DE2023631A1 - Steaming transmission line - Google Patents

Description

ί ' i K NS KAlJ .. HACr-i ^l -'- ^{j ::} ' ° ^MC - '·

fvj fc.N i ,; '; ■ / ■ /.- '.τ

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28 / 4.70 P 15 908 YQ9-68-094

International Business Machines Corporation, Armonk, N ₀ Y ₀ 10504

D / ioipfende transfer line

The invention relates to an attenuating transmission line having a conductive base layer, a signal conductor and one in between located dielectric * With known attenuators, which are made of in T-or II-Fona held together resistance elements, reflection and dispersion is unavoidable * transmission lines of the type mentioned above, 'even if unintentionally under certain circumstances, a dampening effect "

To design object of the invention ie-t ee "a transmission line of the type mentioned eu, tHe thus a certain damping effect is e-rzfelbar namely wenigatene for a Sigaaldurchlaufrichtungc avoiding distortion and signal reflections The invention will be manufacturing technology easy to implement"

The invention is characterized in that the necessary Transverse and longitudinal resistance formed by sections of the conductor einrJ, in done * i by yourself over the whole length of the relevant

009885 / U26

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Section steadily increasing or decreasing values of the width of the signal conductor and / or the distance between the signal conductor and mass section, the total impedance of the section in question is distributed over the entire length of the section. In contrast to known dampers consisting of resistance elements, the characteristic impedance of damping transmission lines according to the invention is distributed over the relevant section and this distribution is carried out in such a way that distortions in both signal directions and reflections in one signal direction can be avoided in the desired manner. Compared to the known dampers, production is very simple because a transmission line according to the invention works in the same way as the known transmission line © !! can be produced, whereby the geometrical and material characteristics of the dielectric and the signal conductor only have to be introduced in the area of the damper.

A further development of the invention is characterized in that a separate section is provided for each of the individual transverse resistances and that the value of the characteristic impedance at the adjacent ends of two adjacent sections are the same »

A preferred embodiment of the invention is characterized by * net, that between two sections assigned to a longitudinal resistance and a transverse resistance, 1e a section with went over Section constant value for the width of the signal conductor and the Distance between the signal conductor and the Maseerasehicht provided is what value matches the value at the ends of both adjacent ones The longitudinal or transverse resistance of rearranged sections is the same.

The invention can be implemented with a constant distance between the ground layer and the signal conductor, in which the width of the signal conductor varies, but it can also be implemented at constant

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the width of the signal conductor by varying the distance «This both variations can be combined with each other.

The invention will now be explained in more detail with reference to the accompanying drawing. In the drawing shows:.

the electrical equivalent circuit diagram of a T-damper, the electrical equivalent circuit diagram of an if damper,

a diagram showing the course of the characteristic impedance over the length of the flowing transmission line for a T-damper shows

a corresponding diagram for an IL damper,

in cross section a transmission line as the invention is based,

! • 'ig, 6A the top view of a damping line piece of a Transmission line according to the invention,

63 shows the longitudinal section to FIG. 6A

7A shows a second exemplary embodiment according to the invention in a representation corresponding to that in Pig. 6A and

7B shows the longitudinal section of FIG. 7A.

Fig. 1 shows a known unbalanced T-damper with two in Series connected resistors IO and 12 and a cross resistor 14. The input impedance between the input terminals 17 is with Z ^ and the output inequality between the output terminals is marked with Zg «The resistors are like an equivalent circuit diagram lumped elements, but the circuit diagram is nevertheless characteristic of these dampers and for explaining the Invention valuable. The transmission system formed by the damper comprises measurement conductors 15 and transmission conductors 18, between which there is a dielectric. The geometrical configuration of elements 16 and 18 and that between them

0 09-885 / U 26

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The dielectric determines the characteristic impedances of the transmission line. It is assumed that the impedance Z ₁ = Z ₂ ⁰ 50 ohms and that the resistance value of the series resistors 10 and 12 is each 8.55 ohms and that the resistance value of the cross resistor 14 141 »9 Ohms and that the attenuator causes an attenuation of 3 db (decibels). If you use concentrated switching elements, then the Danish noise and also the distortion and the reflection are due to the discontinuities and parasitic reactances due to the concentrated resistances 10, 12 and H. the same, regardless of the direction in which a signal passes through the transmission line or the attenuator. The same is the case with an unbalanced fC transistor, as it is shown in Fig. 2 and in which two concentrated cross resistors 20 and 22 and a concentrated resistor connected in series are provided · The ground line is designated 26 and the transmission line 28 » It is again assumed that the characteristic impedance is 50 ohms ( _{i.e. the input impedance Z 1} and the output _{impedance Z 2} are 50 ohms each) that the two transverse resistors 20 and 22 each have a resistance of 292 ohms and that the resistance of the Series resistance 24 is 17.6 ohms and the attenuation is 3 dB (decibel). As with the attenuator according to FIG. 1, it is the case with the attenuator according to FIG , the distortion and the ReflektMon has due to the discontinuities and parasitic reactances. It should be emphasized once again that the input impedance Z ₁ , which is between the input connections 27, the output impedance Z ₂ , which is between the output connections 29 and not approximately the impedance which is between the connections 27 and 29.

009885/426
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ΥΟ9-68-Ο94

Pig. 3 shows a diagram for the T-Dänrofer. In Fig. 3 is on the The abscissa is the length of the transmission line and plotted on the Ordinate is the value of the characteristic impedance Z. Line 30 essentially shows the value of the characteristic impedance over the length of the demofer. The small fluctuations in sections 3OA and 3OB should not cause fluctuations in the impedance » show values, but only highlight these sections symbolically by drawing. These are the two sections that define the Series connected series resistances of the damper correspond. Of the Dashed section 300 below curve 30 denotes the Effective range of the transverse resistance. The three sections 30A, 30B and 300 of the drawing define four further sections 32A, 32B, 32C and 32D. In the latter four sections is the characteristic impedance constant. In * Sections -32A and 32D is the characteristic impedance Z = 50 ohms, while in in sections 32B and 320, the impedance Z has a minimum and a minimum, respectively assumes a maximum value. The sections 32B and 320 between the transverse resistance on the one hand and the two series resistance can be any length greater than zero. They are of no particular importance for the invention because sections 30A, 300 and 30B can follow one another directly. Sections 32B and 320 show the diagram in FIG Practice actual course of a damper according to Fig. 1,

According to FIG. 2, the damping is due to the two series resistances, which correspond to sections 30A and 30B and of the transverse resistance corresponding to section 300. If a signal passes through the damper in the direction of arrow G, that is, based on the figure from FIG left to right, then it will be attenuated without distortion and reflection. In the 3 db attenuator from FIG. 1, the sections 30A and 300 correspond to the resistance values 8.55 ohms and the section of the Cross resistance of resistance 141 »9 ohms. The relevant resistances are distributed over the entire length of the relevant

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cuts. The characteristic impedance falls evenly into the Sections' 50A and 30B and rises above section 300. This is why signals can be transmitted in one direction without distortion or reflection. It is coming externally because the end portions 32A and 32D both have the same characteristic impedance of 50 ohms. In the case of a transmission line, the geometric details of which are given in FIGS. 6A-6B and 7A and 7B, the series resistance is provided by a resistive section of the conductor strip and the cross ^ ideretand due to dielectric losses, that is so by a dielectric between the transmission conductor and the ground potential through which a certain current flow takes place can, educated »

According to FIG. 3, the characteristic impedance falls linearly in the region of the sections 30A and 30B. This linear drop is the optimum for a series resistance section, in which the introduced series resistance per unit length has a constant value over the entire length of the section. The length of the section and the drop in the characteristic impedance depend on the specific resistance of the resistor material used and can be changed so that the power loss can be distributed over sections of arbitrary length. The characteristic impedance increases in the cross-resistance portion 300 increasingly au, as shown in Fig. 3 is visible and that this is done © increase over the length for a hyperbola if the lateral resistance along the entire length of this section in d '@ r unit length a has a certain constant value.

In contrast to the damper according to FIG. 1, in which the characteristic Impedance between input and output connection 17 and 19 is not defined, in a damper according to the invention, the characteristic impedance is preferably substantially at each Spark between the input connections 37 and the Anegangeanlietts-

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sen 39 according to Fig. 3 defined

Sin damper with the öharafcteristika after Pig *. 3 is symmetrical in the sense that the attenuation is the same regardless of the direction in which a signal passes through the attenuator and that no distortion occurs _{that a signal which passes through 9} from left to right in relation to the figure is transmitted without se 'flections, while signals which rotate from right to left cause considerable reflections the direction, corresponds to an idealized case and the elimination of reflections in one direction is due to the use of sections in which the characteristic Impe dans siciij as shown, changed evenly. The use of distributed resistance elements also makes it possible to avoid parasitic reactances that occur when using concentrated resistance elements * This in turn requires attenuation without reducing the bandwidth or changing the frequency in any other way.

Fig. 4 corresponds to the diagram in Fig. 3 one after the other Invention manufactured Tf damper. In Pig «4 is the characteristic one Impedance; plotted by curve 40. Sections 40A and 40B correspond to the cross resistances and section 400 corresponds to the longitudinal iderstanä in between. This cons « end sections are separated by two sections 42B and 420, where the impedance is constant and has a maximum - respectively Has a minimum value · In the bite sections 42A and 42D in the end the impedance is constant 50 ohms «As in the example according to Fig. 2, according to Fig. 4, the total longitudinal resistance, which is distributed over the sections 400, 17.6 ohms and the entire Cross resistance distributed in each of sections 40A and 40B is, is 292 ohms «The attenuation is in this

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Case 3 db and there the characteristic impedance over the transverse resistance sections grows evenly and over that longitudinal resistance section drops evenly, there are no reflections and distortions for a signal direction from left to right.

The actual values of the characteristic impedance required for the transverse and longitudinal resistance sections can can be calculated as follows. For a longitudinal resistance section at where the distributed series resistance has a constant value per unit length the equation applies

Zv - Z / -. · »R ^ -A ·
.Λ U Ά.

It means:

Z _x is the characteristic impedance at the "distance from the beginning x» O of the series resistance section in relation to the intended signal flow direction;

Z ₀ is the characteristic impedance at the beginning of the section? R ^ is the constant value of the longitudinal resistance per unit of length χ is the length coordinate of a point over the entire section where X = O is the value at the beginning of the section and the value for χ increases positively from left to right.

For the transverse resistance section, the following applies if the transverse resistance value is constant per unit of length the relationship:

V-Y PV

¹ X ~ ¹ O " ^U K
where:

G _K is the constant transverse conductivity per unit length, which is reciprocal to the constant transverse resistance value όγο unit length;

Y ^ is the characteristic conductance at every point χ over the entire section related to the intended signal direction (with X = O at the beginning of the cross-resistance section)!

Y _n is the characteristic conductivity at the beginning of the Afo ~

8 5/1426
BAD OR) GINAt

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YO9-68-094 cut and

X. is as defined above

In practice it is possible to produce damper in which the Values for transverse and longitudinal resistance per unit of length are constant However, that is not the easiest manufacturing method in particular With regard to the transverse resistance · Therefore, the following is a general formula for determining the characteristic impedance the resistance at each point of the longitudinal resistance section specified «

Therein means;

Z ₀ qJ * rdx for x> 0

r = f (x) the resistance, in the unit of length, which is a variable Puncture from χ can be.

A corresponding one results for the cross resistance section Relationship in expressions of conductivity Y (= 1 / Z) s

Y _x «Y ₀ - o / ^x g dx for xt 0.

g * f (r) is the conductivity in relation to the unit of length that can be a variable function of χ

These equations assume that a transmission line the series resistance and the transverse conductivity in the normal sections of this line, so these are the sections 32A, 32B, 52C and 32D in FIG. 3 and 42A, 42B, 42C and 42D in FIG. 4 Is zero.

Figures 6A, βB, 7A and 7B show embodiments of a damping, the conductor strip according to the invention with characteristics according to FIG. According to FIG. 5, such a conductor strip consists of a mass layer 50, a signal conductor 52 and a separating dielectric 54 in between · FIGS. 6A and 6B show a section of a Top view and a cross section through a T-damper, which as Conductor tape is executed and in which the characteristic impe-

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can be achieved by changing the distance between the conductive base layer 50 and the signal conductor 52 along the longitudinal and transverse resistance cuts. The line is in sections corresponding to the sections from Pig. 3, which are designated by the same reference numerals 32A, 30A, 32B, 30B, 32G, 3OC, 32D and 3OD in FIGS. 6A and 6B. For the sections 32A, 32B, 32C and 32D with constant impedance, a good dielectric is used, for example the polystyrene, foamed polystyrene or the like known under the trade name Teflon - essentially an insulator as good as possible - purely the conductor is good in these sections electrical conductor material, for example copper, is used for the signal conductor 52. In the resistor sections 30A and 30B with distributed resistance, the dielectric may be the same, but the signal conductor 52 is then made of resistive material in these sections. a thin film of conductive material? which has the required resistance due to its small cross-section ₉ which is determined by the relationship R ³¹ S ¹ J *

In the transverse resistance section, the signal X conductor 52 is made of the same highly electrically conductive material as in the constant resistance sections, but the dielectric in these areas is one with dielectric losses ». The dielectric is arranged between the signal conductor and the conductive ground layer 50 and thus allows a certain current flow between these two conductors, which is a puncture of the frequency and is not a cross resistance between the signal conductor 52 and the measuring section 50 via the transverse resistance section 300 introduces "Bi®s © e lossy dielectric can consist of one material -" such as is used for the manufacture of resistors, for example.

The thickness of the dielectric 54 and thus the distance between ä, em Signal conductor 52 and ground not 50 falls over the XSngswider »

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Stand sections 3QA and 3OB from left to right. The signal conductor 52 has a constant resistance value per unit length over these sections 30A and 30B · The series resistance drops conditionally linearly due to the decreasing distance. Between the distance and there is no exact linear relationship to the series resistance, this is due to the fact that the characteristic impedance in the case of éiterbänäern this type does not have a linear puncture of the distance between signal conductors and ground layer underlies · In the transverse resistance section 300 the same dielectric is provided everywhere, namely a those with dielectric losses * The distance between the bulk layers and signal conductor takes over the section 320 from the left to the right to · The conductivity per unit length is therefore not constant · This fact leads in connection with the non-linear relationship between distance and characteristic impedance to a curve shape of the signal conductor 52 in the region of the section 300, as shown in Pig * 6B and that of the hyperbolic Contour differs from Fig. 3

In Fig. 7A and 7B, a second embodiment of a damping conductor strip is shown, in which again the individual sectors, which correspond to those of Fig. 3 are denoted by the same reference numerals as in Fig. 3. In this embodiment consists of the dielectric 54 and the signal conductor 53 in the individual Sections made of the same material as in the corresponding sections in the exemplary embodiment according to FIGS. 6A and 6B. The distance however, between the signal conductor 52 and the ground layer 50 is constant over the entire length of the damper. The width of the However, as shown in FIG. 7A, the signal conductor changes to to bring about the desired variations in the characteristic impedance in the sections 3OA, 3OB, 3OC · If the dielectric 54 Has constant properties over the entire length, then exists for the longitudinal resistance per unit of length in sections 30A and 30B there is no linear relationship and the transverse resistance per unit of length 1st in that. Transverse resistance section 300 not constant.

009885 / U26

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The desired relationship between the resistance per unit length is brought about in the example embodiment by changing the width of the signal conductor 52. In contrast to something In an enlarged representation from FIG. 7A, the edges of the sections 30A and 30B in order to achieve the resistance curve according to FIG. not exactly rectilinear and the bands of sections 30C to the hyperbolic To achieve resistance curve according to FIG. 3, not exactly hyperbolic.

Ausihrungsbeieiepiele according to the invention, which the characteristics according to Fig. 4 are based, are constructed accordingly, as the Embodiments according to FIGS. 6A, 6B, 7A and 7B with the exception that in a T-damper two transverse resistance sections are provided are, between which a 'longitudinal resistance section is located » In all these sections, the resistance, as in the exemplary embodiments according to FIG. and 7, distributed. The invention is not limited in its application to TT dampers and T-damper, the sections with distributed longitudinal and transverse resistance can also be combined in other ways, as is the case with series and transverse resistances of known dampers. The application of the invention is also not restricted to conduction bands according to FIG. 5; rather, it can also be used, for example on coaxial lines and other symmetrical or asymmetrical conductors with series and transverse resistances. It is essential that the Geometry of such a damping conductor according to the principles given above is set to the required impedance to be distributed over the relevant sections so that distortion and reflection, at least in one signal direction, are avoided. The application of the invention is not limited to symmetrical dampers, because in many cases the signal pass is only required in one direction, so that it is sufficient to have one each. Longitudinal and transverse resistance or a longitudinal or transverse section each to be provided «It is also possible to modify the

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examples through the appropriate selection of the resistor materials used and lossy dielectrics design the resistor sections so that the characteristic impedance am one end of the damper is different from the one at the other end of the damper

In a further modification of the illustrated embodiments, a section with distributed longitudinal resistance can also be combined with buckets of a section with distributed transverse resistance in a single section. By choosing appropriate materials, it is possible to achieve that the transverse resistance in this section increases while the longitudinal resistance decreases at the same time. The invention is preferred because it is particularly advantageous when implemented in connection with cables or liner strips whose conductors outside the special sections with distributed impedance as in the exemplary embodiments are plane-parallel conductor strips of the same width and the same spacing with a dielectric in between.

009885 / U26

Claims (8)

28.4.70 P 15 908 Υ09-68-094 EXPECTATIONS Attenuating transmission line with a conductive ground layer, a signal conductor and a dielectric located in between, characterized in that the necessary transverse and series resistances formed by sections (30A, 30B, 30G) of the conductor are in which by themselves over the whole length of the concerned Section steadily increasing or decreasing values of the width of the signal conductor (52) and / or the distance between the signal conductor (52) and ground layer (50) the total impedance of the respective Section distributed over the entire length of the section is. 2. Transmission line according to claim 1, characterized in that a separate section (30A ...) is provided for the individual transverse and series resistances and that the values of the characteristic Impedance at the adjacent ends where adjacent sections are the same 009885 / U26 - ^ - 1S P 15 908 YO9-68-094 3. Transmission line according to claim 1 and 2, characterized in that swi see zv * ei a longitudinal resistance and a transverse resistance associated sections (30A, 30C) each have a section (32B) with a constant value over the entire section for the width of the signal conductor (52) and the distance between the signal conductor (52) and the ground layer (50) is provided, which value is equal to the value at the ends of both adjacent sections associated with a longitudinal or a transverse resistance. 4. Transmission line according to one or more of the preceding Speech, characterized in that the characteristic Impedance in a section (30A, .3OB) assigned to a series resistance decreases almost linearly in the direction of signal flow. 5. Transmission line according to one or more of the preceding Claims, characterized in that the characteristic Impedance in a section assigned to a transverse resistance (30C) increases almost hyperbolically in the signal flow direction, 6. Transmission line according to one or more of the preceding Claims, characterized in that in a X series resistance assigned section (3ÖA, 30B) the * Dielektrikurii is a good insulator and the signal conductor is made of an electrically resistive material and that the spacing of the signal conductor (52) to the mass layer (50) in the signal flow direction steadily decreases and / or the width of the signal conductor increases steadily in the direction of the signal flow 009885 / U26 - 2 »46 P 15 908 Yog-68-094 7. transmission line according to one or more of the preceding Claims, characterized in that in a transverse resistance associated section (300) the dielectric is lossy and the signal conductor is a good electrical conductor and that the distance between the ground layer (50) and the signal conductor (52) increases steadily in the signal flow direction and / or the width of the signal conductor is constant in the direction of signal flow decreases 8. Transmission line according to one or more of the preceding Claims, characterized in that the signal conductor (52) has a constant width over the entire length and that in the first section in relation to the signal flow direction (32A) the dielectric (54) is a good insulator and the signal conductor (52) is a copper conductor or similar good electrical conductor and the distance between the Maesenschien (50) and signal conductor is constant and that in the second section (30A) the dielectric is a good one Is an insulator, the signal conductor (52) made of electrically resistive material and the distance between the reading layer (50) and the signal conductor (52) decreases almost linearly from the value at the adjacent end of the first section, and that in the third section the dielectric (54) eats a good insulator and the signal conductor (52) a good conductor and the Distance between ground layer (50) and signal conductor (52) constant the value at the adjacent end of the second section (30A) has and that in the fourth section (30C) the dielectric (50) is lossy and the signal conductor (52) is a good electrical conductor and the distance between the Mae sens chi cbt (50) and the signal conductor (52) from the value at the adjacent Enc) e of the third section (32D) decreases almost hyperbolically starting and 009885 / U2 6 if P 15 908 Y09-68-094 that in the fifth section (320) the dielectric (54) good insulator and the signal conductor (52) is a good electrical conductor and the distance between the ground layer (50) and the Signal conductor (52) constantly has the value at the adjacent end of the fourth section (300) and that in the sixth section (30D) the dielectric is a good one Is insulator and the signal conductor (52) is made of electrically resistive material and the distance between the ground layer (50) and the signal conductor (52) decreases almost linearly starting from the value at the adjacent end of the fifth section and that in the seventh and last section the dielectric (54) a good insulator and the signal conductor (52) a good conductor and the distance between the mass layer (50) and the signal conductor (52) constantly has the value at the adjacent end of the sixth section (32D) 9 · Transmission line according to one or more of claims 1 to 7, characterized in that the signal conductor (52) via the the entire length has a constant distance from the mass layer (50) and that in the first section in relation to the signal flow direction (32A) the dielectric is a good insulating gate and the signal pus (52), a copper conductor or the like good electrical Conductor and the width of the signal conductor (5.2) is constant and / that in the second section (30A) the dielectric (54) a A good insulator is the signal conductor (52) made of electrically resistive material and the width of the signal conductor (52) is based on the value at the adjacent end of the first section « increasing steadily and almost linearly 00988-5 / 1426 - JS - ^ P 15 908 ΥΟ9-68-Ό94 that in the third section (30A) the dielectric is a good insulator and the signal conductor (52) is a good conductor and everything The width of the signal conductor (52) is constant at the value at the adjacent end of the second section (30A) and that in. the fourth section (300), the dielectric (54) is lossy and the signal conductor (52) is a good electrical conductor and the width of the signal conductor (52) of the value at the adjacent end of the third section decreases almost hyperbolically and that in the fifth section (320), the dielectric (54) is a good insulator and the signal conductor (52) is a good electrical conductor and the width ü & s signal conductor (52) is constant the value at the adjacent end of the fourth section (300), and that in the sixth section (30D) the dielectric is a good one Insulator 1st and the signal conductor (52) is made of dielectric resistance material and the width of the signal is wider (552) starting from the value at the adjacent end of the fifth section increases steadily and almost linearly that in the seventh and last section the dielectric (54) is a good insulator and the signal conductor (52) is a good conductor is and the width of the signal conductor (52) constant the value am adjacent end of the sixth section (32D). 00988S / M26 Empty soap