We propose a photonic crystal circulator based on quadrupole resonance of a magnetized ferrite cylinder. This device consists of a T-junction composed by three waveguides in a two-dimensional photonic crystal with square lattice. The ferrite cylinder is placed in the center of the T-junction. The scattering matrix, analytical model and the numerically calculated frequency characteristics of the circulator for the central frequency 94.5 GHz are presented. This device is compared with the previously suggested T-type circulator based on the dipole resonance mode. In particular, we show that the use of the quadrupole resonance permits to reduce the necessary DC magnetic field in comparison with dipole mode case by six times and this is important at THz frequencies where the necessary field is excessively high. Besides, quadrupole resonance requires the higher diameter of the ferrite resonator. The ferrite cylinders are produced by a special technology, and higher dimensions lead to a better reproducibility of such elements. However, these advantages are achieved at the expense of higher insertion losses and lower bandwidth of the circulator.

我们提出了一种基于磁化铁氧体圆柱体四极共振的光子晶体环行器。该器件由一个 T 型结组成，该 T 结由具有方形晶格的二维光子晶体中的三个波导组成。铁氧体圆柱体放置在 T 型接头的中心。给出了中心频率 94.5 GHz 的环行器的散射矩阵、解析模型和数值计算的频率特性。该设备与之前建议的基于偶极共振模式的 T 型环行器进行了比较。特别是，我们表明，与偶极模式情况相比，四极共振的使用允许将必要的直流磁场减少六倍，这在必要场过高的太赫兹频率下很重要。除了，四极共振需要更大直径的铁氧体共振器。铁氧体圆柱体采用特殊技术生产，尺寸越大，此类元件的重现性越好。然而，这些优势的实现是以较高的插入损耗和较低的环行器带宽为代价的。