WO2018220196A1

WO2018220196A1 - Microwave component having an asymmetric propagation chamber

Info

Publication number: WO2018220196A1
Application number: PCT/EP2018/064506
Authority: WO
Inventors: Anthony Ghiotto; Frédéric PARMENT; Ludovic Carpentier
Original assignee: Université De Bordeaux; Centre National D'etudes Spatiales; Institut Polytechnique De Bordeaux; Centre National De La Recherche Scientifique
Priority date: 2017-06-02
Filing date: 2018-06-01
Publication date: 2018-12-06
Also published as: FR3067173A1; FR3067173B1

Abstract

A microwave component (10) having an upper layer (14), a lower layer (16), and a core layer (18) defining a propagation zone (19) of an electromagnetic wave extending along a propagation axis (X-X), the propagation zone (19) comprising at least one symmetrical propagation chamber (28). The propagation zone (19) further comprises an asymmetrical propagation chamber (32) defined by the upper layer (14), the lower layer (16) and two spaced-apart lateral boundaries (34, 36) suitable for preventing the passage of an electromagnetic wave having a wavelength greater than or equal to a predetermined minimum wavelength, the lateral boundaries (34, 36) of the asymmetric chamber (32) being non-symmetrical in relation to any plane parallel to the plane of symmetry.

Description

Microwave component having an asymmetric propagation chamber

The present invention relates to a microwave component comprising a waveguide comprising at least one upper layer having an electrically conductive lower surface, a lower layer having an electrically conductive upper surface, and a central layer defining a propagation zone of a electromagnetic wave, the propagation zone extending along an axis of propagation; the propagation zone comprising at least one symmetrical propagation chamber delimited by the lower surface of the upper layer, the upper surface of the lower layer and two spaced symmetrical lateral boundaries; the lateral boundaries of the symmetrical chamber being adapted to prevent the passage of an electromagnetic wave having a wavelength greater than or equal to a predetermined minimum wavelength; the lateral boundaries of the symmetrical chamber having a plane of symmetry parallel to the axis of propagation and orthogonal to the lower surface of the upper layer and the upper surface of the lower layer.

It is known to use planar or waveguide technologies for producing microwave components providing a filter function of an electromagnetic wave.

One of the functions of such a filter is to reject frequencies. Often, it is necessary to reject frequencies very close to the bandwidth of the filter.

Current planar structures are compact, lightweight, with low manufacturing cost, but are limited in terms of overvoltage coefficient.

Current waveguides have low insertion losses, good selectivity, a high quality factor, but they are cumbersome, expensive and their integration with the planar circuits is difficult.

An object of the invention is therefore to provide a simple microwave component for providing a filtering function having good off-band rejection while being compact and low cost.

To this end, the subject of the invention is a microwave component of the aforementioned type, characterized in that the propagation zone further comprises an asymmetric propagation chamber delimited by the lower surface of the upper layer, the upper surface of the lower layer and two spaced apart lateral boundaries to prevent the passage of an electromagnetic wave having a wavelength greater than or equal to the predetermined minimum wavelength; the lateral boundaries of the asymmetrical chamber being devoid of symmetry with respect to any plane parallel to said plane of symmetry. The microwave component according to the invention may comprise one or more of the following characteristics, taken separately or in any technically possible combination:

each lateral boundary of the asymmetric chamber is connected to an adjacent lateral boundary of the symmetrical chamber;

at least one of the lateral boundaries of the asymmetrical chamber protrudes from the adjacent lateral border away from the other side boundaries of the asymmetrical chamber in a direction transverse to the axis of propagation;

at least one of the lateral boundaries of the asymmetrical chamber protrudes towards the other side of the asymmetrical chamber along a transverse direction to the axis of propagation from the adjacent lateral boundary;

at least one of the lateral boundaries of the asymmetrical chamber is aligned with said adjacent lateral boundary;

at least one of the lateral boundaries of the asymmetrical chamber comprises a diverging portion;

said first lateral boundary further comprises a converging portion;

the divergent portion and / or the convergent portion present (nt), in projection on a plane orthogonal to said plane of symmetry, a predetermined profile chosen from: a straight line, an exponential profile, a sinusoidal profile, a Klopfenstein profile;

said first lateral border further comprises a rectilinear part, parallel to the axis of propagation;

at least one of said lateral boundaries of the asymmetric chamber comprises a row of vias arranged through the central layer, the spacing between two successive vias of the row being less than the predetermined minimum wavelength, for example less than or equal to at one fifth of the determined minimum wavelength;

at least one of said side boundaries of the asymmetrical chamber comprises an electrically conductive plate;

the central layer is at least partly made of a dielectric material, and the propagation zone comprises an internal cavity delimited by the lower surface of the upper layer, the upper surface of the lower layer and the lateral edges of the central layer, the lateral boundaries of the asymmetrical chamber being disposed outside the internal cavity;

one of the lateral edges of the central layer, disposed in the asymmetric chamber, projects towards the other lateral edge of the central layer in a direction transverse to the axis of propagation; in the asymmetrical chamber, the maximum distance between one of the lateral edges of the cavity and the lateral border closest to said lateral edge, along an axis orthogonal to the axis of propagation, is greater than 0.25 mm, and;

- The asymmetrical chamber is disposed at one end of the propagation zone, along the axis of propagation.

The invention will be better understood on reading the description which follows, given solely by way of example, and with reference to the appended drawings, in which:

- Figure 1 is a schematic horizontal section in top view of a first embodiment of a component according to the invention;

- Figure 2 is a schematic vertical section in longitudinal view along the X-X axis of the component of Figure 1;

FIGS. 3 and 4 are simulation comparisons between the component of FIG. 1 and a component devoid of an asymmetrical chamber;

- Figures 5 to 16 schematically illustrate different embodiments of a component according to the invention.

A first embodiment of a microwave component according to the invention is illustrated in FIG.

In the embodiment of the figures, the microwave component is a filter, in particular a microwave pass-band filter having a determined bandwidth.

The microwave component 10 is here of the "guide integrated in the substrate" type.

It comprises a waveguide 12 adapted to guide an electromagnetic wave along an axis of propagation XX, between an input 13A and an output 13B, the electromagnetic wave having a wavelength greater than or equal to a length of predetermined minimum wave, said wavelength being predetermined by the frequency to be addressed by the microwave component 10.

The minimum wavelength is typically between 3 μηι and 3 m.

The waveguide 12 comprises an upper layer 14, a lower layer 16, and a central layer 18 defining a propagation zone 19 of the electromagnetic wave extending along the X-X propagation axis.

Each of the upper layer 14, the lower layer 16 and the central layer 18 extends in a plane XY, defined by the axis of propagation XX and a transverse axis YY orthogonal to the axis of propagation XX. Each of the upper 14, lower 16 and central 18 layers has an electrically conductive upper surface 20A, 20B, 20C and an electrically conductive lower surface 21A, 21B, 21C.

The lower layer 16 and the upper layer 14 are arranged at a distance from one another, on either side of the central layer 18, in contact with the central layer 18.

In particular, the lower surface 21A of the upper layer 14 is in contact with the upper surface 20C of the central layer 18. Similarly, the lower surface 21C of the central layer 18 is in contact with the upper surface 20B of the lower layer 16.

Thus, the upper layer 14, the lower layer 16 and the central layer 18 form a stack.

The lower surface 21A of the upper layer 14 is electrically connected to the upper surface 20C of the central layer 18. Similarly, the lower surface 21C of the core layer 18 is electrically connected to the upper surface 20B of the lower layer.

In the remainder of the description, the term "transverse direction" Y-Y will be called a direction parallel to the transverse axis Y-Y.

A transverse direction is therefore a direction orthogonal to the axis of propagation X-X and parallel to the lower surface 21 A of the upper layer.

In a preferred embodiment, each of the upper 14, lower 16 and central 18 layers forms a substrate.

Each of the upper 14, lower 16 and central 18 layers thus comprises an electrically conductive upper sub-layer 22A, 22B, 22C, an electrically conductive lower sub-layer 24A, 24B, 24C and a dielectric core sub-layer 26A, 26B, 26C , having a first dielectric constant, interposed between the upper sub-layer 22A, 22B, 22C and the lower sub-layer 24A, 24B, 24C.

Subsequently, the term "electrically conductive element" means that said element has an electrical conductivity greater than 1 ^× 10 ⁶ S. m ^-1 , preferably equivalent to that of a metal of the copper, silver, aluminum or gold type. .

Subsequently, the term "dielectric element" means that said element has a relative dielectric permittivity greater than or equal to 1.

In addition, the lower sub-layer 24A of the upper layer 14 is electrically connected with the upper sub-layer 22C of the central layer 18. Similarly, the lower sub-layer 24C of the central layer 18 is electrically connected with the sub-layer. upper layer 22B of the lower layer 16. The upper sub-layers 22A, 22B, 22C and the lower sub-layers 24A, 24B, 24C are for example made of copper.

The central sub-layers 26A, 26B, 26C are for example made of epoxy resin or Teflon.

The propagation zone 19 corresponds to a zone of the waveguide 12 in which the electromagnetic wave is confined during its propagation in the waveguide 12.

The propagation zone 19 comprises a symmetrical propagation chamber 28 delimited by the lower surface 21 A of the upper layer 14, the upper surface 20B of the lower layer 16 and two spaced lateral boundaries 30.

The propagation zone 19 further comprises an asymmetrical propagation chamber 32. The asymmetric propagation chamber 32 is delimited by the lower surface 21 A of the upper layer 14, the upper surface 20B of the lower layer 16, a first lateral boundary 34 and a second lateral boundary 36 spaced from the first lateral boundary 34.

The propagation zone 19 further comprises an internal cavity 38 delimited by the upper 14, lower 16 and central 18 layers, and extending from the symmetrical chamber 28 to the asymmetrical chamber 32.

The internal cavity 38 is delimited by the lower surface 21A of the upper layer 14, the upper surface 20B of the lower layer 16 and the lateral edges 40A, 40B of the central layer 18.

The internal cavity 38 is filled with a fluid 42 having a second dielectric constant, for example less than the first dielectric constant.

The fluid 42 is for example air. Alternatively, in the case where the internal cavity 38 defines a sealed closed volume, it is filled with air, nitrogen or is empty of fluid.

In the symmetrical chamber 28, as illustrated in FIG. 1, the lateral edges 40A, 40B of the central layer 18 run along the lateral boundaries 30 of the symmetrical chamber 28.

By "longer" is meant that the lateral edges 40A, 40B are in contact with said lateral boundaries 30 or disposed at a constant distance from said lateral boundaries 30, for example less than 100 μηι.

In the asymmetric chamber 32, in the example illustrated in FIG. 1, the lateral edges 40A, 40B of the central layer 18 extend parallel to the axis of propagation X-X.

In the following, the lateral edge disposed in the asymmetrical chamber 32 closest to the first lateral border 34 will be referred to as "first edge lateral "and by the general reference 40A. Similarly, the side edge disposed in the asymmetric chamber 32 closest to the second lateral border 36, will be referred to as the "second side edge" and the general reference 40B.

The lateral edges 40A, 40B are advantageously covered with an additional dielectric layer, not shown. In a variant, the lateral edges 40A, 40B may be metallized, that is to say, covered with an electrical conductor.

The lateral edges 40A, 40B present, in the symmetrical chamber 28 and also in the asymmetric chamber 32 in this example, a plane of symmetry parallel to the axis of propagation XX and orthogonal to the lower surface 21A of the upper layer 14 and at the upper surface 20B of the lower layer 16.

The symmetrical chamber 28 comprises a plurality of propagation sub-chambers 44, illustrated in FIG. 1, extending along the X-X propagation axis, delimited laterally by the two lateral boundaries 30 of the symmetrical chamber 28.

The lateral boundaries 30 of the symmetrical chamber 28 are symmetrical with respect to said plane of symmetry.

They are orthogonal to the lower surface 21 A of the upper layer 14 and to the upper surface 20B of the lower layer 16.

The lateral boundaries 30 of the symmetrical chamber 28 are adapted to prevent the passage of an electromagnetic wave having a wavelength greater than or equal to the predetermined minimum wavelength.

As illustrated in FIG. 2, at least one of the lateral boundaries 30 of the symmetrical chamber 28 comprises a row of electrically conductive vias 45 arranged through the central layer 18.

"Via" means a hole, arranged at least through the central layer 18, having walls covered with an electrically conductive coating, for example a coating made of metal.

Each via 45 extends along an axis Z-Z orthogonal to the axis of propagation X-X and to the transverse axis Y-Y, passing through at least the central layer 18.

The spacing between two successive vias 45 of the row is less than the predetermined minimum wavelength, for example less than or equal to one fifth of the predetermined minimum wavelength.

Alternatively, or in addition, at least one of the lateral boundaries of the symmetrical chamber 28 comprises an electrically conductive plate, for example a coating made of metal. Each sub-chamber 44 of propagation is connected to an adjacent sub-chamber 44 by a connection passage 46, also called IRIS, delimited by the two lateral boundaries 30 of the symmetrical chamber 28.

Each sub-chamber 44 is symmetrical about the plane of symmetry of the symmetrical chamber 28. Each sub-chamber 44 here has a substantially rectangular shape.

More specifically, in each sub-chamber 44, each of the two lateral boundaries 30 of the symmetrical chamber 28 has a longitudinal portion 48 parallel to the axis of propagation XX, connected to at least one of the connection passages 46 by a transverse portion 50 parallel to the transverse axis YY.

The spacing in the Y-Y direction between the two longitudinal portions 48 of a sub-chamber 44 is variable from one sub-chamber 44 to another.

At least one of the sub-chambers 44 is, in known manner, able to reject a first predetermined frequency f1 below the bandwidth [f. _3dB ; f ' _-3 dB] of the filter formed by the microwave component 10.

The asymmetric propagation chamber 32 is adapted to reject a second predetermined frequency f2 above the bandwidth [f _-3d B; V. _3dB ] of the filter formed by the microwave component 10.

By "reject a second predetermined frequency f2" is meant that the component 10 has a predetermined transmission zero at the second frequency f2, that is to say, a weakening of the important signal, not allowing to transmit a wave. In particular, it is meant that the amplitude, measured at the output of the waveguide 12, of an electromagnetic signal having the second predetermined frequency f2, has a loss greater than 5 dB relative to the amplitude, measured at the output of the guide 12 of a signal having a resonance frequency of the waveguide 12.

The asymmetric chamber 32 is disposed at one end of the propagation zone 19, along the propagation axis XX, in particular at the output 13B of the waveguide 12. In a variant, it is arranged at the input 13A of the waveguide. wave 12.

The lateral boundaries 34, 36 of the asymmetrical chamber 32 are devoid of symmetry with respect to any plane parallel to the axis of propagation XX and orthogonal to the lower surface 21A of the upper layer 14 and to the upper surface 20B of the layer lower 16.

The lateral boundaries 34, 36 of the asymmetric chamber 32 are, for example, orthogonal to the lower surface 21A of the upper layer 14 and to the upper surface 20B of the lower layer 16. They are able to prevent the passage of an electromagnetic wave having a wavelength greater than or equal to the predetermined minimum wavelength.

According to one embodiment, at least one of the lateral boundaries 34, 36 of the asymmetrical chamber 32 comprises a row of electrically conductive vias, arranged at least through the central layer 18. The spacing between two successive vias of the row is lower at the predetermined minimum wavelength, for example less than or equal to one fifth of the determined minimum wavelength.

Alternatively, or in addition, at least one of the lateral boundaries 34, 36 of the asymmetrical chamber 32 comprises an electrically conductive plate, for example made of metal.

As illustrated in FIG. 1, the first lateral frontier 34 and the second lateral frontier 36 of the asymmetrical chamber 32 are respectively connected to an adjacent lateral boundary 30 of the symmetrical chamber 28.

By "connected" is meant that one end of the lateral border 34, 36 of the asymmetric chamber 32 is in contact with its adjacent lateral boundary 30 or disposed at a distance from its adjacent lateral border 30 less than the length predetermined minimum wave, preferably less than or equal to one-fifth of the determined minimum wavelength.

In particular, each lateral boundary 34, 36 of the asymmetric chamber 32 is connected to the longitudinal portion 48 of its respective adjacent lateral boundary 30.

In other words, the waveguide 12 is devoid of IRIS between the asymmetric chamber 32 and the sub-chamber 44 of the symmetrical chamber 28 which is adjacent to the asymmetrical chamber 32.

In the example illustrated in FIG. 1, the first lateral boundary 34 of the asymmetrical chamber 32 comprises, along the axis of propagation X-X, a diverging portion 52 and a convergent portion 54.

By "divergent" is meant that the diverging portion 52 extends non-parallel to the X-X propagation axis, regardless of whether it extends towards or away from the X-X propagation axis.

By "convergent" is meant that if the diverging portion 52 extends towards the X-X propagation axis, the convergent portion 54 then extends opposite the propagation axis X-X, and vice versa.

The first lateral border 34 also comprises, in the example of FIG. 1, a rectilinear part 56, parallel to the propagation axis XX, and extending between the divergent part 52 and the convergent part 54. In addition, the first lateral boundary 34 comprises in particular an auxiliary rectilinear portion 58, parallel to the axis of propagation XX, and extending from the convergent portion 54. In the example of FIG. 1, the convergent portion 54 has a length such that the auxiliary rectilinear portion 58 is aligned with the adjacent lateral boundary 30 of the first lateral boundary 34.

More specifically, in the example of FIG. 1, the first lateral border 34 protrudes away from the second lateral border 36 in the transverse direction Y-Y from its adjacent lateral border 30.

The divergent portion 52 thus extends from an upstream portion of the adjacent lateral boundary 30 of the first lateral boundary 34 to the opposite of the second lateral boundary 36 of the asymmetric chamber 32.

On the contrary, the convergent portion 54 extends, from the rectilinear portion 56, towards the second lateral boundary 36 of the asymmetrical chamber 32.

The first lateral border 34 is disposed outside the internal cavity 38 and is partly away from the first lateral edge 40A of the central layer 18. In other words, the diverging portion 52 extends in the central layer 18 opposite the first side edge 40A.

The maximum distance between the first lateral edge 40A and the first lateral border 34, in the transverse direction Y-Y, is, for example, greater than 0.25 mm.

In the example of FIG. 1, each of the diverging portion 52 and the convergent portion 54 here has, in projection on a plane orthogonal to the plane of symmetry, a predetermined profile in the form of a straight line.

In projection on said orthogonal plane, each of the diverging portion 52 and the convergent portion 54 respectively extends, at a connection point 60A, 60B, from the upstream portion of the adjacent lateral boundary 30 or the rectilinear part 56.

Each of the diverging portion 52 and the convergent portion 54 then respectively has a tangent at this point of connection 60A, 60B forming an angle with the upstream portion or the straight portion 56 greater than 0 °.

As illustrated in FIG. 1, the second lateral border 36 is aligned with its adjacent lateral border 30. In particular, the second lateral boundary line 36 is therefore here parallel to the propagation axis XX and runs along the second lateral edge 40B of the layer Central 18.

In the asymmetrical chamber 32, the length of the rectilinear portion 56 and the maximum distance between the first lateral boundary 34 and the first lateral edge 40A in the transverse direction YY influence the second predetermined frequency rejected by the waveguide 12. Indeed, when an electromagnetic wave having a wavelength greater than or equal to the predetermined minimum wavelength propagates in the asymmetric chamber 32, it decomposes, thanks to the asymmetry, into at least a first mode. propagation principal and a second main propagation mode each having a different propagation constant.

As explained below, these two modes generate by coupling the rejection of the second predetermined frequency f2.

A variation in the length of the rectilinear part 56 modifies a phase difference between the two modes.

In addition, a variation of the maximum distance between the first lateral border

34 and the first lateral edge 40A in the transverse direction Y-Y changes the propagation constant of one of the modes and very little the propagation constant of the other mode.

In addition, a variation in the maximum distance between the first lateral edge 40A and the second lateral edge 40B in the transverse direction Y-Y changes the propagation constants of the two modes.

Thus, the length of the rectilinear part 56 and the maximum distance between the first lateral border 34 and the first lateral edge 40A in the transverse direction YY are determined, so that, when the two modes have the second predetermined frequency, the two modes are in phase opposition at the output of the waveguide 12.

In this way, an electromagnetic wave having the second predetermined frequency has a very large attenuation at the output of the waveguide 12. The waveguide 12 thus allows to reject the second predetermined frequency.

Figures 3 and 4 illustrate simulation comparisons between the first embodiment of the component described above and a component as described above but without an asymmetric chamber 32.

In FIG. 3, the curves in solid lines correspond to a simulation for a component devoid of asymmetric chamber 32, and the curves in dashed lines correspond to a simulation for a component according to the first embodiment in which the maximum distance between the first lateral border 34 and the first lateral edge 40A, in the transverse direction YY, is equal to 1.25 mm.

The curves designated S1, 1 correspond to the reflection coefficient of the waveguide 12 as a function of the frequency, and the curves designated S2,1 correspond to the direct transmission coefficient as a function of the frequency.

In FIG. 4, the curves in solid lines correspond to a simulation for a component devoid of asymmetric chamber 32; and curves in broken lines correspond to a simulation for a component according to the first embodiment in which the maximum distance between the first lateral border 34 and the first lateral edge 40A, in the transverse direction YY, is equal to 1.1 mm.

With regard to these two figures, the addition of the asymmetric chamber 32 thus makes it possible to ensure a rejection of the second predetermined frequency f2 located above and close to the bandwidth of the component.

The comparison of FIGS. 3 and 4 also demonstrates that the maximum distance between the first lateral border 34 and the first lateral edge 40A in the transverse direction Y-Y makes it possible to vary the value of the second predetermined frequency rejected by the waveguide 12.

A second embodiment of the microwave component 10 according to the invention is illustrated in FIG. 5. In this figure, only the asymmetrical chamber 32 is shown.

This embodiment differs from the first embodiment of FIG. 1 in that the first lateral border 34 is aligned with the adjacent lateral border 30. In addition, the second lateral border 36 is similar to the first lateral border 34 of the first mode. of realization.

The second lateral boundary 36 in fact comprises a diverging portion 62, a convergent portion 64, and a rectilinear portion 66, parallel to the propagation axis X-X, and extending between the divergent portion 62 and the convergent portion 64.

The second lateral border 36 protrudes away from the first lateral border 34 in the transverse direction Y-Y from its adjacent lateral boundary 30.

The diverging portion 62 thus extends, at a connection point 60A, from an upstream portion of the adjacent lateral boundary 30 of the second lateral boundary 36, opposite the first lateral boundary 34. On the contrary, the convergent portion 64 extends, at a connection point 60B, from the rectilinear portion 66, towards the first lateral border 34.

A third embodiment of the microwave component 10 according to the invention is illustrated in FIG.

This embodiment differs from the first embodiment of FIG. 1 in that, in the asymmetrical chamber 32, the lateral edges 40A, 40B of the central layer 18 are not symmetrical with respect to the plane of symmetry.

The second lateral edge 40B of the central layer 18 in fact comprises a diverging edge 68, a convergent edge 70, and a rectilinear edge 72 parallel to the propagation axis XX, and extending between the diverging edge 68 and the convergent edge 70. The diverging edge 68 extends in this example, in the XY plane, from an upstream portion of the second lateral edge 40B, to the first lateral boundary 34 of the asymmetric chamber 32. On the contrary, the convergent edge 70 is extends, from the straight edge 72, in the XY plane, opposite the first lateral boundary 34 of the asymmetric chamber 32.

In other words, the second lateral edge 40B forms a projection towards the second lateral border 36, in the XY plane.

In addition, the diverging edge 68, the convergent edge 70, and the straight edge 72 extend here along the axis ZZ from the upper surface 20B of the lower layer 16 to the lower surface 21A of the upper layer 14. In a variant not shown, the diverging edge 68, the convergent edge 70, and / or the straight edge 72 extend along the axis ZZ from the upper surface 20B of the lower layer 16 to a border greater than the deviation along the axis ZZ of the lower surface 21 A of the upper layer 16.

In addition, the diverging edge 68 and the convergent edge 70 extend here substantially parallel to the Z-Z axis. In variant not shown, at least one of the diverging edge 68 and the convergent edge 70 has an inclination with the Z-Z axis.

As in the first embodiment, the first lateral edge 40A is parallel to the X-X propagation axis.

A fourth embodiment of the microwave component 10 according to the invention is illustrated in FIG. 7.

This embodiment differs from the first embodiment of FIG. 1, in that the first lateral edge 40A and the second lateral edge 40B run along all their respective lengths, the first lateral border 34 and the second lateral border 36 respectively.

In particular, the first lateral edge 40A comprises a diverging edge 74, a convergent edge 76, and a rectilinear edge 78 parallel to the axis of propagation X-X, and extending between the diverging edge 74 and the convergent edge 76.

The diverging edge 74 extends in this example, from an upstream portion of the first lateral edge 40A, opposite the second lateral boundary 36 of the asymmetrical chamber 32. On the contrary, the convergent edge 76 extends from rectilinear edge 78 to second lateral boundary 36 of asymmetrical chamber 32.

The diverging edge 74, the convergent edge 76, and the straight edge 78 of the first lateral edge 40A extends along all their respective lengths, the diverging portion 52, the convergent portion 54 and the straight portion 56 of the first lateral boundary 34 respectively. In other words, the first lateral edge 40A forms a hollow in the central layer 18 in the XY plane.

In this fourth embodiment, the waveguide 12 further comprises a dielectric portion 80 disposed in the internal cavity 38.

The dielectric portion 80 is in contact with the first lateral edge 40A.

It is received in a spacing 82 delimited by the diverging edge 74, the convergent edge 76, and the straight edge 78 of the first lateral edge 40A.

The dielectric portion 80 has a border 84 opposite the second lateral border 36. The edge 84 is here parallel to the axis of propagation X-X and aligned with a lateral edge of the central layer 18 of the symmetrical chamber 28.

The dielectric portion 80 has a third dielectric constant. The third dielectric constant is strictly less than the first dielectric constant.

A fifth embodiment of the microwave component 10 according to the invention is illustrated in FIG. 8.

This embodiment differs from the first embodiment of FIG. 1 in that, in the asymmetrical chamber 32, the lateral edges 40A, 40B are not symmetrical with respect to the plane of symmetry.

The first lateral edge 40A in fact comprises a diverging edge 74, a convergent edge 76, and a rectilinear edge 78 parallel to the propagation axis X-X, and extending between the diverging edge 74 and the convergent edge 76.

In other words, the first lateral edge 40A forms a hollow in the central layer 18 in the XY plane.

The diverging edge 74 runs along part of the diverging portion 52 of the first lateral boundary 34 and the convergent edge 76 runs along a portion of the convergent portion 54 of the first lateral boundary 34.

The rectilinear edge 78 is disposed, in the transverse direction Y-Y, between the first lateral border 34 and the second lateral border 36, away from the first lateral border 34.

A sixth embodiment of the microwave component 10 according to the invention is illustrated in FIG. 9. This embodiment differs from the embodiment of FIG. 8 in that the first lateral edge 40A forms a projection towards the second lateral border 36, instead of a hollow in the central layer 18, in the XY plane.

The diverging edge 74 of the first lateral edge 40A extends, from an upstream portion of the first lateral edge 40A, towards the second lateral boundary 36 of the asymmetrical chamber 32. On the contrary, the convergent edge 76 extends, at from the straight edge 78, opposite the second lateral boundary 36 of the asymmetric chamber 32.

A seventh embodiment of the microwave component 10 according to the invention is illustrated in FIG.

This embodiment differs from the embodiment of FIG. 9 at the level of the second lateral boundary 36 of the asymmetric chamber 32 and the second lateral edge 40B.

As in the second embodiment illustrated in FIG. 5, the second lateral boundary 36 comprises a diverging portion 62, a convergent portion 64, and a rectilinear portion 66, parallel to the axis of propagation XX, and extending between the divergent part 62 and convergent part 64.

More precisely, the second lateral border 36 protrudes away from the first lateral border 34 in the transverse Y-Y direction from the adjacent lateral border 30.

The diverging portion 62 of the second lateral boundary 36 thus extends, at a connection point 60A, from an upstream portion of the adjacent lateral boundary 30 of the second lateral boundary 36, as opposed to the first lateral border 34.

In contrast, the converging portion 64 of the second lateral boundary 36 extends at a connection point 60B from the rectilinear portion 66 of the second lateral boundary 36 to the first lateral boundary 34.

The connection point 60A of the diverging portion 62 of the second lateral boundary 36 is here aligned in the transverse direction YY with the connection point 60A of the diverging portion 52 of the first lateral boundary 34. As a variant, these connection points 60A are arranged, in projection on the axis of propagation XX, at different positions, that is to say are not aligned in the direction YY.

Similarly, the connection point 60B of the convergent portion 64 of the second lateral boundary line 36 is here aligned in the transverse direction YY with the connection point 60B of the convergent portion 54 of the first lateral boundary 34. As a variant, these points link 60B are arranged along the axis of propagation XX at different positions. Furthermore, in this seventh embodiment, the second lateral edge 40B comprises a diverging edge 68, a convergent edge 70, and a straight edge 72 parallel to the axis of propagation XX, and extending between the diverging edge 68 and the convergent edge 70 of the second lateral edge 40B.

The diverging edge 68 of the second lateral edge 40B extends in this example, from an upstream portion of the second lateral edge 40B, opposite the first lateral edge 34. On the contrary, the convergent edge 70 of the second edge Lateral 40B extends from the straight edge 72 of the second lateral edge 40B to the first lateral boundary 34.

In other words, the second lateral edge 40B forms a hollow in the central layer 18 in the XY plane.

The diverging edge 68 of the second lateral edge 40B runs along part of the diverging portion 62 of the second lateral boundary 36 and the convergent edge 70 runs along a portion of the convergent portion 64 of the second lateral boundary 36.

The rectilinear edge 72 of the second lateral edge 40B is disposed, along the transverse Y-Y direction, between the second lateral border 36 and the first lateral border 34, away from the second lateral border 36.

An eighth embodiment of the microwave component 10 according to the invention is illustrated in FIG.

This embodiment differs from the third embodiment of FIG. 6 at the level of the first lateral border 34.

The first lateral border 34 projects towards the second lateral border 36 along an axis transverse to the X-X propagation axis from the adjacent lateral border 30.

The divergent portion 52 of the first lateral boundary 34 thus extends, from an upstream portion of the adjacent lateral boundary 30 of the first lateral boundary 34, to the second lateral boundary 36.

On the contrary, the convergent portion 54 of the first lateral border 34 extends, from the rectilinear portion 56, opposite the second lateral border 36.

Furthermore, in this eighth embodiment, the first lateral edge 40A comprises a diverging edge 74, a convergent edge 76, and a straight edge 78 parallel to the axis of propagation XX, and extending between the diverging edge 74 and the convergent edge 76.

The diverging edge 74, the convergent edge 76 and the straight edge 78 of the first lateral edge 40A here follow respectively the diverging portion 52, the convergent portion 54 and the rectilinear portion 56 of the first lateral boundary 34. In this eighth embodiment, the distance variation between the first lateral border 34 and the second lateral edge 40B in the transverse direction Y-Y changes the propagation constant of one of the propagation modes.

A ninth embodiment of the microwave component 10 according to the invention is illustrated in FIG.

This embodiment differs from the eighth embodiment of FIG. 11 at the level of the first lateral edge 40A and the second lateral edge 40B.

The second lateral edge 40B runs along the second lateral boundary 36 and is in particular parallel to the X-X propagation axis along its entire length.

In addition, the first lateral edge 40A protrudes from the first lateral border 34 towards the second lateral border 36.

More precisely, the rectilinear edge 78 of the first lateral edge 40A is disposed along the transverse direction YY between the first lateral border 34 and the second lateral border 36, away from the first lateral border 34, the diverging edge 74 and the convergent edge 76 of the first lateral edge 40A respectively along the divergent portion 52 and the convergent portion 54 of the first lateral boundary 34.

A tenth embodiment of the microwave component 10 according to the invention is illustrated in FIG. 13.

This embodiment differs from the embodiment of FIG. 12 in that the diverging edge 74 and the convergent edge 76 of the first lateral edge 40A do not respectively run along the divergent portion 52 and the convergent portion 54 of the first lateral boundary 34.

An eleventh embodiment of the microwave component 10 according to the invention is illustrated in FIG.

This embodiment differs from the embodiment of FIG. 1 in that the predetermined profile of the diverging portion 52 and the convergent portion 54 of the first lateral boundary 34 is an exponential profile.

In another variant of this eleventh embodiment, not shown, said predetermined profile is a sinusoidal profile.

In yet another variant of this eleventh embodiment, not shown, said predetermined profile is a so-called Klopfenstein profile.

In another non-illustrated variant of the first embodiment and the eleventh embodiment, the predetermined profile is different for the divergent portion 52 and for the convergent portion 54 of the first lateral boundary 34.

In variant not shown, the first lateral border 34 protrudes away from the second lateral border 36 in the transverse direction YY from its border adjacent lateral 30, and the second lateral border 36 projects towards the first lateral border 34 in the transverse direction YY from its adjacent lateral border 30.

In a variant of the preceding embodiments, the first lateral border 34 has no rectilinear portion extending between the divergent portion 52 and the convergent portion 54. The convergent portion 54 and the divergent portion 52 of the first boundary then join.

As a variant of the preceding embodiments, the upper layer 14 and / or the lower layer 16 is (are) formed by a one-piece layer made of electrically conductive material.

In yet another variant of the preceding embodiments, illustrated in FIG. 15, the upper layer 14 and the lower layer 16 are formed by a one-piece layer made of electrically conductive material, and the central layer 18 is formed by a dielectric layer. monobloc material coming, the central layer 18 having the first dielectric constant.

The waveguide 12 is then of "integrated in the substrate" type, the upper layer 14, the lower layer 16 and the central layer 18 together forming a substrate.

The central layer 18 then defines a plurality of through holes 86 arranged between the lateral boundaries 34, 36 of the asymmetric chamber 32.

Each through hole 86 is devoid of electrically conductive coating.

The portion of the central layer 18, delimited laterally by the lateral boundaries 34, 36 of the asymmetrical chamber 32, thus has a fourth equivalent dielectric constant lower than the first dielectric constant.

As a variant of the previous embodiments, illustrated in FIG. 16, the waveguide 12 is of the "metal waveguide" type.

The waveguide 12 comprises an upper layer 14, a lower layer 16 and electrically conductive lateral walls 88, for example made of metal.

The side walls 88 define an internal cavity 38, a central dielectric layer 18 being disposed in the internal cavity 38 in contact with one of the side walls 88.

In another variant, the component 10 is a multiplexer. The component 10 then comprises another asymmetrical chamber similar to the asymmetric chamber 32 of one of the embodiments described above. The two asymmetric chambers are then arranged at the inlet 13A and at the exit 13B of the waveguide 12.

The embodiments described above can be combined in any technically possible combination. Thanks to the characteristics described above, the microwave component 10 is simple and provides a filtering function of an electromagnetic wave with good off-band rejection while being compact and low cost. The design time of such a component is further reduced.

Claims

1. - Microwave component (10) comprising a waveguide (12) comprising at least one upper layer (14) having an electrically conductive lower surface, a lower layer (16) having an electrically conductive upper surface, and a central layer (18) defining a propagation zone (19) of an electromagnetic wave, the propagation zone (19) extending along an axis of propagation (XX),

the propagation zone (19) comprising at least one symmetrical propagation chamber (28) delimited by the lower surface of the upper layer (14), the upper surface of the lower layer (16) and two spaced symmetrical lateral boundaries, the boundaries side of the symmetrical chamber (28) being adapted to prevent the passage of an electromagnetic wave having a wavelength greater than or equal to a predetermined minimum wavelength,

the lateral boundaries of the symmetrical chamber (28) having a plane of symmetry parallel to the axis of propagation (XX) and orthogonal to the lower surface of the upper layer (14) and to the upper surface of the lower layer (16) ,

characterized in that the propagation zone (19) further comprises an asymmetric propagation chamber (32) delimited by the lower surface of the upper layer (14), the upper surface of the lower layer (16) and two spaced lateral boundaries (34, 36) adapted to prevent the passage of an electromagnetic wave having a wavelength greater than or equal to the predetermined minimum wavelength,

the lateral boundaries (34, 36) of the asymmetric chamber (32) being devoid of symmetry with respect to any plane parallel to said plane of symmetry,

the central layer (18) being at least partly made of a dielectric material, and the propagation zone (19) comprising an internal cavity (38) delimited by the lower surface of the upper layer (14), the upper surface of the lower layer (16) and lateral edges (40A, 40B) of the central layer (18), the lateral boundaries (34, 36) of the asymmetric chamber (32) being disposed outside the internal cavity (38).

2. - Component according to claim 1, wherein each lateral border (34, 36) of the asymmetrical chamber (32) is connected to an adjacent lateral border (30) of the symmetrical chamber (28).

3. - Component according to claim 2, wherein at least one of the lateral boundaries (34, 36) of the asymmetric chamber (32) protrudes from the adjacent lateral border (30) away from the other side boundaries (34, 36) of the asymmetrical chamber (32) in a direction (Y-Y) transverse to the axis of propagation (XX).

4. - Component according to any one of claims 2 or 3, wherein at least one of the lateral boundaries (34, 36) of the asymmetrical chamber (32) projects towards the other of the lateral boundaries (34, 36) of the asymmetric chamber (32) in a transverse direction (Y-Y) to the axis of propagation (XX) from the adjacent lateral boundary (30).

5. - Component according to any one of claims 2 to 4, wherein at least one of the lateral boundaries (34, 36) of the asymmetrical chamber (32) is aligned with said adjacent lateral border (30).

6. Component according to any one of claims 2 to 5, wherein at least a first of the lateral boundaries (34, 36) of the asymmetric chamber (32) comprises a diverging portion (52, 62).

The component of claim 6, wherein said first lateral boundary (34, 36) further comprises a converging portion (54, 64).

8. - Component according to any one of claims 6 or 7, wherein the diverging portion (52, 62) and / or the convergent portion (54, 64) has (s), in projection on a plane orthogonal to said plane of symmetry, a predetermined profile selected from: a straight line, an exponential profile, a sinusoidal profile, a profile called Klopfenstein.

9. - Component according to any one of claims 6 to 8, wherein said first lateral boundary (34, 36) further comprises a rectilinear portion (56, 66), parallel to the axis of propagation (X-X).

10. - Component according to any one of claims 1 to 9, wherein at least one of said side boundaries (34, 36) of the asymmetrical chamber (32) comprises a row of vias, arranged through the central layer (18) , the spacing between two successive vias of the row being less than the predetermined minimum wavelength, for example less than or equal to one fifth of the determined minimum wavelength.

1 1. The component of any one of claims 1 to 10, wherein at least one of said side boundaries (34, 36) of the asymmetric chamber (32) comprises an electrically conductive plate.

12. - Component according to any one of claims 1 to 1 1, wherein one of the lateral edges (40A, 40B) of the central layer (18) disposed in the asymmetric chamber (32) projects towards the other lateral edge of the central layer (18) in a direction transverse to the axis of propagation (XX).

13. - Component according to any one of claims 1 to 12, wherein in the asymmetrical chamber (32), the maximum distance between one of the lateral edges (40A, 40B) of the cavity and the lateral border (34, 36 ) closest to said lateral edge, along an axis orthogonal to the axis of propagation (XX), is greater than 0.25 mm.

14. - Component according to any one of claims 1 to 13, wherein the asymmetrical chamber (32) is disposed at one end of the propagation zone (19), along the axis of propagation (X-X).