Non-reciprocal circuit device and communication apparatus

Details Non-reciprocal circuit device and communication apparatus Non-reciprocal circuit device and communication apparatus

2002-05-23

2004-04-20

Tokar, Michael (Department: 2819)

Wave transmission lines and networks

Plural channel systems

Nonreciprocal gyromagnetic type

C333S024200

Reexamination Certificate

active

06724276

ABSTRACT:

BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a non-reciprocal circuit device, such as an isolator, a circulator, or other suitable device, used in a microwave band and a communication apparatus including such a non-reciprocal circuit device.
2. Description of the Related Art
An example of a known lumped-constant-type isolator used in mobile communication apparatuses such as portable telephones, and other suitable communication apparatuses, is described in Japanese Unexamined Patent Application Publication No. 11-195912. As shown in
FIG. 12
, the isolator
200
includes a terminal resin case
202
, a lower metal case
208
, and an upper metal case
204
, and a permanent magnet and a central-electrode assembly provided in the terminal resin case, although not shown.
In
FIG. 12
, an input-output terminal
210
and a ground terminal
211
for surface mounting are provided on a side wall
202
a
on the front surface of the terminal resin case
202
. An input-output terminal and a ground terminal are also provided on a side wall
202
a
on the rear surface of the terminal resin case
202
, although not shown.
As shown in
FIG. 12
, the isolator
200
is produced using a lead frame
231
in order to facilitate handling of the product in production and automation of the production. The lead frame
231
is successively transported from one assembling process step to another via pilot holes
234
provided in each of a pair of hoop portions
233
. While the lead frame
231
is transported from one assembling process step to another, the ground terminal
211
and the input-output terminal
210
are insert-molded in the terminal resin case
202
. A connection portion
235
is provided on the bottom portion (side of the substrate for mounting the isolator
200
) of the side wall
202
a
of the terminal resin case
202
to facilitate mounting of components in later steps. Then, the components (upper metal case
204
and lower metal case
208
) of the isolator
200
are mounted, and the isolator
200
is assembled. The isolator
200
is separated from the lead frame
231
by stamping out the connection portion
235
, which connects the lead frame
231
with the isolator
200
and by using a cutting die.
However, as shown in
FIG. 12
, since the isolator
200
is separated from the lead frame
231
by stamping out the connection portion
235
provided on the side wall
202
a
of the terminal resin case
202
, burrs are produced on the cutting surface of the connection portion
235
. When these burrs are present, mounting conditions of the isolator
200
deteriorate because a gap caused by the burrs exists between the isolator
200
and the mounting substrate. For example, the mounting anchorage of the isolator deteriorates, and the terminals
210
and
211
are separated from the connection electrodes of the mounting substrate, which produces an open circuit.
Furthermore, since the terminals
210
,
211
and the connection portion
235
are provided on the side wall
202
a
of the terminal resin case
202
, the width of the input-output terminal
210
and the grounding terminal
211
is reduced because the connection portion
235
is provided on the side wall
202
a
, and the solder joint area of the mounting substrate and the input-output terminal
210
and grounding terminal
211
is reduced. Therefore, when the isolator
200
is mounted on a mounting substrate, the mounting anchorage of the input-output terminal
210
and grounding terminal
211
deteriorates.
SUMMARY OF THE INVENTION
In order to overcome the problems described above, preferred embodiments of the present invention provide a non-reciprocal circuit device which provides greatly improved mounting anchorage, reduced size, and outstanding reliability, and a communication apparatus including the non-reciprocal circuit device.
According to a preferred embodiment of the present invention, a non-reciprocal circuit device includes a permanent magnet, a ferrite member having a DC magnetic field provided by the permanent magnet and a central electrode assembly including a plurality of central electrodes arranged around the ferrite, a terminal resin case including the center electrode assembly, the terminal resin case having a first side surface defining a cutting surface when the terminal resin case is separated from a lead, input-output and ground terminals which are led out from a second side surface, different from the first side surface of the terminal resin case, and a metal case which includes the permanent magnet and the terminal resin case.
Accordingly, since the cutting surface, formed when separated from the lead frame, is provided on the first side surface of the terminal resin case and the input-output and grounding terminals are provided on the second side surface, which is different from the first side surface, of the terminal resin case, the width of the input-output and grounding terminals is greatly increased and the solder joint area of the substrate for mounting and each of the terminals is greatly increased.
Furthermore, preferably, a grounding electrode plate that is separated from the lead frame at the cut surface is integrally provided with the terminal resin case, and the grounding electrode plate extends to define the ground terminal. In this way, the ground potential of the grounding electrode plate integrally provided together with the ground terminal is reduced, and stray inductance which does not contribute to the operation of a non-reciprocal circuit device is minimized.
Furthermore, preferably, a concave portion is provided on the side surface of the terminal resin case, the cut surface is disposed in the concave portion, and the cut surface is covered by the metal case. In this way, when the non-reciprocal circuit device is separated from the lead frame, the positional accuracy for separation is less important. That is, even if the position for separation deviates slightly, the left portion is received in the concave portion and will not protrude outside of the dimensions of the non-reciprocal circuit device. Furthermore, even if burrs and metal chippings exist on the cut surface, the cut surface is still covered by the metal case, and thus, a short circuit and an open circuit are not caused.
Furthermore, preferably, an insertion hole is provided in the grounding electrode plate so as to insert the central-electrode assembly. That is, since a portion of the central-electrode assembly is included in the grounding electrode plate, the height of the non-reciprocal circuit device is reduced by the thickness of the grounding electrode plate.
Furthermore, since a communication apparatus according to the present invention includes a non-reciprocal circuit device according to preferred embodiments described above, a smaller, a less expensive and more reliable apparatus is provided.
Other feature, elements, characteristics and advantages of the present invention will become more apparent from the following detailed description of preferred embodiments of the present invention with reference to the attached drawings.


REFERENCES:
patent: 5223805 (1993-06-01), Talcott et al.
patent: 5620543 (1997-04-01), Marusawa et al.
patent: 5945887 (1999-08-01), Makino et al.
patent: 6462628 (2002-10-01), Kondo et al.
patent: 6512424 (2003-01-01), Furuya et al.
patent: 11-195912 (1999-07-01), None

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