JP4223488B2 - Phaser - Google Patents

Description

  The present invention relates to a phase shifter that changes the phase of a frequency signal (for example, a microwave or millimeter wave high-frequency signal) that propagates inside a waveguide.

The phase shifter is a device that has a waveguide that constitutes a transmission line and changes the phase of the microwave that propagates inside the waveguide.
For example, a phase shifter manufactures two waveguides and requires highly precise phase alignment, or the phase of microwaves fed to a plurality of antennas, such as a phased array antenna. This is applied when the antenna beam direction is changed by controlling.

In the conventional phase shifter, toroidal ferrite is loaded inside the waveguide, but microwave reflection occurs at both ends of the toroidal ferrite due to impedance discontinuity. In order to suppress this, a rectangular dielectric impedance transformer is connected to both ends of the ferrite.
The dielectric impedance is set such that the characteristic impedance of the waveguide loaded with ferrite is Zf, the characteristic impedance of the empty waveguide is Z ₀ , and the characteristic impedance Zd of the one-stage dielectric impedance transformer is as follows: The dimensions of the body impedance transformer are determined (for example, see Non-Patent Document 1).
Zd = (Zf × Z ₀ ) ^1/2

L. R. Wicker, R.A. R. Jones, “A Digital Current Controlled Ferrite Phase Shifter”, 1965 IEEE International Convention Record, Part 5, pp. 217-223

  Since the conventional phase shifter is configured as described above, the phase of the microwave can be changed as appropriate by appropriately setting the characteristic impedance Zd of the dielectric impedance transformer. However, since it is necessary to connect the dielectric impedance transformer to both ends of the ferrite, there is a problem that the number of parts increases and the assembly becomes complicated. In addition, for example, when propagating a high-power microwave, adhesion between the dielectric impedance transformer and the ferrite may be removed due to the influence of heat, and there is a problem that reliability is lowered.

  The present invention has been made to solve the above-described problems. It is an object of the present invention to obtain a phase shifter capable of changing the phase of a frequency signal such as a microwave or a millimeter wave without mounting an impedance transformer. Objective.

  In the phase shifter according to the present invention, the dimension of the long side of the rectangular parallelepiped is set to an integral multiple of one-half of the waveguide wavelength of the waveguide, and the direction of the long side of the dielectric is the length of the waveguide. It is arranged inside the waveguide so as to coincide with the vertical direction.

  According to this invention, the dimension of the long side of the rectangular parallelepiped dielectric is set to an integral multiple of one half of the waveguide wavelength of the waveguide, and the direction of the long side of the dielectric is the length direction of the waveguide. Because it is arranged inside the waveguide so as to match, the effect of changing the phase of frequency signals such as microwaves and millimeter waves without mounting an impedance transformer There is.

Embodiment 1 FIG.
FIG. 1 is a perspective view showing a phase shifter according to Embodiment 1 of the present invention, and FIG. 2 is a sectional view showing the phase shifter according to Embodiment 1 of the present invention.
In the figure, a waveguide 1 transmits a microwave that is a high-frequency signal, and a rectangular parallelepiped dielectric 2 is disposed therein.
In the rectangular parallelepiped dielectric 2, the dimension L of the long side 2 a is set to an integral multiple of one half of the in-tube wavelength λg ₁ of the waveguide 1, and the direction of the long side 2 a is the length direction of the waveguide 1. It arrange | positions inside the waveguide 1 so that it may correspond.
However, the guide wavelength lambda] g ₁ of the waveguide 1 is the wavelength in a state where the dielectric 2 is disposed, the guide wavelength in the state where the dielectric 2 is not disposed, i.e., the guide wavelength of the recess waveguide Is represented by λg ₀ .
The dimension of the short side 2b of the dielectric 2 is set to W, and the dimension of the height of the dielectric 2 is set to H. The relative dielectric constant of the dielectric 2 is set to εr.

FIG. 3 is an equivalent circuit diagram showing the phase shifter according to Embodiment 1 of the present invention. In the figure, Z ₁ is a waveguide 1 (hereinafter referred to as a dielectric-loaded waveguide) in which a dielectric 2 is disposed. Z ₀ represents the characteristic impedance of the waveguide 1 (hereinafter referred to as a hollow waveguide) in a state where the dielectric 2 is not disposed.

Next, the operation will be described.
Since the relative permittivity εr of the dielectric 2 is set to a value higher than the relative permittivity of air or vacuum, the parallel capacitance value when the dielectric loaded waveguide is viewed as a distributed constant line is parallel to the hollow waveguide. The capacitance value becomes larger, and the characteristic impedance Z _{1 of the} dielectric-loaded waveguide becomes lower than the characteristic impedance Z ₀ of the hollow waveguide.
For this reason, since the impedance when the left side is viewed from the observation plane A in FIG. 3 is normalized by the characteristic impedance Z ₁ of the dielectric-loaded waveguide, it is expressed by Z ₀ / Z ₁ .
Since this impedance Z ₀ / Z ₁ is larger than 1, as shown in FIG. 4, it is located on the right axis from the center in the Smith impedance diagram (see the black circle in the figure).

The impedance when the right side is viewed from the observation plane B in FIG. 3 is that the dimension L of the long side 2a of the dielectric 2 is an integral multiple of one half of the waveguide wavelength λg ₁ of the waveguide 1, that is, N · Since it is equal to λg _1/2 (where N is an integer), the angle of φ = 2π × 2L / λg ₁ = N × 2π is rotated in the phase delay direction (clockwise) on the Smith impedance diagram. Come to the position to do.
However, since this impedance is an integral multiple of 2π, the impedance is the same as the impedance when the left side is viewed from the observation plane A as shown in FIG.

Normalization input impedance of the phase shifter is comprised in impedance when viewed from the right side observation surface C of FIG. 3, the reference characteristic impedance Z ₁ of normalization when viewed in the observation plane B of FIG. 3, the observation plane Since the reference characteristic impedance for normalization when viewed at C is Z ₀ , the normalized input impedance of the phase shifter is the normalized impedance Z ₀ when the impedance transformation Z ₁ / Z ₀ is viewed at the observation plane B. correspond to those subjected to / Z _1.
Therefore, as shown in FIG. 6, the normalized impedance when the right side is viewed from the observation plane C is expressed by the following equation (1), and the impedance is matched.
(Z ₁ / Z ₀ ) × (Z ₀ / Z ₁ ) = 1 (1)
This is because reflection occurs when the dimension L of the long side 2a of the dielectric 2 is set to an integral multiple of a half of the in-tube wavelength λg ₁ of the waveguide 1, ie, N · λg _1/2. This means that no phaser is obtained.

Here, FIG. 7 is a perspective view showing the waveguide 1 (phaser) in which the dielectric 2 is not arranged, and FIG. 8 shows the waveguide 1 (phaser) in which the dielectric 2 is not arranged. It is sectional drawing.
A phase difference of Δθ is generated between the phase of the signal passing through the phase shifter in FIGS. 1 and 2 and the phase of the signal passing through the phase shifter in FIGS. 7 and 8. This phase difference Δθ is expressed as the following equation (2).
Δθ = 360 ° × L × (1 / λg ₀ −1 / λg ₁ ) (2)
In the first embodiment, since L = N × λg _1/2 , Equation (2) can be rewritten as Equation (3) below.
λg ₁ / λg ₀ = 1−Δθ / (N × π) (3)

Figure 9 is a size W of the short side 2b of the dielectric 2 as a parameter, and lambda] g / lambda ₀ of the frequency characteristic (dispersion characteristic), is a graph showing the λg ₁ / λg ₀ obtained from the dispersion characteristics.
As can be seen from FIG. 9, when the dimension W of the short side 2b of the dielectric 2 is changed, the frequency characteristic (dispersion characteristic) of λg ₁ / λg ₀ of the phase shifter changes. It is understood that it can be designed to be satisfactory.
Even if the height H of the dielectric 2 and the dielectric constant εr of the dielectric 2 are changed as parameters instead of the dimension W of the short side 2b of the dielectric 2, the relationship of the expression (3) is satisfied. Can be designed as

As is apparent from the above, according to the first embodiment, the dimension L of the long side 2a of the rectangular parallelepiped dielectric 2 is set to an integral multiple of one half of the in-tube wavelength λg ₁ of the waveguide 1, Since the dielectric 2 is arranged inside the waveguide 1 so that the direction of the long side 2a coincides with the length direction of the waveguide 1, an impedance transformer is mounted. As a result, the phase of frequency signals such as microwaves and millimeter waves can be changed, and as a result, the cost can be reduced by reducing the number of parts and the assembly time can be shortened. The effect which can aim at improvement is produced.

Embodiment 2. FIG.
FIG. 10 is a perspective view showing a phase shifter according to Embodiment 2 of the present invention. In the figure, the same reference numerals as those in FIG.
In the rectangular parallelepiped ferrite 3, the dimension L of the long side 3 a is set to an integral multiple of one half of the in-tube wavelength λg ₁ of the waveguide 1, and the direction of the long side 3 a coincides with the length direction of the waveguide 1. As shown in the figure, it is arranged inside the waveguide 1.
The magnetic circuit 4 has a function of applying a magnetic field to the ferrite 3.

Next, the operation will be described.
When the magnetic circuit 4 applies a magnetic field to the ferrite 3, in the waveguide 1 in which the ferrite 3 is disposed (hereinafter referred to as a ferrite-loaded waveguide), an electron spin precession that is a source of ferrite magnetic characteristics is obtained. Due to irreversibility due to motion, a phenomenon occurs in which the guide wavelength differs in the propagation direction of the high-frequency signal.
FIG. 11 shows an equivalent circuit when a phenomenon in which the guide wavelength is different occurs. One guide wavelength is λg ₁₊ and the other guide wavelength is λg ₁₋ .

Generally, (λg ₁₊ + λg ₁₋ ) is almost unchanged at a normal magnetic field intensity that does not lead to magnetic resonance. Therefore, if L = N × (λg ₁₊ + λg ₁₋ ) / 4 = N × λg _1/2 , the same logic as the phase shifter on which the dielectric 2 is mounted as in the first embodiment. Thus, the reflection of the phase shifter on which the ferrite 3 is mounted can be reduced.
Here, λg ₁ is (λg ₁₊ + λg ₁₋ ) / 2, and is equal to the guide wavelength in a state where no magnetic field is applied.

There is a phase difference of Δθ between the phase of the signal passing through the phase shifter on which the ferrite 3 is mounted and the phase of the signal passing through the phase shifter on which the ferrite 3 is not mounted. This phase difference Δθ is expressed by the following equation (4).
Δθ = 360 ° × L × (1 / λg ₀ −1 / λg ₁₊ ) (4)
Since λg _{1+ in} Expression (4) can be controlled by controlling the magnetic field strength applied by the magnetic circuit 4, the phase difference Δθ can be controlled by the magnetic field strength. However, even if the phase difference Δθ is controlled by the magnetic field strength, the reflection is stable with a small amount as described above.

As apparent from the above, according to the second embodiment, the dimension L of the long side 3a of the rectangular parallelepiped ferrite 3 is set to an integral multiple of one half of the in-tube wavelength λg ₁ of the waveguide 1, Since it is configured to be arranged inside the waveguide 1 so that the direction of the long side 3a of the ferrite 3 coincides with the length direction of the waveguide 1, without mounting an impedance transformer, The phase of frequency signals such as microwaves and millimeter waves can be changed. As a result, the cost can be reduced by reducing the number of parts, assembly time can be shortened, and reliability can be improved. There is an effect that can be achieved.

Embodiment 3 FIG.
FIG. 12 is a perspective view showing a phase shifter according to Embodiment 3 of the present invention.
In the third embodiment, unlike the first embodiment, two rectangular parallelepiped dielectrics 2 are arranged, and the arrangement period of the two dielectrics 2 is a quarter wavelength.
In the third embodiment, a case where two dielectrics 2 are arranged will be described, but an even number of dielectrics 2 may be arranged. In this case, the arrangement period of the even number of dielectrics 2 may be an odd multiple of a quarter wavelength, that is, the arrangement period of the even number of dielectrics 2 may be (2N + 1) × λg / 4.
Further, an even number of dielectric bodies 2 (an even number of sets of dielectric bodies 2 arranged in parallel) may be disposed. In this case, an odd multiple of an even number of sets of one wavelength of the arrangement period of the dielectric 2 is 4 minutes, i.e., as long as the even sets of the arrangement period of the dielectric 2 _{(2N + 1) × λg 0} / 4.

FIG. 13 is an equivalent circuit diagram showing a phase shifter according to Embodiment 3 of the present invention.
The long sides 2 a of the two dielectrics 2 are arranged in the same direction along the length direction of the waveguide 1, and the direction of the long sides 2 a coincides with the length direction of the waveguide 1. Therefore, the transmission line of the waveguide 1 can be expressed by the susceptance B having the same value.
The susceptance B, and reflection occurs in the transmission line, since the two intervals of the dielectric 2 and the _{(2N + 1) × λg 0} /4, when the signal from the left side of the phaser is incident, left The phases of the reflected wave from the susceptance B and the reflected wave from the right susceptance B are opposite in phase on the observation plane D in FIG. 13, so the reflected waves cancel each other. For this reason, no reflection occurs in this phase shifter.
The phase difference Δθ of the phase shifter according to the third embodiment is expressed as follows.
Δθ = 2π × 2L × (1 / λg ₀ −1 / λg ₁ ) (5)

  As apparent from the above, according to the third embodiment, when the rectangular parallelepiped dielectrics 2 are arranged in an even number or even number of sets, the arrangement period of the even number or even number of dielectrics 2 is a quarter wavelength. Therefore, even when it is necessary to arrange an even number or even number of rectangular parallelepiped dielectrics 2, the phase of a frequency signal such as a microwave or a millimeter wave can be obtained without mounting an impedance transformer. There is an effect that can be changed.

Embodiment 4 FIG.
In the third embodiment, when the even number or even number of rectangular parallelepiped dielectrics 2 are arranged, the arrangement period of the even number or even number of dielectrics 2 is an odd multiple of the quarter wavelength. However, the ferrite 3 may be disposed instead of the dielectric 2.
FIG. 14 is a perspective view showing a phase shifter according to Embodiment 4 of the present invention.
In the fourth embodiment, unlike the second embodiment, two rectangular parallelepiped ferrites 3 are arranged, and the arrangement period of the two ferrites 3 is a quarter wavelength.
In the fourth embodiment, a case where two ferrites 3 are arranged will be described, but an even number of ferrites 3 may be arranged. In this case, the arrangement period of the even number of ferrites 3 may be an odd multiple of a quarter wavelength, that is, the arrangement period of the even number of ferrites 3 may be (2N + 1) × λg / 4.
Further, an even number of ferrites 3 (an even number of sets of ferrites 3 arranged in parallel) may be arranged. In this case, an odd multiple of one wavelength of the arrangement period of the even sets of ferrite 3 4 minutes, i.e., as long as the even sets of the arrangement period of the dielectric 2 _{(2N + 1) × λg 0} / 4.

As shown in FIG. 14, when two dielectrics 2 are replaced with two ferrites 3, a structure having a magnetic circuit 4 is provided as in the second embodiment.
If magnetic fields having the same strength in the same direction are applied to the two ferrites 3, the phase difference Δθ of the phase shifter is expressed as follows.
Δθ = 2π × 2L × (1 / λg ₀ −1 / λg ₁₊ ) (6)
Since λg _{1+ in} Equation (6) can be controlled by controlling the magnetic field strength applied by the magnetic circuit 4, the phase difference Δθ can be controlled by the magnetic field strength. However, even if the phase difference Δθ is controlled by the magnetic field intensity, the reflection is stable while being small.

  As can be seen from the above, according to the fourth embodiment, when an even number or even number of rectangular parallelepiped ferrites 3 are arranged, the arrangement period of the even number or even number of ferrites 3 is an odd number of a quarter wavelength. Since it is configured to be double, even if it is necessary to arrange an even number or even number of rectangular parallelepiped ferrites 3, the phase of a frequency signal such as a microwave or millimeter wave is changed without mounting an impedance transformer. There is an effect that can be.

It is a perspective view which shows the phase shifter by Embodiment 1 of this invention. It is sectional drawing which shows the phase shifter by Embodiment 1 of this invention. It is an equivalent circuit diagram which shows the phase shifter by Embodiment 1 of this invention. It is a Smith impedance figure which shows the normalized impedance when the left side is seen from the observation surface A. It is a Smith impedance figure which shows the normalized impedance when the right side is seen from the observation surface B. It is a Smith impedance diagram which shows the normalized impedance when the right side is seen from the observation surface C. It is a perspective view which shows the waveguide (phaser) by which the dielectric material is not arrange | positioned. It is sectional drawing which shows the waveguide (phaser) in which the dielectric material is not arrange | positioned. Frequency characteristics of the lambda] g ₁ / lambda] g ₀ phaser according to Embodiment 1 of the present invention is a graph showing (dispersion characteristic). It is a perspective view which shows the phase shifter by Embodiment 2 of this invention. It is an equivalent circuit diagram which shows the phase shifter by Embodiment 2 of this invention. It is a perspective view which shows the phase shifter by Embodiment 3 of this invention. It is an equivalent circuit diagram which shows the phase shifter by Embodiment 3 of this invention. It is a perspective view which shows the phase shifter by Embodiment 4 of this invention.

Explanation of symbols

1 Waveguide, 2 Dielectric, 2a Long side, 2b Short side, 3 Ferrite, 3a Long side, 4 Magnetic circuit.

Claims (4)

  The waveguide for transmitting the frequency signal and the length of the long side are set to an integral multiple of one-half of the waveguide wavelength of the waveguide, and the direction of the long side matches the length direction of the waveguide. A phase shifter including a rectangular parallelepiped dielectric disposed inside the waveguide. 2. The phase shifter according to claim 1, wherein when an even number of rectangular parallelepiped dielectrics are arranged , the arrangement period of the even number of dielectrics is an odd multiple of a quarter wavelength.   The waveguide for transmitting the frequency signal and the length of the long side are set to an integral multiple of one-half of the waveguide wavelength of the waveguide, and the direction of the long side matches the length direction of the waveguide. A phase shifter including a rectangular parallelepiped ferrite disposed inside the waveguide and a magnetic circuit for applying a magnetic field to the ferrite. 4. The phase shifter according to claim 3, wherein when an even number of rectangular parallelepiped ferrites are arranged, the arrangement period of the even number of ferrites is an odd multiple of a quarter wavelength.

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