JP2008042375A - Strip line feed circuit and triplate type plane sector beam antenna provided with the feed circuit - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a strip line feed circuit capable of surely laying a strip line even when the laying space of the strip line is limited, and a triplate type plane sector beam antenna. <P>SOLUTION: Output impedance converters 23a and 23d for supplying reference output power to antenna elements 14a and 14d and an impedance converter 22a for distribution are directly connected to each other, and output impedance converters 23b, 23c, 23e and 23f for supplying the other output power to antenna elements 14b, 14c, 14e and 14f, are connected via a meander shape line 20 to the other impedance converters 22b and 22d for distribution, respectively. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a stripline feed circuit that distributes input power supplied from the outside to a plurality of output powers by a parallel feed system and supplies the output power to the outside, and a triplate type planar sector beam antenna having the feed circuit. The present invention relates to a stripline feed circuit and a triplate type planar sector beam antenna suitable as a power distributor composed of a strip line of a microwave band and a millimeter wave band and a feed circuit of a sector beam antenna.

  In a conventional triplate type planar sector beam antenna (hereinafter also referred to as sector beam antenna), a plurality of antenna elements are arranged by either a series feeding method or a parallel feeding method by arranging a beam radiation surface along a vertical direction. When a power is supplied to the beam, a sector beam is radiated in a horizontal direction (in a horizontal plane) from each of the antenna elements arranged on the beam radiation surface. In this case, a parallel power feeding method with a small frequency characteristic is adopted in the broadband sector beam antenna.

  As shown in FIG. 5, the sector beam antenna 10 by the parallel feeding method includes a first ground conductor plate 11 made of metal (for example, aluminum) and a dielectric plate having a dielectric constant close to air (for example, foam made of polyester). A first dielectric plate 12a composed of a sheet), a printed circuit board 15 composed of a dielectric plate such as polytetrafluoroethylene or polyimide, and a dielectric plate identical to the first dielectric plate 12a. The second dielectric plate 12b and a metal (for example, aluminum) second ground conductor plate 16 in which a plurality of slots 17 are formed are stacked in this order. As shown in FIG. 6, a plurality of antenna elements 14 (six antenna elements 14 a to 14 f in FIG. 6) and a stripline power supply circuit 30 that supplies power to each of the antenna elements 14 a to 14 f. 32 and are respectively formed. In this case, when the second ground conductor plate 16 is viewed along the stacking direction (vertical direction shown in FIG. 5), the antenna elements 14a to 14f are arranged so as to be accommodated in the slot 17, and the stripline feed circuit 30 and 32 are arranged so as to be generally accommodated between the slots 17.

  Here, as shown in FIGS. 6 and 7, the stripline power supply circuit 30 includes a stripline formed on the printed circuit board 15 (see FIG. 5), and includes an input port 21 to which input power is supplied. It has a feed line 13 provided and output impedance converters 23a to 23c which are output ports for supplying output power to the antenna elements 14a to 14c (see Non-Patent Documents 1 to 5).

  In the stripline power supply circuit 30, the distribution impedance converters 22c and 22d are T-branched from the power supply line 13, and the distribution impedance converters 22a and 22b are further T-branched from the distribution impedance converter 22c. In other words, the distribution impedance converters 22a to 22d form a parallel feed line connected in a tournament shape by a T branch with respect to the feed line 13.

  The distribution impedance converter 22a is connected to the antenna element 14a via the impedance matching constant impedance line 24 and the output impedance converter 23a. The distribution impedance converter 22b includes the meander-shaped line 20, the constant impedance line, and the like. 24 and the output impedance converter 23b are connected to the antenna element 14b, and the distribution impedance converter 22d is connected to the antenna element 14c via the constant impedance line 24, the meander line 20 and the output impedance converter 23c. Yes.

  On the other hand, the stripline power supply circuit 32 also has a power supply line 13 and output impedance converters 23d to 23f, similarly to the stripline power supply circuit 30, and the distribution impedance converter 22a in the stripline power supply circuit 32 includes: The distribution impedance converter 22b is connected to the antenna element 14e via the meander-shaped line 20, the constant impedance line 24, and the output impedance converter 23e, and is connected to the antenna element 14d via the constant impedance line 24 and the output impedance converter 23d. The distributed impedance converter 22d is connected to the antenna element 14f via the constant impedance line 24, the meander-shaped line 20, and the output impedance converter 23f.

  The impedances of the feeder line 13, the distribution impedance converters 22a to 22d, the meandering line 20, the constant impedance line 24, and the output impedance converters 23a to 23f are the line width of each strip line and the first ground conductor plate 11. And the distance between the strip lines (the thickness of the first dielectric plate 12a and the printed board 15) and the distance between the second ground conductor plate 16 and the strip lines (the thickness of the second dielectric plate 12b). It is determined appropriately according to the specifications of the stripline power supply circuits 30 and 32.

  Here, when input power is supplied to the input ports 21 of the stripline power supply circuits 30 and 32 from the outside, each of the distribution impedance converters 22a to 22d distributes the input power at a predetermined distribution ratio to obtain a desired amplitude. To generate a plurality of output powers. Each meander-shaped line 20 adjusts the phase of each output power to a desired phase by adjusting the line length. Each output impedance converter 23a-23f supplies the output power adjusted to a desired amplitude and phase to the antenna elements 14a-14f. As a result, if the sector beam antenna 10 is disposed vertically, it is possible to radiate the sector beam into the horizontal plane from the antenna elements 14a to 14f via the slot 17.

Kai Fong Lee, Wei Chen, “Advanceds in Microstrip and Printed Antennas” (USA), John Wiley & Sons, 1997, p. 144-147 Haneishi, “Latest planar antenna technology”, General Technology Center, 1993, p. 297-309 A. Balanis, “Antenna Theory analysis and design” (USA), John Wiley & Sons, 1997, p. 772-774 R. J. et al. Mailloux, J.M. F. Mclvenna, N.M. P. Kernweis, “Microstrip Array Technology”, IEEE Trans. Antennas Propagat. (USA), January 1981, Vol. AP-29, no. 1, p. 25-27 JR James, PS Hall, “Handbook of Microstrip Antenna”, IEE, 1989, p. 850-852

  In the above parallel power feeding method, it is necessary to distribute input power to generate output power, and to adjust this output power to a desired phase. Therefore, it is necessary to secure some space for routing the strip line as a power feeding line. It is necessary to keep.

  However, in the sector beam antenna 10 shown in FIGS. 5 to 7, it is difficult to secure such a routing space between the slots 17 for the following reasons (1) to (3).

  (1) When the spacing between the antenna elements 14a to 14f is changed in the vertical direction (the vertical direction in FIGS. 6 and 7), the directivity of the sector beam radiated from the slot 17 in the vertical direction (in the vertical plane) changes. Therefore, it is difficult to widen the routing space in the vertical direction by widening the vertical interval between the antenna elements 14a to 14f.

  (2) If the vertical dimension of the slot 17 is reduced, the aperture efficiency of the sector beam is reduced and the cross polarization is also increased, so that the characteristics of the sector beam are deteriorated. Therefore, it is difficult to reduce the vertical dimension of the slot 17 and expand the routing space in the vertical direction.

  (3) When the feed line 13 protrudes into the slot 17, unnecessary radiation is generated from the feed line 13, and the directivity pattern of the sector beam is disturbed, so that impedance deviation occurs between the antenna elements 14 a to 14 f. To do. Therefore, it is difficult to expand the routing space in the vertical direction so that the strip line power supply circuits 30 and 32 protrude into the slot 17.

  Furthermore, there is a concern about the inconvenience shown in the following (4) due to the limited routing space.

  (4) When the distribution impedance converters 22a to 22d are narrow, or when the distribution impedance converter 22a and the feed line 13 are narrow, coupling occurs between them. Deviation occurs in the amplitude and phase of power. Further, even when the routing space is limited, the line lengths of the output impedance converters 23a to 23f and the line lengths of the distribution impedance converters 22a to 22d are converted to the in-tube wavelength at a predetermined frequency. It is necessary to have a length of 4 wavelengths.

  The present invention has been made to solve the above-described problems, and in the parallel power feeding method, even if the space for the strip line serving as the power feeding line is limited, the strip line can be reliably routed. It is an object of the present invention to provide a stripline feed circuit and a triplate type planar sector beam antenna having the stripline feed circuit.

  For the sake of easy understanding, this item is described with reference numerals in the attached drawings. Therefore, the contents described in this item are not construed as being limited to those given the reference numerals.

  The stripline power feeding circuits 40 and 42 according to the present invention include one input port 21, a plurality of distribution impedance converters 22a to 22d connected to the input port 21 by a T-branch in a tournament shape, and a meander shape. The line 20 and a plurality of output impedance converters 23a to 23f are provided, and input power supplied to the input port 21 from the outside is distributed to a plurality of output powers by the distribution impedance converters 22a to 22d. In the stripline feed circuits 40 and 42, the phase of each output power is adjusted by the meander-shaped line 20 and the output power is supplied to the outside from the output impedance converters 23a to 23f. Among the converters 23a to 23f, one output impedance converter 23a, 23d One of the distribution impedance converters 22a to 22d is directly connected to one distribution impedance converter 22a, and the other output impedance converters 23b, 23c, 23e, and 23f are connected to the other through the meander-shaped line 20. The distribution impedance converters 22b and 22d are connected to the output impedance converters 23a and 23d, respectively, and reference output power serving as a reference for the output power is output to the meander-shaped line 20. The phase of other output power is adjusted so as to be in phase with the reference output power, and each of the distribution impedance converters 22a to 22d has an amplitude of the other output power so as to have the same amplitude as the reference output power. It is characterized by adjusting.

  According to this configuration, the output impedance converters 23a and 23d that output the reference output power are directly connected to the distribution impedance converter 22a, and the other output impedance converters 23b, 23c, 23e, and 23f are connected to the meander. The other distribution impedance converters 22b and 22d are connected via the shape line 20, respectively.

  This eliminates the need for the constant impedance line 24 in the conventional stripline power supply circuits 30 and 32 (see FIGS. 6 and 7), and the line length of the stripline from the input port 21 to the output impedance converters 23a to 23f. Is shortened, and discontinuous points in the strip line (connection points in the strip line) are reduced. As a result, the stripline routing space can be afforded and the coupling between the striplines is suppressed, so that the deviation of the amplitude and phase of the output power can be reduced.

  Therefore, according to the present invention, the stripline can be reliably routed even if the stripline routing space is limited. In addition, since deviations in the amplitude and phase of the output power are reduced, it is possible to reliably output output power having the same amplitude and the same phase to the output impedance converters 23a to 23f.

  The triplate type planar sector beam antenna 50 according to the present invention includes a first ground conductor plate 11, a first dielectric plate 12a, the above-described stripline power supply circuits 40 and 42, and the stripline power supply circuits 40 and 42. Printed circuit board 15 on which a plurality of antenna elements 14 and 14a to 14f respectively connected to the output impedance converters 23a to 23f are arranged, a second dielectric plate 12b, and a first slot in which a plurality of slots 17 are formed. The antenna elements 14 and 14a to 14f are disposed in the slots 17 when the second ground conductor plate 16 is viewed along the stacking direction. , Between the slots 17, the input ports 21 of the stripline power supply circuits 40, 42, the distribution impedance converters 22 a to 22 d, Wherein the under-shaped line 20 and the part of the output impedance converter 23a~23f are arranged.

  According to this configuration, the stripline can be reliably routed even in a place where the stripline routing space is limited, such as between the slots 17. Further, as described above, since the deviation of the amplitude and phase of the output power is reduced, the output power having the same amplitude and the same phase is surely output to the output impedance converters 23a to 23f, and the antenna elements 14, Variations in the directivity pattern of the sector beam radiated to the outside through the slot 17 from 14a to 14f can be suppressed.

  According to the present invention, the output impedance converter for outputting the reference output power and the distribution impedance converter are directly connected, and the other output impedance converter is connected to the other distribution impedance converter via the meander-shaped line. Since each connection is made, the constant impedance line 24 in the conventional stripline power supply circuits 30 and 32 (see FIGS. 6 and 7) is unnecessary, and the stripline line from the input port to the output impedance converter is eliminated. As the length is shortened, discontinuities in the stripline are reduced. As a result, the stripline routing space can be afforded and the coupling between the striplines is suppressed, so that the deviation of the amplitude and phase of the output power can be reduced. Therefore, in the present invention, the stripline can be reliably routed even if the stripline routing space is limited.

  A preferred embodiment of a stripline feed circuit according to the present invention and a triplate type planar sector beam antenna having the stripline feed circuit will be described below and described with reference to the accompanying drawings.

  When the stripline feed circuits 40 and 42 and the triplate type planar sector beam antenna (hereinafter also referred to as sector beam antenna) 50 according to the present embodiment are described with reference to FIGS. The same components as those of the feeder circuits 30 and 32 (see FIGS. 6 and 7) and the sector beam antenna 10 (see FIG. 5) will be described with the same reference numerals.

  As shown in FIGS. 1 and 2, the stripline power supply circuit 40 according to the present embodiment directly connects the distribution impedance converter 22a and the output impedance converter 23a, and connects the distribution impedance converter 22b to the meander-shaped line. 20 is connected to the output impedance converter 23b via the line 20, and the distribution impedance converter 22d is connected to the output impedance converter 23c via the meander-shaped line 20, so that the stripline power feeding circuit 30 according to the prior art ( 6 and 7).

  Further, the stripline power supply circuit 42 according to the present embodiment directly connects the distribution impedance converter 22a and the output impedance converter 23d, and connects the distribution impedance converter 22b via the meander-shaped line 20 to the output impedance converter. 23e, and the distribution impedance converter 22d is connected to the output impedance converter 23f via the meander-shaped line 20, and the stripline power supply circuit 32 according to the prior art (see FIGS. 6 and 7). Is different.

  That is, in the stripline power supply circuits 40 and 42, one output impedance converter 23a and 23d is directly connected to one distribution impedance converter 22a, and the other output impedance converters 23b, 23c, 23e, and 23f are A configuration in which the constant impedance line 24 connected to the other distribution impedance converters 22b and 22d via the meander-shaped line 20 and constituting the stripline power supply circuits 30 and 32 (see FIGS. 6 and 7) is omitted. It has become. In this case, in the strip line feed circuits 40 and 42, impedance matching between the converters is performed by appropriately setting the line widths of the strip lines constituting the output impedance converters 23a to 23f and the distribution impedance converters 22a to 22d. Therefore, the constant impedance line 24 is omitted.

  Furthermore, the sector beam antenna 50 according to the present embodiment is different from the sector beam antenna 10 according to the prior art (see FIG. 5) in that it has stripline feed circuits 40 and 42 instead of the stripline feed circuits 30 and 32. Different.

  Next, operations and effects of the stripline feed circuits 40 and 42 and the sector beam antenna 50 according to the present embodiment will be described with reference to FIGS.

  First, in a state where the sector beam antenna 50 is arranged vertically {in a state where the sector beam antenna 50 is erected so that the surface of the second ground conductor plate 16 (see FIG. 5) is along the vertical direction}, the stripline feed circuit 40 is provided. , 42 are supplied with input power respectively.

  The distribution impedance converters 22a to 22d in the strip line power supply circuits 40 and 42 distribute the input power supplied to the input port 21 of the power supply line 13 into a plurality of output powers having a predetermined amplitude.

  In this case, in the stripline power feeding circuits 40 and 42, the output power (reference output power) supplied to the antenna elements 14a and 14d from the output impedance converters 23a and 23d directly connected to the distribution impedance converter 22a Output impedance converters 23b, 23c, 23e, and 23f are used as reference power for output power (other output power) supplied to the antenna elements 14b, 14c, 14e, and 14f, and the reference output power and other output power Are adjusted to have the same amplitude and the same phase using the distribution impedance converters 22a to 22d and the meander-shaped line 20 to adjust the amplitude and phase of the other output power.

  That is, the distribution impedance converters 22a to 22d are configured such that the reference output power in the output impedance converters 23a and 23d and the other output powers in the output impedance converters 23b, 23c, 23e, and 23f have the same amplitude. The amplitude of the other output power is adjusted according to a predetermined distribution ratio. On the other hand, by adjusting the length of each meander-shaped line 20, the reference output power in the output impedance converters 23a and 23d and the other output powers in the output impedance converters 23b, 23c, 23e, and 23f are in phase. The phase of the other output power is adjusted so that

  As a result, output powers having the same amplitude and the same phase are supplied from the output impedance converters 23a to 23f to the antenna elements 14a to 14f, respectively. As a result, the horizontal direction (horizontal plane) from the antenna elements 14a to 14f via the slots 17 (Inside) a sector beam is emitted.

  FIG. 3A is a graph (comparative example) showing a directivity pattern in a horizontal plane of a sector beam radiated from the sector beam antenna 10 (see FIG. 5) according to the prior art, and FIG. 3B is a sector according to the present embodiment. It is a graph (Example) which shows the directivity pattern in the horizontal surface of the sector beam radiated | emitted from the beam antenna 50. FIG.

  The angle on the horizontal axis indicates the angle (azimuth angle) from the central axis 28 (see FIGS. 1 and 6) of the slot 17 toward the antenna elements 14b and 14e. Further, f / fc represents a ratio between the center frequency fc of the sector beam and an arbitrary frequency f. Further, the characteristics of the broken line in FIGS. 3A and 3B indicate the upper limit of the directivity pattern of the sector beam defined by ETSI (European Telecommunication Standards Institute).

  3A and 3B, if the usable range of the sector beam radiated from the slot 17 is set to −3 [dB] or more and an azimuth angle range of −45 [°] to +45 [°], FIG. In the comparative example, when f / fc is changed, the range of the azimuth angle is changed. This is because strip lines (feed line 13, distribution impedance converters 22a to 22d, meander) constituting strip line feed circuits 30 and 32 (see FIGS. 6 and 7) within a limited space between the slots 17 are provided. By routing the shape line 20, the constant impedance line 24, and the output impedance converters 23a to 23f), coupling occurs between the strip lines, resulting in a deviation in the amplitude and phase of the output power. This is because the directivity pattern is disturbed.

  On the other hand, in the embodiment of FIG. 3B, even if f / fc is changed, the range of the azimuth angle in the directivity pattern of the sector beam hardly changes. This is because the stripline power supply circuits 40 and 42 (see FIGS. 1 and 2) according to the present embodiment have a configuration in which the constant impedance line 24 (see FIGS. 6 and 7) is omitted. This is because the line length of the strip line from the impedance converters 23a to 23d is shortened, so that a space for the strip line can be provided, and discontinuous portions of the strip line are reduced. That is, by providing a margin in the routing space and reducing the discontinuous portions, it is possible to suppress the coupling generated between the strip lines, so that the antenna elements 14a to 14f have the same amplitude and In-phase output power can be reliably supplied. As a result, a sector beam having a desired directivity pattern can be emitted from the slot 17 into the horizontal plane.

  FIG. 4 is a graph showing the relationship between VSWR (voltage standing wave ratio) and f / fc in the comparative example and the example. If the region where the value of VSWR is 1.55 or less is used, it can be understood that this example has a wider band than the comparative example.

  Thus, according to the present embodiment, the output impedance converters 23a and 23d that output the reference output power and the distribution impedance converter 22a are directly connected, and the other output impedance converters 23b, 23c, 23e, and 23f are connected. Are connected to other distribution impedance converters 22b and 22d through meander-shaped lines 20, respectively.

  As a result, the constant impedance line 24 in the conventional stripline power supply circuits 30 and 32 (see FIGS. 6 and 7) becomes unnecessary, and the stripline from the input port 21 to the output impedance converters 23a to 23d is eliminated. As the line length is shortened, discontinuous portions (strip line connection points) in the strip line are reduced. As a result, the strip line routing space can be afforded, and the coupling between the strip lines is suppressed, so that the deviation of the amplitude and phase of the output power can be reduced.

  Therefore, according to this embodiment, even if the stripline routing space is limited, the stripline can be reliably routed. Further, since the deviation of the amplitude and phase of the output power is reduced, it is possible to reliably output the output power having the same amplitude and the same phase to the output impedance converters 23a to 23f.

  Furthermore, it is possible to reliably route the stripline even in a place where the stripline routing space is limited, such as between the slots 17. Furthermore, since the deviation of the amplitude and phase of the output power is reduced, if the output power having the same amplitude and the same phase is supplied from the output impedance converters 23a to 23f to the antenna elements 14a to 14f, the antenna elements 14a to 14f Variation in the directivity pattern due to the frequency in the sector beam radiated into the horizontal plane through the slot 17 can be suppressed.

  In the above description, the embodiment in which the stripline power supply circuits 40 and 42 are applied to the sector beam antenna 50 has been described. However, the stripline power supply circuits 40 and 42 are applied to power dividers in the microwave band and the millimeter wave band. Of course, the above-described effects can be obtained.

  The stripline feed circuit and the triplate type planar sector beam antenna having the feed circuit according to the present invention are not limited to the above-described embodiments, and various configurations can be adopted without departing from the gist of the present invention. It is.

It is a top view of the stripline electric power feeding circuit as a part of sector beam antenna concerning this embodiment. It is the top view to which a part of stripline electric power feeding circuit of FIG. 1 was expanded. FIG. 3A is a graph showing the directivity pattern of the sector beam of the comparative example, and FIG. 3B is a graph showing the directivity pattern of the sector beam of the example. It is a graph which shows the relationship between VSWR and f / fc of an Example and a comparative example. It is a disassembled perspective view of the sector beam antenna based on a prior art. FIG. 6 is a plan view of a stripline feed circuit as a part of the sector beam antenna of FIG. 5. It is the top view to which a part of stripline electric power feeding circuit of FIG. 6 was expanded.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10, 50 ... Sector beam antenna 11 ... 1st earth conductor board 12a ... 1st dielectric board 12b ... 2nd dielectric board 13 ... Feeding line 14, 14a-14f ... Antenna element 15 ... Printed circuit board 16 ... 2nd earth conductor Plate 17 ... Slot 20 ... Meander-shaped line 21 ... Input ports 22a-22d ... Distributing impedance converters 23a-23f ... Output impedance converter 24 ... Constant impedance line 28 ... Central axes 30, 32, 40, 42 ... Strip line feed circuit

Claims (2)

One input port, a plurality of distribution impedance converters connected to the input port in a tournament by a T-branch, a meander-shaped line, and a plurality of output impedance converters; The input power supplied to the port is distributed to a plurality of output powers by each distribution impedance converter, the phase of each output power is adjusted by the meander-shaped line, and each output power is converted to each output impedance. In the stripline power supply circuit that supplies externally from the converter,
One of the output impedance converters is directly connected to one of the distribution impedance converters, and the other output impedance converter is of the meander shape. Connected to other distribution impedance converters via lines,
The first output impedance converter outputs a reference output power serving as a reference for each output power, and the meander line changes the phase of the other output power so as to be in phase with the reference output power. Adjust
Each of the distribution impedance converters adjusts the amplitude of the other output power so as to have the same amplitude as the reference output power. A printed circuit board comprising: a first ground conductor plate; a first dielectric plate; and a stripline feed circuit according to claim 1 and a plurality of antenna elements respectively connected to the output impedance converters of the stripline feed circuit. A substrate, a second dielectric plate, and a second ground conductor plate in which a plurality of slots are formed are stacked in this order,
When the second ground conductor plate is viewed along the stacking direction, the antenna elements are arranged in the slots, and the input ports of the stripline feed circuit and the distribution ports are arranged between the slots. A triplate type planar sector beam antenna, wherein an impedance converter, a meander line, and a part of each of the output impedance converters are arranged.

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