Isolator based on one-dimensional non-Hermi topology circuit structure

Abstract

The invention discloses an isolator based on a one-dimensional non-Hermite topology circuit structure, which is of a Su-Schriffer-Header (SSH) chain structure formed by alternately arranging a series of gain / loss modules, the loss module is formed by connecting a capacitor-inductor-resistor in parallel with a grounding resonance module, and the gain module is formed by connecting a capacitor-inductor-negative resistor in parallel with the grounding resonance module. The gain module and the loss module form a periodic unit through capacitive coupling, and different periodic units form a topological circuit structure through capacitive coupling. Wherein the loss module at the initial position of the circuit forms an input port of the isolator, and the gain module at the tail end position of the circuit forms an output port of the isolator. One-way signal transmission of the circuit is achieved by changing the proportion of gain and loss and the proportion of coupling capacitance in the periodic units and coupling capacitance between the periodic units. The system has high isolation and strong robustness.

Description

Technical Field

[0001] The present invention relates to the field of two-port unidirectional signal transmission, and in particular to an isolator based on a one-dimensional non-Hermitian topological circuit structure. Background Art

[0002] In recent years, non-reciprocal transmission devices, as core components of modern communication systems, have played an irreplaceable role in microwave engineering, radio frequency systems, and quantum information processing. Traditional isolators mainly use the magneto-optical effect of ferrite materials to achieve unidirectional signal transmission. However, such devices have inherent defects such as limited operating frequency band, large size, and difficulty in compatibility with planar integrated circuits. Although acoustic / optical isolator solutions based on nonlinear effects have made progress in miniaturization, their dependence on high-power excitation sources and dynamic stability issues have seriously restricted their practical applications.

[0003] With the development of non-Hermitian quantum physics and topological photonics theory, researchers have found that by introducing a gain / loss control mechanism, directional excitation of topological boundary states can be achieved in non-reciprocal systems. In particular, the one-dimensional non-Hermitian topological chain model, with its unique complex band structure, provides a new way to break the Lorentz reciprocity theorem. Existing experiments have proved that the non-Hermitian skin effect has a significant control ability on the propagation direction of electromagnetic waves, but related research is mostly concentrated in the theoretical verification stage, and a device design scheme with engineering practical value has not yet been formed. Therefore, it is very necessary to solve the above application problems and propose an isolator based on a one-dimensional non-Hermitian topological circuit structure. Summary of the invention

[0004] The purpose of the present invention is to address the deficiencies of the above-mentioned background technology and propose an isolator based on a one-dimensional non-Hermitian topological circuit structure, which eliminates the traditional isolator's dependence on ferrite materials. Compared with isolators of other technical routes, it introduces the robustness of the topological circuit, effectively improves the anti-interference ability of the isolator, and at the same time, thanks to the skin effect of the non-Hermitian topological circuit, improves the isolation of the isolator.

[0005] In order to solve the above technical problems, the specific technical solutions of the present invention are as follows: An isolator based on a one-dimensional non-Hermitian topological circuit structure, the isolator consists of N periodic units U through a coupling capacitor C b Each periodic unit U consists of a loss module A and a gain module B and a capacitor C connecting them. a The N periodic units are coupled through the capacitor C b To form a signal transition of a one-dimensional topological circuit. The signal input port of the loss module of the periodic unit U1 at the starting end of the circuit structure constitutes the input port IN of the isolator, and the periodic unit U1 at the end of the circuit structure NThe signal output port of the gain module constitutes the output port OUT of the isolator. By adjusting the ratio of coupling capacitance between basic units and coupling capacitance within the unit, as well as the gain / loss ratio of loss module and gain module within the periodic unit, high isolation and stable non-reciprocal transmission can be achieved.

[0006] Furthermore, the circuit structure is formed by a series of loss modules and gain modules arranged in cascade periodically, forming a chain circuit structure in the sequence of ABAB, with C between AB and AB. a Connect coupling.

[0007] Furthermore, the number N of periodic units U must be a positive integer. In order to meet the topological conditions, the value of N is greater than or equal to 10.

[0008] Furthermore, the loss module A included in the periodic unit U is composed of a first inductor L1, a positive resistor R1, and a first capacitor C1 connected in parallel. The entire loss module A is grounded, and one end is connected to the coupling capacitor C1 between the periodic units. b The other end is connected to the coupling capacitor C in the periodic unit a .

[0009] Furthermore, the gain module B included in the periodic unit U is composed of a second inductor L2, a negative resistor -R2, and a second capacitor C2 connected in parallel. The overall gain module B is grounded, and one end is connected to the coupling capacitor C in the periodic unit. a The other end is connected to the coupling capacitor C between periodic units. b .

[0010] Furthermore, the first period unit U1 at the start end of the circuit is connected to the input port at one end and to the inter-unit coupling capacitor C at the other end. b The last cycle unit U at the end of the circuit N One end is connected to the output port, and the other end is connected to the inter-unit coupling capacitor C b .

[0011] Furthermore, the first inductor L1 and the first capacitor C1 of the loss module in the periodic unit U are respectively equal to the second inductor L2 and the second capacitor C2 of the gain module; the resistance value of the positive resistor R1 in the loss module is equal to the absolute value of the resistance value of the negative resistor -R2 in the gain module when working in the linear region.

[0012] Furthermore, the inter-cycle coupling capacitor simulates the transition between the cycle unit and the adjacent cycle unit, and the intra-cycle coupling capacitor C a The transition between the simulation loss module and the gain module. The coupling capacitance C between the periodic units b And the coupling capacitance C within the period unit a Different. The coupling capacitance C in the period unit a The capacitance value is between; wherein C1 is the first capacitor in the loss module A, R1 is the positive resistor in the loss module A, and L1 is the first inductor in the loss module A.

[0013] Furthermore, the coupling capacitance C between periodic units b The capacitance value must be smaller than the coupling capacitance C a The capacitance value is set to make it and the coupling capacitance C in the period unit a The capacitance value ratio meets the transition conditions of the topological circuit.

[0014] Furthermore, the periodic units and the coupling capacitors between the units are connected in series to form a topological circuit structure, and the topological performance and non-Hermitian skin effect of the circuit structure are detected, so that the circuit satisfies the condition that when a signal is input from the input port, it is output from the output port; and when a signal is input from the output port, it cannot be output from the input port, thus forming an isolator for unidirectional signal transmission.

[0015] The isolator based on a one-dimensional non-Hermitian topological circuit structure of the present invention has the following advantages: (1) The present invention utilizes N periodic units connected in series through coupling capacitors to form a one-dimensional non-Hermitian topological circuit structure. By adjusting the gain-loss ratio of the loss module and the gain module inside the periodic unit and the proportional relationship between the coupling capacitor inside the periodic unit and the coupling capacitor between the periodic units, the skin effect of the non-Hermitian topological circuit is utilized to achieve control of the signal transmission direction.

[0016] (2) The circuit topology protection mechanism is introduced into the isolator to improve the robustness of the isolator. Compared with the traditional ferrite isolator, this system has the advantages of small size, easy integration, easy preparation, strong anti-interference ability and high isolation. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 A schematic diagram of an isolator based on a one-dimensional non-Hermitian topological circuit structure of the present invention; Figure 2 An equivalent circuit diagram of an isolator based on a one-dimensional non-Hermitian topological circuit structure of the present invention; DETAILED DESCRIPTION

[0018] In order to better understand the structure and function of the present invention, the technical solution of an isolator based on a one-dimensional non-Hermitian topological circuit structure of the present invention will be described more clearly and in detail in conjunction with the relevant drawings. It should be noted that the "first", "second", etc. in the specification and claims of the present invention are used to distinguish similar objects, and are not necessarily used to describe a specific order or sequence.

[0019] like Figure 1As shown, an isolator based on a one-dimensional non-Hermitian topological circuit structure is a two-port device, wherein the input port IN is the input port of the signal, and the output port OUT is the output port of the signal. When the signal is input from the input port IN, the signal is transmitted in the forward direction and amplified by the gain module in the periodic unit, and output from the output port OUT. At this time, due to the non-Hermitian skin effect of the topological circuit structure, the signal maintains the characteristic of unidirectional transmission, and the reverse signal cannot flow back from the output port OUT to the input port, thereby achieving the effect of isolating the signal by the isolator.

[0020] like Figure 2 As shown, the isolator consists of N periodic units U through the inter-unit coupling capacitor C b In series, N is a positive integer, simulating a one-dimensional non-Hermitian topological circuit structure. Each periodic unit contains a loss module A and a gain module B and a capacitor C connecting them. a The coupling capacitor C2 is used to simulate the inter-unit transition in the one-dimensional non-Hermitian topology circuit structure. The signal input port of the loss module of the periodic unit U1 at the beginning of the circuit structure constitutes the input port IN of the isolator, and the periodic unit U1 at the end of the circuit structure N The signal output port of the gain module constitutes the output port OUT of the isolator. By adjusting the ratio of the coupling capacitor C2 between the basic units and the coupling capacitor C1 within the unit, as well as the gain / loss ratio of the loss module A and the gain module B within the periodic unit U, high isolation and stable non-reciprocal transmission can be achieved.

[0021] The circuit structure is formed by a series of loss modules A and gain modules B arranged in cascade periodically, forming a chain circuit structure in the sequence of ABAB. The number of periodic units N must be a positive integer. In order to meet the topological conditions, the value of N is greater than or equal to 10. Each periodic unit contains a loss module A and a gain module B and a capacitor C connecting them. a The loss module A included in the periodic unit U is composed of a first inductor L1, a positive resistor R1, and a first capacitor C1 connected in parallel. The entire loss module A is grounded, and one end is connected to the inter-unit coupling capacitor C b The other end is connected to the coupling capacitor C in the period unit. a The gain module B included in the periodic unit U is composed of a second inductor L2, a negative resistor -R2, and a second capacitor C2 in parallel. The overall gain module B is grounded, and one end is connected to the coupling capacitor C in the periodic unit. a The other end is connected to the coupling capacitor C between periodic units. b The first period unit U1 at the start of the circuit is connected to the input port at one end and the inter-unit coupling capacitor C at the other end. b The last cycle unit U at the end of the circuit N One end is connected to the output port, and the other end is connected to the inter-unit coupling capacitor Cb .

[0022] Inter-cycle coupling capacitor C b Simulate the transition between the periodic unit and the adjacent periodic unit, the coupling capacitance C within the periodic unit a Simulate the transition between loss block A and gain block B. The coupling capacitor C a With C b The value of capacitor C b The value must be smaller than the capacitance C a By adjusting the capacitance C a , C b ratio, the characteristics of the topological circuit structure can be realized.

[0023] The first inductor L1 and the first capacitor C1 of the loss module in the periodic unit are respectively equal to the second inductor L2 and the second capacitor C2 of the gain module; the resistance value of the positive resistor R1 in the loss module is equal to the absolute value of the resistance value of the negative resistor -R2 in the gain module.

[0024] Set the coupling capacitance C within the cycle unit a The capacitance value satisfies the formula , where C1 is the first capacitor in the loss module A, R1 is the positive resistor in the loss module A, and L1 is the first inductor in the loss module A. Ensure that the periodic unit works in the parity-time symmetry breaking region.

[0025] Repeat the above steps and adjust the coupling capacitor C in the period unit according to the direction of signal transmission. a The coupling capacitance C between the periodic units b The ratio meets the requirements of non-Hermitian topology circuit structure and realizes stable unidirectional transmission of signals.

[0026] It is to be understood that the present invention is described by some embodiments, and it is known to those skilled in the art that various changes or equivalent substitutions may be made to these features and embodiments without departing from the spirit and scope of the present invention. In addition, under the teachings of the present invention, these features and embodiments may be modified to adapt to specific circumstances and materials without departing from the spirit and scope of the present invention. Therefore, the present invention is not limited by the specific embodiments disclosed herein, and all embodiments falling within the scope of the claims of this application are within the scope of protection of the present invention.

Claims

1. An isolator based on a one-dimensional non-Hermitian topological circuit structure, characterized in that: The isolator consists of N periodic units U through coupling capacitors C b In series, N is a positive integer; each period unit U includes a loss module A and a gain module B and a capacitor C connecting them. a ; N periodic units U are coupled through the capacitor C b To form a signal transition of a one-dimensional topological circuit; wherein the signal input port of the loss module of the periodic unit U1 at the starting end of the isolator constitutes the input port IN of the isolator, and the periodic unit U N The signal output port of the gain module constitutes the output port OUT of the isolator.

2. The isolator based on a one-dimensional non-Hermitian topological circuit structure according to claim 1, characterized in that: N periodic units U form a chain circuit structure in the sequence of ABAB, with C between AB and AB. a Connect coupling.

3. The isolator based on a one-dimensional non-Hermitian topological circuit structure according to claim 1, characterized in that: The value of the number N of periodic units U is greater than or equal to 10.

4. The isolator based on a one-dimensional non-Hermitian topological circuit structure according to claim 1, characterized in that: The loss module A included in the periodic unit U is composed of a first inductor L1, a positive resistor R1, and a first capacitor C1 connected in parallel. The entire loss module A is grounded, and one end is connected to the coupling capacitor C1 between the periodic units. b The other end is connected to the coupling capacitor C in the periodic unit a .

5. The isolator based on a one-dimensional non-Hermitian topological circuit structure according to claim 1, characterized in that: The gain module B included in the periodic unit U is composed of a second inductor L2, a negative resistor -R2, and a second capacitor C2 connected in parallel. The overall gain module B is grounded, and one end is connected to the coupling capacitor C in the periodic unit. a The other end is connected to the coupling capacitor C between periodic units. b .

6. The isolator based on a one-dimensional non-Hermitian topological circuit structure according to claim 1, characterized in that: The first period unit U1 at the starting end of the circuit is connected to the input port at one end and the inter-unit coupling capacitor C at the other end. b ; The last period unit U at the end of the circuit N One end is connected to the output port, and the other end is connected to the inter-unit coupling capacitor C b .

7. The isolator based on a one-dimensional non-Hermitian topological circuit structure according to claim 1, characterized in that: The coupling capacitor C in the period unit a The capacitance value is between; wherein C1 is the first capacitor in the loss module A, R1 is the positive resistor in the loss module A, and L1 is the first inductor in the loss module A.

8. The isolator based on a one-dimensional non-Hermitian topological circuit structure according to claim 1, characterized in that: The inter-unit coupling capacitance C b The capacitance value is smaller than the coupling capacitance C in the unit a The capacitance value is set to make it and the coupling capacitance C in the unit a The capacitance value ratio meets the transition conditions of the topological circuit.

9. The isolator based on a one-dimensional non-Hermitian topological circuit structure according to claim 1, characterized in that The first inductor L1 and the first capacitor C1 of the loss module in the periodic unit U are respectively equal to the second inductor L2 and the second capacitor C2 of the gain module; the resistance value of the positive resistor R1 in the loss module is equal to the absolute value of the resistance value of the negative resistor -R2 in the gain module.

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