Investigation Of X-band High Power Microwave Radome By Left-handed Material

Left-handed material (LHM) is a novel electromagnetic metamaterial with itselectric field vector, magnetic field vector, wave vector constructing left-criterion.Because of its negative refractive index, the LHM exhibits reversed Doppler Effect, andreversed Cerenkov radiation. Applying it to microwave antenna, the beams can befocused and gain can be improved. In this thesis, a novel X-Band High PowerMicrowave (HPM) radome is studied to verify that LHM can operate in HPM system. Itcannot be found that LHM had been employed to work at HPM system before. So thesubject research has the important value and significance.Firstly, the research progress of LHM and the application of LHM radome inmicrowave band are introduced. Then, the research situation of HPM antenna ispresented. The subject purpose and meaning are briefly summarized. By analyzingLorentz-Model and Drude-Model, it is verified that the refractive index can be negative.In addition, with finite member method (FMM) and finite difference time domain(FDTD), the method to solve the electromagnetic field in LHM is introduced. Theconstructive parameter retrieval methods are studied mostly, providing importantsupport for the next step designing LHM structure.LHM fishnet unit structure used in radome is designed. The negative of effectivepermittivity, permeability and refraction can be obtained. The LHM radome is loaded tothe horn antenna to simulate. It is found that the beams are focused and the gain isimproved. The gain is raised by4.5dB at8.9GHz. By simulation and parameteroptimization, the X-Band LHM radome is obtained to apply to HPM horn antenna.By monitoring electric field distribution, the power capacity of radome is analyzed.The analysis shows that when emitting1GW HPM, the electric intensity of inner andouter face of radome is large. If the radome is exposed to the air, breakdown is easilyhappening. Therefore, design for radome unit structure is improved to strengthen thepower capacity and a scheme of LHM radome used in HPM is proposed.Finally, the LHM radome is fabricated by printed circuit technique andinvestigated experimentally. In the experiment, the radiation and gain of the hornantenna without and with1-4layer LHM radome are measured. The results show that,with one layer LHM radome, the gain of the horn antenna can be raised about9.64dBat9.32GHz.