Dielectric resonator is a kind of important building block for metamaterials. Here, we numerically investigated the resonance modes excited in the dielectric resonator whose cross section has different ratios of the length to width. It is found that the cross-sectional aspect ratio has great influence on the excitation sequence of the resonance modes. The magnetic resonance mode is firstly excited for the aspect ratio smaller than 2.2, whereas it is excited at the second resonance for the ratio lager than 2.2. As the turning point, i. e. with the aspect ratio of 2. 2, the magnetic mode cannot be achieved. The calculations also show that the magnetic resonance can be tuned by adjusting the direction of the incident electromagnetic wave, thus achieving the polarization control of electromagnetic response. This study provides valuable information for the design and research of novel dielectric-based metamaterials.%本文利用电磁场数值计算方法研究了横截面具有不同长宽比例的电介质柱的电磁共振模式,发现横截面长宽.比例影响电介质柱共振模式的激发顺序.截面长宽比小于2.2时,首先激发磁共振模式;而长宽比大于2.2时,磁共振模式在第二个共振被激发;作为转折点,截面长宽比例约为2.2的电介质柱不能激发磁共振模式.结果还表明改变电磁波入射方向叮以调节长方形截面的电介质柱的磁共振发生的频率位置,实现偏振可控的电磁响应,这为新颖的电介质电磁超介质的设计与研究提供有价值的信息.
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