JPH0818311A - Nrd guide distributing coupler - Google Patents

Abstract

PURPOSE:To provide the NRD guide distributing coupler which is small-sized and has a wide transmission frequency band width and improves the installation precision of mutual positions of lines and is ease to adjust and produce. CONSTITUTION:A branch line 5' having arbitrary length is provided at right angles to a main line 2, and branch line width b is made narrower than main line width (b) to bring about the operation mode conversion in lines. Both lines are closely brought into contact with each other or formed into one body at the intersection in a part extending over length (d) shorter than half of main line width.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention is a T-shaped branch line or an L-shaped broken line branch line composed of an NRD guide, in which the main line end portion and a part of the branch line end portion are closely contacted at right angles. The main line side LSM-branch line side LSE has a structure for mode conversion, which is smaller than the conventional one, the transmission frequency bandwidth is widened, and since the main line and the branch line are orthogonal to each other, the mutual position installation accuracy of each line is improved, The present invention relates to an NRD guide distributor / combiner in which adjustment of coupling amount and frequency adjustment can be quantitatively set and assembly reproducibility is improved.

[0002]

2. Description of the Related Art FIG. 11 is a diagram showing a basic structure of an NRD guide. In the figure, 1 is the upper and lower conductor plates, 2 is the dielectric line (height a, width b), and a is less than half the wavelength of the signal frequency in free space (for example, the spatial wavelength of 60 GHz is 5 mm, so there is a gap between the conductor plates). A is 2.5 mm or less). FIG. 12 is a diagram showing the unnecessary mode suppressor 4, in which the choke pattern 3 made of a conductor is arranged in the dielectric line 2 in the signal transmission direction, and the main mode is LSM (Longitudinal Section Magne) because of its low loss in the NRD guide.
modes other than tic mode, such as LSE (Longitudinal Se
(ction electric) mode, TEM mode, TE mode, etc. are suppressed. As an example of the LSM mode, the LSM ₀₁ mode which is the lowest order mode will be described.
As shown in (a), in a cross section perpendicular to the transmission direction of the dielectric line, a magnetic field is generated vertically to the upper and lower conductor plates, and an electric field is generated in parallel to the upper and lower conductor plates. Further, as an example of the LSE mode, the LSE ₀₁ mode which is the lowest order mode will be described. As shown in FIG. 13B, an electric field is generated vertically in the upper and lower conductor plates in a cross section perpendicular to the dielectric line,
This is a mode in which a magnetic field is generated parallel to the upper and lower conductor plates. N
In the RD guide line, different cutoff frequencies exist for the LSM mode and the LSE mode, and generally, if the line width b is made smaller, the cutoff frequency becomes higher, but the cutoff frequency in the LSM mode is higher than the cutoff frequency in the LSE mode. Indicates a value. Therefore, by adjusting the line width b (for example, when using a dielectric line having a signal frequency of 60 GHz and a dielectric constant εr≈2, if the line width is 2.5 mm, both LSM mode and LSE mode are transmitted, Track width 1.5m
When m is set, only the LSE mode is transmitted.) It is possible to realize a line that transmits only the LSE mode.

A conventional distributor / combiner composed of an NRD guide is, for example, one shown in FIGS. FIG. 14A shows a conventional T-shaped branch (hereinafter abbreviated as T-branch) or an L-shaped broken line branch (hereinafter abbreviated as L-branch) 2
An example of a distribution (equal distribution) distribution coupler is shown in FIG.
Shows an example of a three-way distribution coupler. In the example shown in FIG. 14, with respect to the main line 2 (width b) and the unnecessary mode suppressor 4, the branch line 5 (width b ′ and b ′ <b) is at right angles to each other as shown in the figure. It is arranged. It should be noted that the unnecessary mode suppressor 4 is not necessarily required at each end. The main line 2 or the unwanted mode suppressor 4 and the branch line 5 are in contact with each other only at the corners of the line ends, or there is a slight gap therebetween, so that they are electromagnetically coupled. In the example shown in FIG. 15A, the straight main lines 2 and 18
The structure is such that the 0 degree bend 6 and the 0 degree bend 6 are arranged at an interval g ₁ , and since only one of the lines used is a bend, it is called an asymmetric type. FIG.
In the example shown in FIG. 5 (b), two bends 6 ′ and 6 ″ are arranged at intervals g.
_The structure is such that the _two are opposed to each other, and is called a symmetric type. In both of the above, the degree of bonding is adjusted by adjusting the gap g ₁ or g ₂ . However, in the case of the conventional distributed coupler using the NRD guide as described above, in the case of the example shown in FIG. 14, the main line 2 or the unnecessary mode suppressor 4 and the branch line 5 are in contact with each other only at the corners at most. Since they are arranged almost independently, it is extremely troublesome to assemble and adjust the entire circuit. In addition, since the structure shown in FIG. 16 (a) is basic and the signal passes through the branch line 5 which is once a place, only a specific frequency determined by the width b ′ and the length L of the branch line 5 is used. The transmission line characteristic is extremely narrow due to the resonance type line structure in which is transmitted in a narrow band pass type. For example, the ratio band is only about 6%. In addition, FIG.
In the example shown in (b), the LS is made at the three points a, b, and c in the figure.
Designed to be M mode (If you try to use only LSM mode at a specific point of bend, the radius of curvature will be a specific point (angle)
Therefore, the radius of curvature R is usually R ≧ 5 in order to select a discrete value corresponding to the position and the transmission signal frequency.
It becomes as large as 10b, which is a factor that greatly hinders the miniaturization of the circuit, and when it is used in combination with other circuit elements, the location and the configuration are restricted. Further, since a bend is used, it suffices if the gap g ₁ or g ₂ can be set so that the points B are well opposed to each other as shown in the figure, but if they are arranged so that they are slightly displaced from the points B and face the opposing line. There is also a drawback that ripple due to unnecessary mode rises significantly in the passage characteristic and loss increases, so the bend installation position,
The circuit characteristics are largely limited by the inclination accuracy. In addition, since this type of coupler operates as if it were coupled at approximately one point of the bend, point B, the coupling bandwidth is extremely narrow, as shown in FIG. Only the characteristics of coupling only at the frequency can be obtained (ratio of 0.
1% or less). In the drawings of the above NRD guides, the upper and lower conductor plates are not shown for simplification.

[0004]

SUMMARY OF THE INVENTION The present invention solves the various problems associated with the conventional NRD guide distribution coupler as described above, makes it possible to downsize the entire circuit, widens the transmission frequency bandwidth, and It is easy to improve mutual position adjustment of lines and installation accuracy, and it is possible to quantitatively set coupling amount adjustment and frequency adjustment, and assembly reproducibility is improved.
It is an object to provide a D-guide distribution coupler.

[0005]

In order to solve the above-mentioned problems, in the present invention, in a T-branch NRD guide distribution coupler composed of an NRD guide, the main line is in the LSM mode which is the main mode of the NRD guide. The branch line is mainly composed of lines that operate in the LSE mode, which is a sub mode, and the end of the branch line is the main line when the width of the main line is b at a point where the branch line and the main line are orthogonal to each other. A structure in which a finite length portion (not 0) having a length of b / 2 or less at the end portion is closely contacted at right angles or a branch line end portion is closely contacted at right angle with the side surface of the main line, or the main line is preliminarily set in the above state. In the L-branching NRD guide distribution coupler composed of the NRD guide, the main line operates in the LSM mode which is the main mode of the NRD guide, and the branch line is LS When the width of the main line is b at a point where the branch line and the main line are orthogonal to each other, the branch line end is less than b / 2 of the main line end. It has a structure in which it is in close contact with a finite length portion (not 0) of the length at a right angle, or has a structure in which the main line and the branch line are integrated in advance in the above state, and the branch line and the main line are orthogonal to each other. At the point where the branch line end is actually closely attached to or integrated with the main line end, even if the length is b / 2 or more, it is b / 2 or less if calculated by the volume average of the branch line. I decided to design it so that.

[0006]

The conventional L shown in FIG. 16 (a) (in the figure, 2 is the main line, 4 is the unnecessary mode suppressor, and 5 is the branch line).
For branching, whether the main line 2 and the branch line 5 contact at only the corner,
Alternatively, the branch line 5 has a slightly separated structure, and the resonance effect is greatly affected by the branch line 5. Therefore, although the pass loss is reduced by resonance, the pass frequency band is extremely narrow. On the other hand, the L branch according to the present invention is shown in FIG.
As shown in (b). FIG. 16 shows that the constituent elements are the main line 2, the unnecessary mode suppressor 4, and the branch line 5 ′.
This is the same as the conventional case shown in (a). The unnecessary mode suppressor 4 does not necessarily have to be installed at the end of each main line. In the L branch according to the present invention, the branch line 5 '
At least one of both ends of the above has no certain gap between the main line 2 or the unnecessary mode suppressor 4 connected to the main line, and has a length d which is not 0 (when the width of the main line is b ≦ d ≦ d The feature is that the structure is such that the line is not interrupted by closely adhering at a position of (b / 2 is preferable). This structure is hereinafter referred to as a line coupling type. According to this structure, since the signal is continuously transmitted along the line, the circuit characteristic is not restricted by the length L of the branch line as in the conventional case shown in FIG. That is, the branch line length L ′ of the L-branch according to the present invention shown in FIG. 16 (b) is different from the above-mentioned conventional case in that it can be set to an arbitrary length. However, when the length is short, L'≈n / 2 · λ _g (n: 1
˜3, λ _g : wavelength in line at operating frequency) is easy to use. Further, the width b ′ of the branch line is a width in which the LSE mode of the used frequency is mainly in the branch line and the LSM mode is reduced (if the line width is reduced as described above, the LS is reduced).
(The M-mode cut-off frequency becomes higher than the LSE-mode cut-off frequency, and only the LSE mode can exist in the branch line.) For example, the width b of the main line is preferably in the range of b ′ ≦ 0.6b. The same effect can be expected when the end face of the branch line 5 ′ is brought into close contact with the side face of the main line 2 shown in FIG. 16 (d). In addition, FIG. 16C shows the above concept based on the T branch,
It is a Y-shaped branch circuit (hereinafter abbreviated as Y-branch) used at the same time for L-branching. In addition, in the structure of FIG.
The transmission power (port output) to the branch side is smaller than that of the structure of (c). Note that FIG. 3B is the same as FIG.
The state of the main line 2 according to the present invention shown in (b), the unnecessary wave mode suppressor 4 and the branch line 5'is shown in a state of being orthogonal to each other. Thus, the end portion b of the main line (unnecessary mode suppressor) is indicated by b. Instead of adhering the branch line closely to the location of / 2, the volume average of the ends of the branch line as shown in FIGS. 3 (a), (c), and (d) results in b / 2 or less. It may be designed as. 3 (e) shows the L branch line portion,
An example is shown in which the line portions are not separately formed and combined, but are integrally formed in advance.

In a usual microwave or millimeter wave circuit, for example, a rectangular waveguide directional coupler shown in FIG.
In the example of the dielectric substrate (back side ground) microstrip line directional coupler shown in FIG. 8 (b), T branch, Y branch, L branch
The transmission electromagnetic field mode in each branch path is T
Either E or TM, which is the quasi-TEM mode only in the microstrip line, is extremely rare to be converted into another mode for transmission. Therefore, the NR according to the present invention
The T-branch and the L-branch, which are the basis of the D-guide distribution coupler, including the conventional type shown in FIG. 16 (a), are all the main mode LSMs in the main line, but LSE (or LS) in the branch line.
The difference is that it is converted into E and LSM mixed mode and transmitted. Therefore, it can be said that each circuit according to the present invention essentially has a transmission bandwidth determined by the line width b ′ (or b ″) of the branch path. LSM, LS
Looking at FIG. 13 showing the E mode, L shown in FIG.
When the SM mode is cut out on the yz plane, FIG.
It can be seen that the electromagnetic field distribution is the same as the LSE mode shown in (b). FIG. 17 shows the pass characteristic of the equal distribution circuit.
The horizontal axis represents frequency, and the vertical axis represents pass loss when passing from the main line to the branch line. In the case of the present invention, the transmission band is, for example, as shown in FIG. %, Which is more than twice the transmission bandwidth of 6% of the conventional example shown in FIG. 17A.

[0008]

FIG. 1 is a first embodiment of the present invention, which is an example in which T-branch and L-branch are arranged in a Y-branch type. FIG. 1A shows an example in which signal power is distributed from port to port, which is 2/3 to ports and 1/3 to ports. This is because the straightness of the signal is strong and the power of the port is increased accordingly. In FIG. 1B, conversely, the case of inputting from the port, and in this case, the ports and the ports have an equal positional relationship, and the power is distributed to ½ of each other. FIG.
1C is an application example of FIG. 1A, in which the end face of the branch line is in close contact with the side face of the main line (in the middle, not at the end), and the input from the port is 2/3 of the port, 1 /
3 is output.

FIG. 2 is a second embodiment of the present invention, showing an example of equal distribution and equal distribution. In the example of the two equal distributions shown in FIG. 2A, as shown in the drawing, the contact portion between the branch path and the main line is d ₁
Broadband performance is realized by setting ≈b / 3 and d ₂ ≤b / 2. In the example of three equal distribution shown in FIG. 2B, the characteristic that the ports of the main line and the other lines are not in close contact with each other is equally distributed. It is needless to say that the other end of the branch line is in close contact with the end of the main line at the branch destination with d ≦ b / 2. With such a structure, the wide band characteristic as shown in FIG. 17B is realized in the example of the equal distribution shown in FIG.
It should be noted that FIG. 17A shows the conventional 2 shown in FIG.
It is a frequency characteristic of an equal distribution circuit. FIG. 4 is a diagram of a third embodiment of the present invention, showing an embodiment of an irregular two-divided path according to the present invention.

FIG. 5 shows a fourth embodiment in which an I-shaped circuit is constructed by using a plurality of T branches according to the present invention.
5 (a) and 5 (b) are an example of a single well portion,
(A) is an example in which there is no unnecessary mode suppressor in the main line in the square shape, (b) is an example in which there is an unnecessary mode suppressor, (c)
Shows the case of two well-shaped cases.
The operation of each circuit shown in FIG. 5 is such that the signal input to the port is appropriately distributed to the ports ,. However, if the line lengths L ₁ , L ₂ and L ₃ are designed to have specific values, the so-called T-type ,
A π-type filter can be configured, and the distributor has a filter effect. In addition, the branch path length L ₁ is L ₁ = (2n−1) λ _E
/ 4 (λ _E : wavelength in line of main mode in branch path, n: positive integer), L-shaped main line length L ₂ (and L ₃ ) is L ₂ = (2m−
1) λ _M / 4 (L ₃ = (2m-1) λ _M / 4) or L ₂ =
mλ _M / 2 (L ₃ = mλ _M / 2) (λ _M : wavelength of main mode in main line, in-line wavelength of main mode, m: positive integer). HYB with 90 ° phase difference between terminals and ports
A mold directional coupler could be realized. Therefore, according to the present embodiment, the frequency band is the conventional example NR shown in FIG.
D It is sufficiently wider than the directional coupler using the inter-guideline coupling, and it is based on a right-angled structure, and since the right-angled branch paths are in contact with each other, positioning and dimensional accuracy are easy to obtain, and a small directional coupler can be realized. .

FIGS. 6A, 6B and 6C all show a fifth embodiment of the coupler realized by arranging another line in parallel with the side surface of the branch path. Since they are spatially coupled, a 90-degree phase difference will be obtained. In the coupler shown in FIG. 6, the center frequency to be mainly coupled is determined by the branch path length L.

FIG. 7 shows a sixth embodiment of the present invention.
7A is an example of a spatial combiner for T-branch application, and FIG. 7B is another embodiment of the configuration of FIG. 7A.

FIG. 8 is a diagram showing a seventh embodiment of the present invention. FIG.
(A) is an embodiment of a coupler that spatially couples on both sides of a branch path, and an input signal from a port is divided into two parts, which are filtered by gaps H, I and line overlapping lengths L ₁ , L _2. It becomes a coupler with an effect. FIG. 8B is an example in which the gap J and the line overlapping length L are provided on the main line side.

FIG. 9 shows an eighth embodiment of the present invention. Figure 9
(A) shows an embodiment of a balanced mixer having a square-shaped circuit as an application example of the directional coupler of the present invention. Track length L
Distributing directionality is created by using the dimensional rules for L ₁ and L ₂ described with reference to FIG. Here, in the pattern substrate 7 used for extracting the IF output (f _IF ), as shown in FIG. 9B, the RF choke pattern 9 is formed on one surface of the dielectric thin plate 8, and the K and M portions contacting the port are formed. Each pattern electrode is loaded with a diode 10. When RF (f _RF ) is input from the port and LO (local f _LO ) is input from the port, RF and LO are simultaneously input to the port, but the phase difference is 90 °, and this circuit operates as a balanced mixer. It will be.

FIG. 10 shows an example of a conventional balanced mixer using the conventional distributor / combiner shown in FIG. In this example, unlike the above-described eighth embodiment of the present invention, the coupling portion between the main line and the branch line is in contact with each other at a corner or is slightly apart. Therefore, the coupling between the main line and the branch path is not as strong as in the above embodiment.

FIG. 19 is a diagram showing an example of a conventional balanced mixer using a bend coupler, (a) is a balanced mixer using an asymmetric bend coupler (directional coupler), and (b) is symmetric. Type bend coupler (directional coupler)
A balanced mixer using is shown. In this type of conventional balanced hand mixer, two diode mounting boards are connected and used, but in this example, one diode mounting board is used for supplementation, and the IF signal is transmitted on the same plane. Therefore, there is an effect that the transmission loss is also reduced.

[0017]

EFFECTS OF THE INVENTION A main line and a part of a branch line orthogonal to the main line are in close contact with each other, and a line coupling type branch structure based on a T branch or an L branch is provided, and an orthogonal branch point of an NRD guide,
Since it is a mode conversion structure between the main line and the branch line, it can be downsized, the transmission frequency bandwidth is widened, the mutual position of each line and the installation accuracy are improved, and the coupling amount adjustment and frequency adjustment can be set quantitatively. As a result, assembly reproducibility is improved.

[Brief description of drawings]

FIG. 1 is a diagram of a first embodiment of the present invention.

FIG. 2 is a diagram illustrating a second embodiment of the present invention.

FIG. 3 is a schematic cross-sectional view of a main portion of a main line end according to the present invention. It is a figure which shows the example made longer than the half of the width of a track | line.

FIG. 4 is a diagram of a third embodiment of the present invention.

FIG. 5 is a diagram of a fourth embodiment of the present invention.

FIG. 6 is a diagram of a fifth embodiment of the present invention.

FIG. 7 is a diagram of a sixth embodiment of the present invention.

FIG. 8 is a diagram of a seventh embodiment of the present invention.

FIG. 9 is a diagram of an eighth embodiment of the present invention.

FIG. 10 is a diagram showing an example of a balanced mixer using a conventional distributor / combiner.

FIG. 11 is a diagram showing a basic configuration of an NRD guide.

FIG. 12 is a diagram for explaining an unnecessary mode suppressor provided in the signal transmission direction on the main line of the NRD guide.

FIG. 13 is a diagram for explaining an LSM mode and an LSE mode which occur in the line of the NRD guide.

FIG. 14 is a diagram showing an example of a conventional distribution coupler for 2-division distribution and 3-division distribution using T-branch and L-branch.

FIG. 15 is a diagram showing an example of a conventional distributor / coupler constructed by using a bend of an NRD guide.

FIG. 16 is a diagram showing a comparison between the L branch of the conventional NRD guide and the L branch and Y branch of the NRD guide according to the present invention.

FIG. 17 is a diagram showing a comparison of the frequency band characteristics of the L branch of the conventional NRD guide and the L branch of the NRD guide of the present invention.

FIG. 18 is a diagram showing an example of a rectangular waveguide directional coupler or a microstrip line directional coupler used in a conventional microwave or millimeter wave circuit.

FIG. 19 is an example diagram of a conventional balanced mixer using a conventional bend-type coupler (directional coupler);
Shows a balanced mixer using an asymmetric bend coupler (directional coupler), and (b) shows a balanced mixer using a symmetrical bend coupler (directional coupler).

[Explanation of symbols]

1 ... Upper and lower conductor plates of NRD guide 2 ... Main line made of dielectric 3 ... Choke pattern 4 ... Unwanted mode suppressor 5, 5 '... Branch line 6 ... Bend 7 ... Pattern substrate 8 ... Dielectric thin plate 9 ... RF choke pattern 10 ... Diode 11 ... High permittivity thin plate

Claims (6)

[Claims] 1. An NRD for a T-shaped branch line, which is composed of a dielectric line for signal transmission and an NRD guide composed of upper and lower conductor plates sandwiching the dielectric line at intervals less than half of a free space wavelength of a signal frequency.
In the guide distribution coupler, the main line operates in the LSM mode which is the main mode of the NRD guide, the branch line operates mainly in the LSE mode which is the sub mode, and the LSM operates at the branch point.
-Where the branch line and the main line are orthogonal to each other when configured to perform LSE mode conversion, and when the width of the main line is b, at least one of both ends of the branch line is in close contact with the end of the main line at a right angle. There is always a finite length location and the length of the close contact part is b / 2 or less, or at least one of both ends of the branch line is in close contact with the side surface of the main line at a right angle, or in the above-mentioned state the main line An NRD guide distribution coupler having a structure in which a branch line and a branch line are integrally formed in advance. 2. An N-shaped bent line branch line composed of an NRD guide composed of a dielectric line for signal transmission and an upper and lower conductive plates sandwiching the dielectric line at intervals less than half of the free space wavelength of the signal frequency.
In the RD guide distribution coupler, the main line operates in the LSM mode which is the main mode of the NRD guide, and the branch line is L
It operates in either SE mode or LSM mode and is configured to perform LSM-LSE mode conversion at a branch point, and at a point where the branch line and the main line are orthogonal to each other, when the width of the main line is b, At least one of them has a finite length part that is in close contact with the end of the main line at a right angle, and the length of the close contact part is b / 2 or less, or branched to the main line in the above-mentioned state in advance. An NRD guide distribution coupler having a structure in which lines are integrally formed. 3. The branch line and the main line are orthogonal to each other, and the length of the main line end where the end of the branch line is actually adhered or integrally formed is b / 2 or more, but the volume of the branch line is large. 3. The NRD guide distributor / combiner according to claim 1, wherein the NRD guide distributor / combiner is designed so as to have an average value of b / 2 or less. 4. A T-shaped branch line or an L-shaped broken line branch line composed of an NRD guide is mainly used for distribution and combination of signals or electric power.
4. The NRD guide distribution coupler according to any one of 3 to 3. 5. A distribution combiner, a filter, or a directional coupler is formed by combining T-shaped branch lines composed of a plurality of sets of NRD guides in a square shape. 3. The NRD guide distribution coupler according to 3. 6. A coupler circuit or a filter circuit is constituted by lines installed in parallel at regular intervals on a side surface of a branch line branched from a main line. NRD guide distribution coupler.