JP3788790B2 - Non-reciprocal circuit element - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a nonreciprocal circuit device used as an isolator / circulator.
[0002]
[Prior art]
FIG. 9 shows an exploded perspective view of an example of a lumped constant type isolator as an example of a conventional non-reciprocal circuit device. In this conventional example, a dielectric substrate 63 on which a pattern electrode is formed is disposed on a lower case 65, and a central conductor portion made up of a ferrite 64 and a central conductor 66 that is overlapped in an insulated state is formed on the dielectric substrate. The center conductor and a predetermined pattern electrode on the dielectric substrate are connected to each other and covered with an upper case 68 on which a magnet 67 is mounted. 69 of the dielectric substrate 63 is a dummy resistor, and 70 is a ground electrode. One terminal of the central conductor is terminated by a dummy resistor 69 connected to the ground electrode.
[0003]
[Problems to be solved by the invention]
Since conventional lumped constant isolators are used for mobile phones, for example, there is a strong demand for miniaturization and thinning. Of course, it is required to have electrical characteristics that can withstand use and to be inexpensive. Considering this miniaturization, the outer diameter of the ferrite 64 is required to some extent in order to obtain desired electrical characteristics, and there is a limit to the miniaturization of the ferrite 64. Therefore, when the entire size is reduced, the hole 72 into which the ferrite is inserted becomes relatively large as shown in FIG. As a result, a weakly strong portion 71 is formed on the dielectric substrate, which increases the risk of the substrate being cracked during handling in the production process and lowers mass productivity. For this reason, it is difficult to reduce the size of the conventional structure. The dummy resistor is formed by a resistor printed on a dielectric substrate. In this dielectric substrate, heat dissipation is not good, and other electrostatic capacity and ground pattern electrodes are also formed, so there is no room in terms of space. For this reason, the power resistance in the dummy resistance portion is small, and only a power resistance of about 1 W can be realized. Therefore, if the space is expanded, the size of the device is reversed against the trend of miniaturization, and it is difficult to construct a small lumped constant isolator for applications that require a relatively large power resistance. In view of the above, it is an object of the present invention to provide a nonreciprocal circuit device that is small in size and has high power durability.
[0004]
[Means for Solving the Problems]
The present invention provides a resin case provided with a connection terminal, a center conductor portion in which a center conductor is arranged crossing a ferrite core between a metal case and a metal case, a capacitor, and a resin mold for positioning the ferrite core. The resin mold has a rectangular outer shape, is substantially the same size as the inside of the region defined by the side surface of the lower case and the side surface of the resin case, and is substantially the same as the outer periphery of the ferrite core in the center as well as have a formed to a size through-holes, from one side of the ferrite core of the center conductor bent center conductor to the cross side, the portion in the center conductor portion of the ferrite core side, the positioning of the ferrite core A surface that has a claw portion to be provided, does not have a claw portion at a portion located at the front end portion of the center conductor, and is connected to the front end portion of the center conductor of the capacitor The connection terminal is substantially the same height, with it, a nonreciprocal circuit device, characterized in that it connects the center conductor tip and the connecting terminal and the capacitor. In the present invention, it is preferable that the central conductor portion is disposed above the metal case, and the central conductor surrounding the ferrite core is grounded to the metal case.
[0005]
BEST MODE FOR CARRYING OUT THE INVENTION
An exploded perspective view of an embodiment according to the present invention is shown in FIG. This embodiment will be described. First, there is a resin case 1 at the bottom. A plan view and a side view of the resin case 1 in three directions are shown in FIG. 2, and a bottom view is shown in FIG. 2 and 3, the conductor portion is indicated by hatching. 2 is a sectional view taken along the line AA ′ of FIG. 2 and FIG. 5 is a sectional view taken along the line BB ′ of FIG. In the resin case 1, three conductor plates are formed integrally with the resin portion. This one conductor plate is a ground electrode plate 2, which is widely arranged at the bottom of the resin case 1, and a ground terminal 3 connected thereto is led out to the back surface serving as a mounting surface of the resin case 1. The other two conductor plates are for input / output terminals, and are U-shaped conductor plates in which the inner circuit connection terminal 4 and the outer input / output terminal 5 are connected. The inner circuit connection terminal 4 has a protrusion 6 formed on the surface on which the ground plate electrode 2 is disposed, and is disposed on the protrusion 6.
[0006]
A metal case lower 7 is placed on the resin case 1. The lower metal case 7 has a notch 8 corresponding to the protrusion 6 of the resin case 1 and is soldered to the ground electrode plate 2 of the resin case 1. On the lower metal case 7, the plate capacitor 9 having electrodes formed on the upper and lower surfaces of the dielectric plate, the chip resistor 10, and the central conductor 12 on the ferrite core 11 are insulated from each other at intervals of 120 degrees. A central conductor portion disposed in a rotationally symmetrical manner is disposed. As shown in FIG. 6, the center conductor portion is composed of two conductors each extending radially from the disc portion 14 at intervals of 120 degrees, and is composed of three center conductors 12 connected at the tips. The ferrite core 11 is disposed on the portion 14, each center conductor 14 is bent, and an insulating sheet is sandwiched between the center conductors. Of the three central conductors 12, the tip portions 13a and 13b of the two central conductors 12 are connected to the plate-like capacitor 9 and the inner circuit connection terminal 4 on the resin case 1, respectively, and the other central conductor 12 The tip portion 13 c is connected to the plate capacitor 9 and the chip resistor 10. The disk portion 14 of the central conductor portion is connected to the lower metal case 7 and is grounded. The plate capacitor 9 is also connected to the lower metal case 7 on the opposite side of the surface to which the tip of the central conductor is connected, and is grounded.
[0007]
A plan view, a side view, and a bottom view of the chip resistor 10 are shown in FIG. The chip resistor 10 has two terminal electrodes 15 and 16 on one surface, and a resistance film 17 made of ruthenium oxide is formed between the terminal electrodes. An insulating coat is applied on the resistance film. One terminal electrode 16 is electrically connected to the terminal electrode 18 on the bottom surface via the electrode 19 formed on the side surface. The front end portion 13c of one central conductor is connected to the terminal electrode 15 of the chip resistor 10, and the terminal electrode 18 of the chip resistor 10 is connected to the lower metal case 7 and grounded.
[0008]
Next, the resin mold 20 is put on the central conductor portion. The resin mold 20 has a through hole 21 having a size substantially equal to the outer diameter of the ferrite core at the center, and three claw portions 22 that are in contact with the outer peripheral portion of the ferrite core 11 at the lower portion. The pawl portion 22 is positioned at the central conductor portion on the side surface of the ferrite core, and performs positioning of the ferrite core and also serves as protection and insulation for the central conductor on the side surface of the ferrite core. The resin mold 20 has a size that allows the outer shape to be accommodated inside the resin case 1 and the lower metal case 7, and a protrusion 23 for positioning the magnet 24 is formed on the upper surface. And the magnet 24 is arrange | positioned in the position positioned by this protrusion part 23. FIG. And the metal case upper part 25 was covered, and the metal case upper part 25 and the metal case lower part 7 were soldered, and the nonreciprocal circuit element was comprised. One opposing surface 26 on the side surface of the upper metal case 25 is inserted inside the side surface 28 of the lower metal case 7 and soldered. The other facing surface 27 is located on the upper end of the side surface 29 of the resin case 1. This embodiment is a lumped constant type isolator, and a perspective view thereof is shown in FIG.
[0009]
In the above embodiment, one of the central conductors 12 is connected to the chip resistor 10 and terminated, so that it is an isolator. However, if the central conductor is not terminated and used as an input / output terminal, it is used as a circulator. I can do it.
[0010]
In the embodiment of the present invention, the height of the protrusion 6 on which the inner circuit connection terminal 4 of the resin case 1 is formed is substantially the same as that of the plate capacitor 9, and the connection between the tip portions 13 a and 13 b of the center conductor 12 is performed. Easy going. Further, the projection 6 ensures the insulation between the connection terminal 4 and the ground electrode plate 2. Further, the resin case 1 enables surface mounting. In the chip resistor 10 of the present invention, one terminal electrode 16 is led out to the bottom surface through the side surface, and the terminal electrode 18 is formed on the bottom surface. The terminal electrode 18 directly connects the bottom surface on the lower metal case 7. Since it is connected, it is connected to the bottom of the metal case over a wide area, has high heat dissipation, and is easy to connect. With improved heat dissipation, power durability can be improved. In the embodiment of the present invention, since the ferrite core and the magnet are positioned by one resin mold, the positioning is easy and the mounting is also easy. Further, since the claw portion of the resin mold covers the center conductor on the side surface of the ferrite core, a short circuit between the center conductor on the side surface of the ferrite core and the plate capacitor is prevented. According to the structure of this embodiment, even if the size of the ferrite core is relatively large, a dielectric substrate having a hole as in the prior art is not used, so that downsizing can be achieved.
[0011]
【The invention's effect】
According to the present invention, it is possible to obtain a lumped constant isolator that is small in size and has high power resistance, and is extremely effective for protecting an amplifier due to an increase in reflection power resistance due to mismatching in, for example, a mobile phone.
[Brief description of the drawings]
FIG. 1 is an exploded perspective view of an embodiment according to the present invention.
FIG. 2 is a plan view and a side view of a resin case according to an embodiment of the present invention.
FIG. 3 is a bottom view of a resin case according to an embodiment of the present invention.
4 is a cross-sectional view taken along line AA ′ of FIG.
FIG. 5 is a cross-sectional view taken along the line BB ′ of FIG.
FIG. 6 is a plan view of a central conductor according to an embodiment of the present invention.
7 is a plan view, a side view, and a bottom view of a chip resistor according to an embodiment of the present invention. FIG.
FIG. 8 is a perspective view of an embodiment according to the present invention.
FIG. 9 is an exploded perspective view of a conventional example.
FIG. 10 is a plan view of a conventional dielectric substrate.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Resin case 2 Ground electrode plate 3 Ground terminal 4 Inner circuit connection terminal 5 Input / output terminal 6 Protrusion part 7 Metal case bottom 8 Notch part 9 Plate-like capacitor 10 Chip resistor 11 Ferrite core 12 Center conductor 13a, 13b, 13c Tip part 14 Disc parts 15, 16, 18 Terminal electrode 17 Resistive film 19 Electrode 20 Resin mold 21 Through hole 22 Claw part 23 Projection part 24 Magnet 25 Metal case top 26, 27 Opposing faces 28, 29 Side face

Claims (2)

Between the resin case with the connection terminal and the metal case under and on the metal case, a center conductor portion in which the center conductor is arranged crossing the ferrite core, a capacitor, and a resin mold for positioning the ferrite core,
The resin mold has a rectangular outer shape,
It is approximately the same size as the inside of the region defined by the side surface of the lower case and the side surface of the resin case,
And thereby it has a through hole formed in substantially the same size as the outer periphery of the ferrite core to the center,
The center conductor bent from one side of the ferrite core to the center conductor crossing side has a claw for positioning the ferrite core at the center conductor on the side of the ferrite core, and is positioned at the tip of the center conductor. The part that does not have a claw part,
The surface connected to the center conductor tip of the capacitor and the connection terminal are substantially the same height.
Thus, the nonreciprocal circuit device is characterized in that the center conductor tip is connected to the capacitor and the connection terminal .   2. The nonreciprocal circuit device according to claim 1, wherein the center conductor portion is disposed under the metal case, and the center conductor enclosing the ferrite core is connected to the ground under the metal case.

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