DE2135311A1 - Torsional waveguide - Google Patents

Description

FATJO NTANWALTY

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W. 530

Augsburg, July 14, 1971 Henry James Ribleb, 35 Edmunds Road, We lies Ley, Massachusetts, V.St.A. 0219 ¹ I. Toreion waveguide

The invention relates to torsional waveguides which are made up of hollow, essentially rectangular conductor sections are formed, which are attached to one another and each with respect to the adjacent section about the longitudinal axis of the torsion waveguide are twisted against each other, whereby the transitions between the individual sections are spaced each about a quarter of the mean wavelength

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of the frequency band for which the torsion waveguide designed 1st,

While generally waveguides for the transmission of electromagnetic Waves are used, especially torsional waveguides are used to rotate the plane of polarization these electromagnetic waves are used,

When transmitting electromagnetic v / rush over Waveguides sometimes require the plane of polarization to twist the waves »In the case of waveguides with a rectangular cross-section, this is usually done by Twisting in the waveguide is achieved. Such torsional waveguides have already been produced by that a section of a straight waveguide with a incompressible substance is filled that then the ends of this ladder section held in place with clamps, the waveguide is twisted to the desired extent and then the filling is removed again. To rotate the plane of polarization by 90 °, a waveguide section is usually used, which has several Wavelengths long. This waveguide section is twisted in such a way that its rotational deformation is uniform is distributed over the entire length. The gradual,

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extending over several wavelengths Twist contributes to a low standing wave ratio.

Torsional waveguide sections are in the process of being manufactured according to the conventional method because of the length of the sections, because of the amount of waste material that results, and because of the multitude of process steps to be carried out. If the cross-sectional deviations, which result from the twisting of the rectangular waveguide, exceed permissible limits, see above they act as a source of reflection for the wave energy. Torsional waveguides made by the conventional process often have unreliable mechanical ones Properties as the final dimensions of the Depend on the hardness of the waveguide material; the electrical properties of such torsional waveguides are because of the Irregularities in the conductor walls where the clamps held the waveguide ends when they were twisted, mostly bad. In addition to the difficulties encountered in making useful torsional waveguide sections, the conventional torsional waveguide for one Use in transmission systems in which minimum cable lengths are required, often impermissibly long.

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From the OcS-PS 3 ÖH6 507 a torsion waveguide is

* welelier from a stack of identical rectangular ones Waveguide sections is composed, each section adjoining the previous one Section is slightly twisted. With this well-known Each section of the stack is made up of torsional waveguides bucket flat disc with a centrally arranged right -opening. Each subsequent Seheibe is opposite yours

Disc * rotated by 10 ° "The inside of this b®lsanaten waveguide looks like a spiral staircase, that is, if you cut directly into the waveguide, you can see spiraling steps, so that one step from one section to the next forms one step at a time partially covered the rectangular opening. In order to bring such a torsion waveguide from stacked sections to a usable performance EU , a large number of sections must be used in order to avoid interference with the transmission of the wave energy through the steps. that a more gradual twisting is achieved, but it also requires its lengthening of the twisted section.

Ss is remarkable that with the known torsion

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waveguides at all points in the range of its length the cross-section is the same. The one formed by deformation Torsion waveguide, this cross section rotates uniformly in the region of the length of the torsion waveguide, while In the case of the stepped torsion waveguide, a fixed cross-section rotates with interruptions at the steps,

A twisted section of a rectangular waveguide has the task of defining the plane of polarization of the electromagnetic transmitted through the section Reorienting waves.

The invention aims to achieve the object of creating a Tor3lon waveguide or section, In which, while maintaining a low standing ratio, the polarization level of the input signal

on the minimum waveguide length by a certain angle is turning.

In terms of solving this problem, tile Invention a torsional waveguide, which is formed from hollow, substantially rectangular conductor sections is attached to one another and in each case with respect to the adjacent section around the longitudinal axis of the Torsionshohlleiteri are twisted against each other, the transitions

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between the individual sections distances of about a quarter of the mean wavelength of the frequency band have «for which the torsion waveguide is designed. Such a torsional waveguide is according to eier invention characterized by inclined walls, which Each form part of the wide walls of the sections and which run between adjacent sections uiKl thereby the normally at the transition between replace pronounced steps occurring in adjacent sections.

In contrast to the known ones described above Torsion waveguide rotates on the torsion waveguide according to the invention, the cross-section in that its shape changes continuously.

In the torsion waveguide according to the invention, which instead of the steps, it has gradual transitions, the plane of polarization without affecting it Performance rotated to a shorter distance than known torsion waveguides.

The torsional waveguide according to the invention is off Basic sections built up with gradual transitions that are joined together in such a way that a continuous Waveguide results. Each round section is roughly a «

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/ ¼ wavelength long and inclined on the broadsides® Walls that cause the plane of polarization of the wave energy propagating through the waveguide alImKhIich is rotated without a sharp one Change in cross-sectional area is present and without a significant amount of electrical power in the sections or magnetic energy is stored. The inclined W ends replace the pronounced steps on the Slopes in the waveguide branches of known ones so-called shear torsion waveguides occur. In the preferred embodiment of the torsion waveguide according to of the invention, the necessary for balancing the remaining transverse inductance of a torsion waveguide section Capacity achieved by a depression in the middle cross-section of the base section, which looks like a "negative" Inductance works.

Several embodiments of the invention are shown in FIG the drawings and are described in more detail below. Show it:

Pig. IΛ the cross section of a right

angular waveguide,

Fig. IB shows the cross section of a reoht-

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Square waveguide with arched Walls on the narrow sides,

Fig. 2 a so-called shear

torsional waveguide, which consists of sections stacked one on top of the other the type shown in Fig. IB is formed,

2A © an equivalent circuit dss in

Fig. 2 illustrated torsion waveguides,

FIg. S an equivalent circuit in which

the shunt inductances are balanced by parallel capacitances,

Fig. 3 is a plan view of the

Shear torsion waveguide,

Fig. 4 the two lower one above the other

stacked sections of the shear toroidal waveguide,

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/ ■ ί

5 shows the stereometric development

of the orbital section of the torsion »waveguide according to the invention,

Pig. 6 an elementary basic section

of the torsion waveguide according to the invention,

the pig. 6k to 6q the changing cross-section M

of the Orundabsohnittes shown in Fig. 6,

Flg. 6h a preferred execution

shape of the circular section of the Torslonshohlleiter3 according to the Invention,

Fig. 7 three to a 90 ° -Torsionshohl- m

ladder assembled basic sections, and

Flg. 8 the development of another

preferred embodiment of the Round section of the torsion waveguide according to the invention.

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213 5 3! 10

In the case of a rectangular waveguide of conventional design asi, the clear width is denoted by a and the clear height by b, as shown in Pig, IA. To facilitate the manufacture of the torsion waveguide according to the invention, it is advantageous to modify the rectangular waveguide of conventional design as shown in Fig. 1B, in that the narrow sides are designed as arcs of a circle with the radius r, the center of which lies on the longitudinal axis of the waveguide, and to use this modified arrangement in the torsion hollow core according to the invention as inlet and outlet openings Height b of the inlet opening of the torsion waveguide (Pig, IB) corresponds to the height of the rectangular waveguide. In addition, the area of the inlet opening is preferably identical to the cross-sectional area a'b of the rectangular waveguide. If the height b and the area of the opening of the rectangular waveguide are known, the radius r of the circle of curvature of the narrow sides of the modified waveguide can be determined by several mathematical process steps in order to

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the identical area to come.

The invention is developed here from a waveguide which has been modified so that its Narrow sides are arcs of a circle with radius r, as shown in Fig. IB. In addition, the To facilitate the explanation and illustration of the invention, it is assumed that the walls of the waveguide are infinitely thin, although they are the electrical conduction ™

2 shows the modified waveguide, which is divided into four sections 1, 2, 3 and k , each section being a straight section of conductor with a length of approximately - ^. / lg is the mean wavelength in the waveguide for the frequency band for which the torsion waveguide is designed. / lg is given by the following expression:

Λ g _{T is} the wavelength in the waveguide at the lower limit of the frequency band and

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the wavelength in the conductor is at the upper limit of the frequency band.

For purposes of explanation, it is assumed that the sections 2, 3 and H have been rotated in the same direction in each case about the longitudinal axis L in such a way that each section encloses an angle θ with the section adjoining it. The angle θ is taken here as an angle of 30o ^ so that the section k is rotated by 90 ° with respect to the section 1, as the plan view in FIG. 3 shows. The arrangement shown in FIG. 2 is referred to as a "shear torsion waveguide".

The degree of rotation of the plane of polarization caused by a section of the shear stress waveguide is determined by the angle θ. In the S ^ herungstorsionshohlleiter each abrupt transition, which results from the large angle θ between mutually adjacent sections, that a considerable part of the wave energy hitting the transition is reflected. It has been determined that such a reflective interruption point behaves as if the visual torsion waveguide consisted of a section of elastic waveguide with sin @ r transverse inductance

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at its center at the point which corresponds to the abrupt transition, and that the size of this transverse inductance is proportional to the twist angle θ. For analytical purposes, the shear torsion waveguide according to Pig. 2A are shown schematically by a straight section of a uniform waveguide, which in each case at intervals of -η | £ along the conductor transverse inductances Ll, L2 _t L3

having. In the torsion waveguide according to the invention, ^

which is an improvement on the shear torsion waveguide is the shear inductance of each section in Frequency band center balanced by parallel capacitances Ci or, C2 or C3, as in Pig. 2B. Through the Geometry of the torsion waveguide according to the invention, the quality Q of the resonance circuits is reduced to a minimum reduced.

To get the one in Pig. 2 shown shear torsion * -

Keeping waveguides as short as possible will be the least- ^ possible number of waveguide sections used, which • overlap the narrow walls by the twist angle θ cause · This means corresponding to the example shown in Fig. 3 that the arc-shaped Walls of section i the arcuate walls of Absehn ittes 2 overlap that welter the

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arc-shaped walls of the portion 3, the arcuate walls of the sections 2 to overlap, and in that, finally, the curved walls of the section ¹ I overlapping the arc-shaped walls of the sections 3, if to reduce the light reflected by the twisted waveguide wave energy, a longer twisted waveguide is applicable, more Sections are used and the angle Θ can be reduced to give a more gradual rotation of the plane of polarization,

In Pig, 4 only sections 1 and 2 of Sohepimgotoraiomjhühliei & ora are shown. At the transition between the two sections there are four distinct steps S1, 82, 03 and tttl , which are closed off by electrically conductive flats so that the wave energy remains enclosed within the waveguide. It can be seen from this that the cross-sectional area of the hollow core opening is suddenly reduced at the transition. The electrical effect of this abrupt transition is the formation of a transverse inductance, as shown in FIG. 2A, the magnitude of which changes with the angle of rotation θ. In the torsion waveguide according to the invention, which improves the shear torsion

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represents waveguide, the sudden change in the cross-sectional area of the waveguide opening at the transition in the Shear torsional waveguide avoided by replacing each pronounced step a slope or a gradual "step", i.e. a gradual transition, is provided.

The basic element of the preferred embodiment of the Torsion waveguide according to the invention is from the Shear torsional waveguide in Fig. 4 developed by ^ each of the conductor sections 1 and 2 is divided into two equal parts, as in Pig. 4 by dash-dotted lines shown. Only parts IA and 2A shown in FIG. 5 are initially considered. The lower corners of part IA are labeled A, B, C, D and the upper corners of part 2A are labeled E, F, G and H. The points where the wide walls of parts IA and 2A meet, are denoted by M and N. In order to replace the stage S1 with a gradual transition, the points A, ^ M, E laid an inclined plane. The level AME intersects the broad side wall of the lower part IA and forms the Track AM and intersects the upper part 2A and forms the track EM on its wide wall. Assume that the two parts IA and 2A by a vertical circle

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cylinder 10 are limited with the radius r, which is indicated by dashed lines in Fig. 5, the plane AME forms the track AE on the cylinder jacket. The part of the plane AME ₉ which is delimited by the aforementioned tracks thus becomes an inclined wall of the torsion waveguide instead of the pronounced step S1. The corner EJMK is thus cut off from the part 2A by the inclined wall, while the corner AJLM has been added to the part IA by this inclined wall.

In the same way, the step S2 is through a replaces an inclined wall bounded by the traces of a plane passing through the points BEF; the Step S3 is replaced by a sloping wall, which is made up of traces of a CNG point Level is limited; the step S4 is through a skew Wall, which is delimited by the traces of a plane passing through the points DNH. Of the Basic section with a gradual transition of the preferred embodiment of the torsion waveguide according to the invention therefore has the shape shown in FIG. In the basic section, the triangular wall ABM is parallel to the triangular wall is DCN, and the triangular wall is EMF

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parallel to the triangular wall HWG, as these walls remain from the original parts IA and 2A. the triangular wall AME and wall DNH are inclined with respect to the remains of the original walls. The triangular wall is GNO and its opposite wall is BMF a was also inclined, with respect to the remaining walls, to their However, slope is the slope of the inclined walls QNC and DNH opposite.

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FIGS. 5A to 6G show the arrangement of successive cross-sections, each at right angles to the longitudinal axis L of the round section shown in FIG. As shown in FIG. 6k , the inlet opening ABCD has a generally rectangular cross-section, although it can be seen that the narrow walls are not straight, but rather curved. When making successive cross-sections upward from the inlet opening, the cross-section changes from a slightly serpentine shape, as shown in FIG. 6B, to a more pronounced serpentine shape, as shown in FIG. 6C. The middle parts Pl and P 2 of the serpentine shape decrease in length when the successive cross-sections approach the centers M and N of the base section. Of the

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ti

The cross-section passing through the central points H and N is generally rectangular in shape, as shown in FIG. 6D. If one moves upwards from there, the cross-section again assumes a serpentine shape, as in Pig. 6E with the length of the central portions Ql and Q2 increasing in length as shown in Fig. 6P until the cross-sectional configuration at the outlet port EFGH returns to a generally rectangular shape as shown in Fig. 6Q .

The wave energy propagating through the base section with the gradual transition meets on the inclined surfaces. As a result, the plane of polarization of the wave energy when passing the ground " section rotated by the angle θ. The basic sections are stacked on top of each other so that a torsional waveguide results that the required rotation the plane of polarization. From the point of view of electrical efficiency, the effect is gradual Transition is a noticeable reduction in the magnitude of the shunt inductance that occurs in the equivalent circuit. if therefore the remaining shunt inductance is balanced with a parallel capacitance, as symbolically in FIG. 2B

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■ fs

shown, the resulting resonance circuit has a very low Q. The parallel capacitance can be generated, for example, that capacitive Screws are used to facilitate leveling the base sections in the wide walls of the Torsional waveguide are used. Such adjustment screws are preferably at the "centers" M or N in the base portion shown in FIG. 6. Preferably, however, the shunt inductance of the basic bar is shown in the middle as shown in FIG. 6X1 arranged wells 6 and 7 matched, which give the relevant base section the required "negative" Add inductance. The depressions 6 and 7 are sectors of a circular ring 8 surrounding the base section. Through them, the distance between the narrow walls of the waveguide enlarged. In the case of a 30 ° torsion waveguide section with depressions as in Figure 6h has a standing wave ratio no greater than 1.02 over a full waveguide frequency bandwidth achieved.

In the gradual transition basic portion shown here, the angle θ x was set to 30 ° for the sake of explanation. By joining three

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Grundabsehnltten 1O ₉ 11, 12 of FIG. 7 is formed a waveguide assembly which rotates the polarization plane by an angle of 90 ° in a Torsionshohlleiter whose length approximately λ 3, is κ. By adding more basic sections, the plane of polarization can be rotated through a larger angle. In practice it has been found that better results can be achieved if the length of each basic section is a little greater than -% &.

The equivalent circuit for the torsional waveguide shown in FIG. 7 is shown in FIG. 2B. Since the twist angle is the same for each basic section in FIG. 7 is, applies to the shunt inductance Ll * L2 «L3. As the resonance frequencies of the balanced circuits respectively are the same, then L1C1 * L2C2 * L3C3 · become a matter of course Circuits of the type shown in Fig. 2B, which are in resonance at the same frequency, characterized by their shunt inductance, which, as already mentioned above, is proportional to the twist angle θ. Determining the relative angles of a number of basic sections that connected in cascade to generate a certain total rotation is equivalent to finding the relative values of the inductances Ll, L2, L3 in Fig. 2B,

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when the input standing wave ratio is fixed for a specific frequency band. This problem has already been investigated in the technical literature by a large number of authors. In the publication "The Application of a New Class of Equal-Ripple Functions to some Familiar Transmission Line Problems", Henry J. Riblet, IEEE Transactions on Microwave Theory and Techniques, Volume MTT-12, No. 4, July 1964, pages 415 - 421, an ™ exact theory for solving a problem is given which approximates very closely to the problem associated with the equivalent circuit in FIG. 2B. By applying this theory to the design of torsional waveguides for the usual "waveguide band", for example for the band from 8200 MHz to 12400 MHz intended for a WR-90 waveguide, it results that the same waviness is achieved for a torsional waveguide formed from three sections If the twist angles for all three "sections are approximately the same. For a torsional waveguide consisting of four sections, however, the two middle sections should have the same twist angle, while the end sections should have a twist angle amounting to about 80 % of the twist angle of a central section. Therefore, will at

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the 90 ° torsion waveguide formed from three sections according to FIG. J, the angle of rotation of the base section is selected as 30 °, since this torsion waveguide should work in the entire waveguide frequency band.

The power transmission capability of the torsional waveguide according to the invention with gradual transitions is almost equal to the power transmission capability of the conventional long torsional waveguide, and it is considerably better than the power transmission capability of the shear torsional waveguide as the torsional waveguide with the gradual transitions does not have the sudden cross-sectional constrictions that are present at the transition points in the shear-torsional waveguide.

In the preferred embodiment of the torsional waveguide according to the invention, a gradual Transition in the form of an inclined side wall, as explained with reference to FIG. 4, for example by the Level AME, formed. As a result, the entire length of about -ητ ^ of the base section is used, as the plane passes through corners A and E. The entire length of the base section does not have to be used, however, since the side wall is so deep as shown

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in Fig. 8 can also be formed in that a Level is laid through the points RMS. However, the inclination of the plane RMS relative to the vertical takes place less gradual than the slope of the plane AME. Eb results therefore an impairment of the performance of the torsion waveguide, if not the entire length of the Basic section is used for the sloping walls. However, a useful torsional waveguide can be made are used for the gradual transition, although slightly less than the full length of the base section will. Although the word "plane" used to describe the area AME and other surfaces have been used, it is clear that curved surfaces could also be used to achieve the same results.

Although in the preferred embodiment of the Toreion waveguide according to the invention the base section has a length of approximately - ^, this length is not a fundamentally required feature of the invention. If the length of the round section deviates considerably from a quarter wavelength, the balanced circuits in the equivalent circuit are not arranged at intervals of -η ^ .

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Claims (1)

Patent claims: 1. Torsionshohlleiter, "richer of hollow, is formed substantially rectangular conductor sections which are attached to each other and are each twisted against each other relative to the adjacent section about the longitudinal axis of the Torsionshohlleiters, wherein the transitions between the individual sections distances of approximately one quarter of the Have a bitter wavelength of the frequency band for which the torsion waveguide is designed, characterized by inclined walls (AME, BEF, CNO, DNH), each of which is part of the width Walls of the sections (1, 2, 3, * or IA, 2A or 10, 11, 12) and which run between adjacent sections and thereby normally at the transition between Replace adjacent sections occurring pronounced steps (S1, S2, SjJ, S4). 2. Waveguide according to claim 1, characterized by parallel capacitance devices (Cl, C2, CJ), which with the remaining shunt inductance (Ll, L2, L3) form a resonance circuit. - 24 - 109884/1355 3. Waveguide according to claim 2, characterized in that the parallel capacitance devices (Cl, C2, CJ) are depressions (6, 7) which are opposite one another are formed in the narrow walls of the waveguide. 4. Waveguide according to one of claims 1 to j3, characterized in that the inclined walls essentially have the shape of triangles (AME, BEF, CNG, DNH) U , each of which has a corner at an intersection (M, N) between the inner wide walls together adjacent sections (IA, 2A). 5. Waveguide according to one of claims 1 to 4, characterized in that its narrow walls Im Cross-section are the bends of a circle, the center of which is on the longitudinal axis (L) of the section rotation lies. G 6. Waveguide according to claim 3 and 5 # thereby characterized in that the arcuate narrow walls the opposing inner recesses (6, 7) which have the parallel capacitances (Cl, C2, C ^) form, those with the, the transitions between each other adjacent sections (IA, 2A) associated remaining shunt inductances (Ll, L2, L3) are in resonance. - 25 - 1 0 0 8 fc 4 / j 3 t, b 7 * waveguide according to one of claims 1 to 7 with rectangular inlet and outlet openings, characterized in that the inclined walls are arranged in this way are that successive, to the longitudinal axis of the torsion waveguide cross-sections at right angles gradually from a generally rectangular shape to a generally serpentine shape and back again to a general one Change rectangular shape (Fig. 6A to 6g). 8. Waveguide according to one of claims 1 to 7, characterized in that the non-inclined parts (ABM, DCN, EMF, HNG) of the wide walls are parallel to the torsion waveguide longitudinal axis (L). 9 * Waveguide according to one of claims 1 to 8, characterized in that the tandem arrangement interconnected sections (10, 11, 12) form a continuous waveguide and that each section each having a generally rectangular cross-section (ABCD, EFGH) at its ends. - 26 - 1 0 9 8 8 4/1355