基于高介电常数石榴石铁氧体的微带环行器设计

Design of microstrip circulator based on garnet ferrite with high dielectric constant

采用固相反应法制备高介电常数石榴石铁氧体材料。基于优化的材料性能,利用AnsysHFSS仿真软件对X波段微带环行器进行三维电磁场仿真分析,并结合微电子工艺进行实物研制。实验结果表明,高介石榴石铁氧体材料的介电常数为26,在9GHz附近材料的铁磁共振线宽为100Oe。器件仿真结果表明,在8~12GHz频率范围内,微带环行器的插入损耗小于0.4dB,隔离度大于20dB,电压驻波比小于1.2,表现出良好的环行特性。器件实物测试结果表明,在X波段内插入损耗小于1dB,隔离度大于18dB,驻波比小于1.25。造成实测性能变差的原因主要来自铁氧体较高的介电损耗,样品加工和测试过程产生的误差也有影响。相比于常规介电常数石榴石铁氧体材料研制的微带环行器,该环行器具有更小的体积和重量,实现了器件小型轻量化。

Garnet ferrite materials with high dielectric constant were prepared by solid-state reaction method.Based on the optimized material properties,the three-dimensional electromagnetic field simulation model of X-band microstrip circulator was optimized using the Ansys HFSS simulation software,and the physical development was carried out via microelectronic technology.The experimental results show that the dielectric constant of the garnet ferrite material is 26,and the ferromagnetic resonance linewidth of the material at about 9 GHz is 100 Oe.The simulation results show that in the range of 8 to 12 GHz,the insertion loss of the microstrip circulator is less than 0.4 dB,with the isolation greater than 20 dB,and the voltage standing wave ratio less than 1.2,showing a good circulator performance.The test results show that the insertion loss is less than 1 dB,with the isolation greater than 18 dB,and the voltage standing wave ratio less than 1.25 in the X-band.The deterioration of the measurement performance mostly derive from the high dielectric loss of the garnet ferrite,and the other reason is the error caused by the fabricating and testing process.Compared with the microstrip circulator developed by the conventional dielectric constant garnet ferrite material,the circulator sample has smaller volume and weight,realizing the miniaturization and light weight.