Research On Radiation And Signal Transmission Characteristics Of Plasma Sheathed Magnetic Window Antenna

When vehicles fly in the nearby space at supersonic speeds,a layer of plasma sheath,is wrapped around the hypersonic,which has strong influences on the measurement signals and navigation signals,causing reflection,refraction and absorption.These effects lead to the communication blackout issue,which makes the electromagnetic waves cannot be received and identified by the antenna.This contradicts the need for the vehicles to receive communication signals without interruption.Hence,it is urgent to find a technology to alleviate the problem of communication blackout.Scholars from all over the world have proposed a variety of methods to solve the communication blackout issue,Among them,apply magnetic field is one of the most feasible engineering methods,the method creates a magnetic window for electromagnetic wave transmission by applying a magnetic field in the antenna area.First,this paper studies the numerical simulation process of applying a magnetic field to obtain a magnetic window,and obtains the plasma sheath before and after the magnetic window is applied to the hypersonic.Secondly,based on FDTD simulation,the two communication methods of the hypersonic transmitting electromagnetic waves and receiving communication signals are studied.The simulation model includes antenna,hypersonic and plasma sheath.Therefore,the FDTD algorithm for simulating the antenna radiation pattern is studied,and an effective simulation method is proposed to simulate the process of transmitting electromagnetic waves from a hypersonic vehicle.The radiation pattern of the antenna before and after the apply magnetic window is compared to verify that the apply magnetic field improves the antenna pattern.Finally,the propagation characteristics of the electric wave in the plasma are studied,and the reflection and transmission coefficients of the electric wave transmitted in the plasma sheath before and after the magnetic window are simulated.In order to study the influence of the applied magnetic field on the transmission quality of communication signals,suppose the hypersonic needs to receive measurement and control signals from the ground or navigation signals from satellites.When electromagnetic waves reach the hypersonic,they can be regarded as plane waves and received at the antenna.To this end,the modulation and demodulation algorithms for QPSK and 2FSK signals are studied,and a set of simulation methods are proposed to simulate the process of receiving signals from a hypersonic vehicle.It is verified that the apply magnetic field plays an important role in improving the communication quality.In this paper,the application of apply magnetic field to alleviate the problem of communication black barriers has been simulated,avoiding complicated and expensive flight experiments,can provide theoretical basis and simulation data for solving black barrier problems,which is also one of the innovations of this paper.