Irreversible circuit element and quantum computer

Abstract

This irreversible circuit element comprises a conductor, a magnetic body, and an absorber. The conductor is provided with a first terminal and a second terminal, and has a first region that overlaps the magnetic body when viewed from the thickness direction and extends across the first terminal and the second terminal, and a second region that overlaps the absorber when viewed from the thickness direction. The conductor also has recesses and protrusions on the outer periphery when viewed from the thickness direction, and at least some of the recesses and protrusions are located in the second region.

Description

Non-reciprocal circuit elements and quantum computers

[0001] The present disclosure relates to a non-reciprocal circuit element and a quantum computer.

[0002] A non-reciprocal circuit element is an element that determines the transmission direction of a high-frequency signal. Isolators and circulators are examples of non-reciprocal circuit elements. Non-reciprocal circuit elements are widely used in circuits that transmit high-frequency signals.

[0003] Non-reciprocal circuit elements are used in various places where high frequency signals are used. For example, Patent Document 1 discloses an isolator for microwave communication. Also, for example, Patent Document 2 describes the use of an isolator in a quantum computer.

[0004] JP-A-4-287403 Patent No. 6998459

[0005] The non-reciprocal circuit element is placed on a signal line connected to the quantum processor that controls the quantum computer. The quantum processor is placed inside a cryochamber, and the volume of the cryochamber is limited. Therefore, there is a demand for small non-reciprocal circuit elements. One of the characteristics required for non-reciprocal circuit elements is isolation characteristics. There is a demand for non-reciprocal circuit elements with excellent isolation characteristics.

[0006] The present disclosure has been made in view of the above circumstances, and has an object to provide a non-reciprocal circuit element with excellent isolation characteristics.

[0007] In order to solve the above problems, the present invention provides the following means.

[0008] (1) A non-reciprocal circuit device according to a first aspect includes a conductor, a magnetic material, and an absorber. The conductor includes a first terminal and a second terminal. The conductor has a first region that overlaps with the magnetic material and spans the first and second terminals when viewed from the thickness direction, and a second region that overlaps with the absorber when viewed from the thickness direction. The conductor has irregularities on its outer periphery when viewed from the thickness direction, and at least a portion of the irregularities is located in the second region.

[0009] (2) In the non-reciprocal circuit element according to the above aspect, the projections and recesses may be formed by a plurality of straight lines when viewed in the thickness direction.

[0010] (3) In the non-reciprocal circuit element according to the above aspect, the projections and recesses may have at least a part that is curved when viewed in the thickness direction.

[0011] (4) In the non-reciprocal circuit element according to the above aspect, the reference line of the concave and convex portions may not be parallel to a straight line connecting the first terminal and the second terminal.

[0012] (5) In the non-reciprocal circuit element according to the above aspect, at least a part of the irregularities may be present in the first region.

[0013] (6) In the non-reciprocal circuit element according to the above aspect, the projections and recesses may be symmetrical with respect to a center line that passes through the center of a line connecting the first terminal and the second terminal and is perpendicular to the line.

[0014] (7) In the non-reciprocal circuit element according to the above aspect, the projections and recesses may be asymmetric with respect to a center line that passes through the center of a line connecting the first terminal and the second terminal and is perpendicular to the line.

[0015] (8) The non-reciprocal circuit device according to the above aspect may further include a magnetic field source capable of applying a DC magnetic field to the magnetic body.

[0016] (9) A non-reciprocal circuit element according to a second aspect includes a conductor, a magnetic material, and an absorber, wherein the magnetic material and the absorber are each positioned to overlap the conductor in the thickness direction, the conductor has irregularities on at least a portion of its outer periphery, and at least a portion of the irregularities are positioned to overlap the absorber when viewed from the thickness direction.

[0017] (10) A quantum computer according to a second aspect includes the non-reciprocal circuit device according to the above aspect.

[0018] The non-reciprocal circuit device according to the present disclosure has excellent isolation characteristics.

[0019] FIG. 1 is a cross-sectional view of a nonreciprocal circuit device according to the first embodiment. FIG. 2 is a plan view of a conductor and a lossy layer of a nonreciprocal circuit device according to the first embodiment. FIG. 3 is a plan view of a conductor of a nonreciprocal circuit board according to the first embodiment. FIG. 4 is a plan view of a lossy layer of a nonreciprocal circuit board according to the first embodiment. FIG. 5 is a plan view of a grounded body and a magnet of a nonreciprocal circuit board according to the first embodiment. FIG. 6 is a schematic diagram of a quantum computer according to the first embodiment. FIG. 7 is a plan view of a conductor and a lossy layer of a nonreciprocal circuit device according to a first modified example. FIG. 8 is a plan view of a conductor and a lossy layer of a nonreciprocal circuit device according to a second modified example. FIG. 9 is a plan view of a conductor and a lossy layer of a nonreciprocal circuit device according to a third modified example. FIG. 10 is a plan view of a conductor and a lossy layer of a nonreciprocal circuit device according to a fourth modified example. FIG. 11 is a plan view of a conductor and a lossy layer of a nonreciprocal circuit device according to a fifth modified example. FIG. 12 is a plan view of a conductor and a lossy layer of a nonreciprocal circuit device according to a sixth modified example. FIG. 13 is a plan view of a conductor and a lossy layer of a nonreciprocal circuit device according to a seventh modified example. FIG. 14 is a plan view of a conductor and a lossy layer of a nonreciprocal circuit device according to an eighth modified example. FIG. 15 is a measurement result of the insertion loss characteristics of the nonreciprocal circuit devices according to Example 1 and Comparative Example 1. 1 shows measurement results of the reflection loss characteristics of the non-reciprocal circuit devices according to Example 1 and Comparative Example 1. 2 shows measurement results of the isolation characteristics of the non-reciprocal circuit devices according to Example 1 and Comparative Example 1.

[0020] The present embodiment will be described in detail below with reference to the drawings as appropriate. The drawings used in the following description may show characteristic portions enlarged for the sake of clarity, and the dimensional ratios of each component may differ from the actual ones. The materials, dimensions, etc. exemplified in the following description are merely examples, and the present invention is not limited thereto. Appropriate changes can be made within the scope of the effects of the present invention.

[0021] First, let us define directions. The x-direction is the direction along the plane of the conductor. For example, the direction connecting the first terminal T1 and the second terminal T2 of the conductor is the x-direction. The y-direction is the direction perpendicular to the x-direction along the plane of the conductor. The z-direction is the direction perpendicular to the x-direction and y-directions. The thickness direction of each layer is an example of the z-direction.

[0022] 1 is a cross-sectional view of a non-reciprocal circuit device 100 according to a first embodiment. The non-reciprocal circuit device 100 includes, for example, a conductor 10, a first loss layer 21, a second loss layer 22, a first magnet 31, a second magnet 32, a first grounded body 41, and a second grounded body 42. The non-reciprocal circuit device 100 functions as, for example, an isolator.

[0023] Fig. 2 is a plan view of the conductor 10 and the first loss layer 21 of the nonreciprocal circuit element 100 according to the first embodiment. Fig. 1 is a cross section taken along line A-A in Fig. 2. Fig. 3 is a plan view of the conductor 10 of the nonreciprocal circuit element 100 according to the first embodiment. Fig. 4 is a plan view of the first loss layer 21 of the nonreciprocal circuit element 100 according to the first embodiment.

[0024] The conductor 10 has a first terminal T1 and a second terminal T2, which are connected to external terminals.

[0025] The conductor 10 transmits a high-frequency signal. The conductor 10 transmits the high-frequency signal non-reciprocally between the first terminal T1 and the second terminal T2. "Transmitting a high-frequency signal non-reciprocally" means that the propagation efficiency of the signal differs depending on the direction. For example, if the signal propagates with low loss in the forward direction but hardly propagates in the reverse direction, this corresponds to "transmitting a high-frequency signal non-reciprocally." The propagation direction of the high-frequency signal in the conductor 10 is controlled by a first loss layer 21 and a second loss layer 22, which will be described later.

[0026] A high-frequency signal input from the first terminal T1 is transmitted to the second terminal T2 with low loss. Most of the high-frequency signal input from the second terminal T2 is absorbed. In other words, almost no high-frequency signal is transmitted from the second terminal T2 to the first terminal T1. That is, the high-frequency signal is transmitted with low loss from the first terminal T1 to the second terminal T2, but almost no high-frequency signal is transmitted from the second terminal T2 to the first terminal T1.

[0027] The conductor 10 may be made of any material as long as it can transmit high-frequency signals efficiently. The conductor 10 may be made of, for example, aluminum, copper, silver, gold, stainless steel, etc. The conductor 10 may also be a non-conductor or a conductor with a high resistance (e.g., phosphor bronze) plated with aluminum, copper, silver, gold, stainless steel, etc.

[0028] The conductor 10 has a first region 11 and a second region 12. The conductor 10 may have regions other than the first region 11 and the second region 12. The first region 11 is a region that overlaps with the first magnetic body 25 in the z direction. The first region 11 extends between the first terminal T1 and the second terminal T2. The second region 12 is a region that overlaps with the first absorber 26 in the z direction. The boundary between the first region 11 and the second region 12 coincides with the boundary between the first magnetic body 25 and the first absorber 26, for example, when viewed from the z direction.

[0029] The conductor 10 has a first connection line S1 and a second connection line S2 on its outer periphery when viewed from the z direction. The first connection line S1 and the second connection line S2 are lines that connect the first terminal T1 and the second terminal T2, respectively. The first connection line S1 and the second connection line S2 join together to form the outer periphery of the conductor 10 when viewed from the z direction.

[0030] The first connection line S1 is one side of the first region 11. The first connection line S1 may be a straight line or a curved line. In the example shown in Fig. 2, the first connection line S1 is a straight line parallel to the straight line L1 connecting the first terminal T1 and the second terminal T2.

[0031] The second connection line S2 extends across the first region 11 and the second region 12. The second connection line S2 has, for example, a first side S21 and a second side S22 extending from the first region 11 to the second region 12, and a third side S23 which is one side of the second region 12. The first side S21, the second side S22, and the third side S23 may be straight or curved.

[0032] The conductor 10 has an unevenness 15 on its outer periphery when viewed from the z direction. The unevenness 15 is located on the second connection line S2. The unevenness 15 of the conductor 10 shown in FIG. 2 is located on the third side S23. The unevenness 15 is formed by convex portions protruding from the straight line L2 connecting the first end e1 and the second end e2. The sizes of the respective convex portions may be the same or different. The first end e1 is the end of the first side S21 on the second region 12 side and is the intersection of the first side S21 and the third side S23. The second end e2 is the end of the second side S22 on the second region 12 side and is the intersection of the second side S22 and the third side S23. The straight line L2 shown in FIG. 2 is parallel to the straight line L1. The straight line L2 does not have to be parallel to the straight line L1.

[0033] At least a portion of the unevenness 15 is located in the second region 12. A portion of the unevenness 15 may extend into the first region 11. The unevenness 15 shown in FIG. 2 is located in the second region 12. The unevenness 15 shown in FIG. 2 has a rectangular shape when viewed from the z direction, and is formed by multiple straight lines when viewed from the z direction. The unevenness 15 shown in FIG. 2 is symmetrical in the x direction with respect to the center line CL1. The center line CL1 is a line that passes through the center of the line L1 connecting the first terminal T1 and the second terminal T2 and is perpendicular to the line L1. Irregularities that are symmetrical with respect to the center line CL1 are easy to form, and a conductor 10 having irregularities that are symmetrical with respect to the center line CL1 is highly versatile.

[0034] The first loss layer 21 and the second loss layer 22 sandwich the conductor 10 in the z direction. The first loss layer 21 includes a first magnetic material 25 and a first absorber 26. The second loss layer 22 includes a second magnetic material 27 and a second absorber 28. The first loss layer 21 and the second loss layer 22 have substantially the same shape and are symmetrical with respect to the conductor 10. The first loss layer 21 is located between the conductor 10 and the first magnet 31. The second loss layer 22 is located between the conductor 10 and the second magnet 32.

[0035] The first magnetic body 25 and the first absorber 26 are, for example, located at different positions within the same xy plane. The second magnetic body 27 and the second absorber 28 are, for example, located at different positions within the same xy plane. The first magnetic body 25 and the second magnetic body 27 are located at positions overlapping with the first region 11 of the conductor 10 in the z direction. The first magnetic body 25 and the second magnetic body 27 sandwich the first region 11 in the z direction. The first absorber 26 and the second absorber 28 are located at positions overlapping with the second region 12 of the conductor 10 in the z direction. The first absorber 26 and the second absorber 28 sandwich the second region 12 in the z direction.

[0036] The first magnetic body 25 and the second magnetic body 27 may have any shape as long as they can cover the first region 11. The first absorber 26 and the second absorber 28 may have any shape as long as they can cover the second region 12. For example, as shown in Fig. 4 , the first magnetic body 25 and the first absorber 26 may both have a rectangular shape when viewed from the z direction.

[0037] A high-frequency signal passing through the conductor 10 propagates while being deflected to one side of the propagation direction due to the application of a DC magnetic field to the first magnetic body 25 and the second magnetic body 27. For example, a high-frequency signal input from the first terminal T1 is deflected to the vicinity of the first connection line S1 and propagates along the first connection line S1 to the second terminal T2. On the other hand, a high-frequency signal input to the second terminal T2 is deflected to the vicinity of the second connection line S2 and propagates along the second connection line S2 to the first terminal T1. At this time, the high-frequency signal input to the second terminal T2 is absorbed by the first absorber 26 and the second absorber 28 and is significantly attenuated.

[0038] The first magnetic body 25 and the second magnetic body 27 include a magnetic material. The first magnetic body 25 and the second magnetic body 27 may be a conductor or an insulator. The first magnetic body 25 and the second magnetic body 27 include, for example, a soft magnetic body. The first magnetic body 25 and the second magnetic body 27 may be, for example, a Co-based amorphous body, a ferrite, or an Fe ８５ Si ２ B ８ P ４ Cu, Fe ８６ AlB ８ P ４ Cu, Fe ７８ Si ９ B １３, yttrium iron garnet (YIG). YIG includes, for example, Y ３ Fe ２ (FeO ４ ) ３ , Y ３ Fe ５ O １２ is.

[0039] The first magnetic body 25 and the second magnetic body 27 may be a mixture of magnetic particles and resin. The magnetic particles may include, for example, iron, silicon steel (Fe—Si), permalloy (Ni—Fe), permendur (Fe—Co), sendust (Fe—Si—Al), electromagnetic stainless steel, amorphous iron-based alloys (Fe—B—C system, Fe—Co system), manganese zinc ferrite, nickel zinc ferrite, etc. The first magnetic body 25 and the second magnetic body 27 may be a mixture of ferrite particles and resin.

[0040] When dispersing a magnetic material in an insulating material (e.g., resin, rubber, paint, etc.), the volume ratio of the magnetic material is preferably 10% or more and 70% or less. If the volume ratio of the magnetic material is small, the electromagnetic wave absorption capacity will be low. If the volume ratio of the magnetic material is high, it will be difficult to disperse the magnetic material in the insulating material.

[0041] The first absorber 26 and the second absorber 28 include a material having a larger magnetic field loss rate than the first magnetic body 25 and the second magnetic body 27. The first absorber 26 and the second absorber 28 include, for example, any one selected from the group consisting of iron, BN, conductive carbon, SiC, and Ni-based ferrite.

[0042] When the first loss layer 21 and the second loss layer 22 are conductors, an insulating layer is provided between the first loss layer 21 and the conductor 10 and between the second loss layer 22 and the conductor 10. Any known insulating layer can be used.

[0043] The first magnet 31 and the second magnet 32 ​​sandwich the conductor 10, the first loss layer 21, and the second loss layer 22 in the z direction. The first magnet 31 and the conductor 10 sandwich the first loss layer 21 in the z direction. The second magnet 32 ​​and the conductor 10 sandwich the second loss layer 22 in the z direction. The first magnet 31 and the second magnet 32 ​​apply a DC magnetic field to the first magnetic body 25 and the second magnetic body 27.

[0044] 5 is a plan view of the first magnet 31 and the first grounding body 41 of the non-reciprocal circuit device 100 according to the first embodiment. The first magnet 31 and the second magnet 32 ​​are positioned so as to overlap the first magnetic body 25 and the second magnetic body 27 when viewed from the z direction. Parts of the first magnet 31 and the second magnet 32 ​​may overlap the first absorber 26 and the second absorber 28 when viewed from the z direction.

[0045] The first magnet 31 and the second magnet 32 ​​are, for example, hard magnetic materials. The first magnet 31 and the second magnet 32 ​​may be insulators or conductors. The first magnet 31 and the second magnet 32 ​​include, for example, any material selected from the group consisting of insulating ferrite magnets, conductive rare earth magnets, TbFeCo, GdFeCo, SmFeCo, [Co / Pt] multilayer films, and [Co / Pd] multilayer films. If the first magnet 31 and the second magnet 32 ​​are conductors, the first grounding body 41 and the second grounding body 42 may be omitted.

[0046] The first magnet 31 and the second magnet 32 ​​are an example of a magnetic field source. The magnetic field source is not limited to the first magnet 31 and the second magnet 32, as long as it can apply a DC magnetic field to the first magnetic body 25 and the second magnetic body 27.

[0047] The first grounded body 41 is sandwiched between the first magnet 31 and the first loss layer 21. The second grounded body 42 is sandwiched between the second magnet 32 ​​and the second loss layer 22. The first grounded body 41 or the second grounded body 42 is grounded to, for example, a reference potential. The reference potential is, for example, the ground. The first grounded body 41 and the second grounded body 42 may be any conductive material.

[0048] The non-reciprocal circuit device 100 according to this embodiment has excellent isolation characteristics due to the conductor 10 having the unevenness 15. The isolation characteristics are achieved when a high-frequency signal input to the second terminal T2 is absorbed by the first absorber 26 and the second absorber 28 as it propagates along the second connection line S2 to the first terminal T1. The presence of the unevenness 15 in the second connection line S2 increases the distance of the transmission path of the high-frequency signal from the second terminal T2 to the first terminal T1, thereby increasing the absorption efficiency of the high-frequency signal. High absorption efficiency of the high-frequency signal from the second terminal T2 to the first terminal T1 improves the isolation characteristics of the non-reciprocal circuit device 100.

[0049] The non-reciprocal circuit device 100 according to this embodiment can be applied to, for example, a quantum computer. Fig. 6 is a schematic diagram of the quantum computer according to this embodiment. The quantum computer 200 includes, for example, a quantum processor 201, non-reciprocal circuit devices 202 and 203, filters 204 and 205, and an amplifier 206.

[0050] The quantum processor 201 performs quantum computation. The non-reciprocal circuit elements 202 and 203 deliver a readout signal of a quantum bit from the quantum processor 201. The non-reciprocal circuit element 202 is a circulator. The non-reciprocal circuit element 203 is an isolator. The non-reciprocal circuit element 100 according to this embodiment can be applied to the non-reciprocal circuit element 203. The amplifier 206 amplifies the readout signal.

[0051] For example, superconducting quantum computers operate at cryogenic temperatures. Therefore, the quantum processor 201 and the non-reciprocal circuit elements 202 and 203 are also placed in positions exposed to a cryogenic environment. It is difficult to maintain a large volume of space in a cryogenic environment, and therefore, miniaturization of the non-reciprocal circuit elements 202 and 203 is required. The non-reciprocal circuit element 100 according to this embodiment is small in size and has excellent isolation characteristics, making it suitable for application to quantum computers.

[0052] Although an example of the first embodiment has been shown so far, the present invention is not limited to these embodiments, and various modifications are possible.

[0053] 7 is a plan view of a nonreciprocal circuit element 101 according to a first modified example. The nonreciprocal circuit element 101 according to the first modified example differs from the nonreciprocal circuit element 100 in the shape of the asperities 15A as viewed in the z direction. In FIG. 7, components similar to those of the nonreciprocal circuit element 100 are designated by the same reference numerals and will not be described.

[0054] The unevenness 15A is located on the second connection line S2. The unevenness 15A of the conductor 10A shown in FIG. 7 is located on the third side S23. The unevenness 15A is formed by convex portions protruding from the straight line L2 connecting the first end e1 and the second end e2. The unevenness 15A is located in the second region 12. The unevenness 15A has a triangular shape when viewed from the z direction, and is formed by multiple straight lines when viewed from the z direction. The unevenness 15A is symmetrical in the x direction with respect to the center line CL1.

[0055] The non-reciprocal circuit device 101 according to the first modification has the irregularities 15A on the second connection line S2, and therefore has the same effects as the non-reciprocal circuit device 100.

[0056] 8 is a plan view of a nonreciprocal circuit element 102 according to a second modification. The nonreciprocal circuit element 102 according to the second modification differs from the nonreciprocal circuit element 100 in the shape of the irregularities 15B as viewed in the z direction. In FIG. 8, components similar to those of the nonreciprocal circuit element 100 are designated by the same reference numerals and will not be described.

[0057] The unevenness 15B is located on the second connection line S2. The unevenness 15B of the conductor 10B shown in FIG. 8 is located on the third side S23. The unevenness 15B is formed by convex portions protruding from the straight line L2 connecting the first end e1 and the second end e2. The unevenness 15B is located in the second region 12. The unevenness 15B has at least a portion curved when viewed from the z direction. The convex portions forming the unevenness 15B have curves that are curved when viewed from the z direction. The unevenness 15B is symmetrical in the x direction with respect to the center line CL1.

[0058] The non-reciprocal circuit device 102 according to the second modification has the irregularities 15B on the second connection line S2, and therefore has the same effects as the non-reciprocal circuit device 100.

[0059] As shown in the first and second modifications, the isolation characteristics of the non-reciprocal circuit device are improved regardless of the shape of the projections and recesses when viewed from the z direction. This is because the length of the reverse propagation path of the high-frequency signal from the second terminal T2 to the first terminal T1 can be increased. Furthermore, when the projections are configured as straight lines, it is easier to increase the length of the second connection line S2, thereby further improving the isolation characteristics of the non-reciprocal circuit device. Furthermore, when the projections include curves, they are easier to process, facilitating the manufacture of the non-reciprocal circuit device.

[0060] 9 is a plan view of a nonreciprocal circuit element 103 according to a third modified example. The nonreciprocal circuit element 103 according to the third modified example differs from the nonreciprocal circuit element 100 in that the irregularities 15C are formed as concave portions. In FIG. 9, the same components as those in the nonreciprocal circuit element 100 are denoted by the same reference numerals, and description thereof will be omitted.

[0061] The unevenness 15C is located on the second connection line S2. The unevenness 15C of the conductor 10C shown in FIG. 9 is located on the third side S23. The unevenness 15C is formed by a recess recessed from the straight line L2 connecting the first end e1 and the second end e2. The unevenness 15C is located in the second region 12. The unevenness 15C has a rectangular shape when viewed from the z direction, and is formed by multiple straight lines when viewed from the z direction. The unevenness 15C is symmetrical in the x direction with respect to the center line CL1.

[0062] The non-reciprocal circuit device 103 according to the third modification has the second connection line S2 having the irregularities 15C, and therefore has the same effects as the non-reciprocal circuit device 100.

[0063] 10 is a plan view of a nonreciprocal circuit element 104 according to a fourth modification. The nonreciprocal circuit element 104 according to the fourth modification differs from the nonreciprocal circuit element 100 in that the irregularities 15D are made up of concave and convex portions. In FIG. 10, the same components as those in the nonreciprocal circuit element 100 are denoted by the same reference numerals, and description thereof will be omitted.

[0064] The unevenness 15D is located on the second connection line S2. The unevenness 15D of the conductor 10D shown in FIG. 10 is located on the third side S23. The unevenness 15D is formed by convex portions protruding from the straight line L2 and concave portions recessed from the straight line L2. The unevenness 15D is located in the second region 12. The unevenness 15D has a rectangular shape when viewed from the z direction, and is formed by multiple straight lines when viewed from the z direction. The unevenness 15D is symmetrical in the x direction with respect to the center line CL1.

[0065] The nonreciprocal circuit element 104 according to the fourth modification has the unevenness 15D on the second connecting line S2, and therefore has the same effect as the nonreciprocal circuit element 100. As shown in the third and fourth modifications, regardless of the combination of convex and concave portions in the unevenness, the length of the transmission path for the high-frequency signal in the reverse direction can be increased, and the isolation characteristics of the nonreciprocal circuit element are improved.

[0066] 11 is a plan view of a nonreciprocal circuit element 105 according to a fifth modified example. The nonreciprocal circuit element 105 according to the fifth modified example differs from the nonreciprocal circuit element 100 in the position where the irregularities 15E are formed. In FIG. 11, the same components as those in the nonreciprocal circuit element 100 are denoted by the same reference numerals, and description thereof will be omitted.

[0067] The unevenness 15E is located on the second connection line S2. The unevenness 15E of the conductor 10E shown in FIG. 2 is located on the first side S21 and the second side S22. The unevenness 15E may be located on both the first side S21 and the second side S22, or on only one of them. The unevenness 15E is formed by convex portions protruding from the reference lines BL1 and BL2. The reference line BL1 is a straight line connecting the first end and the second end of the first side S21. The reference line BL2 is a straight line connecting the first end and the second end of the second side S22. Neither the reference line BL1 nor the reference line BL2 is parallel to the line L2. The unevenness 15E is located in the second region 12. The unevenness 15E is symmetrical in the x-direction with respect to the center line CL1.

[0068] When the first absorber 26 is rectangular, if the first side S21 or the second side S22 has irregularities, it is easy to increase the size of the irregularities. This is because the protruding direction of the recesses approaches the diagonal direction of the rectangular first absorber 26. The larger the size of the irregularities, the longer the length of the transmission path for the high-frequency signal in the reverse direction can be, and the better the isolation characteristics of the non-reciprocal circuit device.

[0069] The nonreciprocal circuit element 105 according to the fifth modification has the asperity 15E on the second connecting line S2, and therefore has the same effect as the nonreciprocal circuit element 100. As shown in the fifth modification, if the asperity is located anywhere on the second connecting line S2, it is possible to increase the distance of the transmission path from the second terminal T2 to the first terminal T1, and to improve the isolation characteristics of the nonreciprocal circuit element.

[0070] 12 is a plan view of a nonreciprocal circuit device 106 according to a sixth modified example. The nonreciprocal circuit device 106 according to the sixth modified example differs from the nonreciprocal circuit device 100 in the shape of the irregularities 15F. In FIG. 12, the same components as those in the nonreciprocal circuit device 100 are denoted by the same reference numerals, and description thereof will be omitted.

[0071] The unevenness 15F is located on the second connection line S2. The unevenness 15F of the conductor 10F shown in FIG. 12 is located on the third side S23. The unevenness 15F is formed by a convex portion protruding from the straight line L2 and a concave portion recessed from the straight line L2. A portion of the unevenness 15F is located in the second region 12, and the remaining portion is located in the first region 11. In other words, a portion of the concave portion of the unevenness 15F extends into the first region 11. The unevenness 15F has a rectangular shape when viewed from the z direction, and is formed by multiple straight lines when viewed from the z direction. The unevenness 15F is symmetrical in the x direction with respect to the center line CL1.

[0072] The non-reciprocal circuit device 106 according to the sixth modification has the irregularities 15F on the second connection line S2, and therefore has the same effects as the non-reciprocal circuit device 100.

[0073] 13 is a plan view of a nonreciprocal circuit element 107 according to a seventh modification. The nonreciprocal circuit element 107 according to the seventh modification differs from the nonreciprocal circuit element 100 in the shape of the irregularities 15G. In FIG. 13, the same components as those in the nonreciprocal circuit element 100 are denoted by the same reference numerals, and description thereof will be omitted.

[0074] 13 includes an uneven portion 15G. The third side S23 is formed by a curved line when viewed from the z direction.

[0075] The unevenness 15G is formed by convex portions protruding from the straight line L2. Part of the unevenness 15G is in the second region 12, and the remaining part is in the first region 11. In other words, part of the unevenness 15G hangs over the first region 11. Part of the convex portions of the unevenness 15G are located in the second region 12. The unevenness 15G is curved when viewed from the z direction, and is composed of curved lines. The unevenness 15G is symmetrical in the x direction with respect to the center line CL1.

[0076] The non-reciprocal circuit device 107 according to the seventh modification has the unevenness 15G on the second connection line S2, and therefore has the same effects as the non-reciprocal circuit device 100.

[0077] Furthermore, as shown in the sixth and seventh modifications, even if part of the asperities reaches the first region 11, the distance of the transmission path of the high-frequency signal from the second terminal T2 to the first terminal T1 can be increased, thereby improving the isolation characteristics of the non-reciprocal circuit element. Furthermore, by increasing the degree of asperity as the position of the asperities approaches the first region 11, the distance of the transmission path of the high-frequency signal from the second terminal T2 to the first terminal T1 can be further increased.

[0078] 14 is a plan view of a nonreciprocal circuit device 108 according to an eighth modification. The nonreciprocal circuit device 108 according to the eighth modification differs from the nonreciprocal circuit device 100 in the position of the asperities 15H. In FIG. 14, components similar to those of the nonreciprocal circuit device 100 are designated by similar reference numerals, and description thereof will be omitted.

[0079] The unevenness 15H is located on the second connection line S2. The unevenness 15H of the conductor 10H shown in Fig. 14 is formed by a convex portion protruding from the straight line L2. The unevenness 15H is located in the second region 12. The unevenness 15H has a rectangular shape when viewed from the z direction, and is formed by a plurality of straight lines when viewed from the z direction.

[0080] The irregularities 15H are located closer to the second terminal T2 than the center line CL1 and are asymmetric in the x-direction with respect to the center line CL1. The position of the irregularities 15H is not important as long as they are asymmetric in the x-direction with respect to the center line CL1. For example, the irregularities 15H may be located closer to the first terminal T1 than the center line CL1, or may be located on both the first terminal T1 and second terminal T2 sides with respect to the center line CL1. The strength of the high-frequency signal input from the second terminal T2 becomes weaker as it approaches the first terminal T1. Therefore, having more irregularities on the second terminal T2 side, where the high-frequency signal strength is stronger, further improves the isolation characteristics.

[0081] The non-reciprocal circuit device 108 according to the eighth modification has the unevenness 15H on the second connection line S2, and therefore has the same effects as the non-reciprocal circuit device 100.

[0082] Up to this point, several examples of the structure of the nonreciprocal circuit device have been shown, including modified examples. The nonreciprocal circuit device according to this embodiment is not limited to these examples, as long as it can extend the transmission distance of the second connection line S2. Furthermore, the nonreciprocal circuit device according to this embodiment may combine the characteristic structures of the respective modified examples.

[0083] Example 1 In Example 1, a non-reciprocal circuit element 100 having the same configuration as that shown in FIG. 2 was fabricated. The conductor 10 of Example 1 has rectangular irregularities formed on the third side S23 of the second connection line S2. The irregularities are symmetrical in the x direction with respect to the center line CL1. The irregularities are located in the second region 12. The insertion loss characteristics, reflection loss characteristics, and isolation characteristics of the non-reciprocal circuit element of Example 1 versus frequency were determined by simulation.

[0084] Comparative Example 1 The non-reciprocal circuit device of Comparative Example 1 is the same as that of Example 1 except that the concaves and convexes are removed. That is, the non-reciprocal circuit device 100 has the same configuration as that of Fig. 2 but without the concaves and convexes 15, and the third side S23 is a straight line extending along the line L2. The insertion loss characteristics, reflection loss characteristics, and isolation characteristics of the non-reciprocal circuit device of Comparative Example 1 versus frequency were determined by simulation.

[0085] Fig. 15 shows the measurement results of the insertion loss characteristics of the non-reciprocal circuit devices according to Example 1 and Comparative Example 1. Fig. 16 shows the measurement results of the reflection loss characteristics of the non-reciprocal circuit devices according to Example 1 and Comparative Example 1. Fig. 17 shows the measurement results of the isolation characteristics of the non-reciprocal circuit devices according to Example 1 and Comparative Example 1. The horizontal axes in Figs. 15 to 17 represent the frequency of the high-frequency signal input to the terminal.

[0086] 17, the nonreciprocal circuit device of Example 1 has superior isolation characteristics compared to the nonreciprocal circuit device of Comparative Example 1. This is thought to be because the nonreciprocal circuit device of Example 1 has unevenness, which lengthens the propagation path of the high-frequency signal in the reverse direction from the second terminal T2 toward the first terminal, and most of the high-frequency signal is absorbed by the absorber.

[0087] 15 and 16, there was no significant difference in insertion loss and reflection loss between Example 1 and Comparative Example 1. In other words, the unevenness of the conductor had almost no effect on the insertion loss and reflection loss.

[0088] 10, 10A, 10B, 10C, 10D, 10E, 10F, 10G, 10H...conductor 11...first region 12...second region 21...first loss layer 22...second loss layer 25...first magnetic body 26...first absorber 27...second magnetic body 28...second absorber 31...first magnet 32...second magnet 41...first grounded body 42...second grounded body 100, 101, 102, 103, 104, 105, 106, 107, 108, 202, 203...non-reciprocal circuit element 200...quantum computer 201...quantum processor 204, 205...filter 206...amplifier e1...first terminal e2...second terminal L1, L2...straight line S1...first connecting line S2...Second connecting line S21...First side S22...Second side S23...Third side T1...First terminal T2...Second terminal

Claims

1. A non-reciprocal circuit element comprising a conductor, a magnetic material, and an absorber, the conductor having a first terminal and a second terminal, the conductor having a first region that overlaps with the magnetic material when viewed in the thickness direction and spans the first terminal and the second terminal, and a second region that overlaps with the absorber when viewed in the thickness direction, the conductor having irregularities on its outer periphery when viewed in the thickness direction, and at least a portion of the irregularities are located in the second region.

2. The non-reciprocal circuit element according to claim 1, wherein the projections and recesses are formed by a plurality of straight lines when viewed in the thickness direction.

3. The non-reciprocal circuit element according to claim 1, wherein the projections and recesses have at least a portion that is curved when viewed in the thickness direction.

4. The non-reciprocal circuit element according to claim 1, wherein the reference line of the projections and recesses is not parallel to a straight line connecting the first terminal and the second terminal.

5. The non-reciprocal circuit element according to claim 1, wherein at least a portion of said projections and recesses is located in said first region.

6. The non-reciprocal circuit element according to claim 1, wherein the projections and recesses are symmetrical with respect to a center line that passes through the center of a straight line connecting the first terminal and the second terminal and is perpendicular to the straight line.

7. A non-reciprocal circuit element according to claim 1, wherein the projections and recesses are asymmetric with respect to a center line that passes through the center of a straight line connecting the first terminal and the second terminal and is perpendicular to the straight line.

8. The non-reciprocal circuit element according to claim 1, further comprising a magnetic field source capable of applying a DC magnetic field to said magnetic body.

9. A non-reciprocal circuit element comprising a conductor, a magnetic material, and an absorber, wherein the magnetic material and the absorber are each positioned to overlap the conductor in the thickness direction, the conductor has irregularities on at least a portion of its outer periphery, and at least a portion of the irregularities are positioned to overlap the absorber when viewed from the thickness direction.

10. A quantum computer comprising the non-reciprocal circuit element according to claim 1.

Images