JPH05121902A - Phase shifter - Google Patents

Abstract

PURPOSE:To realize the phase shifter changing continuously a phase of a transmission signal or controlled remotely. CONSTITUTION:An input terminal of a stub formed by slidably inserting in the axial direction a moving cylinder 3 made of a solid dielectric substance between an outer conductor 1 and an inner conductor 2 from one end of a coaxial line comprising the outer conductor 1 and the inner conductor 2 is connected to a coupling circuit 4 such as a directional coupler, a circulator or a hybrid circuit.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a phase shifter for various electric or electronic circuits in the ultra-high frequency or microwave band.

[0002]

2. Description of the Related Art A phase shifter conventionally used in various electric or electronic equipment circuits in the ultra-high frequency or microwave band, for example, a shifter used to change the feeding phase of each element antenna constituting a beam tilt antenna. The phaser is configured so that, for example, four transmission lines having different lengths from each other are selectively inserted into the power supply line by switching the changeover switch.

[0003]

The above-mentioned conventional phase shifter requires a plurality of transmission lines and changeover switches having different lengths from each other, so that not only the structure becomes complicated and large, but also the feeding phase is changed. It cannot be changed continuously.

[0004]

According to the present invention, a movable cylindrical body made of a solid dielectric is axially slidably inserted from one end of a coaxial line composed of an outer conductor and an inner conductor. And a coupling circuit such as a directional coupler, a circulator or a hybrid circuit to which the input ends of the stubs are connected. This is what you are trying to do.

[0005]

When the insertion length of the movable cylindrical body made of the solid dielectric between the outer conductor and the inner conductor forming the coaxial line is changed, the phase angle of the input reflection coefficient in the stub changes, and therefore the phase shifter of the present invention. Is coupled to the transmission line, the phase of the transmitted signal changes.

[0006]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 is a partial cross-sectional view showing an essential part of an embodiment of the present invention, in which 1 is a cylindrical outer conductor and 2 is a rod-shaped or relatively thin cylindrical inner conductor. A coaxial line is formed by the conductor. The outer conductor 1 and the inner conductor 2 can be embodied in a cross-sectional shape in a circular shape or in a rectangular shape or in one of them in a circular shape and the other in a rectangular shape. Reference numeral 3 denotes a movable cylindrical body made of a solid dielectric. The shape of the outer peripheral edge of the movable conductor 3 is made substantially the same as the shape of the inner peripheral edge of the outer conductor 1 in the transverse section thereof. The shape of the inner peripheral edge is the inner conductor 2
Of the outer peripheral edge in the cross section of the solid conductor, the movable cylindrical body 3 made of a solid dielectric is made to have an appropriate thickness, and the movable cylindrical body 3 made of a solid dielectric is placed between the outer conductor 1 and the inner conductor 2. Is formed so as to be slidable in the axial direction. Reference numeral 4 denotes a coupling circuit with an external circuit, which is composed of, for example, a directional coupler, a circulator or a hybrid circuit.
Although not shown in FIG. 1, for example, a pulse motor is coupled to the outer end of the movable cylindrical body 3 made of a solid dielectric through, for example, a rack and a pinion to rotate the pulse motor in the forward or reverse direction. Accordingly, the movable cylinder 3 made of a solid dielectric is moved forward or backward so that the axial length of the insertion of the movable cylinder 3 made of a solid dielectric between the outer conductor 1 and the inner conductor 2 can be continuously and finely controlled. To configure.

The axial length of a portion in which air is interposed without inserting the movable cylindrical body 3 made of a solid dielectric between the outer conductor 1 and the inner conductor 2 is L _A , and the characteristic impedance is Z _A , The characteristic admittance is represented by Y _A , the basic matrix is represented by [F _A ], the axial length of the inserted portion of the movable cylinder 3 made of a solid dielectric is L _D , the characteristic impedance is Z _D , and the characteristic admittance is When Y _D and the basic matrix are represented by [F _D ], the basic matrix [F _AD ] of the stub composed of the outer conductor 1, the inner conductor 2, and the movable cylindrical body 3 made of a solid dielectric is represented by the following equation.

[0008]

[Equation 1] In the formula (1), m _A = 2π / λ _A λ _A : In-tube wavelength in a portion where the movable cylinder 3 made of solid dielectric is not inserted m _D = 2π / λ _D λ _D : movable made of solid dielectric In-tube wavelength at the portion where the cylindrical body 3 is inserted

The complex reflection coefficient Γ when the load Z _L is connected to each right end portion (the end portion on the right side in FIG. 1) of the outer conductor 1 and the inner conductor 2 forming the stub is the power source impedance.
If the dance is Z _O , it can be calculated by the following formula.

[Equation 2] The complex reflection coefficient Γ _O when the load Z _{L is set} to infinity, that is, when the right end portions of the outer conductor 1 and the inner conductor 2 are opened is calculated by the following equation. Dividing the numerator and denominator on the right side in equation (2) by Z _L gives

[Equation 3] If Z _L in the above equation is infinite,

[Equation 4] The phase angle θ _O of the complex reflection coefficient Γ _O is expressed by the following equation.

[Equation 5] As is clear from the above equations, when the insertion length L _D of the movable cylindrical body 3 made of a solid dielectric is changed, the absolute value of the complex reflection coefficient Γ _O is 1, and only the phase angle θ _O can be changed. That is, only the phase of the reflected wave can be changed without causing reflection loss.

FIG. 2 shows a coupling circuit 4 in the case where the coupling circuit 4 shown in FIG. 1 is constituted by a directional coupler, for example, a directional coupler having a mutual phase difference of 90 ° and a coupling degree of approximately 3 dB. 2 is a diagram for explaining the electrical characteristics of FIG.
DCP is a directional coupler, T ₁ is an input terminal, T ₂ is a direct terminal, T ₃ is a coupling terminal, and T ₄ is an isolation terminal.
When the voltage coupling coefficient of the directional coupler DCP is C _C and the electrical angle of the coupling line section is θ _C , the scattering matrix [S] of this directional coupler is expressed by the following equation.

[0011]

[Equation 6] In equation (5),

[Equation 7]

[0012] Each output voltage of from the terminal T ₁ in the case of applying input voltage E _i to the terminal _{T 1 T 4 E O1, E} O2, E O3 and E
_O4 is _calculated by the following equation.

[Equation 8]

FIG. 3 is an equivalent circuit diagram of FIG. 1, that is, an equivalent circuit diagram when the coupling circuit 4 of FIG. 1 is configured by the directional coupler described in FIG. 2, and STB is the outer conductor 1 in FIG. , A movable cylindrical body 3 composed of an inner conductor 2 and a solid dielectric
The other reference numerals are the same as those in FIG. Applying an input voltage E _i to terminal T ₁ of the directional coupler DCP
Reflected voltages E _2R and E _3R shown in the following equation appear at T ₂ and T ₃ .

[Equation 9]

[0014] Thus, the output voltages of from terminals T ₁ in the case of applying input voltage E _i to the terminal T ₁ T ₄ E _O1S,
E _O2S , E _O3S and E _O4S are _calculated by the following equations.

[Equation 10]

From equations (7), (8) and (9), the terminal
_Determine the output voltage E _O1S and E _O4S of T ₁ and T ₄ , and determine the directional coupler.
DCP voltage coupling coefficient C _C

[Equation 11] With placing and the electrical angle theta _C coupled line portion in the directional coupler DCP as 90 °, and rearranging the equation representing the output voltage E _O1s and E _O4S, the output voltage E _O1s and E _O4S is represented by the following formula It

[Equation 12] That is, the voltage applied to the terminal T ₁ (or T ₄ ) is not lossy and only the phase changes by θ _O.
4 (or T ₁ ) and no reflected voltage appears at terminal T ₁ (or T ₄ ).

FIG. 4 is a sectional view showing a main part of another embodiment of the present invention (a sectional view taken along the line XX in FIG. 5). FIG. 5 is a rear view. In both figures, 1 is an outer conductor and 2 is Inner conductor, 3 is a movable cylinder made of solid dielectric, 4 is a coupling circuit, 5 is a short-circuit conductor,
The outer ends of the outer conductor 1 and the inner conductor 2 are electrically short-circuited. Reference numeral 6 denotes a notch, which is provided over the axial length from the outer end of the side wall portion of the movable cylindrical body 3 made of a solid dielectric and corresponding to the location where the short-circuit conductor 5 is provided, and the width of the notch 6 Is appropriately larger than the width of the short-circuit conductor 5. In this embodiment, a short-circuit stub is formed by the outer conductor 1, the inner conductor 2, and the movable cylinder 3 made of a solid dielectric, and the notch 6 provided on the side wall of the movable cylinder 3 made of the solid dielectric is a short-circuit conductor. Since the width of the notch 6 corresponds to the position of 5 and is appropriately larger than the width of the short-circuit conductor 5, there is no possibility that the sliding of the movable cylindrical body 3 made of a solid dielectric material in the axial direction is disturbed. Also in this embodiment, an axial drive element is provided at the outer end of the movable cylindrical body 3 made of a solid dielectric, as in the previous embodiment.

Since the stub in this embodiment is a short-circuit type stub, the load Z _L in equation (2) is zero, and therefore the complex reflection coefficient Γ _S and the complex reflection coefficient Γ _{S in} this case.
The phase angle θ _S of each is expressed by the following equation.

[Equation 13] In this embodiment, the output voltages E _O1S and E _O4S can be obtained by replacing the complex reflection coefficient Γ _O in the expressions (10) and (11) with Γ _S.

FIG. 6 shows an example of the relationship between the insertion length of the movable cylindrical body 3 made of a solid dielectric and the phase angle θ _O of the complex reflection coefficient Γ _O in each of the embodiments shown in FIGS. 1, 4 and 5. And the complex reflection coefficient Γ _{S of the} movable cylinder 3 made of solid dielectric
Of the relationship between the phase angle θ _S and the phase angle θ _S , respectively, based on theoretical calculation values. The horizontal axis represents the insertion length L _D (mm) of the movable cylinder 3 made of a solid dielectric, and the vertical axis represents the phase. Angle θ _O or θ _S (d
eg). Curve showing phase angle θ _O and phase angle θ
_In each of the curves showing the change in _S, the axial length of the outer conductor 1 and the inner conductor 2 is 400 mm, and the characteristic impedance Z _A is 50.
Ω, the relative permittivity of the movable cylinder 3 made of a solid dielectric is 2.3,
The frequency used is 750 MHz.

FIG. 7 is also an equivalent circuit diagram of another embodiment of the present invention, that is, an embodiment in which the coupling circuit 4 in FIG. 1 is formed by a circulator, where CCL is a circulator, STB.
Is an open stub similar to that described for FIG.
The voltage applied to the input terminal T _C1 of the circulator CCL is applied to the open stub STB from the output terminal T _C2, and the reflected wave at the open stub STB is _sought via the terminal T _C2.
In addition to curator CCL, isolation terminal T _C3
Is output from. The voltage output from the terminal T _C3 is the same as in the embodiment shown in FIG. 1 in that only the phase changes by the phase angle θ _O of the complex reflection coefficient Γ _O without loss. Of course, the present invention can be implemented by replacing the open stub STB in FIG. 7 with the short-circuit stub described with reference to FIGS. 4 and 5.

In addition to using the above-mentioned coupling circuit as the coupling circuit 4 in FIG. 1, for example, a TEM transmission line or a quasi-TEM
A directional coupler formed of transmission lines or a TEM transmission line or a hybrid circuit formed of quasi-TEM transmission lines may be used. Further, the above description has been made of the case where the movable cylindrical body 3 made of a solid dielectric is driven in the axial direction by, for example, a rack, a pinion and a pulse motor, but it may be driven manually.

[0021]

The phase shifter of the present invention has a relatively simple structure,
It has features such that the phase of the input voltage can be continuously changed, and the drive of the movable cylindrical body 3 made of a solid dielectric can be controlled from a remote location. It is very effective when used as a phase shifter.

[Brief description of drawings]

FIG. 1 is a view having a partial cross section showing a main part of an embodiment of the present invention.

FIG. 2 is a diagram for explaining an example of characteristics of a coupling circuit in the phase shifter of the present invention.

FIG. 3 is an equivalent circuit diagram of the phase shifter of the present invention.

FIG. 4 is a partial cross-sectional view showing the main part of another embodiment of the present invention.

FIG. 5 is a rear view showing the main part of another embodiment of the present invention.

FIG. 6 is a curve diagram showing an example of characteristics of the phase shifter of the present invention.

FIG. 7 is an equivalent circuit diagram showing another embodiment of the present invention.

[Explanation of symbols]

1 outer conductor 2 inner conductor 3 movable cylinder made of solid dielectric 4 coupling circuit DCP directional coupler T ₁ input terminal T ₂ direct terminal T ₃ coupling terminal T ₄ isolation terminal STB stub 5 short-circuit conductor 6 cut CCL support − Curator T _C1 input terminal T _C2 output terminal T _C3 isolation terminal

Claims (6)

[Claims] 1. A stub comprising a movable cylindrical body made of a solid dielectric material inserted axially slidably between the outer conductor and the inner conductor from one end of a coaxial line made up of the outer conductor and the inner conductor. Phase shifter characterized by. 2. The phase shifter according to claim 1, wherein the stub is an open stub. 3. The phase shifter according to claim 1, wherein the stub is a short-circuit stub. 4. A stub in which a movable tubular body made of a solid dielectric is axially slidably inserted between one end of a coaxial line made of an outer conductor and an inner conductor so as to be slidable in the axial direction. And a directional coupler to which an input end of the phase shifter is connected. 5. A stub in which a movable tubular body made of a solid dielectric is axially slidably inserted between one end of a coaxial line composed of an outer conductor and an inner conductor, the stub being slidable in the axial direction between the outer conductor and the inner conductor. And a circulator to which an input end of the phase shifter is connected. 6. A stub in which a movable tubular body made of a solid dielectric is axially slidably inserted between one end of a coaxial line composed of an outer conductor and an inner conductor, the stub being slidable between the outer conductor and the inner conductor. And a hybrid circuit to which the input end of is connected.