 4 at a predetermined position. Further, the engaging portions 315 and 316 are formed on one end face in the width direction of the dielectric substrate 1, and cooperate with each other to fix the metal tube 4 at a predetermined position.

  In the present embodiment, the engaging portions 313, 314, 315, and 316 have a comb shape. Thereby, even when it is desired to change the fixing position of the metal tube 4 or when the length of the metal tube 4 is changed, the metal tube 4 can be securely fixed to the dielectric substrate 1.

  When the metal tube 4 is fixed to the dielectric substrate 1, the U-shaped slot 2 has the metal tube 4 in a state in which a part of the omnidirectional antenna 300 protrudes from the end surface of the metal tube 4 in a plan view. The entire U-shaped slot 3 is accommodated in the metal tube 4.

  In this embodiment, the end of the U-shaped slot 2 is arranged so as to protrude from the end surface of the metal tube 4 in a plan view of the omnidirectional antenna 100, but the present invention is not limited to this. In the plan view of the omnidirectional antenna 100, the entire U-shaped slot 2 and the entire U-shaped slot 3 may be accommodated in the metal tube 4.

  In the present embodiment, the engaging portions 313 and 314 are formed on one end surface in the width direction of the dielectric substrate 1, and the engaging portions 315 and 316 are formed on the other end surface in the width direction of the dielectric substrate 1. However, it is not limited to this. A pair of engagement portions that respectively engage with both end portions in the axial direction of the metal tube 4 may be formed on any one end surface in the width direction of the dielectric substrate 1.

  FIG. 11 is a diagram illustrating a modification of the omnidirectional array antenna of FIG. 5, (a) a first modification, (b) a second modification, and (c) a third modification.

  In FIG. 11A, the omnidirectional array antenna 400 includes a U-shaped slot 401 for another frequency band, for example, 900 MHz band, in addition to the omnidirectional antenna 100. The U-shaped slots 401 are arranged in tandem with the U-shaped slots 2 and 3, and are formed so that the opening side thereof faces the opening side of the U-shaped slot 3. At this time, the total length of the slot 401 is almost twice the total length of the slot 2, and the length of the metal tube 4 also becomes a large value according to the total length of the slot 401. Thereby, a small 3 frequency shared omnidirectional antenna can be constituted.

  Further, the omnidirectional array antenna of FIG. 5 is a omnidirectional antenna for two frequencies. However, the omnidirectional antenna is not limited to this, and as shown in FIG. 11B, for one frequency having a high frequency slot 501. An omnidirectional array antenna in which a plurality of omnidirectional antennas 500 are arranged may be used. In this case, the length of the metal tube 4 is designed to be, for example, λ / 2 or less.

  Further, in the omnidirectional array antenna of FIG. 5, the two adjacent metal tubes 4 are arranged at a constant interval, but as shown in FIG. 11C, the two adjacent metal tubes 4 have different intervals. (A ≠ b) may be arranged.

  FIG. 12 is a diagram illustrating a modification of the omnidirectional antenna of FIG.

  In FIG. 12, the U-shaped slots 602 and 603 of the omnidirectional antenna 600 are arranged side by side in the width direction of the dielectric substrate 1, and each open toward one opening side of the metal tube 604. Are arranged as follows. The U-shaped slot 602 is supplied with power from the microstrip line 605, and the U-shaped slot 603 is supplied with power from the microstrip line 606.

  FIG. 13 is a view showing a modification of the slots 2 and 3 in FIG. 1, wherein (a) shows a first modification, and (b) shows a second modification.

  The slots 2 and 3 in FIG. 1 are substantially U-shaped. However, the present invention is not limited to this, and for example, the slots 2 and 3 may be substantially spatula-shaped as shown in FIG. 13A or as shown in FIG. May be substantially U-shaped. That is, in each slot of this embodiment, it is only necessary that both ends of the slot have an open shape in plan view. This open shape is the shape of both ends of the slot formed by opening one portion of the annular slot. It is.

  14A and 14B are diagrams showing a modification of the microstrip line 5 in FIG. 1, wherein FIG. 14A shows a first modification, and FIG. 14B shows a second modification.

  The microstrip line 5 in FIG. 1 has a substantially L-shaped branch path, but is not limited thereto. The microstrip line 906 may have only the first line 915 extending from the main line of the microstrip line 5 toward the inside at a substantially right angle. In this case, when the third slot portion 23 and the first line 915 are projected on one plane, the third slot portion 23 is disposed so as to intersect the first line 915 at a substantially right angle. Thereby, the microstrip line 906 can have a simple configuration.

  The microstrip line 906 may have only the first line 916 extending from the main line of the microstrip line 5 to the inside at an elevation angle of approximately 45 °. In this case, when the third slot portion 23 and the first line 916 are projected on one plane, the third slot portion 23 is arranged to intersect the first line 916 at approximately 45 °. Accordingly, the configuration of the microstrip line 906 can be given a degree of freedom.

  Moreover, this embodiment shows an example of the omnidirectional antenna and the omnidirectional array antenna according to the present invention, and is not limited to this. The detailed configuration of the omnidirectional antenna and the omnidirectional array antenna in the present embodiment can be changed as appropriate without departing from the spirit of the present invention.

DESCRIPTION OF SYMBOLS 1 Dielectric board | substrate 2,3 U-shaped slot 4 Metal pipe 5,6 Microstrip line 12 Conductive film 21,31 1st slot part 22,32 2nd slot part 23,33 3rd slot part 51,61 1st Lines 52, 62 Second lines 53a, 53b Meander part 71 Through hole 100 Omnidirectional antenna 313, 314, 315, 316 Engagement part

Claims (10)

A dielectric substrate;
A conductive layer formed on one surface of the dielectric substrate;
A slot formed in the conductive layer, having both ends open in plan view and having a total length of λ / 4 to λ / 2;
A feeding path formed on the other surface of the dielectric substrate and extending to the inside of the slot when the slot is projected;
An omnidirectional antenna, characterized in that the metal ring is disposed so as to cover the slot and constitutes a parasitic element, and the length thereof is λ / 2 or less. A first slot that emits electromagnetic waves in the low frequency band fL and a second slot that emits electromagnetic waves in the high frequency band fH;
A first feeding path formed on the other surface of the dielectric substrate and extending to the inside of the first slot when the first slot is projected;
A second feeding path formed on the other surface of the dielectric substrate and extending to the inside of the second slot when the second slot is projected,
2. The omnidirectional antenna according to claim 1, wherein the metal ring is disposed so as to cover the first slot and the second slot, and has a length of λ / 2 or less of a high frequency band fH. .   The omnidirectional antenna according to claim 2, wherein the first feeding path and the second feeding path are arranged at both ends of the dielectric substrate.   The omnidirectional antenna according to any one of claims 1 to 3, wherein an open shape of the slot is disposed on an opening side of the metal ring.   5. The omnidirectional antenna according to claim 1, wherein the dielectric substrate is long and the width dimension of the dielectric substrate is approximately λ / 5.   The omnidirectional antenna according to any one of claims 1 to 5, wherein a plurality of through holes are formed in the dielectric substrate along the feeding path.   7. The device according to claim 1, further comprising a pair of comb-like engagement portions that are provided on an end surface of the dielectric substrate and respectively engage with both axial end portions of the metal ring. The omnidirectional antenna described.   An omnidirectional array antenna configured by arranging a plurality of omnidirectional antennas according to claim 1 or a plurality of omnidirectional antennas according to claim 2 in a tandem arrangement.   9. The feeding path of one omnidirectional antenna and the feeding path of another omnidirectional antenna are connected via a meander between two adjacent omnidirectional antennas. Omni-directional array antenna.   The omnidirectional antenna according to claim 8 or 9, wherein the omnidirectional antenna according to claim 1 and the omnidirectional antenna according to claim 2 are alternately arranged in tandem to constitute a three-frequency shared antenna.

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