Integration of high-frequency components in flexible waveguides

Abstract

The invention relates to embodiments of a flexible waveguide [for example for guiding at least one high-frequency signal, for example having a frequency of greater than or equal to 0 Hz], comprising the following features: a first metal coating [for example a first shielding metal coating]; a second metal coating [for example a second shielding metal coating]; a flexible substrate which is disposed between the first metal coating and the second metal coating; and at least one high-frequency component which is embedded in the substrate and is connected to at least one center conductor [for example inner conductor] of the flexible waveguide.

Description

[0001] Integration of high-frequency components into flexible waveguides

[0002] Description

[0003] Embodiments of the present invention relate to the integration of at least one radio-frequency component into a flexible waveguide. Some embodiments relate to the integration of RF components into flexible waveguides.

[0004] Quantum computers with superconducting qubits require numerous RF interconnect lines. Depending on their function (readout lines, control lines, etc.), these lines must be equipped with RF components such as attenuators, low-pass filters, and bandpass filters.

[0005] In cryogenic applications, such as quantum computers with superconducting qubits, commercially available coaxial waveguides are currently used to transmit RF signals [1]. So far, so-called semi-rigid coaxial cables with connectors have been used. Typically, the components are screwed into the cables with coaxial connectors. One example is the attenuators distributed at different temperature levels on the signal lines.

[0006] Furthermore, flexible multi-core cables with superconducting inner conductors are known from [2]. Furthermore, a microstrip line with an integrated stepped-impedance low-pass filter is known from [3]. However, these can only be used at cryogenic temperatures and, due to the high attenuation at room temperature, are unsuitable for connecting to signal generators and / or signal analyzers operating at room temperature in cryogenic applications.

[0007] The present invention is therefore based on the object of creating a concept which makes it possible to reduce the space required for the cables and / or to improve signal quality.

[0008] This problem is solved by the independent patent claims.

[0009] Advantageous further developments can be found in the dependent patent claims. Embodiments provide a flexible waveguide [e.g., for guiding at least one high-frequency signal, e.g., with a frequency greater than or equal to 0 Hz], having the following features: a first metallization [e.g., first shielding metallization], a second metallization [e.g., second shielding metallization], a flexible substrate arranged between the first metallization and the second metallization, and at least one high-frequency component embedded in the substrate and connected to at least one center conductor [e.g., inner conductor] of the flexible waveguide.

[0010] In embodiments, the flexible waveguide can be designed as a ribbon cable.

[0011] In embodiments, the at least one high-frequency component is at least two high-frequency components, wherein the at least two high-frequency components are arranged offset from one another.

[0012] In embodiments, an offset arrangement of the at least two high-frequency components refers to the geometric centers of the at least two high-frequency components being arranged at different positions along the wave propagation direction of the flexible waveguide and / or perpendicular to the wave propagation direction. For example, with three or more high-frequency components, the geometric centers of the high-frequency components can lie on a straight line that runs parallel to the wave propagation direction of the flexible waveguide and / or on a straight line that runs perpendicular to the wave propagation direction of the flexible waveguide.

[0013] In embodiments, the at least two high-frequency components are arranged offset from one another in the wave propagation direction of the flexible waveguide and / or perpendicular to the wave propagation direction.

[0014] In embodiments, the at least two high-frequency components are at least three high-frequency components, wherein the at least three high-frequency components are arranged offset from one another according to a regular pattern, or wherein the at least three high-frequency components are arranged offset from one another according to a non-regular pattern [eg random].

[0015] For example, the regular pattern can be a regular checkerboard pattern with a predefined number of steps running along and / or perpendicular to the wave propagation, such as 3x1, 3x2, 3x3, etc. Cascading is also possible, ie several regular checkerboard patterns, each with an identical / different configuration.

[0016] For example, the non-regular pattern may be determined by means of a random number generator, or in other words, positions of the high-frequency components may be determined by means of a random number generator.

[0017] In embodiments, at least two center conductors [e.g., inner conductors] are embedded in the flexible substrate, wherein the at least two high-frequency components are each connected to a center conductor.

[0018] In other words, the flexible waveguide may have a plurality of center conductors, each high-frequency component being connected to a center conductor.

[0019] In embodiments, the at least one high-frequency component is at least two high-frequency components, wherein the at least two high-frequency components are arranged in series with each other [ie, are electrically connected in series via the center conductor].

[0020] In embodiments, a [e.g., first] high-frequency component of the at least one high-frequency component is a filter.

[0021] In embodiments, the high-frequency component has at least one stub line connected at a first end to the at least one center conductor.

[0022] In embodiments, the at least one stub line is open at a second end.

[0023] In embodiments, the at least one stub line is terminated at the second end.

[0024] In embodiments, the at least one stub line is terminated at the second end by at least one via connected to the first metallization and / or second metallization.

[0025] In some embodiments, at least one section of the at least one stub line runs parallel to the at least one center conductor. In some embodiments, at least one section of the at least one stub line has a meandering or polygonal shape.

[0026] In embodiments, a [e.g., second] high-frequency component of the at least one high-frequency component is an attenuator.

[0027] In embodiments, the at least one center conductor comprises a first center conductor and a second center conductor, wherein the attenuator is connected in series between the first center conductor [e.g., a first end of the first center conductor] and the second center conductor [e.g., a second end of the second center conductor].

[0028] In embodiments, the attenuator comprises at least a first resistive element and a second resistive element, wherein the first resistive element is connected in series between the first center conductor and the second center conductor, wherein the second resistive element is connected in series between the first center conductor and a first via that is [e.g., electrically] connected to the first metallization and / or second metallization.

[0029] In embodiments, the attenuator comprises a third resistive element, wherein the third resistive element is connected in series between the first center conductor and a second via that is [e.g., electrically] connected to the first metallization and / or second metallization.

[0030] In embodiments, the attenuator comprises a fourth resistive element and a fifth resistive element, wherein the fourth resistive element is connected between the second center conductor and a third via that is electrically connected to the first metallization and / or second metallization, wherein the fifth resistive element is connected between the second center conductor and a fourth via that is electrically connected to the first metallization and / or second metallization.

[0031] In embodiments, the resistive elements are each implemented by a stripline having a higher insertion loss [e.g. with the same matching] than the first center conductor and / or the second center conductor [e.g. by lossy materials [e.g. titanium-tungsten alloy] and / or by a smaller cross-section],

[0032] In embodiments, the striplines are connected to the first center conductor and / or the second center conductor. In embodiments, a [e.g., third] radio-frequency component of the at least one radio-frequency component is a directional coupler.

[0033] In embodiments, the directional coupler has two striplines coupled to one another.

[0034] In embodiments, the two coupled strip lines run parallel to each other in the flexible substrate.

[0035] In embodiments, the two coupled striplines are arranged in different planes in the flexible substrate.

[0036] For example, the two striplines coupled to one another can be arranged one above the other in the flexible substrate [e.g. with respect to a straight line perpendicular to the first metallization and / or second metallization].

[0037] In embodiments, the two striplines coupled to one another have a [e.g. the same] meander-shaped or polygon-shaped course at least in one coupled section.

[0038] In embodiments, the two coupled striplines are arranged in the same plane in the flexible substrate.

[0039] For example, the two striplines coupled to each other can be arranged next to each other in the flexible substrate [e.g. with respect to a straight line running parallel to the first metallization and / or second metallization].

[0040] In embodiments, the two striplines coupled to one another have corresponding sawtooth shapes at least in one coupled section.

[0041] In embodiments, a first stripline of the two coupled striplines is connected to at least a first center conductor of the at least one center conductor, and a second stripline of the two coupled striplines is connected to at least a second center conductor of the at least one center conductor. In embodiments, each of the two coupled striplines is connected to at least one center conductor.

[0042] In embodiments, a [e.g., fourth] high-frequency component of the at least one high-frequency component is a transformer.

[0043] In embodiments, the transformer comprises a first loop-shaped stripline and a second loop-shaped stripline.

[0044] In embodiments, the first loop-shaped stripline and the second loop-shaped stripline are arranged in different planes of the flexible substrate.

[0045] For example, the two loop-shaped striplines can be arranged one above the other in the flexible substrate [e.g. with respect to a straight line perpendicular to the first metallization and / or second metallization].

[0046] In embodiments, the first loop-shaped stripline is connected to a first center conductor of the at least one center conductor, wherein the second loop-shaped stripline is connected to a second center conductor of the at least one center conductor.

[0047] In embodiments, the first loop-shaped stripline is connected in series between the first center conductor and a first via connected to the first metallization and / or second metallization, wherein the second loop-shaped stripline is connected in series between the second center conductor and a second via connected to the first metallization and / or second metallization.

[0048] In embodiments, a [e.g., fifth] high-frequency component of the at least one high-frequency component is a power divider.

[0049] In embodiments, the power divider is implemented using stripline technology.

[0050] In embodiments, the power splitter is connected on the input side to a first center conductor of the at least one center conductor, and the power splitter is connected on the output side to a second center conductor and a third center conductor of the at least one center conductor. In embodiments, the power splitter comprises a stripline, a first end of the stripline being connected to the first center conductor, and a second end of the stripline being connected to the second center conductor and the third center conductor.

[0051] In embodiments, the stripline has a length that is one quarter of a wavelength of a signal carried in the first center conductor.

[0052] In embodiments, the stripline has a line characteristic impedance which is equal to a quotient of a line characteristic impedance ZO and the square root of two.

[0053] In embodiments, the power divider comprises a first stripline and a second stripline, wherein the first stripline is connected in series between the first center conductor and the second center conductor, and wherein the second stripline is connected in series between the first center conductor and the third center conductor.

[0054] In embodiments, the first stripline and the second stripline each have a length that is one quarter of a wavelength of a signal carried in the first center conductor.

[0055] In embodiments, the first stripline and the second stripline each have a line characteristic impedance that is equal to a product of a line characteristic impedance ZO and the square root of two.

[0056] In embodiments, the power divider comprises a first [e.g., semicircular] stripline and a second [e.g., semicircular] stripline [e.g., mirrored to the first semicircular stripline], wherein the first stripline is connected in series between the first center conductor and the second center conductor, and wherein the second stripline is connected in series between the first center conductor and the third center conductor.

[0057] In some embodiments, the first stripline and the second stripline are connected on the output side via a resistor implemented using stripline technology (e.g., of size 2Z0). In some embodiments, the first stripline and the second stripline each have a length that is one-quarter of a wavelength of a signal carried in the first center conductor.

[0058] In embodiments, the first stripline and the second stripline each have a line characteristic impedance that is equal to a product of a line characteristic impedance Z0 and the square root of two.

[0059] Further embodiments provide a quantum computer having the following features: a quantum processor, a signal generator and / or signal evaluator, and at least one flexible waveguide according to one of the embodiments described herein for signal transmission between the quantum processor and the signal generator and / or signal evaluator.

[0060] In embodiments, the quantum processor is configured to operate at a cryogenic temperature [e.g., a temperature of less than 1 K].

[0061] In embodiments, the signal generator and / or signal evaluator is configured to operate at a cryogenic temperature [e.g., a temperature of less than 1 K] or a non-cryogenic temperature [e.g., a temperature of more than 253 K].

[0062] Further embodiments provide a method for producing a flexible waveguide. The method comprises a step of providing a first layer of a flexible substrate. The method further comprises a step of providing at least one center conductor and at least one high-frequency component on the first layer of the flexible substrate. The method further comprises a step of providing a second layer of the flexible substrate on the first layer of the flexible substrate and the center conductor with the high-frequency component, such that the at least one center conductor and the at least one high-frequency component are embedded between the first layer of the flexible substrate and the second layer of the flexible substrate.The method further comprises a step of providing a first metallization and a second metallization, wherein the first metallization is provided on a first side of a stack comprising the first layer of the flexible substrate and the second layer of the flexible substrate, and wherein the second metallization is provided on a second side of the stack opposite the first side. Further embodiments provide a method for producing a flexible waveguide with at least one integrated radio-frequency component. The method further comprises a step of providing a first layer of a flexible substrate of the flexible waveguide. The method further comprises a step of forming at least one hole through the first layer of the flexible substrate. The method further comprises a step of coating both sides [e.g.by sputtering, thermal vapor deposition, or electroplating] of the first layer of the flexible substrate with a first metallization, wherein during the double-sided coating, side walls of the at least one hole are coated with the first metallization in order to obtain at least one via. The method further comprises a step of structuring [e.g. by a combination of photolithography and etching [e.g. wet chemical and / or plasma-assisted] the first metallization in order to obtain, on a first side of the first layer of the flexible substrate, a center conductor of the flexible waveguide and at least one stripline of the radio-frequency component connected to the center conductor. The method further comprises a step of providing a second layer of the flexible substrate on the first side of the first layer of the flexible substrate.The method further comprises a step of forming a plurality of holes through the first layer and the second layer of the flexible substrate. The method further comprises a step of coating the flexible substrate on both sides with a second metallization, wherein, during the double-sided coating, sidewalls of the plurality of holes are coated with the second metallization to obtain a plurality of vias. The method further comprises a step of structuring the second metallization to obtain a first shielding metallization of the flexible waveguide.

[0063] In embodiments, the plurality of vias may be arranged such that the plurality of vias surround the center conductor and the high frequency component.

[0064] Embodiments provide a flexible waveguide [e.g. for guiding at least one high-frequency signal, e.g. with a frequency greater than or equal to 0 Hz], having the following features: a first metallization [e.g. first shielding metallization], a second metallization [e.g. second shielding metallization], a flexible substrate arranged between the first metallization and the second metallization, and a center conductor [e.g. inner conductor] embedded in the flexible substrate, wherein the center conductor comprises at least two striplines, wherein at least one stripline of the at least two striplines comprises a superconducting material. For example, the flexible waveguide can be designed as a ribbon cable. In particular, the flexible waveguide can have a plurality / multiplicity of center conductors.

[0065] In embodiments, a first stripline of the at least two striplines comprises a first superconducting material, wherein a second stripline of the at least two striplines comprises a second superconducting material.

[0066] In embodiments, the first superconducting material and the second superconducting material are two different materials.

[0067] In embodiments, a first stripline of the at least two striplines comprises a superconducting material, wherein a second stripline of the at least two striplines comprises a non-superconducting material.

[0068] In embodiments, the non-superconducting material does not exhibit superconducting properties at any temperature.

[0069] In embodiments, the superconducting material exhibits superconducting properties at temperatures below a material-specific transition temperature.

[0070] In embodiments, the superconducting material may be one of the following materials: niobium, aluminum, lead, indium, zinc, tantalum, or niobium nitride.

[0071] In embodiments, the non-superconducting material may be one of the following materials: copper, nickel, gold, or silver.

[0072] In embodiments, the at least two strip lines run parallel [e.g., with a constant distance] to each other.

[0073] In embodiments, the at least two strip lines are connected to each other [e.g., mechanically and / or electrically].

[0074] In embodiments, the at least two striplines are directly [mechanically and / or electrically] connected to one another [ie, without an adhesion layer and / or without a diffusion barrier]. In embodiments, at least two striplines are [mechanically and / or electrically] connected to one another by means of an adhesion layer [e.g., titanium (Ti), titanium-tungsten (Ti-W), chromium (Cr)] and / or by means of a diffusion barrier [e.g., titanium dioxide (TiO2) or titanium nitride (TiN)].

[0075] For example, stacking two metal layers typically does not require an adhesion layer between the metal layers, as metal-to-metal adhesion provides good adhesion. However, for some metal combinations, a diffusion barrier [e.g., titanium dioxide (TiO2) or titanium nitride (TiN)] is required between them to prevent the formation of an alloy between the two metals.

[0076] In embodiments, the metal of the center conductor and / or the first metallization and / or the second metallization can be bonded to the substrate [e.g., polymer substrate] by means of an adhesion layer [e.g., titanium (Ti), titanium-tungsten (Ti-W), chromium (Cr), ...]. Depending on the metal, however, the adhesion layer may also be omitted.

[0077] In embodiments, a third stripline of the at least two striplines comprises a superconducting material, wherein the second stripline is arranged between the first stripline and the third stripline.

[0078] For example, the first stripline may comprise copper, the second stripline may comprise niobium, and the third stripline may comprise copper.

[0079] In embodiments, a third stripline of the at least two striplines comprises a non-superconducting material, wherein the first stripline is arranged between the second stripline and the third stripline.

[0080] For example, the second stripline may comprise niobium, the first stripline may comprise copper, and the third stripline may comprise niobium.

[0081] In embodiments, the second stripline is embedded between the first stripline and the third stripline.

[0082] In embodiments, the first stripline is sandwiched between the second stripline and the third stripline. For example, the three striplines may be implemented by three material layers, with one of the three material layers sandwiched between two other three material layers.

[0083] In embodiments, the first metallization and / or the second metallization each comprise at least two metallization layers, wherein at least one metallization layer of the at least two metallization layers comprises a superconducting material.

[0084] In embodiments, a first metallization layer of the at least two metallization layers comprises a first superconducting material, wherein a second metallization layer of the at least two metallization layers comprises a second superconducting material

[0085] In embodiments, a first metallization layer of the at least two metallization layers comprises a superconducting material, wherein a second metallization layer of the at least two metallization layers comprises a non-superconducting material.

[0086] In embodiments, the flexible substrate comprises polyimide.

[0087] In embodiments, a first distance between the center conductor and the first metallization is smaller or larger than a second distance between the center conductor and the second metallization.

[0088] In embodiments, the first metallization and the second metallization are connected to one another via a plurality of vias [e.g. electrically].

[0089] In embodiments, the plurality of vias each comprise two via layers [e.g., extending perpendicularly with respect to the first and / or second metallization], wherein a first via layer of the two via layers comprises a superconducting material, and wherein a second via layer of the via layers comprises a non-superconducting material.

[0090] In embodiments, the center conductor is a first center conductor, wherein the flexible waveguide has a second center conductor arranged spaced from the first center conductor [e.g., parallel or vertically offset from the first center conductor].

[0091] In embodiments, the second center conductor is embedded in the flexible substrate. In embodiments, the second center conductor can be structured / constructed identically to the first center conductor. In particular, the second center conductor can comprise at least two striplines, wherein at least one of the at least two striplines comprises a superconducting material. For example, a first stripline can comprise a first superconducting material, while a second stripline has a second superconducting material, wherein the first superconducting material and the second superconducting material are different. Of course, a first stripline of the at least two striplines can also comprise a superconducting material, wherein a second stripline of the at least two striplines can comprise a non-superconducting material.

[0092] In embodiments, the first center conductor and the second center conductor are arranged next to each other in the substrate with respect to the first and / or second metallization [e.g., with respect to a straight line running parallel to the first and / or second metallization] [e.g., such that the first center conductor and the second center conductor intersect a straight line [e.g., at different points] running parallel to the first and / or second metallization].

[0093] For example, the first center conductor and the second center conductor may have the same distance to the first and / or second metallization [e.g., and different distances to the plurality of vias.

[0094] In embodiments, the first center conductor and the second center conductor are arranged one above the other in the substrate with respect to the first and / or second metallization [e.g., with respect to a straight line perpendicular to the first and / or second metallization] [e.g., such that the first center conductor and the second center conductor intersect a straight line [e.g., at different points] perpendicular to the first and / or second metallization].

[0095] For example, the first center conductor and the second center conductor may have different distances to the first and / or second metallization [e.g., and have the same distances to the plurality of vias].

[0096] In embodiments, the first center conductor and the second center conductor are connected to each other (e.g., electrically) via at least one via. In embodiments, the substrate is a first substrate, wherein the flexible waveguide comprises a second substrate and a third metallization (e.g., third shield metallization), wherein the second substrate is arranged between the second metallization and the third metallization, wherein the second center conductor is embedded in the second substrate.

[0097] Further embodiments provide a quantum computer having the following features: a quantum processor, a signal generator and / or signal evaluator, and at least one flexible waveguide according to one of the embodiments described herein for signal transmission between the quantum processor and the signal generator and / or signal evaluator.

[0098] In embodiments, the quantum processor is configured to operate at a cryogenic temperature [e.g., a temperature of less than 1 K].

[0099] In embodiments, the signal generator and / or signal evaluator is configured to operate at a cryogenic temperature [e.g., a temperature of less than 1 K] or a non-cryogenic temperature [e.g., a temperature of more than 253 K].

[0100] In embodiments, the flexible waveguide may have a connection surface, wherein the connection surface is arranged in a plane of the first metallization and is isolated from the first metallization [e.g., electrically], wherein the connection surface is connected to the center conductor [e.g., electrically] [e.g., via one or more vias],

[0101] In embodiments, the flexible waveguide may include a plurality of vias arranged such that the plurality of vias surround the center conductor and the pad.

[0102] In embodiments, the flexible waveguide may have a first pad and a second pad, wherein the first pad and the second pad are arranged in a plane of the first metallization and are insulated from the first metallization [e.g., electrically], wherein the first pad is connected to the first center conductor and the second pad is connected to the second center conductor [e.g., electrically].

[0103] In embodiments, the flexible waveguide may include a plurality of vias, wherein the plurality of vias are arranged such that the plurality of vias surround the first center conductor and the first pad, surround the second center conductor and the second pad, and shield the first center conductor and the first pad from the second center conductor and the second pad.

[0104] In embodiments, the first terminal surface and the second terminal surface may be arranged adjacent to an end of the flexible waveguide, wherein the first terminal surface and the second terminal surface have different distances from the end of the waveguide.

[0105] Further embodiments provide a satellite having the following features: at least one external antenna, a transmitting and / or receiving device, and at least one waveguide according to one of the embodiments described herein for signal transmission between the at least one external antenna and the transmitting and / or receiving device.

[0106] Further embodiments provide a motor vehicle having the following features: a control unit, a sensor, and at least one waveguide according to one of the embodiments described herein for signal transmission between the control unit and the sensor.

[0107] Further embodiments provide a method for manufacturing a flexible waveguide. The method comprises a step of providing a first layer of a flexible substrate. The method further comprises a step of providing a center conductor on the first layer of the flexible substrate, wherein the center conductor comprises at least two striplines, and wherein at least one stripline of the at least two striplines comprises a superconducting material. The method further comprises a step of providing a second layer of the flexible substrate on the first layer of the flexible substrate and the center conductor, such that the center conductor is embedded between the first layer of the flexible substrate and the second layer of the flexible substrate.The method further comprises a step of providing a first metallization and a second metallization, wherein the first metallization is provided on a first side of a stack comprising the first layer of the flexible substrate and the second layer of the flexible substrate, and wherein the second metallization is provided on a second side of the stack opposite the first side. In embodiments, providing the center conductor comprises providing an adhesion layer and / or a diffusion barrier between the first stripline and the second stripline.

[0108] In embodiments, the method further comprises a step of providing a plurality of vias between the first metallization and the second metallization [e.g., wherein the vias electrically connect the first metallization and the second metallization to each other].

[0109] Further embodiments provide a method for producing a flexible waveguide. The method comprises a step of providing a first layer of a flexible substrate of the flexible waveguide. The method further comprises a step of forming at least one hole through the first layer of the flexible substrate. The method further comprises a step of coating both sides [e.g. by sputtering, thermal vapor deposition, or electroplating] of the first layer of the flexible substrate with a first metallization, wherein during the double-sided coating, side walls of the at least one hole are coated with the first metallization in order to obtain at least one via. The method further comprises a step of structuring [e.g. by a combination of photolithography and etching [e.g.wet chemical and / or plasma-assisted] of the first metallization in order to obtain a center conductor of the flexible waveguide on a first side of the first layer of the flexible substrate and to obtain a connection surface for electrically contacting the center conductor on a second side of the first layer of the flexible substrate facing away from the first side, wherein the connection surface and the center conductor are [electrically] connected to one another via the at least one via. Furthermore, the method comprises a step of providing a second layer of the flexible substrate on the first side of the first layer of the flexible substrate. Furthermore, the method comprises a step of forming a plurality of holes through the first layer and the second layer of the flexible substrate.The method further comprises a step of coating the flexible substrate on both sides with a second metallization, wherein, during the double-sided coating, sidewalls of the plurality of holes are coated with the second metallization to obtain a plurality of vias. The method further comprises a step of structuring the second metallization to obtain a first shielding metallization of the flexible waveguide.

[0110] In embodiments, the first metallization may comprise at least two first metallization layers, wherein a first layer of the at least two first metallization layers comprises a superconducting material, and wherein a second layer of the at least two first metallization layers comprises a non-superconducting material.

[0111] In embodiments, the second metallization may comprise at least two second metallization layers, wherein a third layer of the at least two second metallization layers comprises a superconducting material, and wherein a fourth layer of the at least two second metallization layers comprises a non-superconducting material.

[0112] In embodiments, the plurality of vias may be arranged such that the plurality of vias surround the center conductor and the pad.

[0113] In embodiments, the center conductor may be a first center conductor, wherein the pad is a first pad, wherein a second center conductor and a second pad are formed during patterning of the first metallization, wherein the second center conductor and the second pad are connected to each other via a via, wherein the plurality of vias are arranged such that the plurality of vias surround the first center conductor and the first pad, surround the second center conductor and the second pad, and shield the first center conductor and the first pad from the second center conductor and the second pad.

[0114] In embodiments, the first connection surface and the second connection surface may have different distances from one end of the waveguide in the wave propagation direction of the flexible waveguide.

[0115] Embodiments of the present invention are described in more detail with reference to the accompanying figures. They show:

[0116] Fig. 1a is a schematic sectional view through a flexible waveguide transverse to the wave propagation direction, according to an embodiment,

[0117] Fig. 1b is a schematic sectional view through a flexible waveguide along the wave propagation direction, according to an embodiment,

[0118] Fig. 2 is a schematic sectional view through a flexible waveguide transverse to the wave propagation direction, according to an embodiment, Fig. 3a is a schematic sectional view through a flexible waveguide transverse to the wave propagation direction, wherein the waveguide has a center conductor with two striplines as superconductors and normal conductors, according to an embodiment,

[0119] Fig. 3b is a schematic sectional view through a flexible waveguide transverse to the wave propagation direction, wherein the waveguide has a center conductor with three striplines as superconductors and normal conductors, according to an embodiment,

[0120] Fig. 4a shows a diagram of the simulated insertion loss in dB of a flexible waveguide with superconductor and normal conductor plotted against the frequency in GHz,

[0121] Fig. 4b shows a diagram of the simulated insertion loss in dB of a niobium waveguide plotted against the frequency in GHz,

[0122] Fig. 5 is a schematic sectional view through a flexible waveguide transverse to the wave propagation direction, wherein the flexible waveguide has two center conductors embedded in different substrates, according to an embodiment,

[0123] Fig. 6a is a schematic sectional view through a flexible waveguide transverse to the wave propagation direction, wherein the flexible waveguide has two center conductors arranged side by side, according to an embodiment,

[0124] Fig. 6b is a schematic sectional view through a flexible waveguide transverse to the wave propagation direction, wherein the flexible waveguide has two center conductors arranged one above the other, according to an embodiment,

[0125] Fig. 7 is a schematic sectional view through a flexible waveguide transverse to the wave propagation direction, wherein the flexible waveguide has two center conductors arranged one above the other, which are connected to each other via vias, according to an embodiment, Fig. 8 is a schematic sectional view transverse to the wave propagation direction of a center conductor with three striplines, wherein a first stripline is embedded between a second stripline and a third stripline, according to an embodiment,

[0126] Fig. 9 is a flow chart of a method for producing a flexible

[0127] Waveguide, according to one embodiment,

[0128] Fig. 10a-g show schematic sectional views of the flexible waveguide after different steps of a manufacturing method for producing the flexible waveguide, according to an embodiment,

[0129] Fig. 11 is a schematic view of connection surfaces of the flexible waveguide, according to an embodiment,

[0130] Fig. 12 is a schematic block diagram of a quantum computer according to an embodiment,

[0131] Fig. 13 is a schematic block diagram of a satellite with a flexible waveguide, according to an embodiment,

[0132] Fig. 14 is a schematic sectional view of a flexible waveguide along the wave propagation direction, wherein at least one high-frequency component is integrated into the flexible waveguide, according to an embodiment,

[0133] Fig. 15 is a schematic sectional view of the flexible waveguide along the wave propagation direction, wherein several RF components are integrated into the flexible waveguide, which are arranged offset from one another according to a regular pattern, according to an embodiment,

[0134] Fig. 16 is a schematic sectional view of the flexible waveguide along the wave propagation direction, wherein several RF components are integrated into the flexible waveguide 100, which are arranged diagonally offset from one another, according to an embodiment,

[0135] Fig. 17 is a schematic sectional view of the flexible waveguide along the wave propagation direction, wherein several RF components are integrated into the flexible waveguide, which are arranged offset from one another according to a non-regular pattern, according to an embodiment,

[0136] Fig. 18 is a schematic sectional view of the flexible waveguide along the wave propagation direction, wherein several RF components are integrated into the flexible waveguide, which are arranged in series with each other and / or extend over the entire length of the flexible waveguide, according to an embodiment,

[0137] Fig. 19a is a schematic sectional view through the flexible waveguide along a plane parallel to the first and second metallization, wherein the high-frequency component is a filter implemented by stub lines, according to an embodiment,

[0138] Fig. 19b is a schematic sectional view through the flexible waveguide along a plane parallel to the first and second metallization, wherein the high-frequency component is a filter implemented by stubs, according to an embodiment,

[0139] Fig. 19c is a schematic sectional view through the flexible waveguide along a plane parallel to the first and second metallization, wherein the high-frequency component is a filter implemented by open meandering stubs, according to an embodiment,

[0140] Fig. 19d is a schematic sectional view through the flexible waveguide along a plane parallel to the first and second metallization, wherein the high-frequency component is a filter implemented by a terminated meander-shaped stub, according to an embodiment,

[0141] Fig. 20a is a schematic sectional view through a flexible waveguide along a plane that runs parallel to the first and second metallization, wherein the high-frequency component is an attenuator implemented by striplines, according to an embodiment, Fig. 20b is a schematic sectional view through the flexible waveguide of Fig. 20a transverse to the wave propagation direction, according to an embodiment,

[0142] Fig. 21a is a schematic sectional view through the flexible waveguide along a plane parallel to the first and second metallization, wherein the high-frequency component is a directional coupler implemented by striplines, according to an embodiment,

[0143] Fig. 21b is a schematic sectional view through the flexible waveguide transverse to the wave propagation direction, according to an embodiment, according to an embodiment,

[0144] Fig. 22a is a schematic sectional view through the flexible waveguide along a plane parallel to the first and second metallization, wherein the high-frequency component is a directional coupler implemented by sawtooth-shaped striplines, according to an embodiment,

[0145] Fig. 22b is a schematic sectional view through the flexible waveguide of Fig. 22a transverse to the wave propagation direction, according to an embodiment,

[0146] Fig. 23 is a schematic sectional view through the flexible waveguide along a plane parallel to the first and second metallization, wherein the high-frequency component is a transformer implemented by striplines, according to an embodiment,

[0147] Fig. 24a is a schematic sectional view through the flexible waveguide along a plane parallel to the first and second metallization, wherein the high-frequency component is a power divider implemented by at least one stripline, according to a first embodiment,

[0148] Fig. 24b is a schematic sectional view through the flexible waveguide along a plane that runs parallel to the first and second metallization, wherein the high-frequency component is a power divider implemented by at least one stripline, according to a second embodiment, Fig. 24c is a schematic sectional view through the flexible waveguide along a plane that runs parallel to the first and second metallization, wherein the high-frequency component is a power divider implemented by at least one stripline, according to a third embodiment.

[0149] In the following description of the embodiments of the present invention, identical or equivalent elements in the figures are provided with the same reference numerals so that their description is interchangeable.

[0150] Before describing embodiments of the integration of high-frequency components into a flexible waveguide in Section 2, the underlying flexible waveguide is first described in Section 1.

[0151] 1. Flexible waveguide

[0152] The (highly integrated) flexible waveguide described below enables the transmission of a wide range of high-frequency signals in a small space and with a small cross-section. This can both solve the space problem and reduce (or even minimize) the passive heat input through the cables.

[0153] Fig. 1a shows a schematic sectional view through a flexible waveguide 100 transverse (perpendicular) to the wave propagation direction, while Fig. 1b shows a schematic sectional view through the flexible waveguide longitudinal to the wave propagation direction, according to one embodiment. The waveguide 100 comprises a first metallization 102 (e.g., first shielding metallization), a second metallization 104 (e.g., second shielding metallization), a flexible substrate 106 arranged between the first metallization 102 and the second metallization 104, and a center conductor 108 (or inner conductor) embedded in the flexible substrate 106. The center conductor 108 comprises at least two striplines 110_1, 110_2, wherein at least one of the at least two striplines comprises a superconducting material.

[0154] In embodiments, a first stripline 110_1 of the at least two striplines 110_1, 110_2 can comprise a first superconducting material, wherein a second stripline 110_2 of the at least two striplines 110_1, 110_2 can comprise a second superconducting material, wherein the first superconducting material and the second superconducting material are different. The first superconducting material and the second superconducting material can be two different superconducting materials from the superconducting materials listed in Table 1, such as niobium and aluminum, niobium and lead, or niobium and aluminum. It should be noted here that the two different superconducting materials are not limited to a specific material combination; rather, the superconducting materials listed in Table 1 can be combined with one another in any desired way.In other words, any of the superconducting materials listed in Table 1 can be combined with any other superconducting material listed in Table 1.

[0155] In embodiments, a first stripline 110_1 of the at least two striplines 110_1, 110_2 may comprise a superconducting material, wherein a second stripline 110_2 of the at least two striplines 110_1, 110_2 may comprise a non-superconducting material.

[0156] The superconducting material can be any superconducting material listed in Table 1, while the non-superconducting material can be any non-superconducting material listed in Table 2. For example, the superconducting material can be one of niobium, aluminum, lead, indium, zinc, tantalum, and niobium nitride, while the non-superconducting material can be one of copper, gold, and silver. It should be noted that the superconducting material and the non-superconducting material are not limited to any specific material combination; rather, the superconducting materials listed in Table 1 and the non-superconducting materials listed in Table 2 can be arbitrarily combined. In other words, any of the superconducting materials listed in Table 1 can be combined with any non-superconducting material listed in Table 2.

[0157] In addition to the superconducting materials, the following Table 1 also shows the transition temperatures, i.e. the temperatures above which the respective materials are superconducting.

[0158] Table 1: Superconducting materials and transition temperature [4]

[0159] Non-superconducting materials are listed in Table 2 below. Table 2: Non-superconducting materials

[0160] In embodiments, the other metallizations (e.g. first metallization, second metallization and / or a plurality of vias (cf. Figs. 3a and 3b) may each have two layers, wherein at least one of the two layers comprises superconducting material.

[0161] In embodiments, the substrate may comprise a polymer, such as polyimide.

[0162] In some embodiments, suitable waveguides for high-frequency signals can be produced based on (polyimide) films or (polyimide) substrates coated with various metals (e.g., copper, niobium, aluminum, etc.). If the substrate is coated with superconducting materials (e.g., niobium or aluminum), superconducting cables can also be constructed. In some embodiments, a waveguide, such as a stripline, is realized with at least three metal layers.

[0163] In embodiments, the substrate is implemented using a flexible material such as polyimide or thin polyimide films, whereby the entire waveguide is flexible within certain limits and can be used and bent in a similar way to a cable.

[0164] By appropriately placing vias at regular intervals, sufficiently high shielding attenuation can be achieved, so that even with adjacent waveguides, the decoupling is less than or equal to -60 dB. These so-called via fences can be arranged singly, doubled, or n-fold in series to achieve even lower crosstalk, where n is a natural number greater than or equal to one. In the case of multi-row via fences, these can also be offset from each other to achieve even higher signal integrity; for example, by half a via grid.

[0165] With suitable dimensioning and sufficient manufacturing tolerances and manufacturing capabilities, a very highly integrated and flexible cable with multiple waveguides can be realized, such as 100 waveguides per inch.

[0166] Fig. 2 shows a schematic sectional view through a flexible waveguide transverse to the wave propagation direction, according to one embodiment. In other words, Fig. 2 shows a cross-section of a flexible waveguide (e.g., a flexible cable) with several indicated lines and three metal layers. As already described with reference to Figs. 1a and 1b, the waveguide 100 comprises a first metallization 102, a second metallization 104, a flexible substrate 106 arranged between the first metallization 102 and the second metallization 104, and a center conductor 108 embedded in the flexible substrate 106.

[0167] In embodiments, the center conductor 108 may be arranged asymmetrically with respect to the first metallization 102 and the second metallization 104. Thus, a first distance between the center conductor 108 and the first metallization 102 may be smaller than a second distance between the center conductor 108 and the second metallization 104.

[0168] As further indicated in Fig. 2, in embodiments, the flexible substrate 106 may comprise a first film 112_1 and a second film 112_2, with the center conductor 108 disposed between the first film 112_1 and the second film 112_2. The first film 112_1 and the second film 112_2 may be polyimide films, for example.

[0169] As can also be seen in Fig. 2, in embodiments, the waveguide 100 can have a plurality of vias 114. The plurality of vias 114 can be arranged between the first metallization 102 and the second metallization 104, or the first metallization 102 and the second metallization 104 can be connected to one another (e.g., electrically) via the plurality of vias 114.

[0170] In embodiments, the plurality of vias 114 may be arranged to shield the center conductor 108. For example, the plurality of vias may be arranged on both sides (ie, on opposite sides of the center conductor 108) along the center conductor 108, e.g., in the form of two via fences.

[0171] In embodiments, the flexible waveguide 100 may also comprise further center guides, which may be arranged in the same substrate 106 between the first and second metallizations 102, 104, for example, to the right and / or left with respect to the plurality of vias 114 shown in Fig. 2, or in other words, such that the center guides are separated from one another by so-called via fences running between the first and second metallizations 102, 104. In this case, the plurality of vias may serve to reduce crosstalk between the different center guides. Of course, the flexible waveguide 100 may also comprise further center guides arranged in other substrates, e.g., with respect to Fig. 2, above the second metallization 104 and / or below the first metallization 102.

[0172] In other words, Fig. 2 shows a cross-section of an exemplary flexible waveguide (e.g., flexible cable). In the flexible waveguide (e.g., flexible cable) shown, the center conductor 108 can, in particular, be arranged such that the center conductor 108 is arranged closer to the lower shielding metallization 102 than to the upper shielding metallization 104 (so-called "asymmetric structure"). In the asymmetric structure, the layer thicknesses of the dielectrics 112_1 and 112_2 are consequently selected to be different. This, on the one hand, achieves the technical advantage that a layer change or connector transition can be carried out more easily. The structure of the flexible waveguide could, for example, have the following layer thicknesses: film 2 with 50 pm, film 1 with 25 pm, and a metallization thickness of 0.5 pm.The asymmetrical design provides the technical advantage that the adaptation of the characteristic impedance at the transition to a connector can be improved.

[0173] Fig. 3a shows a schematic sectional view through a flexible waveguide 100 transverse to the wave propagation direction, wherein the waveguide 100 has a center conductor 108 with two striplines 110_1, 110_2 as superconductors and normal conductors, according to an exemplary embodiment. In other words, Fig. 3a shows a cross-section of a flexible waveguide (e.g., a flexible cable) with superconductor and normal conductor materials.

[0174] As already described with reference to Figs. 1a and 1b, the center conductor 108 may comprise two striplines 110_1, 110_2. A first stripline 110_1 of the at least two striplines 110_1, 110_2 may comprise a superconducting material, while a second stripline 110_2 of the at least two striplines 110_1, 110_2 may comprise a non-superconducting material.

[0175] As shown by way of example in Fig. 3a, the first stripline 110_1 and the second stripline 110_2 can be arranged one above the other with respect to the first and / or second metallization 102, 104, for example such that the first stripline and the second stripline 110_2 intersect a straight line 152 at different points that is perpendicular to the first and / or second metallization 102, 104. Alternatively, the first stripline 110_1 and the second stripline 110_2 can also be arranged side by side with respect to the first and / or second metallization 102, 104, for example such that the first stripline and the second stripline 110_2 intersect a straight line 154 at different points that runs parallel to the first and / or second metallization 102, 104.

[0176] Fig. 3b shows a schematic sectional view through a flexible waveguide 100 transverse to the wave propagation direction, wherein the waveguide 100 has a center conductor 108 with three striplines 110_1, 110_2, 110_3 as superconductors and normal conductors, according to one embodiment. In other words, Fig. 3b shows a cross-section of a flexible waveguide (e.g., a flexible cable) with superconductor and normal conductor materials—a three-part center conductor.

[0177] Compared to the embodiment shown in Fig. 3a, the center conductor 108 shown in Fig. 3b comprises three striplines 110_1-110_3. A first stripline 110_1 and a third stripline 110_3 can each comprise a superconducting material (e.g., the same superconducting material or different superconducting materials), while a second stripline 110_2 can comprise a non-superconducting material. Of course, in embodiments, the first stripline 110_1 and the third stripline 110_3 can each comprise non-superconducting materials, while the second stripline 110_2 comprises a superconducting material.

[0178] As indicated in Figs. 3a and 3b, in embodiments, the other metallizations, ie first metallization 102, second metallization 104 and / or the plurality of vias 114, may also have multiple layers, wherein a first layer comprises a superconducting material and a second layer comprises a non-superconducting material.

[0179] For example, the first metallization 102 may include a first layer 102_1 of superconducting material and a second layer 102_2 of non-superconducting material. The second metallization 104 may include a first layer 104_1 of non-superconducting material and a second layer 104_2 of superconducting material. The vias may include a first layer 114_1 of superconducting material and a second layer 114_2 of non-superconducting material.

[0180] In other words, Figs. 3a and 3b show the cross-section of further exemplary flexible waveguides (e.g., flexible cables). The flexible waveguides (e.g., flexible cables) shown are characterized by the fact that the metallization of the center conductor and / or the shielding was implemented using a material combination of at least one superconducting material (e.g., niobium below the critical temperature) and one non-superconducting material (e.g., copper). Optionally, an adhesion layer (e.g., titanium-tungsten) can be used as part of the material combination to bond the superconducting material and the non-superconducting material together. The adhesion layer can be incorporated into the material combination during manufacturing.

[0181] If the substrate is coated only with copper, for example, superconductivity cannot be achieved, but the waveguide (e.g., the cable) can also be used at higher temperatures (e.g., above the transition temperature of superconducting materials). The high shielding attenuation and decoupling described above are retained in this case as well. If, on the other hand, the substrate is coated with aluminum, it can function both as a superconductor at cryogenic temperatures and as a normal conductor at higher temperatures.

[0182] By combining several conductor materials consisting of normal conductor and superconductor (e.g., copper and niobium, copper and aluminum), a particularly low-attenuation waveguide can be easily realized from the cryogenic temperature range through the room temperature range to the high temperature range (e.g., temperatures in the three-digit degrees Celsius). In Figs. 3a and 3b, the normal conductor is designated by reference numerals 110_2, 102_2, 104_1, and 114_2, and the superconductors by reference numerals 110_1, 110_3, 102_1, 104_2, and 114_1. This combination is also possible in reverse. Furthermore, a three-part inner conductor in the combination of normal conductor-superconductor-normal conductor or superconductor-normal conductor-superconductor is also possible (see Fig. 3b). The magnitude of the simulated S21 parameters (insertion loss) in decibels for one millimeter of cable length can be seen in Fig. 4a.

[0183] In detail, Fig. 4a shows a graph showing the simulated insertion loss in dB of a flexible waveguide with a superconductor and a normal conductor plotted against frequency in GHz. A first curve 50 describes the insertion loss of the superconductor and the normal conductor at room temperature, while a second curve 52 shows the insertion loss of the superconductor and the normal conductor at cryogenic temperatures. In other words, Fig. 4a shows a graph showing simulated S21 parameters of the superconductor and the normal conductor at room temperature (50) and cryogenic temperatures (52).

[0184] This shows that the waveguide (e.g. the cable) can be used at both cryogenic and higher temperatures. For comparison, a flexible waveguide (e.g. flexible cable) based purely on niobium is shown in Fig. 4b. In detail, Fig. 4b shows a diagram of the simulated insertion loss in dB of a niobium waveguide plotted against the frequency in GHz. A first curve 60 describes the insertion loss of the niobium waveguide at room temperature, while a second curve 62 shows the insertion loss of the niobium waveguide at cryogenic temperatures. In other words, Fig. 4b shows a diagram of simulated S21 parameters of a niobium waveguide (e.g. niobium cable) at room temperature (60) and cryogenic temperatures (62).

[0185] Fig. 5 shows a schematic sectional view through a flexible waveguide 100 transverse to the wave propagation direction, wherein the flexible waveguide 100 has two center conductors 108 embedded in different substrates, according to one embodiment. In other words, Fig. 5 shows an example of an n*3 layer flexible waveguide (e.g., flexible cable) with correspondingly more channels. The first center conductor 108_1 is embedded in a first substrate 106, which is arranged between the first metallization 102 and the second metallization 104, while the second center conductor 108_2 is embedded in a second substrate 106_2, which is arranged between the second metallization 104 and a third metallization 116.

[0186] As indicated in Fig. 5, in embodiments, the plurality of vias may connect the first metallization 102, the second metallization 104 and the third metallization 116 (e.g., electrically).

[0187] In other words, Fig. 5 shows the cross-section of another exemplary flexible waveguide (e.g., flexible cable). The waveguide (e.g., cable) shown uses more than three metal layers. The structure could, for example, correspond to the sequence of shielding - center conductor - shielding - center conductor - shielding - (...). Such an arrangement allows multiple layers to be realized, thereby further increasing the integration density of the flexible waveguide (e.g., flexible cable).

[0188] Fig. 6a shows a schematic sectional view through a flexible waveguide 100 transverse to the wave propagation direction, wherein the flexible waveguide 100 has two center conductors 108 arranged next to one another, according to an embodiment.

[0189] Fig. 6b shows a schematic sectional view through a flexible waveguide 100 transverse to the wave propagation direction, wherein the flexible waveguide 100 has two center conductors 108 arranged one above the other, according to one embodiment. As already described above for the other embodiments, the waveguide 100 shown in Figs. 6a and 6b comprises a first metallization 102, a second metallization 104, a flexible substrate 106 arranged between the first metallization 102 and the second metallization 104, and a plurality of vias 114 that run between the first metallization 102 and the second metallization 104 and connect them (e.g., electrically).

[0190] Compared with the embodiments described above, the flexible waveguide 100 shown in Figs. 6a and 6b comprises not only one center conductor, but two center conductors 108_1 and 108_2.

[0191] In the embodiment shown in Fig. 6a, the two center conductors 108_1 and 108_2 are arranged next to one another, e.g. such that the first center conductor 108_1 and the second center conductor 108_2 intersect a straight line 156 at different points, which runs parallel to the first and / or second metallization 102, 104.

[0192] In the embodiment shown in Fig. 6b, the two center conductors 108_1 and 108_2 are arranged one above the other, so that the first center conductor 108_1 and the second center conductor 108_2 intersect a straight line 158 at different points, which is perpendicular to the first and / or second metallization 102, 104.

[0193] In other words, Figs. 6a and 6b show cross-sections of other exemplary flexible waveguides (e.g., flexible cables). The flexible waveguides (e.g., flexible cables) shown use different arrangements with center conductors (directly) stacked or (directly) adjacent to each other for carrying (e.g., differential) signals. For example, this can achieve higher common-mode rejection and thus better signal integrity.

[0194] The center conductors shown in Fig. 5a-6b can of course each have at least two striplines, wherein at least one of the at least two striplines has superconducting material.

[0195] In embodiments, the other metallizations (e.g., first metallization, second metallization, and / or the plurality of vias) may each comprise two layers, wherein at least one of the two layers comprises superconducting material. Fig. 7 shows a schematic sectional view through a flexible waveguide 100 transverse to the wave propagation direction, wherein the flexible waveguide 100 has two center conductors 108 arranged one above the other, which are connected to one another via vias 118, according to one embodiment. In other words, Fig. 7 shows a cross-section of a flexible waveguide (e.g., a flexible cable) with two center conductors, wherein the two center conductors are connected to one another by means of a via.

[0196] As already described above, the waveguide 100 shown in Fig. 7 comprises a first metallization 102, a second metallization 104, a flexible substrate 106 arranged between the first metallization 102 and the second metallization 104, and a plurality of vias 114 extending between the first metallization 102 and the second metallization 104 and connecting them (e.g., electrically). Furthermore, the waveguide 100 comprises two center conductors 108_1 and 108_2 embedded in the substrate 106 and arranged one above the other, which are connected to each other via vias 118.

[0197] In other words, Fig. 7 shows a cross-section of another exemplary flexible waveguide (e.g., flexible cable). In the flexible waveguide (e.g., flexible cable) shown, two center conductors are connected by means of a through-hole (i.e., a via) to form a conductor with a larger cross-section. This allows for higher current-carrying capacity and better heat dissipation.

[0198] Fig. 8 shows a schematic sectional view transverse to the wave propagation direction of a center conductor 108 with three striplines 110_1-110_3, wherein a first stripline 110_1 is embedded between a second stripline 110_2 and a third stripline 110_3, according to one embodiment. As can be seen in Fig. 8, the first stripline 110_1 can be arranged on the second stripline 110_2, wherein the third stripline 110_3 can be arranged on the first stripline 110_1 and the second stripline 110_2, such that the third stripline 110_3 and the second stripline 110_3 embed the first stripline 110_1.

[0199] The center conductor 108 is arranged in Fig. 8 on a first film 112_1 of a flexible substrate. A second film could be arranged on the center conductor 108 and the first film 112_2 in order to embed the center conductor 108 in the first film 112_1 and the second film. The two films could then again form a flexible substrate, wherein the substrate can be arranged between two metallizations in order to form a flexible waveguide, as already described in detail above. All features of the exemplary embodiments disclosed herein and described or shown can be combined with one another as desired in order to simultaneously realize their technical advantages. For example, the asymmetric structure can be combined with the material combination of superconducting material and non-superconducting material. Furthermore, a ground-referenced signal (GRP) can in principle be used.A single-ended signal or a differential signal can be transmitted via the flexible waveguide (e.g. flexible cable).

[0200] In addition, multiple layers can be arranged one above the other, with each layer having an identical structure. Alternatively, the individual layers can also have different structures, depending on the application.

[0201] 1.2. Manufacturing process for a flexible waveguide

[0202] An embodiment of a method for producing a flexible waveguide is described below.

[0203] Fig. 9 shows a flowchart of a method 200 for manufacturing a flexible waveguide, according to an embodiment. The method 200 comprises a step 202 of providing a first layer of a flexible substrate. The method 200 further comprises a step 204 of providing a center conductor on the first layer of the flexible substrate, wherein the center conductor comprises at least two striplines, and wherein at least one stripline of the at least two striplines comprises a superconducting material. The method 200 further comprises a step 206 of providing a second layer of the flexible substrate on the first layer of the flexible substrate and the center conductor, such that the center conductor is embedded between the first layer of the flexible substrate and the second layer of the flexible substrate.Furthermore, the method 200 comprises a step 208 of providing a first metallization and a second metallization, wherein the first metallization is provided on a first side of a stack of the first layer of the flexible substrate and the second layer of the flexible substrate, and wherein the second metallization is provided on a second side of the stack opposite the first side.

[0204] A further embodiment of a method for manufacturing a flexible waveguide is described below. Such a method enables, for example, the automated and reproducible production of flexible waveguides (e.g., flexible cables). The production and automated manufacture of flexible three-layer waveguides can, for example, be carried out consecutively in several process steps, for example, in an automated roll-to-roll process, as shown in Figs. 10a-g.

[0205] In detail, Figs. 10a-g show schematic cross-sectional views of the flexible waveguide after different steps during its manufacturing. In other words, Figs. 10a-g show process steps for producing flexible waveguides.

[0206] In detail, Fig. 10a shows a schematic sectional view of the flexible waveguide during its manufacture after a step of providing a first layer of a flexible substrate of the flexible waveguide and a step of forming at least one hole 120 through the first layer of the flexible substrate.

[0207] In exemplary embodiments, vias and alignment marks can first be laser-drilled through the entire thickness of a flexible substrate film, for example, made of polyimide (PI) (e.g., with a thickness of 25 μm). The vias can later serve as signal vias for electrical contact between the front and back of the substrate film. The alignment marks serve to align the metallization with the vias during lithographic patterning.

[0208] Fig. 10b shows a schematic sectional view of the flexible waveguide during its manufacture after a step of coating (e.g., by sputtering, thermal vapor deposition, or electroplating) the first layer 112_1 of the flexible substrate with a first metallization 102, wherein, during the double-sided coating, side walls of the at least one hole 120 are coated with the first metallization to obtain at least one via.

[0209] In embodiments, in the step of Fig. 10b, a metal layer can be deposited on both sides and in the borehole walls of the foil from the step of Fig. 10a, e.g., by sputtering. The surface of the substrate foil may need to be activated beforehand (within the sputtering tool, without interrupting the vacuum). This can ensure that the metal adheres to the foil as required. Another possibility for improving the adhesion between a metal layer, such as niobium, and a PI foil can be achieved by depositing TiW, for example, as an intermediate layer. To produce superconducting structures, metallizations (e.g., niobium) can be applied that become superconducting below a critical temperature.

[0210] During this process step, it is also possible to deposit different metals, allowing different functions to be integrated into a very small space depending on requirements. For example, signal lines could be made partly of niobium and partly of copper to optimize heat conduction within the cable.

[0211] Fig. 10c shows a schematic sectional view of the flexible waveguide during its manufacture after a step of structuring (e.g. by a combination of photolithography and etching (e.g. wet chemical and / or plasma-assisted) of the first metallization 102 in order to obtain a center conductor of the flexible waveguide on a first side of the first layer of the flexible substrate and to obtain a connection surface for electrically contacting the center conductor on a second side of the first layer of the flexible substrate facing away from the first side, wherein the connection surface and the center conductor are connected to one another via the at least one via (e.g. electrically).

[0212] In exemplary embodiments, the pre-processed film can be laminated on both sides with a photoresist. The structure of the signal lines and the contact pads of the flexible waveguide to be manufactured are defined on the front and back, for example, by (double-sided) UV exposure. The exposed area of ​​the photoresist crosslinks (negative tone resist) and becomes insoluble. The unexposed part is dissolved in a solution, e.g., sodium carbonate (Na2CO3), and washed off. The structuring of the metallization on the front and back of the film is achieved by etching. This can be done either by plasma or wet etching. The photoresist is then stripped off in a solution, e.g., potassium hydroxide (KOH).

[0213] Fig. 10d shows a schematic sectional view of the flexible waveguide during its manufacture after a step of providing a second layer 112_2 of the flexible substrate on the first side of the first layer of the flexible substrate.

[0214] In embodiments, the metallized foil can then be laminated to a second dielectric layer, with or without an (acrylic) adhesive between the two foil layers. Fig. 10e shows a schematic cross-sectional view of the flexible waveguide during its manufacture after a step of forming a plurality of holes through the first layer 112_1 and the second layer 112_2 of the flexible substrate.

[0215] In some embodiments, additional vias and new alignment marks can be laser-drilled through the laminated foil. These vias later serve to establish electrical contact between the front and back sides of the waveguide's outer shield layer. The laser-applied alignment marks are used to position the metallization.

[0216] Fig. 10f shows a schematic sectional view of the flexible waveguide during its manufacture after a step of coating the flexible substrate on both sides with a second metallization 124, wherein during the double-sided coating, side walls of the plurality of holes are coated with the second metallization to obtain a plurality of vias.

[0217] In exemplary embodiments, an additional metal layer is deposited on the pre-processed substrate on the outer surfaces and the previously created bore walls as a shield, for example, using sputtering. This electrically connects the front and back sides of the shielding layer via vias. Niobium and / or copper, for example, can be used as the shielding metallization, so that no heat is generated due to conduction losses in the superconducting state. The additionally applied copper could serve to dissipate passive heat caused by temperature differences in the cryostat.

[0218] Fig. 10g shows a schematic sectional view of the flexible waveguide during its manufacture after a step of structuring the second metallization 124 to obtain a first shielding metallization of the flexible waveguide.

[0219] In embodiments, a photoresist can be applied to the layer composite and exposed to light in order to pattern the shield layer metallization. The structuring of niobium can be achieved, for example, by plasma etching. When using other metallization, such as Cu, wet etching can be performed using, for example, sodium persulfate solution (Na2S2O8). Both etching steps can be performed with the same photoresist layer. Through the structuring in the step shown in Fig. 10g, the contact areas created in the step of Fig. 10c are finally electrically separated from the surrounding shield layers. This results, for example, in a contact area according to Fig. 11.

[0220] 1.3. Connection surfaces of the flexible waveguide

[0221] Fig. 11 shows a schematic view of connection surfaces 130_1-130_3 of the flexible waveguide 100 according to one embodiment. In other words, Fig. 11 shows an exemplary contact surface of a flexible waveguide 100.

[0222] As can be seen in Fig. 11, the connection pads 130_1-130_3 can be exposed in a plane of the first metallization 102 (or alternatively the second metallization), ie, electrically insulated from the first metallization 102. The connection pads 130_1-130_3 can be connected to respective center conductors of the flexible waveguide 100 via respective vias 132_1-132_3.

[0223] In embodiments, the flexible waveguide 100 may include a plurality of vias 134, wherein the plurality of vias 134 are arranged such that the plurality of vias 134 surround the first pad 130_1 (and the first center conductor), surround the second pad 130_2 (and the second center conductor), and surround the third pad 130_3 (and the third center conductor), and shield the first pad 130_1, the second pad 130_2, and the third pad 130_3 from each other. This may reduce crosstalk between the different pads and the respective center conductors.

[0224] In embodiments, the three connection surfaces 130_1-130_3 may have different distances from an end 134 of the flexible waveguide.

[0225] 1.4. Applications of the flexible waveguide

[0226] Flexible waveguide designs are used when signals need to be transmitted in a very small space while simultaneously achieving optimized heat conduction. The latter is made possible, in particular, by a combination of materials and the described layer structure.

[0227] 1.4.1 Quantum Computing with Superconducting Qubits One conceivable application of the flexible waveguide (e.g., interconnection system) is signal transmission in a quantum computer. Examples of flexible waveguides can be used to replace coaxial cables. This can significantly increase the signal density in the cryostat. By using superconducting materials for the signal lines and shielding layers of the flexible waveguide (e.g., niobium), heat losses can be reduced. At the same time, additional metal layers can be added to optimize heat conduction so that only a small amount of passive heat is transferred from one temperature level in the cryostat to the next. This makes it possible to increase the number of lines in the cryostat. Thus, the flexible waveguide can ensure the signal and power supply in the cryostat even as the number of qubits in the quantum computer increases.

[0228] Fig. 12 shows a schematic block diagram of a quantum computer 300 according to one embodiment. In other words, Fig. 12 shows an installation of flexible waveguides in the cryostat. The quantum computer 300 comprises a quantum processor (Quantum Processing Unit, QPU) 302, a signal generator and / or signal evaluator 304, a cryostat for generating different temperature levels (e.g., room temperature, 300 K, 4 K, 1.5 K, 100 mK, 20 mK), and at least one flexible waveguide 100 for signal routing between the quantum processor 304 and the signal generator and / or signal evaluator 304.

[0229] As can be seen in Fig. 12, the at least one flexible waveguide 100 can be used across all temperature levels (e.g. room temperature, 300 K, 4 K, 1.5 K, 100 mK, 20 mK), ie continuously from a temperature level (e.g. room temperature) of the signal generator and / or signal evaluator 304 to a temperature level of the quantum processor, e.g. via feedthroughs in the temperature levels (or temperature levels) of the cryostat.

[0230] Examples of implementation allow lines to be led directly from the 4K stage into the so-called mixing chamber (MXC), since the heat transfer is reduced (or even minimized) by the material combination and thus the desired temperature of a few mK can be achieved despite passive heat conduction.

[0231] The shielding concept also ensures low crosstalk between the lines and thus high signal integrity. Manufacturing can be carried out according to the process described above. 1.4.2 Phase-controlled array antennas

[0232] Embodiments of the flexible waveguide can be used to connect remote phased array antennas, for example, in radar and communications applications. Superconducting materials are typically not used in such cases, as these are not cryogenic applications. Good conductors, such as copper or silver, are more suitable here. This enables a more compact antenna with few or no active components. Active signal processing takes place in a central unit.

[0233] This could be the case, for example, in a satellite. The highly integrated cable connects an antenna array mounted on the outside of the satellite to a central unit that transmits and receives the data and processes it accordingly. This has the advantage that most of the waste heat from the transmitting and receiving system is generated elsewhere. This may simplify cooling. Hybrid solutions are also conceivable here, in which some electronic components such as phase shifters or amplifiers are integrated into the antennas, while the connection to the transmitting and receiving unit is established via many highly integrated waveguides.

[0234] Fig. 13 shows a schematic block diagram of a satellite 320 with a flexible waveguide 100, according to one embodiment. The satellite 320 includes an external antenna 322, such as an antenna array, and a transmitting and / or receiving device 324, wherein the flexible waveguide 100 is used for signal transmission between the at least one external antenna 322 and the transmitting and / or receiving device 324.

[0235] Remote antennas connected by highly integrated cables are also conceivable for radar devices with electronically controlled group antennas.

[0236] 1.4.3 Sensor signal connection for automotive applications

[0237] Examples of flexible cables can be used as part of the automotive electrical system. The potentially high signal density allows electronic components in the vehicle to be supplied with both power and signals. One possible application is the transmission of sensor data to a control unit.

[0238] Another advantage is that the flexible waveguide can be adapted to the vehicle's contours, ensuring optimal use of the available space. This is particularly important given the increasing functional density of modern vehicles.

[0239] 2. Integration of RF components into a flexible waveguide

[0240] Fig. 14 shows a schematic sectional view of a flexible waveguide 100 along the wave propagation direction, wherein at least one radio-frequency (RF) component 140 is integrated into the flexible waveguide 100. The flexible waveguide 100 comprises a first metallization 102, a second metallization 104, a flexible substrate 106 arranged between the first metallization 102 and the second metallization 104, and at least one center conductor 108 (e.g., inner conductor) connected to the at least one radio-frequency component 140.

[0241] In embodiments, the flexible waveguide 100 can be the flexible waveguide described in section 1. For example, the center guide can have at least two striplines, wherein at least one of the at least two striplines comprises a superconducting material, and / or the center guide can be arranged asymmetrically with respect to the first metallization 102 and the second metallization 104. However, it should be noted that the flexible waveguide 100 is not limited to such embodiments. Rather, it is equally possible for the center guide to have only one stripline made of superconducting or non-superconducting material and / or for the center guide to be arranged symmetrically (i.e., centrally) with respect to the first metallization 102 and the second metallization 104.

[0242] In embodiments, the flexible waveguide can be designed as a ribbon cable.

[0243] In exemplary embodiments, multiple RF components (e.g., two or more RF components) can of course also be integrated. In this case, the RF components can each be connected to at least one center conductor.

[0244] RF components that can be integrated into printed circuit boards (stripline technology) can often be integrated into flexible waveguides. Any conductor material (e.g. copper, aluminum, gold, silver) or even superconducting materials (e.g. niobium, indium, lead, etc.) can be used. In addition, lossy materials can also be specifically applied during production; this can be used, for example, for attenuators or RF terminations. In order to integrate the components compactly into the flexible substrate, they can be arranged offset, as described below with reference to Figs. 15 to 18. This has the technical advantage, for example, of reducing crosstalk between the individual RF components. At the same time, the individual RF components are only arranged over a short section of the cable, which allows a compact arrangement to be realized.

[0245] Fig. 15 to 18 show schematic sectional views of the flexible waveguide 100 along the wave propagation direction, wherein several RF components 140 are integrated into the flexible waveguide 100 and are arranged offset from one another.

[0246] In embodiments, the RF components can be arranged offset from one another in the wave propagation direction of the flexible waveguide and / or perpendicular to the wave propagation direction, wherein in Figs. 15 to 18 it is assumed by way of example that the high-frequency components are arranged offset from one another in the wave propagation direction.

[0247] For example, the RF components may be arranged offset from one another according to a regular pattern, as shown in Figs. 15 and 16.

[0248] In detail, Fig. 15 shows a schematic sectional view of the flexible waveguide 100 along the wave propagation direction, wherein a plurality of RF components 140 are integrated into the flexible waveguide 100 and arranged offset from one another according to a regular pattern. In other words, Fig. 15 shows a schematic representation of a variant arrangement of the integrated RF components 140 in the flexible substrate 106.

[0249] Fig. 16 shows a schematic sectional view of the flexible waveguide 100 along the wave propagation direction, wherein a plurality of RF components 140 are integrated into the flexible waveguide 100 and arranged diagonally offset from one another. In other words, Fig. 16 shows a schematic representation of a diagonal arrangement variant of the integrated RF components 140 in the flexible substrate 106.

[0250] Of course, the RF components can also be adjusted according to a non-regular

[0251] Pattern (e.g., randomly) offset from one another, as shown in Fig. 17. In detail, Fig. 17 shows a schematic sectional view of the flexible waveguide 100 along the wave propagation direction, wherein a plurality of RF components 140 are integrated into the flexible waveguide 100, which are arranged offset from one another according to a non-regular pattern. In other words, Fig. 17 shows a schematic representation of a randomized arrangement variant of the integrated RF components 140 in the flexible substrate 106.

[0252] In addition, it is possible for the RF components 140 to be arranged in series with one another and / or to extend over the entire length of the flexible waveguide 100, as shown in Fig. 18.

[0253] In detail, Fig. 18 shows a schematic sectional view of the flexible waveguide 100 along the wave propagation direction, wherein a plurality of RF components 140 are integrated into the flexible waveguide 100, which are arranged in series with one another and / or extend over the entire length of the flexible waveguide 100. In other words, Fig. 18 shows a schematic representation of a variant arrangement of the integrated RF components in the flexible substrate, wherein a plurality of RF components are arranged in series or an RF component is integrated over the entire cable length.

[0254] In exemplary embodiments, the offset can therefore occur both regularly (see Figs. 15 and 16) and in a randomized arrangement (see Fig. 17). A regular offset allows symmetries of the arrangement to be exploited when designing the individual RF components. For example, it can be assumed that the individual RF components are each subject to comparable coupling / scattering effects. A randomized arrangement, on the other hand, can be used to specifically average the coupling / scattering effects between the individual RF components. The randomization can, for example, occur with regard to the length and / or width and / or position of the individual RF components along the respective line.

[0255] In exemplary embodiments, a serial arrangement of the individual RF components is possible (see Fig. 18, top). It is also possible to integrate a specific RF component over the entire cable length (see Fig. 18, bottom). This achieves the technical advantage that multi-stage operations, for example, multiple attenuation Z-filter stages, can be implemented particularly easily. In particular, filters with a higher filter order can also be implemented. In exemplary embodiments, the integration density can be significantly increased in all of the aforementioned examples by a suitable arrangement of the individual RF components relative to one another.

[0256] In embodiments, in addition to integrating all required RF components into a single flexible waveguide, it is also possible to produce individual modules that implement a single RF component.

[0257] In some embodiments, the RF components in the flexible waveguide, like the waveguide itself, can be flexible, bendable, and highly integrated. This allows for an efficient signal chain to be realized even in limited space. A further advantage of this type of component integration is that all components are always shielded by the cable structure.

[0258] 2.1 Preferred structure of the flexible waveguide

[0259] The arrangement variants shown and described can be implemented particularly advantageously in a flexible multi-core cable.

[0260] Suitable waveguides for high-frequency signals can be manufactured based on (polyimide) films or (polyimide) substrates coated with various metals (e.g., copper, niobium, aluminum, etc.). If the substrate is coated with superconducting materials (e.g., niobium or aluminum), superconducting cables can also be constructed. The basic idea of ​​the invention is to realize waveguides such as striplines with at least three metal layers.

[0261] If a flexible material such as thin polyimide films is used, the entire waveguide is flexible within certain limits and can be used and bent in a similar way to a cable.

[0262] Through the clever placement of vias at regular intervals, sufficiently high shielding attenuation can be achieved, so that even with adjacent waveguides, the decoupling is less than or equal to -60 dB. The via fences can be arranged in single, double, or n-row configurations to achieve even lower crosstalk. To achieve even higher signal integrity, the multi-row via fences can also be offset from one another; for example, by half a via grid. With clever dimensioning and sufficient manufacturing tolerances and capabilities, a very highly integrated and flexible cable with, for example, 100 waveguides per inch can be realized.

[0263] As already mentioned above, Fig. 2 shows the cross-section of an exemplary flexible cable. In the flexible cable shown, the center conductor was arranged such that the center conductor is closer to the lower shielding metallization than to the upper shielding metallization (so-called "asymmetrical structure"). In the asymmetrical structure, the layer thicknesses of the dielectrics are therefore selected differently. This achieves the technical advantage that a layer change or connector transition can be carried out more easily. Furthermore, the technical advantage is achieved that the adaptation of the characteristic impedance at the transition to a connector can be significantly improved.

[0264] As already mentioned above, Fig. 5 shows the cross-section of another example flexible cable. The cable shown uses more than three metal layers. The structure could, for example, correspond to the sequence of shielding - center conductor - shielding - center conductor - shielding - (...). Such an arrangement realizes multiple layers, which can further increase the integration density of the flexible cable.

[0265] 2.2 Implementation examples for individual RF components

[0266] 2.2.1 Filter

[0267] In embodiments, the RF component 140 may be a filter, as will be explained in more detail below with reference to Figs. 19a-d.

[0268] Figs. 19a and 19b each show a schematic sectional view through the flexible waveguide 100 along a plane parallel to the first and second metallizations, wherein the RF component 140 is a filter implemented by stub lines 142. In other words, Figs. 19a and 19b show two variants of integrated stub line filters.

[0269] As can be seen in Figs. 19a and 19b, the stub lines (strip lines) 142 can each be connected to the center conductor 108 at one end and be open at a second end. The stub lines 142 can be substantially straight and / or run parallel to the center conductor 108 at least in sections.

[0270] The flexible waveguide can have a plurality of vias 114 that run between the first metallization 102 and the second metallization 104 and connect them to one another. The plurality of vias 114 can be arranged in the form of via fences around the center conductor 108 and the stub lines 142. In Fig. 19a, it is assumed, by way of example, that the plurality of vias 114 (via fences) are arranged along two straight lines that run parallel to the center conductor 108 at a distance greater than the RF component, whereas in Fig. 19b it is assumed that the plurality of vias 114 (via fences) are forged closely to the center conductor 108 and the RF component. A filter characteristic can be changed by the different arrangement of the plurality of vias 114.

[0271] Fig. 19c shows a schematic sectional view through the flexible waveguide 100 along a plane parallel to the first and second metallizations, where the RF component 140 is a filter implemented by meandering stub lines 142. In other words, Fig. 19c shows an integrated stub line filter with meandering.

[0272] As can be seen in Fig. 19c, the stubs (striplines) 142 can each be connected to the center conductor 108 at one end and be open at a second end. The flexible waveguide can have a plurality of vias 114 that extend between and interconnect the first metallization 102 and the second metallization 104. The plurality of vias 114 can be arranged in the form of via fences around the center conductor 108 and the stubs 142.

[0273] Fig. 19d shows a schematic sectional view through the flexible waveguide 100 along a plane parallel to the first and second metallizations, where the RF component 140 is a filter implemented by a meandering stub 142. In other words, Fig. 19d shows an integrated stub filter with meandering and a short circuit as the terminating impedance.

[0274] As can be seen in Fig. 19d, the stub line (stripline) 142 can be connected at one end to the center conductor 108 and terminated at a second end, e.g., via a via connected to the first metallization and / or second metallization, such as one of the vias of the via fences 114. In embodiments, the filter can satisfy the desired frequency response.

[0275] In embodiments, the filter can be designed using stripline technology.

[0276] In exemplary embodiments, the filter requires little space.

[0277] In some examples, any inductance and capacitance can be realized using stub lines. This is achieved by appropriately dimensioning the line length and selecting the terminating impedance (open circuit or short circuit).

[0278] In embodiments, the short circuit can be realized both on the stub line and with connection to already existing grounded vias (see Figure Fig. 19d).

[0279] In exemplary embodiments, filters of any order can be implemented using stripline technology using the implemented reactances. The filters can be designed as stub filters (see Figs. 19a and 19b) or as coupled line filters.

[0280] In embodiments, miniaturization techniques such as meandering the lines (see Fig. 19c) or polygonal lines can be used to minimize the space requirements of the filters.

[0281] In embodiments, phase shifters and baluns can be implemented (e.g. additionally) via the realized reactances.

[0282] In embodiments, the structures can be integrated directly into the flexible waveguide.

[0283] In the examples shown, possible reflection points at connector transitions are eliminated.

[0284] In exemplary embodiments, a high integration density is enabled.

[0285] In embodiments, the RF component 140 may be an attenuator, as explained in more detail below with reference to FIGS. 20a and 20b. FIG. 20a shows a schematic sectional view through the flexible waveguide 100 along a plane parallel to the first and second metallizations, wherein the RF component 140 is an attenuator implemented by striplines, according to one embodiment.

[0286] Fig. 20b shows a schematic through the flexible waveguide of Fig. 20a transverse to the wave propagation direction, according to an embodiment.

[0287] In embodiments, the attenuator 140 can be connected in series between a first center conductor 108_1 and a second center conductor 108_2 and implemented using striplines (see Fig. 20a). In embodiments, the striplines can form resistive elements or act as resistive elements, e.g., by using more lossy materials for the striplines than for the center conductors and / or by adjusting the resistance of the striplines via dimensioning (e.g., width and / or height).

[0288] In embodiments, the striplines can be connected as a pi-element, a T-element or a cross-element.

[0289] In the embodiment shown in Figs. 20a and 20b, the attenuator 140 may comprise five striplines 142_1-142_5, wherein a first stripline 142_1 may be connected in series between the first center conductor 108_1 and the second center conductor 108_2, wherein a second stripline 142_2 is connected in series between the first center conductor 108_1 and at least one via of a plurality of vias 114 connected to the first metallization 120 and / or second metallization 104 (e.g.electrically), wherein a third stripline 142_3 is connected in series between the first center conductor 108_1 and at least one via of the plurality of vias 114, wherein a fourth stripline 142_4 is connected in series between the second center conductor 108_2 and at least one via of the plurality of vias 114, and wherein a fifth stripline 142_5 is connected in series between the second center conductor 108_1 and at least one via of the plurality of vias 114.

[0290] As can be seen in Figs. 20a and 20b, at least those vias of the plurality of vias 114 that are arranged in the region of the attenuator 140 can be connected to one another via respective ground planes 144. In other words, Fig. 20a shows a schematic plan view of an attenuator 140 using stripline technology in a flexible substrate 106, designed as a symmetrical pi-element, while Fig. 20b shows a schematic cross-sectional view of the attenuator 140 in the flexible substrate 106.

[0291] In embodiments, the attenuator can be designed using stripline technology.

[0292] In embodiments, the attenuator can be adapted to be low-reflection.

[0293] In embodiments, the attenuator may have a low frequency response.

[0294] In embodiments, the attenuator may have a desired attenuation value.

[0295] In exemplary embodiments, the attenuator can be designed with different topologies, such as a pi-element, T-element, or cross-element. To create resistive elements, materials with higher losses (e.g., a titanium-tungsten alloy) can be introduced into the waveguide, e.g., by sputtering. Alternatively or additionally, the resistance can be adjusted as desired via the geometric dimensions. Another possible implementation of resistive elements is the use of very thin layers of an electrical conductor.

[0296] In embodiments, the attenuator can be integrated directly into the flexible waveguide.

[0297] In some embodiments, the attenuator can be extended over the entire length of the conductor. This allows Joule heat to be dissipated more efficiently.

[0298] 2.2.3 Directional coupler

[0299] In embodiments, the RF component 140 may be a directional coupler, as will be explained in more detail below with reference to Figs. 21a and b and 22a and b.

[0300] In detail, Fig. 21a shows a schematic sectional view through the flexible waveguide 100 along a plane that runs parallel to the first and second metallization 102, 104, wherein the RF component 140 is a directional coupler implemented by striplines 142_1 and 142_2, while Fig. 21b shows a schematic sectional view through the flexible waveguide 100 transverse to the wave propagation direction, according to one embodiment.

[0301] As can be seen in Figs. 21a and 21b, the directional coupler can comprise two interconnected striplines 142_1 and 142_2. The two interconnected striplines 142_1 and 142_2 can run parallel to each other in the flexible substrate 106.

[0302] In embodiments, the at least two striplines 142_1 and 142_ coupled to each other can each be connected to at least one center conductor of the flexible waveguide 100.

[0303] In embodiments, the two interconnected striplines 142_1 and 142_2 can be arranged in different planes in the flexible substrate 106 (see Fig. 21b). For example, the two interconnected striplines can be arranged one above the other in the flexible substrate (e.g., with respect to a straight line 146 that is perpendicular to the first metallization 102 and / or second metallization 104, or in other words, so that the two interconnected striplines 142_1 and 142_2 intersect the straight line 148 in different positions).

[0304] As shown in Fig. 21a, in embodiments, the two interconnected striplines 142_1 and 142_2 can have a meandering course (e.g., the same course) at least in a coupled section. Of course, the two interconnected striplines 142_1 and 142_2 can also have a straight course or a polygonal course.

[0305] Fig. 22a shows a schematic sectional view through the flexible waveguide 100 along a plane that runs parallel to the first and second metallizations 102, 104, wherein the RF component 140 is a directional coupler implemented by sawtooth-shaped striplines 142_1 and 142, while Fig. 22b shows a schematic sectional view through the flexible waveguide 100 transverse to the wave propagation direction, according to one embodiment. Compared to the embodiment shown in Figs. 21a and 21b, the two mutually coupled striplines 142_1 and 142_2 run in the same plane in the embodiment shown in Figs. 22a and 22b. Thus, the two mutually coupled striplines 142_1 and 142_2 can be arranged next to one another in the flexible substrate 106 (e.g.with respect to a straight line 148 which runs parallel to the first metallization and / or second metallization, or in other words, so that the two striplines 142_1 and 142_2 coupled to each other intersect the straight line 148 in different positions).

[0306] In order to increase coupling between the striplines 142_1 and 142_2, the two coupled striplines 142_1 and 142_2 can have corresponding sawtooth shapes at least in a coupled section, as can be seen in Fig. 22a.

[0307] In other words, Fig. 21a shows a top view of the inner layer of a possible design of an integrated meandering coupler, while Fig. 21b shows a cross-section of a coupler with broadside coupling. Fig. 22a shows a top view of the inner layer of a possible design of an integrated sawtooth coupler, while Fig. 22b shows a cross-section of a coupler with sawtooth coupling.

[0308] In embodiments, the directional coupler can be designed using stripline technology.

[0309] In embodiments, the directional coupler may have desired properties such as coupling factor, coupling attenuation, matching, frequency range, etc.

[0310] In embodiments, the directional coupler may have a small space requirement.

[0311] In embodiments, the coupled lines can also be designed one above the other with broadside coupling (see Figures 21a and 21b) or by means of sawtooth coupling (see Figures 22a and 22b) in order to enable sufficient coupling even with small metallization thicknesses.

[0312] In some embodiments, miniaturization techniques, such as meandering the lines or polygonal lines, can be used to reduce (or even minimize) the space requirements of the filters. In some embodiments, the structures of the directional coupler can be integrated directly into the flexible waveguide.

[0313] In the exemplary embodiments, possible reflection points at connector transitions are eliminated.

[0314] Examples of implementations enable a high integration density.

[0315] 2.2.4 Transformer

[0316] In embodiments, the RF component 140 may be a transformer, as will be explained in more detail below with reference to Fig. 23.

[0317] Fig. 23 shows a schematic sectional view through the flexible waveguide 100 along a plane parallel to the first and second metallization, wherein the RF component 140 is a transformer implemented by striplines 142_1 and 142_2.

[0318] As can be seen in Fig. 23, the transformer may comprise a first loop-shaped stripline 142_1 and a second loop-shaped stripline 142_2 integrated / embedded in the flexible substrate 106, wherein the first loop-shaped stripline 142_1 and the second loop-shaped stripline 142_2 are arranged in different planes of the flexible substrate 106. For example, the two loop-shaped striplines may be arranged one above the other in the flexible substrate (e.g., with respect to a straight line perpendicular to the first metallization and / or second metallization).

[0319] In embodiments, a first end of the first looped stripline 142_1 may be connected to a first center conductor of the flexible waveguide 100, while a first end of the second looped stripline 142_2 may be connected to a second center conductor of the flexible substrate.

[0320] In embodiments, a second end of the first looped stripline 142_1 may be connected to the first metallization and / or second metallization of the flexible waveguide via a first via 143_1, while a second end of the second looped stripline 142_2 may be connected to the first metallization and / or second metallization of the flexible waveguide via a second via 143_2. In other words, Fig. 23 shows an integrated transformer / transformer with adjustable impedance ratio.

[0321] In embodiments, the transformer can be designed using stripline technology.

[0322] In embodiments, the transformer may have low reflections.

[0323] In embodiments, a desired impedance ratio of the transformer can be adjustable.

[0324] In embodiments, the transformer may have a small space requirement.

[0325] In embodiments, miniaturization techniques, such as meandering the lines, can be used to reduce (or even minimize) the space required by the transformer.

[0326] In exemplary embodiments, a desired transmission ratio can be set via the winding ratio.

[0327] 2.2.5 Power divider

[0328] In embodiments, the RF component 140 may be a power divider, as will be explained in more detail below with reference to Figs. 24a to 24c.

[0329] Fig. 24a to 24c each show a schematic sectional view through the flexible waveguide 100 along a plane that runs parallel to the first and second metallization, wherein the RF component 140 is a power divider implemented by at least one stripline.

[0330] In embodiments, the power divider implemented by at least one stripline may be integrated into the flexible substrate 106 of the flexible waveguide 100.

[0331] In embodiments, the power splitter can be connected on the input side to a first center conductor 108_1 of the flexible waveguide, while the power splitter can be connected on the output side to a second center conductor 108_2 and a third center conductor 108_3 of the flexible waveguide. The first center conductor 108_1, the second center conductor 108_2, and the third center conductor 108_3 can each have a characteristic impedance Z0.

[0332] Fig. 21a shows an embodiment in which the power divider is implemented by a stripline 142.

[0333] Here, a first end of the stripline 142 can be connected to the first center conductor 108_1, wherein a second end of the stripline 142 can be connected to the second center conductor 108_2 and the third center conductor 108_3.

[0334] In embodiments, the stripline 142 may have a length that is one-quarter of a wavelength of a signal carried in the first center conductor 108_1.

[0335] In embodiments, the stripline 142 may have a line characteristic impedance equal to a quotient of a line characteristic impedance ZO and the square root of two.

[0336] Fig. 21b shows an embodiment in which the power divider is implemented by a first stripline 142_1 and a second stripline 142_2.

[0337] The first stripline 142_1 may be connected in series between the first center conductor 108_1 and the second center conductor 108_2, wherein the second stripline 142_2 is connected in series between the first center conductor 108_1 and the third center conductor 108_2.

[0338] In embodiments, the first stripline 142_1 and the second stripline 142_2 may each have a length that is one-quarter of a wavelength of a signal carried in the first center conductor 108_1.

[0339] In embodiments, the first stripline 142_1 and the second stripline 142_2 may each have a line characteristic impedance equal to a product of a line characteristic impedance ZO and the square root of two.

[0340] Fig. 21c shows an embodiment in which the power divider is implemented by a first stripline 142_1 and a second stripline 142_2, wherein the first stripline 142_1 and the second stripline 142_2 are connected on the output side via a resistor implemented in stripline technology (e.g., of size 2Z0).

[0341] The first stripline 142_1 may be connected in series between the first center conductor 108_1 and the second center conductor 108_2, wherein the second stripline 142_2 is connected in series between the first center conductor 108_1 and the third center conductor 108_2.

[0342] In embodiments, the first stripline 142_1 and the second stripline 142_2 can each have a semicircular shape, as shown in Fig. 24c. However, embodiments are not limited to such a stripline shape. Rather, the striplines can also have a different shape, for example, a straight or slightly curved shape.

[0343] In embodiments, the first stripline 142_1 and the second stripline 142_2 may each have a length that is one-quarter of a wavelength of a signal carried in the first center conductor 108_1.

[0344] In embodiments, the first stripline 142_1 and the second stripline 142_2 may each have a line characteristic impedance equal to a product of a line characteristic impedance Z0 and the square root of two.

[0345] In other words, Fig. 24a shows a first variant of an integrated λ / 4 power divider, while Fig. 24b shows a second variant of an integrated λ / 4 power divider, and while Fig. 24c shows an integrated Wilkinson power divider.

[0346] In embodiments, the power divider can be designed using stripline technology.

[0347] In embodiments, the power divider may have low reflections.

[0348] In embodiments, the power divider may provide a desired division ratio.

[0349] In embodiments, the power divider may have a small footprint. In embodiments, miniaturization techniques, such as meandering the lines, may be used to reduce (or even minimize) the footprint of the power divider.

[0350] In some embodiments, lossy materials can be incorporated into the waveguide, e.g., by sputtering, if resistive elements are required. Another possible implementation of resistive elements is the use of very thin layers of an electrical conductor.

[0351] In exemplary embodiments, various types of power dividers can be implemented. For example, a / 4 power divider (see Figs. 24a and 24b) or a Wilkinson power divider (see Fig. 24c).

[0352] In some embodiments, the division ratio can be either symmetrical—even power distribution at a ratio of 1:1 (shown as an example in Figs. 24a to 24c)—or asymmetrical. With an asymmetrical division ratio, the characteristic impedance of the ¼-wave transformers changes accordingly (see Figs. 24b and 24c).

[0353] 2.3 Possible application

[0354] Quantum computers with superconducting qubits require highly precise and low-noise control of the qubits. The necessary connections of the control lines should be placed as close as possible to the quantum chip. This is not easily feasible, as various RF components must be integrated into the signal chain. To overcome this, it is advantageous to integrate the RF components directly into the control lines. This also massively reduces the number of external components and thus also reduces the susceptibility to errors in the quantum system's design.

[0355] To date, coaxial semi-ridged cables have been commonly used. The RF components used in these applications have so far been external coaxial. Due to the space required, the number of qubits that can be realized is limited (to three-digit values). To achieve even higher qubit counts, the current integration density provided by semi-rigid cables and external RF components is insufficient.

[0356] Embodiments of the flexible waveguide described herein with at least one integrated radio-frequency component can, however, be used for signal routing in a quantum computer 300 between quantum processor 302 and signal generator and / or signal evaluator 304, as shown in Fig. 12. Embodiments of the flexible waveguide described herein make it possible to increase the integration density and thus realize higher qubit numbers.

[0357] 3. Further implementation examples

[0358] Although some aspects have been described in the context of a device, it should be understood that these aspects also represent a description of the corresponding method, so that a block or component of a device can also be understood as a corresponding method step or as a feature of a method step. Analogously, aspects described in the context of or as a method step also represent a description of a corresponding block, detail, or feature of a corresponding device. Some or all of the method steps may be performed by (or using) a hardware apparatus, such as a microprocessor, a programmable computer, or an electronic circuit. In some embodiments, some or more of the key method steps may be performed by such an apparatus.

[0359] The above-described embodiments are merely illustrative of the principles of the present invention. It is understood that modifications and variations of the arrangements and details described herein will be apparent to others skilled in the art. Therefore, it is intended that the invention be limited only by the scope of the following claims and not by the specific details presented in the description and explanation of the embodiments herein.

[0360] Bibliography

[0361] [1] Krinner, S., Storz, S., Kurpiers, P. et al. “Engineering cryogenic setups for 100-qubit scale superconducting circuit systems” - EPJ Quantum Technology 6(1)

[0362] [2] David B Tuckerman, Michael C Hamilton, David J Reilly, Rujun Bai, George A Hernandez, John M Hornibrook, John A Sellers, Charles D Ellis, “Flexible superconducting Nb transmission lines on thin film polyimide for quantum computing applications”, Superconductor Science and Technology 29 (2016) 084007 (12pp), DOI: 10.1088 / 0953-2048 / 29 / 8 / 084007.

[0363] [3] Shuna Wang, Wenbing Jiang, Huiqin Yu et al. “Functional flexible cables for cryogenic quantum systems” - 2022 IEEE 15th Workshop on Low Temperature Electronics (WOLTE)

[0364] [4] Page "List of transition temperatures of chemical elements." In: Wikipedia - The Free Encyclopedia. Edited on: July 4, 2022, 10:16 UTC. URL: https: / / de.wi kipedia.org / w / index.php?title=Liste_der_Sprungtemperaturen_che mischer_Elemente&oldid=224223235 (Accessed: September 22, 2023, 12:39 UTC)

Claims

Patent claims 1. Flexible waveguide (100), comprising: a first metallization (102), a second metallization (104), a flexible substrate (104) arranged between the first metallization (102) and the second metallization (104), at least one radio frequency component (140) embedded in the substrate (104) and connected to at least one center conductor (108) of the flexible waveguide (100).

2. Flexible waveguide (100) according to claim 1, wherein the at least one high-frequency component (140) is at least two high-frequency components (140), wherein the at least two high-frequency components (140) are arranged offset from one another.

3. Flexible waveguide (100) according to claim 2, wherein the at least two high-frequency components (140) are arranged offset from one another in the wave propagation direction of the flexible waveguide (100) and / or perpendicular to the wave propagation direction.

4. Flexible waveguide (100) according to one of claims 2 to 3, wherein the at least two high-frequency components (140) are at least three high-frequency components (140), wherein the at least three high-frequency components (140) are arranged offset from one another according to a regular pattern, or wherein the at least three high-frequency components (140) are arranged offset from one another according to a non-regular pattern.

5. Flexible waveguide (100) according to one of claims 2 to 4, wherein at least two center conductors (108) are embedded in the flexible substrate (104), and wherein the at least two radio frequency components (140) are each connected to a center conductor (108).

6. Flexible waveguide (100) according to claim 1, wherein the at least one high-frequency component (140) is at least two high-frequency components (140), and wherein the at least two high-frequency components (140) are arranged in series with one another.

7. Flexible waveguide (100) according to one of claims 1 to 6, wherein a high-frequency component (140) of the at least one high-frequency component (140) is a filter.

8. The flexible waveguide (100) of claim 7, wherein the high frequency component (140) includes at least one stub (142) connected at a first end to the at least one center conductor (108).

9. The flexible waveguide (100) of claim 8, wherein the at least one stub (142) is open at a second end, or wherein the at least one stub (142) is terminated at the second end.

10. Flexible waveguide (100) according to claim 9, wherein the at least one stub (142) is terminated at the second end by at least one via (114) connected to the first metallization (102) and / or second metallization (104).

11. Flexible waveguide (100) according to one of claims 8 to 10, wherein at least a portion of the at least one stub line (142) runs parallel to the at least one center conductor (108), or wherein at least a portion of the at least one stub line (142) has a meandering or polygonal shape.

12. Flexible waveguide (100) according to one of claims 1 to 11, wherein a high-frequency component (140) of the at least one high-frequency component (140) is an attenuator.

13. The flexible waveguide (100) of claim 12, wherein the at least one center conductor (108) comprises a first center conductor (108_1) and a second center conductor (108_2), wherein the attenuator is connected in series between the first center conductor (108_1) and the second center conductor (108_2).

14. Flexible waveguide (100) according to claim 13, wherein the attenuator comprises at least a first resistive element (142_1) and a second resistive element (142_2), wherein the first resistive element (142_1) is connected in series between the first center conductor (108_1) and the second center conductor (108_2), wherein the second resistive element (142_2) is connected in series between the first center conductor (108_1) and a first via (114) connected to the first metallization (102) and / or second metallization (104).

15. The flexible waveguide (100) of claim 14, wherein the attenuator comprises a third resistive element (142_3), the third resistive element (142_3) being connected in series between the first center conductor (108_1) and a second via (114) connected to the first metallization (102) and / or second metallization (104).

16. The flexible waveguide (100) of claim 14, wherein the attenuator comprises a fourth resistive element (142_4) and a fifth resistive element (142_5), wherein the fourth resistive element (142_4) is connected between the second center conductor (108_2) and a third via (114) connected to the first metallization (102) and / or second metallization (104), wherein the fifth resistive element (142_5) is connected between the second center conductor (108_2) and a fourth via (114) connected to the first metallization (102) and / or second metallization (104).

17. Flexible waveguide (100) according to one of claims 14 to 16, wherein the resistive elements are each implemented by a stripline having a higher insertion loss than the first center conductor (108_1) and / or the second center conductor (108_2).

18. Flexible waveguide (100) according to claim 17, wherein the striplines are connected to the first center conductor (108_1) and / or the second center conductor (108_2).

19. Flexible waveguide (100) according to one of claims 1 to 18, wherein a high-frequency component (140) of the at least one high-frequency component (140) is a directional coupler.

20. Flexible waveguide (100) according to claim 19, wherein the directional coupler comprises two striplines (142_1, 142_2) coupled to one another.

21. Flexible waveguide (100) according to claim 20, wherein the two mutually coupled striplines (142_1, 142_2) run parallel to each other in the flexible substrate (104).

22. Flexible waveguide (100) according to one of claims 20 and 21, wherein the two mutually coupled striplines (142_1, 142_2) are arranged in different planes in the flexible substrate (104).

23. Flexible waveguide (100) according to claim 22, wherein the two strip lines (142_1, 142_2) coupled to one another have a meandering or polygonal course at least in a coupled section.

24. Flexible waveguide (100) according to one of claims 20 and 21, wherein the two mutually coupled striplines (142_1, 142_2) are arranged in the same plane in the flexible substrate (104).

25. Flexible waveguide (100) according to claim 24, wherein the two mutually coupled striplines (142_1, 142_2) have corresponding sawtooth shapes at least in a coupled section.

26. Flexible waveguide (100) according to one of claims 20 to 25, wherein a first stripline (142_1) of the two mutually coupled striplines (142_1, 142_2) is connected to at least a first center conductor (108_1) of the at least one center conductor (108), wherein a second stripline (142_2) of the two mutually coupled striplines (142_1, 142_2) is connected to at least a second center conductor (108_2) of the at least one center conductor (108).

27. Flexible waveguide (100) according to one of claims 20, wherein each of the two mutually coupled striplines (142_1, 142_2) is connected to at least one center conductor (108).

28. Flexible waveguide (100) according to one of claims 1 to 27, wherein a high-frequency component (140) of the at least one high-frequency component (140) is a transformer.

29. The flexible waveguide (100) of claim 28, wherein the transformer comprises a first loop-shaped stripline (142_1) and a second loop-shaped stripline (142_2).

30. Flexible waveguide (100) according to claim 29, wherein the first loop-shaped stripline (142_1) and the second loop-shaped stripline (142_2) are arranged in different planes of the flexible substrate (104).

31. Flexible waveguide (100) according to one of claims 29 and 30, wherein the first loop-shaped stripline (142_1) is connected to a first center conductor (108_1) of the at least one center conductor (108), wherein the second loop-shaped stripline (142_2) is connected to a second center conductor (108_2) of the at least one center conductor (108).

32. Flexible waveguide (100) according to claim 31, wherein the first loop-shaped stripline (142_1) is connected in series between the first center conductor (108_1) and a first via (143_1) which is connected to the first metallization (102) and / or second metallization (104), wherein the second loop-shaped stripline (142_2) is connected in series between the second center conductor (108_2) and a second via (143_2) which is connected to the first metallization (102) and / or second metallization (104).

33. Flexible waveguide (100) according to one of claims 1 to 32, wherein a high-frequency component (140) of the at least one high-frequency component (140) is a power divider.

34. Flexible waveguide (100) according to claim 33, wherein the power divider is implemented using stripline technology.

35. Flexible waveguide (100) according to one of claims 33 to 34, wherein the power splitter is connected on the input side to a first center conductor (108_1) of the at least one center conductor (108), wherein the power splitter is connected on the output side to a second center conductor (108_2) and a third center conductor (108_3) of the at least one center conductor (108).

36. The flexible waveguide (100) of claim 35, wherein the power splitter comprises a stripline (142), a first end of the stripline (142) being connected to the first center conductor (108_1), and a second end of the stripline (142) being connected to the second center conductor (108_2) and the third center conductor (108_3).

37. Flexible waveguide (100) according to claim 36, wherein the stripline (142) has a length which is one quarter of a wavelength of a signal carried in the first center conductor (108_1), and / or wherein the stripline (142) has a line characteristic impedance which is equal to a quotient of a line characteristic impedance ZO and the square root of two.

38. Flexible waveguide (100) according to one of claims 33 to 34, wherein the power splitter comprises a first stripline (142_1) and a second stripline (142_2), wherein the first stripline (142_1) is connected in series between the first center conductor (108_1) and the second center conductor (108_2), and wherein the second stripline (142_2) is connected in series between the first center conductor (108_1) and the third center conductor (108_3).

39. Flexible waveguide (100) according to claim 38, wherein the first stripline (142_1) and the second stripline (142_2) each have a length which is one quarter of a wavelength of a signal carried in the first center conductor (108_1), and / or wherein the first stripline (142_1) and the second stripline (142_2) each have a line characteristic impedance which is equal to a product of a line characteristic impedance ZO and the square root of two.

40. The flexible waveguide (100) of any one of claims 33 to 34, wherein the power splitter comprises a first stripline (142_1) and a second stripline (142_2), wherein the first stripline (142_1) is connected in series between the first center conductor (108_1) and the second center conductor (108_2), and wherein the second stripline (142_2) is connected in series between the first center conductor (108_1) and the third center conductor (108_3).

41. Flexible waveguide (100) according to claim 40, wherein the first stripline (142_1) and the second stripline (142_2) are connected on the output side via a resistor implemented in stripline technology.

42. Flexible waveguide (100) according to claim 41, wherein the first stripline (142_1) and the second stripline (142_2) each have a length which is one quarter of a wavelength of a signal carried in the first center conductor (108_1), and / or wherein the first stripline (142_1) and the second stripline (142_2) each have a line characteristic impedance which is equal to a product of a line characteristic impedance ZO and the square root of two.

43. Quantum computer (300), having the following features: a quantum processor (302), a signal generator and / or signal evaluator (304), and at least one flexible waveguide (100) according to one of claims 1 to 42 for signal transmission between the quantum processor (302) and the signal generator and / or signal evaluator (304).

44. Quantum computer according to claim 43, wherein the quantum processor (302) is configured to operate at a cryogenic temperature, and / or wherein the signal generator and / or signal evaluator (304) is configured to operate at a cryogenic temperature or a non-cryogenic temperature.

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