JPS6012323Y2 - Lumped constant type circulator - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to a lumped constant circulator, and particularly to a lumped constant circulator having a built-in capacitor for frequency adjustment.

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 part 1, which is a combination of strip lines, sandwiched between two ferrite sheets, and a shield case 3 on the outside of the ferrite 2.
Permanent magnets 4 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 5 as junction inductors, as shown in FIG.

Usually, each strip line 5 is formed into a fork shape using a metal plate, insulated with an insulator, and then combined so as to intersect with each other in a net shape.

One end of the strip line 5 is connected to the input/output terminal 6, the other end is grounded to the shield case 3, and a frequency adjustment capacitor 7 is provided between the input/output terminal 6 side and the shield case 3. .

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

However, if the strip line 5 is made of a metal plate as shown in Fig. 2, the center conductor 1 must be manufactured manually, and the capacitor 7 must be externally attached, making it difficult to mass-produce. , miniaturization is also difficult.

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.

Hitherto, as a solution to this problem, a structure as shown in FIG. 3 or a structure disclosed in Japanese Patent Publication No. 33344/1983 by the present applicant has been proposed.

In this figure, conductor films 11A and IIB are formed by etching or the like on the upper and lower surfaces of an insulating substrate 10, respectively, by dividing the strip line 5A into two parts, and each set of conductor films 11A and IIB is electrically connected by a through hole 12. One stripline 5A is constructed by the above.

In this case, the insulation between each strip line 5A is performed by the insulating substrate 106. However, in the configuration shown in FIG. 3, the through holes 11 and 2
is indispensable, and a substrate with a certain thickness or more is required.
In the case of 0, the through hole 12 must be formed using vapor deposition, plating, etc., which makes it difficult to mass-produce the insulating substrate 1.
Since both sides of the substrate must be used, it is difficult to use the substrate surface for forming other elements.

The present invention eliminates the above-mentioned disadvantages, uses film fabrication technology to form a multilayer strip line on one side of an insulating substrate, and at the same time forms a capacitor for frequency adjustment on the insulating substrate, resulting in excellent mass productivity. The present invention aims to provide a lumped constant circulator that can be downsized.

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

In FIGS. 4 to 7, an insulating substrate 20 made of alumina, etc.
A shield case mounting hole 21 is provided in advance 4,
On one side of the insulating substrate 20, a first conductive film 22A in the shape of a strip line divided into two, which is to be a pair of conductive lines short-circuited at both ends, is screen-printed with a metal paste such as gold or silver and baked. It is formed by

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

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

Here, the insulating film 24 has a circular shape so as to cover the first conductive film 22A except for the peripheral end, and the insulating film 24
Since the tip portion 31A of the first conductive film 22A is exposed in the connection hole 23 of No. 4, the tip portion 31A of the first conductive film 22A and the conductive film 22B are exposed when forming the second conductive film 22B.
are joined to the tip portions 31B of the strip lines 5B, each having a capacitive 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 section 1A having three sets of strip lines 5B as center conductors is fully utilized, and the capacitive electrode 25 side end of each strip line 5B is connected to the input/output terminal 27.
The other end is grounded to the shield case, and the ground electrode 26 is also grounded to the shield case.

Note that the structure of other parts can be the same as that shown in FIG. 1.

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

1 The first and second conductive films 22A, 22B and the insulating film 24 are formed on one side of the insulating substrate using thick film technology, and since the insulating film 24 is thin, the connection hole 23 of the insulating film 24 can be The conductive films 22A and 22B can be easily connected.

2 Strip line 5 on one side of the dielectric insulating substrate
Capacitive electrode 25 for frequency adjustment integrally formed at the B end
A capacitor C for frequency adjustment can be formed between the ground electrode 26 and the ground electrode 26 on the other side of the insulating substrate.

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.

3. By changing the width of the capacitive electrode 25 for frequency adjustment, the capacitance C can be changed, and the frequency can be arbitrarily selected.

4. Since thick film technology is used, the cost is lower and mass production is better when considering scale, time, etc., than when using thin film technology during vapor deposition.

5. Since there is no need to process holes for through holes in the insulating substrate 20, there is no damage associated with processing the insulating substrate 20, and the finish is good.

6. As the insulating substrate 20 can be made of a material with a high dielectric constant, such as alumina, and excellent thermal conductivity, insulation, and temperature characteristics, safe performance can be obtained.

In addition, in the above embodiment, the case where the conductor film is constructed using thick film technology is shown as an example, but it may be constructed using thin film technology.

It is also clear that an isolator can be constructed by terminating one of the input/output terminals with a resistor.

As described above, according to the present invention, a strip line is formed on one side of an insulating substrate using film creation technology, and at the same time, a capacitor for frequency adjustment is formed on the insulating substrate, thereby combining conventional metal plates. It is possible to obtain a lumped constant type circulator which is superior in mass production and can be made smaller than the conventional through-hole type circulator shown in FIG.

[Brief explanation of the drawings] 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 conventional double-sided board diagram. FIG. 4 is a perspective view showing the structure of a strip line using the present invention, FIG. The figure is an exploded perspective view, and FIG. 7 is a sectional view taken along the line -■ in FIG. 4. 1... Center conductor, 1A... Center conductor part, 2... Ferrite, 3... Shield case, 4... Permanent magnet, 5.5A, 5B--
-----Strip line, 6.27... Input/output terminal, 10, 20... Insulated board, 11A, 1
1B, 22A, 22B... Conductor film, 23...
... Connection hole, 24 ... Insulator film, 25 ...
...capacitance electrode, 26...earth electrode, 31A
, 31B...Tip.

Claims (1)

[Scope of utility model registration request] In a lumped constant type circulator in which the central conductor section is constructed by intersecting at least three or more 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. forming a second conductive film 22B on the insulating film 24 or on the insulating film 24 and the insulating substrate 20;
the first and second conductor films 22A through the connection hole 23;
22B to form the center conductor section,
A ground electrode 26 is provided on the other surface of the insulating substrate 20, and a capacitive electrode 25 for frequency adjustment is provided with the first or second conductor film at a portion where the pair of conductive lines are short-circuited at a position opposite to the ground electrode. A lumped constant circulator characterized by being integrally formed with.