JP2885707B2 - Plate antenna - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a plate antenna in which a wide surface of a plate conductor forming an antenna element is opposed to a circuit board at a predetermined interval.

[0002]

2. Description of the Related Art A plate-type antenna of this type has been awarded as an antenna for a small radio device such as a portable radio device due to its low-profile antenna shape. Hereinafter, a conventional plate antenna will be described with reference to the perspective view of FIG. FIG. 3 shows a state before the antenna element 309 which is a radiation element of the plate antenna is assembled on the circuit board 310.

A circuit board 310 has a wiring pattern such as a power supply point 301 and a ground plane 302 formed on one surface of a dielectric substrate. The wiring pattern includes a wiring pattern for a radio device circuit. A plurality of radio circuit components (not shown) are usually connected to each other by the wiring pattern. On the back surface (not shown) of the circuit board 310, a ground conductor layer is usually formed over the entire surface.

The antenna element 309, which is a substantially rectangular quadrangular plate-shaped conductor, has a wide surface directed toward the opposing surface of the circuit board 310, that is, toward a surface on which a wiring pattern such as a feeding point 301 or a ground surface 302 is formed. Are arranged at predetermined intervals. A feed terminal 306 is provided near the vertex of the side on the wide surface of the antenna element 309. The power supply terminal 306 is formed by bending the wide surface of the antenna element 309 at right angles toward the circuit board 310 around the periphery, and connecting the front end of the bent to the circuit board 31.
It is further bent at a right angle so as to substantially match the pattern of the ground plane 302 of the zero. A power supply terminal 305 is provided at a predetermined position along the periphery of the antenna element 309 from the power supply terminal 306. The power supply terminal 305 supplies an electric signal to the antenna element 309 together with the power supply terminal 306 for supplying an electric signal on the ground potential side. Power supply terminal 305
Is formed by bending the wide surface of the antenna element 309 on the same side as the power supply terminal 306 toward the circuit board 310 by sheet metal processing or the like.
The leading end of this bend is connected to the feeding point 301 of the circuit board 310.
Are further bent so as to substantially match the pattern of FIG.

In FIG. 3, the integrally formed product of the antenna element 309 and the power supply terminals 305 and 306 is separated from the circuit board 310 at intervals of a broken line. By bringing these two components closer together, the feed point 301 and the ground plane 302
Then, the surfaces of the power supply terminals 305 and 306 facing the power supply point 301 and the ground plane 302 are soldered. By this soldering, the power supply terminal 305 and the power supply point 301, and the power supply terminal 306 and the ground plane 302 are mechanically fixed and electrically connected, respectively, and the plate antenna is completed.

Here, in this plate antenna, it is necessary to prevent a change in the characteristics due to a change in the position of the plate antenna element 309 relative to the circuit board 310. Therefore, in this plate antenna, the antenna element 309 and the circuit board 3
An insulator spacer 303 is inserted between the antenna element 301 and the antenna element 301 to prevent the position of the antenna element 301 from fluctuating and support the weight of the antenna element 301. The spacer 303 is a circuit board 3 with a double-sided adhesive tape.
10 and the antenna element 309. Although a plurality of radio circuit components are mounted between the antenna element 309 and the circuit board 310, the position fluctuation of the element 309 is suppressed by the spacer 303, and the antenna element 309 and the radio circuit circuit are mounted. Contact with parts is also prevented.

[0007]

In recent years, small wireless devices such as portable telephones have been increasingly required to be lighter, thinner and smaller, and plate antennas have been required to be further reduced in size. I have.

Further, in the plate antenna according to the above-mentioned technology, the spacer for fixing the position of the antenna element is adhered to the antenna element and the circuit board with a double-sided adhesive tape, but the spacer itself may be arranged in a stable position. However, the position of the antenna element is also unstable, so that it is difficult to keep the characteristics of the plate antenna optimal.

Accordingly, it is an object of the present invention to further reduce the size of the plate antenna and improve the stability of the characteristics, and to improve the productivity of the plate antenna by eliminating the need for inserting the spacer.

[0010]

A plate antenna according to the present invention has a circuit board in which a wiring pattern is formed on one surface of a dielectric substrate, and a wide surface of the plate-like conductor is provided at a predetermined interval on one surface of the dielectric substrate. And a feeding terminal for fixedly coupling and electrically connecting the plate-shaped conductor and a feeding point provided on the wiring pattern, wherein the antenna element constitutes an open end of the antenna element. A fixed leg for fixedly and electrically coupling a peripheral portion of the plate-shaped conductor and a land provided on the wiring pattern is provided, and the circuit board is provided on the other surface of the dielectric substrate corresponding to the land. A ground conductor layer is arranged, and the fixed leg is
Bend the wide surface of the conductor toward the circuit board around
And the tip of this bend is
Further fold to almost match the land pattern
Between the land and the ground conductor layer.
Make up .

[0011]

In the plate antenna, the wide surface of the plate conductor is substantially a quadrilateral, and at least one of the power supply terminals and at least one of the fixed legs are located near a vertex of the quadrilateral. The configuration in which they are arranged can be adopted.

[0013] The plate antenna according to the present invention comprises a peripheral portion of the plate conductor substantially opposite to a side of the plate conductor provided with the power supply terminal, that is, an open end of the antenna element; A land provided at a position on the wiring pattern substantially opposite to the open end is fixedly and electrically coupled with a fixed leg, so that the antenna element can be connected to the circuit board without using a spacer. The positional relationship can be stabilized, and the characteristics of the plate antenna can be kept optimal.

Further, in the plate antenna according to the present invention, since the circuit board has a ground conductor layer disposed on the other surface of the dielectric substrate corresponding to the land, the tip of the fixed leg is connected to the ground potential. And a capacitor is formed between them. Since this capacitor operates as a loading capacitor, the plate antenna according to the present invention can reduce the plate area (for example, length) of the antenna element at the same frequency as that of the prior art plate antenna, and achieve miniaturization. it can.

[0015]

Next, the present invention will be described with reference to the drawings. 1A and 1B are views showing one embodiment of a plate antenna according to the present invention, wherein FIG. 1A is a perspective view before assembly, and FIG. 1B is an equivalent circuit diagram. FIG. 2 is a sectional view showing the part A in FIG. 1 after assembly .

Referring to FIGS. 1 and 2, the circuit board 110 of the plate antenna shown in FIG. 1 has a wiring pattern such as a feeding point 101 and a ground plane 102 formed on one surface of a dielectric substrate 201. The wiring pattern includes a wiring pattern for a radio device circuit. A plurality of radio circuit components (not shown) are usually connected to each other by the wiring pattern. On the back surface (not shown) of the circuit board 110, a conductor layer 202 for grounding the wiring pattern is formed.

The antenna element 109, which is a substantially rectangular quadrangular plate-like conductor, has its wide surface directed toward the opposing surface of the circuit board 110, that is, toward the surface on which a wiring pattern such as the feeding point 101 and the ground surface 102 is formed. Are arranged facing each other at a predetermined interval. A feeding terminal 106 is provided near the vertex of the side on the wide surface of the antenna element 109. Power supply terminal 10
6 is a circuit board 11 around the wide surface of the antenna element 109.
It is bent at a right angle toward zero, and the leading end of the bent is further bent at a right angle so as to substantially match the pattern of the ground plane 102 of the circuit board 110. Power supply terminal 1
A feeding terminal 105 is provided at a predetermined position from 06 to a position around the antenna element 109. The power supply terminal 105
The electric signal is supplied to the antenna element 109 together with the power supply terminal 106 for supplying the electric signal on the ground potential side. The power supply terminal 105 connects the wide surface of the antenna element 109 to the power supply terminal 10.
6, the circuit board 110 is bent toward the circuit board 110 by sheet metal processing or the like, and the leading end of this bending is further bent so as to substantially match the pattern of the feeding point 101 of the circuit board 110.

In the antenna element 109 which is a rectangular plate-shaped conductor, fixed legs 107 and 108 are separately provided on opposite sides of the side where the feed terminals 105 and 106 are arranged, that is, on the open end of the antenna element 109. Are arranged in the vicinity of the vertex of. These fixed legs 107 and 10
Similarly to the power supply terminals 105 and 106, the wide surface of the antenna element 109 is bent at a right angle toward the circuit board 110 around the periphery, and the leading end of this bending matches the pattern of the lands 103 and 104 of the circuit board 110, respectively. And bent at a right angle as described above.
08a. The lands 103 and 104 are formed in advance as wiring patterns on the circuit board 110 so as to correspond to the positions and shapes of the fixing portions 107a and 108a.

Antenna element 109, feeding terminal 105, 1
06 and the fixed legs 107 and 108 are integrally formed as shown in FIG.
Is separated from the circuit board 110 at intervals of a broken line. By bringing these two parts close together,
And a surface of the ground plane 102 facing the power supply point 301 and the ground plane 302 of the power supply terminals 105 and 106;
Fixed portions 107a and 108a and lands 103 and 1
03 are soldered. By this soldering,
The power supply terminal 105 and the power supply point 101, the power supply terminal 106 and the ground plane 102, the fixed portion 107a and the land 103, and the fixed portion 108a and the land 104 are mechanically fixed and electrically connected, respectively. The plate antenna is completed. This plate-shaped antenna has an antenna element 10
9, power supply terminals 105 and 106, fixed legs 1
Since the antenna element 109 is fixed to the circuit board 110 by four fixing mechanisms 07 and 108, the positional relationship between the antenna element 109 and the circuit board 110 can be stabilized without using a spacer, and There is an effect that characteristics can be kept optimal.

When the fixing portion 108a and the land 104 of the circuit board 110 are soldered (see FIG. 2), the fixing portion 10
8a and the conductor layer 202 at the ground potential are connected to the capacitor C2.
Is configured. As is well known, the capacity of the capacitor C2 is
Relative permittivity and thickness of the dielectric substrate 201, the fixing portion 108
It is determined by the area of a. Similarly, the fixing portion 107a
When the and the land 103 are soldered, the fixing portion 107a
And the conductor layer 202 constitute a capacitor C1. Therefore, the plate antenna according to the present embodiment has the equivalent circuit of FIG. The plate antenna according to FIG. 1 (b) has capacitors C1 and C2 connected to antenna element 1
Since the antenna is arranged at the open end of the antenna 09 and operates as a loading capacitor, at the same frequency, the fixed leg from the plate area of the antenna element 109 or the side of the feeding terminals 105 and 106 from the antenna element 309 of the plate antenna of FIG. 1
The length to the side of 07,108 can be reduced,
Miniaturization can be achieved.

[0021]

As described above, the present invention is applicable to the peripheral portion of the plate-like conductor which is substantially opposed to the side of the feeding terminal of the antenna element having the plate-like conductor as the radiation element, that is, to the open end. A fixing leg is fixedly and electrically coupled to a land provided on a wiring pattern of a circuit board facing the fixing leg, and the circuit board is grounded to the other surface of the dielectric substrate corresponding to the land. Since the conductor layer is disposed, the positional relationship between the antenna element and the circuit board can be stabilized without using a spacer that lowers the production efficiency, and the characteristics of the plate antenna can be improved. There is an effect that can be kept optimal.

Further, in this plate antenna, since a loading capacitor is provided between the fixed leg and the ground conductor layer of the circuit board, the area of the antenna element can be reduced, and therefore, the size of the antenna can be reduced. This has the effect of being able to be converted.

[Brief description of the drawings]

FIG. 1 is a diagram showing an embodiment of a plate antenna according to the present invention, wherein (a) is a perspective view before assembly and (b) is an equivalent circuit diagram.

FIG. 2 is a sectional view showing a part A after assembly in FIG. 1;

FIG. 3 is a perspective view of a conventional plate antenna before assembly.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 101 Feeding point 102 Ground plane 103, 104 Land 105, 106 Feeding terminal 107, 108 Fixed leg 107a, 108a Fixed part 109 Antenna element 110 Circuit board 201 Dielectric substrate 202 Conductive layer

Continuation of front page (56) References JP-A-7-297626 (JP, A) JP-A-64-7702 (JP, A) JP-A-7-131234 (JP, A) JP-A-2-114795 (JP) JP-A-7-221536 (JP, A) JP-A-7-288422 (JP, A) JP-A-4-172001 (JP, A) (58) Fields investigated (Int. Cl. ⁶ , DB Name) H01Q 9/00-9/46 H01Q 13/00-13/28

Claims (2)

(57) [Claims] A circuit board having a wiring pattern formed on one surface of a dielectric substrate; an antenna element having a wide surface of a plate-shaped conductor facing the one surface of the dielectric substrate at a predetermined interval; And a power supply terminal for fixedly coupling and electrically connecting a power supply point provided on the wiring pattern to a peripheral portion of the plate-shaped conductor forming an open end of the antenna element and on the wiring pattern. the land provided comprises a fixed and a fixed leg of electrically coupling said circuit board, it is arranged ground conductor layer on the other surface of the dielectric substrate corresponding to the land, the fixed leg However, the wide surface of the plate-shaped conductor is
And bent toward the circuit board.
To the land pattern on the wiring pattern.
Bend further so that the land and the ground conductor
Characterized by forming a capacitor between the body layer
Plate antenna. 2. The wide surface of the plate-like conductor is substantially a quadrilateral, and at least one of the power supply terminals and at least one of the fixing legs are arranged near a vertex of the quadrilateral. The plate antenna according to claim 1, wherein: