JPS6110325Y2 - - Google Patents

Description

[Detailed Description of the Invention] (Industrial Application Field) The present invention relates to a lumped constant circulator.

(Prior Art) There are waveguide type and coaxial type circulators that operate as nonreciprocal 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 striplines, 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 inductors, as shown in FIG. Usually each stripline 6
are formed into fork-shaped metal plates, insulated with an insulator, and then combined so as to intersect with each other in a net shape. One end of the stripline 6 is connected to the input/output terminal 7, and the other end is connected to the shield case 3.
and is grounded to the storage case 4, and further a frequency adjustment capacitor 8 is provided between the input/output terminal 7 side and the shield case 3.

(Problems to be Solved by the Invention) Incidentally, as microwave equipment has become smaller in recent years, there has been a demand for smaller lumped constant circulators. However, the second
If the stripline 6 is made of a metal plate as shown in the figure, the center conductor 1 must be manufactured manually, which limits miniaturization and is not suitable for mass production. Furthermore, it is necessary to externally attach a capacitor 8 for frequency adjustment, which also poses an obstacle to miniaturization.

(Means for Solving the Problems) In view of the above points, the present invention uses film forming technology to form multilayer striplines on one side of an insulating substrate, and also reduces the capacitance at the intersection of the striplines. By using the capacitor for frequency adjustment, the present invention aims to provide a lumped constant type circulator that is small and excellent in mass production.

(Embodiments) Hereinafter, embodiments of the lumped constant circulator according to the present invention will be described with reference to the drawings.

In FIGS. 3 and 4, an insulating substrate 10 made of alumina or the like is provided with a shield case mounting hole 20 in advance, and a pair of conductive lines are first short-circuited at both ends on one side of the insulating substrate 10. A first conductor film 11A in the shape of a strip line divided into two is formed by screen printing and baking a metal paste such as gold or silver. next,
An insulator film 13 having a connection hole 12 at a position corresponding to the tip 21A of the first conductor film 11A is formed on the first conductor film 11A by screen printing and baking a dielectric paste such as glass. Ru. Then, a second conductive film 11B constituting the other half of the stripline is formed by screen printing and baking a metal paste onto the insulating film 1.
3 and partially on the insulating substrate 10. Here, the insulating film 13 has a circular shape so as to cover the first conductive film 11A except for the peripheral end, and the first conductive film 11A is formed in the connection hole 12 of the insulating film 13. Since the tip 21A of the second
When the conductor film 11B is removed, the tip 21A of the first conductor film 11A and the tip 21 of the second conductor film 11B are removed.
B are joined to form strip lines 6A, respectively.

By the way, as shown in FIGS. 5 and 6, at the intersection 30 of each stripline 6A,
The second conductor film 11 is applied to the first conductor film 11A on the insulating substrate 10 via the insulator film 13 that acts as a dielectric.
B overlaps, and the capacitance C of this portion functions equivalently as a frequency adjustment capacitor. In order to set this frequency adjustment capacitance to an appropriate value, a narrow capacitance adjustment portion 31 is formed in the second conductor film 11B located at each intersection portion 30.

As described above, the center conductor section 1A having three sets of striplines 6A as center conductors is completed, one end of each stripline 6A is led out to the input/output terminal 14, and the other end is connected to the shield case. grounded. In addition, ferrite is arranged above and below the center conductor portion 1A as in the case of FIG.
A shield case is provided to cover the ferrite, and a permanent magnet is further provided to apply a DC magnetic field to the ferrite.

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

(1) Since the capacitance adjustment part 31 is formed in the conductor film 11B located at the intersection 30 of the stripline 6A, by changing the width of this capacitance adjustment part 31, the frequency adjustment capacitance can be set to a desired value. . Therefore, there is no need to externally attach a frequency adjustment capacitor between the input/output terminal 14 and the ground, allowing for miniaturization, and it is easy to obtain the same characteristics when mass-produced.

(2) The first conductive films 11A, 11B and the insulating film 13 are formed on one side of the insulating substrate using film forming technology, and since the insulating film 13 is thin, the conductor can be passed through the connection hole 12 of the insulating film 13. The membranes 11A and 11B can be easily connected. Therefore, a circulator with excellent mass productivity can be obtained.

(3) As the insulating substrate 10 can be made of a material with a high dielectric constant, such as alumina, and excellent thermal conductivity, insulation, and temperature characteristics, stable performance can be obtained.

In the above embodiment, the capacitance adjustment section 31 is provided only in the upper second conductor film 11B, but the capacitance adjustment section may be provided in the lower first conductor film 11A if necessary. Furthermore, it is clear that an isolator can be constructed by terminating one of the input/output terminals 14 with a resistor.

(Effects of the invention) As explained above, according to the invention, a multilayer stripline is formed on one side of an insulating substrate using film forming technology, and the capacitance at the intersection of the striplines is reduced. By using it as a frequency adjustment capacitor, a lumped constant type circulator that is small and excellent in mass production is obtained.

[Brief explanation of the drawing]

Figure 1 is a schematic configuration diagram of a general lumped constant circulator, Figure 2 is a plan view showing the configuration of a conventional stripline as a center conductor, and Figure 3 is an implementation of the lumped constant circulator according to the present invention. As an example, FIG. 4 is a plan view showing the structure of the central conductor, FIG. 4 is an exploded perspective view, FIG. 5 is an enlarged view showing the stripline intersection, and FIG. 6 is a cross-sectional view of FIG. 5. . 1...Center conductor, 1A...Center conductor part, 2...
Ferrite, 3... Shield case, 4... Storage case, 5... Permanent magnet, 6, 6A... Strip line, 10... Insulating board, 11A, 11B...
...Conductor film, 12... Connection hole, 13... Insulator film,
14... Input/output terminal, 21A, 21B... Tip part, 30... Crossing part, 31... Capacity adjustment part.

Claims (1)

[Scope of utility model registration request] In a lumped constant type circulator in which a central conductor section is constructed 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 parts, A first conductor film 11A is formed on one side of the insulating substrate 10 on one side of each divided stripline, and an insulator film 13 having a connection hole 12 at a position corresponding to the tip of the first conductor film is formed on at least the first conductor film 11A. 1 conductive film 11B, and the remaining portions after dividing each stripline are formed on a second conductive film 11B.
is formed on the insulating film 13 or on the insulating film 13 and the insulating substrate 10, and the first and second conductive films 11A and 11B are connected through the connection hole 12 to form the center conductor part. At the same time, the first and second conductor films 11A and 11B are connected to the insulator film 13.
the first or second conductor film 1 located at the intersection 30 of the strip lines overlapping with each other through the
A lumped constant type circulator characterized in that a capacitance adjusting section 31 is formed in which the width of at least one of 1A and 11B is changed to be narrower.