JPS63224501A - Phase shifter - Google Patents

Abstract

PURPOSE:To obtain a prescribed phase change by providing stubs on a microwave transmission line at an equal interval and adjusting the length respectively so as to lower the fluctuation of the standing wave ratio. CONSTITUTION:Three stubs STUB 2, 3, 4 whose length is made variable are arranged on the microwave transmission line 1 at an equal interval l0. Then the phase shift quantity is adjusted by adjusting lengths l1, l2 of each variable stub to attain the prescribed phase change.

Description

[Detailed Description of the Invention] (Industrial Application Field) The present invention is a microwave phase adjustment circuit, more specifically, it is equipped with three adjustment stubs, and it is considered to reduce fluctuations in the standing wave ratio. This relates to a phase shifter.

(Prior Art) A conventional phase shifter of this type was composed of two stub lines placed 14 wavelengths apart on a microwave transmission circuit.

(Problems to be Solved by the Invention) The above-mentioned conventional two-stub phase shifter has the drawback that the phase amount is set by adjusting the length of the stub line, and the 9% standing wave ratio also fluctuates considerably at the same time. Ta.

FIG. 3 is a configuration diagram showing an example of a conventional two-stub system, and V% FIG. 4 shows its equivalent circuit. In FIG. 3, 11 is the main body of the microwave transmission circuit, 12 is the first stub with length Ll, 13 is the second stub t with length L2, and the interval between the first stub 12 and the second stub 13 is I.
l.

It is.

In the equivalent circuit shown in FIG. 4, the F parameter t- is expressed.

7? :% input impedance Zinij (m +Zo
Yt ) in θ can be expressed as (2).

Since A-D is necessary for Zin m to be 1, (2) θ+j (
ZoYz+1)dnθ-(Y1+Y2+1)ccm
o+3(z.

+ZOYIY2+ZOYl ) mθ (-〇2-tl!101) θ+jl-θ10-θ2)
The cluster θ−°θ1−02gtnθ)−〇 becomes・(
Therefore, the following relationship is required for the above formula to hold true.

In other words, in the conventional phase shifter with two stubs, Z in
w l is θ1−θ2. and 2 ugly θ−−θ
Only when 1. From this state, when the length of the stub is completely changed in the ninth stage of phase adjustment for the phase shift of Δφ, θ! and θ2 changes, the above conditions are broken, and the standing wave ratio inevitably changes as one phase changes.

An object of the present invention is to provide a phase shifter that can obtain a predetermined phase change while keeping fluctuations in the standing wave ratio small.

problem? Elaborate Means for Solving the Problem] To achieve the above object, the phase shifter according to the present invention has three variable length stubs distributed at equal intervals on the microwave transmission circuit, and the length of the variable stubs is The configuration is such that the phase shift tv is adjusted by adjusting the phase t to obtain a predetermined phase change.

(Example) Next, one embodiment of the present invention will be explained with reference to all the drawings.

FIG. 1 is a block diagram showing an embodiment of a phase shifter according to the present invention.

In the figure, l is the main body of the microwave transmission circuit, 2 is the length I
tl is the first stub ($x8TuB), 3 is the second stub (#: 28TUB) with length ft2, and 4 is the third stub (#-38TTJB) whose length is equal to the first stub length 21. These three stubs 2°3.4 are arranged at intervals of IIO.

FIG. 2 is an electrical equivalent circuit of the microwave transmission circuit indicated by xliN.

The F parameter of this equivalent circuit is expressed as follows.

-) (Yx''+YtYznZoa2θ) Also, if the input impedance is eZin, it is expressed as.

At the center frequency Fo of operation of this phase shifter.

In the hole where Zin is equal to the normalized impedance 1, since it is A-D, it must be C-B.

In order to become C and B, " * '" * j! z
Electrical angle θ, θ1. θ2 must satisfy the following relational expression.

1θ1 (2G11g2θ-self2θ-θ1)+-θz(
(mθ−θl−■θ)+−θ) Seal O・・・・・・・・・
...(3) If the transfer phase constant tφ of this circuit is φ
= Arg (A+B+C+D) °°°゛°”°
“°”” (represented by 4+).

Since A-D and B-C, φ becomes the following formula.

-ab) ・・・・・・・・・・・・・・・River...
...1 old... shout... (51fifLAayt-θ
1. bMm-θ2.

The phase constant for the required phase shift amount Δφ is φ+Δφ. At this time, θ is fixed, so θl and 02 Th(
If it is determined to satisfy Equation 31 and Equation (5), even if the phase is shifted by Δφ, the standing wave ratio at the center frequency remains 1 and does not change.

As described above, the g-foot wave ratio change wJ can be suppressed to a low level by the action of the second stub in the three-stub configuration.

(Effects of the Invention) As explained above, the phase shifter according to the present invention is configured such that three stubs are provided at equal intervals on the microwave transmission line, and the length of each stub is adjusted. Therefore, it has a phase variable width of the amount of phase noise.

Moreover, there is an effect that fluctuations in the standing wave ratio at that time can be suppressed to a low level.

[Brief explanation of the drawing]

FIG. 1 is a configuration diagram showing an embodiment of a phase shifter according to the present invention;
The second prisoner is an electrical equivalent circuit diagram of the phase shifter shown in No. 10,
FIG. 3 is a block diagram of a conventional phase shifter, and FIG. 4 is an equivalent circuit diagram of the phase shifter shown in FIG. 1.11... Microwave transmission line body 2.12... First stub (length 11) 3.13...
Second stub (length L2) 4...Third stub (length jl
t) Patent applicant Nippon Electric Radio Equipment Engineering Co., Ltd. Agent Patent attorney Inoro Bakusai Is, t2 Uchisai 3 Figure 24 Figure θ

Claims (2)

[Claims] (1) Three variable-length stubs are arranged at equal intervals on the microwave transmission circuit, and the amount of phase shift is adjusted by adjusting the length of the variable stubs to obtain a predetermined phase change. A phase shifter characterized in that it is configured as follows. (2) The phase shift according to claim 1, wherein the microwave transmission circuit is a transmission line constituted by a strip line, and the three length variable stubs are open stubs having a strip line configuration. vessel.