RU1781744C - Magnetic system - Google Patents

Description

1

(21) 4787140/09

(22) 2901 90

(46) 15.1292 Bull. Ms 46

(71) Saratov branch of the Institute of Radio Engineering and Electronics, USSR Academy of Sciences

(72) V. V. Tikhonov. A B Tolkachev, B. V. Semen and B. K. Ostariichuk

(56) Copyright certificate of the USSR No. 513396, cl. H 01 F 7/00, 1976.

USSR copyright certificate No. 951208, cl. G 01 R 33/05, 1982.

(54) MAGNETIC SYSTEM

(57) Use: the invention relates to radio engineering and can be used in ferrite microwave devices. SUMMARY OF THE INVENTION A magnetic system comprising a first steel plate on which permanent magnets are mounted on the first poles of the same name on the opposite side of the working gap and a second steel plate parallel to the first and placed on the second surface of the same constant magnet poles is supplemented with nn | e magnets, a third steel plate and screen, with additional permanent magnets mounted by second poles of the same name on the opposite surface of the second steel plate, their first poles of the same name are connected by a third steel plate, the first and third steel plates are connected to the screen, between the second steel plate and the screen clearance is completed. The width of the gap, magnetization and pole area of the additional magnets are selected in accordance with the relationships given in the claims. To adjust the floor in the working gap in the hole made in the third steel plate opposite the working gap, an adjustment screw is installed, and turns of the control coil are placed between the screen and the magnets. 1 C.p. f-ls, 1 ill.

The invention relates to radio engineering and can be used in ferrite microwave devices.

A magnetic system is known, consisting of several wedge-shaped permanent magnets creating a reinforced field in the working gap formed by these magnets.

A magnetic system is also known, consisting of a U-shaped magnetic core and a permanent magnet located inside it, opposite which screws are installed to adjust the magnitude and topology of the field.

However, these structures are not protected against external magnetic fields and are strongly

 00

shunted by surrounding steel objects. In addition, the first structure has no adjustment of the floor in the working gap, and the second is characterized by a high complexity of adjustment.

Closest to the present invention is a magnetic system comprising a first steel plate on which permanent magnets are mounted on the first poles of the same name on the opposite side of the working gap, and a second steel plate parallel to the first and placed on one surface on the second permanent poles of the same magnets. The change in the magnitude of the field in the working gap between the plates is carried out using steel shunts on the outer side surfaces of the permanent magnets.

A disadvantage of this design is also the lack of self-protection against external magnetic fields, and its shielding can be achieved only by a multiple increase in size, or by weakening the floor in the working gap.

The aim of the invention is to protect against external magnetic fields while maintaining the field in the working gap, as well as mechanically and electrically adjusting the floor in the working gap.

This goal is achieved by the fact that in the known magnetic system comprising a first steel plate, on which the first poles of the same name are mounted permanent magnets on different sides of the working gap, and a second steel plate parallel to the first and placed on one surface on the second poles of the same permanent magnets, additional permanent magnets are introduced, a third steel plate and shield, while additional permanent magnets are installed by the second permanent magnets of the same name on the opposite surface five second steel plate, like poles of the first steel plate are connected by a third, the first and third steel plates connected with the screen, between the second steel plate and screen a gap width h which satisfies the following condition: 5b

h.d

S7

(1)

where d is the distance between the first and second steel plates;

So is the area of the second steel plate;

5b - the area of the lateral surface of the second steel plate; and the magnetizations Mi and the area of the poles Si i-x of the additional magnets are selected from the condition;

d l (Mi Sil) d Ј (MjSj), (2)

1 1j-1

where d1 is the distance between the second and third steel plates;

i.e. the number of additional permanent magnets:

n is the number of permanent magnets;

Mj and Sj are the magnetization and pole area of the j-ro permanent magnet, respectively.

This goal is also achieved by the fact that a hole is made in the third steel plate opposite the working gap, in which an adjusting screw is installed, and turns of the control coil are placed between the screen and the magnets.

The drawing shows the design

proposed magnetic system.

The magnetic system consists of the first 1 and second 2 steel plates, between which the permanent magnets 3 are located. It also contains additional magnets 4 (the directions of magnetization of the main and additional magnets are shown by arrows), a third steel plate 5 and a screen 6. In the hole of the third plate 5 set the adjusting screw 7,

5a, a control coil 8 with a wire is installed in the gap between the screen 6 and magnets 3-4. A ferrite device 9 is installed in the working gap between the plates 1 and 2, the input of the microwave energy output is carried out through holes in the first steel plate 1. In the same plate 1 there are holes for power supply 11 of the coil 8, the magnetic system has a microstrip hinged structure the lines

5 gears. It is mounted on the dielectric substrate 12 from the side of the metallized surface 13. The input and output of the microwave 10 and the power leads 11 of the coil 8 pass through the holes in the substrate 12 and are connected to the strip lines 14 located on the back of the substrate 12.

The magnetic system operates as follows.

The main 3 and additional 4 permanent magnets create magnetic fluxes, which, when summed up, enter the second steel plate 2, then separate and close to the third steel plate 5 through the working gap between the plates and

0 through the adjustment gap between the third plate 5 and the reverse surface of the second plate 2. At the same time, a difference magnetic flux flows through the screen 6. This flow is equal to zero when equality in relation (2) is satisfied. The absence of magnetic flux in the screen 6 means the absence of the shunting action of the third plate 5. In this case, in the working gap between the plates 1 and 2, the field is set:

04l: D,

In «(MjSj), (3)

 J 1

equal to the maximum field in the design of the prototype. Inequality in relation (2)

e corresponds to additional reinforcement of the floor in the proposed design. The gap between the magnets 3-4 (i.e. the side surface of the second plate 2) and the screen 6 prevents the floor in the working gap from decreasing due to stray magnetic closure

flow to the screen 6 through the lateral surface of the second plate 2. The gap h is selected by their conditions, where Rn h / Se is the spurious magnetic resistance and a is the magnetic resistance of the working gap. Given that, we obtain relation (1). The insertion of the adjusting screw 7 into the housing corresponds to a decrease in the magnetic resistance of the adjusting gap. In this case, most of the magnetic flux is directed through this gap. In this case, a shunting effect occurs, reducing the field in the working gap. By touching the screw 7 of the surface of the second plate 2, the field in the working gap decreases to a minimum value close to zero. A control coil 8 with a wire passing electric current creates an additional magnetic flux in the working gap of the magnetic system, which, depending on the direction of the current, is either added or subtracted from the magnetic flux created by the permanent magnets. In this case, the field in the working gap either decreases or increases relative to a certain value set by the adjusting screw 7. To connect the ferrite device to the strip circuit, the magnetic system is mounted on the dielectric substrate 12 of the microstrip transmission line from the metallized surface 13, input and the output of the microwave 10 and the conclusions of the coil 11 are connected through the holes in the substrate to the strips 14 and connected to them, the strips connected to the terminals 10 are connected to the microwave path, and the strips are connected with pin 11, - a source control TO- ka.

The invention is as follows. The manufactured magnetic system contains one main 3 and one additional 4 magnets with the same characteristics and sizes. They are made of samarium-cobalt alloy in the form of rings with an inner diameter of 8 mm, an outer diameter of 12 mm and a thickness of 1.5 mm. The second steel plate 2 has a disk shape with a diameter of 12 mm and a thickness of 1 mm. The first steel plate 1 in the form of a disk 21 mm in size and 2 mm thick has four holes with a diameter of 1.5 mm, two of which are for input and output of the microwave 10, and two are for powering the coil 11 8. The third steel plate 5 and the screen 6 have a cylindrical shape with a diameter of 21 mm and a height of 6 mm. The inner diameter of the shield 6 is 18 mm and its wall thickness is 2 mm. In the third plate 5 along the axis of symmetry there is a threaded hole with a diameter of 0.5 Mb, into which an adjustment screw 7 is screwed 2.5 mm long. Coil 8 has a ring shape with an outer diameter of 18 mm, an inner diameter of 12 mm and a height of 4 mm. Coil 8 has approximately 100 turns of wire 0.25 mm thick; its resistance is 7 G et 3 Ohms. The overall dimensions of the system are 2 21 8 mm2.

The magnetic system was tested using a ferrite film resonator 9, which was placed in the working gap inside the main ring magnet. The dependence of the resonance frequency on the mechanical and electrical control of the field was measured. Mechanical adjustment with screw 7 made it possible to tune the resonator frequency from a minimum excitation frequency of 300 MHz to 4 GHz, which corresponded to a change in the field in the working gap from 7 kgf to .2 kgf. Electrical adjustment made it possible to tune the resonator frequency within ± 1 GHz, which corresponded to an addition to the field established by mechanical adjustment of approximately ± 0.3 kgf. At the same time, the power consumption of the coil did not exceed 1 W / kgf.

In the proposed design of the magnetic system, protection from external fields and shunting steel objects slightly, less than Twofold, increased the overall dimensions of the system while maintaining the maximum floor in the working gap. In addition, the protection system made it possible to additionally introduce mechanical and electrical adjustment of the floor without an additional increase in dimensions.

Claims (2)

1. A magnetic system comprising a first steel plate on which permanent magnets are installed on the opposite sides of the working gap by the first poles of the same name, and a second steel plate parallel to the first and placed by one surface on the second permanent poles of the same name, characterized in that, in order to protect against external magnetic fields while maintaining the field in the working gap, additional permanent magnets, a third steel plate and a shield were introduced, while additional permanent magnets installed us second like poles on the opposite surface of the second steel plate, like poles of the first steel plate are connected by a third, the first and third steel plates connected with the screen, between the second steel plate and screen a gap width h which satisfies a condition .. bo where d is the distance between the first and second steel plates; So is the area of the second steel plate; 5b — the area of the lateral surface of the second steel plate, the magnetization M and the area of the poles of Si additional magnets are selected from the condition. d f (Ml Sited | (MjSj) e Y // 7/77 //// 17 / 0 5 where d1 is the distance between the second and third steel plates; m is the number of additional permanent magnets; n is the number of permanent magnets; Mj and Sj are the magnetization and pole area of the J-ro permanent magnet, respectively. 2. The system for years. 1, characterized in that, for the purpose of mechanically and electrically adjusting the floor in the working gap, a hole is made in the third steel plate opposite the working gap in which the adjusting screw is installed, and coils of the control coil are placed between the screen and the magnets. 7 // U777 /