JPS6030121B2 - Lumped circulators and isolators - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to improvements in compact, high-performance lumped constant circulators and isolators used in the VHF band, UHF band, and microwave band.

Lumped constant circulators and isolators, which are the most important components of microwave equipment, are used in the microwave field for purposes such as protecting transistors during high-power operation, matching between stages, and eliminating unnecessary reflections. On the other hand, with the recent dramatic downsizing of other microwave elements, the space occupied by circulators and isolators in the entire microwave apparatus has become quite noticeable. for example,
In some types of devices, it is not uncommon for these bond occupancy rates to exceed 50%. Furthermore, from the perspective of the overall cost of the microwave device, the price of the circulator and isolator accounts for a considerable amount. For this reason, the demands for smaller size, lower cost, and higher performance for circulation isolators are becoming stronger day by day.

The present invention relates to a structural improvement of a lumped constant type circulator/isolator in order to meet the industrial demand for miniaturization in particular. In general, the structure of a conventional lumped constant type circulator is such that two permanent magnets 3a and 3b are attached above and below in a case 1 to play the role of magnetic circuit and electrical shielding, as shown in Fig. 4. In the central space, two ferrite cores 6a, 6b and a center conductor 7 are surrounded by a shield plate 5 and placed on a grounding stand.

Further, the upper magnet 3b is moved vertically by the rotating screw 2, and the magnetic field applied to the ferrite core is finely adjusted. FIG. 3 shows the inside of the shield plate 5 having a secondary structure and shows the relationship between a set of three mesh-like central conductors and two ferrite cores 6a and 6b on a disk. In the diagram,
To make the arrangement easier to understand, ferrite cores 6a, 6
The interval b is much wider than it actually is. Three parallel conductors 7a, 7b, and 7c intersect with each other at 1200 near the center to form a set of mesh-like central conductors.

The parallel conductors 7a, 7b, and 7c are each insulated at the center, but one end of each is externally grounded. Actually, it is connected to the shield plate 5. The circuit having the conventional structure thus constructed is also represented by an equivalent circuit as shown in FIG. In this), Lp mainly equivalently represents the inductance due to 7a, 7b, and 7c shown in FIG. Cp is the sum of the capacitance of an externally added capacitor and other stray capacitances. A,
B and C are input terminals for connection to an external circuit, and are connected to the other ungrounded ends of the center conductors 7a, 7b, and 7c. Now, when using the conventional structures shown in FIGS. 1, 3, and 4 and aiming for miniaturization, which is a strong demand in the industry, the following design problems are immediately faced.

[1} The optimum diameter DGo of the ferrite core is inversely proportional to the operating frequency f.

In the case of low frequencies such as the VHF band, the circulator
The size of the isolator becomes large, which is a serious problem in terms of device design. (2) If the diameter DG of the ferrite core is made small ignoring the above conditions, the impedance becomes extremely small and matching with an external circuit becomes difficult. Although it is possible to increase the impedance inside the circulator by changing the magnetic field adjustment screw, this may have an adverse effect on insertion loss and bandwidth, and may not be usable in some cases. FIG. 2 shows a means for performing impedance conversion by connecting a series inductance Ls and a parallel capacitor Cp' in order to compensate for the decrease in impedance when the size of the ferrite core is reduced.

However, even in this case, the added inductance Ls
, insertion loss also increases due to the presence of capacitor Cp',
The disadvantage is that it is impossible to avoid the effect of narrowing the castle grounds. SUMMARY OF THE INVENTION It is an object of the present invention to solve the above-mentioned drawbacks of the prior art and to provide a compact and high-performance lumped constant type circular/isolator.

In order to achieve the above object, the present invention uses n (n≧3) ferrimagnetic materials and stacks them in a lumped constant type circulator and isolator that are constructed by applying a DC magnetic field to ferrimagnetic materials. It occurs when combining (n-
1) A set of 3 mesh central conductors is placed between each layer.
A total of (n-1) sets are arranged, and the above (n-1
) It is characterized by having silk central conductors electrically connected in series.

Hereinafter, the present invention will be explained in detail with reference to Examples.

FIG. 6 is a schematic configuration diagram showing an embodiment of the present invention.
Three ferrite cores 6a, 6b, 6c form the shield plate 5
is stored inside.

Two sets of three mesh central conductors are inserted between two layers composed of three ferrite cores 6a, 6b, and 6c, and these are electrically connected in series.

These situations are shown in more detail in FIG. In the figure, the spacing between ferrite cores is drawn much wider than it actually is in order to make it easier to understand the arrangement of the center conductors. In this), the two sets of mesh center conductors are 12a, 12b, 1
2c and 12'a, 12'b, 12'c. A set of three center conductors 12'a, 12'
One end of each of b and 12'c is grounded. These are actually connected to the shield plate 5 or the ground stand 4. The other end of the center conductors 12'a, 12'b, 12'c is connected to another set of center conductors 12a, 12b, 12'.
c is connected to one end of each of the ferrite cores 6 on the outside of the ferrite core 6. The other ends of the center conductors 12a, 12b, and 12c are used for connecting an external circuit. In this way,
The inductance formed by the center conductors 12'a, 12'b, and 12'c and the inductance formed by the central conductors 12a, 12b, and 12c are connected in series in terms of an electric circuit.
The inductance is significantly larger than the conventional product with one set of center conductors. In other words, in terms of the electrical circuit, this is equivalent to using a ferrite core that is approximately twice the diameter, and the internal impedance can be increased to a large extent without increasing the overall dimensions of the lumped constant type circulator. It has significant advantages that it does not have. FIG. 9 is a 20 blood zone and 3
We will show the electrical performance of a small lumped constant type circulator created by Kaku Kaku.

This is the case using the structure of the prior art at an elevation angle of 3 degrees. The ferrite cores 6 used were both on the diameter 12 side. As is clear from this figure, the electrical characteristics of the device using this example are significantly improved compared to the conventional structure, both during the isolation mountain ss coverage and insertion loss. I understand. Considering that a five ratio cape angle is definitely required to obtain the same characteristics as the opening in Figure 9 using the prior art, it is clear that the present invention has a remarkable effect in terms of miniaturization. be.
FIG. 7 is a schematic structural diagram showing another embodiment of the present invention.

This structure shows a lumped constant type circulator using a single magnet type already provided by the present invention in order to reduce the thickness of the circulator, unlike the dual magnet type shown in FIG. 9)
10 is a permanent magnet, 10 is a ground plate, and 19 is an upper soft magnetic body. Even in this structure, it is possible to use the arrangement of the three ferrite cores 6 and the center conductor 12 shown in FIG. Using this, 200
A MHz band lumped constant type circulator was created and the same results as those shown in Figure 9 were obtained. In this figure, the ground stand 10 and the shield plate 5 are depicted as separate pieces, but in reality, they are often made as one piece. Also,
Although a case is not shown in FIG. 7, it is possible to cover it with a magnetic shield case, an electrical shield case, or a simple plastic case, if necessary.
FIG. 8 is a schematic structural diagram showing another embodiment of the present invention. In this case, 6a and 6 are used as ferrite cores.
Three sets of mesh-shaped central conductors 13 are inserted between the layers of the ferrite core. The three sets of mesh-like center conductors are electrically connected in series at the outer periphery of the ferrite core, as in FIG. 5.

By using this structure, we were able to realize a small lumped constant type circulator with a small size of 3 degrees square, but with insertion loss comparable to that of Figure 9 even in the 150M household bandwidth. As described above in detail using the embodiments, the feature of the present invention is that three or more ferrite cores are used, a center conductor is arranged between the layers, and they are electrically connected in series. The advantages of the present invention are listed below.

○} By increasing the number of ferrite cores, it is theoretically possible to reduce the dimensions of the circulator/isolator to a considerable extent.

'2} When compared with a conventional structure with the same dimensions, insertion loss and specific bandwidth were significantly improved. The above-mentioned advantages meet the industrial demands for miniaturization and high performance that are originally required for these products, and the effects of the present invention are particularly effective from the viewpoint of resource saving and energy saving, which have been emphasized recently. We are confident that we will be able to fully meet the expectations of this type of industry.

[Brief explanation of the drawing]

Figures 1 and 2 are equivalent circuits of conventional lumped constant type circulators and isolators; Figures 3 and 4 are schematic assembly structure diagrams of conventional circuits; Figures 5, 6, 7, and FIG. 8 is a schematic structural diagram showing an embodiment of the present invention, and FIG. 9 is a characteristic comparison diagram between a conventional product and the present invention. 1: Case, 2: Adjustment screw, 3a, 3b, 9: Permanent magnet, 4, 10: Earth, 5: Shield plate, 6: Ferrite core, 12: Center conductor, 8, 19: Soft magnetic material, 20: Heat sink . Na, 2, 3, 4, O, 5, 6, 7, 8, 8

Claims (1)

[Claims] 1 In lumped constant type circulators and isolators configured by applying a DC magnetic field to a Ferry magnetic material,
Using n (n≧3) Ferrie magnetic materials, a total of (n-1) sets of three mesh-like center conductors are arranged between each of the (n-1) layers created when these are superimposed. A lumped constant type circulator and isolator, characterized in that the (n-1) sets of center conductors are connected in series.