Detachable connector for a flexible waveguide

Abstract

Exemplary embodiments provide a detachable connector for connecting a flexible waveguide to a rigid substrate (e.g., a printed circuit board) [e.g., electrically and / or mechanically]. The detachable connector is designed to be applied to the flexible waveguide [e.g., mechanically] and to be connected to a mating connector that is in contact with the substrate [e.g., mechanically]. The detachable connector is designed to exert a compressive force on at least one contact surface of the flexible waveguide when the detachable connector is connected to the mating connector or in a state connected to the mating connector [e.g., when the detachable connector is connected to the mating connector], in order to press the at least one contact surface onto a mating contact surface of the substrate.

Description

[0001] Embodiments of the present invention relate to a detachable connector for connecting a flexible waveguide to a substrate, such as a printed circuit board. Some embodiments relate to miniaturized detachable radio-frequency connectors for contacting highly integrated flexible waveguides to rigid substrates.

[0002] In cryogenic applications, such as quantum computers with superconducting qubits, commercially available coaxial waveguides are currently used to carry RF signals [1]. Conventionally, such coaxial cables are equipped with standard connectors (e.g., SMA, G3PO, etc.) for transmitting signals within the quantum computer. In particular, with increasing performance due to the increasing number of qubits, the number of cables and connectors required for manipulating and reading the qubits in the cryostat increases. However, since the spatial capacity of cryostats is limited, the number of cables is also limited.

[0003] Initial approaches to replacing coaxial lines with flexible waveguides have already been identified. Examples of flexible waveguides with superconducting inner conductors are described in [2]. However, such waveguides are intended to be firmly bonded or soldered to a chip.

[0004] Furthermore, flexible cables with an integrated low-pass filter are known from [3]. [5] describes a connection scheme for connecting two flexible superconducting stripline cables.

[0005] The present invention is therefore based on the object of creating a concept which makes it possible to create a detachable direct contact between flexible waveguides and a rigid substrate, which ensures reliable signal transmission even at very low temperatures.

[0006] This problem is solved by the independent patent claims.

[0007] Advantageous further developments can be found in the dependent patent claims.

[0008] Embodiments provide a detachable connector for [e.g. electrically and / or mechanically] connecting a flexible waveguide to a [e.g. rigid] substrate [e.g. printed circuit board], wherein the detachable connector is designed to be applied to the flexible waveguide [e.g. mechanically] and to be connected to a mating connector that bears against the substrate [e.g. mechanically], wherein the detachable connector is designed to exert a compressive force on at least one connection surface of the flexible waveguide when connecting the detachable connector to the mating connector or in a state connected to the mating connector [e.g. when the detachable connector is connected to the mating connector] in order to press the at least one connection surface onto a mating connection surface of the substrate.

[0009] In embodiments, the compressive force acts perpendicularly on the at least one connection surface.

[0010] In embodiments, the compressive force acts transversely to a longitudinal axis of the flexible waveguide.

[0011] In embodiments, the detachable connector is configured to be applied to a first side of the flexible waveguide that is opposite a second side of the flexible waveguide that has the at least one [e.g., electrical] connection surface of the flexible waveguide.

[0012] In embodiments, the mating connector abuts the substrate on a first side opposite a second side of the substrate having the at least one mating connection surface.

[0013] In embodiments, the detachable connector comprises a housing and at least one pressure plate connected to the housing via at least one spring element, wherein the detachable connector is configured to be applied to the flexible waveguide via the pressure plate.

[0014] In embodiments, when connecting the detachable connector to the mating connector or in the state connected to the mating connector, the at least one spring can be tensioned in order to exert the compressive force on the at least one connection surface of the flexible waveguide.

[0015] In embodiments, the at least one pressure plate is exactly one pressure plate, wherein the pressure plate is connected to the housing via exactly one spring element or via a plurality of spring elements.

[0016] In embodiments, the at least one pressure plate is a plurality of pressure plates, wherein each of the plurality of pressure plates is connected to the housing via at least one spring element.

[0017] In embodiments, the at least one spring element is a compression spring, a disc spring, a wave spring, a straight flat spring or a stamped and bent part.

[0018] In embodiments, the detachable connector comprises a housing and an elastic layer connected to the housing, wherein the detachable connector is configured to be applied to the flexible waveguide via the elastic layer.

[0019] In embodiments, when connecting the detachable connector to the mating connector or in the state connected to the mating connector, the elastic layer can be compressed in order to exert the compressive force on the at least one connection surface of the flexible waveguide.

[0020] In embodiments, the elastic layer is elastic at cryogenic temperatures [e.g., at temperatures below 1 K, in particular at a temperature of 10 mK].

[0021] In embodiments, the elastic layer comprises indium or a photoresist [e.g. SU-8].

[0022] In embodiments, the detachable connector is designed to be connected to the mating connector via a detachable connection.

[0023] In embodiments, the detachable connection is a screw connection [e.g. by means of screws].

[0024] In embodiments, the detachable connection is a clamping connection [e.g. by means of clamping elements].

[0025] In embodiments, a material of the clamping elements has a higher coefficient of thermal expansion (CTE) than a material of the housing.

[0026] For example, clamping elements of the clamping connection can comprise brass, whereby the detachable connector comprises copper at least in the area of ​​the clamping elements.

[0027] For example, clamping elements of the clamping connection can comprise aluminum, whereby the detachable connector comprises copper at least in the area of ​​the clamping elements.

[0028] For example, clamping elements of the clamping connection can comprise brass, whereby the detachable connector comprises molybdenum (Mo) at least in the area of ​​the clamping elements.

[0029] For example, clamping elements of the clamping connection can comprise aluminum, whereby the detachable connector comprises molybdenum (Mo) at least in the area of ​​the clamping elements.

[0030] In embodiments, the detachable connector comprises at least one mechanical [e.g., protruding; projecting from a plane] alignment element, wherein the mechanical alignment element is configured to effect alignment between the detachable connector and the flexible waveguide upon application of the detachable connector to the flexible waveguide by connecting the mechanical alignment element to a mating alignment element of the flexible waveguide.

[0031] In embodiments, the mechanical alignment element is a pin [e.g., or web], wherein the alignment counter element is a cavity corresponding to the pin.

[0032] In embodiments, the mechanical alignment element is a cavity, wherein the alignment counter element is a pin corresponding to the cavity.

[0033] In embodiments, the detachable connector has at least one opening, wherein the opening is arranged such that when the detachable connector is applied to the flexible waveguide and the detachable connector is connected to the mating connector through the opening, a first optical marking [e.g. crosshairs, line] of the flexible waveguide and [e.g. simultaneously] a second optical marking [e.g. crosshairs, line] of the substrate are visible as soon as the detachable connector, the waveguide and the substrate are correctly aligned with each other.

[0034] In embodiments, the detachable connector has at least a first optical marking [e.g., crosshairs, line], the first optical marking being arranged such that when the detachable connector is applied to the flexible waveguide and the detachable connector is connected to the mating connector, the first optical marking is arranged in line with a second optical marking [e.g., crosshairs, line] of the flexible waveguide and [e.g., simultaneously] a third optical marking [e.g., crosshairs, line] of the substrate as soon as the detachable connector, the waveguide and the substrate are correctly aligned with one another.

[0035] Further embodiments provide a detachable connection system comprising a detachable connector according to one of the embodiments described herein and a mating connector configured to be applied to the substrate.

[0036] Further embodiments provide a flexible waveguide having 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, at least one center conductor embedded in the flexible substrate, and at least one connection surface arranged in a plane of the first metallization or the second metallization and exposed, wherein the at least one connection surface is connected to the at least one center conductor.

[0037] In embodiments, the at least one connection surface is insulated from the first metallization [e.g. electrically].

[0038] In embodiments, the at least one center conductor is connected to the at least one connection surface via at least one via.

[0039] In embodiments, the flexible waveguide comprises a plurality of vias interconnecting the first metallization and the second metallization, wherein the plurality of vias surround the at least one center conductor and the at least one pad.

[0040] In embodiments, the at least one center conductor has a first center conductor and a second center conductor, wherein the at least one connection surface has a first connection surface and a second connection surface, wherein the first connection surface and the second connection surface are arranged in a plane of the first metallization and are insulated from the first metallization [e.g. electrically], wherein the first connection surface is connected to the first center conductor and the second connection surface is connected to the second center conductor [e.g. electrically].

[0041] In embodiments, the flexible waveguide comprises 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.

[0042] In embodiments, the first terminal surface and the second terminal surface are arranged adjacent to one end of the flexible waveguide.

[0043] In embodiments, the first pad [and / or an associated first via] and the second pad [and / or an associated second via] have different distances from the end of the waveguide [ie, are offset from each other].

[0044] This has the technical effect of reducing crosstalk between the connection surfaces by 30 / 50 / 70 dB (depending on the specific geometry).

[0045] Further embodiments provide a cable [in particular a ribbon cable] with a detachable connector according to one of the embodiments described herein and a flexible waveguide according to one of the embodiments described herein.

[0046] Further embodiments provide quantum computers with a quantum processor, a signal generator and / or signal evaluator, and at least one detachable connector according to one of the embodiments described herein, a flexible waveguide according to one of the embodiments described herein, or a cable according to one of the embodiments described herein for signal transmission between the quantum processor and the signal generator and / or signal evaluator.

[0047] In embodiments, the substrate is a substrate of the quantum processor or the signal generator and / or signal evaluator.

[0048] In embodiments, the quantum processor is configured to operate at a cryogenic temperature [e.g., a temperature of less than 1 K].

[0049] 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].

[0050] Embodiments of the detachable connector described herein enable highly integrated waveguides to be connected to a rigid substrate. The detachable connector enables the conductors to be mechanically, electrically, and / or thermally connected to the substrate. Embodiments of the detachable connector enable fine structures to be connected to one another, thereby enabling high integration density. Embodiments of the detachable connector meet high requirements for mechanical alignment and homogeneous pressure distribution. Embodiments of the detachable connector can be used in a wide temperature range because the detachable connector ensures correct alignment and homogeneity of the pressure distribution over a wide temperature range. Embodiments of the detachable connector are RF connectors that enable low-reflection signal transmission with low crosstalk.

[0051] 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.

[0052] For example, the flexible waveguide can be configured as a ribbon cable. In particular, the flexible waveguide can have a plurality of center conductors.

[0053] 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.

[0054] In embodiments, the first superconducting material and the second superconducting material are two different materials.

[0055] 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.

[0056] In embodiments, the non-superconducting material does not exhibit superconducting properties at any temperature.

[0057] In embodiments, the superconducting material exhibits superconducting properties at temperatures below a material-specific transition temperature.

[0058] In embodiments, the superconducting material may be one of the following materials: niobium, aluminum, lead, indium, zinc, tantalum, or niobium nitride.

[0059] In embodiments, the non-superconducting material may be one of the following materials: copper, nickel, gold, or silver.

[0060] In embodiments, the at least two strip lines run parallel [e.g., with a constant distance] to each other.

[0061] In embodiments, the at least two strip lines are connected to each other [e.g., mechanically and / or electrically].

[0062] In embodiments, the at least two striplines are directly [ie without an adhesion layer and / or without a diffusion barrier] [mechanically and / or electrically] connected to one another.

[0063] In embodiments, at least two striplines are connected to one another [mechanically and / or electrically] 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)].

[0064] 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.

[0065] 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.

[0066] 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.

[0067] For example, the first stripline may comprise copper, the second stripline may comprise niobium, and the third stripline may comprise copper.

[0068] 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.

[0069] For example, the second stripline may comprise niobium, the first stripline may comprise copper, and the third stripline may comprise niobium.

[0070] In embodiments, the second stripline is embedded between the first stripline and the third stripline.

[0071] In embodiments, the first stripline is embedded between the second stripline and the third stripline.

[0072] For example, the three striplines may be implemented by three material layers, with one of the three material layers being embedded between two other of the three material layers.

[0073] 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.

[0074] 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

[0075] 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.

[0076] In embodiments, the flexible substrate comprises polyimide.

[0077] 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.

[0078] In embodiments, the first metallization and the second metallization are connected to one another via a plurality of vias [e.g. electrically].

[0079] 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.

[0080] 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].

[0081] In embodiments, the second center conductor is embedded in the flexible substrate.

[0082] 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 can comprise 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.

[0083] 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].

[0084] 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.

[0085] 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].

[0086] 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].

[0087] In embodiments, the first center conductor and the second center conductor are connected to each other [e.g., electrically] via at least one via.

[0088] 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 disposed between the second metallization and the third metallization, wherein the second center conductor is embedded in the second substrate.

[0089] 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.

[0090] In embodiments, the quantum processor is configured to operate at a cryogenic temperature [e.g., a temperature of less than 1 K].

[0091] 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].

[0092] In embodiments, the flexible waveguide may have a connection pad, wherein the connection pad is arranged in a plane of the first metallization and is isolated from the first metallization [e.g., electrically], wherein the connection pad is connected to the center conductor [e.g., electrically] [e.g., via one or more vias].

[0093] 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.

[0094] 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].

[0095] 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.

[0096] 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.

[0097] 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.

[0098] 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.

[0099] 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.Furthermore, the method 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 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.

[0100] In embodiments, providing the center conductor comprises providing an adhesion layer and / or a diffusion barrier between the first stripline and the second stripline.

[0101] 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].

[0102] 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.

[0103] 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.

[0104] 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.

[0105] In embodiments, the plurality of vias may be arranged such that the plurality of vias surround the center conductor and the pad.

[0106] 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.

[0107] 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.

[0108] Embodiments of the present invention are described in more detail with reference to the accompanying figures. They show: Fig. 1a a schematic sectional view through a flexible waveguide transverse to the wave propagation direction, according to an embodiment, Fig. 1b a schematic sectional view through a flexible waveguide along the wave propagation direction, according to an embodiment, Fig. 2 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, 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, 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, Fig. 4b shows a diagram of the simulated insertion loss in dB of a niobium waveguide plotted against the frequency in GHz, 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, 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, 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, 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 one another 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, Fig. 9 is a flowchart of a method for manufacturing a flexible waveguide according to an embodiment, 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, Fig. 11 is a schematic view of connection surfaces of the flexible waveguide, according to an embodiment, Fig. 12 a schematic block diagram of a quantum computer, according to an embodiment, Fig.13 is a schematic block diagram of a satellite with a flexible waveguide, according to an embodiment, Fig. 14 is a schematic sectional view through a flexible waveguide, a substrate and a detachable connector for connecting the flexible waveguide to the substrate, according to an embodiment, Fig. 15 is a schematic sectional view through a flexible waveguide, a substrate and a detachable connector for connecting the flexible waveguide to the substrate, according to a further embodiment, Fig. 16 shows a diagram comparing crosstalk between two connection surfaces and the corresponding center conductors for two different arrangements of the connection surfaces, Fig.17a is a schematic sectional view through the flexible waveguide, the substrate and the detachable connector for connecting the flexible waveguide to the substrate, wherein the detachable connector comprises a housing and a pressure plate connected to the housing via at least one spring element, according to an embodiment, Fig. 17b is a schematic sectional view through the flexible waveguide, the substrate and the detachable connector for connecting the flexible waveguide to the substrate, wherein the detachable connector comprises a housing and a plurality of pressure plates, each of which is connected to the housing via at least one spring element, according to an embodiment, Fig.17c is a schematic sectional view through the flexible waveguide, the substrate and the detachable connector for connecting the flexible waveguide to the substrate, wherein the detachable connector comprises a housing and an elastic layer connected to the housing, according to an embodiment, Fig. 18 is a schematic sectional view through the flexible waveguide, the substrate and the detachable connector for connecting the flexible waveguide to the substrate, wherein the detachable connector comprises a housing and a spring-loaded stamped and bent part, according to an embodiment, Fig.19 is a schematic sectional view through the flexible waveguide, the substrate and the detachable connector for connecting the flexible waveguide to the substrate, wherein the detachable connector has an alignment element for aligning the detachable connector with respect to the flexible waveguide and / or the substrate, according to an embodiment, Fig. 20 is a schematic plan view of the flexible waveguide, the substrate, and a contact area (or contact zone) between the detachable connector and the flexible waveguide, wherein the flexible waveguide and the substrate have optical markers for aligning the detachable connector with respect to the flexible waveguide and / or the substrate, according to one embodiment, Fig. 21a a schematic sectional view through the flexible waveguide, the substrate and the detachable connector for connecting the flexible waveguide to the substrate of Fig.19, wherein the detachable connector is connected to the mating connector via screw connections, according to an embodiment, Fig. 21b a schematic sectional view through the flexible waveguide, the substrate and the detachable connector for connecting the flexible waveguide to the substrate of Fig. 19, wherein the detachable connector is connected to the mating connector via clamping connections, according to an embodiment, Fig. 22 a schematic view of a layer structure of the connection surfaces of the flexible waveguide, according to an embodiment, and Fig. 23 a schematic block diagram of a quantum computer, according to an embodiment.

[0109] 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.

[0110] Embodiments of the detachable connector described herein enable detachable direct contacting of a flexible waveguide and a rigid substrate, which ensures reliable signal transmission even at very low temperatures (e.g., close to absolute zero in a cryostat).

[0111] However, before embodiments of such a detachable connector are described in Section 2, the underlying flexible waveguide is first described in Section 1. 1. Flexible waveguide

[0112] 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.

[0113] Fig. Figure 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 along 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.

[0114] In embodiments, a first stripline 110_1 of the at least two striplines 110_1, 110_2 may comprise a first superconducting material, wherein a second stripline 110_2 of the at least two striplines 110_1, 110_2 may comprise a second superconducting material, wherein the first superconducting material and the second superconducting material are different.

[0115] 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 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 each other 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.

[0116] 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.

[0117] 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.

[0118] 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. Table 1: Superconducting materials and transition temperature [4] element symbol Transition temperature Solid state normal pressure If the condition specified in brackets is met aluminum Al 1,18 K 3.6K (movie) Americium On 1 K element symbol Transition temperature Solid state normal pressure If the condition specified in brackets is met beryllium Be 0,026 K 9.5K (movie) cadmium CD 0,52 K gallium Ga 1,08 K 8.6K (movie) hafnium Hf 0,38 K mercury Hg 4,15 K Indium In 3,4 K 4.2K (movie) iridium Ir 0,1 K Carbon nanotube 15 K Lanthan La 6 K 12.8 K (20 GPa) lutetium Lu 0,1 K 1.2 K (18 GPa) molybdenum Mon 0,92 K niobium Nb 9,25 K 9.7 K (4.5 GPa) osmium Os 0,7 K Protactinium Pa 1,4 K Lead Pb 7,2 K rhenium re 1,7 K Rhodium Rh 0,000 035 K Ruthenium Ru 0,5 K tin Sn 3,7 K 4.7K (movie) Tantal Ta 4,4 K 4.5 K (40 GPa) Technetium Tc 8,2 K Thorium Th 1,4 K titanium Ti 0,5 K Thallium Tl 2,4 K uranium U 1,3 K 2.2 K (1 GPa) Vanadium V 5,4 K 17.2 K (120 GPa) tungsten W 0,01 K 5.5K (movie) zinc Zn 0,85 K 1.6K (movie) Zirconium Zr 0,6 K 11 K (30 GPa)

[0119] Non-superconducting materials are listed in Table 2 below. Table 2: Non-superconducting materials element symbol Gold Au copper Cu nickel Ni Silver Ag

[0120] In embodiments, the other metallizations (e.g. first metallization, second metallization and / or a plurality of vias (cf. Fig. 3a and Fig. 3b) each have two layers, wherein at least one of the two layers comprises superconducting material.

[0121] In embodiments, the substrate may comprise a polymer, such as polyimide.

[0122] According to exemplary embodiments, 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. In exemplary embodiments, a waveguide, such as a stripline, is realized with at least three metal layers.

[0123] 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.

[0124] 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, they can also be offset from each other to achieve even higher signal integrity; for example, by half a via grid.

[0125] 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.

[0126] Fig.Figure 2 shows a schematic sectional view through a flexible waveguide transverse to the wave propagation direction, according to one embodiment. In other words, Fig. Figure 2 shows a cross-section of a flexible waveguide (e.g. flexible cable) with several indicated lines and three metal layers. As already mentioned with regard to Fig. 1a and Fig. 1b, the waveguide 100 comprises a first metallization 102, a second metallization 104, a flexible substrate 106 disposed between the first metallization 102 and the second metallization 104, and a center conductor 108 embedded in the flexible substrate 106.

[0127] 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.

[0128] As in Fig. As further indicated in Figure 2, the flexible substrate 106 may, in embodiments, 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, for example, be polyimide films.

[0129] As in Fig.As can also be seen in Figure 2, in embodiments, the waveguide 100 may have a plurality of vias 114. The plurality of vias 114 may be arranged between the first metallization 102 and the second metallization 104, or the first metallization 102 and the second metallization 104 may be connected to one another (e.g., electrically) via the plurality of vias 114.

[0130] 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.

[0131] In embodiments, the flexible waveguide 100 may also have further center conductors, which may be arranged in the same substrate 106 between the first and second metallization 102, 104, for example, to the right and / or left with respect to the Fig. 2, or in other words, so that the center conductors are separated from each other by so-called via fences that run between the first and second metallizations 102, 104. In this case, the plurality of vias can serve to reduce crosstalk between the different center conductors. Of course, the flexible waveguide 100 can also have further center conductors arranged in other substrates, e.g., with respect to Fig. 2 above the second metallization 104 and / or below the first metallization 102.

[0132] In other words, Fig.2 shows a cross-section of an exemplary flexible waveguide (e.g., flexible cable). In the flexible waveguide shown (e.g., flexible cable), 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 differently. This 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 µm, film 1 with 25 µm, and a metallization thickness of 0.5 µm. The asymmetric structure achieves the technical advantage that the adaptation of the characteristic impedance at the transition to a connector can be improved.

[0133] Fig. Figure 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 one embodiment. In other words, Fig. Figure 3a shows a cross-section of a flexible waveguide (e.g. flexible cable) with superconducting and normal conducting materials.

[0134] As already mentioned in relation to the Fig. 1a and Fig. As described in Figure 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.

[0135] As 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, which 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, which runs parallel to the first and / or second metallization 102, 104.

[0136] Fig.Figure 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. Figure 3b shows a cross-section of a flexible waveguide (e.g. flexible cable) with superconducting and normal conducting materials - three-part center conductor.

[0137] Compared to the Fig. 3a, the embodiment shown in Fig.3b, the center conductor 108 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 some 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.

[0138] As this is the case in the Fig. 3a and Fig.3b, in embodiments, the other metallizations, ie first metallization 102, second metallization 104 and / or the plurality of vias 114, may also have a plurality of layers, wherein a first layer comprises a superconducting material and a second layer comprises a non-superconducting material.

[0139] 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.

[0140] In other words, Fig. 3a and Fig.3b shows the cross-section of further exemplary flexible waveguides (e.g., flexible cables). The flexible waveguides (e.g., flexible cables) shown are characterized by the metallization of the center conductor and / or the shielding 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.

[0141] 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.

[0142] By combining several conductor materials from normal conductors and superconductors (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. three-digit degrees Celsius). Fig. 3a and Fig.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 is also possible in the combination normal conductor-superconductor-normal conductor or superconductor-normal conductor-superconductor (see Fig. 3b). The magnitude of the simulated S21 parameters (insertion loss) in decibels for one millimeter of cable length is Fig. 4a can be seen.

[0143] In detail, Fig.Figure 4a shows a graph showing the simulated insertion loss in dB of a flexible waveguide with a superconductor and a normal conductor plotted against the 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. Figure 4a shows a diagram of simulated S21 parameters of superconductors and normal conductors at room temperature (50) and cryogenic temperatures (52).

[0144] This shows that the waveguide (e.g., the cable) can be used at both cryogenic and higher temperatures. For comparison, a purely niobium-based flexible waveguide (e.g., flexible cable) is Fig. 4b.

[0145] In detail, Fig.Figure 4b shows a graph showing the simulated insertion loss in dB of a niobium waveguide plotted against 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. Figure 4b shows a diagram of simulated S21 parameters of a niobium waveguide (e.g., niobium cable) at room temperature (60) and cryogenic temperatures (62).

[0146] Fig. Figure 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.Figure 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.

[0147] As 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).

[0148] In other words, Fig. Figure 5 shows the cross-section of another example of a flexible waveguide (e.g., a 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, which can further increase the integration density of the flexible waveguide (e.g., a flexible cable).

[0149] 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 side by side, according to an embodiment.

[0150] 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 an embodiment.

[0151] As already described above in the other embodiments, the Fig. 6a and Fig. 6b, 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 plurality of vias 114 extending between the first metallization 102 and the second metallization 104 and connecting them (e.g. electrically).

[0152] Compared to the embodiments described above, the Fig. 6a and Fig. 6b, the flexible waveguide 100 has not only one center conductor, but two center conductors 108_1 and 108_2.

[0153] In the 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.

[0154] In the 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.

[0155] In other words, Fig. 6a and Fig. 6b shows 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 positioned (directly) one above the other or (directly) next to each other for carrying (e.g., differential) signals. For example, this can achieve higher common-mode rejection and thus better signal integrity.

[0156] The Fig. The center conductors shown in Figures 5a-6b can of course each comprise at least two striplines, wherein at least one of the at least two striplines comprises superconducting material.

[0157] 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.

[0158] Fig. Figure 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 each other via vias 118, according to one embodiment. In other words, Fig. Figure 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 each other by means of a via.

[0159] As already described above, the Fig. The waveguide 100 shown in Figure 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 one another via vias 118.

[0160] 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 plating (i.e., a via) to form a conductor with a larger cross-section. This allows for higher current-carrying capacity and better heat dissipation.

[0161] 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 an embodiment. As shown in Fig. 8, the first stripline 110_1 may be arranged on the second stripline 110_2, wherein the third stripline 110_3 may 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.

[0162] The center conductor 108 is in Fig. 8 is arranged on a first foil 112_1 of a flexible substrate. A second foil could be arranged on the center conductor 108 and the first foil 112_2 to embed the center conductor 108 in the first foil 112_1 and the second foil. The two foils could then again form a flexible substrate, wherein the substrate can be arranged between two metallizations to form a flexible waveguide, as already described in detail above.

[0163] All features of the embodiments disclosed herein described or shown can be combined with one another in any way 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 single-ended or differential signal can generally be transmitted via the flexible waveguide (e.g., flexible cable).

[0164] 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. 1.2. Manufacturing process for a flexible waveguide

[0165] An embodiment of a method for producing a flexible waveguide is described below.

[0166] 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.

[0167] In the following, a further embodiment of a method for producing a flexible waveguide is described. Such a method enables, for example, the automated and reproducible production of flexible waveguides (e.g., flexible cables). The production and automated production 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 described in the Fig. 10a-g is shown.

[0168] Show in detail Fig. 10a-g show schematic cross-sectional views of the flexible waveguide after different steps during its manufacture. In other words, Fig. 10a-g show process steps for producing flexible waveguides.

[0169] In detail, Fig. 10a is 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.

[0170] 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.

[0171] 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.

[0172] In embodiments, in step of Fig. 10b a metal layer on both sides as well as in the borehole walls of the foil from the step of Fig. 10a, for example, by sputtering. It may be necessary to activate the surface of the substrate foil beforehand (within the sputtering tool, without interrupting the vacuum). This ensures the required adhesion of the metal to the foil. Another way to improve the adhesion between a metal layer, such as niobium, and a PI foil is 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.

[0173] 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.

[0174] 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) 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 (e.g., electrically) via the at least one via.

[0175] 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).

[0176] 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.

[0177] In embodiments, the metallized film can now be laminated with a second dielectric layer, with or without an (acrylic) adhesive between the two film layers.

[0178] Fig. 10e shows a schematic 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.

[0179] 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.

[0180] 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.

[0181] 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.

[0182] 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.

[0183] In some embodiments, a photoresist can be applied to the layer composite and exposed to light to pattern the shield layer metallization. Niobium can be patterned, for example, by plasma etching. When using other metallizations, 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.

[0184] Through the structuring in the Fig. 10g are finally the steps shown in the step from Fig. 10c are electrically separated from the surrounding shielding layers. This results in a contact surface according to Fig. 11. 1.3. Connection surfaces of the flexible waveguide

[0185] Fig. Figure 11 shows a schematic view of connection pads 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.

[0186] As in Fig. As can be seen in Figure 11, the connection pads 130_1-130_3 may be exposed in a plane of the first metallization 102 (or alternatively, the second metallization), i.e., electrically insulated from the first metallization 102. The connection pads 130_1-130_3 may be connected to respective center conductors of the flexible waveguide 100 via respective vias 132_1-132_3.

[0187] 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.

[0188] In embodiments, the three connection surfaces 130_1-130_3 may have different distances from an end 134 of the flexible waveguide. 1.4. Applications of the flexible waveguide

[0189] 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. 1.4.1 Quantum computing with superconducting qubits

[0190] One conceivable application of the flexible waveguide (e.g., interconnection system) is signal transmission in a quantum computer. Embodiments of the flexible waveguide can be used to replace coaxial cables. This can significantly increase the signal density in the cryostat. By using superconducting materials for the signal line 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.

[0191] Fig. Figure 12 shows a schematic block diagram of a quantum computer 300 according to one embodiment. In other words, Fig. Figure 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 analyzer 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 analyzer 304.

[0192] As 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.

[0193] 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.

[0194] The shielding concept also ensures low crosstalk between the cables and thus high signal integrity. Manufacturing can be carried out using the process described above. 1.4.2 Phased array antennas

[0195] 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 allows for a more compact antenna with few or no active components. Active signal processing takes place in a central unit.

[0196] 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.

[0197] Fig. Figure 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. 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.

[0198] Remote antennas connected by highly integrated cables are also conceivable for radar devices with electronically controlled group antennas. 1.4.3 Sensor signal connection for automotive applications

[0199] 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.

[0200] 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. 2. Integration of RF components into a flexible waveguide

[0201] Fig. 14 shows a schematic sectional view through a flexible waveguide 100, a substrate 150, and a detachable connector 160 for connecting the flexible waveguide 100 to the substrate 150, according to an embodiment. In Fig. 14, the cut surface shown runs in the longitudinal direction of the flexible waveguide.

[0202] The detachable connector 160 is designed to be applied to the flexible waveguide (e.g., mechanically) and to be connected to a mating connector 180 that bears against the substrate 150 (e.g., mechanically), wherein the detachable connector 160 is designed to exert a compressive force 162 on at least one connection surface 130 of the flexible waveguide when connecting the detachable connector 160 to the mating connector 180 or in a state connected to the mating connector 180 (e.g., when the detachable connector 160 is connected to the mating connector 180), in order to press the at least one connection surface 130 onto at least one mating connection surface 154 of the substrate.

[0203] As in Fig. 14 is indicated by way of example, a counter-pressure force 152 can be exerted on the at least one mating connection surface 154 of the substrate by the connection between the detachable connector 160 and the mating connector 180, wherein the counter-pressure force 152 opposes the pressure force 162, so that the at least one connection surface 130 of the flexible waveguide 100 and the at least one mating connection surface 154 of the substrate 150 are pressed / pressed against one another.

[0204] In embodiments, the compressive force 162 may act perpendicularly to the at least one connection surface 130. In other words, in embodiments, the compressive force 162 may act transversely to a longitudinal axis of the flexible waveguide 100.

[0205] In embodiments, the counterpressure force 152 can act perpendicularly on the at least one counter connection surface 154.

[0206] In embodiments, the detachable connector 160 may be configured to engage a first side 166 of the flexible waveguide 100 that is opposite a second side 168 of the flexible waveguide 100 that includes the at least one (e.g., electrical) connection surface 130 of the flexible waveguide 100.

[0207] Accordingly, the mating connector 180 may abut the substrate 150 on a first side 156 opposite a second side 158 of the substrate 180 having the at least one mating connection surface 154.

[0208] In embodiments, the flexible waveguide 100 may be configured as a ribbon cable.

[0209] In embodiments, the substrate 150 may be a rigid substrate, such as a printed circuit board.

[0210] In order to enable a good RF connection between the flexible waveguide 100 and the rigid substrate, in embodiments, connection surfaces 130, 154 are provided on the second side (e.g., outer side) 168 of the waveguide 100 and also on the second side (e.g., outer side) 158 of the substrate 150, which are pressed together using a mechanical structure (= detachable connector 160 (and mating connector 180)). In embodiments, these are each located on one side in a recess on an outer layer 166, 156, are designed to be as low-reflection as possible, and are identical on the substrate 150 and the flexible waveguide 100, except for the respective conductor width. In embodiments, the connection surfaces (e.g., contact surfaces) 130, 154 can be longer or larger than electrically necessary, e.g., to counteract manufacturing and alignment tolerances.

[0211] Fig. 15 shows a schematic sectional view through the flexible waveguide 100, a substrate 150, and a detachable connector 160 for connecting the flexible waveguide 100 to the substrate 150, according to another embodiment. Fig. 15, the section shown runs in the longitudinal direction of the flexible waveguide 100. In other words, Fig. 15 shows a cross section of the high frequency connector.

[0212] Compared to the Fig. 14 are shown in the embodiment shown in Fig. The internal structure of the flexible waveguide 100 and the substrate 150 is shown in the embodiment shown in Fig. 15.

[0213] As in Fig. As can be seen in Figure 15, the flexible waveguide 100 may include a first metallization 102, a second metallization 104, and a flexible substrate 106, wherein the flexible substrate 106 is disposed between the first metallization 102 and the second metallization 104. Here, the first side 166 of the flexible waveguide may include the second metallization 104, while the second side 168 of the flexible waveguide 100 may include the first metallization 102.

[0214] Furthermore, the flexible waveguide 100 can have at least one center conductor 108, which is embedded in the flexible substrate 106 and which is connected to the at least one connection surface 130 via at least one via 132. The at least one connection surface 130 can be exposed on the second side 168 of the flexible waveguide 100, i.e., can be electrically insulated from the first metallization 102, e.g., by a distance between the first metallization 102 and the at least one connection surface 130.

[0215] In embodiments, the flexible waveguide 100 can be the flexible waveguide described in section 1. For example, the at least one center conductor can comprise at least two striplines, wherein at least one of the at least two striplines comprises a superconducting material, and / or the center conductor 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 at least one center conductor to comprise only one stripline made of superconducting or non-superconducting material and / or for the at least one center conductor to be arranged symmetrically (i.e., centrally) with respect to the first metallization 102 and the second metallization 104.

[0216] In embodiments, the substrate 150 can have a first metallization 152 and a second metallization 154. In this case, the first side 156 of the substrate 150 can have the second metallization 154, while the second side 158 of the substrate 150 can have the first metallization 152. Furthermore, at least one center conductor 158 can be embedded in the substrate 150, wherein the at least one center conductor 157 is connected to the at least one mating connection surface 154 via at least one via 151. The at least one mating connection surface 154 can in this case be exposed on the second side 158 of the substrate 150, i.e., be electrically insulated from the first metallization 152, e.g., by a distance between the first metallization 152 and the at least one mating connection surface 154.

[0217] In exemplary embodiments, the connection pads 130, 154 can be connected to the signal lines 108, 157 via vias (signal vias) 132, 151. The signal vias 130, 154 thus guide the respective inner conductor 108, 157 to an outer layer. The electrical signal guided to the outer layer is now located on the same plane on both the substrate (e.g., printed circuit board, PCB) and the flexible waveguide. Thus, the electrical signal chain runs as follows: inner conductor (flexible waveguide) - via (flexible waveguide) - connection pad (flexible waveguide) - connection pad (substrate) - via (substrate) - inner conductor (substrate).

[0218] When using reciprocal materials (such as copper, aluminum, polyimide, niobium), the signal chain is bidirectional and symmetrical in its transmission behavior. Single or multiple vias can be used to connect the signal line to the connection pad.

[0219] In some embodiments, the dielectrics of the waveguides in the area of ​​the RF connector can be designed with different thicknesses, i.e., asymmetrically, to ensure a low-reflection transition. In some embodiments, the dimensions of the connection surfaces can be optimized for low reflections.

[0220] In order to minimize crosstalk between two waveguides in the area of ​​the connector, in embodiments the connection surfaces 130 can be surrounded by shielding vias 114 and a ground plane, as shown in Fig. 11. The shielding vias 114 can be arranged in a single row or, to achieve even lower crosstalk, in multiple rows. In addition, the connection areas (see Fig. 11) can be arranged offset, as this can reduce (or even minimize) crosstalk between the individual lines. For example, the recesses for the connection pads 130 can have dimensions of 1.36 mm x 0.55 mm, and the connection pads 1 mm x 0.1 mm.

[0221] Fig. Figure 16 shows a diagram comparing crosstalk between two pads and their corresponding center conductors for two different pad arrangements. Fig. In Figure 16, the ordinate represents the crosstalk in dB, and the abscissa represents the frequency in GHz. A first curve 250 describes the case where the two connection surfaces are at the same distance from one end of the flexible waveguide, while a second curve 252 describes the case where the distances between the two connection surfaces and one end of the flexible waveguide differ by 2 mm (cf. Fig. 11).

[0222] In embodiments, a space-optimized contact between the flexible waveguide 100 and the rigid substrate 150 is achieved by directly pressing the contact surfaces 130, 154 of both contact partners together.

[0223] Embodiments make it possible to generate a specific force homogeneously across the entire contact area of ​​the connecting partners to be contacted. The force can be selected such that a reduced (or even minimal) contact resistance is achieved without damaging the contact surfaces of the connecting partners. Embodiments provide two housed connector halves (= detachable connector 160 and mating connector 180), into which the rigid substrate 150 and the flexible waveguide 100 are inserted and fixed, respectively.

[0224] Fig. 17a shows a schematic sectional view through the flexible waveguide 100, the substrate 150 and the detachable connector 160 for connecting the flexible waveguide 100 to the substrate 150. In Fig. 17a, the cutting axis runs transversely to the longitudinal axis of the flexible waveguide 100.

[0225] As in Fig. 17a, the detachable connector 160 can have a housing 170 and a pressure plate 172, which is connected to the housing via at least one spring element 174, wherein the detachable connector 160 is designed to be applied to the flexible waveguide 100 via the pressure plate 172. When the detachable connector 160 is connected to the mating connector 180 or in the state connected to the mating connector 180, the at least one spring 170 is tensioned in order to exert a compressive force on the at least one connection surface 130 of the flexible waveguide 100, so that the at least one connection surface 130 of the flexible waveguide 100 and the at least one mating connection surface 154 of the substrate 150 are pressed against one another.

[0226] In the Fig. In the embodiment shown in Fig. 17a, it is assumed by way of example that the detachable connector 160 has exactly one pressure plate 172, which is connected to the housing via a plurality of spring elements 174.

[0227] Fig. 17b shows a schematic sectional view through the flexible waveguide 100, the substrate 150 and the detachable connector 160 for connecting the flexible waveguide 100 to the substrate 150. In Fig. 17b, the cutting axis runs transversely to the longitudinal axis of the flexible waveguide 100.

[0228] Compared with the Fig. 17a is shown in the embodiment shown in Fig. 17b, it is assumed that the detachable connector 160 has a plurality of pressure plates 172, wherein each of the plurality of pressure plates 172 is connected to the housing 170 via at least one spring element 174.

[0229] Fig. 17c shows a schematic sectional view through the flexible waveguide 100, the substrate 150 and the detachable connector 160 for connecting the flexible waveguide 100 to the substrate 150. In Fig. 17c, the cutting axis runs transverse to the longitudinal axis of the flexible waveguide 100.

[0230] As in Fig. 17c, the detachable connector 160 can have a housing 170 and an elastic layer 176, wherein the elastic layer 176 is connected to the housing 170, wherein the detachable connector 160 is configured to be applied to the flexible waveguide 100 via the elastic layer 176. When connecting the detachable connector 160 to the mating connector 180 or in the state connected to the mating connector 180, the elastic layer 176 is compressed in order to exert the compressive force on the at least one connection surface 130 of the flexible waveguide 100, so that the at least one connection surface 130 of the flexible waveguide 100 and the at least one mating connection surface 154 of the substrate 150 are pressed against one another.

[0231] In other words, Fig. 17a-c show schematic sectional views through the flexible waveguide 100, the substrate 150 and the detachable connector 160, wherein spring-loaded elements in the contact area distribute the force homogeneously over the contact area and maintain the force even after cooling from room temperature to a few Kelvin: a) a spring-loaded pressure plate for the entire contact area of ​​the connection partners, b) spring-loaded pressure plate for each contact pad, c) flexible intermediate layer.

[0232] For homogeneous force introduction, spring-loaded pressure plates 172 can be introduced into the housing 170 in exemplary embodiments in such a way that the force acts perpendicularly on the contact surfaces 130, 154 of the connection partners (see Fig. 17a and Fig. 17b). Possible springs include compression springs, disc springs, wave springs, or straight flat springs. Preloading the springs allows for a precise force to be set. A key advantage of the spring elements is that they can compensate for any unevenness or roughness in the contact area of ​​the connecting elements. Furthermore, a uniform force can be ensured even over a wide contact area. Another key advantage of the solution is that thermal expansion / shrinkage of the connecting elements can be compensated, making this contact particularly suitable for cryogenic applications.

[0233] Alternatively, in embodiments, materials can be applied to the housing that have a high elasticity even at low temperatures (10 mK) (see Fig. 17c). Such materials include indium or photoresists (SU8). Due to their elasticity, these could transfer the force in the contact area homogeneously from the housing to the contact partners.

[0234] Fig. 18 shows a schematic sectional view through the flexible waveguide 100, the substrate 150 and the detachable connector 160 for connecting the flexible waveguide 100 to the substrate 150. In Fig. 18, the cutting axis runs transversely to the longitudinal axis of the flexible waveguide 100.

[0235] As in Fig. 18, the detachable connector 160 can have a housing 170 and a spring-loaded stamped and bent part 175, wherein the spring-loaded stamped and bent part 175 is connected to the housing 170, wherein the detachable connector 160 is designed to be applied to the flexible waveguide 100 via the spring-loaded stamped and bent part 175. When the detachable connector 160 is connected to the mating connector 180 or in the state connected to the mating connector 180, the spring-loaded stamped and bent part 175 is tensioned in order to exert a compressive force on the at least one connection surface 130 of the flexible waveguide 100, so that the at least one connection surface 130 of the flexible waveguide 100 and the at least one mating connection surface 154 of the substrate 150 are pressed against one another.

[0236] In embodiments, an alignment of the contact partners can be achieved by mechanical alignment elements according to Fig. 19. These serve as rigid mechanical stops when connecting the two connector parts. These can, for example, be designed positioning ribs that are inserted into a tightly toleranced cavity.

[0237] In detail, Fig. 19 is a schematic sectional view through the flexible waveguide 100, the substrate 150, and the detachable connector 160 for connecting the flexible waveguide 100 to the substrate 150, wherein the detachable connector has an alignment element 180 for aligning the detachable connector with respect to the flexible waveguide 100 and / or the substrate 150, according to one embodiment. Fig. 19, the cutting axis runs transversely to the longitudinal axis of the flexible waveguide 100.

[0238] As in Fig. 19, the detachable connector 160 may include at least one mechanical protruding alignment element 180, wherein the mechanical alignment element 180 is configured to effect alignment between the detachable connector 160, the flexible waveguide 100, and the substrate 150 upon application of the detachable connector 160 to the flexible waveguide 100 by connecting the mechanical alignment element 180 to a mating alignment element 182 of the flexible waveguide 100 and a mating alignment element 184 of the substrate 150.

[0239] In embodiments, the mechanical alignment element 180 may be a pin or ridge, wherein the alignment counter element 182 of the waveguide may be a cavity corresponding to the pin or ridge (e.g., a hole), and wherein the alignment counter element 184 of the substrate 150 may be a cavity corresponding to the pin or ridge (e.g., a hole).

[0240] Of course, the flexible waveguide 100 can also have a pin or ridge, with the detachable connector 160 and / or the substrate 150 having corresponding cavities. Alternatively, the substrate 150 can also have a pin or ridge, with the detachable connector 160 and / or the flexible waveguide 100 having corresponding cavities.

[0241] In Fig. 19, it is assumed by way of example that the detachable connector 160, the housing 170 and the pressure plate 172, which is connected via at least one spring element 174, from the in Fig. 17a. Alternatively, however, the embodiments according to Fig. 17b, Fig. 17c or Fig. 18 apply.

[0242] In other words, Fig. Figure 19 shows a spring-loaded pressure plate for homogeneous pressure distribution in the contact area. Through the simultaneous alignment of both contact partners (rigid substrate 105 and flexible waveguide 100) via the mechanical alignment elements near the contact zone, a small alignment tolerance between the contact surfaces of the contact partners can be achieved. For optical control of the alignment, additional optical position marks can be provided next to the contact zone, as shown below using Fig. 20 is explained in more detail.

[0243] Fig. Figure 20 shows a schematic top view of the flexible waveguide 100, the substrate 150, and a contact area (or contact zone) 190 between the detachable connector 160 and the flexible waveguide, wherein the flexible waveguide 100 and the substrate 150 have optical markers 192, 194 for aligning the detachable connector with respect to the flexible waveguide 100 and / or the substrate 150, according to one embodiment. In other words, Fig. 20 shows optical position marks 192, 194 for aligning the two contact partners to each other (top view).

[0244] In detail, the detachable connector may have at least one opening (not shown in Fig. 20), which is arranged such that when the detachable connector 160 is applied to the flexible waveguide 100 and connected to the mating connector 180, a first optical marking 192 (e.g., crosshairs, line) of the flexible waveguide 100 and (e.g., simultaneously) a second optical marking 194 (e.g., crosshairs, line) of the substrate 150 are visible through the opening as soon as the detachable connector 160, the waveguide 100, and the substrate 150 are correctly aligned with one another. For this purpose, the flexible waveguide 100 can also have an opening 196, so that the second optical marking 194 of the substrate 150 is visible.

[0245] In embodiments, by combining both functions (spring-loaded contact force introduction and low-tolerance mechanical and optical alignment), a contact between rigid and flexible substrates (ie flexible waveguide 100 and substrate 150) can be created, in which a very high density of signal lines in the contact zone and reliable signal transmission can be achieved even at very low temperatures (10 mK).

[0246] The respective housings of the contact partners can be used in embodiments according to Fig. 21a are finally connected by means of detachable connecting elements (e.g. screws) so that the alignment of the rigid substrate 150 to the flexible waveguide 100 can be permanently ensured.

[0247] In detail, Fig. 21a is a schematic sectional view through the flexible waveguide 100, the substrate 150 and the detachable connector 160 for connecting the flexible waveguide 100 to the substrate 150 of Fig. 19, wherein the detachable connector 160 is connected to the mating connector 180 via screw connections 198. In other words, Fig. 21a shows the screwing of the housings for mounting the connection system.

[0248] In cryogenic applications, in addition to the detachable connection by screws, it is also possible to connect the housing parts by means of clamping elements, as is the case in Fig. 21b is shown.

[0249] In detail, Fig. 21b is a schematic sectional view through the flexible waveguide 100, the substrate 150 and the detachable connector 160 for connecting the flexible waveguide 100 to the substrate 150 of Fig. 19, wherein the detachable connector 160 is connected to the mating connector 180 via detachable clamping elements 199. In other words, Fig. 21b shows a detachable connection of the connecting partners by clamping elements, which lead to a pressing of the housing halves upon cooling.

[0250] In some embodiments, the clamping elements 199 may comprise (or be made of) a material that contracts more at low temperatures than the materials of the housing. For example, if the housing is made of copper, clamping elements made of brass may be used.

[0251] In further embodiments (not shown), the detachable connector 160 can be connected to the mating connector 180 via a clamping lever. For example, a rotational axis of the clamping lever can be arranged on the mating connector 180, whereby a movement of the clamping lever can exert a clamping force on the detachable connector 160 and the mating connector 180. In particular, a guide or involute can be provided to achieve a defined increase in the clamping force.

[0252] In embodiments, the connection created in this way is detachable and scalable.

[0253] Further embodiments are described in more detail below. 2.1 Use of shielding vias

[0254] Some designs achieve high shielding attenuation between parallel waveguides. Such designs are suitable for applications where values ​​better than -60 dB are desired.

[0255] According to some embodiments, shielding vias can be used for this purpose (see e.g. Fig. 11). For example, the connection surfaces 130 can be surrounded by shielding vias and arranged offset to enable high shielding attenuation. 2.2 Asymmetric structure

[0256] Some embodiments provide a detachable connector (e.g. plug) that ensures low-reflection signal transmission.

[0257] According to some embodiments, the dielectrics of the waveguides in the area of ​​the RF connector can be arranged asymmetrically to ensure low-reflection signal transmission. Furthermore, the geometry of the connection surfaces and the ground plane can be optimized for low reflections. 2.3 Geometric structure of the flexible waveguide

[0258] Some embodiments enable high signal density even in applications that target more than 50 signal lines per inch.

[0259] According to some embodiments, the use of flexible substrates for the production of flexible waveguides allows for the use of manufacturing processes (e.g., sputtering) that can achieve a high density of shielded signal lines. By directly contacting the contact zones of the rigid substrate and the flexible waveguide, numerous signal lines can be connected in a space-saving manner. 2.4 Homogeneous force distribution in the contact area

[0260] Some embodiments create a detachable connector (e.g., a connector) that generates a homogeneous force distribution in the contact area. The force has a significant influence on the contact resistance, which tends to decrease with increasing force.

[0261] According to some embodiments, a spring-loaded pressure plate can ensure a homogeneous force distribution across the entire contact area between two contact partners (rigid substrate and flexible waveguide). This is achieved by introducing the contact force directly into the contact area through spring elements. This is particularly advantageous for cryogenic applications, as the spring elements can compensate for thermal expansion or shrinkage of all contact partners. The force can be optimally adjusted by preloading the springs. 2.5 Choice of contact force and contact material

[0262] Some embodiments create a connection with the lowest possible contact resistance. The contact resistance is composed of the constriction resistance (restriction of current flow by asperites) and the foreign layer resistance (e.g., oxide layers).

[0263] Contact force: The force acting on the contact point generally has a positive effect on the contact resistance. A higher force leads to an improved mechanical connection between the surfaces and breaks down oxide and dirt layers. Therefore, according to some embodiments, the highest possible contact force should be selected, while still avoiding plastic deformation of the contact pads on both contact partners. This is achieved by elastic spring elements in the contact area. These can be preloaded to generate an optimal contact force for the connection.

[0264] Material: The hardness of the material in the contact area is a key parameter for contact resistance, as it directly influences how well the surfaces of two materials adapt to each other during contact. If a material is soft, it can adapt to uneven surfaces. Therefore, according to some embodiments, a contact material should be selected that exhibits low hardness in the case of cryogenic applications, i.e., even at very low temperatures (approx. 10 mK). Such a material is, for example, indium or gold, which is applied to the contact surfaces of the contact partners.

[0265] Oxide layers: Oxide and dirt layers significantly influence contact resistance due to their low conductivity. These can be broken down by applying sufficient contact force in the contact area. In some embodiments, the formation of an oxide layer can be prevented by additionally applying a layer to the contact surfaces that is less prone to oxidation. Examples of such materials include precious metals such as gold or silver.

[0266] The features described in this section 2.5 result in an exemplary layer structure according to Fig. 22.

[0267] In detail, Fig. 22 shows a schematic view of a layer structure of the connection surfaces 130 of the flexible waveguide 100, according to an embodiment. In other words, Fig. 22 shows a possible layer structure of the contact pads 130 of the flexible waveguide 100.

[0268] As in Fig. 22, the pads 130 may each include: (1) a niobium layer 136 (e.g., disposed on the second side 168 of the flexible waveguide 100), (2) an indium layer 137 disposed on the niobium layer 136, and (3) a silver or gold layer 138 disposed on the indium layer 137. 2.6 Easy detachability of the connection

[0269] Some embodiments provide a simple, repairable and / or space-optimized attachment of the cable and connectors.

[0270] In some embodiments, the use of flexible waveguides allows the cable harness to be ideally adapted to the available limited space (e.g., in a cryostat). A detachable connection between two contact partners facilitates contacting the contact partners and allows for the replacement of cables as needed. 2.7 Low heat transfer

[0271] Some embodiments provide low heat transfer through the lines, which is advantageous for cryostat applications, for example.

[0272] According to some embodiments, the small cross-section of the flexible waveguide (< 100 µm) can significantly reduce passive heat transfer compared to conventional cables. Furthermore, the substrate and the flexible waveguide are in contact with materials with good thermal conductivity, such as oxygen-free copper. This allows heat to be dissipated from the substrate and waveguide by thermal conduction. By also making the pressure plate in the contact area from a thermally conductive material (e.g., Cu, Cu-OF), the heat resulting from heat losses due to contact resistance can be dissipated. 2.8. Application examples

[0273] Examples of such applications can be used when signals need to be transmitted in a very tight space with high signal integrity. The connector's spring-loaded pressure elements ensure optimal force transmission in the contact zone in any installation position. Two exemplary application areas are briefly explained below. 2.8.1 Quantum computers

[0274] Embodiments can be used for signal transmission in a quantum computer, e.g. as described in Fig. 23 is shown.

[0275] Fig. Figure 23 shows a schematic block diagram of a quantum computer 300 according to one embodiment. 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.

[0276] In other words, Fig. Figure 23 shows an application of the cables in the cryostat from room temperature to 20 mK and, in the enlarged area, a contacting of the flexible waveguide 100 with the substrate via the detachable connector.

[0277] Embodiments of the detachable connector can be used to replace the conventionally used large plug connections. Together with the waveguide described herein, both the sometimes large plug connections (e.g., SMA connectors) and the coaxial cables can be substituted. This can significantly increase the signal density in the cryostat. According to some embodiments, heat losses can be reduced by using superconducting materials for the signal line and shielding layers of the flexible waveguide (e.g., niobium). This also makes it possible to increase the number of lines in the cryostat. Thus, embodiments can enable signal and power supply in the cryostat even with an increasing number of qubits in the quantum computer. 2.8.2 Vehicle wiring harness

[0278] Examples of such implementations 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. Another key advantage of this solution is that the flexible waveguide can be adapted to the vehicle's contours, thus ensuring optimal use of the installation space. This is particularly important given the increasing functional density of modern vehicles. 3. Further examples

[0279] Embodiments described herein provide a radio frequency connector for connecting a flexible (e.g., multi-core) waveguide and a rigid substrate.

[0280] Embodiments create a flexible (e.g. multi-core) waveguide with corresponding contact pads for the high-frequency connector.

[0281] Embodiments provide a quantum computer with such a flexible waveguide with contact pads.

[0282] Embodiments of the detachable connector allow alignment of the flexible waveguide to the substrate.

[0283] Examples of embodiments can be used in the cryogenic temperature range.

[0284] 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.

[0285] 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. Bibliography [1] Krinner, S., Storz, S., Kurpiers, P. et al. “Engineering cryogenic setups for 100-qubit scale superconducting circuit systems” - EPJ Quantum Technology 6(1) [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. [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) [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.wikipedia.org / w / index.php?title=Liste_der_Sprungtemperaturen_che mischer_Elemente&oldid=224223235 (Accessed: September 22, 2023, 12:39 UTC) [5] Bhargav Yelamanchili, Archit Shah, Sherman E. Peek et al. “Face-to-Face Cable Interconnect Scheme for Thin Flexible Superconducting Stripline Cables” - IEEE Transactions on Applied Superconductivity (Volume: 32, Issue: 4, June 2022) QUOTES CONTAINED IN THE DESCRIPTION

[0000] This list of documents submitted by the applicant was generated automatically and is included solely for the convenience of the reader. This list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions. Cited non-patent literature

[0000] 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

[0285] Shuna Wang, Wenbing Jiang, Huiqin Yu et al. “Functional flexible cables for cryogenic quantum systems” - 2022

[0285] "List of transition temperatures of chemical elements." In: Wikipedia - The Free Encyclopedia. Edited on: July 4, 2022, 10:16 UTC. URL: https: / / de.wikipedia.org / w / index.php?title=Liste_der_Sprungtemperaturen_che mischer_Elemente&oldid=224223235 (Accessed: September 22, 2023, 12:39 UTC

[0285] Bhargav Yelamanchili, Archit Shah, Sherman E. Peek et al. „Face-to-Face Cable Interconnect Scheme for Thin Flexible Superconducting Stripline Cables“ - IEEE Transactions on Applied Superconductivity (Volume: 32, Issue: 4, June 2022

[0285]

Claims

[1] Detachable connector (160) for connecting a flexible waveguide (100) to a substrate (150), wherein the detachable connector (160) is designed to be applied to the flexible waveguide (100) and to be connected to a mating connector (180) which is applied to the substrate (150), wherein the detachable connector (160) is designed to exert a compressive force (162) on at least one connection surface (130) of the flexible waveguide (100) when connecting the detachable connector to the mating connector (180) or in a state connected to the mating connector (180) in order to press the at least one connection surface (130) onto a mating connection surface (154) of the substrate. [2] Detachable connector (160) according to the preceding claim, wherein the compressive force (162) acts perpendicularly on the at least one connection surface (130). [3] A detachable connector (160) according to any one of the preceding claims, wherein the compressive force (162) acts transversely to a longitudinal axis of the flexible waveguide (100). [4] Detachable connector (160) according to one of the preceding claims, wherein the detachable connector (160) is configured to be applied to a first side (166) of the flexible waveguide (100) which is opposite a second side (168) of the flexible waveguide (100) which has the at least one connection surface (130) of the flexible waveguide (100). [5] Detachable connector (160) according to one of the preceding claims, wherein the mating connector (180) abuts the substrate (150) on a first side (156) opposite a second side (158) of the substrate (150) having the at least one mating connection surface (154). [6] Detachable connector (160) according to one of claims 1 to 5, wherein the detachable connector (160) comprises: a housing (170), and at least one pressure plate (172) which is connected to the housing (170) via at least one spring element (174), wherein the detachable connector (160) is designed to be applied to the flexible waveguide (100) via the pressure plate (172). [7] Detachable connector (160) according to claim 6, wherein when connecting the detachable connector (160) to the mating connector (180) or in the state connected to the mating connector (180), the at least one spring (174) is tensioned to exert the compressive force (162) on the at least one connection surface (130) of the flexible waveguide (100). [8] Detachable connector (160) according to one of claims 6 to 7, wherein the at least one printing plate (172) is exactly one printing plate, wherein the pressure plate is connected to the housing (170) via exactly one spring element (174) or via a plurality of spring elements. [9] Detachable connector (160) according to one of claims 6 to 7, wherein the at least one printing plate (172) is a plurality of printing plates, wherein each of the plurality of pressure plates is connected to the housing (170) via at least one spring element (174). [10] Detachable connector (160) according to one of claims 6 to 9, wherein the at least one spring element (174) is a compression spring, a disc spring, a wave spring, a straight flat spring or a stamped and bent part. [11] Detachable connector (160) according to one of claims 1 to 5, wherein the detachable connector (160) comprises: a housing (170), and an elastic layer (176) connected to the housing (170), wherein the detachable connector (160) is configured to be applied to the flexible waveguide (100) via the elastic layer (176). [12] Detachable connector (160) according to claim 11, wherein when connecting the detachable connector (160) to the mating connector (180) or in the state connected to the mating connector (180), the elastic layer (176) is compressed in order to exert the compressive force on the at least one connection surface (130) of the flexible waveguide (100). [13] The detachable connector (160) of any one of claims 11 to 12, wherein the elastic layer (176) is elastic at cryogenic temperatures. [14] A detachable connector (160) according to any one of claims 11 to 13, wherein the elastic layer (176) comprises indium or a photoresist. [15] Detachable connector (160) according to one of the preceding claims, wherein the detachable connector (160) is designed to be connected to the mating connector (180) via a detachable connection. [16] A detachable connector (160) according to claim 15, wherein the detachable connection is a screw connection (198). [17] A detachable connector (160) according to claim 15, wherein the detachable connection is a clamping connection (199). [18] A releasable connector according to claim 17, wherein a material of the clamping elements of the clamping connection (199) has a higher coefficient of thermal expansion than a material of the housing (170). [19] Detachable connector (160) according to one of the preceding claims, wherein the detachable connector (160) has at least one mechanical alignment element, wherein the mechanical alignment element (182) is configured to effect alignment between the detachable connector (160), the flexible waveguide (100), and the substrate (150) upon application of the detachable connector (160) to the flexible waveguide (100) by connecting the mechanical alignment element (182) to a mating alignment element (184) of the flexible waveguide (100) and a mechanical alignment element (184) of the substrate (150). [20] A detachable connector according to the preceding claim, wherein the mechanical alignment element (180) is a pin and wherein the alignment counter element (182) is a cavity corresponding to the pin, or wherein the mechanical alignment element (180) is a cavity and wherein the alignment counter element (182) is a pin corresponding to the cavity. [21] Detachable connector (160) according to one of claims 1 to 20, wherein the detachable connector (160) has at least one opening, wherein the opening is arranged such that when the detachable connector (160) is applied to the flexible waveguide (100) and the detachable connector (160) is connected to the mating connector (180), a first optical marking (192) of the flexible waveguide (100) and a second optical marking (194) of the substrate (150) are visible through the opening as soon as the detachable connector (160), the waveguide and the substrate (150) are correctly aligned with one another. [22] Detachable connector (160) according to one of claims 1 to 20, wherein the detachable connector (160) has at least a first optical marking, wherein the first optical mark is arranged such that when the detachable connector is applied to the flexible waveguide (100) and the detachable connector is connected to the mating connector (180), the first optical mark is arranged in line with a second optical mark (192) of the flexible waveguide (100) and a third optical mark (194) of the substrate (150) as soon as the detachable connector (160), the waveguide and the substrate (150) are correctly aligned with one another. [23] Detachable connection system, with the following features: a detachable connector (160) according to one of claims 1 to 22, and a mating connector (180) configured to be applied to the substrate (150). [24] Flexible waveguide (100), having the following features: a first metallization (102), a second metallization (104), a flexible substrate (106) arranged between the first metallization (102) and the second metallization (104), at least one center conductor (108) embedded in the flexible substrate (106), and at least one connection surface (130) which is arranged and exposed in a plane of the first metallization (102) or the second metallization (104), wherein the at least one connection surface (130) is connected to the at least one center conductor (108). [25] Flexible waveguide (100) according to claim 24, wherein the at least one connection surface (130) is insulated from the first metallization (102). [26] Flexible waveguide (100) according to one of claims 24 to 25, wherein the at least one center conductor (108) is connected to the at least one connection surface (130) via at least one via (132). [27] Flexible waveguide (100) according to one of claims 24 to 26, wherein the flexible waveguide (100) has a plurality of vias connecting the first metallization (102) and the second metallization (104), wherein the plurality of vias surround the at least one center conductor (108) and the at least one connection surface (130). [28] Flexible waveguide (100) according to one of claims 24 to 27, wherein the at least one center conductor (108) comprises a first center conductor (108_1) and a second center conductor (108_2), wherein the at least one connection surface (130) has a first connection surface (130_1) and a second connection surface (130_2), wherein the first connection surface (130_1) and the second connection surface (130_2) are arranged in a plane of the first metallization (102) and are insulated from the first metallization (102), wherein the first connection surface (130_1) is connected to the first center conductor (108_1) and the second connection surface (130_2) is connected to the second center conductor (108_2). [29] Flexible waveguide (100) according to claim 28, wherein the flexible waveguide (100) has a plurality of vias, wherein the plurality of vias are arranged such that the plurality of vias surround the first center conductor (108_1) and the first pad (130_1), surround the second center conductor (108_2) and the second pad (130_2), and shield the first center conductor (108_1) and the first pad (130_1) from the second center conductor (108_2) and the second pad (130_2). [30] Flexible waveguide (100) according to one of claims 28 to 29, wherein the first terminal surface (130_1) and the second terminal surface (130_2) are arranged adjacent to one end of the flexible waveguide (100). [31] Flexible waveguide (100) according to claim 30, wherein the first connection surface (130_1) and the second connection surface (130_2) have different distances to the end of the waveguide. [32] Cables with the following characteristics: a detachable connector (160) according to one of claims 1 to 23, and a flexible waveguide (100) according to one of claims 24 to 31. [33] Quantum computer (300), with the following features: a quantum processor (302), a signal generator and / or signal evaluator (304), and at least one detachable connector (160) according to one of claims 1 to 23, a flexible waveguide (100) according to one of claims 24 to 31 or a cable according to claim 32 for signal transmission between the quantum processor (302) and the signal generator and / or signal evaluator (304). [34] Quantum computer according to claim 33, wherein the substrate (150) is a substrate of the quantum processor (302) or the signal generator and / or signal evaluator (304). [35] Quantum computer according to one of claims 33 to 34, 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 designed to operate at a cryogenic temperature or a non-cryogenic temperature.

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