JP2006128898A - Antenna device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide the antenna device of a patch antenna structure which has a sheet-metal made radiation conductor made of a sheet metal and is promotably miniaturized. <P>SOLUTION: The sheet-metal patch antenna is provided with a radiation conductor plate 1 formed of a metallic plate having an external shape of almost round or almost polygon, and an opening 1a at a center position; a printed board 4 having a ground conductor layer 5 formed oppositely to the radiation conductor plate 1 with a predetermined distance; a plurality of mounting legs 2 for supporting the radiation conductor plate 1; and a power feeding terminal 3 for feeding power to the radiation conductor plate 1. In this antenna, each of the mounting legs 2 is formed of a metal piece protruding toward the printed board 4 side using the inner periphery of the radiation conductor plate 1 as a base end, and the tip of each of the mounting legs 2 is fixed on the printed board 4 at a portion not conductive to the ground conductor layer 5. With this configuration, since the mounting legs 2 each operate as an inductor, resonant frequency is low, and the metal piece continuing to the radiation conductor plate 1 is folded to form each of the mounting legs 2 and the power feeding terminal 3, thereby facilitating manufacturing the device. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to an antenna device having a patch antenna structure in which a radiating conductor plate is a metal flat plate.

  An antenna device in which the radiation conductor plate is a metal flat plate has an advantage that it can be manufactured at a lower cost than a normal patch antenna configured by patterning a radiation conductor on a dielectric substrate. In particular, in the configuration abbreviated as a sheet metal patch antenna, a feed plate that feeds power to the radiation conductor plate and a plurality of mounting legs that support the radiation conductor plate are cut and raised pieces of a metal flat plate including the radiation conductor plate. Therefore, the manufacturing cost can be greatly reduced and the required mechanical strength can be easily ensured. Therefore, high practicality suitable as a small vehicle-mounted antenna is expected (for example, Patent Document 1). reference).

  FIG. 6 is a plan view showing such a conventional sheet metal patch antenna, and FIG. 7 is a sectional view taken along line VII-VII in FIG. In these drawings, the antenna device (sheet metal patch antenna) has a radiating conductor plate 11 made of a metal plate having a circular outer shape and having an opening 11a at the center, and an inner peripheral edge of the radiating conductor plate 11 (periphery of the opening 11a). A plurality of mounting legs 12 projecting downward from the base end, a feed terminal 13 projecting downward from a predetermined position in the radiation conductor plate 11, and the radiation conductor plate 11 are held via the mounting legs 12 and the feed terminal 13. And a grounding conductor layer 15 such as a copper foil formed on almost the entire upper surface of the printed board 14 is opposed to the radiation conductor plate 11 with a predetermined interval. . Also, on the lower surface of the printed circuit board 14, a plurality of lands 16 that are conducted to the ground conductor layer 15 through the via holes 14 a and power feeding lands 17 that are not conducted to the ground conductor layer 15 are patterned. Yes. The radiation conductor plate 11, each mounting leg 12, and the power supply terminal 13 are formed by pressing a single metal plate.

As shown in FIG. 7, since the tip end (lower end) of the mounting leg 12 penetrates the via hole 14a of the printed circuit board 14 and is soldered to the land 16, each mounting leg 12 mechanically connects the radiating conductor plate 11. In addition to being supported by this, it operates as a short-circuited terminal conducted to the ground conductor layer 15. The front end (lower end) of the power supply terminal 13 is soldered together with the inner conductor of the coaxial cable (not shown) at the land 17, and a predetermined high-frequency signal is supplied to the radiation conductor plate 11 through the power supply terminal 13. It has become so. Since the short-circuit terminal (mounting leg 12) is disposed on the inner peripheral edge of the radiation conductor plate 11 in this way, the power feeding terminal 13 can be disposed outside the opening 11a. Design that secures the required length becomes easy.
JP-A-2004-48364 (page 3-4, FIG. 3)

  By the way, in the case of a configuration in which a plurality of mounting legs 12 that mechanically support the radiating conductor plate 11 are electrically connected to the ground conductor layer 15 as in the conventional antenna device (sheet metal patch antenna) described above, Since the potential at the proximal end is substantially zero, the path length of the high-frequency current flowing through the radiation conductor plate 11 cannot be increased by the mounting legs 12. Therefore, such a conventional antenna device has a problem that it is difficult to increase the resonance length to lower the resonance frequency, and it is difficult to promote downsizing.

  The present invention has been made in view of the actual situation of the prior art, and an object of the present invention is to provide an antenna device having a patch antenna structure that has a radiating conductor plate made of sheet metal and that can be easily reduced in size. is there.

  In order to achieve the above object, in the antenna device of the present invention, there is provided a radiating conductor plate made of a metal flat plate having a substantially circular shape or a substantially regular polygon and having an opening in the center, and a predetermined distance from the radiating conductor plate. And a plurality of mounting legs made of metal pieces projecting toward the board with the inner periphery of the radiation conductor plate as a base end, and tips of the plurality of mounting legs. The radiating conductor plate is held on the substrate via the plurality of mounting legs by fixing the portion to the substrate at a location where it is not electrically connected to the ground conductor layer.

  In this way, when the plurality of mounting legs protruding from the inner periphery of the radiating conductor plate to the board side are fixed to the board in a non-conductive state with respect to the ground conductor layer, each mounting which operates as an inductor during power feeding Since the potential of the leg does not become zero, the path length of the high-frequency current is increased by the mounting leg, and the resonance frequency is lowered. Therefore, the antenna device can be easily reduced in size, and the antenna device can be manufactured at low cost and the required mechanical strength can be easily ensured because the radiation conductor plate and the mounting legs are made of sheet metal.

  In the above configuration, a power supply terminal for supplying power to the radiation conductor plate is provided, and each of the power supply terminal and the plurality of mounting legs folds back a metal piece continuous to the radiation conductor plate to the substrate side. Is preferably formed by pressing a single metal plate to collectively form the radiation conductor plate, each mounting leg, and the power supply terminal. . In this case, if the inner periphery of the radiation conductor plate exists between the base end of the attachment leg and the opening, a part of the radiation conductor plate is cut and raised to form each attachment leg. Therefore, it is easy to design to secure a required length for each mounting leg by positioning the power supply terminal in the opening.

  Further, in the above configuration, when a plurality of lands that are non-conductive with the ground conductor layer are patterned on the substrate, and the tips of the plurality of mounting legs are soldered to the lands, Can be easily and reliably fixed to the substrate, which is preferable because the assemblability can be improved.

  In the antenna device of the present invention, a plurality of mounting legs protruding from the inner peripheral portion of the radiation conductor plate to the substrate side are fixed to the substrate in a non-conductive state with respect to the ground conductor layer. The resonance frequency is increased by the legs, and miniaturization is facilitated. In addition, since the radiation conductor plate and each mounting leg are made of sheet metal, the antenna device can be manufactured at low cost and required mechanical strength can be easily ensured.

  1 is a plan view of an antenna device (sheet metal patch antenna) according to a first embodiment of the present invention, and FIG. 2 is taken along line II-II in FIG. It is sectional drawing.

  The antenna apparatus shown in these drawings includes a radiating conductor plate 1 made of a metal plate having a square shape with four corners cut out and having an opening 1a at the center, and an inner peripheral edge of the radiating conductor plate 1 (periphery of the opening 1a). ) As base ends, four attachment legs 2 projecting downward, power supply terminals 3 projecting downward from the distal end of the projecting piece 1b extending from the radiation conductor plate 1 to a predetermined position in the opening 1a, and each mounting And a printed circuit board 4 holding the radiating conductor plate 1 via the legs 2 and the power supply terminals 3, and a grounding conductor layer 5 such as a copper foil formed on almost the entire upper surface of the printed circuit board 4. It faces the radiation conductor plate 1 with a gap of. Also, on the lower surface of the printed circuit board 4, the four lands 6 to which the tip portions (lower end portions) of the four mounting legs 2 are soldered and the tip portions (lower end portions) of the power supply terminals 3 are soldered. A pattern is formed with the power supply land 7. These lands 6 and 7 are not electrically connected to the ground conductor layer 5, and each land 6 is electrically isolated, and an inner conductor of a coaxial cable (not shown) is soldered to the lands 7. The printed circuit board 4 is also provided with a plurality of through holes 4a for penetrating the distal ends of the mounting legs 2 and the distal ends of the power supply terminals 3.

  Note that the radiation conductor plate 1, each mounting leg 2, and the power supply terminal 3 of this antenna device are formed by pressing a single metal plate. That is, each of the mounting legs 2 and the power supply terminal 3 is formed by folding a metal piece continuous with the radiation conductor plate 1 toward the printed circuit board 4.

  In the antenna device having such a configuration, the mounting legs 2 and the power supply terminals 3 extending from the radiation conductor plate 1 are soldered to the lands 6 and 7 of the printed circuit board 4, respectively. The radiation conductor plate 1 is securely held by the printed circuit board 4 via Further, two corners of the radiating conductor plate 1 are large cutouts 1c that function as degenerate separation elements. Therefore, by supplying a predetermined high-frequency signal via the feed terminal 3 to the feed point of the radiating conductor plate 1 facing the ground conductor layer 5 with a predetermined interval, the antenna device is a circularly polarized patch. It can be operated as an antenna.

  As described above, in the antenna device according to this embodiment, the plurality of mounting legs 2 protruding downward from the inner peripheral edge of the radiation conductor plate 1 are soldered to the printed circuit board 4 in a non-conductive state with the ground conductor layer 5. Therefore, the potential of each mounting leg 2 that operates as an inductor during power feeding does not become zero, and therefore the path length of the high-frequency current is increased by the mounting leg 2 and the resonance frequency is lowered. Therefore, this antenna device is a sheet metal patch antenna that facilitates miniaturization. In addition, this antenna device can press-process a single metal plate to form the radiation conductor plate 1, each mounting leg 2, and the power feeding terminal 3 together, and solder each mounting leg 2 and the power feeding terminal 3. Since the lands 6 and 7 are formed on the printed circuit board 4 in advance and are easy to assemble, the lands 6 and 7 can be manufactured at a very low cost and required mechanical strength can be easily secured.

  3 is a plan view of an antenna device (sheet metal patch antenna) according to a second embodiment of the present invention, FIG. 4 is a sectional view taken along line IV-IV in FIG. 3, and FIG. 5 is a development of the sheet metal portion of the antenna device. In the figure, parts corresponding to those in FIGS. 1 and 2 are denoted by the same reference numerals, and redundant description is omitted.

  The antenna device shown in FIGS. 3 and 4 is greatly different from the first embodiment described above in that the inner peripheral portion of the radiation conductor plate 1 is interposed between the base end of each mounting leg 2 and the opening 1a. The other configurations are basically the same. That is, in this antenna device, as shown in FIG. 5, each mounting leg 2 is made of a metal piece obtained by cutting and raising a part of the radiating conductor plate 1, and the base end side of these mounting legs 2 (position indicated by a one-dot chain line) ) Is folded substantially at a right angle. With such a configuration, it is easy to design the power supply terminals 3 within the openings 1a to ensure a required length for each mounting leg 2.

  In each of the above-described embodiments, the case where the outer shape of the radiation conductor plate made of a metal flat plate is a square shape has been described. However, the non-directionality in the in-plane direction (azimuth angle direction) of the radiation conductor plate can be ensured. The shape may also be Therefore, the outer shape of the radiation conductor plate may be substantially circular or substantially regular polygonal.

1 is a plan view of an antenna device according to a first embodiment of the present invention. It is sectional drawing which follows the II-II line of FIG. It is a top view of the antenna apparatus which concerns on the 2nd Example of this invention. It is sectional drawing which follows the IV-IV line of FIG. It is an expanded view of the sheet-metal part of this antenna apparatus. It is a top view of the sheet metal patch antenna which concerns on a prior art example. It is sectional drawing which follows the VII-VII line of FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Radiation conductor board 1a Opening 2 Mounting leg 3 Feeding terminal 4 Printed circuit board 5 Grounding conductor layer 6,7 land

Claims (4)

  A radiating conductor plate made of a metal flat plate having an outer shape of a substantially circular shape or a substantially regular polygon and having an opening in the center, a substrate on which a grounding conductor layer facing the radiating conductor plate with a predetermined interval is formed; A plurality of mounting legs made of metal pieces projecting toward the board with the inner peripheral part of the radiating conductor plate as a base end, and the board at a position where the tip ends of the plurality of mounting legs are not electrically connected to the ground conductor layer The antenna device is configured such that the radiating conductor plate is held on the substrate via the plurality of mounting legs by being fixed to the base plate.   2. The power supply terminal according to claim 1, further comprising a power supply terminal that supplies power to the radiation conductor plate, wherein each of the power supply terminal and the plurality of mounting legs has a metal piece continuous with the radiation conductor plate. An antenna device, wherein the antenna device is formed by folding back.   3. The antenna device according to claim 2, wherein an inner peripheral portion of the radiation conductor plate exists between a base end of the mounting leg and the opening.   4. The land according to claim 1, wherein a plurality of lands that are non-conductive with respect to the ground conductor layer are formed on the substrate, and tips of the mounting legs are soldered to the lands. An antenna device characterized by being attached.

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