JPS6341245B2 - - Google Patents

Description

[Detailed Description of the Invention] (1) Technical Field of the Invention The present invention provides a distributed constant type MIC that operates in a low magnetic field.
Regarding circulators.

(2) Background of the technology As is well known, a circulator is a circuit in which the direction of input and output is determined cyclically between many terminals, and there are various types such as waveguide circulators, coaxial circulators, MIC circulators, etc. It is incorporated into the microwave circuit. Among these formats, the present invention is particularly suitable for MIC (Microwave)
Integrated Circuit) refers to the circulator. This MIC circulator is compatible with the use of ICs in microwave circuits, and is excellent in terms of mass production, reproducibility, and low cost.

This MIC circulator basically consists of a ferrite substrate and a DC magnetic field generator for magnetizing the ferrite substrate, and a pattern made of a thin film or thick film conductor is applied to the surface of the ferrite substrate. When trying to improve the characteristics of a MIC circulator having such a configuration, one of the important factors is the problem of uniform magnetization by the DC magnetic field generator of the ferrite substrate. In other words, it is required to form a magnetic field of the same magnitude everywhere on the ferrite substrate.

(3) Prior art and problems Figure 1A is a plan view showing a general MIC circulator. In this figure, numeral 11 is a ferrite substrate, and a conductor pattern 12 is formed on the surface thereof. However, the case where three input/output terminals are provided will be exemplified.

FIG. 1B is a side view taken along arrow 1B in FIG. 1A. In this figure, 13 is a DC magnetic field generator, which forms a DC magnetic field within the ferrite substrate 11. In other words, the ferrite substrate is magnetized. It is desirable that this magnetization be uniform with an optimum magnetic flux density.
However, in reality, the DC magnetic field generator 13 (specifically and practically, it is a magnet;
Such uniform magnetization is difficult due to the inherent characteristics (also called magnetization). FIG. 2 is a graph showing the general magnetic field distribution of a magnet. In this graph, the horizontal axis indicates the position L corresponding to the magnet, and the vertical axis indicates the magnetic flux density B at each position. The solid curve in this graph is the general characteristic of magnets, which are curved as a whole and are not flat characteristics. Ideal flat characteristics are shown by the dashed line in this graph, and the present invention aims at proposing a DC magnetic field generator 13 having such flat characteristics. If the DC magnetic field generator 13 is a DC magnetic field with flat characteristics, the ferrite substrate 11 will naturally be magnetized uniformly.

Conventionally, it has been practical to interpose a magnetic plate in order to generate a DC magnetic field with flat characteristics as described above. Figure 3A is a side view showing the first example of a conventional MIC circulator, and Figure 3b is a side view of a conventional MIC circulator.
It is a side view which shows the 2nd example of a MIC circulator. In FIG. 3A, 31 is the magnetic plate mentioned above, specifically an iron plate. FIG. 3B shows an example in which the second magnetic plate 32 is also arranged on the upper surface side of the ferrite substrate 11. In this way, the magnetic plates 31, 32
By interposing the DC magnetic field, the formation of the DC magnetic field becomes somewhat dispersed, and the curved surface does not appear as conspicuously curved as the solid line curve in FIG. However, according to actual measurements, the characteristics are not as uniform as the one-dot chain line in the figure. Thus, the uniform magnetization within the ferrite substrate 11 in the MIC circulator is not perfect, and there is a problem in that, for example, it is not possible to sufficiently widen the bandwidth of the microwave circuit and reduce the loss.

(4) Purpose of the Invention In view of the above problems, the present invention aims to propose a distributed constant type MIC circulator that operates in a low magnetic field and enables uniform magnetization within a ferrite substrate.

(5) Structure of the invention In order to achieve the above object, the present invention is characterized in that at least one of a pair of DC magnetic field generating magnetic pole parts in a DC magnetic field generator has a substantially conical shape. .

(6) Embodiments of the Invention FIG. 4 is a side view showing a first embodiment of a DC magnetic field generator used in a MIC circulator according to the present invention. In this figure, the DC magnetic field generator 41
In the figure, the upper and lower surfaces are a pair of DC magnetic field generating magnetic pole parts, and at least one of them (the upper side in the figure)
is approximately conical in shape. In this way, the magnitude of the generated magnetic field will be approximately the same no matter where the generator 41 is located. This is illustrated by the dotted arrow in the figure. The principle of the present invention can be considered as follows. Generally, a magnetic dipole is formed between a pair of magnetic pole parts, and the greater the thickness of the dipole, the greater the magnitude of the magnetic field. Increasing the thickness of the central portion, as shown in FIG. 4, therefore leads to increasing the magnitude of the magnetic field. Therefore, with the magnetic field increased in this way, it is possible to reinforce the central portion where the magnetic field is weak, as shown in FIG.

FIG. 5 is a side view showing a second embodiment in which substantially conical magnetic pole portions are formed on the upper and lower surfaces of the magnet. Based on the above-mentioned principle, it is clear that the same effect can be produced even if it is provided on both of the pair of DC magnetic field generating magnetic pole parts.

Next, an example of its configuration will be described using the DC magnetic field generator 41 shown in FIG. 4 as an example (the same applies to the case of FIG. 5). FIG. 6 is a sectional view showing an example of the structure of the DC magnetic field generator shown in FIG. 4. As shown in the figure, according to this configuration example, the entire magnet 61, including the substantially conical portion, is constructed. Normally, magnets are sintered bodies, and once a mold is made, it is easy to mass-produce magnets in this shape.

FIG. 7 is a cross-sectional view showing another configuration example of the DC magnetic field generator shown in FIG.
is fixed, and one magnetic pole part (the other is fixed to the DC magnetic field generating magnetic pole part of the magnet 71) has a substantially conical shape.

Figures 8A, 8B, 8C and 8D are side views schematically showing the positioning of the DC magnetic field generator according to the present invention in the MIC circulator.
However, an example using the one shown in FIG. 4 will be shown. As shown in these figures, the DC magnetic field generator 41 may be placed on the upper surface or the lower surface of the ferrite substrate 11. Further, the DC magnetic field generator 41 is fixed to the ferrite substrate 11 with a suitable adhesive (not shown).

(7) Effects of the invention As explained in detail above, according to the present invention,
Uniform magnetization of the ferrite substrate becomes possible, creating a MIC circulator with improved characteristics in terms of wider bandwidth and lower loss.

[Brief explanation of the drawing]

Fig. 1A is a plan view showing a general MIC circulator, Fig. 1B is a side view taken from arrow 1B in Fig. 1A, Fig. 2 is a graph showing a general magnetic field distribution of a magnet, and Fig. 3A is a conventional MIC circulator. A side view showing the first example of the MIC circulator, Figure 3B is a conventional
FIG. 4 is a side view showing a second example of the MIC circulator, FIG. 4 is a side view showing the first example of the DC magnetic field generator used in the MIC circulator according to the present invention, and FIG. A side view showing the second embodiment formed on the top and bottom surfaces, FIG. 6 is a sectional view showing an example of the structure of the DC magnetic field generator shown in FIG. 4, and FIG. Cross-sectional diagrams showing other configuration examples, Nos. 8A, 8B, 8C
and 8D diagram of the DC magnetic field generator according to the present invention.
FIG. 2 is a side view schematically showing the positioning in the MIC circulator. 11... Ferrite substrate, 12... Conductor pattern, 41, 42... DC magnetic field generator according to the present invention.

Claims (1)

[Claims] 1. A distributed constant type MIC that operates in a low magnetic field and includes a ferrite substrate with a predetermined conductor pattern on its surface, and a DC magnetic field generator for magnetizing the inside of the ferrite substrate. A MIC circulator, characterized in that at least one of a pair of DC magnetic field generating magnetic pole portions of the DC magnetic field generator has a substantially conical shape, and magnetization within the ferrite substrate is made uniform. 2. The MIC circulator according to claim 1, wherein the DC magnetic field generator comprises a magnet, and the DC magnetic field generating magnetic pole portion of the magnet has a substantially conical shape. 3. The DC magnetic field generator comprises a magnet and a pole piece fixed to a DC magnetic field generating magnetic pole part of the magnet, and one magnetic pole part of the pole piece has a substantially conical shape.
MIC circulator.