超材料微波磁导率色散行为的电可调控性研究

摘要

By embedding a capacity-variable diode into a split ring resonator （SRR）,it is found that the effective capacitance of such an SRR element can be varied by the biased voltage of diode.Therefore the resonance frequency and effective permeability of an SRR element can be tuned.Based on these results,a smart microwave magnetic metamaterial is proposed.Employing the finite-difference time-domain and retrieval method,the variations of resonance frequency and permeability of the SRR element are simulated and calculated by changing the biased voltage.It is found that with the decrease of capacitance due to the increase of biased voltage,the resonance frequencies are shifted towards lower values,and so are the resonance frequencies of permeability dispersion.Finally,the difference in permeability dispersion behavior between SRR structure and natural magnetic material （for instance,ferrite） has been pointed out.%研究在开口金属谐振环（SRR）结构嵌入一个电容二极管后,通过电压调控二极管的电容使得SRR结构的等效电容值发生改变,能实现对SRR的谐振频率和等效磁导率的调控,从而提出了一种智能的微波磁性超材料结构.采用时域差分有限元法（Finite-Difference Time-Domain）和恢复算法模拟了变容二极管的工作电压变化下,SRR结构谐振频率和磁导率的变化规律.研究结果表明工作电压增大使变容二极管的电容值减小时,将导致SRR结构的谐振频率向低频段移动,其磁导率的共振频率也将向低频移动.最后指出了SRR结构与常规磁性材料（如铁氧体）磁导率色散行为的不同之处.