JP3983224B2 - Patch antenna - Google Patents

Description

  The present invention relates to a patch antenna in which a radiating conductor provided on one surface of a dielectric substrate is fed by a feed pin, and more particularly to a patch antenna suitable for in-vehicle use.

  In recent years, the demand for patch antennas as dielectric antennas suitable for miniaturization and thinning has increased, and as an example, a patch antenna having a structure as shown in the cross-sectional view of FIG. 3 has been conventionally known (for example, Patent Document 1). reference). The patch antenna 1 shown in FIG. 1 is provided on a dielectric substrate 2 made of a dielectric material such as ceramic, a radiation conductor (patch electrode) 3 provided on the top surface of the dielectric substrate 2, and a bottom surface of the dielectric substrate 2. The grounding conductor (back electrode) 4 and the feeding pin 5 that penetrates the dielectric substrate 2 and is connected to the feeding point of the radiation conductor 3 are mainly configured.

  The dielectric substrate 2 is provided with a through hole 2a for inserting the power supply pin 5 at a position corresponding to the power supply point. The radiation conductor 3 and the ground conductor 4 are made of a highly conductive metal such as a copper foil, and are formed in a predetermined shape by etching or the like. The radiation conductor 3 is formed in an appropriate shape such as a rectangle or a circle, and when operated as a circularly polarized antenna, a degenerate separation element is loaded on the radiation conductor 3 as necessary. The ground conductor 4 is formed on almost the entire bottom surface of the dielectric substrate 2 except for the peripheral edge of the through hole 2a. The power feed pin 5 is a highly conductive metal pin, and its upper end (head) is soldered to the radiation conductor 3. The lower end portion of the power supply pin 5 is insulated from the ground conductor 4 and protrudes downward from the dielectric substrate 2 and is soldered to a land portion of a power supply circuit (not shown).

The resonance frequency of the patch antenna 1 schematically configured as described above is determined by the dielectric constant and thickness of the dielectric substrate 2 or the size and shape of the radiation conductor 3. Further, when the patch antenna 1 is manufactured, the through hole 2 a is provided in advance at a predetermined position (a position corresponding to the feeding point) of the dielectric substrate 2. As a result, the antenna element (patch antenna 1) is completed by inserting the feeding pin 5 into the through-hole 2a in the manufacturing stage and then soldering the head of the feeding pin 5 to the radiation conductor 3, thereby simplifying the manufacturing process. This makes it easier to reduce costs.
JP-A-6-152237 (2nd page, FIG. 5)

  In the conventional patch antenna 1 described above, at the design stage, a feeding point is set at a position where an optimum impedance matching is obtained (for example, a position corresponding to 50Ω from the center point of the radiation conductor 3). Since the through-hole 2a to be formed is formed at the time of molding the dielectric substrate 2, the head of the feed pin 5 inserted into the through-hole 2a is arranged at a desired feed point. However, when the patch antenna 1 is used as, for example, a GPS antenna for in-vehicle navigation, the patch antenna 1 as an antenna element is covered with a dust-proof radome and installed on a metal bracket. There is a possibility that the input impedance changes due to the influence of the retrofitting member, and the position of the feeding point at which the optimum impedance matching is obtained shifts. Of course, if only one type of radome or bracket is used, the position of the feeding point can be adjusted in consideration of the effect in advance, but in reality it can be applied to a wide variety of radomes and brackets. Therefore, there are cases where the product is commercialized in a state where the feeding point is greatly deviated from the optimum position. In this case, the antenna performance is deteriorated due to a decrease in gain. In addition, since patch antennas that do not achieve desired antenna performance when commercialized are defective, such feed point misalignment has also been a factor in reducing manufacturing yield.

  Note that the phenomenon that the feeding point deviates from the optimum position also occurs due to variations in the dielectric material of the dielectric substrate 2 (variations in dielectric constant). In addition, in order to avoid the displacement of the feeding point, if the dielectric substrate 2 having the optimum shape is prepared each time depending on the radome or bracket to be used, the mold of the dielectric substrate 2 cannot be made common, so that the manufacturing cost is reduced. Will be forced to soar.

  The present invention has been made in view of the actual situation of the prior art, and its purpose is to ensure the desired antenna performance by supplying power to the optimum feeding point even if the mounting environment and component materials vary. Is to provide an easy patch antenna.

  In order to achieve the above-described object, in the patch antenna of the present invention, a dielectric substrate, a radiation conductor provided on one surface of the dielectric substrate, a ground conductor provided on the other surface of the dielectric substrate, A feed pin penetrating through the dielectric substrate and having one end connected to the radiation conductor and the other end connected to a feed circuit, the dielectric substrate having a plurality of through holes corresponding to different feed points, The power feed pin is inserted into one through hole.

  In the patch antenna configured as described above, since a plurality of through holes are provided in advance in the dielectric substrate, a through hole into which the feed pin is inserted can be appropriately selected. In other words, in addition to providing a through hole at a position that matches the feeding point determined to be optimal at the design stage, variations in the mounting environment due to the diversity of retrofit members such as radomes and brackets, or parts such as dielectric substrates In consideration of material variations, etc., by providing another through-hole at a position slightly shifted from the through-hole, a through-hole that substantially matches the optimum feeding point when commercialized is selected. A power supply pin can be inserted into the. Therefore, this patch antenna can easily feed power to the optimum feeding point even if there are variations in the mounting environment and component materials, and there is no fear that the manufacturing cost will increase.

  The patch antenna of the present invention has a structure in which a plurality of through holes corresponding to different feeding points are provided in a dielectric substrate, and one of these through holes is appropriately selected to insert a feeding pin. Therefore, it is possible to always connect the power feed pin to the optimum power feed point even if there are variations in the mounting environment and component materials. Therefore, desired antenna performance can be easily secured without complicating the manufacturing process, the manufacturing yield can be improved, and a highly reliable patch antenna can be provided at low cost.

  1 is a plan view of a patch antenna according to an embodiment of the present invention, and FIG. 2 is a cross-sectional view showing a state in which the patch antenna is mounted on a circuit board. is there.

  The patch antenna 11 shown in these drawings includes a dielectric substrate 12 made of a dielectric material such as ceramic and having through holes 12a to 12c at three locations, and a square-shaped radiation conductor (provided on the upper surface of the dielectric substrate 12). Patch electrode) 13, ground conductor (back electrode) 14 provided on the bottom surface of dielectric substrate 12, and feed pin 15 that penetrates dielectric substrate 12 and is connected to the feed point of radiation conductor 13. The power feed pin 15 is inserted into any one of the through holes 12a to 12c (the through hole 12b in the figure).

  The through holes 12a to 12c of the dielectric substrate 12 are exposed to the radiating conductor 13 as open ends having substantially equal intervals at the upper ends, and the distance from the through holes 12a to 12c to the center point of the radiating conductor 13 is It is formed in a slightly different arrangement. That is, the through hole 12a is closest to the center point of the radiation conductor 13, the through hole 12b is next, and the through hole 12c is formed at the farthest position. Among these, the upper end of the through hole 12b is located at a feeding point (specifically, a point determined to correspond to 50Ω from the center point of the radiating conductor 13) at which the optimum impedance matching is determined at the design stage. ing.

  The radiation conductor 13 and the ground conductor 14 are made of a highly conductive metal such as a copper foil, and are formed in a predetermined shape by etching or the like. In the present embodiment, the radiation conductor 13 is formed in a square shape, but may be a circular shape or the like. The ground conductor 14 is formed on substantially the entire bottom surface of the dielectric substrate 12 except for the peripheral portions of the through holes 12a to 12c. The power feed pin 15 is a highly conductive metal pin, and its upper end (head) is soldered to the radiation conductor 13. Further, the lower end portion of the power supply pin 15 is insulated from the ground conductor 14 and protrudes below the dielectric substrate 12, and is soldered to the land portion 21 of the power supply circuit (not shown) on the back surface of the circuit substrate 20.

  The patch antenna 11 configured as described above is covered with a dust-proof radome and placed on a metal bracket when commercialized. Generally, the radome and the bracket have various shapes and sizes. For this reason, the input impedance of the patch antenna 11 may change due to the influence of a radome, a bracket, or the like to be used, and the position of the feeding point where optimum impedance matching is obtained may be shifted. In addition, variations in the dielectric material of the dielectric substrate 12 (variations in dielectric constant) may change the input impedance and shift the optimum feed point position. That is, the illustrated patch antenna 11 has the feed pin 15 inserted in the through hole 12b corresponding to the feed point determined to be the optimum position at the design stage. Due to variations in mounting environment due to variations in component materials such as the dielectric substrate 12, there is a possibility that the position of the optimum feeding point may be greatly shifted. In this case, the desired antenna performance can be obtained even if commercialized. Will be difficult.

  Therefore, in this embodiment, when the position of the optimum feeding point greatly deviates toward the center point side of the patch antenna 11 due to the variation in the mounting environment and component materials, the feeding pin 15 is changed to the through hole 12a instead of the through hole 12b. Accordingly, the feeding point can be set at a substantially optimal position. Further, when the position of the optimum feeding point is greatly shifted to the peripheral side (the side away from the center point) of the patch antenna 11 due to variations in the mounting environment and component materials, the feeding pin 15 is changed to the through hole 12c instead of the through hole 12b. Accordingly, the feeding point can be set at a substantially optimal position.

  When inserting the power feed pin 15 into the through hole 12a or the through hole 12c, the land portion 21 shown in FIG. 2 is formed at the lower end of the power feed pin 15 by appropriately changing the mounting position of the patch antenna 11 on the circuit board 20. Can be soldered to. However, a plurality of land portions corresponding respectively to the through holes 12a to 12c may be provided in the circuit board 20 in advance.

  As described above, the patch antenna 11 according to the present embodiment is provided with the plurality of through holes 12 a to 12 c in the dielectric substrate 12 in advance, so that a through hole into which the feed pin 15 is inserted can be appropriately selected. That is, not only the through hole 12b is provided at a position that matches the feeding point determined to be optimal in the design stage, but also variations in the mounting environment due to the diversity of retrofitting members such as radomes and brackets, or the dielectric substrate 12 and the like. In consideration of the variation of the parts materials, by providing another through hole 12a, 12c at a position slightly shifted from the through hole 12b, a through hole that substantially matches the optimum feeding point when commercialized is obtained. A power supply pin 15 can be inserted there. Therefore, the patch antenna 11 can always connect the power supply pin 15 to the optimal power supply point even if the mounting environment and the parts material vary, and the desired antenna performance can be obtained without complicating the manufacturing process. Easy to secure. Moreover, since the manufacturing yield is improved, cost reduction can be expected.

  In the above-described embodiment, the linearly polarized patch antenna is illustrated. However, it goes without saying that the present invention can be applied to a circularly polarized patch antenna. Further, the number of through holes into which the power supply pins can be selectively inserted may be two or four or more.

It is a top view of the patch antenna concerning the example of an embodiment of the present invention. It is sectional drawing which shows this patch antenna mounted on the circuit board. It is sectional drawing of the patch antenna which concerns on a prior art example.

Explanation of symbols

DESCRIPTION OF SYMBOLS 11 Patch antenna 12 Dielectric board 12a-12c Through-hole 13 Radiation conductor 14 Ground conductor 15 Feed pin 20 Circuit board 21 Land part

Claims (1)

A dielectric substrate, a radiation conductor provided on one surface of the dielectric substrate, a ground conductor provided on the other surface of the dielectric substrate, and one end penetrating the dielectric substrate connected to the radiation conductor; The other end of the dielectric substrate has a plurality of through holes corresponding to different power feeding points, and the power feeding pins are inserted into one of the through holes. A patch antenna characterized by.

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