Terahertz adjustable power distribution synthesis structure optimization method and system
By designing a terahertz T-junction power distribution synthetic structure based on graphene, the electrical parameters and absorption matching load of graphene are used to achieve high isolation and miniaturization integration of the terahertz power distribution structure, solving the problems of low isolation and high loss in traditional structures.
Patent Information
- Application Number
- CN202411813012.6
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2024-12-11
- Publication Date
- 2025-04-25
AI Technical Summary
The traditional terahertz planar metal structure cannot be integrated into miniaturized systems, and the traditional waveguide T-type junction divider has low port isolation, which limits its application.
By designing the terahertz T-junction power distribution synthesis structure, the dispersion curve is calculated using the chemical potential and relaxation time simulation of graphene, the electrical parameters of graphene are determined, and the absorption matching load is constructed, and the grooved processing is carried out to obtain the terahertz adjustable power distribution synthesis structure based on graphene, and the isolation is optimized in real time.
The port isolation of the terahertz power distribution structure is improved, the integration problem of traditional structures in miniaturized systems is solved, and the insertion loss and return loss are reduced.
Smart Images
Figure CN119886024A_ABST
Abstract
Description
Technical Field
[0001] The present application relates to the technical field of terahertz power dividers, and in particular to a method and system for optimizing a terahertz adjustable power distribution synthesis structure. Background Art
[0002] In recent years, with the gradual maturity of semiconductor transistors and micro-assembly technology, terahertz solid-state devices have been rapidly developed and applied in fields such as radar communications. High-power transmitters are important components in terahertz information perception, transmission and detection solid-state devices. Inevitably, power synthesis technology is naturally used to solve the difficulties of terahertz monolithic integrated circuits under high power requirements. The E-plane waveguide T-junction has the advantages of low loss and easy integration with terahertz monolithic integrated circuits. It is also the most commonly used structure in power distribution applications. Usually, each terahertz amplifier chip requires a waveguide port in the T-junction structure for power distribution or synthesis. However, the traditional waveguide T-junction power divider has a low port isolation. Ideally, the two ports have a maximum isolation of only 6dB, which limits its further application. In order to improve the isolation at the output port of the power divider, it is inevitable to introduce an isolation port, such as a resistor and an absorbing material. However, these introduced materials cannot be well integrated into the power divider, which will introduce additional insertion loss and return loss. In addition, traditional terahertz planar metal structures cannot be further integrated into miniaturized systems due to their inevitable high loss and high crosstalk. Summary of the invention
[0003] The embodiments of the present application provide a method and system for optimizing a terahertz adjustable power distribution synthesis structure, which are used to solve the problem that traditional terahertz planar metal structures cannot be integrated into miniaturized systems, and to solve the performance problem of the power distribution structure in current terahertz high-power source amplification systems.
[0004] The present application provides a method for optimizing a terahertz adjustable power distribution synthesis structure, including:
[0005] Design the terahertz T-junction power distribution synthesis structure for the required frequency band;
[0006] According to the chemical potential and relaxation time of graphene, the relevant dispersion curve is simulated and calculated;
[0007] Determining the electrical parameters of graphene in a required frequency band according to the dispersion curve, and constructing a corresponding absorption matching load according to the electrical parameters;
[0008] According to the microwave network, the terahertz T-junction power distribution synthesis structure is slotted, and the absorption matching load is connected to the slotted position to obtain a terahertz adjustable power distribution synthesis structure based on graphene absorption material;
[0009] The outputs of both ends of the terahertz adjustable power distribution synthesis structure are sampled and transmitted back to the control device to calculate the isolation degree;
[0010] According to the calculated isolation, the conductivity of the graphene absorption matching load is adjusted so that it meets the optimal isolation within the working frequency band.
[0011] Optionally, according to the chemical potential and relaxation time of graphene, the simulation calculates the relevant dispersion curve by calculating two electrical parameters of the surface wave propagation constant when the electromagnetic wave propagates on the surface of the graphene thin layer, wherein the surface wave propagation constant during propagation satisfies the following formula:
[0012]
[0013] Among them, ω is the angular frequency of the electromagnetic wave, ε1 and ε2 are the dielectric constants of the upper and lower media of graphene, σ is the conductivity of graphene, and k spp is the propagation constant of SPP surface wave propagating on the graphene surface;
[0014] Based on the calculated relationship between the surface wave propagation constant and frequency, the relevant dispersion curve is obtained.
[0015] Optionally, the electrical parameters of the graphene in the desired frequency band are determined by the voltage between the graphene thin layer and the reference ground;
[0016] The electrical conductivity of graphene satisfies:
[0017]
[0018] Among them, k B is the Boltzmann constant, h is the Planck constant, μ c is the chemical potential of graphene, τ is the electron relaxation time on the graphene surface;
[0019] Adjusting the voltage of the reference ground to change the electrical parameter characteristics of graphene;
[0020] Optionally, the surface resistivity of graphene and its chemical potential μ c The chemical potential μ of graphene is changed by adjusting the voltage across the graphene. c satisfy:
[0021]
[0022] Where ε0 represents the dielectric constant of vacuum, ε r Relative dielectric constant, n s represents the two-dimensional surface charge density of graphene, q e Represents the unit charge.
[0023] Optionally, the following feasibility steps are also included:
[0024] Define the input port and output port, and establish the corresponding normalized scattering matrix based on basic microwave theory;
[0025] The isolation of the output port is calculated according to the normalized scattering matrix, slotting is performed based on the isolation, and matching is performed at the slots, so that each port is in a matching state in combination with the normalized scattering matrix after slotting.
[0026] Optionally, according to the calculated isolation, the conductivity of the graphene absorption matching load is adjusted so that it meets the optimal isolation within the working frequency band, including: according to the conductivity of the graphene medium, the impedance is adjusted so that matching is achieved at the slot.
[0027] Optionally, the method further includes: adjusting the voltage across the graphene, sampling port isolation, and optimizing the voltage based on the sampled port isolation.
[0028] The embodiment of the present application also proposes a terahertz adjustable power distribution synthesis structure optimization system, including a processor and a memory, wherein the memory stores a computer program, and when the computer program is executed by the processor, the steps of the terahertz adjustable power distribution synthesis structure optimization method as described above are implemented.
[0029] The method of the embodiment of the present application solves the problem that the traditional terahertz planar metal structure cannot be integrated into a miniaturized system, and solves the performance problem of the power distribution structure in the current terahertz high-power source amplification system.
[0030] The above description is only an overview of the technical solution of the present application. In order to more clearly understand the technical means of the present application, it can be implemented in accordance with the contents of the specification. In order to make the above and other purposes, features and advantages of the present application more obvious and easy to understand, the specific implementation methods of the present application are listed below. BRIEF DESCRIPTION OF THE DRAWINGS
[0031] Various other advantages and benefits will become apparent to those of ordinary skill in the art by reading the detailed description of the preferred embodiments below. The accompanying drawings are only for the purpose of illustrating the preferred embodiments and are not to be considered as limiting the present application. Also, the same reference symbols are used throughout the accompanying drawings to represent the same components. In the accompanying drawings:
[0032] Figure 1 The flowchart of the adjustable power distribution synthesis structure optimization method according to the embodiment of the present application is shown;
[0033] Figure 2 The adjustable power distribution synthesis structure of the embodiment of the present application is shown;
[0034] Figure 3 The diagram is a schematic diagram showing the relationship between the graphene electrical parameters and its surface conductivity of the adjustable power distribution synthesis structure of the embodiment of the present application;
[0035] Figure 4 The diagram is a schematic diagram showing the relationship between the graphene electrical parameters of the adjustable power distribution synthesis structure of the embodiment of the present application and the dielectric constant of the medium underneath and the bias voltage at both ends;
[0036] Figure 5 It is a schematic diagram showing the comparison between the S parameters of the adjustable power distribution synthesis structure of the embodiment of the present application and the S parameters of the traditional T-junction power divider;
[0037] Figure 6 Schematic diagram of the comparison between the isolation of the adjustable power distribution synthesis structure of the embodiment of the present application and the traditional T-junction power divider;
[0038] Figure 7 Schematic diagram of the relationship between graphene electrical parameters and isolation of the adjustable power distribution synthesis structure of the embodiment of the present application. DETAILED DESCRIPTION
[0039] The exemplary embodiments of the present disclosure will be described in more detail below with reference to the accompanying drawings. Although the exemplary embodiments of the present disclosure are shown in the accompanying drawings, it should be understood that the present disclosure can be implemented in various forms and should not be limited by the embodiments set forth herein. On the contrary, these embodiments are provided to enable a more thorough understanding of the present disclosure and to fully convey the scope of the present disclosure to those skilled in the art.
[0040] Graphene is a single-atom-thick layer of carbon atoms arranged in a honeycomb lattice. Graphene has excellent structural and electrical properties. Due to its extremely small thickness, graphene can be well integrated into various terahertz monolithic circuits. The characteristics of graphene enable it to support surface plasmon effects in the terahertz band. The plasmon effect refers to the phenomenon that electromagnetic waves propagate along the surfaces of metals and dielectrics in the visible light band. Since the plasmon surface waves are highly bound to the surfaces of dielectrics and metal layers, they have low transmission losses and have broad application prospects for current high-speed communication radar systems. Compared with artificial plasmons realized using metal subwavelength periodic structures in this frequency band, graphene has better adjustable characteristics and easy processing.
[0041] Based on the adjustable characteristics of graphene and its good matching absorption characteristics in the low terahertz frequency band, this application constructs an optimization method for a high-isolation adjustable terahertz power distribution synthesis structure. By sampling the isolation of the two output ports, the isolation within the working frequency band can be optimized in real time. The specific embodiment of this application provides a method for optimizing a terahertz adjustable power distribution synthesis structure, such as Figure 1 , Figure 2 As shown, including:
[0042] In step S101, a terahertz T-junction power distribution synthesis structure of a required frequency band is designed.
[0043] In step S102, the relevant dispersion curve is simulated and calculated according to the chemical potential and relaxation time of graphene.
[0044] In step S103, the electrical parameters of the graphene in the required frequency band are determined according to the dispersion curve, and a corresponding absorption matching load is constructed according to the electrical parameters.
[0045] In step S104, the terahertz T-junction power distribution synthesis structure is slotted according to the microwave network, and the absorption matching load is connected to the slotted position to obtain a terahertz adjustable power distribution synthesis structure based on graphene absorption material.
[0046] In step S105, the outputs of both ends of the terahertz adjustable power distribution synthesis structure are sampled and transmitted back to the control device to calculate the isolation.
[0047] In step S106, the conductivity of the graphene absorption matching load is adjusted according to the calculated isolation so as to satisfy the optimal isolation within the working frequency band.
[0048] In some embodiments, the method further includes: adjusting the voltage across the graphene, sampling the port isolation, and optimizing the voltage according to the sampled port isolation.
[0049] In a specific example, a microwave probe is used to sample the two output ports of the terahertz adjustable power distribution synthesis structure, and a detector or a high-speed analog-to-digital conversion chip is used to transmit the output port power back to a PC or FPGA in real time for isolation calculation. The voltage at both ends of the graphene is optimized in real time according to the sampled isolation to achieve the optimization of isolation in each working frequency band, wherein the isolation is calculated in the following way:
[0050]
[0051] Port 2 and port 3 are two output ports of the terahertz adjustable power distribution synthesis structure.
[0052] In a specific embodiment, the voltage optimization method uses a genetic algorithm to perform a minimum value search algorithm, with the current operating frequency, the bias voltage at both ends of the graphene and the current isolation degree sampled and calculated as initial conditions, and the optimization is performed with the minimum isolation degree as the goal. The genetic algorithm uses a mathematical method and computer simulation calculation to convert the problem-solving process into a process similar to the crossover and mutation of chromosome genes in biological evolution. When solving more complex combinatorial optimization problems, it is usually possible to obtain better optimization results faster than some conventional optimization algorithms. In a specific example, the genetic algorithm can also be replaced by a gradient descent optimization algorithm.
[0053] The method of the embodiment of the present application solves the problem that the traditional terahertz planar metal structure cannot flexibly adjust the performance of microwave devices according to working conditions, and solves the performance problem of the power distribution structure in the current terahertz high-power source amplification system.
[0054] Figure 3 A graph showing the relationship between the electrical parameters of graphene and the changes in its surface conductivity in an intelligent terahertz adjustable power distribution synthesis structure according to an embodiment of the present application is shown. Figure 4 A graph showing the relationship between the electrical parameters of graphene and the dielectric constant of the medium underneath and the bias voltage at both ends in an intelligent terahertz adjustable power distribution synthesis structure of an embodiment of the present application is shown. Figure 5 A comparison diagram of the S parameters of an intelligent terahertz adjustable power distribution synthesis structure of an embodiment of the present application and the S parameters of a traditional T-junction power divider is shown. Figure 6 A comparison chart of the isolation of an intelligent terahertz adjustable power distribution synthesis structure according to an embodiment of the present application and a traditional T-junction power divider is shown. Figure 7 FIG. 1 shows a graph showing the relationship between graphene electrical parameters and isolation in an intelligent terahertz adjustable power distribution synthesis structure according to an embodiment of the present application. Figure 3-Figure 7 As shown, in some embodiments, according to the chemical potential and relaxation time of graphene, the relevant dispersion curve is simulated and calculated by calculating two electrical parameters of the surface wave propagation constant when the electromagnetic wave propagates on the surface of the graphene thin layer, wherein the surface wave propagation constant satisfies the following formula during propagation:
[0055]
[0056] Among them, ω is the angular frequency of the electromagnetic wave, ε1 and ε2 are the dielectric constants of the upper and lower media of graphene, σ is the conductivity of graphene, and k spp is the propagation constant of SPP surface wave propagating on the graphene surface;
[0057] Based on the calculated relationship between the surface wave propagation constant and frequency, the relevant dispersion curve is obtained.
[0058] In some embodiments, the electrical parameters of graphene in a desired frequency band are determined by the voltage between the graphene thin layer and a reference ground;
[0059] The electrical conductivity of graphene satisfies:
[0060]
[0061] Among them, k B is the Boltzmann constant, h is the Planck constant, μ c is the chemical potential of graphene, τ is the electron relaxation time on the graphene surface;
[0062] The voltage of the reference ground is adjusted to change the electrical parameter characteristics of graphene.
[0063] In some embodiments, the surface resistivity of graphene and its chemical potential μ c The chemical potential μ of graphene is changed by adjusting the voltage across the graphene. c satisfy:
[0064]
[0065] Where ε0 represents the dielectric constant of vacuum, ε r Relative dielectric constant, n s represents the two-dimensional surface charge density of graphene, q e Represents the unit charge.
[0066] In some embodiments, the following feasibility steps are also included:
[0067] Define the input port and output port, and establish the corresponding normalized scattering matrix according to the basic microwave theory. In the specific example, according to the basic microwave theory, the three-port network cannot simultaneously meet reciprocity, losslessness and perfect matching. Define the input port as 1, and the two output ports as port 2 and port 3. If port 1 matches, the corresponding normalized scattering matrix is:
[0068]
[0069] According to calculation, the isolation from port 2 to port 3 is only 6dB. Slot the three-port network and match it at the slot. The other three ports can be matched, and the corresponding scattering matrix is:
[0070]
[0071] The isolation of the output port is calculated according to the normalized scattering matrix, slotting is performed based on the isolation, and matching is performed at the slots, so that each port is in a matching state in combination with the normalized scattering matrix after slotting.
[0072] In some embodiments, according to the calculated isolation, the conductivity of the graphene absorption matching load is adjusted so that it meets the optimal isolation within the working frequency band, including: according to the conductivity of the graphene medium, the impedance is adjusted so that matching is achieved at the slot.
[0073] Based on the above embodiment, when the slot is fully matched, its isolation can be close to infinity in theory. In a specific example, the impedance of graphene is regulated according to the conductivity formula of graphene under two layers of medium, so that the slot is matched, thereby achieving a higher isolation. By adjusting the conductivity characteristics of graphene, it can work in the target frequency band, thereby increasing the working frequency band range of the structure.
[0074] The method of the present application solves the problem that the traditional waveguide T-junction power divider has low port isolation, and ideally the two ports have a maximum isolation of only 6 dB, which limits its further application.
[0075] The method of the present application solves the problem that in order to improve the isolation of the power divider output port, it is inevitable to introduce an isolation port, such as a resistor and an absorbing material. However, these introduced materials cannot be well integrated on the power divider, which will introduce additional insertion loss and return loss.
[0076] This application uses a graphene terahertz planar structure to solve the problem that the traditional terahertz planar metal structure cannot be further integrated into a miniaturized system due to its inevitable high loss and high crosstalk. This application uses the adjustable characteristics of graphene materials to intelligently adjust the current power synthesis equipment to adapt to the application environment in different situations.
[0077] The embodiment of the present application also proposes a terahertz adjustable power distribution synthesis structure optimization system, including a processor and a memory, wherein the memory stores a computer program, and when the computer program is executed by the processor, the steps of the terahertz adjustable power distribution synthesis structure optimization method as described above are implemented.
[0078] It should be noted that in the various embodiments of the present application, the terms "include", "comprise" or any other variants thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements includes not only those elements, but also includes other elements not explicitly listed, or also includes elements inherent to such process, method, article or device. In the absence of further restrictions, an element defined by the sentence "includes a ..." does not exclude the presence of other identical elements in the process, method, article or device including the element.
[0079] The serial numbers of the above-mentioned embodiments of the present application are for description only and do not represent the advantages or disadvantages of the embodiments.
[0080] Through the description of the above implementation methods, those skilled in the art can clearly understand that the above-mentioned embodiment methods can be implemented by means of software plus a necessary general hardware platform, and of course by hardware, but in many cases the former is a better implementation method. Based on such an understanding, the technical solution of the present application, or the part that contributes to the prior art, can be embodied in the form of a software product, which is stored in a storage medium (such as ROM / RAM, a magnetic disk, or an optical disk), and includes a number of instructions for a terminal (which can be a mobile phone, a computer, a server, an air conditioner, or a network device, etc.) to execute the methods described in each embodiment of the present application.
[0081] The embodiments of the present application are described above in conjunction with the accompanying drawings, but the present application is not limited to the above-mentioned specific implementation methods. The above-mentioned specific implementation methods are merely illustrative and not restrictive. Under the guidance of the present application, ordinary technicians in this field can also make many forms without departing from the purpose of the present application and the scope of protection of the claims, all of which are within the protection of the present application.
Claims
1. A method for optimizing a terahertz adjustable power distribution synthesis structure, characterized in that: include: Design the terahertz T-junction power distribution synthesis structure for the required frequency band; According to the chemical potential and relaxation time of graphene, the relevant dispersion curve is simulated and calculated; Determining the electrical parameters of graphene in a required frequency band according to the dispersion curve, and constructing a corresponding absorption matching load according to the electrical parameters; According to the microwave network, the terahertz T-junction power distribution synthesis structure is slotted, and the absorption matching load is connected to the slotted position to obtain a terahertz adjustable power distribution synthesis structure based on graphene absorption material; The outputs of both ends of the terahertz adjustable power distribution synthesis structure are sampled and transmitted back to the control device to calculate the isolation degree; According to the calculated isolation, the conductivity of the graphene absorption matching load is adjusted so that it meets the optimal isolation within the working frequency band.
2. The method for optimizing the terahertz adjustable power distribution synthesis structure according to claim 1, characterized in that: According to the chemical potential and relaxation time of graphene, the simulation calculates the relevant dispersion curve by calculating the two electrical parameters of the surface wave propagation constant when the electromagnetic wave propagates on the surface of the graphene thin layer. The surface wave propagation constant during propagation satisfies the following formula: Among them, ω is the angular frequency of the electromagnetic wave, ε1 and ε2 are the dielectric constants of the upper and lower media of graphene, σ is the conductivity of graphene, and k spp is the propagation constant of SPP surface wave propagating on the graphene surface; Based on the calculated relationship between the surface wave propagation constant and frequency, the relevant dispersion curve is obtained.
3. The method for optimizing the terahertz adjustable power distribution synthesis structure according to claim 2, characterized in that: The conductivity of graphene in the desired frequency band is determined by the voltage between the graphene sheet and the reference ground; The electrical conductivity of graphene satisfies: Among them, k B is the Boltzmann constant, h is the Planck constant, μ c is the chemical potential of graphene, τ is the electron relaxation time on the graphene surface, T represents room temperature, σ R represents the real part of graphene conductivity, σ i represents the imaginary part of graphene conductivity, h represents the height of graphene from the reference ground; The voltage of the reference ground is adjusted to change the electrical parameter characteristics of graphene.
4. The method for optimizing the terahertz adjustable power distribution synthesis structure according to claim 3, characterized in that: It also includes the surface resistivity of graphene and its chemical potential μ c The chemical potential μ of graphene is changed by adjusting the voltage across the graphene. c satisfy: Where ε0 represents the dielectric constant in vacuum, ε r Relative dielectric constant, n s represents the two-dimensional surface charge density of graphene, q e Represents the unit charge.
5. The method for optimizing the terahertz adjustable power distribution synthesis structure according to claim 3, characterized in that: It also includes the following feasibility steps: Define the input port and output port, and establish the corresponding normalized scattering matrix based on basic microwave theory; The isolation of the output port is calculated according to the normalized scattering matrix, slotting is performed based on the isolation, and matching is performed at the slots, so that each port is in a matching state in combination with the normalized scattering matrix after slotting.
6. The method for optimizing the terahertz adjustable power distribution synthesis structure according to claim 5, characterized in that: According to the calculated isolation, the conductivity of the graphene absorption matching load is adjusted so that it meets the optimal isolation within the working frequency band, including: according to the conductivity of the graphene medium, the impedance is adjusted so that matching is achieved at the slot.
7. The method for optimizing the terahertz adjustable power distribution synthesis structure according to claim 6, characterized in that: Also includes: The voltage across the graphene is adjusted, the port isolation is sampled, and the voltage is optimized based on the sampled port isolation.
8. A terahertz adjustable power distribution synthesis structure optimization system, characterized in that: The method comprises a processor and a memory, wherein a computer program is stored in the memory, and when the computer program is executed by the processor, the steps of the method for optimizing the terahertz adjustable power distribution synthesis structure as claimed in any one of claims 1 to 7 are implemented.