Electrical connectors – Including or for use with coaxial cable – Having means for interconnecting outer conductors of three...
Utility Patent
1997-10-29
2001-01-02
Bradley, Paula (Department: 2833)
Electrical connectors
Including or for use with coaxial cable
Having means for interconnecting outer conductors of three...
C439S885000, C439S944000, C439S048000, C174S059000, C174S050510
Utility Patent
active
06168465
ABSTRACT:
BACKGROUND OF THE INVENTION
(1) Field of the Invention
The present invention relates to a universal low noise blockdown converter (LNB) which is known as a receiver-side converter for receiving a radio wave signal transmitted from broadcasting or communication satellites and converting it to a first intermediate-frequency signal in order to output the converted signal to a next step or a tuner circuit. More particularly, the present invention is directed to a terminal structure for output terminals to be used for various appliances inclusive of such converters.
(2) Description of the Prior Art
In recent years, there has been a world-wide trend of the rapid popularization of the satellite broadcasting to the general public. In harmony with this tendency, many proposals have been presented as to receiver-side converters which are to be used together with a satellite broadcasting receiving antenna. Examples of the latest receiver-side converters include various types such as LNBs (low noise blockdown converter) capable of receiving wide-band frequencies, LNBs for receiving both horizontally and vertically polarized waves, LNBs for receiving both right-handed and left-handed polarized waves. Any of these needs an increased number of terminals. These LNB converts for general use are called universal LNBs.
Now, let us consider the popularization tendency of satellite broadcasting in various countries and areas. In the European countries, the analog broadcasting via satellites, Astra (1A/1B/1C) had played a central role until recently. After Astra 1D was launched in 1994, the digital broadcasting was commenced experimentally, from January 1995. Satellite Astra 1E in October 1995 and satellite Astra 1F in the end of 1995 will be launched so as to establish the full-scale digital broadcasting market. Throughout Europe, there have been some 57 million subscribers, including both the direct receiving and indirect receiving subscribers, as of the end of 1994. Therefore, the market demands, by the commence of the digital broadcasting, the development of an LNB which has a broadened band range and is still highly stabilized so as to cover both the frequency bands.
In the American market, after the digital broadcasting was started on a full-scale from the middle of 1994, one million some hundred thousand subscribers have increased every year. Further, several programs of launching digital broadcasting satellites are scheduled by new companies. Accordingly, there is a strong demand of developing an LNB which has a broadened band range with a highly stabilized characteristic and is still inexpensive.
Turning to the Japanese market, digital broadcasting using the JCSAT is scheduled to start from the spring of 1996. In the first half of 1997, digital broadcasting using the Superbird is planned to commence. Thereby, there is an expectation that demand on an LNB which is able to receive both the digital satellite broadcasting and the digital broadcasting via CS will be increased.
Next, a typical receiver-side converter of this kind will be described with reference to drawings disclosed in Japanese Patent Application Laid-Open Hei 5 No.267,903.
FIG. 1
is a partially cutaway perspective view showing a typical receiver-side LNB converter used together with a BS antenna. As shown in
FIG. 1
, this configuration is composed of: a converter body
21
; a circular waveguide
121
joined to a horn (a primary radiator)
120
; a rectangular waveguide
122
which is integrally formed with the circular waveguide so as to extend perpendicular thereto; a base
123
, typically made of tetra-fluoroethylene resin, attached so that the body is sandwiched at a predetermined position of the circular waveguide
121
; a microstrip circuit board
124
formed on the surface of the base; an earthed surface
125
formed underside of the base
123
and constituting the upper surface of the rectangular waveguide; a first probe
126
projected from the inner surface of the circular waveguide
121
to detect horizontally polarized waves; and a second probe
127
projected from the inner surface of the rectangular waveguide
122
to detect vertically polarized waves.
In the LNB converter having the thus configuration as shown in
FIG. 1
, a matching reflection rib
128
for reflecting only the vertically polarized waves, by deflecting them 90° toward the second probe
127
is formed at the corner at which the circular waveguide
121
and the rectangular waveguide
122
are joined. The converter body
21
has a backside lid
129
so that the built-in microstrip circuit board
124
may be shielded from unnecessary radiation signals and the like. A terminal
22
which is connected to an unillustrated coaxial cable plug so as to allow the signal to output from the receiver-side LNB converter is fixed at one end of the converter body using a terminal base
119
with screws
24
.
Designated at
130
is a short-circuited end surface for reflecting horizontally polarized waves. This will be described later.
As a terminal structure for the receiver-side converter of this kind, the following configuration has been known.
FIG. 2A
is a sectional side view partially showing the terminal structure of the conventional receiver-side converter and
FIG. 2B
is a bottom view of the same. This terminal structure includes a plurality of output terminals
22
, each of which is securely attached by screws
24
to the converter body
21
with a hermetically sealing O-ring
23
therebetween. As shown in
FIG. 3
, each output terminal
22
is composed of a single unit in which an outer conductor
22
a
(to be called a shell, hereinbelow) of a metal with an assembly part
22
b
fixed therein by squeezing or press-fitting. This assembled part
22
b
is made of a laminate of a resin cap
25
, a resin base
26
and a metallic contact
27
.
FIGS. 4A and 4B
show another example of a terminal structure of the conventional receiver-side converter.
FIGS. 4A and 4B
are partial sectional side view and bottom view, respectively. In this configuration, a plurality of output terminals
31
are screwed into corresponding, tapped holes
32
formed on the converter body
21
by machining process. A low cylindrical wall
33
projected from the outside surface of the converter is provided for each output terminal
21
and a hermetically sealing agent
34
is filled therein.
FIGS. 5A and 5B
show a recently used configuration of a terminal structure in which a plurality of shells
22
a
for terminals
22
, spaced at intervals of a center distance
1
, are integrally formed with the converter body
21
.
FIGS. 5A
and
5
B are assembled and decomposed views, respectively. As seen in
FIGS. 5A and 5B
, an inner-terminal assembly part
22
b
is inserted into each shell
22
a
with an anti-falling press-ring
47
attached on the outer end. Outside peripheral of the shell
22
a
is threaded so that a coaxial cable plug, mentioned later, may be connected. In this figure,
48
designates a rubber sleeve for protecting the terminal
22
while
49
is a grease applied to the inner surface of the rubber sleeve.
In the above conventional terminal structure shown in
FIGS. 2A and 2B
, when a plurality of output terminals are attached to the converter body, the hermetically sealing O-ring must be fitted into each of the output terminals and then the output terminals should be secured with a pair of screws. Therefore, this structure requires much time and labor in assembling, resulting in an increased cost. Further, each output terminal must be assembled by squeezing the assembly part into the metallic shell. This structure limits the improvement of the manufacturing efficiency.
In the conventional configuration shown in
FIGS. 4A and 4B
, a tapped hole
32
should be formed for each output terminal in the converter body. Accordingly, the augment of the number of the output terminals means the increment of the number of the tapped holes
32
to be machined, so that the increment in the number of the output terminals is directly linked with increase of the cost for the unit.
In th
Bradley Paula
Sharp Kabushiki Kaisha
Ta Tho D.
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