JPH07105654B2 - IC-based magic T using deformable coupling slot line - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial field of application] The present invention relates to a magic T in the form of a microwave IC.

[Conventional technology]

Several Magic Ts that have been converted to microwave ICs have been proposed in the past. FIG. 4 shows an example of a magic T using a coupling slot line, 2 is a coupling slot line on the surface of the substrate, 1 is the other end of a 1/4 wavelength slot line connected to the coupling slot line 2 at one end. A quarter-wavelength slot line on the front surface of the substrate formed by connecting them to each other, H is a first input / output terminal provided on the microstrip 11 on the back surface of the substrate which is coupled orthogonally to the connection point, and E is a coupling slot line 2 The second input / output terminals P ₁ and P ₂ provided on the microstrip 12 on the back surface of the substrate that are orthogonally coupled to the connection portion of the 1/4 wavelength slot line 1 and Third and fourth input / output terminals provided on the microstrip line 13 formed on the back surface of the substrate so as to be orthogonal thereto, 8 and 9 are front-back short-circuit conductors, and 10 is for increasing the impedance of the junction slot line 2. Beyond A cavity provided in (see Japanese Patent Application No. Sho 52-92762). It is well known that the 1/4 wavelength portion may be an odd multiple thereof (the same applies to the following description).

FIG. 2a is a plan view showing a state of electric fields excited by the slot lines 1 and 2 when the magic T is fed from the input / output terminal H, and FIG. 2b is a microstrip 12 at that time.
2c shows the state of the excitation electric field in the thickness direction of the portion, and FIG. 2c shows the state of the excitation electric field of the portion of the microstrip 13. The electromagnetic wave input from the microstrip on the back side is transmitted to the right by the short-circuit conductor 8 over the slot lines 1 and 2 on the front side by an electric field as shown in FIG. 2a. At the terminal E part,
As shown in FIG. 2b, the electric field is directed in the opposite direction above and along the thickness direction of the slot line 2, so that the slot line 2 and the microstrip 12 on the back surface are short-circuited at high frequency, and the microstrip 12 is located above the slot line 2. Slot line 2 because it is opened with length λ / 4 (or an odd multiple of it)
When viewed from the center of the, the electromagnetic waves are not excited in the microstrip 12, and no output is generated from the input / output terminal E. Further, in the portion of the microstrip 13, as shown in FIG. 2c, since the electric field is directed in the same direction in the thickness direction due to the presence of the short-circuit conductor 9, P ₁ and P ₂ output in phase. The excitation mode shown in Fig. 2a is called the odd mode.

The state of the electric field similar to the above when electric power is supplied from the input / output terminal E is shown in FIGS. 3a, 3b and 3c. FIG. 3a is a plan view. Since electric power is supplied from the terminal E, the electric field is directed upward in the drawing above the slot lines 1 and 2, and the electric field is gradually directed in the arc-shaped portion of the left slot line. , The direction of the microstrip 11 from the terminal H is reversed. Therefore, the short-circuit conductor 8 is short-circuited at a high frequency and is not output from the terminal H. Meanwhile, in the portion of the microstrip 13 is outputted to each other in opposite phases in the P _1, P ₂ the electric field on both sides of the short-circuit conductor 9 as the 3c view becomes reverse. This excitation mode is called an even mode.

[Problems to be solved by the invention]

As is apparent from the figure, such a magic T needs to make holes in the substrate for providing the front and back short-circuit conductors 8 and 9, which causes a large manufacturing error and deteriorates the balance. Since the impedance discontinuity is generated, the exchange characteristic of the line in the high frequency band is deteriorated.

[Means for solving problems]

The present invention proposes a microwave IC magic T utilizing the modified coupling slot line of FIG. 5a and the modified slot line of FIG. 5b in order to solve these drawbacks. To do.

〔Example〕

FIG. 1 shows an embodiment of the present invention. Reference numeral 21 denotes a modified slot line having a length of an odd multiple of 1/4 wavelength in which conductors are arranged in the drawing of a dielectric substrate. Shown in Figure 5b. The constituent conductors of a general slot line are arranged on the same surface, whereas the constituent conductors of this modified slot line are arranged on both surfaces of the dielectric substrate. The ends of both conductors form a gap or slot through the dielectric substrate and operate as a slot line. That is, both the normal slot line and the modified slot line 21 have the basic transmission mode.
TE mode, which is essentially the same type of transmission line. Reference numeral 22 denotes a modified coupling slot line, and the structure of this modified slot line is shown in FIG. 5a. In a general coupling slot line, the center conductor and the ground conductors on both sides are on the same plane, whereas the center conductor of the modified coupling slot line 22 is arranged on a plane different from the ground conductor. The transmission mode of this modified combined slot line 22 is essentially the same as the two orthogonal modes (even / odd mode) of the conventional combined slot line,
The structure of FIG. 5a also operates as a combined slot line. Reference numerals 23 and 25 denote microtostrip lines arranged so as to be orthogonal to the slot line 22. Here, the microstrip line 25 intersects at the connecting portion of the deformation slot line 21 and the deformation coupling slot line 22 on the extension of the microstrip line 26, but these conductors are electrically insulated from each other by an air bridge structure or the like. FIG. 1 shows a structure in which 26 conductors on the extension are crossed over by ribbon bonding. Needless to say, the vertical relationship between 25 and 26 may be reversed, and a connection method such as wire bonding may be used instead of ribbon bonding. 24 is a slot line coupled to the modified slot line 22 and having a length that is an odd multiple of 1/4 wavelength.

FIG. 6 shows the state of the excitation electric field when the magic T of the present invention is fed from the first input / output terminal H. The signal propagating through the microstrip 26 from the H terminal is branched in parallel to the 1/45 wavelength modification slot line 21, and is transmitted to the line 22 in the electric field state in the direction as shown in the figure. This is an odd mode propagation,
The same principle as in Fig. 2b shows that no output appears at terminal E, and
In-phase distribution is applied to terminals P ₁ and P _{2 according} to the same principle as in Fig. 2c.

FIG. 7 shows a case where electric power is supplied from the input / output terminal E, and since even mode propagation occurs on the modified coupling slot line 22, H
No output appears from the terminal, and reverse phase distribution is made to P ₁ and P ₂ .

The short-circuited slot line 24 shows the case of 1/4 wavelength in FIG. 1, and the impedance seen from the branch point where the microstrip line 23 intersects is theoretically infinite, and the cavity of FIG. It is provided for the same purpose as when 10 is provided. Generally, a quarter-wavelength slot line is advantageous because it is smaller than the cavity size. In addition, the slot line 24
Is theoretically infinite if the length is an odd multiple of 1/4 wavelength, so the length should be an odd multiple of 1/4 wavelength, especially when the design frequency is high. Is also possible.

〔The invention's effect〕

As described above, according to the present invention, it is possible to eliminate the substrate drilling process that causes the deterioration of the manufacturing accuracy, and therefore the following advantages can be obtained.

(1) The impedance characteristic and isolation characteristic of the magic T can be improved.

(2) Manufacturing can be simplified because there is no drilling process.

(3) Since there is little variation in manufacturing, it can be realized in a high frequency band higher than the X band.

[Brief description of drawings]

FIG. 1 is an embodiment of the present invention, and FIGS. 2a, 2b and 2c are excitation electric field diagrams when a conventional magic T is fed from the H terminal,
Figures 3a, 3b, and 3c are excitation electric field diagrams when a conventional magic T is fed from the E terminal, Fig. 4 is a block diagram of a conventional microwave magic T, and Fig. 5a is a modified coupling slot line. 5b is a cross-sectional view of the modified slot line, FIG.
FIG. 7 is an excitation electric field diagram when the magic T of the present invention is fed from the H terminal, and FIG. 7 is an excitation electric field diagram when the magic T of the present invention is fed from the E terminal. 1 …… 1/4 wavelength slot line, 2 …… Coupling slot line, 8,9 …… Short-sided conductor, 10 …… Slot line cavity, 11,12,13 …… Microstrip line, 21 …… 1 /
4 Deformed slot line, 22 …… Deformed coupled slot line, 23,25,26 …… Microstrip line, 24 …… 1 /
4-wavelength slot line.

Claims (1)

[Claims] 1. One end of a first modified coupling slot line in which a center conductor is disposed on one surface of a dielectric substrate and a ground conductor is disposed on the other surface, and a coupling slot line is formed via the dielectric substrate. , The conductors are arranged on both sides of the dielectric substrate, and two second modified slot lines having slot lines formed through the dielectric substrate are connected to each other with a length of an odd multiple of 1/4 wavelength, The other ends of the two second modified slot lines are connected to each other, and the first microstrip input / output terminal is connected to the connection point, and the first modified coupling slot line and the second modified slot line are connected. In the connection part, the first
The second microstrip input / output terminal whose tip is open at a length of an odd multiple of 1/4 wavelength from the center conductor of the modified coupling slot line is electrically connected to the center conductor of the first modified coupling slot line. Of the first deformable coupling slot line is branched into two microstrip lines to form third and fourth input / output terminals, An IC using a modified coupling slot line characterized in that a Stott line having an odd length of 1/4 wavelength is coupled to the branch point orthogonally to the microstrip line.
Magic T.