JPS6138244Y2 - - Google Patents

Description

[Detailed Description of the Invention] This invention relates to an improvement of a Faraday rotary wave element type reversible phase shifter used in a phased array radar or the like.

First, the structure and operation of a conventional Faraday rotary wave element type reversible phase shifter will be explained, followed by a detailed explanation of this invention.

FIG. 1 shows a cross-sectional view of the structure of a Faraday rotary wave element type reversible phase shifter.

A resistive film 3 having a predetermined resistance value and an appropriate shape is deposited on one wide surface of a dielectric material 2 having a dielectric constant approximately equal to that of the ferrimagnetic material 1; Attach two dielectrics so that they are sandwiched between them.

After bonding this dielectric material and the ferrimagnetic material 1, the entire surface other than the two surfaces at both ends is plated or vapor-deposited waveguide 4 is formed by a technique such as electroless plating or vapor deposition. (Hereinafter, it will be referred to as a plated waveguide for simplicity.) Then, a permanent magnet 5, a coil 6, and a ferrimagnetic yoke 7 are arranged on this plated waveguide as shown in the figure.

Furthermore, the shield pipe 8 and the input/output waveguide 9 are electrically and mechanically bonded together using a conductive adhesive, a structural adhesive, or the like. and matching dielectric 1
The phase shifter is assembled by gluing 0's to both ends.

Next, the operating principle of the phase shifter will be explained.

The alphabetical symbols in Figure 1 are used to explain the operating functions of each part in the cross-sectional view, M ₁ and M ₂ are impedance matching parts, G ₁ and G ₂ are irreversible circularly polarized wave generators, and L ₁ , L ₂ is a linear polarizer, and F is a Faraday rotator.

The microwave signal incident from the input/output waveguide 9 on the left side is converted into a circularly polarized wave by the first irreversible circularly polarized wave generator _G1 , and then proceeds to the latching Faraday rotator F.

Ferrimagnetic material 1 of latching Farade rotator F
is magnetized to a predetermined state by the pulse current flowing through the coil 6, but the incident circularly polarized wave passes through with a transmission phase depending on the magnetization state, and is generated by the next irreversible circularly polarized wave generator _G2 . It is converted into a linearly polarized wave and becomes an output wave.

Now, assuming that the linearly polarized input wave Ein and the output wave are Eout and there is no loss, the relationship Eout=e ^-j( 〓〓 ⁺ 〓〓 ⁾・Ein...(1) holds true. Here, θ _V is the electrical length of the latching Faraday rotation wave element, and θ _F is the fixed electrical length of the other parts. Therefore, the operating principle of this phase shifter is to obtain an appropriate amount of phase shift by appropriately changing θ _V .

As described above, the strength and direction of the residual magnetization in the axial direction in the ferrimagnetic material 1 can be changed by controlling the magnitude and direction of the pulse current flowing through the coil, and as a result, θ _V can be changed.

When such a phase shifter is used in a phased array radar or the like, power durability is naturally required, but the other condition that it is reversible cannot be overlooked.

When external stress such as twisting is applied to the phase shifter,
A phase shifter that should originally be reversible may have irreversibility, but this is a phenomenon that occurs because the ferrimagnetic material 1 has a magnetostrictive effect.

Examples of ferrimagnetic materials with relatively low magnetostrictive effects include Li (lithium)-based and Mg-Mn-based ferrimagnetic materials, and pulsed microwave power is applied to a phase shifter using these ferrimagnetic materials. Increasing the peak value has the disadvantage that the insertion loss increases rapidly from a relatively low peak value. on the other hand
The peak value of the YIG (yttrium iron garnet) system can be greatly increased by adding rare earth ions such as Ho (holomyum), but there is a trade-off that it has the magnetostrictive effect. Due to this phenomenon, it was difficult to provide a phase shifter that could be put to practical use.

This invention attempts to fundamentally solve the contradictory problems mentioned above.

FIG. 2 is a diagram for explaining magnetostriction. The phenomenon in which the shape of the ferrimagnetic material 1 changes when it is magnetized by applying a magnetic field H is called magnetostriction. The length of the ferrimagnetic material before magnetization is l, the radius is a, the change length in the length direction after magnetization is △l, the change length in the radial direction is △a, and λ ₁ = △l/l and λ ₂ shows the relationship between Δa/a and the magnetic field H. According to this, the magnetic field H
The direction parallel to the magnetic field H will expand, and the direction perpendicular to the magnetic field H will contract.

Taking this one step further, in the demagnetized state, each magnetic domain is spontaneously distorted, but the directions are random and they cancel each other out, resulting in zero distortion as a whole, and as magnetization progresses, as the magnetization aligns, It is thought that the direction of strain will become uniform and deformation will appear as a whole.

When a magnetic field is applied to align the magnetization directions, the directions of distortion align, and vice versa. In other words, if the strain is equalized, the magnetization will be equalized. This is generally called the Vuilleri effect.

FIG. 3 is for explaining the phenomenon in which the phase shifter, which should be originally reversible based on the above logic, becomes irreversible due to twisting stress. In the same figure a, ferrimagnetism 1
Twisting stresses P ₁ and P ₂ are applied to rotate the A side to the left and the B side to the right. As a result, compressive forces q 1 , q ₂ and tension forces q ₃ , q ₄ act on the minute area q of any ferrimagnetic material ₁ in directions forming 45° and 135° with the long axis of the ferrimagnetic material 1, resulting in magnetostriction. Magnetization is induced in the R direction of the circumference due to the opposite effect (Wiedemann effect)
It turns out. Circularly polarized waves traveling from direction A to direction B are arrow S ₁
When incident in the direction, the RF rotating magnetic field t generates a clockwise rotating magnetic field with respect to the magnetization direction R, and exhibits a magnetic permeability μ+ of positive circular polarization.

Figure b shows the case where the torsion stresses P ₁ and P ₂ are fixed and circularly polarized waves are incident from B in the direction of arrow S ₂ in A. In this case, for the magnetization direction R
The RF rotating magnetic field t generates a counterclockwise rotating magnetic field and exhibits negative circularly polarized magnetic permeability μ-.

The fact that the magnetic permeability exhibited when a circularly polarized wave is incident from A and the magnetic permeability that is exhibited when a circularly polarized wave is incident from B are always different regardless of whether the circularly polarized wave is left-handed or right-handed is a phase shift that should be reversible. This causes the device to become an irreversible phase shifter.

In order to eliminate this problem, the magnetization component t in the circumferential direction of the ferrimagnetic material may be canceled or weakened.

FIG. 4 shows a sectional view of the ferrimagnetic material according to this invention. Numerals 11 to 14 are multi-segmented ferrimagnetic bodies, which are integrated via an adhesive layer or a dielectric layer 15 to form the ferrimagnetic body 1 of a conventional phase shifter. 4 is a plating waveguide.

With the above configuration, the closed magnetic path in the circumferential direction can be divided, the magnetization t can be weakened, and the magnetization t can be canceled by the demagnetizing field. In addition, the axial residual magnetization in the ferrimagnetic material 1 necessary to obtain an appropriate phase shift is
is hardly affected even if it is divided as in the present invention.

Figure 5 shows another embodiment of this invention, in which the cross-sectional shape of the ferrimagnetic material is square, and magnetization in the circumferential direction can be canceled by the same effect as in Figure 4, which has a circular cross-sectional shape. .

As described above, according to this invention, the ferrimagnetic material 1 is divided into a plurality of parts along the axis in the direction of propagation of circularly polarized waves, an adhesive layer or a thin dielectric layer is formed between the parts, and the parts are integrated again. The magnetization component in the circumferential direction caused by torsional stress can be canceled by the effect of the demagnetizing field.

As a result, even if a ferrimagnetic material having magnetostriction is used below the Farade rotator, it is possible to completely solve the problem that the phase shifter, which should be originally reversible, becomes irreversible due to torsional stress or the like.

This invention can solve the problem that could not be solved in terms of materials by slightly changing the structure of the Faraday rotating wave element type reversible phase shifter, and has the advantage of providing a practical Faraday rotating wave element type reversible phase shifter. The effect is huge.

[Brief explanation of drawings]

Figure 1 is a cross-sectional view of the structure of a conventional Faraday rotary wave element reversible phase shifter, Figure 2 is a diagram for explaining the effect of magnetostriction, and Figure 3 is a conventional Faraday rotary wave element type reversible phase shifter. A diagram to explain the reason for exhibiting gender,
FIG. 4 is a diagram for explaining the effect of the Faraday rotary wave element section of the Faraday rotary wave element type reversible phase shifter according to this invention, and FIG. 5 is a diagram for explaining another embodiment according to this invention. In the figure, 1 is a ferrimagnetic material, 2 is a dielectric, 3 is a resistive film, 4 is a plated waveguide, 5 is a permanent magnet, 6 is a coil, 7 is a ferrimagnetic yoke, 8 is a shield pipe, and 9 is an input/output 10 is a matching dielectric, 1
1 to 14 are multi-segmented ferrimagnetic materials according to the present invention, and 15 is a dielectric layer. It should be noted that the same or corresponding parts in the figures are indicated by the same reference numerals.

Claims (1)

[Scope of utility model registration request] In a Faraday rotary wave element type reversible phase shifter consisting of a ferrimagnetic material, a dielectric material, a resistive film, a permanent magnet, a coil, a ferrimagnetic yoke, a plated waveguide, a shield pipe, a matching dielectric material, and an input/output waveguide. ,
A Faraday rotary wave element type reversible phase shifter, characterized in that the Ferrimagnetic material is multi-divided along the direction of propagation of radio waves.