JPH098509A - Lumped constant type isolator - Google Patents

Abstract

PURPOSE: To attain miniaturization and to improve power resistance by arranging a dummy resistor onto a side face of a case inner face. CONSTITUTION: A chip resistor (dummy resistor) 17 is soldered to a side face of a lower case 12. Two patterns of the chip resistor 17 connecting to a center conductor 5 are formed in the middle and a resistor pattern is formed between the patterns and a ground pattern and insulated by an over-glass. Furthermore, the rear side of the chip resistor 17 is formed entirely to be a conductor pattern and connected to the ground pattern at both sides of a throughhole on the side face. A terminal 6a extended from the center conductor 5 is coupled with a static capacitance forming electrode 9a formed to a dielectric board 7 and with the pattern of the chip resistor 17. The chip resistor 17 is formed by connecting two resistors in parallel, and the resistance of each resistor is 100ohms, and the combined resistance of parallel connection is 50ohms. Furthermore, a printed circuit board 13 with a ground electrode 14 formed thereon is connected to a lower side of the lower case 12.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a lumped element isolator used in VHF, UHF, microwave bands and the like.

[0002]

2. Description of the Related Art FIG. 5 is an exploded perspective view of an example of a conventional lumped constant type isolator. In this conventional example, the lower case 65
A dielectric substrate 63 having a pattern electrode formed thereon is disposed, and a central conductor portion including a garnet 64 and a central conductor 66 superposed in an insulated state is disposed in a hole formed in the dielectric substrate. A conductor is connected to a predetermined pattern electrode on a dielectric substrate, and is configured to cover an upper case 68 on which a magnet 67 is mounted. Reference numeral 69 of the dielectric substrate 63 denotes a dummy resistor, and reference numeral 70 denotes a ground electrode. A dummy resistor connected to this ground electrode terminates one terminal of the central conductor.

[0003]

In the conventional lumped constant isolator, the dummy resistor is formed by a resistor printed on the dielectric substrate. In this dielectric substrate, the heat dissipation is not good, other pattern electrodes for capacitance and ground are also formed, and there is no room in space,
The withstand power of the dummy resistor part is small and is at most 1
Only a power resistance of about W could be realized. Therefore, if the space is widened, it goes against the trend of miniaturization, which is good for applications with relatively low withstand power, but it is difficult to configure a small lumped constant isolator for applications with relatively high withstand power. there were. In view of the above, it is an object of the present invention to provide a lumped constant isolator that is small in size and has high withstand power.

[0004]

SUMMARY OF THE INVENTION The present invention is a lumped constant isolator in which a dummy resistor is disposed on the side surface inside the case. Further, the present invention is the lumped constant isolator, wherein the dummy resistor is a chip resistor printed on a substrate, and is fixed to the side surface of the case and grounded. The present invention is also a lumped constant isolator in which the dummy resistor is configured by connecting two resistors in parallel. The preferred configuration of the lumped constant isolator of the present invention is a case, a dielectric substrate, a garnet,
They are the central conductor, permanent magnet, and dummy resistor. The case is connected to the ground and is configured to wrap the entire isolator, and has an effect as a shield case, and is divided into upper and lower parts. The dielectric substrate forms a capacitance, is disposed on a case, and has a hole for accommodating garnet. The center conductor has at least three center conductors insulated from each other on the garnet, one end of which is connected to the capacitance, and the other end of which is grounded.
The permanent magnet is for applying a DC magnetic field to the garnet. The dummy resistor is arranged on the side surface of the case, and one central conductor is connected to it. Also, a ground plate may be placed between the case and the dielectric substrate, and under the case,
A printed circuit board for mounting may be arranged.

[0005]

According to the present invention, by arranging the dummy resistor on the side surface of the inner surface of the case, it is possible to effectively use the space without increasing the size of the dielectric substrate for forming the electrostatic capacity and to increase the withstand power. A dummy resistor can be configured. Further, by using the dummy resistor printed on the substrate, it is possible to form a thin type, and at the same time as fixing the substrate to the case, one end of the dummy resistor can be grounded. At this time, it is desirable to use an alumina substrate as the substrate, and this alumina substrate can form a dummy resistor having high heat dissipation and high power resistance. Of course, the substrate on which this dummy resistor is formed is the same as the dielectric substrate on which electrostatic capacitance is formed.
It's another. Further, by using a configuration in which two resistors are connected in parallel to each other, a dummy resistor having high power durability can be configured.

[0006]

FIG. 1 is an exploded perspective view showing the construction of an embodiment according to the present invention. The structure of this embodiment will be described. First, a nickel-plated upper case 1, a permanent magnet 2, a center conductor 3, a dielectric substrate 7, a ground plate 10, a nickel-plated lower case 12, and a printed circuit board 13 Have been. The center conductor 3 is formed by folding a center conductor 5 so as to enclose a disk-shaped ferrite core (garnet) 4, and the ends of the center conductor 5 are formed as terminals 6a, 6b, and 6c. Then, the ground plate 10 and the dielectric substrate 7 are placed on the lower case 12 in an overlapping manner, and the ferrite core 4 of the central conductor portion 3 is placed in the central hole 8 of the dielectric substrate 7. . On the side of this lower case,
The chip resistor 17 is soldered. FIG. 2 is a front view of the chip resistor 17, and FIG. In the chip resistor 17, two patterns 18 connected to the central conductor are formed in the center, and a resistance pattern 19 is formed between the pattern 18 and the ground pattern 20 and is insulated by overglass. Further, the back surface of the chip resistor 17 is a full-surface conductor pattern 21,
The ground patterns on both sides are connected by the side through holes 22. A terminal 6a extending from the central conductor 5 is provided with an electrode 9 for forming a capacitance formed on the dielectric substrate 7.
It is bonded to a and further to the pattern 18 of the chip resistor 17. This chip resistor is configured by connecting two resistors in parallel. Each is 100Ω, and is 50Ω in parallel connection. A printed circuit board 13 having a ground electrode 14 is formed on the lower side of the lower case 12.
Are joined. The terminal 6 extending from the central conductor 5
b and 6c are joined to the capacitance forming electrodes 9b and 9c formed on the dielectric substrate 7, and are further bent and folded back to the back side of the printed circuit board 13. A protruding piece 11 is also formed on the ground plate 10, and is further bent and folded back to the back side of the printed circuit board 13. A plan view of the back surface of the printed circuit board 13 is shown in FIG. On the back surface of this printed circuit board 13, terminals 6 extending from each central conductor 5 are provided.
An electrode portion 15 for connecting b and 6c and an electrode portion 16 for grounding are formed to enable fixing of each terminal and surface mounting. Then, the upper case 1 to which the permanent magnets 2 are fixed is fitted into the lower case 12 to constitute a lumped constant type isolator. With this configuration, a small isolator having an outer shape of 7 mm square can be configured.

In this embodiment, the lumped-constant type isolator for 800 MHz has an insertion loss of 0.7 dB, an isolation of 15 dB, and a power withstand capability of 2 W. Further, in the same configuration as the present invention, a 7 mm square 1.
This is a lumped-constant isolator for 9 GHz, with an insertion loss of 0.6 dB, an isolation of 15 dB, and a characteristic of withstand power of 2 W.

In the present invention, the chip resistor can be fixed to the case by soldering, and the chip resistor can be fixed, and the dummy resistor can be grounded at the same time. In addition, by using the side of the case that has not been used in the past, it is possible to configure a larger dummy resistor inside the lumped-constant isolator than before, and it has much higher heat dissipation than that formed on a conventional dielectric substrate. By arranging the chip resistor on the alumina substrate, a dummy resistor with high power resistance could be constructed. In addition, the lumped constant type can be performed with a small size. Further, in the above embodiment, the lumped constant type isolator of 7 mm square is constructed, but the present invention is particularly effective for a small sized lumped constant type isolator (10 mm square or less).

[0009]

According to the present invention, it is possible to obtain a small lumped-constant type isolator having a large withstand power and a very effective protection for an amplifier, for example, in a cellular phone or the like by increasing the anti-reflection power due to mismatching. is there.

[Brief description of drawings]

FIG. 1 is a structural exploded perspective view of an embodiment according to the present invention.

FIG. 2 is a front view of a one-chip resistor according to the present invention.

FIG. 3 is a rear view of the one-chip resistor according to the present invention.

FIG. 4 is a plan view of the back surface of the printed circuit board according to one embodiment of the present invention.

FIG. 5 is an exploded perspective view of a conventional example.

[Explanation of symbols]

 1 Upper Case 2 Permanent Magnet 3 Center Conductor 4 Ferrite Core 5 Center Conductor 6 Terminal 7 Dielectric Substrate 9 Capacitance Forming Electrode 10 Earth Plate 12 Lower Case 13 Printed Circuit Board 17 Chip Resistor

Claims (3)

[Claims] 1. A lumped constant isolator, wherein a lumped constant isolator is provided with a dummy resistor on a side surface inside a case. 2. The dummy resistor according to claim 1,
A lumped-constant isolator, which is a chip resistor printed on a substrate and is fixed to the side surface of the case and grounded. 3. The lumped constant isolator according to claim 1, wherein the dummy resistor is configured by connecting two resistors in parallel.