DE2053852A1 - Quasi-plush broadband switch in waveguide design - Google Patents

Description

Licentia-Patent-Verwaltungs-GmbH. PT-BK / Thn / »a

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Quasi-optical broadband crossover in waveguide design

The present invention is concerned with a quasi-optical broadband switch in waveguide design with at least a high-frequency input and at least one high-frequency output, with input and output each via one four-armed, symmetrical, signal voltage branching Directional couplers are connected to one another in such a way that between the directional coupler η two equal length «each with a deflecting mirror provided side arms are arranged in which a phase rotation is generated between the two signals. The directional couplers must be independent of the designation chosen of the accesses in the lossless case have a scatter matrix that is symmetrical with respect to both diagonals is.

Titled "Band-splitting filter" is by Marcatili

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and Bisbee ie Bell System Technical Journal, vol. kO (196l), 197 - 212, a switch in front of ("sleep, old the broad frequency bands in the millimeter-wave area can be separated from each other. This is shown in the figure 1 of the drawing i" scheme and works old quasi-optical round waveguide components, which lead the H ^ ₁ "wave. It consists of two directional couplers A and B, each of which has four connection terminals 1 to k and is connected to one another via two side arrows X and XX . An incoming high-frequency signal that is applied to terminal 1 of directional coupler A is divided equally between terminals 2 and 3. Signals whose frequencies fu are below the cut-off frequency of the interconnected high-frequency signals are reflected and are added in phase at terminals k and can be picked up at this terminal. Signals with frequencies fo above the cut-off frequency of the connected high-pass filters are sent to the second n Directional coupler B and appear at its terminal 3 when the phase response of the side arms X and XX is the same. Within this line routing, the signals are deflected at a deflecting mirror in each side arm. A crossover of this type works satisfactorily when the lower and upper band together do not significantly exceed a frequency range voft approximately one octave.

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2053862

In a further article "Broad-band directional couplers" by Marcatlli and Ring in IRE Tran ".MTT, July 1962, 251-257" it is shown that one can increase the bandwidth of the transmitting upper part almost as desired if one is in both side arms that lead cum directional coupler B, phase shifters φΐ and <p2 inserted, which cause a phase difference between the two signals in the two side arms, which is φΐ ~ ψ2 «(2n + l) * (n * 0,1,2 · .. ). The transmitted signal appears in the upper band at the terminal of the directional coupler B. In this article, the proposal is made to insert two waveguide sections of different lengths and different diameters for the practical construction of this arrangement, whereby the length of the side arms must nevertheless be exactly the same. Fulfilling this strict requirement runs into considerable difficulties in practice, mainly because suitable transitions with the same phase response are difficult to implement.

In the patent application under the file number P 20 19 0 ^ 9 * 2 has already been proposed to overcome the difficulties just mentioned by inserting phase-rotating elements in the Avoid side arms, whereby a phase-shifting dielectric load is inserted into a cable run. These Arrangement is complex and expensive in practice and there is therefore the task of finding an arrangement that one Simplification of this arrangement represents and is cheaper to manufacture.

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According to the invention, this object is achieved in that the deflection mirrors are provided with different dielectric coverings, the dielectric coverings having different thicknesses. A very broadband switch is obtained if at least one layer is made up of at least two dielectric sub-layers with different dielectric constants exist, wherein the dielectric constants can have complex values. With this one Embodiment, the pads are dimensioned so that a phase difference is generated in the side arms, which in a given range of variation of (2n + 1) .18O ° with η «0,1,2 ... fluctuates * In the exemplary embodiment, η β Ο chosen.

The invention is described in more detail using exemplary embodiments with the aid of the drawing. Show it

Fig. 1 shows a band switch for the H ^ -wave according to Marcatili and Bisbee,

FIG. 2 shows a band switch for the H °. wave according to Mar-

oil

catili and ring,

Fig. 3 shows a broadband switch with dielectrically coated Reflect,

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FIG. k is a diagram in which the phase angle is plotted as a function of η / λ,

5 examples of the achievable phase difference between two dielectrically coated mirrors,

6 shows a deflecting mirror coated with dielectric and

7 shows a diagram with a different dielectric coating of the deflecting mirrors.

Figures 1 and 2 have already been explained in more detail in the description.

In the figure 3 the embodiment according to the invention of a broadband switch is shown in one embodiment. The two directional couplers are designated A and B, each of which has four terminals 1, 2, 3 and k . Terminal 1 of the directional coupler A is the input of the high-frequency signal consisting of the frequencies fu and fo. This high-frequency signal is split between terminals 2 and 3 and reaches the high-pass filters HP1 and HP2. Here the two frequencies fu and fo are separated, the frequencies fu being totally reflected, both components appearing again in the directional coupler A and being delivered to the terminal k in the correct phase. The frequency parts fo become the high-pass filters HP1

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and HP2 pass and reach the deflecting mirrors SpI and Sp2 and are deflected in their direction at these mirrors and appear at terminals 1 and h of the Rient Coupler B. These mirrors SpI and Sp2 have a dielectric coating that can be designed in different ways « If, for example, they have the same number of layers and the same thickness and the same dielectric properties, the deflection at both mirrors will be the same. If the properties of these dielectric coatings are different, for example same thickness and different dielectric, different thickness and same dielectric or different thickness and different dielectric, the two signals appearing at terminals 1 and 4 of directional coupler B will have different phases. Likewise, the number of dielectric coatings on each mirror can be different.

However, according to Marcatili and Ring, there is now a phase difference of (2n + l) .l80 ° because of the required broadband of the System must be achieved, these options are available, depending on how you acted on this deflection mirror. The output signal is then on the terminal of the directional coupler B is available. Terminal 3 of this directional coupler can be terminated with an adapted absorber will.

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Figure k shows the diagram in which the phase angle φ is plotted as a function of h / λ, where h is the thickness of the dielectric support on the deflecting mirror and X is the operating wavelength; it is the respective dielectric constant of the material being examined as a parameter. It can be seen from this that phase rotations of several hundred degrees can be easily achieved by choosing different dielectric constants and thicknesses.

The diagram in FIG. 5 shows the phase difference that can be achieved between two dielectrically coated mirrors with different dielectric, with the phase difference φΐ- φ2 is plotted against hl / λ. h 1 is the thickness of the dielectric coating of a mirror and λ the operating wavelength of the transmitted signal. Bs is easy to see that in this way the frequency range of the upper band can be extended to over an octave.

FIG. 6 shows the practical embodiment of a deflecting mirror in section as an example of execution. By doing Waveguide H, which is designed as an elbow, is at the kink at an angle of ^ 5 ° to the respective transmission direction a mirror Sp, which is provided with a dielectric coating D, is arranged. This covering can consist of one or consist of several layers, which are optional in their thickness and

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their dielectric properties can be varied. "To the Bracket of this mirror arrangement is a plan F with the waveguide H connected.

Coating the mirror with is particularly advantageous several dielectric layers with different dielectric constants · This achieves a further one Increase in the bandwidth · This can be seen from diagrams B and C in FIG. 7 · In contrast, curve A of the diagram shows the course with a simple coating of both mirrors. The permitted deviation from 180 ° for curves A and B 17 assumed · The curve C exceeds this value somewhat · The permissible range of variation can in principle be freely selected can be selected, it only has an effect on the attenuation. The following table shows the parameters for the curves of the diagram. The first index number relates to the mirror and the second index number

on the layer, e.g. e 21: 2 «mirror 2Jl = layer 1.

Tabel;

A. c _r l ■ 2.05 H2 / H1 = 1.666 c 2 = 2.8

B. c _r ll = 2.0 ^H ₁₂ ^{/ H} ii = ¹ » ²

e _r 12 = 2.6 ^H 2iii

c _r 21 . k, 6 H ₂₂ ZH ₁₁ = 1.7

c _r 22 = 3.8 ^H 22ll

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C. e _r ll * 1.8 H ₁₂ / H _tl m 0.8

e _r 12 = 2.0 H ₂₁ / H ₂₁ χ 0.7 c _r 21 = 7.2 H ₂₂ ZH ₁₁ «1.1 C-22 = 5.2

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Claims (1)

Claims (I) / Quasi-optical broadband switch in waveguide design »it »At least one high-frequency input and at least one High frequency output, with input and output above each a quadruple, symmetrical, signal voltage branching directional coupler are connected to one another in such a way that between the directional couplers two equally long, with each a deflection mirror provided side arms are arranged in which a phase rotation between the two Mirror is generated, characterized in that the deflection mirrors (SpI, Sp2) are provided with different dielectric coatings « 2) Quasi-optical broadband switch according to claim 1, characterized in that the dielectric coverings have different thicknesses 3) Quasi-optical broadband switch according to one of the preceding claims, characterized in that at least a layer consists of at least two dielectric sub-layers with different dielectric constants k) Quasioptiscbe broadband switch according to one of the preceding claims, characterized in that the Dielek- BK 70/25 - 11 - 209821/0177 trika have different complex dielectric constants. 5) Quasi-optical broadband switch according to claim 1, characterized in that indicates that the dielectric coverings are dimensioned in such a way that a phase difference of (2n + l) .18O ° - a selectable range of variation is generated, where η »0,1,2 ··· is. BK 70/25 209821/0177