Microwave waveguide device

Abstract

Microwave waveguide device including a supporting substrate including at least one edge, a plurality of ground planes, a transmission line configured to receive and propagate an input signal, the transmission line extending meandering and including turns 17 located at a separation distance the edge, a clearance area located between the turns and the edge. Each turn is located outside the clearance area, and each successive turn is located at a separation distance from the edge to define a plurality of successive separation distances where each successive separation distance has a different separation distance value.

Description

[0001] P4320PC00 6.2652

[0002] MICROWAVE WAVEGUIDE DEVICE

[0003] CROSS-REFERENCE TO RELATED APPLICATIONS

[0004] The present patent application claims priority to European Patent Application EP25164232.8 that was filed on March 17th, 2025, the contents thereof herewith incorporated by reference in its entirety.

[0005] FIELD OF THE INVENTION

[0006] The present invention relates to the field of microwave engineering and, more specifically, to waveguide structures, microwave waveguide structures and techniques for mitigating unwanted stopbands in periodic microwave waveguides by introducing controlled randomization of turning points and ground connections.

[0007] BACKGROUND

[0008] Periodic microwave waveguides, such as coplanar waveguides (CPWs) and microstrip transmission lines, often exhibit unwanted stopbands due to periodic impedance mismatches, which can degrade signal integrity and performance in high-frequency applications.

[0009] These stopbands arise from Bragg reflections occurring at periodic discontinuities in the waveguide structure.

[0010] Conventional approaches to mitigate these effects include the use of tapered transitions or additional filtering structures, but these methods often introduce unwanted design complexity and fabrication challenges.

[0011] The article “A near-quantum-limited Josephson traveling-wave parametric amplifier”, Macklin Chris et al., Science 350, no. 6258 (2015): 307-310, the article “A dispersion-engineered Josephson travelling wave parametric amplifier with periodic impedance perturbation”, Ratter Kitti, et al., National Radio Astronomy Observatory, (2021), and the conference proceedings: “Progress towards a near quantum-limited Josephson travelling wave parametric amplifier based on Nb-AI / Al2O3-Nb trilayer technology”, E. Guzovskii, et al., APS March meeting (2023) disclose an exemplary microwave waveguide that form an amplifier and whose dispersion can also contain such unwanted stopbands. The disclosure of each one of the above documents is hereby incorporated herein by reference in its entirety for all purposes,P4320PC00 6.2652

[0012] The present disclosure provides a waveguide device or structure to overcome the above-mentioned problem of unwanted stopbands.

[0013] The present disclosure provides an innovative approach to eliminating unwanted stopbands in the waveguide structure, thereby disrupting the formation of strong Bragg reflections while maintaining low transmission loss.

[0014] SUMMARY

[0015] Certain example embodiments herein are provided to overcome the above problem. According to one aspect of the present invention, a waveguide device is provided.

[0016] The microwave waveguide device may include at least one supporting substrate or layer, the at least one supporting substrate or layer may include at least one edge delimiting at least one outer perimeter of the microwave waveguide device; at least one or a plurality of electrical ground planes provided on the at least one supporting substrate or layer; at least one transmission line and / or at least one signal line / conductor configured to receive and propagate at least one input signal, the at least one transmission line and / or the at least one signal line extending meandering on the at least one supporting substrate or layer towards and away from the at least one edge, wherein the at least one transmission line and the at least one signal line may include a plurality of turns located at a separation distance from the at least one edge, each turn permitting an extension of the at least one transmission line and / or the at least one signal line towards the at least one edge to change direction to extend away from the at least one edge. The microwave waveguide device may include at least one clearance area located between the plurality of turns and the at least one edge, the at least one clearance area being configured for receiving a plurality of wire bonds. Each turn may be located outside the at least one clearance area.

[0017] Each successive turn may be located at a separation distance SD from the at least one edge to define a plurality of successive separation distances SD1... SDX, wherein each successive separation distance SD1... SDX has a different separation distance value.

[0018] Alternatively or additionally, each successive separation distances SD1... SDX may have a different separation distance value to prevent the generation of at least one parasitic stopband in a dispersion of the at least one transmission line and produced when periodically repeating values of the successive separation distance are present.P4320PC00 6.2652

[0019] Alternatively or additionally, an outermost extremity of each turn located opposite the edge may be located at a different and non-periodic repeating distance value relative to the edge.

[0020] Alternatively or additionally, an outermost extremity of each turn located opposite the edge may be located at a random distance value from the edge.

[0021] Alternatively or additionally, the plurality of values of the successive separation distances SD1... SDX may form a set of randomized values of the separation distance SD.

[0022] The at least one supporting substrate or layer may include at least a first edge delimiting a first outer perimeter of the microwave waveguide device and at least a second edge delimiting a second outer perimeter of the microwave waveguide device. The first edge may be located opposite the second edge and at an edge separation distance CD from the second edge. The at least one transmission line and / or the at least one signal line / conductor may include a plurality of elongated extensions each extending an extension length LN between the first and second edges, where LN may have a value: CD x 0.5 < LN < CD x 0.95, or CD x 0.75 < LN < CD x 0.9.

[0023] Further advantageous features are provided in the dependent claims.

[0024] The present disclosure permits to eliminate or reduce unwanted stopbands by introducing controlled randomization of the turning points and / or ground connections in the waveguide structure, thereby disrupting the formation of strong Bragg reflections while maintaining low transmission loss.

[0025] The present disclosure concerns microwave waveguides and introduces a technique to mitigate stopbands in periodic microwave waveguides by incorporating controlled disorder in the positioning of turning points and / or ground connections.

[0026] The method or approach may involve, for example, a systematic randomization of key geometrical parameters, preventing the formation of strong periodic resonance conditions that lead to stopbands. The proposed approach can be implemented in superconducting or normalconducting microwave circuits and is particularly beneficial for quantum computing, signal processing, and high-speed communication applications.P4320PC00 6.2652

[0027] The above and other objects, features and advantages of the present invention and the manner of realizing them will become more apparent, and the invention itself will best be understood from a study of the following description with reference to the attached drawings showing some preferred embodiments of the invention.

[0028] BRIEF DESCRIPTON OF THE DRAWINGS

[0029] The accompanying drawings, which are incorporated herein and constitute part of this specification, illustrate the presently preferred embodiments of the invention, and together with the general description given above and the detailed description given below, serve to explain features of the invention. Like reference numerals may refer to like parts throughout the several views. Each embodiment herein may be used in combination with any other embodiment(s) described herein. Also, the images are simplified for illustration purposes and may not be depicted to scale.

[0030] Figure 1A shows a known microwave waveguide structure or device comprising a Josephson Traveling Wave Parametric Amplifier that meanders periodically and which exhibit unwanted stopbands due to spatially periodic structures which can degrade signal integrity and performance.

[0031] Figure 1 B shows an exemplary microwave waveguide structure or device according to the present disclosure comprising a randomization in the positioning of turning points and / or ground connections. Air-bridges are not illustrated to assure improved legibility.

[0032] Figure 2 shows transmission of a microwave waveguide structure or device in which a randomization in the positioning of turning points is introduced compared to a microwave waveguide structure or device in which the positioning of turning points is periodic.

[0033] Figure 3 shows transmission of a microwave waveguide structure or device comprising a traveling-wave parametric amplifier (TWPA) without any randomized structure, and Figure 4 shows the transmission in accordance with the improved design of the present disclosure with randomized turning points. When the amplifier is turned on, gain can be measured over a large frequency span.

[0034] Figure 5 shows low insertion loss and a comparison of transmitted signals. The signal that is transmitted through the amplifier of the present disclosure and through the coaxial cable show almost no insertion loss. Therefore, this amplifier of the present disclosure can be used when OFF.P4320PC00 6.2652

[0035] Figure 6A is a magnified view of a portion of the microwave waveguide structure or device encircled approximately by the dashed oval in Figure 1B.

[0036] Figures 6B and 6C schematically show an exemplary turn of the microwave waveguide structure or device.

[0037] Figure 7 shows an exemplary unit cell of an exemplary coplanar waveguide (CPW) periodically loaded with Josephson junctions.

[0038] Figure 8A is a magnified view of a portion of the microwave waveguide structure or device similar to Figure 6A that shows exemplary bridging connections. Figures 8B shows an air bridge located in close proximity to a shunting capacitor. Figure 8C schematically shows a cross-sectional view of a connection bridge.

[0039] BRIEF DESCRPTION OF THE SEVERAL EMBODIMENTS

[0040] The present disclosure concerns, for example, a microwave waveguide structure or device, for example, composed by or including a number N of periodic elements connected in series.

[0041] Usual microwave chip size implies a meandering geometry for long waveguide (see Figure 1 A). This implies a turning point with a precise distance on from the chip edge. This produces an effective periodicity with a consequent unwanted microwave stopband (see arrow of Figure 2).

[0042] In addition, microwave engineering requires to equalize ground connection each tenth of wavelength. Therefore, according to the present disclosure, additional ground connections (for example air bridges) are, for example, intentionally randomized within a predefined statistical distribution. Elements of the present disclosure permitting to address the inconvenience of an unwanted microwave stopband include:

[0043] Randomized Turning Points:

[0044] o The locations of bends or meanders in the waveguide are varied within a constrained range, preventing the formation of periodic resonance conditions that cause unwanted stopbands.

[0045] o The statistical distribution of these variations is optimized to minimize transmission loss while disrupting coherent reflections.P4320PC00 6.2652

[0046] Randomized Ground Connections:

[0047] o In waveguides with ground connections, such as CPWs, the positions of ground vias or coupling elements are randomized.

[0048] o This prevents the periodic formation of mode-matching conditions that lead to strong reflective bands.

[0049] Fabrication and Implementation:

[0050] o The method can be implemented using standard lithographic and etching techniques, and / or using known materials.

[0051] o It is compatible with superconducting circuits, allowing improved coherence and signal fidelity in quantum devices.

[0052] o The degree of randomness can be tuned based on the application requirements, ensuring that beneficial transmission properties are preserved.

[0053] Applications of the microwave waveguide structure or device of the present disclosure include:

[0054] • Superconducting quantum circuits

[0055] • High-frequency RF and microwave communications

[0056] • Low-loss signal transmission in integrated circuits

[0057] • High-precision sensing and metrology

[0058] This present disclosure provides an innovative device and method for mitigating unwanted stopbands in periodic microwave waveguides through controlled randomization of turning points and ground connections. By disrupting periodic resonance conditions, this approach enhances signal integrity and reduces performance degradation, making it highly advantageous for various high-frequency applications.

[0059] One exemplary embodiment concerns a Parametric Amplifier, or an Impedance Modulated Josephson Traveling Wave Parametric Amplifier JTWPA.

[0060] A Josephson traveling wave parametric amplifier JTWPA design may, for example, comprise or be composed of a transmission line, for example, a linear 50 Ohm CPW (coplanar waveguide) transmission line, with periodically loaded high impedance nonlinear Josephson transmission lines.P4320PC00 6.2652

[0061] By designing the periodicity of the circuits, stop bands around the pump frequency and integer times of pump frequency could be created to achieve phase matching and suppress the propagation of the higher harmonics. Of importance, the inventors introduced randomized turning points for the waveguide on a chip, which effectively removed additionally unintentional periodicity in the waveguide.

[0062] Designing the nonlinear transmission line at, for example, 50 Ohm requires a large, shunted capacitance per unit cell and is typically achieved by using parallel plate capacitors based on lossy dialectic material, for example, SiO2, Al2O3or Si3N4. In an exemplary design, the nonlinear transmission line is designed to be with high impedance, which reduces the required capacitor per unit cell to only approximately 10 fF and can be easily achieved using planar capacitors with loss tangent two or three orders of magnitude less than the aforementioned dielectric materials. This implies lower added noise and higher quantum efficiency which is the most critical figure of merit for amplifiers.

[0063] The performance of this JTWPA will also be much more robust to the fabrication variations. The impedance of the JTWPAs based on the parallel plate capacitors are determined by the thickness of the dielectric material and the critical current of Josephson junctions. However, the impedance of JTWPA in this design is mostly determined by the linear CPW and can be easily matched to 50 Ohm by changing the geometric parameters.

[0064] The Josephson traveling wave parametric amplifier design achieves high amplification with impedance modulated structures in, for example, CPW geometries. Impedance modulation opens a band-stop SB that can be utilized to phase match the 4-wave mixing parametric amplification process. Moreover, the nonlinearity of the Josephson junction will serve as the active mixing element.

[0065] In particular, compared to the state of the art, the solution of the present disclosure can solve two problems: It removes the additional periodic features from structures that span many (>20) wavelengths; and It removes the necessity to use TWPA amplifiers ON, as also when they are not pumped the insertion loss limits greatly the signal transmission.

[0066] The advantages compared to similar devices are as follows: It reduces the insertion loss of the Josephson traveling wave parametric amplifier; thus reducing the added noise and improving theP4320PC00 6.2652

[0067] quantum efficiency of the JTWPA, as well as potentially increasing the squeezing ability when using the JTWPA as either single mode or two mode squeezing source. It reduces the fabrication complexity (no need to deposit dielectric material). The performance will be more robust to the fabrication variations, since the impedance is mostly determined by the linear CPW transmission line which can be precisely controlled by the design.

[0068] All previous JTWPA designs are based on fully nonlinear transmission line. It is surprising that using a circuit composed of both linear and nonlinear transmission lines can be used as a traveling wave parametric amplifier. It is also surprising that the capacitors required per unit cell of the nonlinear transmission line is only around 10 fF, which can be easily achieved by the planar capacitors. Finally, it is not expected that long transmission lines in superconducting circuits are affected by the turning position of features that periodically repeat far from each other.

[0069] The full chip design may include two main characteristics (see Figure 1):

[0070] • Randomize turning points (to avoid additional periodicity in the waveguide)

[0071] • Minimization of JJ island capacitor extension (to minimize the linear inductance)

[0072] The randomized turning points and the planar capacitors removes spurious stop band in the transmission spectrum and greatly reduces insertion losses (respectively).

[0073] Figures 1B and 6A shows an exemplary waveguide structure or device 1 according to the present disclosure. The waveguide structure or device 1 may, for example, be a microwave waveguide structure or device 1. The waveguide structure or device 1 may, for example, form or be an electronic chip.

[0074] The waveguide structure or device 1 may, for example, include and / or form a parametric amplifier such as a Josephson traveling wave parametric amplifier JTWPA or an impedance modulated Josephson traveling wave Parametric amplifier JTWPA.

[0075] The waveguide structure or device 1 may, for example, include the randomized turning points and / or randomized ground connections.

[0076] The waveguide structure or device 1 may include at least one supporting substrate or layer 3. The supporting substrate or layer 3 includes at least one edge 5A delimiting at least one outerP4320PC00 6.2652

[0077] perimeter of the microwave waveguide device 1, or include a plurality of edges 5A, 5B, 5C 5D delimiting a plurality of perimeters or perimeter sections of the microwave waveguide device 1 (see, for example, Figures 1B and 6A). In a non-limiting exemplary embodiment, the supporting substrate or layer 3 may for example comprise silicon.

[0078] The waveguide structure or device 1 includes at least one or a plurality of electrical ground planes 7 provided on the supporting substrate or layer 3.

[0079] The waveguide structure or device 1 includes at least one transmission line 9 and at least one signal line 11 configured to receive and propagate an input signal IS. The transmission line 9 and the signal line 11 extends to meander on the supporting substrate or layer 3.

[0080] The transmission line 9 and the signal line 11 extend towards and away from the edge or edges 5, for example, towards and away from first and second edges 5A, 5B. The transmission line 9 and the signal line 11 may extend between a signal input extremity 15A and a signal output extremity 15B of the transmission line 7 and the signal line 9 while meandering via a plurality of turns or bends 17, for example, between the first and second edges 5A, 5B.

[0081] The microwave waveguide device 1 and / or the transmission line 9 may, for example, comprise and / or be formed by a coplanar waveguide geometry or by a microstrip geometry in some embodiments.

[0082] The transmission line 9 and the signal line 11 include the plurality of turns 17, and each turn 17 is located at a separation distance SD from the edge 5, 5A, 5B. The separation distance SD is, for example, defined between an outermost extremity 19 of the turn 17 and the edge 5.

[0083] Each turn 17 permits the transmission line 9 and the signal line 11, that extend towards the edge 5, or first edge 5A, 5B to change direction and to extend away from the edge 5 in the direction of another opposing edge 5A, 5B.

[0084] The plurality of turns 17 permit the transmission line 9 and the signal line 11 to extend across the supporting substrate or layer 3 in a meandering manner, for example, and extend between the signal input extremity 15A and the signal output extremity 15B of the transmission line 7 and the signal line 9. The transmission line 7 and the signal line 9 extend, for example, between third andP4320PC00 6.2652

[0085] fourth edges 5C, 5D via the plurality of turns 17 that direct the extension of the transmission line 7 and the signal line 9 to and from the first and second edges 5A, 5B.

[0086] The waveguide structure or device 1 includes, for example, at least one clearance area 21, or at least first and second clearance areas 21 A, 21 B. The or each clearance area 21 is, for example, located between the plurality of turns 17 and the edge 5. The clearance area 21 is configured to receive a plurality of wire bonds or wire bonding of the waveguide structure or device 1.

[0087] In an exemplary embodiment, clearance area(s) 21 includes a plurality of wire bonds or wire bonding (not shown) located between the edge 5 and the plurality of turns 17.

[0088] Each turn 17 is, for example, located outside the clearance area 21, or outside each clearance area 21 A, 21 B. The or each clearance area 21 is turn-free.

[0089] The or each clearance area 21 A, 21 B includes a clearance distance CLD extending in a direction from the edge 5 towards the plurality of turns 17. For example, 200 microns < CLD < 500 microns, or preferably for example 250 microns < CLD < 400 microns. In an exemplary embodiment, CLD is about 300 microns.

[0090] Each successive turn 17 may, for example, be located at a separation distance SD from the edge 5, 5A, 5B to define a plurality of successive separation distances SD1... SDX. Figure 6A shows for illustration purposes, successive separation distances SD1 to SD10.

[0091] In an exemplary embodiment, each successive separation distance SD1... SDX has a different separation distance value.

[0092] The outermost extremity 19 of each turn 17 is located at a different and non-periodic repeating distance value relative to the edge 5, 5A, 5B, and / or at a random distance from the edge 5, 5A, 5B.

[0093] Each successive separation distances SD1... SDX has, for example, a different separation distance value to prevent the generation of an unwanted or parasitic stopband 23 (see, for example, Figure 3) in a dispersion of the transmission line 9. The stopband 23 is, for example,P4320PC00 6.2652

[0094] produced when periodically repeating values of the successive separation distance SD are present.

[0095] With respect to a Josephson travelling wave parametric amplifier, the frequency stopband 23 or parasitic stopband 23 is located outside an operational frequency stopband or phase matching frequency stopband SB (see, for example, Figures 3 and 4) used for in the 3-wave or 4-wave mixing process to align the pump and signal to amplifiy the input signal IS.

[0096] In an exemplary embodiment, the plurality of values of the successive separation distances SD1... SDX forms a set of randomized values of the separation distance SD.

[0097] The values of the successive separation distances SD1... SDX have, for example, random number values.

[0098] The permits the previously mentioned randomized turning points or randomized locations of the turns to be included.

[0099] The locations of the turns 17 vary within a constrained or defined range, and the locations are such as to prevent the formation of periodic resonance conditions that cause the unwanted stopband 23 in a dispersion of the transmission line 9. The locations of the turns 17 are, for example, located at different locations according to a statistical distribution to minimize transmission loss while disrupting coherent reflections.

[0100] As mentioned, the supporting substrate or layer 3 includes, for example, at least a first edge 5A delimiting a first outer perimeter of the microwave waveguide device 1 and at least a second edge 5B delimiting a second outer perimeter of the microwave waveguide device 1. The first edge 5A is, for example, located opposite the second edge 5B and, for example, can be located at an edge separation distance CD from the second edge 5B (see, for example, Figure 1B).

[0101] In an exemplary embodiment, the transmission line 9 and the signal line 11 include a plurality of elongated extensions 25 (see, for example, Figure 1B and Figures 6A to 6C). Each elongated extensions 25 extends, for example, an extension length LN between the first and second edges 5A, 5B. The extension length LN is for example, CD x 0.5 < LN < CD x 0.95, or preferably CD xP4320PC00 6.2652

[0102] 0.75 < LN < CD x 0.9. As mentioned, CD is the edge separation distance CD, for example, between the first and second edges 5A, 5B.

[0103] This permits the length LN of the sections 25 to be long and the turns 17 to be located close to the edge 5 while also being located outside the clearance area 21. This allows to reduce or minimize the area occupied by the transmission line 9 and the signal line 11 on supporting substrate or layer 3 and / or the device 1.

[0104] Each turn 17 may, for example, have a turn radius R (see, For example Figures 6A to 6C). Each turn 17 may, for example, comprise or have at least one or a plurality of interconnection sections 27A, 27B interconnecting first and second turn sections 29A, 29B forming each turn 17 (see, for example, Figure 6C).

[0105] The at least one or the plurality of interconnection sections 27A, 27B and the turn sections 29A, 29B forming each turn 17 are thus located outside the clearance area 21.

[0106] In an exemplary embodiment, each turn 17 has substantially the same or about the same turn radius value R. Each interconnection section may, for example, have substantially the same length, or be of about the same length (for example, in the X-direction, or direction perpendicular to the elongated direction of extension of the elongated extensions 25 or signal line 11).

[0107] In an exemplary embodiment, each of the first and second turn sections 27A, 27B may form, for example, a 90-degree bend permitting the turn 17 to change direction by 180 degrees.

[0108] One exemplary implementation method of deployment of the transmission line 9 and the signal line 11 along the supporting substrate or layer 3 may, for example, comprise generating a list of random numbers using a normal distribution with a mean value (determined by the device 1 or chip size) and a variation of, for example, 90 pm to dictate the length of the sections 25 in the Y-direction. It is then verified if the generated numbers satisfy the clearance area 21 constraint (and any other constraints), with the process repeating until a valid list was found.

[0109] An alternative exemplary and more efficient method is to generate the meandered transmission line 9 and the signal line 11 along the supporting substrate or layer 3 piece by piece. It is firstly calculated whether extending in a straight line along the Y-direction will place the transmissionP4320PC00 6.2652

[0110] line 9 and the signal line 11 and junction-loaded regions too close to the chip edge 5. If a turn 17 is required, a permissible range for the length of that straight section 25 is determined so that it satisfies the constraints, while also ensuring it doesn't turn prematurely when still far from the edge 5. One then selects a random value within this permissible range, execute the turn 17, and track this position of the turn 17 for determining the next turn 17.

[0111] The microwave waveguide device 1 may include, for example, a plurality of electrical ground connections 30. The electrical ground connection may, for example, comprise a bridging connection or an air-bridge 30 (see, for example, Figure 8A). The plurality of electrical ground connections may form connections between a plurality of electrical ground planes 7. In a preferred embodiment, each turn 17 is, for example, electrical ground connection-free (see, for example, Figure 8A). That is, electrical ground connections are absent from a location where the or each turn 17 is positioned or located. That is, the electrical ground connection is absent from the locations of the at least one or the plurality of interconnection sections 27A, 27B and the turn sections 29A, 29B forming each turn 17.

[0112] Airbridges 30 does not overlap with the interdigital (IDT) capacitors to the ground. Airbridges 30 are located to non-overlap with sections of the ground plane 7 forming a portion of the capitor 31. Airbridges 30 are located at a distance away from to the capitor 31 to avoid shorting or short circuiting between the airbridge 30 and the capaitor 31. Figure 8C shows an exmplple where an airbridge 30 is positioned too close to the capitor 31 and results in a significant risk of short circuiting. Figure 8C shematically cross-sectionaly shows an airtbridge 30 connecting ground planes 7.

[0113] The electrical ground connections of the plurality of electrical ground connections are, for example, located in a spatially non-periodic arrangement. As mentioned, the electrical ground connections are, for example, non-spatially overlapping with electrical ground connections of capacitors 31, of the microwave waveguide device 1.

[0114] Each successive electrical ground connection may, for example, be separated by a ground connection separation distance, and each ground connection separation distance has a different value. The plurality of values of the successive ground connection separation distances may, for example, form a set of randomized values of the ground connection separation distance.P4320PC00 6.2652

[0115] The positions of airbridges or coupling elements are, for example, randomized. The electrical ground connections are, for example, arranged and / or configured to prevent the periodic formation of mode-matching conditions that lead to strong reflective bands.

[0116] This provides a waveguide structure or device 1 including randomized ground connections.

[0117] An exemplary implementation method for deployment of the electrical ground connections may include, for example, the distance (along the signal path 11) between two electrical ground connections or airbridges being assigned a random number value between for example 600 pm and 800 pm (this range is adjusted based on the speed of light inside the waveguide and the frequency range of interest). After selecting a random distance value, it is verified if the constraint(s) (non-overlap and / or exclusion from turn location) are satisfied. If not, the position of the electrical ground connection or airbridge is shifted or displaced by a predetermined distance, for example, ±100 pm along the signal path 11 until the constraint(s) are met.

[0118] In one exemplary embodiment of the present disclosure, the microwave waveguide device 1 includes and / or forms a Josephson travelling wave parametric amplifier 33.

[0119] The Josephson travelling wave parametric amplifier 33 is, for example, configured to provide or generate the stopband SB in the dispersion of the transmission line and in which the input signal IS can be amplified via a three-wave mixing process or a four wave-mixing process. The Josephson travelling wave parametric amplifier 33 is, for example, configured to parametrically amplify the input signal IS based, for example, on either a four-wave mixing process where four photons are involved and two pump photons are combined to provide an idler photon and a photon having a frequency of the input signal IS, or a three-wave mixing process involving an interaction of three photons.

[0120] The Josephson travelling wave parametric amplifier 33 includes the transmission line 9 and the signal line 11 that are configured to receive and propagate the input signal IS to amplify the input signal IS (see, for example, Figure 7). The transmission line 9 and the signal line 11 including a plurality of Josephson junctions JJ connected in series to form portions of the transmission line 9. The amplifier 33 also includes the at least one or the plurality of electrical ground planes 7, and a plurality of shunting capacitors 31 shunting the transmission line 9 and the signal line 11 to the at least one or to the plurality of electrical ground planes 7.P4320PC00 6.2652

[0121] In an exemplary embodiment, each turn 17 may, for example, be Josephson junction-free, and / or each turn 17 may be shunting capacitor-free. That is, Josephson junctions JJ may be absent from a location where the or each turn 17 is positioned or located and / or shunting capacitors may be absent from a location where the or each turn 17 is positioned or located. The Josephson junction JJ and / or the capacitor 31 may be absent from the locations of the at least one or the plurality of interconnection sections 27A, 27B and the turn sections 29A, 29B forming each turn 17.

[0122] The Josephson junction may, for example, comprise an AI / AIOx / AI Josephson junction, or for example a Nb / AI-AIOx / Nb junction.

[0123] In an alternative embodiment, the Josephson junction and / or the shunting capacitor may located at the location of a turn 17. A subtractive fabrication process may, for example, be used to provide the Josephson junction and / or the shunting capacitor located on the turn(s) 17.

[0124] Figure 7 shows an exemplary single unit cell 35 of an exemplary amplifier 33 periodically loaded with Josephson junctions JJ.

[0125] A single unit cell 35 may, for example, comprise three sub-cells SC1, SC2, SC3.

[0126] A first sub-cell SC1 may comprise a linear waveguide for example a linear CPW having a characteristic impedance Z0(designed for example to be 50 Ohms) and a length 11 (corresponding for approximately to A / 6 at a designed pump frequency). This is followed by a short, lumped-element transmission line comprising of Josephson junctions JJ and capacitors 31 connected to ground 7. This lumped-element section has a characteristic impedance Z1, different from 50 Ohms.

[0127] The second sub-cell SC2 can be, for example, identical to the first sub-cell SC1. The third subcell SC3 can, for example, be similar to the first sub-cell SC1, except it can contain fewer Josephson junctions JJ and capacitors 31, for example, two Josephson junctions JJ and two capacitors 31.

[0128] This entire unit cell 35 can be repeated multiple times, for example, 70 to 130 times depending on the chip size, and the amount of gain to be provided on the chip.P4320PC00 6.2652

[0129] This periodic structure creates the stopband SB at the designed frequency to permit to achieve phase matching between the pump signal and idler to enable parametric amplification.

[0130] Meandering is used the reduce the amount of space occupied on the chip and to reduce chip size and area.

[0131] Another aspect of the present disclosure concerns a circuit including the microwave waveguide device 1.

[0132] The microwave waveguide device 1 or portions thereof may, for example, be fabricated using deep ultraviolet DUV lithography. The microwave waveguide device 1 may, for example, be a DUV lithography fabricated device.

[0133] The edge 5 may, for example, extends to define a chip. The dimensions of the chip may, for example, be less than that of a reticle of a stepper that is used to produce the DUV lithography fabricated device.

[0134] Exemplary materials that may be used to form the waveguide structure or device 1 and the superconducting circuit may include at least one of:

[0135] Superconducting Materials: Niobium [1,2], Aluminum [3,4], Tantalum [5] and Rhenium [6,7],

[0136] High Kinetic Inductance materials: NbN

[0010] , NbTiN [8], TiN [9], TaN

[0014] , Granular Aluminum

[0011] , Tungsten Silicide

[0012] , Molybdenum Silicide

[0013] .

[0137] Figure 3 shows a Transmission of a TWPA without any randomized structure, and Figure 4 shows the improved design of the present disclosure with randomized turning points 17. When the amplifier 33 is turned on, the gain can be measured over a large span.

[0138] Figure 5 shows Low insertion loss: the comparison of transmitted signal. The signal that is transmitted through the TWPA and the coaxial cable show almost no insertion loss. Therefore, this amplifier can be used when OFF.

[0139] The measured spectrum of the device without the advantageous features of the presentP4320PC00 6.2652

[0140] disclosure is visible on Figure 3. An additional stop band at 7.5GHz limits the amplifier performance. In Figure 4 the device with the invention implemented: only a single stopband is present in the amplifier band. In addition, the amplifier has an average of 5dB gain over a GHz span.

[0141] Finally, this amplifier 33 can be also used without any pump on. In Figure 5 the comparison between the transmission through a coaxial cable and our amplifier show no difference. This is a unique feature of our amplifier enabled by extremely low insertion losses.

[0142] It is to be understood that terms such as “first”, “second”, or “first” or “second” may simply be used to distinguish the component from other components in question, and do not limit the components in other aspects (e.g., importance or order). Terms, such as “first”, “second”, and the like, may be used herein to describe various components. Each of these terminologies is not used to define an essence, order or sequence of a corresponding component but used merely to distinguish the corresponding component from other component(s). For example, a "first" component may be referred to as a "second" component, and similarly, the "second" component may be referred to as the "first" component.

[0143] It should be noted that if it is described that one component is "connected", "coupled", or "joined" to another component, at least a third component(s) may be "connected", "coupled", and "joined" between the first and second components, although the first component may be directly connected, coupled, or joined to the second component. Thus, terms such as “connected” and “coupled” cover both direct and indirectly connections and couplings.

[0144] It will be further understood that the terms "comprises / comprising" and / or "includes / including" when used herein, specify the presence of stated features, integers, steps, operations, elements, and / or components, but do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components and / or populations thereof.

[0145] The word “about” as used herein means the identified value plus / minus 5%.

[0146] “On” as used herein covers both directly on, and indirectly on with intervening element(s) therebetween. Thus, for example, if element A is stated to be “on” element B, this covers element A being directly and / or indirectly on element B. Likewise, “supported by” as used herein coversP4320PC00 6.2652

[0147] both in physical contact with, and indirectly supported by with intervening element(s) therebetween.

[0148] Each embodiment herein may be used in combination with any other embodiment(s) described herein.

[0149] While the invention has been disclosed with reference to certain preferred embodiments, numerous modifications, alterations, and changes to the described embodiments, and equivalents thereof, are possible without departing from the scope of the invention. Accordingly, it is intended that the invention not be limited to the described embodiments, and be given the broadest reasonable interpretation in accordance with the language of the appended claims.

[0150] REFERENCES

[0151] 1. Kono, S., Pan, J., Chegnizadeh, M., Wang, X., Youssefi, A., Scigliuzzo, M. and Kippenberg, T. J., 2024. Mechanically induced correlated errors on superconducting qubits with relaxation times exceeding 0.4 ms. Nature Communications, 15(1), p.3950.

[0152] 2. Macklin, C., O’brien, K., Hover, D., Schwartz, M. E., Bolkhovsky, V., Zhang, X., Oliver, W. D.

[0153] and Siddiqi, I., 2015. A near-quantum-limited Josephson traveling-wave parametric amplifier. Science, 350(6258), pp.307-310.

[0154] 3. Chang, C. S., Van Loo, A. F., Hung, C. C., Zhou, Y., Gnandt, C., Tamate, S. and Nakamura, Y., 2025. Josephson traveling-wave parametric amplifier based on a low-intrinsic-loss lumped-element coplanar waveguide. Physical Review Applied, 24(4), p.044081.

[0155] 4. Wang, J., Peng, K., Knecht, J. M., Cunningham, G. D., Lombo, A. E., Yen, A., Zaidenberg, D. A., Gingras, M., Niedzielski, B. M., Stickler, H. and Sliwa, K., 2025. High-efficiency, low- loss Floquet-mode traveling wave parametric amplifier. arXiv preprint arXiv:2503.11812.

[0156] 5. Bland, M. P., Bahrami, E, Martinez, J. G., Prestegaard, P. H., Smitham, B. M., Joshi, A., Hedrick, E., Kumar, S., Yang, A., Pakpour-Tabrizi, A. C. and Jindal, A., 2025. Millisecond lifetimes and coherence times in 2D transmon qubits. Nature, pp.1-6.

[0157] 6. Crisa, F., Lee, J., Garattoni, S., Zhu, S., Clairmont, A., Grassellino, L., Murthy, A., Romanenko, A., Bal, M. and Grassellino, A., 2025. High-Quality Factor Microwave Resonators using Rhenium (No. FERMILAB-SLIDES-25-0039-SQMS). Fermi National Accelerator Laboratory (FNAL), Batavia, IL (United States).P4320PC00 6.2652

[0158] 7. Tarkaeva, E. V., Ievleva, V. A., Prishchepa, A. R., Zhukova, E. S., Terentiev, A. and Kuntsevich, A. Y., 2025. High-performance amorphous superconducting rhenium films by e-beam evaporation. Journal of Applied Physics, 138(12).

[0159] 8. Malnou, Maxime, M. R. Vissers, J. D. Wheeler, Joe Aumentado, Johannes Hubmayr, J. N.

[0160] Llom, and Jiansong Gao. " Three-wave mixing kinetic inductance traveling-wave amplifier with near-quantum-limited noise performance.” PRX quantum 2, no. 1 (2021): 010302.

[0161] 9. Longden, J., Chaumont, C., Klimovich, N., Wood, S., Boussaha, F. and Tan, B. K., 2025.

[0162] Preliminary characterisation of titanium nitride kinetic inductance travelling-wave parametric amplifiers. Open Research Europe, 5, p.109.

[0163] 10. Adamyan, A. A., De Graaf, S. E., Kubatkin, S. E. and Danilov, A. V., 2016. Superconducting microwave parametric amplifier based on a quasi-fractal slow propagation line. Journal of Applied Physics, 119(B).

[0164] 11. Zapata, N., Takmakov, I., Glinzler, S., Geisert, S., Ihssen, S., Field, M., Nambisan, A., Rieger, D., Reisinger, T., Wernsdorfer, W. and Pop, I. M., 2024. Granular aluminum parametric amplifier for low-noise measurements in tesla fields. Physical Review Letters, 133(26), p.260604.

[0165] 12. Goldstein, S., Kirsh, N., Svetitsky, E., Zamir, Y., Hachmo, O., De Oliveira, C. E. I. and Katz, N., 2020. Four wave-mixing in a microstrip kinetic inductance travelling wave parametric amplifier. Applied Physics Letters, 116(15).

[0166] 13. Cecil, T, Miceli, A., Quaranta, O., Liu, C., Rosenmann, D., McHugh, S. and Mazin, B., 2012. Tungsten silicide films for microwave kinetic inductance detectors. Applied Physics Letters, 101(3).

[0167] 14. Ithepalli, A., Rajapurohita, A. R., Singh, A., Singh, R., Wright, J., Rana, F., Fatemi, V., Xing, H. G. and Jena, D., 2025. Structural, electronic, and superconducting properties of MBE- grown tantalum nitride films on c-plane sapphire. Applied Physics Letters, 126(22).

Claims

P4320PC00 6.2652CLAIMS1. Microwave waveguide device (1) including:at least one supporting substrate or layer (3), the at least one supporting substrate or layer (3) including at least one edge (5) delimiting at least one outer perimeter of the microwave waveguide device (1);at least one or a plurality of electrical ground planes (7) provided on the at least one supporting substrate or layer (3);at least one transmission line (9) and at least one signal line (11) configured to receive and propagate at least one input signal (IS), the at least one transmission line (9) and the at least one signal line (11 ) extending meandering on the at least one supporting substrate or layer (3) towards and away from the at least one edge (5), wherein the at least one transmission line (9) and the at least one signal line (11) include a plurality of turns (17) located at a separation distance (SD) from the at least one edge (5), each turn (17) permitting an extension of the at least one transmission line (9) and the at least one signal line (11) towards the at least one edge (5) to change direction to extend away from the at least one edge (5);at least one clearance area (21 ) located between the plurality of turns (17) and the at least one edge (5), the at least one clearance area (21 ) being configured for receiving a plurality of wire bonds;wherein each turn (17) is located outside the at least one clearance area (21); andwherein each successive turn (17) is located at a separation distance (SD) from the at least one edge (5) to define a plurality of successive separation distances (SD1... SDX), wherein each successive separation distance (SD1... SDX) has a different separation distance value.

2. Microwave waveguide device (1) according to the previous claim, wherein each successive separation distances (SD1... SDX) has a different separation distance value to prevent the generation of at least one parasitic stopband (23) in a dispersion of the at least one transmission line (9) and produced when periodically repeating values of the successive separation distance (SD) are present.

3. Microwave waveguide device (1) according to any one of the previous claims, wherein an outermost extremity (19) of each turn (17) located opposite the edge (5B) is located at a different and non-periodic repeating distance value relative to the edge (5B).P4320PC00 6.26524. Microwave waveguide device (1) according to any one of the previous claims, wherein an outermost extremity (19) of each turn (17) located opposite the edge (5B) is located at a random distance value from the edge (5B).

5. Microwave waveguide device (1) according to any one of the previous claims, wherein the plurality of values of the successive separation distances (SD1... SDX) forms a set of randomized values of the separation distance (SD).

6. Microwave waveguide device (1) according to any one of the previous claims, wherein the at least one supporting substrate or layer (3) includes at least a first edge (5A) delimiting a first outer perimeter of the microwave waveguide device (1) and at least a second edge (5B) delimiting a second outer perimeter of the microwave waveguide device (1), the first edge (5A) being located opposite the second edge (5B) and at an edge separation distance CD from the second edge (5B), wherein the at least one transmission line (9) and the at least one signal line (11) include a plurality of elongated extensions (25) each extending an extension length LN between the first and second edges (5A, 5B), wherein CD x 0.5 < LN < CD x 0.95.

7. Microwave waveguide device (1) according to any one of the previous claims, wherein a plurality of wire bonds is located between the at least one edge (5) and the plurality of turns (17).

8. Microwave waveguide device (1) according to any one of the previous claims, wherein the at least one clearance area (21) includes a clearance distance CLD extending in a direction from the at least one edge (5) towards the plurality of turns (17), wherein 200 microns < CLD < 500 microns.

9. Microwave waveguide device (1) according to any one of the previous claims, wherein each turn (17) has a turn radius (R), and each turn (17) includes at least one interconnection section (27A, 27B) interconnecting first and second turn sections (29A, 29B) forming each turn (17), wherein each turn (17) has about the same turn radius (R), and each of the at least one interconnection sections (27A, 27B) has about the same length.

10. Microwave waveguide device (1) according to the previous claim, wherein each of the first and second turn sections (29A, 29B) form a 90-degree bend.P4320PC00 6.265211. Microwave waveguide device (1) according to any one of the previous claims, wherein the locations of the turns (17) vary within a constrained or defined range, and the locations are such as to prevent the formation of periodic resonance conditions that cause unwanted stopbands (23) in a dispersion of the at least one transmission line (9).

12. Microwave waveguide device (1) according to the previous claim, wherein the locations of the turns (17) are located at different locations according to a statistical distribution to minimize transmission loss while disrupting coherent reflections.

13. Microwave waveguide device (1) according to any one of the previous claims, including a plurality of electrical ground connections (30) forming connections between the at least one or the plurality of electrical ground planes (7), wherein each turn (17) is electrical ground connection-free.

14. Microwave waveguide device (1) according to any one of the previous claims, including a plurality of electrical ground connections (30) forming connections between the at least one or the plurality of electrical ground planes (7), wherein the electrical ground connections of the plurality of electrical ground connections are located in a spatially non-periodic arrangement.

15. Microwave waveguide device (1) according to any one of the previous claims, including a plurality of electrical ground connections (30) forming connections between the at least one or the plurality of electrical ground planes (7), wherein the electrical ground connections are non-spatially overlapping with electrical ground connections of capacitors (31) to the at least one or the plurality of electrical ground planes (7) or are located at a distance from the capacitors (31) that avoids shorting circuiting between the capacitor (31) and the electrical ground connection (30).

16. Microwave waveguide device (1) according to any one of the previous claims, including a plurality of electrical ground connections (30) forming connections between the at least one or the plurality of electrical ground planes (7), wherein each successive electrical ground connection is separated by a ground connection separation distance, and each ground connection separation distance has a different value.P4320PC00 6.265217. Microwave waveguide device (1) according to the previous claim, wherein the plurality of values of the successive ground connection separation distances forms a set of randomized values of the ground connection separation distance.

18. Microwave waveguide device (1 ) according to any one of the previous claims 13 to 17, wherein the electrical ground connection (30) comprises a bridging connection or an air-bridge (30).

19. Microwave waveguide device (1 ) according to any one of the previous claims 13 to 18, wherein positions of ground vias or coupling elements are randomized.

20. Microwave waveguide device (1) according to any one of the previous claims 13 to 19, wherein the electrical ground connections are arranged and / or configured to prevent the periodic formation of mode-matching conditions that lead to strong reflective bands.

21. Microwave waveguide device (1) according to any one of the previous claims, including a Josephson travelling wave parametric amplifier (33), wherein the Josephson travelling wave parametric amplifier (33) includes:- the at least one transmission line (9) and the at least one signal line (11), the at least one transmission line (9) and the at least one signal line (11) being configured to receive and propagate the at least one input signal (IS) to amplify the at least one input signal (IS); the at least one transmission line (9) and the at least one signal line (11 ) including a plurality of Josephson junctions ( J J ) connected in series to form the at least one transmission line (9);- the at least one or the plurality of electrical ground planes (7);a plurality of shunting capacitors (31) shunting the at least one transmission line (9) and the signal line (11) to the at least one or to at least one of the plurality of electrical ground planes (7).

22. Microwave waveguide device (1) according to the previous claim, wherein each turn (17) is Josephson junction-free, and / or each turn (17) is shunting capacitor-free.

23. Microwave waveguide device (1) according to any one of the previous claims 21 to 22, wherein the Josephson travelling wave parametric amplifier (33) is configured to parametrically amplify the at least one input signal (IS) based on a four-wave mixing process wherein fourP4320PC00 6.2652photons are involved and two pump photons are combined to provide an idler photon and a photon having a frequency of the at least one input signal (IS), or a three-wave mixing process involving an interaction of three photons.

24. Microwave waveguide device (1 ) according to any one of the previous claims, wherein the at least one transmission line (9) comprises and / or is formed by a coplanar waveguide geometry or by a microstrip geometry.

25. Microwave waveguide device (1) according to any one of the previous claims, wherein the microwave waveguide device (1) is a deep ultraviolet (DUV) lithography fabricated device, the at least one edge (5) extends to define a chip, and dimensions of the chip are less than that of a reticle of a stepper that produces the deep ultraviolet (DUV) lithography fabricated device.

26. Circuit including the microwave waveguide device (1) according to any one of the previous claims.

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