CN204497356U - A kind of 3D microwave cavity containing direct current lead structure - Google Patents

Abstract

The utility model discloses a 3D microwave resonant cavity, which comprises a cavity body, a circuit board, an input port and an output port. The port penetrates the housing from the upper part of the cavity (1) and communicates with the cavity, and the cavity has a slot from one side along the extending direction of the cavity toward the cavity; the circuit board includes an outer connection part (2a) and an inner For the insertion part, the width of the outer part is wider, and the width of the inner part is narrower and elongated, and the inner part is inserted into the cavity through the slot. And the interpolation part includes a metal lead extending along its insertion direction, a qubit device installation position at the end of the insertion part, and an equipotential connection line connecting the metal lead and the qubit device installation position. The utility model can achieve better coupling effect, and can realize precise control of qubits.

Description

A 3D Microwave Resonator with a DC Lead Structure

technical field

The utility model relates to a microwave circuit device, in particular to a 3D microwave resonant cavity including a direct current lead structure.

Background technique

The semiconductor quantum chip is based on the traditional semiconductor industry, making full use of quantum mechanical effects to realize the core components of high-efficiency parallel quantum computing. Qubits, which can be quantum dots or devices such as superconducting quantum interferometers, are the basic units on quantum chips that can store and manipulate quantum information. However, to complete the quantum computing process, it is also necessary to realize the coupling and data exchange between qubits, as well as the detection and readout of quantum information. Ordinary electronic circuits cannot transmit quantum information, so we need some special electronic components to achieve this function for us. Microwave resonators can excite and transmit microwave photons that can carry quantum information to achieve this function, and 3D microwave resonators are high-efficiency microwave resonators. We hope to obtain a kind that can achieve good coupling with the qubit, has a suitable quality factor (ie, Q value), and at the same time can add a DC lead structure to achieve precise control of the qubit, and can also be used as an effective detector. , to read out the information of the qubit.

Utility model content

(1) Technical problems to be solved

Aiming at the above requirements, the utility model designs a 3D resonant cavity device with a direct current lead structure, which can meet the requirements of qubit detection and mutual communication.

(2) Technical solutions

In order to solve the above-mentioned technical problems, the utility model proposes a 3D microwave resonant cavity, which includes a cavity, a circuit board, an input port and an output port, wherein the cavity is a cuboid, including a shell and a cavity inside the shell. Cavity, the extending direction of the cavity is consistent with the length direction of the cavity; the input port and the output port penetrate the casing from the upper part of the cavity to communicate with the cavity, and the cavity is along one side of the cavity A slot is opened toward the cavity along the extending direction of the cavity; the circuit board includes an external part and an internal part, the external part has a wide width, and the internal part has a narrow width and is elongated, so that The circuit board as a whole resembles a "T" shape; the insertion part can be inserted into the cavity of the cavity through the slot of the cavity; and the insertion part includes metal leads extending along the insertion direction, located in the insertion part The qubit device installation position at the end, and the equipotential connection line connecting the metal lead and the qubit device installation position.

According to a specific embodiment of the present invention, the cavity is composed of front and rear parts, the two parts are symmetrical in structure and can be combined through a mechanical structure.

According to a specific embodiment of the present invention, the access positions of the input port and the output port are symmetrically distributed on the upper surface of the cavity.

According to a specific implementation manner of the present utility model, when the circuit board insertion part is completely inserted into the cavity, the installation position of the qubit device is just located in the center of the cavity of the cavity.

According to a specific embodiment of the present utility model, the outside of the cavity also has a fixing part, which is located on one side of the circuit board and forms an integral body with the cavity. When all the insertion parts of the circuit board are inserted into the cavity , the external part of the circuit board can be fixed on the fixing part.

According to a specific embodiment of the present invention, the insertion direction of the insertion part of the circuit board 2 is perpendicular to the insertion direction of the input port and the output port.

According to a specific embodiment of the utility model, the shell of the cavity is made of pure aluminum.

According to a specific embodiment of the present utility model, the cavity of the cavity is located at the center of the housing.

According to a specific embodiment of the present utility model, the circuit board is a PCB board.

(3) Beneficial effects

Adopting the technical solution used in the utility model can fully meet the application requirements of the quantum chip, specifically manifested in:

1. The input and output ports of the utility model are located on the same side of the outer wall of the 3D cavity, and are symmetrically distributed, so that the electric field distribution inside the 3D cavity has a high degree of symmetry;

2. The utility model has a slot on one side of the cavity of the 3D microwave resonator. The position has been verified by multiple simulations. The electromagnetic wave will not leak from the gap to cause loss, and will not introduce external noise through the gap. The circuit board After being inserted into the 3D cavity through the gap, it will not cause significant attenuation of the electric field strength;

3. This utility model uses a circuit board engraved with a special metal lead structure. After the circuit board is inserted into the 3D microwave resonator, the direction of the metal lead will not cause a significant attenuation of the electric field intensity. On the contrary, it can also be enhanced locally Electric field strength to achieve better coupling effect;

4. The utility model uses the metal leads on the circuit board and the equipotential connection line to connect the electrodes on the qubit device to the outside world and connect to the measuring device, thereby realizing the precise regulation of the qubit.

Description of drawings

Fig. 1 is a schematic structural view of a 3D microwave resonator according to an embodiment of the present invention;

Fig. 2 is a schematic structural view of the cavity adopted in the above-mentioned embodiment of the utility model;

Fig. 3 is the structural representation of the circuit board that adopts in the above-mentioned embodiment of the utility model;

Fig. 4 is a schematic diagram when the circuit board of the above-mentioned embodiment of the present invention is fully inserted into the cavity;

Fig. 5 is a schematic diagram of an example of using the 3D microwave resonant cavity of the embodiment of the present invention to detect gallium arsenide double quantum dots.

Detailed ways

The utility model proposes a 3D microwave resonant cavity, which includes a cavity body, a circuit board, an input port and an output port. The cavity body is a cuboid, including a shell and a cavity opened inside the shell. The cavity is generally located in the center of the shell. , and the extension direction is consistent with the length direction of the cavity. The input port and the output port penetrate the housing from the upper portion of the cavity to communicate with the cavity. A slot is opened to the cavity from one side of the cavity along the extending direction of the cavity.

The circuit board includes an external part and an internal part. The external part has a wider width, and the internal part has a narrower width and is in the shape of a long strip, so that the circuit board as a whole resembles a "T" shape. The insertion portion is insertable into the cavity of the cavity via the slot of the cavity. The interpolation part of the circuit board is engraved with metal leads extending along its insertion direction, qubit device installation positions at the end of the insertion part, and equipotential bonding wires (bonding wires) connecting the metal leads and the qubit device installation positions. The metal lead wire and the equipotential connection wire together constitute the DC lead wire structure of the utility model.

The cavity body of the utility model can adopt the existing 3D microwave resonant cavity, and its shell is usually made of pure aluminum. The access positions of the input port and the output port are usually distributed symmetrically on the upper surface of the cavity, and their purpose is to provide the input microwave signal for the 3D microwave resonator and measure the intensity of the output signal respectively. The purpose of the cavity of the aluminum casing is to form a superconducting ideal boundary at extremely low temperature to reduce the loss caused by internal microwave reflection through the boundary. The cavity with a specific size inside can construct a specific standing wave mode, and the frequency of each standing wave mode is the resonant frequency of the microwave in the cavity. Aluminum has a high superconducting critical temperature (1.198K). It exhibits superconducting characteristics at the working temperature of the qubit and at low temperature, making the boundary of the 3D cavity an ideal boundary, thereby greatly reducing the energy loss caused by dissipation. At the same time, because the thermal noise is very small at extremely low temperatures, this resonant cavity can maintain a state where there are only a few or even a single photon in the cavity, thereby accurately transmitting the required quantum information.

The cavity can be composed of front and rear parts, the two parts are symmetrical in structure and can be combined through a mechanical structure. Therefore, after the front and rear parts are separated, that is, after the cavity is opened, a qubit device can be placed in the very center of the cavity. The extending direction of the input port and the output port is generally parallel to the front and rear surfaces of the cavity. When the 3D cavity is closed and works at an extremely low temperature, the qubit device is in the very center, and the microwave intensity felt is the highest, so that the maximum coupling can be achieved. The qubit device is installed on the qubit device installation position of the circuit board, and when the interpolation part of the circuit board fully extends into the cavity, the qubit device is placed in the center of the cavity of the cavity.

The qubit device is attached to the qubit device installation position on the circuit board, and the electrodes on the qubit device are connected to the corresponding metal leads on the circuit board through equipotential bonding wires. In order to make the qubit device located in the center of the cavity of the cavity during operation, the length of the interpolation part of the circuit board and the position of the slot of the cavity are set in the utility model, so that when the interpolation part is fully inserted When the cavity is formed, the mounting position of the qubit device is exactly located in the center of the cavity of the cavity.

In order to make the direction of the lead wire not affect the distribution of the electromagnetic field inside the cavity, the insertion direction of the circuit board's interpolation part is perpendicular to the insertion direction of the input port and the output port.

According to a preferred embodiment of the present invention, the outside of the cavity can also have a fixing part, which is located on one side of the circuit board and forms an integral body with the cavity. When all the inserting parts of the circuit board are inserted into the cavity, The external part of the circuit board can be fixed on the fixing part of the cavity.

In the utility model, the purpose of the metal lead structure on the circuit board is to connect the electrodes on the qubit device attached to the end of the circuit board, so as to realize the precise control of the qubit. The distribution direction of the metal leads is simulated in detail. They are arranged along the insertion direction. Not only will the metal leads not weaken the electric field strength in the cavity, but they will amplify the electric field strength locally to achieve a better coupling effect. The metal lead structure extends to the outside of the circuit board to connect with external measurement equipment.

In order to make the purpose, technical solutions and advantages of the utility model clearer, the utility model will be further described in detail below in combination with specific embodiments and with reference to the accompanying drawings.

Fig. 1 is a schematic structural diagram of a 3D microwave resonator according to an embodiment of the present invention. Referring to accompanying drawing 1 , the 3D microwave resonant cavity of the present invention includes a cavity body 1 , a circuit board 2 , an input port 3 and an output port 4 . The input port 3 and the output port 4 are located above the cavity, and the circuit board 2 protrudes into the cavity from one side of the cavity 1 . It should be noted that the cavity 1 has a thickness in a direction perpendicular to the paper, and FIG. 1 is a front view, so it is not shown. The thickness of the circuit board 2 is relatively small, and it is in the shape of a sheet. Moreover, the cavity 1 is composed of two parts, the front and the back, and the two parts are symmetrical in structure and can be combined through a mechanical structure. However, what is shown in FIG. 1 is a schematic diagram after removing the first half thereof.

Fig. 2 is a schematic structural view of the cavity adopted in the above-mentioned embodiment of the present utility model. As shown in FIG. 2 , the cavity 1 is a cuboid, including a casing 11 and a cavity 12 opened inside the casing, and the extending direction of the cavity is consistent with the length direction of the cavity. The input port 3 and the output port 4 penetrate the housing 11 from the upper part of the cavity 1 to communicate with the cavity 12 . The cavity body 1 has a slot 13 opened into the cavity from one side thereof along the extending direction of the cavity. The input port 3 and the output port 4 are vertically inserted into the cavity 1 from the upper part of the cavity 1 . The circuit board 2 protrudes from one side of the cavity 1 with the slot 13 through the slot 13 , and the plane of the circuit board 2 is parallel to the front and rear planes of the cavity 1 . 13a in the figure is the slit of the external opening of the slit.

Fig. 3 is a structural schematic diagram of the circuit board used in the above-mentioned embodiment of the present utility model. As shown in Figure 3, the circuit board 2 is a PCB board, including an external part 2a and an interpolation part 2b. The width of the external part 2a is relatively wide, and the width of the interpolation part 2b is narrow and strip-shaped, so that the circuit board as a whole is similar to A "T" shape. The inserting portion 2b can be inserted into the cavity of the cavity 1 via the slot 13 of the cavity. The insertion part 2b of the circuit board is engraved with metal leads 21 extending along its insertion direction, and the position at the end of the insertion part 2b is a qubit device installation position 2d, which is used for installing the qubit installation device. In the equipotential bonding line area 2c at the position on the circuit board between the qubit device installation position 2d and the metal wire junction 21, equipotential bonding wires (bonding wires, not shown in the figure) are distributed therein. The metal lead wire 21 and the equipotential connection wire together constitute the DC lead wire structure of the present invention. Since the equipotential bonding line is extremely short and thin, it is not drawn in Figure 3.

The external part 2a of the circuit board 2 is fixed on the shell 11 of the cavity 1 (a fixed part extends from the shell to the circuit board 2, not shown in the figure), and is responsible for leading out the DC leads in the cavity 1. At the left end of the external part 2a, there is a common 8-pin hole socket base structure. After the socket is welded, the lead wire of the measuring device can be plugged in to connect the DC lead wire, so as to finally control the qubit device.

As shown in FIG. 1 , the direction of the metal lead 21 is perpendicular to the direction in which the input port 3 and the output port 4 extend. It should also be noted that the number of metal leads 21 is not fixed, and the number of leads can be 8 to 16 due to different requirements and size constraints. Equipotential bonding lines can use existing wire bonding equipment.

The qubit equipment involved in the utility model can adopt existing equipment, but since the purpose of the utility model is to precisely control various qubit equipment, the qubit equipment constitutes a subsidiary of the utility model. Accessories.

Fig. 4 is a schematic diagram of the above embodiment of the present invention when the circuit board is fully inserted into the cavity. After a lot of simulations by the designer of the present application, in the normal working mode of the 3D microwave resonator, the center of the cavity in the cavity is the strongest microwave. Therefore, in order to achieve maximum coupling, we placed the qubit device in the very center of the cavity. To achieve this, the qubit device needs to be installed on the installation position 2d, and the length of the insertion part 2b of the circuit board just reaches the exact center of the cavity 12.

Fig. 5 is a schematic diagram of an example of using the 3D microwave resonant cavity of the embodiment of the present invention to detect gallium arsenide double quantum dots. The microwave signal with extremely low amplitude starts from the output port 5 of the network analyzer, passes through the input port of the 3D microwave resonant cavity included in the utility model, and after reaching resonance in the 3D microwave resonant cavity, passes through the output port 4 of the 3D cavity, and then passes through the output port 4 of the 3D cavity. Returns the input port of network analyzer 5. The network analyzer 5 can give information such as the amplitude, phase, and resonant peak Q value of the S parameters of the entire circuit. The qubit device used in this embodiment, that is, gallium arsenide double quantum dots 8, via the equipotential connection line of the circuit board 2 and the metal lead 21, the gallium arsenide double quantum dots 8 and a series of DC biasing The lock-in amplifier 6 is connected. The function of the lock-in amplifier 6 is to bias each output port with a constant DC voltage, so that the precise regulation of the gallium arsenide double quantum dot 8 is realized by means of the DC lead structure of the present invention. Under a suitable DC bias, the microwave photons in the 3D microwave resonator and the electrons in the gallium arsenide double quantum dot 8 are in a coupled state, and can exchange information with each other, thus affecting the resonance characteristics of the microwave photons, which is finally reflected in the measured on the S parameter. The network analyzer 5 and the lock-in amplifier 6 used in this embodiment are all controlled by a computer 7 to achieve the purpose of collecting and storing a large amount of data.

As mentioned above, in the utility model, microwave photons are transmitted in the cuboid space wrapped by the aluminum shell to form a specific standing wave mode. This structure has two advantages: first, the standing wave mode in the cuboid cavity can be easily obtained by solving the boundary conditions of electromagnetic wave transmission, and the error between the actual object and the theoretical simulation is smaller, so the controllability is higher; In the 3D microwave resonator, the distribution of the electric field has a high degree of symmetry, so it is very easy to obtain the position with the highest electric field intensity, thereby ensuring the strongest coupling between the internal qubit device and the microwave photon. During the use of the utility model, the lowest-order TE101 standing wave mode is generally used, because there is only one place with the largest electric field intensity in this mode, that is, the center of the 3D microwave resonant cavity, which greatly simplifies other aspects related to the utility model. part of the design.

And, in the present invention, the qubit device is adhered to the end of the circuit board, protruding precisely to the very center of the 3D cavity. The board plane passes through the very center of the 3D cavity. The position of the gap has been simulated in detail, and the internal electromagnetic waves will not leak from the gap, and at the same time, it will not introduce excessive noise sources.

The specific embodiments described above have further described the purpose, technical solutions and beneficial effects of the utility model in detail. It should be understood that the above descriptions are only specific embodiments of the utility model and are not intended to limit the utility model. For new models, any modifications, equivalent replacements, improvements, etc. made within the spirit and principles of the present utility model shall be included within the protection scope of the present utility model.

Claims (9)

1. A 3D microwave resonant cavity, comprising a cavity (1), a circuit board (2), an input port (3) and an output port (4), wherein, The cavity is a cuboid, comprising a casing (11) and a cavity (12) opened inside the casing, and the extension direction of the cavity (12) is consistent with the length direction of the cavity (1); The input port (3) and the output port (4) penetrate the housing (11) from the upper part of the cavity (1) to communicate with the cavity (12), and the cavity extends along the cavity from one side thereof. A slot (13) is opened toward the cavity in the extending direction of the cavity; The circuit board (2) includes an external part (2a) and an internal part (2b), the external part has a wider width, and the internal part has a narrower width and is elongated, so that the circuit board as a whole resembles a "T" shape; the insertion part can be inserted into the cavity of the cavity through the slot (13) of the cavity; and the insertion part includes a metal lead (21) extending along its insertion direction, a A qubit device installation position (2d), and an equipotential connection line connecting the metal lead and the qubit device installation position. 2. The 3D microwave resonant cavity according to claim 1, characterized in that, the cavity (1) is composed of two parts, front and rear, and the two parts are symmetrical in structure and can be combined through a mechanical structure. 3. The 3D microwave resonant cavity according to claim 1, characterized in that, the access positions of the input port (3) and the output port (4) are symmetrically distributed on the upper surface of the cavity (1). 4. The 3D microwave resonant cavity according to claim 1, characterized in that, when the circuit board interpolation part (2b) is fully inserted into the cavity, the installation position of the qubit device is just in the cavity The center of the cavity (12). 5. 3D microwave resonant cavity as claimed in claim 1, is characterized in that, the outside of described cavity (1) also has a fixed portion, and this fixed portion is positioned at the side of circuit board (2) and is connected with cavity ( 1) Forming a whole body, when all the inserting parts (2b) of the circuit board (2) are inserted into the cavity (1), the external part of the circuit board can be fixed on the fixing part. 6. The 3D microwave resonant cavity according to claim 1, characterized in that, the insertion direction of the interpolation part (2b) of the circuit board 2 is the same as the extension direction of the input port (3) and the output port (4). The entry direction is vertical. 7. The 3D microwave resonant cavity according to claim 1, characterized in that, the casing (11) of the cavity is made of pure aluminum. 8. The 3D microwave resonant cavity according to claim 1, characterized in that, the cavity (12) of the cavity (1) is located at the center of the housing (11). 9. The 3D microwave resonant cavity according to claim 1, characterized in that, the circuit board (2) is a PCB board.