JP2000216508A - High frequency electronic apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent generation of spurious radiation by eliminating voltage difference which is generated between ground conductors of the upper and the lower surfaces of a printed board constituting a high frequency circuit. SOLUTION: This high frequency electronic apparatus has a metal case 1 and a printed board 2 accommodated in the metal case 1. Ground conductors 2a, 2b are formed at least on the upper and the lower surfaces of a corner part of the printed board 2. Through holes 7 are formed in the vicinity the corner part, and the ground conductors 2a, 2b are connected with each other by using the through holes 7. As a result, the two ground conductors 2a, 2b have the same potential, and spurious radiation is not generated.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a high-frequency electronic device such as a television tuner or a transmitting / receiving unit of a portable telephone.

[0002]

2. Description of the Related Art A conventional high-frequency electronic device will be described with reference to FIGS. As shown in FIG. 5, a printed circuit board 32 is housed in the square metal case 31. The printed circuit board 32 is fixed to the metal case 31 by appropriate means (not shown). As shown in FIG. 6, a first ground conductor 32a is provided on the periphery of the upper surface of the printed circuit board 32.
Are formed, and the first ground conductor 32a is soldered to the inner surface of the side wall 31a of the metal case 31 at a plurality of appropriate positions 33.

Further, on the upper surface of the printed circuit board 31, a first high-frequency circuit 34 is formed in a region surrounded by a first ground conductor 32a. The high-frequency circuit 34 is composed of a plurality of function circuits, and most of the function circuits are connected to the first ground conductor 32 a near the solder connection position 33. In the region where the high-frequency circuit 34 is formed, the first functional circuits 34a and 34a formed near the corner of the printed circuit board 32 are connected to the first ground conductor 3 near the corner.
2a.

On the other hand, on the lower surface of the printed circuit board 32, similarly to the upper surface, a second ground conductor 32b (see FIG. 7) is formed on the periphery, and the second ground conductor 32b is formed in a region surrounded by the second ground conductor 32b. Two high-frequency circuits (not shown) are configured. Further, a second functional circuit (not shown) of the second high-frequency circuit, which is configured near the corner of the printed circuit board 32, is connected to the second ground conductor 32b near the corner. Then, the first ground conductor 32a and the second ground conductor 32b are connected to each other by a conduction hole 35 provided near the solder connection position 33 so that they have the same ground potential.

With the above configuration, in the corner portion of the printed board 32, the first functional circuit 34a and the second functional circuit are configured to face the upper and lower surfaces of the printed board 32. Then, the high-frequency electronic device is configured by closing the opening of the metal case 31 with a metal cover (not shown).

[0006]

In the above-mentioned conventional high-frequency electronic equipment, when the first functional circuit 34a on the upper surface of the printed circuit board 32 and the second functional circuit on the lower surface operate, an operating current flows through each functional circuit. Accordingly, a high-frequency ground current flows through the first ground conductor 32a and the second ground conductor 32b at the corners. Then, this ground current flows toward the solder connection position 33. Then, the first ground conductor 32
Impedance of a (resistance component and inductance component)
The first functional circuit 34a and the first ground conductor 32a
A voltage is generated between the connection point of
The voltage at the connection point between the first functional circuit 34a and the first ground conductor 32a varies according to the operation of the first functional circuit.

Similarly, a voltage is generated between the connection point between the second functional circuit and the second ground conductor 32b and the solder connection position 33 by the impedance (resistance component or inductance component) of the second ground conductor 32b. The voltage at the connection point between the second functional circuit and the second ground conductor 32b fluctuates according to the operation of the second functional circuit. Then, a voltage difference occurs between the two connection points, thereby generating unnecessary radiation.

Accordingly, it is an object of the high-frequency electronic device of the present invention to eliminate a voltage difference generated between ground conductors on both upper and lower surfaces of a printed circuit board constituting a high-frequency circuit, thereby preventing generation of unnecessary radiation.

[0009]

As a means for solving the above-mentioned problems, a metal case and a printed board housed in the metal case are provided, and ground conductors are formed on at least upper and lower surfaces of a corner portion of the printed board. Then, a through hole was provided near the corner portion, and the ground conductors were connected to each other by the through hole.

In the high frequency electronic device of the present invention, a plurality of the through holes are provided.

Further, in the high-frequency electronic device of the present invention, the through holes are provided side by side along the inner wall of the metal case.

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A high-frequency electronic device according to the present invention will be described with reference to FIGS. FIG. 1 is a perspective view of the high-frequency electronic device of the present invention, FIG. 2 is a top view of the high-frequency electronic device of the present invention,
FIG. 3 is a rear view of the high-frequency electronic device of the present invention, and FIG. 4 is a sectional view of a main part of the high-frequency electronic device of the present invention.

In FIG. 1, a rectangular metal case 1 has upper and lower openings, and a printed circuit board 2 is housed in the metal case 1. The printed board 2 is held on the metal case 1 by an appropriate means (not shown). As shown in FIGS. 1 and 2, a first ground conductor 2 a is formed on the periphery of the upper surface of the printed circuit board 2, and the first ground conductor 2 a
Is connected to the inner surface of the side wall 1a of the metal case 1 by solder at an appropriate connection position 3.

Further, on the upper surface of the printed circuit board 2, a first high-frequency circuit 4 is formed in a region surrounded by the first ground conductor 2a. The high-frequency circuit 4 is composed of a plurality of function circuits, and most of the function circuits are connected to the first ground conductor 2a near the connection position 3. Further, in a region where the high-frequency circuit 4 is configured, in the vicinity of a corner portion of the printed circuit board 2, for example, a first functional circuit 4a such as a high-frequency amplifier circuit and a second functional circuit 4b are configured. The functional circuit 4a and the second functional circuit 4b are connected to the first ground conductor 2a in the vicinity of each corner.

On the other hand, on the lower surface of the printed circuit board 32, FIG.
As shown in the figure, the second ground conductor 2
b is formed, and a second high-frequency circuit 5 is formed in a region surrounded by the second ground conductor 2b. In the second high-frequency circuit 5, a third functional circuit 5a and a fourth functional circuit 5b such as a high-frequency amplifier circuit are also provided near the corner of the printed circuit board 2. These functional circuits 5a and 5b are also connected to the second ground conductor 2b near each corner.

In the vicinity of the connection position 3, there is provided a first through hole 6 for conducting both sides of the printed circuit board 2, and the first ground conductor 2a and the second ground conductor 2b are connected to the first ground conductor 2b. The first ground conductor 2a and the second ground conductor 2b are connected to each other by a through hole 6, so that they have the same ground potential.

Furthermore, a plurality of second through holes 7 are formed near the corners of the printed circuit board 2 in the side wall 1 of the metal case 1.
As shown in FIG. 4, the first ground conductor 2a and the second ground conductor 2b in the vicinity of the corner are formed along
Are connected by a second through hole 7. As a result, the first ground conductor 2a and the second ground conductor 2b have the same potential along their length.

With the above structure, in the vicinity of the corner of the printed circuit board 2, the first functional circuit 4a and the third functional circuit 5a are opposed to each other on the upper and lower surfaces of the printed circuit board 2. Second functional circuit 4b and fourth functional circuit 5
b are opposed to each other on the upper and lower surfaces of the printed circuit board 2. Then, the high-frequency electronic device is configured by closing the opening of the metal case 1 with a metal cover (not shown).

In the above high-frequency electronic device, when the first to fourth functional circuits 4a, 4b, 5a, 5b operate,
An operating current flows through each functional circuit, and accordingly, a high-frequency ground current flows through the first ground conductor 2a and the second ground conductor 2b near the corner. This ground current flows toward the solder connection position 3.

At this time, the vicinity of the connection point between the first functional circuit 4a and the first ground conductor 2a and the vicinity of the connection point between the third functional circuit 5a and the second ground conductor 2b are two ground conductors. 2
Since a and 2b are connected by the second through-hole 7, no voltage difference occurs between the two connection points. Similarly, the second functional circuit 4b and the second ground conductor 2a
And the vicinity of the connection point between the fourth functional circuit 5b and the second grounding conductor 2b, the two grounding conductors 2a and 2b are connected by the second through-hole 7. No voltage difference occurs between the connection points. Therefore, unnecessary radiation does not occur near these connection points.

[0021]

As described above, the high-frequency electronic device of the present invention has a metal case and a printed circuit board housed in the metal case, and has ground conductors formed at least on both upper and lower corners of the printed circuit board. Since the through-holes are provided near the corners and the grounding conductors are connected to each other by the through-holes, the two grounding conductors have the same potential and do not generate unnecessary radiation.

Further, since the high-frequency electronic device of the present invention is provided with a plurality of through holes, the two ground conductors can have the same potential.

Further, in the high-frequency electronic device of the present invention, the through holes are arranged along the inner wall of the metal case.
The two ground conductors are uniformly at the same potential in the longitudinal direction, and the prevention of unnecessary radiation is more effective.

[Brief description of the drawings]

FIG. 1 is a perspective view of a high-frequency electronic device according to the present invention.

FIG. 2 is a top view of the high-frequency electronic device of the present invention.

FIG. 3 is a rear view of the high-frequency electronic device of the present invention.

FIG. 4 is a sectional view of a main part of the high-frequency electronic device of the invention.

FIG. 5 is a perspective view of a conventional high-frequency electronic device.

FIG. 6 is a top view of a conventional high-frequency electronic device.

FIG. 7 is a sectional view of a main part of a conventional high-frequency electronic device.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Metal case 1a Side wall 2 Printed circuit board 2a First ground conductor 2b Second ground conductor 3 Solder connection position 4 First high frequency circuit section 4a First functional circuit 5 Second high frequency circuit section 5a Second functional circuit 6 First conduction hole 7 Second conduction hole

Continued on the front page F term (reference) 5E317 AA24 BB01 BB11 CC15 CC31 GG11 5E338 AA02 BB02 BB13 BB25 BB75 CC01 CC06 CD01 EE13

Claims (3)

[Claims] 1. A printed circuit board comprising: a metal case; and a printed circuit board housed in the metal case. Ground conductors are formed on at least upper and lower surfaces of the corner portion of the printed circuit board. Wherein the ground conductors are connected to each other by the through holes. 2. The high-frequency electronic device according to claim 1, wherein a plurality of said through holes are provided. 3. The high-frequency electronic device according to claim 1, wherein the through holes are provided along the inner wall of the metal case.