Wave transmission lines and networks – Coupling networks – Balanced to unbalanced circuits
Reexamination Certificate
2001-04-18
2003-06-10
Lee, Benny (Department: 2817)
Wave transmission lines and networks
Coupling networks
Balanced to unbalanced circuits
C333S248000
Reexamination Certificate
active
06577206
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a converter for satellite broadcast or communication reception to receive a circularly polarized wave comprising a vertically polarized wave and a horizontally polarized wave.
2. Description of the Prior Art
A conventional converter for satellite broadcast reception will be described below with reference to
FIGS. 13
to
16
, of which
FIG. 13
is a perspective view of the conventional converter for satellite broadcast reception,
FIG. 14
is a sectional view taken on line
14
—
14
in
FIG. 13
,
FIG. 15
is an enlarged view of a principal portion, explaining a mounted state of a probe, and
FIG. 16
is an enlarged view of a principal portion, showing a mounted state of a circuit board.
As best seen in
FIGS. 13-14
, a housing
31
and a waveguide
32
are formed integrally using a metallic material such as die-cast aluminum or zinc. The housing
31
, which is formed in a generally rectangular box shape, comprises a bottom wall
31
a
, side walls
31
b
formed upright so as to enclose the bottom wall
31
a
while allowing an upper side to be open, a receptacle portion
31
c
enclosed with the side walls
31
b
, a vertical through hole
31
d
(see
FIG. 15
) formed in a position close to one end portion of the bottom wall
31
a
, and stepped portions
31
e
formed by cutting out peripheral edges of upper ends of the side walls
31
b
. The waveguide
32
is formed in a cylindrical shape relatively small in diameter and is projected from the bottom wall
31
a
at the position of the through hole
31
d
. The waveguide
32
comprises a generally cylindrical portion
32
b
having an opening
32
a
for introducing a polarized wave, a hollow portion
32
c
formed centrally in the longitudinal direction of the cylindrical portion, and a holding portion
32
d
formed as a semi-cylindrical recess within the cylindrical portion
32
b
, the holding portion
32
d
extending toward the opening
32
a
from a peripheral edge position of the through hole
31
d
formed in the housing
31
, as shown in FIG.
15
.
As best seen in
FIG. 15
, a probe
33
for catching a horizontally polarized wave is made up of a cylindrical insulating portion
33
a
formed of, for example, a fluorine resin, polyethylene, or Teflon, and a linear central conductor
33
b
piercing through the center of the insulating portion
33
a
and formed of a metal such as brass or nickel. The central conductor
33
b
has one end portion
33
c
which is bent approximately at right angles and an opposite end portion
33
d
which is rectilinear.
As shown in
FIG. 16
, a single rectangular circuit board
34
formed by an insulating board comprises a thin flat plate portion
34
a
, three vertical through holes
34
b
formed near a side edge of the flat plate portion
34
a
, bridge portions
34
d
and
34
e
which are formed in T shape, and a small hole
34
c
formed near the through hole
34
b
. A copper-clad earth conductor
35
is formed on a lower surface of the circuit board
34
except the lower surface portion where the bridge portion
34
e
is formed. A lower surface of the bridge portion
34
d
functions as a short-circuit rod for the probe
33
.
A probe
36
for catching a vertically polarized wave is formed as a conductive pattern on an upper surface of the flat plate portion, extending from an intersecting point of the bridge portions
34
d
and
34
e
toward the flat plate portion
34
a
, and is connected to a circuit pattern (not shown) formed on an upper surface of the flat plate portion
34
a
. The through hole
31
d
formed in the housing
31
and the through holes
34
b
formed in the flat plate portion
34
a
are opposed to each other and the opposite end portion
33
d
of the central conductor
33
b
of the probe
33
is inserted through the hole
34
c
formed in the flat plate portion
34
a
. In this state the circuit board
34
of the above configuration placed on the bottom wall
31
a
of the housing
31
and is fixed by a suitable means. The opposite end portion
33
d
of the central conductor
33
b
projected above the circuit board
34
is soldered to a circuit pattern by solder
37
.
As shown in
FIG. 14
, a short-circuit wall
38
is formed in a box shape using a metal such as die-cast aluminum or zinc and is secured to the circuit board
34
by a desired means, e.g., caulking, so as to cover the through holes
34
b
formed in the circuit board. A bottom portion
38
a
of the short-circuit wall
38
functions as a short-circuit portion for the probe
36
.
A cover
39
, which is constituted by a single rectangular metallic plate (see FIGS.
13
and
14
), is placed on the stepped portions
31
e
(see
FIG. 15
) of the side walls
31
b
of the housing
31
and is fixed by a suitable means. The receptacle portion
31
c
(see
FIG. 14
) of the housing
31
is hermetically sealed and the interior thereof is shielded electrically.
In the conventional converter for satellite broadcast reception, however, since the waveguide
32
and the holding portion
32
d
are formed integrally by die-casting aluminum for example, the material cost is high and it takes a considerable time for the manufacture, that is, the productivity is poor.
Besides, since the holding portion
32
d
is formed (see FIG.
15
), the mold used for die casting is complicated and expensive, thus giving rise to the problem that the converter becomes expensive.
Further, it is necessary that the insulating portion
33
a
of the probe
33
be press-fitted into the holding portion
32
d
of the waveguide
32
; besides, the press-fitting work is performed in the hollow portion
32
c
which is narrow. Consequently, a considerable time is required for the manufacture, that is, the productivity is poor.
SUMMARY OF THE INVENTION
It is an object of the present invention to provide a converter for satellite broadcast reception which is superior in productivity and inexpensive.
According to the first means adopted by the present invention for solving the above-mentioned problems there is provided a converter for satellite broadcast reception, comprising a box-shaped metallic housing, a cylindrical waveguide, and a probe attached to the waveguide, the probe having a cylindrical insulating portion and a central conductor piercing through a central part of the insulating portion, the waveguide being formed by bending a metallic plate and being integrally provided with a holding portion positioned outside the waveguide to hold the insulating portion of the probe.
According to the second solving means adopted by the invention, the insulating portion of the probe is held grippingly by both an outer surface of the waveguide and the holding portion.
According to the third solving means adopted by the invention, the holding portion is provided with a retaining piece for locking a free end side of the holding portion to the waveguide.
According to the fourth solving means adopted by the invention, the holding portion covers the probe throughout the whole in the longitudinal direction of the insulating portion which is exposed from the waveguide.
According to the fifth solving means adopted by the invention, the holding portion covers the probe throughout the whole in the longitudinal direction of the central conductor which is exposed from the waveguide.
According to the sixth solving means adopted by the invention, the insulating portion with the central conductor installed therein is formed with a slot in the longitudinal direction thereof, and one end portion of the central conductor is bent along the slot.
According to the seventh solving means adopted by the invention, an outer surface of the insulating portion of the probe includes a flat surface, and the probe is held by the holding portion in an abutted state of the flat surface against an outer surface of the waveguide.
According to the eighth solving means adopted by the invention, the flat surface formed as a part of the outer surface of the insulating portion is perpendicular to an extending direction of one end of the c
Alps Electric Co. ,Ltd.
Brinks Hofer Gilson & Lione
Lee Benny
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