JP3095676B2 - Non-contact type coupling circuit - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a non-contact type coupling circuit. In particular, the present invention relates to a non-contact type coupling circuit capable of continuously changing the phase of a high-frequency signal.

[0002]

2. Description of the Related Art Various types of phase shifters for continuously changing the phase of a high-frequency signal have been proposed.

As a typical example, there is a line stretcher system constituted by a coaxial tube. This changes the phase of the high-frequency signal by sliding the outer conductor and the inner conductor of the coaxial waveguide to each other and changing the length.

[0004]

In this type of phase shifter, the outer conductor and the inner conductor slide with respect to each other.
Poor contact may cause noise and intermodulation problems.

By transmitting signals having different phases to each antenna element of an array antenna in which a plurality of antenna elements are arranged, the direction of the main lobe of radiation from the array antenna can be changed. At this time, if a structure is adopted in which a line stretcher is connected for each cable that supplies power to each element,
The length of each line has to be finely adjusted, resulting in poor workability and high cost.

SUMMARY OF THE INVENTION An object of the present invention is to provide a phase shifter capable of continuously changing the phase with little noise generation and intermodulation due to poor contact, good workability, and low cost. Another object of the present invention is to propose a non-contact type coupling circuit having a large range in which the phase of a signal can be varied when used as a phase shifter.

[0007]

The object of the present invention is to provide a dielectric substrate, a conductor film covering a lower surface of the dielectric substrate, and an input strip line provided on the upper surface of the dielectric substrate and having an input terminal at one end. A rotating coupling conductor rotatable about the other end on the input side strip line, one end of which is coupled to the input side strip line via an insulator; and A non-contact type coupling circuit comprising an output side strip line coupled to the other end of the rotary coupling conductor via an insulator, having an output terminal at both ends and formed in an arc shape having the other end as a center, when the wavelength of the rotary coupling conductor corresponding to the operating frequency and lambda] g, the position of the lambda] g / 4 from the other end which is coupled with the output side strip line of the rotational coupling conductor
Forming a wide portion wider than the width of the rotation coupling conductor,
A load impedance circuit is provided in a section from the wide portion to the other end, a characteristic impedance Z _IN from the one end of the rotary coupling conductor to the load impedance circuit, an equivalent characteristic impedance of the load impedance circuit as Z ₀ , when the impedance from the load impedance viewed the output side strip line and Z _L, which is solved by a non-contact coupling circuit characterized by satisfying the relation of Z ₀ is approximately ^{_{Z iN Z L = Z 0 2}} .

[0008]

[Operation] A signal sent from an input side strip line is sent to an output side strip line through a rotary coupling conductor and output from output terminals at both ends of an output side strip. That is, the non-contact type coupling circuit according to the present invention functions as a branch circuit.

By rotating the rotation coupling conductor, the coupling position between the rotation coupling conductor and the output side strip line changes. As a result, the phase of the output signal from one output terminal of the output side strip line advances, and the phase of the output signal from the other output terminal delays.

When the output side strip line is viewed from the rotation coupling conductor, two load circuits are connected in parallel, so that the output impedance is reduced. A load impedance circuit as a quarter-wave transformer is provided on the output side strip line side of the coupling element in order to match the characteristic impedance of the input side strip line side portion of the rotary coupling conductor. The operation of the quarter-wave λ transformer is well known and will not be described. Note that the wavelength λg of the strip line is determined by various parameters such as the frequency and the dimensions of the strip line. Therefore, λg in the load impedance circuit is determined by the above parameter in this portion, and is not always the same as the wavelength λg in other stripline portions.

[0011]

BEST MODE FOR CARRYING OUT THE INVENTION The non-contact type coupling circuit of the present invention is arranged in front of each antenna element of an Aire antenna, so that the phase of a feed signal of an array antenna can be continuously changed, and an onlay is provided. The direction of the main lobe of radiation from the antenna can be changed continuously.

[0012]

FIG. 1 is a partially cutaway perspective view of a preferred embodiment of a non-contact type coupling circuit according to the present invention, and FIG.
FIG. 3 is a cross-sectional view taken along the line A, and FIG. 3 is a top view of the rotary coupling conductor and the output-side strip line in FIG.

A lower surface of a dielectric substrate 1 made of an electrically insulating material such as glass fluorine resin or alumina is covered with a conductive film 2 made of a conductive material such as copper.

On the upper surface of the dielectric substrate 1, a linear input-side stripline 3 and an arc-shaped output-side stripline 4 are formed.

An input terminal 3a is provided at one end of the input strip line 3, and output terminals 4a and 4b are provided at both ends of the output strip line 4.

At the other end of the input-side strip line 3, an input-side strip line coupling portion 3b is provided, and the output-side strip line 4 is formed in an arc shape centered on this.

The entire upper surface of the dielectric substrate 1, the input side strip line 3, and the output side strip line 4 has a thickness of 0.2.
It is coated with an insulator thin film of about mm. In FIG. 1, the dielectric substrate 1 and the insulating thin film 5 are partially cut away for easy understanding.

A rotation coupling conductor 6 is rotatably provided on the insulating thin film 5. The rotation axis and the like of the rotation coupling conductor 6 are as follows.
It has been omitted for clarity. The direction of rotation is indicated by arrow F.

The rotary coupling conductor 6 has an input-side coupling section 6a at a portion corresponding to the input-side stripline coupling section 3b of the input-side stripline 3, and an output-side coupling section 6b at an end of the output-side stripline 4. Have.

When the wavelength of the operating frequency on the rotation coupling conductor 6 is λg, the rotation coupling member 6 is connected to the output side coupling portion 6b.
The part of which width becomes almost circular at the position of λg / 4 from
c.

The section from the output side coupling portion 6b to the portion 6c having a substantially circular width is a load impedance circuit 6d of the present invention.

When the characteristic impedance of the output side strip line 4 is Z _OUT , the output side strip line 4 is branched into two circuits at the output side coupling portion 6b. , The load impedance becomes approximately Z _OUT / 2.

The characteristic impedance of the input side of the rotary coupling conductor 6 is defined as Z _IN . Because it is usually _{Z OU T = Z IN = 50Ω} , not is consistent in this state. In the present invention, impedance is converted and matched by a quarter-wave λ transformer comprising a load impedance circuit of the rotary coupling conductor 6.

Assuming that the capacitance of the load impedance circuit portion is C and the group velocity of the signal is v _P , the equivalent characteristic impedance Z _O of this portion is expressed as Z _O = (v _P C) ⁻¹ and the output is The impedance matching condition in the side coupling portion 6b is Z _IN · Z _OUT = Z _O ² .

As shown in FIGS. 1 and 3, the rotary coupling conductor 6 is provided with a circularly widened portion 6c in the load impedance circuit portion to increase the capacitance C,
The matching condition is satisfied by reducing the equivalent impedance Z _O.

As is apparent from the above description, the shape of the load impedance circuit is not limited to those shown in FIGS. 1 and 3, and by increasing the width of the line in this portion, etc. It can also be realized by adjusting the capacitance C.

In the non-contact type coupling circuit according to the present invention, since the matching is performed by the load impedance circuit, the output side coupling portion 6b has the width of the output side strip line 4 or the width of the output side strip line 4 in order to prevent loss at the peripheral portion. It is enough to make it slightly larger, and it can be made smaller than λg / 4, so that given the size of the arc-shaped output-side stripline 4, the rotatable range of the rotary coupling conductor 6 is wide. This means that the range in which the phase of the signal can be varied is large.

[0028] Figure 4 shows an example return loss characteristic diagram of the non-contact type coupling circuit of Figure 1, 2, 3, f _o in FIG. 4 is a frequency corresponding to the lambda] g / 4 of FIG. In the band of 21%, -14 dB (standing wave ratio of 1.5) is obtained.

FIG. 5 is a graph showing the passage loss characteristics of the same non-contact type coupling circuit as in FIG. 4, and the values appearing at both output terminals 4a and 4b are the same.

[0030]

【The invention's effect】

(1) Power is equally distributed to both output terminals. (2) The phases of both output terminals can be complementarily and continuously varied. (3) Therefore, by using it as a feeder for each antenna element of the array antenna, the direction of the main beam of radiation from the array antenna can be continuously changed. (4) Since the two-way distributor and the phase shifter can be integrated, the structure is simple and the cost can be reduced. (5) Since there is no mechanical contact, noise generation and intermodulation problems can be solved. (6) Since the rotatable range of the rotation coupling conductor can be widened,
The range in which the phase of the signal can be varied is large.

[Brief description of the drawings]

FIG. 1 is a partially cutaway perspective view of a preferred embodiment of a non-contact type coupling circuit according to the present invention.

FIG. 2 is a sectional view taken along line AA of FIG.

FIG. 3 is a top view of the rotation coupling conductor and the output-side strip line of FIG. 1;

FIG. 4 is a return loss characteristic diagram of an example of the non-contact type coupling circuit of FIGS. 1, 2, and 3;

FIG. 5 is a graph showing the passage loss characteristics of the same non-contact type coupling circuit as in FIG. 4;

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Dielectric substrate 2 Conductive film 3 Input side strip line 3a Input terminal 3b Input side strip line coupling part 4 Output side strip line 4a, 4b Output terminal 5 Insulator thin film 6 Rotation coupling conductor 6a Input side coupling part 6b Output side coupling part 6c Wide part 6d Load impedance circuit

Continuation of the front page (72) Inventor Yuko Saito 3-3-1 Marunouchi, Chiyoda-ku, Tokyo Inside Electric Co., Ltd. (72) Inventor Masayoshi Serizawa 3-3-1 Marunouchi, Chiyoda-ku, Tokyo Inside Electric Co., Ltd. (72) Inventor Hirokazu Tsunoda 3-3-1 Marunouchi, Chiyoda-ku, Tokyo Inside Electric Power Industry Co., Ltd. (72) Inventor Yoshio Ebine 2-10-1 Toranomon, Minato-ku, Tokyo NTT Mobile Communications Network (56) References JP-A-6-326501 (JP, A) JP-A-9-214211 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) H01P 1/10 -1/195 H01P 5/12 H03H 7/20

Claims (2)

(57) [Claims] 1. A dielectric substrate, a conductor film covering a lower surface of the dielectric substrate, an input-side stripline provided on an upper surface of the dielectric substrate and having an input terminal at one end, and A rotatable coupling conductor rotatable about the other end of the input stripline and having one end coupled to the input stripline via an insulator, and an arc-shaped conductor centered at the other end of the input stripline. A non-contact type coupling circuit having an output terminal at each end and an output side strip line coupled to the other end of the rotary coupling conductor via an insulator.
When the lambda] g wavelengths in the rotary coupling conductor, the position of the lambda] g / 4 from the other end which is coupled with the output side strip line of the rotary coupling conductor, the width of the rotating coupling conductor
A load impedance circuit is provided in a section from the wide portion to the other end, a characteristic impedance from the one end of the rotary coupling conductor to the load impedance circuit is Z _IN , and a load impedance circuit of the load impedance circuit is provided. Assuming that the equivalent characteristic impedance is Z ₀ , and the impedance when the output side strip line is viewed from the load impedance is Z _L , Z _{0 is} approximately Z _IN Z _L
= Non-contact type coupling circuit characterized by satisfying the relationship of Z ₀ ² . 2. The wide width formed on the rotation coupling conductor.
2. The non-contact type coupling circuit according to claim 1, wherein the portion is a circularly wide portion .