Research On Radome Based On Reconfigurable FSS

With the development of communication technology,the electromagnetic interference between antennas of communication equipment is getting more and more serious,and a radome is needed to ensure the communication quality of the equipment.The traditional radome can protect the antenna from natural disasters,and its electromagnetic regulation capability needs to be improved.Compared with the classical Frequency Selective Surface(FSS),the reconfigurable frequency selective surface can regulate and control the fixed electromagnetic characteristics so that it can change accordingly with the changes of the external electromagnetic environment.Applying the reconfigurable frequency selection surface to the radome design can effectively improve the antenna's resistance to electromagnetic interference.This thesis designs three structures to solve the problem that the frequency of the passband of the traditional FSS radome is not adjustable.It is developed in three aspects: single passband adjustable,dual-band adjustable and terahertz adjustable,using HFSS electromagnetic simulation design and analysis methods.In-depth study of the reconfigurable FSS radome.This thesis designs three kinds of structure FSS to solve the problem that the passband frequency of the traditional radome is not adjustable.The research work is carried out from three aspects: single passband adjustable,dual-band adjustable and terahertz band adjustable,using theoretical analysis and HFSS electromagnetic simulation Design a combined approach to conduct in-depth research on reconfigurable FSS.(1)Design a frequency selective surface with a single notch asymmetric structure,change the resonance characteristics through the rotation angle,and optimize its structure through the electromagnetic simulation software HFSS.Based on the single-notch ring,the double-notch ring FSS structure is designed.At an angle of 0°,the center frequency of the passband is 4.6GHz.By rotating 90° counterclockwise,the center frequency of the passband becomes 3.4GHz,and the passband is realized.Switching from C band(4-8GHz)to S band(2-4GHz).(2)The frequency selection surface of the PIN diode is designed to be loaded.The center frequency of the pass band is 4.5GHz when the PIN diode is in the on state,and 2.9GHz is the center frequency of the pass band in the off state.The pass band is changed from the C band to the S band.In order to make FSS continuously adjustable,a dual-band FSS loaded with a varactor diode is designed.The two passbands are in the C and S bands,respectively.When the capacitance value of the varactor diode changes from 0.12 p F to 0.8p F,the center frequency of the C-band passband is reduced from 5.56 GHz to 5.39GHz;the center frequency of the S-band passband is reduced from 3.82 GHz to 3.46 GHz,which realizes double pass continuously adjustable with operating frequency.(3)The electromagnetic properties of the electromagnetic sensitive material graphene in terahertz are studied and calculated,and a double concentric circular cross structure FSS loaded with graphene is designed to extend the passband characteristics from the microwave band to the terahertz wave band and achieve a small FSS size change.By changing the chemical potential of graphene from 0.2e V to 0.9e V,the center frequency of the passband is changed from 2.58 THz to 3.31 THz,and the transmission coefficients are all greater than 0.95,achieving the adjustment of the terahertz band.The three frequency selection surfaces designed have the advantages of easy adjustment and simple structure,and have application potential in reconfigurable radomes.