JPH0662605U - Lumped constant type circulator - Google Patents

Abstract

(57) [Abstract] [Purpose] Eliminates the space created between adjacent parts such as ferrite, center conductor, ground conductor, and insulator, and eliminates the work of adjusting the value of the tuning capacitor connected to each terminal, facilitating assembly. To provide a lumped constant type circulator. [Structure] The insulating material for insulating between the central conductors is made of ceramic, and the central conductor, the insulating material, and the ferrite are
Ferrite 12a, first center conductor 11a, first insulator 14a, second center conductor 11b, second insulator 14
b, the third central conductor 11c, and the second ferrite 12b are stacked in this order, and these are directly joined by the DBC technique.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to a lumped constant type circulator used in microwave communication equipment such as an amplifier, an oscillator, and a transceiver.

[0002]

[Prior art]

 Circulators used in microwave communication devices such as amplifiers and oscillators are classified into lumped constant type and distributed constant type based on their circuit constant classification.

Since the lumped constant type can be miniaturized, it is widely used in a relatively low frequency range from the VHF band to the 2 GHz band.

The three-terminal circulator is also used as an isolator by matching-terminating one of its terminals.

Here, a conventional three-terminal lumped constant circulator will be described with reference to the exploded view of FIG.

Reference numerals 41a, 41b, and 41c are reticulated center conductors (hereinafter, simply referred to as center conductors) each having a plurality of, for example, two branches.

The three central conductors 41a, 41b, 41c intersect each other at an angle of approximately 120 degrees in the same plane. The center conductors 41a, 41b, 41c are insulated from each other, and two sets of ferrites 42a, 42b and ground conductors 43a, 43b are arranged with the center conductors 41a, 41b, 41c interposed therebetween. .

Further, magnets for magnetizing the ferrites 42a and 42b are arranged outside the ground conductors 43a and 43b, but they are omitted in the drawing.

Further, the capacitors 44a, 44b, 44c connected to the center conductors 41a, 41b, 41c are for performing tuning with the lumped-constant inductance due to the ferrite at the operating frequency thereof. , 41b, 41c are connected in parallel or in series. In the example of FIG. 4, they are connected in parallel.

The other ends of the center conductors 41a, 41b, 41c are grounded, for example.

In the lumped-constant circulator having the above-mentioned configuration, there are, for example, the following three methods for insulating the three sets of central conductors from each other. 1) As shown in FIG. 5 (a), copper plating is applied to both sides of one thin dielectric substrate 50, and the copper plating on the surface is selectively etched to form branching center conductors 51a, 51b, 51c. To form. Then, as shown in FIG. 5B which is a cross section taken along the line AB of FIG. 5A, through holes 52 are formed at the intersections of the central conductors 51a, 51b, 51c, and the back surface of the substrate 50 is formed. A method of connecting one's own branch so that it does not contact the branch of another center conductor.

2) As shown in the cross-sectional view of FIG. 6, the center conductors 61a, 61b, 61c are woven into hairpins, and an insulating sheet 62a such as a Teflon (registered trademark) sheet is interposed between the center conductors.
A method of sandwiching 62b and 62c. In the figure, 63a and 63b are ferrites, and 64a and 64b are ground conductors.

3) As shown in FIG. 7, insulating cross sections 73a, 73b such as bridges are formed on the surface of the ferrite 72b by, for example, an etching technique so that the center conductors 71a, 71b, 71c do not contact each other at the cross sections. Method. In the figure, 74b is a ground conductor.

In addition to the above method, as shown in FIG. 8, three sets of central conductors 81a, 81b, 81c, which are branched into a plurality, are arranged in the vertical direction so as to intersect with each other at 120 degrees, There is also a method of sandwiching the insulating sheets 82a and 82b between the conductors 81a, 81b and 81c.

Reference numerals 83a and 83b are ferrites, and 84a and 84b are ground conductors.

The structure shown in FIG. 8 is often used in a lumped-constant circulator, which operates at high power.

By the way, the lumped-constant circulators shown in FIGS. 5 to 7 must have symmetrical structures so that the values of the stray capacitances seen from the terminals are symmetrical. Therefore, the structure becomes complicated accordingly.

However, there is an advantage that the tuning capacitors 4a, 4b, and 4c connected to the three sets of center conductors can have the same capacitance value, and are used for a lumped constant type circulator that operates at relatively low power.

The lumped-constant circulator shown in FIG. 8 is simple in configuration and assembly, but the stray capacitance seen from each terminal is not symmetrical. For this reason, the capacitance value of the tuning capacitor connected to each terminal varies from terminal to terminal.

It should be noted that the capacitance value of each tuning capacitor can be maintained at a constant value if the reproducibility of assembly is perfect.

[0021]

[Problems to be solved by the device]

 By the way, the relative permittivity of ferrite is relatively large (the relative permittivity is about 11 to 16).

Therefore, when a lumped-constant circulator is constructed, a large difference occurs in the stray capacitance generated at each terminal, depending on whether or not there is a space between the ferrite and the central conductor.

When there is a difference in the stray capacitance between the terminals as described above, the capacitance value of the tuning capacitor connected to each terminal must be adjusted for each circulator.

Further, the space between the center conductor and the insulation sheet that insulates the center conductors also causes a large difference in the stray capacitance of each terminal, and the capacitance of the tuning capacitor connected to each terminal of the circulator. It becomes a factor that causes variations in the values.

The above problem also applies when there is a space between the ferrite and the ground conductor. By the way, adjusting the capacitance value of the tuning capacitor consumes a lot of time and makes it difficult to supply an inexpensive circulator.

In addition, when operating at high power, if there is a space between the ferrite and the center conductor or between the ferrite and the ground conductor, the heat loss generated in the ferrite cannot be sufficiently released.

Therefore, the temperature rises and the characteristics deteriorate, and the center conductor, the insulating sheet and the ferrite are burned out.

As described above, in the conventional lumped constant type circulator, it is easy to form a non-uniform space between the ferrite and the center conductor, between the ferrite and the ground conductor, or between the insulating sheet and the center conductor. , Stray capacitance of each terminal varies.

Therefore, the value of the tuning capacitor connected to each terminal must be adjusted for each circulator.

Further, when operating at high power, it is difficult for the loss heat generated in the ferrite to be transmitted to the case or the radiator through the ground conductor or the center conductor, and the operating power of the circulator is limited. In particular, when the circulator is used as an isolator, the sudden increase in the reflected power may lead to the destruction of ferrite and the insulator.

The present invention eliminates the space generated between the ferrite and the center conductor, between the ferrite and the ground conductor, and between the insulator and the center conductor, and adjusts the value of the tuning capacitor connected to each terminal. It is an object of the present invention to provide a lumped-constant type circulator that does not require the work to be done, releases heat generated in ferrite, and facilitates assembly.

[0032]

[Means for Solving the Problems]

 The present invention has first to third reticulated center conductors each having a plurality of branches and arranged so as to intersect each other, and a first to third reticulated center conductors inserted between the reticulated center conductors in order from the top. The first and second insulators, the first and second ferrites sandwiching the reticulated center conductor and the insulator from above and below, the grounding conductors arranged in close contact with each outside of the ferrites, and the magnetic field on the ferrites. In the central constant circulator composed of a magnet that imparts a magnet, the reticulated center conductor is made of copper, the insulator is made of ceramic, and the reticulated center conductor, the insulator, and the ferrite are The first ferrite, the first reticulated center conductor, the first insulator, the second reticulated center conductor, the second insulator, the third reticulated center conductor, and the second ferrite are stacked in this order, and these are directly Contact The contact is formed.

The ground conductor is made of copper, and the ground conductors are connected to each other by direct bonding.

[0034]

[Action]

 According to the above configuration, the reticulated center conductor and the ground conductor are made of copper, and the center conductor and the ground conductor are formed by adhering to the ferrite by direct bonding between the copper and the ferrite.

The insulator that insulates the center conductors is made of ceramics, and the center conductor and the insulator are also adhered and formed by direct bonding.

As a method for forming the center conductor and the ground conductor in close contact with the ferrite, there are methods such as metal vapor deposition and thick film sintering.

Direct bonding copper technology (hereinafter DBC technology) for directly bonding copper and a ceramic substrate under conditions of moderate temperature (about 1100 ° C.) and moderate amount of oxygen (several ppm) in the atmosphere. Is also adopted.

The ferrite forming the lumped-constant circulator is an oxide ceramic, and can be directly bonded to copper.

In the present invention, the material of the ground conductor and the center conductor is copper, the insulator is ceramic, and the ground conductor, the center conductor, the ferrite, and the insulator are joined by the DBC technique.

Therefore, it is possible to eliminate a space between the ferrite and the central conductor or the ground conductor, or between the central conductor and the insulator.

Therefore, there is no variation in size of the stray capacitance seen from each terminal.

Further, the thermal resistance between the ferrite and the ground conductor, that is, from the ferrite to the case and the heat radiating portion also becomes small.

Since the ground conductors sandwiching the central conductor and the ferrite from both sides are also connected by the DBC technique, the lumped constant type circulator can be easily assembled.

[0044]

【Example】

 An embodiment of the present invention will be described below with reference to the schematic sectional view of FIG. Reference numerals 11a, 11b, and 11c are central conductors made of copper, and the central conductors 11a, 11b, and 11c each have a plurality of branches, and are arranged in a vertical direction so as to intersect each other.

Further, ferrites 12a and 12b are arranged outside the center conductors 11a and 11c. The ground conductors 13a and 13b are arranged outside the ferrites 12a and 12b.

Insulating sheets 14a and 14b are sandwiched between the center conductor 11a and the center conductor 11b and between the center conductor 11b and the center conductor 11c.

The ground conductors 13a and 13b are made of copper, the insulating sheets 14a and 14b are made of ceramic, and the central conductors 11a, 11b and 11c and the insulating sheets 14a and 14b, the ferrites 12a and 12b, The ground conductors 13a and 13b are fixed to each other by DBC technology.

The exposed portions of the ground conductors 13a, 13b and the center conductors 11a, 11b, 11c can be plated, and silver with good conductivity can also be plated.

Here, a procedure for joining the ground conductors 13a, 13b, the center conductors 11a, 11b, 11c, the insulating sheets 14a, 14b, and the like to each other using the DBC technique will be described.

First, the ground conductor 13a is closely attached to one surface of the ferrite 12a and temporarily fixed. Further, the central conductor 11a is closely attached to the other surface of the ferrite 12a and temporarily fixed.

Then, the insulating sheet 14a is overlaid on the central conductor 11a, and further, the central conductor 11b, the insulating sheet 14b, the central conductor 11c, the ferrite 12b, and the ground conductor 13b are sequentially overlaid and temporarily fixed.

The center conductors 11a, 11b, 11c are arranged so as to intersect each other at about 120 degrees about the centers of the ferrites 12a, 12b.

Then, the ground conductors 13a, 13b and the central conductors 11a, 11b, 11c, etc. are left temporarily in an electric furnace set to an atmosphere containing a proper temperature and a proper amount of oxygen while being temporarily fixed.

In the electric furnace, only copper on the surfaces of the ground conductors 13a, 13b and the center conductors 11a, 11b, 11c is melted and covalently bonded with oxygen contained in the ferrites 12a, 12b and the insulating sheets 14a, 14b. The ferrites 12a and 12b, the center conductors 11a, 11b and 11c, the insulating sheets 14a and 14b, and the ground conductors 13a and 13b are firmly joined to each other without forming a space therebetween.

Further, the ground conductor 13a is provided with protrusions 15a, 15b (not shown) and 15c extending outward from the peripheral portions of the ferrites 12a and 12b, and the protrusions 15a, 15b and 15c are It is bent and connected to the other ground conductor 13b with solders 16a, 16b (not shown), 16c.

Therefore, the ground conductor 13a and the ground conductor 13b have the same potential.

When the DBC technique is adopted as a method for forming the center conductors 11a, 11b, 11c and the ground conductors 13a, 13b in close contact with ferrite as described above, it is possible to obtain them by a method such as metal vapor deposition or thick film sintering. The following structure is possible.

In the case of metal vapor deposition or thick film sintering, the portion where the ground conductor and the center conductor adhere to ferrite is limited to the ferrite surface region.

Therefore, terminals for connecting the external matching circuit cannot be formed simultaneously and integrally.

However, by using the DBC technique, it is possible to form a central conductor or a ground conductor having terminals or protrusions extending outside the area of the ferrite surface in close contact with the ferrite surface, as in the above-described embodiment.

As the insulating sheets 14a and 14b, it is suitable to use, for example, alumina, which has a small loss at high frequencies, has a large withstand voltage so as to withstand high power operation, and is easily processed thin.

A magnet (not shown) that gives a magnetic field to the ferrites 12a and 12b is arranged outside both of the ground conductors 13a and 13b or outside either one of them.

The insulating sheets 14a and 14b are usually formed in a circular shape having the same area as the ferrite. However, the insulating sheets 14a and 14b may have any shape as long as they can insulate the intersecting portions of the central conductor 11b and the upper and lower central conductors 11a and 11c. For example, a rectangular shape along the width of the central conductor 11b as shown in FIG. It may have a shape.

In FIG. 2, the same parts as those in FIG. 1 are designated by the same reference numerals, and the duplicate description will be omitted.

In the above embodiment, the ground conductors 13a and 13b are connected to each other by soldering. However, since the DBC technology can also connect copper to each other, as shown in FIG. 3, for example, the protrusions 17a, 17b (not shown) and 17c are provided on the side of the ground conductor 13b, and the protrusions 15a on the side of the ground conductor 13a are provided. , 15b and 15c can be joined by the DBC technique. This structure eliminates the need for soldering and shortens the assembly time.

In FIG. 3, the same parts as those in FIG. 1 are designated by the same reference numerals, and overlapping description will be omitted.

[0067]

[Effect of device]

 In the present invention, the ferrite, the center conductor, the insulating sheet, and the ground conductor are directly joined by the DBC technique.

Therefore, it is possible to eliminate the generation of a space between the center conductor and the ferrite or the insulating sheet, and further between the ground conductor and the ferrite.

Therefore, there is no variation in the size of the stray capacitance seen from each terminal, there is no variation in the value of the tuning capacitor connected to each terminal, and the circulator adjustment time can be shortened.

Further, the thermal resistance between the ferrite and the ground conductor, that is, up to the case and the heat radiating portion also becomes small, and the operating power of the circulator can be increased.

Further, by directly joining the ground conductors together, the assembly time can be shortened.

[Brief description of drawings]

FIG. 1 is a sectional view illustrating an embodiment of the present invention.

FIG. 2 is a sectional view illustrating another embodiment of the present invention.

FIG. 3 is a cross-sectional view illustrating another embodiment of the present invention.

FIG. 4 is a diagram illustrating a conventional example.

FIG. 5 is a diagram illustrating a conventional example.

FIG. 6 is a diagram illustrating a conventional example.

FIG. 7 is a diagram illustrating a conventional example.

FIG. 8 is a diagram illustrating a conventional example.

[Explanation of symbols]

 11a, 11b, 11c ... Central conductor 12a, 12b ... Ferrite 13a, 13b ... Ground conductor 14a, 14b ... Insulation sheet 15a, 15b, 15c ... Protrusion 16a, 16b ... Solder

Claims (2)

[Scope of utility model registration request] 1. A first to third reticulated center conductors, each of which has a plurality of branches, and are arranged so as to intersect with each other, and a top inserted in order between the reticulated center conductors. The first and second insulators, the first and second ferrites sandwiching the reticulated center conductor and the insulator from above and below, the ground conductors arranged in close contact with each outside of the ferrites, and the ferrites. In a lumped constant type circulator including a magnet for applying a magnetic field, the mesh center conductor is made of copper, the insulator is made of ceramic, and the mesh center conductor, the insulator, and the ferrite are the first Ferrite, first reticulated center conductor,
The first insulator, the second reticulated center conductor, the second insulator, the third reticulated center conductor, and the second ferrite are stacked in this order,
A lumped constant type circulator characterized in that these are closely adhered and formed by direct bonding. 2. The first to third reticulated center conductors, each of which has a plurality of branches, are arranged so as to intersect with each other, and the reticulated center conductors are inserted between the reticulated center conductors. The first and second insulators, the first and second ferrites sandwiching the reticulated center conductor and the insulator from above and below, the ground conductors arranged in close contact with each outside of the ferrites, and the ferrites. A lumped constant circulator comprising a magnet for applying a magnetic field, wherein the ground conductor is made of copper, and the ground conductors are directly connected to each other.