Graphene Nonlinear Electromagnetic Characteristics Analysis And Application Research

With the rapid development of wireless communication systems,non-linear devices based on traditional materials and processes are facing more and more problems.As a new type of two-dimensional carbon-based material,graphene has broad application prospects in the field of high-frequency electronic devices by virtue of its unique nonlinear electromagnetic characteristics and dynamically adjustable characteristics.Therefore,it has important research significance for the analysis and application of nonlinear electromagnetic characteristics of graphene.Through the investigation of graphene nonlinear devices at home and abroad and the analysis of graphene nonlinear theory,the research and design of graphene nonlinear devices with different circuit structures were carried out,and the methods of recycling network,electrical bias and gas regulation were explored.The effect of the working efficiency of olefin nonlinear devices.This work includes the following aspects:(1)Through the basic theoretical analysis of the laws of electron motion,the nonlinear electromagnetic response of graphene materials is described in detail.The theoretical analysis of the third-order nonlinear effect of graphene shows that graphene materials have odd harmonic output characteristics under the excitation of electromagnetic waves.The theoretical analysis of the second-order nonlinear effect of graphene shows that the symmetry of the graphene material itself suppresses the second-order effect,but the second-order effect can be promoted through different forms of regulation.(2)Analysis and verification of the nonlinear characteristics of graphene circuits.The influence of contact metal and base material on the properties of graphene materials is simply analyzed.It can be seen from the analysis that the contact between graphene material and copper does not affect the inherent electronic properties of graphene,and the use of high dielectric constant substrate materials can reduce the impact on the performance of graphene materials.Tests on graphene circuits have shown that multilayer graphene materials produced by micromechanical peeling still have nonlinear characteristics when loaded onto the circuit.By comparing and analyzing the mixed spectrum of graphene mixer and anti-parallel Schottky diode mixer,the thirdorder nonlinear electromagnetic theory of graphene is verified.(3)Design of graphene frequency multiplier with controllable bias voltage.According to the nonlinear electromagnetic response theory and dynamically adjustable characteristics of graphene,a graphene frequency multiplier with controllable voltage was fabricated.The circuit structure of the frequency multiplier adopts a recycling network for optimal design.When the fundamental signal is 0.82 GHz and 16 d Bm,the minimum difference of the graphene frequency multiplier without bias voltage and recovery network is 26.72 d B;the frequency doubling loss is reduced by 3.04 d B;the application of bias control and recovery The network frequency doubling loss is reduced by 6.15 d B.The test results show that the application of bias voltage and the recovery network can improve the working efficiency of the graphene frequency multiplier.The graphene frequency multiplier with controllable voltage is triple frequency output without bias voltage,and it can realize double frequency output after applying bias voltage.Without changing the circuit structure,only the external bias voltage can change the frequency doubling times to achieve a broadband frequency doubling output.(4)Applied research on the nonlinear characteristics of graphene in gas environment.In the ammonia environment,the changes of graphene output harmonic power and DC resistance under different bias conditions were explored.A preliminary sensing experiment was carried out on butane gas.The test results found that the change rate of the output harmonic power of the graphene gas sensing circuit in the ammonia gas environment at 1V bias voltage is about 20% higher than the change rate of the DC resistance,and the third harmonic output power without bias voltage There is a slight increase.The graphene gas sensing circuit in the butane gas environment will also increase the output harmonic power of the second harmonic at a bias voltage of 1V.This paper analyzes the nonlinear characteristics of graphene and explores the specific applications of different characteristics.It has laid a foundation for in-depth exploration and research of graphene-based nonlinear devices,and also has important reference significance for the study of other nonlinear materials and circuits.