JP3548294B2 - Diversity antenna - Google Patents

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a diversity antenna, and more particularly to a small-sized planar structure diversity antenna that is installed in a narrow room or the like where a multiple polarization environment with little polarization preservation is obtained.
[0002]
[Prior art]
2. Description of the Related Art Conventionally, as an antenna suitable for mobile communication such as a simplified mobile phone, for example, as disclosed in JP-A-5-102897, the antenna is installed in a narrow room where a multi-polarization environment with little polarization preservation is provided. A compact planar diversity antenna with a capacitance-loaded monopole antenna with matching pins for vertical polarization and a notch antenna for horizontal polarization arranged around the axis symmetrically at a 120-degree pitch about the axis with a 120-degree pitch. There was a diversity antenna with a structure.
[0003]
[Problems to be solved by the invention]
However, in the conventional combination of a capacitance-loaded monopole antenna with a matching pin and a notch antenna, in order to widen the band of the notch antenna, there is a design limitation on the capacitance-loading monopole antenna with a matching pin. However, there is a problem that it is difficult to widen the band.
[0004]
[Means for Solving the Problems]
In order to solve such a problem and realize a diversity antenna capable of suitably widening the band of the notch antenna in a small-sized planar structure diversity antenna in which the notch antenna for horizontal polarization is arranged, in the present invention, A plurality of notches which are cut in the radial direction so that a part of the conductor layer laminated on one surface of the circular insulating substrate is opened at a predetermined width on the outer peripheral edge thereof and are provided at substantially equal pitch intervals in the circumferential direction. And a notch antenna for horizontal polarization composed of a power supply line formed on the other surface of the circular insulating substrate to excite each of the notch portions, and an erect antenna standing substantially at the center of the circular insulating substrate. The wire-shaped conductor is branched approximately symmetrically with respect to the axis thereof, extends in parallel with the circular insulating substrate, and then hangs down on the periphery of the circular insulating substrate to be connected to the conductor layer. A wave loop antenna, or a part of a conductor layer laminated on one surface of a circular insulating substrate is cut in a radial direction so as to open with a predetermined width on an outer peripheral edge thereof and is formed in a circumferential direction. A plurality of notch portions provided at substantially equal pitch intervals, and a notch antenna for horizontal polarization configured by a feed path formed on the other surface of the circular insulating substrate to excite each of the notch portions, A circular ground plate disposed parallel to the one surface side of the circular insulating substrate at an interval and laminated with a conductor layer for loop antenna, and the circular insulating substrate is disposed substantially at the center of the circular ground plate. The vertical wire-like conductor penetrates through the wire-like conductor, branches approximately symmetrically with respect to the axis thereof, extends in parallel with the circular insulating substrate, and then hangs down to penetrate the periphery of the circular insulating substrate. The root of the main plate It consisted of a loop antenna for vertically polarized waves formed by connecting the conductor layer for the antenna.
[0005]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, embodiments of the present invention will be described in detail based on specific examples shown in the accompanying drawings.
[0006]
FIG. 1 is a perspective view showing a first example of a small size diversity antenna to which the present invention is applied. The diversity antenna 1 includes a notch antenna 2 for horizontal polarization and a loop antenna 3 for vertical polarization.
[0007]
As shown in the top view of FIG. 2 and the sectional side view of FIG. 3, a circular insulating substrate (circular dielectric substrate) coaxially fixed on an insulating thin plate-like donut-shaped support such as foamed styrene. On one surface (lower surface in the figure) of 4, a conductor layer 5, which may be, for example, a copper foil, is laminated so as to cover the entire lower surface, and a portion thereof is formed on the outer peripheral edge with a predetermined width in the circumferential direction. The fan-shaped notch 6 is cut in the radial direction so as to open. The notches 6 are provided at three places at substantially equal pitch intervals (120-degree pitch in the figure) in the circumferential direction.
[0008]
At the center of the circular insulating substrate 4, a notch antenna power supply connector 7 is fixed to the lower surface of the circular insulating substrate 4, and the coaxial pin 7 a of the connector 7 is circular with the conductor layer 5 insulated. It protrudes toward the other surface (the upper surface in the figure) of the insulating substrate 4. The base ends of three feeding paths 8 formed of narrow conductors formed on the upper surface of the circular insulating substrate 4 are collectively and electrically connected to the coaxial pin 7a. As shown in FIGS. 1 and 2, the three power supply paths 8 extend point-symmetrically from the coaxial pin 7 a toward the outer periphery of the circular insulating substrate 4, and bypass the side of the notch 6. It is bent so as to cross the opening of the notch portion 6.
[0009]
In the notch antenna 2 composed of the notch portion 6 and the feed line 8 formed in this way, when the feed line 8 is fed, the in-phase excitation is applied, so that the horizontal polarization is uniform. Directivity can be obtained.
[0010]
In the vicinity of the center of the circular insulating substrate 4, a loop antenna power supply connector 9 is fixed to the lower surface of the circular insulating substrate 4 in parallel with the notch antenna power supply connector 7. A copper wire 10 as a wire conductor coaxially connected to the loop antenna power supply connector 9 is insulated from the conductor layer 5 and protrudes from the upper surface of the circular insulating substrate 4 by a predetermined length. From the upper end thereof, branching in three directions (120 ° pitch in the circumferential direction) point-symmetrically with respect to the axis of the standing portion, and in parallel with the upper surface of the circular insulating substrate 4 and at the peripheral edge thereof. Partially bent and extended toward the circular insulating substrate 4 at a position corresponding to the vicinity of the peripheral edge portion, and is bent down and connected to the conductor layer 5. In the present loop antenna 3, each of the middle portions of the copper wire 10 branched in three directions is branched into two, and a total of six hanging portions 10a are provided. Are provided for adjusting the input impedance.
[0011]
As described above, the present loop antenna 3 is composed of three vertical loop antenna elements each having a height of 0.1λ and a length of 0.3λ. In the illustrated example, the single-point power is supplied by the loop antenna power supply connector 9 provided near the center, but three-point in-phase power may be supplied on the peripheral edge side. In any case, since the three loops are excited in phase, the radiation from the horizontal portion of the antenna (the portion parallel to the circular insulating substrate 4) is canceled by the video current flowing through the conductor layer 5, and only the vertical portion is radiated. To contribute.
[0012]
In the illustrated example, the power supply position by the notch antenna power supply connector 7 is provided at the center of the circular insulating substrate 4, and the power supply position by the loop antenna power supply connector 9 is provided slightly deviated from the center. The horizontal portion of the loop antenna 3 is absorbed by bending as shown in the figure or by shifting the bending position in the radial direction. Conversely, when the feeding position of the loop antenna 3 is provided at the center of the circular insulating substrate 4 and the feeding position of the notch antenna 2 is slightly shifted from the center, the shift is adjusted in the feeding path 8 of the notch antenna 2. Absorb by doing.
[0013]
4 to 6 show a second example of a diversity antenna to which the present invention is applied. The same parts as those in the above embodiment are denoted by the same reference numerals, and detailed description thereof will be omitted.
[0014]
In the diversity antenna 11, a circular ground plate 12 is arranged at a predetermined interval in parallel with a lower surface side of the circular insulating substrate 4 on which the notch antenna 2 is formed as in the illustrated example. In the illustrated example, the circular insulating substrate 4 and the circular ground plate 12 are disposed so as to sandwich an insulating thin plate-like donut-shaped support such as styrene foam.
[0015]
The notch antenna power supply connector 7 is fixed to the lower surface of the circular insulating substrate 4 in the same manner as in the illustrated example, but the loop antenna power supply connector 9 is fixed to the lower surface of the circular ground plate 12. A conductor layer 13 for a loop antenna, which may be, for example, a copper foil, is laminated on the lower surface of the circular ground plate 12 so as to cover the entire surface.
[0016]
The copper wire 14 as a wire conductor coaxially connected to the loop antenna power supply connector 9 is insulated from the loop antenna conductor layer 13 and the conductor layer 5 The circular insulating substrate 4 is also insulated, and stands upright so as to protrude from the upper surface side of the circular insulating substrate 4 by a predetermined length, and is point-symmetric with respect to the axis of the standing portion from the upper end. In the three directions (a pitch of 120 degrees in the circumferential direction) and partially bent toward the peripheral portion in parallel with the upper surface of the circular insulating substrate 4 so as to extend to a position corresponding to the vicinity of the peripheral portion. Is bent at a right angle toward the circular insulating substrate 4 side, and the circular insulating substrate 4 is insulated from the conductor layer 5 so as to penetrate and be connected to the loop antenna conductor layer 13. . In the diversity antenna 11 of the second example, a total of three hanging parts 14a are provided.
[0017]
In the present diversity antenna 11, by providing the circular ground plate 12 as described above, it becomes difficult to be affected by the vicinity of the installation location. In addition, the circular ground plane 12 affects the input impedance of the notch antenna 2 and the loop antenna 3, and thus can be used as a matching device.
[0018]
In each of the illustrated examples, three notch antennas 2 and three loop antennas 3 are provided at point-symmetric positions at a pitch of 120 degrees in the circumferential direction. However, the number of notch antennas and the loop antennas 3 is not limited to three. Any number may be used as long as it can obtain. Further, the conductor layer 5 forming the notch antenna 2 does not have to be formed on the lower surface of the circular insulating substrate 4, but may be formed on the upper surface and the power supply path 8 may be formed on the lower surface.
[0019]
【The invention's effect】
As described above, according to the present invention, the degree of freedom in designing the loop antenna is large, and therefore, the band of the notch antenna can be widened. In addition, since the notch antenna and the loop antenna are independently supplied with power, there is an advantage that isolation is large.
[Brief description of the drawings]
FIG. 1 is a perspective view showing a first example of a diversity antenna to which the present invention is applied.
FIG. 2 is a top view of the diversity antenna of FIG.
FIG. 3 is a side sectional view taken along the line II-II in FIG. 2;
FIG. 4 is a perspective view showing a second example of the diversity antenna to which the present invention is applied.
5 is a top view of the diversity antenna of FIG.
FIG. 6 is a side sectional view taken along the line VI-VI in FIG. 5;
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Diversity antenna 2 Notch antenna 3 Loop antenna 4 Circular insulating substrate 5 Conductor layer 6 Notch part 7 Notch antenna feeding connector 7a Coaxial pin 8 Feeding path 9 Loop antenna feeding connector 10 Copper wire 10a Hanging part 11 Diversity antenna 12 Circular ground plate 13 Conductor layer for loop antenna 14 Copper wire

Claims (2)

A plurality of notches which are cut in the radial direction so that a part of the conductor layer laminated on one surface of the circular insulating substrate is opened at a predetermined width on the outer peripheral edge thereof and are provided at substantially equal pitch intervals in the circumferential direction. Department and
A notch antenna for horizontal polarization constituted by a feed line formed on the other surface of the circular insulating substrate so as to excite the respective notches, and a wire-like antenna standing substantially at the center of the circular insulating substrate A vertically polarized loop formed by branching a conductor substantially point-symmetrically with respect to its axis and extending parallel to the circular insulating substrate, and then hanging down to a peripheral portion of the circular insulating substrate and connecting to the conductor layer. A diversity antenna comprising an antenna. A plurality of notches which are cut in the radial direction so that a part of the conductor layer laminated on one surface of the circular insulating substrate is opened at a predetermined width on the outer peripheral edge thereof and are provided at substantially equal pitch intervals in the circumferential direction. And a notch antenna for horizontal polarization constituted by a feed line formed on the other surface of the circular insulating substrate to excite each notch portion,
A circular ground plane is disposed parallel to the one side of the circular insulating board at an interval and a conductor layer for a loop antenna is laminated, and the circular insulating board is disposed substantially at the center of the circular ground plane. The standing wire-shaped conductor penetrates and branches approximately symmetrically with respect to the axis thereof, extends parallel to the circular insulating substrate, and then hangs down to penetrate the peripheral edge of the circular insulating substrate. A vertical polarization loop antenna connected to the loop antenna conductor layer.

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