Research On RCS Tunable Technology Based On Time Reversal

With the rapid development of wireless communication technology,low-cost,highgain,and compact antenna systems have attracted much attention to ensure reliable connections between communication systems.In order to ensure the high applicability of the antenna system in various scenarios,such as the target detection technology to increase the radar cross section(RCS)of the system,and the stealth technology to reduce the system RCS,etc.,the adjustment of the RCS parameters of the system based on the directional retrospective antenna has also become the focus of the research.Aiming at the problems of the traditional direction retrospective system including the inability of the corner reflector to modulate the backscattered signal and the low efficiency of the Van Atta array antenna,the direction retrospective antenna based on the time inversion theory is a new direction.The purpose of this thesis is to design and fabricate a directional retrospective antenna array with adjustable system RCS parameters.The main research contents include:1.Aiming at the problem that the traditional corner reflector system cannot modulate the backscattered signal,the retrospective antenna array system is designed based on the passive microwave device Rotman lens and the RCS parameters can be adjusted.The yoke phase response enables direction backtracking of the planar beam.A Rotman lens composed of 13 beam ports and 10 array ports is designed and operates at a center frequency of 10 GHz.The simulation results show that the lens has the output port characteristics of amplitude consistency and fixed phase difference distribution,and can achieve-45° to 45° beam scanning range.At the same time,an RCS control circuit composed of a switch,a circulator and an amplifier is designed at the connection of the lens beam port,and the RCS parameters of the system can be adjusted by adjusting the gain of the amplifier in the circuit.2.In view of the small radiation gain of a single patch antenna,a series-fed microstrip array antenna is designed based on the microstrip array antenna theory as a radiating element connected to the lens,which can achieve small return loss and high pattern.gain.At the same time,the whole system model is verified by full-wave electromagnetic simulation.The results show that the system can realize the direction backtracking of the plane wave input signal in the bandwidth range of 9.85 to 10.15 GHz.Then,by adjusting the RCS control circuit,the feasibility of adjusting the RCS parameters of the antenna array system through the circuit amplifier is verified.Finally,based on the design schematic diagram and simulation results,the physical structure of the timereversed direction retrospective antenna array prototype is produced.3.Aiming at the time-space-frequency inconsistency in direction backtracking under multi-platform conditions,a phase conjugate circuit suitable for distributed motion platforms is proposed based on time inversion theory.The circuit is mainly composed of a carrier extraction module and a frequency mixing module.Based on ADS The simulation environment models and simulates each component of the circuit to verify the feasibility of the circuit to achieve phase conjugation.