JPS6042482Y2 - Lumped constant type circulator - Google Patents

Description

[Detailed explanation of the idea] The present invention relates to a lumped constant circulator.

There are waveguide type and coaxial type circulators that operate as non-reciprocal circuit elements in the microwave band, and there are two types of coaxial circulators: distributed constant type and lumped constant type.

Distributed constant type circulators are normally used in the high frequency range even in the microwave band, and lumped constant type circulators are used in the low frequency range.

FIG. 1 shows a schematic configuration of a general lumped constant type circulator.

In this figure, the lumped constant type circulator has a central conductor 1, which is a combination of strip lines, sandwiched between two ferrites 2, the outside of the ferrites 2 being wrapped in a shield case 3, and these are housed in a storage case 4. Permanent magnets 5 are provided above and below the shield case 3 to apply a DC magnetic field to the ferrite 2.

Here, the center conductor 1 is a combination of three sets of strip lines 6 as junction inductances, as shown in FIG.

Usually, each strip line 6 is formed of a metal plate in the shape of a fork, is insulated with an insulator, and then combined so as to intersect with each other in a net shape.

One end of the strip line 6 is connected to the input/output terminal 7, the other end is grounded to the shield case 3 and the storage case 4, and a frequency adjustment capacitor 8 is connected between the input/output terminal 7 side and the shield case 3. is provided.

Incidentally, in recent years, with the miniaturization of microwave equipment, there has been a demand for miniaturization of circulators.

However, if the strip line 6 is made of a metal plate as shown in Fig. 2, the center conductor 1 must be manufactured manually, which limits miniaturization and is not suitable for mass production. be.

For this reason, it has been considered to form a stripline pattern on an insulating plate using thick film or thin film technology, but insulation at the intersections of each stripline becomes a problem.

To solve this problem, a structure as shown in FIG. 3 or a structure disclosed in Japanese Patent Publication No. 48-33344 by the present applicant have been proposed.

In FIG. 3, conductor films 11A and 11B are formed by etching or the like on the upper and lower surfaces of an insulating substrate 10, respectively, by dividing the strip line 6A into two parts, and each set of conductor films 11A and 11B is electrically connected by a through hole 12. They are connected to form one stripline 6A.

In this way, strip lines 6 are formed on the upper and lower surfaces of the insulating substrate 10.
In the center conductor portion 1A in which the strip lines 6A are formed, insulation between the strip lines 6A is provided by the insulating substrate 10.

However, in the configuration shown in FIG. 3, the through hole 12 is essential, and in the case of the insulating substrate 10 having a certain thickness or more, the through hole 12 must be formed using vapor deposition, plating, etc. There is a disadvantage that mass production is poor and both sides of the insulating substrate 10 must be used.

Further, problems arise in the arrangement of the ferrite on the upper and lower surfaces of the central conductor portion IA and in the mounting structure of the shield case.

The present invention solves the above problems by forming a multilayer strip line on one side of an insulating substrate using film production technology, and forming a slit for fixing the shield case at the ground side end of the strip line. The present invention aims to provide a lumped constant type circulator that is compact, easy to assemble, and excellent in mass production.

Embodiments of the lumped constant circulator according to the present invention will be described below with reference to the drawings.

FIGS. 4 and 5 show a first embodiment of the present invention, in which a circulator is constructed.

In these figures, the central conductor portion IB is formed by thick film technology on one side of an insulating substrate 20 with a strip line 6B having a configuration in which a pair of conductive lines are short-circuited at both ends.

Ferrite 2 is disposed above and below this central conductor portion IB, and a shield case 3A is attached to cover the ferrite 2, and these are housed in a storage case 4A.
A permanent magnet 5 receives a direct current magnetic field.

Now, in the center conductor portion 1B, as shown in FIGS. 5 and 6, an insulating substrate 20 made of alumina or the like has a mounting slit 21 formed in advance so as to pass through the substrate.
First, a strip line 6B is formed on one side of the insulating substrate 20.
A first conductor film 22A having a shape of dividing into two is formed by screen printing and baking a metal paste such as gold or silver.

Next, an insulator film 24 having a connection hole 23 at a position corresponding to the tip 31A of the m-th conductor film 22A is formed on the first conductor film 22A by screen printing and baking a dielectric paste such as glass. is formed.

Then, a second conductive film 22B, which is the remaining half of the strip line 6B and which integrally has a capacitive electrode 25 for frequency adjustment, is formed on the insulating substrate 20 and the insulating film 24 by screen printing and baking a metal paste. Ru.

Here, the insulating film 24 has a circular shape that covers the first conductive film 22A except for the peripheral part, and the insulating film 24
The tip 3 of the first conductor film 22A is located in the connection hole 23 of the
1A is exposed, the tip 31 of the first conductive film 22A and the second conductive film 22 are exposed when forming the second conductive film 22B.
The strip lines 6B are joined to the tip portions 31B of B, and each strip line 6B has a capacitor electrode 25 at its end.

Further, on the other surface of the insulating substrate 20, a ground electrode 26 is formed on the entire surface except for the portion where the ferrite is located by screen printing and baking a metal paste.

In this way, the center conductor part IB having three sets of strip lines 6B as the center conductor is completed, the capacitor electrodes 25 of each strip line 6B are drawn out as input/output terminals 27, and the other end is connected to the shield case 3A. It is along the mounting slit 21 for mounting.

Disc-shaped ferrites are arranged above and below the center conductor portion IB, respectively, so as to sandwich the center conductor portion IB.

The shield case 3A integrally has a mounting leg 28 that fits into the slit 21.

Therefore, as shown in FIG. 7, the upper and lower shield cases 3A are inserted and fixed into the mounting slit 21 of the center conductor part IB while covering and holding the ferrite 2, and the ground side end of the strip line 6B is soldered etc. connected to.

In this case, the connection between the ground electrode 26 and the ground side end of the strip line 6B is also made at the same time via the mounting leg 28 of the shield case 3A.

On the other hand, in the portion of the strip line 6B where the capacitive electrode 25 is provided, no slit is provided as shown in FIG. 8, and a capacitor C is formed between the capacitive electrode 25 and the ground electrode 26.

According to the above embodiment, the following effects can be achieved.

(1) A mounting slit 21 is formed in order to attach the shield case 3A to the insulating substrate 20, and the slit 21
is located at the ground side end of the strip line 6B, making it easy to attach the ferrite 2 and the shield case 3A, and the connection between the shield case 3A and the ground electrode 26 of the strip line 6B1 is automatically established. It is easy to assemble and mass-producible.

Note that when alumina is used as the insulating substrate 20, the slit 21 can be easily formed by press working before firing.

(2) The first and second conductor films 22A are formed using film formation technology.

22B and the insulating film 24 are formed on one side of the insulating substrate, and since the insulating film 24 is thin, it is easy to connect the conductive films 22A and 22B through the connection hole 23 of the insulating film 24.

Therefore, a circulator with excellent mass productivity can be obtained.

(3) Capacitive electrode 2 for frequency adjustment integrally formed at the end of the strip line 6B on one side of the dielectric insulating substrate
5 and the other ground electrode 26 of the insulating substrate, a capacitor C for frequency adjustment can be formed.

Therefore, a capacitor for frequency adjustment is connected to the input/output terminal 27.
There is no need to externally connect the device between the device and the ground, making it possible to downsize the device, and when mass-producing it, it is easy to obtain the same characteristics.

(4) The insulating substrate 20 has a high dielectric constant such as alumina,
Stable performance can be achieved because materials with excellent thermal conductivity, insulation, and temperature characteristics can be used.

FIG. 9 shows a second embodiment of the present invention, in which an isolator is configured with one end of a circulator terminated.

In this figure, the strip line 6B of the insulating substrate 10
A termination resistive film 40 serving as a terminator is formed between the capacitive electrode 25 side of the strip line 25 and the ground side end of the adjacent strip line 6B by screen printing and baking a resistive paste.

Note that the other configurations are the same as those of the first embodiment described above.

According to this second embodiment, it is possible to downsize the isolator, simplify the assembly work, and improve mass productivity.

As described above, according to the present invention, a multilayer strip line is formed on one side of an insulating substrate using film fabrication technology, and a slit for fixing the shield case is formed at the ground side end of the strip line. Therefore, it is small and easy to assemble, and the structure of the center conductor part and the mounting structure of the shield case are suitable for mass production, compared to the conventional structure combining metal plates or the conventional structure using through holes as shown in FIG.

[Brief explanation of the drawing]

Figure 1 is a schematic configuration diagram of a general lumped constant type circulator, Figure 2 is a plan view showing the configuration of a conventional strip line as a center conductor, and Figure 3 is a diagram of a conventional center conductor using both sides of the board. Fig. 4 is a cross-sectional view showing the overall structure of the first embodiment of the lumped constant circulator according to the present invention; Fig. 5 is an exploded perspective view of the main parts; Fig. 6 is a center view. Figure 7 is a partial cross-sectional view showing the mounting structure of the shield case on the grounding side of the strip line, Figure 8 is a partial cross-sectional view of the non-grounding side of the IJ tube line, and Figure 9 is a partial cross-sectional view of the non-grounding side of the IJ tube line. FIG. 7 is an exploded perspective view showing a second embodiment. 1... Center conductor, IA, IB, IC...
・Center conductor part, 2*e****ferrite, 3,3A・
...Shield case, 4,4A...Storage case, 5...Permanent magnet, 6,6A----
- Strip line, 10, 20... Insulating board, 21... Mounting slit, 22A, 22B.
...Conductor film, 23...Connection hole, 24...
... Insulator film, 25 ... Capacitor electrode, 26.
...Earth electrode, 28...Mounting leg, 40
...Resistive film.

Claims (1)

[Scope of utility model registration request] In a lumped constant circulator in which a central conductor section is formed by intersecting at least three striplines formed by short-circuiting a pair of conductive lines at both ends, each stripline is divided by a pair of conductive line sections, and each One side of the divided strip line is formed on one side of the insulating substrate 20 with a first conductive film 22A, and an insulating film 24 having a connection hole 23 at a position corresponding to the tip of the first conductive film is formed on at least the first conductive film 22A. The remaining parts after dividing each strip line are formed on the insulating film 24 or on the insulating film 24 and the insulating substrate 20 with a second conductive film 22B, and the connection is made. The first and second conductor films 22A are inserted through the holes 23.
. The ferrite 2 is arranged above and below the center conductor part, the ferrite 2 is covered with a shield case 3A, and the mounting leg 28 of the shield case 3A is fitted into the slit 21 to connect the first or second conductor film. A lumped constant type circulator, characterized in that it is connected to the ground side end.