JPH0448002Y2 - - Google Patents

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a magnetic device that applies a magnetic field to a device such as a ferromagnetic thin film filter having a magnetic resonance element, and is capable of adjusting the magnetic field.

[Summary of the idea]

The present invention relates to a magnetic device, in which a device is arranged in the gap of a magnetic yoke having a pair of pole pieces, a coil is wound around one pole piece, and an adjustment is wound around the other pole piece. By providing a screw and rotating the adjustment screw to adjust the magnetic field applied to the device, the accuracy of the adjustment of the magnetic field by the adjustment screw is improved, making the adjustment easier, and the adjustment screw and This makes it possible to easily form the screw hole.

[Conventional technology]

In a conventional filter using a ferromagnetic thin film such as YIG (for example, Japanese Patent Laid-Open No. 103403/1983), it is necessary to apply a bias magnetic field to the ferromagnetic thin film using a permanent magnet or an electromagnet. Magnetic devices for this purpose are described in Japanese Patent Application No. 59-44244, Japanese Patent Application No. 59-180941, etc.

First, a conventional example of a magnetic device will be described with reference to FIG. 3 indicates a magnetic yoke, which consists of an upper magnetic yoke 1 and a lower magnetic yoke 2. These upper and lower magnetic yokes 1, 2
are joined at their respective flanges 1a and 1b to form a magnetic yoke 3.

Pole pieces 1A and 2A are integrally provided inside the upper and lower magnetic yokes 1 and 2, respectively. These pole pieces 1A, 2A are arranged so that a gap G is formed between their opposing ends when the upper and lower magnetic yokes 1, 2 are joined. Then, within this gap G, a device 7 such as the above-mentioned filter is placed.

Pole pieces 1A and 2A each have coil 4.
A and 4B are wound. These coils 4A, 4B
are connected in series or in parallel, and a direct current (the current can be varied) is passed through them. In this case, the opposing ends of the pole pieces 1A and 2A are magnetized with different polarities.

For example, pole piece 1A of upper magnetic yoke 1
For example, two adjustment screws 5 and 6 are provided. That is, two screw holes are drilled in the pole piece 1A at a predetermined interval so that their axes are parallel to each other, and adjusting screws (male threads) 5 and 6 are screwed into these screw holes, respectively. do.

The positions of the adjusting screws 5 and 6 are set so that the free ends of the adjusting screws 5 and 6 face the two ferromagnetic thin films of the filter as the device 7, respectively.

In such a magnetic device, by rotating the adjustment screws 5 and 6 separately, the magnetic field applied to each ferromagnetic thin film of the filter is adjusted independently. The magnetic fields are made equal to equalize their resonant frequencies. That is, by setting the gap length between the opposing ends of the pole pieces 1A and 2A, the magnetic resistance of the gap G is set to a certain value, and by rotating the adjusting screws 5 and 6, The magnetic resistance will be finely adjusted.

[Problem that the invention attempts to solve]

By the way, such a conventional magnetic device has coils 4A and 4A on both pole pieces 1A and 2A of the magnetic yoke 3, respectively.
4B is wound, and both lengths are as long as 15 to 20 mm, so the adjustment screws 5 and 6 provided on one of the pole pieces 1A have approximately the same length.

For this reason, in such conventional magnetic devices, the accuracy of adjusting the magnetic field by the adjusting screws 5 and 6 is low, and the time required for adjustment is long, making adjustment troublesome.
Another drawback was that it was difficult to form the adjusting screws 5, 6 and their screw holes.

In view of these points, the present invention proposes a magnetic device that can improve the accuracy of magnetic field adjustment using an adjustment screw, facilitate the adjustment, and facilitate the formation of the adjustment screw and its screw hole. That is.

[Means for solving problems]

The magnetic device according to the present invention includes a magnetic yoke 3 having a pair of pole pieces 1A and 2A facing each other and having different lengths, and a pair of pole pieces 1A and 2A.
A device 7 using a ferromagnetic material arranged in a gap G between the two, a coil 4 wound around the longer pole piece 2A of the pair of pole pieces 1A and 2A, and a pair of pole pieces 1A. , 2A, and has adjustment screws 5 and 6 screwed into the screw holes, and the adjustment screws 5 and 6 are rotated. The magnetic field applied to the device 7 using a ferromagnetic material can be adjusted by moving the magnet.

[Effect]

According to the present invention, by rotating the adjustment screws 5 and 6, the magnetic field applied to the device 7 can be adjusted.

〔Example〕

Hereinafter, one embodiment of the present invention will be described in detail with reference to FIG. 3 indicates a magnetic yoke, which consists of an upper magnetic yoke 1 and a lower magnetic yoke 2. These upper and lower magnetic yokes 1,
2 are joined at their respective flanges 1a and 1b to form a magnetic yoke 3.

Pole pieces 1A and 2A are integrally provided inside the upper and lower magnetic yokes 1 and 2, respectively. These pole pieces 1A, 2A are arranged so that a gap G is formed between their opposing ends when the upper and lower magnetic yokes 1, 2 are joined. Then, within this gap G, a device 7 such as the above-mentioned filter is arranged.

The pole pieces 1A, 2A are set so that one of them, 1A, is short and the other, 2A, is long.
The coil 4 is wound only around the pole piece 2A.
A direct current (the current can be varied) is passed through this coil 4. In this case, pole piece 1A,
The opposite ends of the 2A are magnetized with different polarities.

And pole piece 1A of upper magnetic yoke 1
For example, two adjustment screws 5 and 6 are provided. That is, two penetrating screw holes are drilled in the pole piece 1A at a predetermined distance so that their axes are parallel to each other, and adjusting screws (male screws) 5 and 6 are inserted into these screw holes, respectively. Screw in.

The positions of the adjusting screws 5, 6 are set such that the free ends of the adjusting screws 5, 6 specifically face the two ferromagnetic thin films of the filter as the device 7.

In such a magnetic device, the magnetic fields applied to each ferromagnetic thin film of the filter are adjusted independently by specifically rotating the adjustment screws 5 and 6, and in this case, the magnetic fields are made equal, and the resonance is adjusted. Make the frequencies equal. That is, by setting the gap length between the opposing ends of the pole pieces 1A and 2A, the magnetic resistance of the magnetic yoke 3 is set to a certain value, and by rotating the adjusting screws 5 and 6, The magnetic resistance will be finely adjusted.

According to the magnetic device of this embodiment, of the pair of pole pieces 1A and 2A of the magnetic yoke 3, the coil 4 is wound around only one 2A, and the coil 4 is not wound around the other pole piece 1A. can be significantly shortened. Therefore, the length of the adjustment screws 5 and 6 provided on this pole piece 1A can be considerably shortened.

Next, an example of the device 7 will be described with reference to FIGS. 3 and 4. This is a two-stage filter that uses a YIG thin film as a ferromagnetic thin film. 11
1 is a quartz substrate serving as a dielectric substrate, and a ground conductive layer 12 is formed over the entire back surface of the quartz substrate. Input and output side microstrip lines (conductive layers) 13 and 14 are deposited near both sides of the surface of this quartz substrate 11 and extend in parallel to each other in first and second directions opposite to each other. , each of which is oppositely opened once. 13A,1
4A is each open end of the microstrip lines 13 and 14. Reference numeral 17 denotes a GGG (gadolium gallium garnet) plate, and a YIG thin film 15 in the form of a disk is formed using photolithography using a YIG thin film grown on the GGG (gadolium gallium garnet) plate by liquid phase epitaxial method.
16, and each YIG thin film 15, 16 is connected to the input and output side microstrip lines 13, 14.
The upper open ends 13A and 14A are placed in close contact with each other at a distance of a characteristic described later. this
On the other main surface of the GGG plate 17, a YIG thin film 15,
A connecting microstrip line 18 is formed so as to face the microstrip line 16 and intersect the input and output side microstrip lines 13 and 14, and both ends thereof are open. 18A and 18B are both open ends of the microstrip line 18. Then, the filter shown in FIGS. 3 and 4 is placed in the gap G of the magnetic device shown in FIG.
Due to its Ferrimagnetic resonance, a uniform bias DC magnetic field perpendicular to the membrane surface is applied to obtain a fixed or variable filter device.

Then, the length (physical length) f of the mutually opposing portions of the input and output microstrip lines 13 and 14 is set to an integral multiple of approximately 1/2 of the propagation wavelength λ of the signal in the passband, here λ/2. be selected. Furthermore, microstrip lines 13, 14 and 1
8 open ends 13A, 14A and 18A, 18
The lengths (physical lengths) a, b, c, and d from the center of each of the disk-shaped YIG thin films 15 and 16 in B are odd multiples of approximately 1/4 of the propagation wavelength λ of the signal in the passband, Here, λ/4 is selected.

Furthermore, the distance e between the input and output side microstrip lines 13 and 14 (disk-shaped YIG thin film 15,
16) is selected to be approximately 1/2 or less (preferably approximately λ/4 or less) of the propagation wavelength λ of the signal in the passband, here approximately λ/4.
In this case, it is desirable that the distance e be short unless direct bonding occurs between the YIG thin films 15 and 16.

Next, let's explain how this filter works. When a high frequency signal with a propagation wavelength λ is supplied to the input side microstrip line 13, the high frequency signal propagates to the open end 13A, but at the open end,
The voltage is maximum, the current is minimum (zero), and the magnetic field is minimum (zero). On the other hand, since the length from the open end 13A to the YIG thin film 15 is selected as described above, the YIG
Conversely, at the center position of the thin film 15, the voltage is minimum (zero),
Maximum current and maximum magnetic field. Therefore, at the center position of the YIG thin film 15, the high frequency coupling efficiency due to the magnetic field between the microstripline 13 and the YIG thin film 15 is maximized, and the input side microstripline 13 and the connecting microstripline 18 The degree of capacitive coupling due to the voltage between them is minimized, and isolation is achieved.

Furthermore, when a high frequency signal having a wavelength different from λ is supplied to the input side microstrip line 13, there is a signal between the microstrip line 13, the YIG thin film 15, and the connecting microstrip line 18. Since the magnetic coupling degree and the capacitive coupling degree are of the same value, no isolation is taken.

If a bias DC magnetic field perpendicular to the film surface is applied to the YIG thin film 15, Ferrimagnetic resonance will occur at a certain frequency, and when isolation is achieved at that frequency, this frequency will be set as the band center frequency. A bandpass filter is obtained. still,
Microstrip line 18 and YIG thin film 18
The same can be said about the relationship between the output side microstrip line 14 and the output side microstrip line 14.

Note that the device 7 of the magnetic device is not limited to such a ferromagnetic thin film filter, but other devices may also be used.

[Effect of idea]

According to the present invention described above, since the coil is not wound around the pole piece on which the adjusting screw is provided, the pole piece can be shortened, improving the accuracy of magnetic field adjustment by the adjusting screw, and making the adjustment easier. At the same time, it is possible to obtain a magnetic device that can facilitate the formation of the adjustment screw and its screw hole.

[Brief explanation of the drawing]

Fig. 1 is a sectional view showing one embodiment of the present invention;
The figure is a sectional view showing a conventional example, and FIGS. 3 and 4 are a plan view and a sectional view of a filter as a husbandry device. 1A and 2A are pole pieces, 3 is magnetic yoke,
4 is a coil, 5 and 6 are adjustment screws, and 7 is a device (filter).

Claims (1)

[Claims for Utility Model Registration] A magnetic yoke having a pair of pole pieces of different lengths facing each other; a device using a ferromagnetic material arranged in a gap between the pair of pole pieces; A coil wound around the longer pole piece of the pair of pole pieces, a screw hole drilled through the shorter pole piece of the pair of pole pieces, and a screw threaded into the screw hole. 1. A magnetic device comprising: an adjustment screw inserted therein; and by rotating the adjustment screw, a magnetic field applied to a device using the ferromagnetic material is adjusted.