Ka波段自偏置微带环行器优化设计与仿真分析

Optimal design and simulation of Ka-band self-biased microstrip circulator

基于BaM型六角铁氧体材料,利用有限元仿真软件建立微带环行器的三维电磁场模型,优化仿真设计Ka波段自偏置环行器的结构和尺寸,探究铁氧体基板厚度h、中心圆盘半径R_(0)以及大小Y结尺寸对环行器性能的影响。结果表明,在26~28GHz频率范围内,插入损耗S_(21)随着铁氧体基板厚度h增大而增大,隔离度S_(12)和回波损耗S_(11)随铁氧体基板厚度h和中心圆盘半径R_(0)先增大后减小;随着大小Y结长度和宽度的增大,回波损耗S_(11)和隔离度S_(12)均先增大后减小。经优化仿真后,在26~27.6GHz频率范围内,环行器插入损耗S_(21)均小于1dB,最小插入损耗为0.85dB,最大隔离度为53dB,隔离度S_(12)和回波损耗S_(11)均大于20dB的带宽约1.6GHz,器件整体尺寸为7mm×7 mm×0.4mm,具有良好的环行性能。

Based on BaM-type hexagonal ferrite material,the three-dimensional electromagnetic field model of the microstrip circulator was established by using the finite element simulation software.The structure and size of the Ka-band self-biased circulator were optimized and designed.The effects of the thickness of the ferrite substrate h,radius of the central disc R_(0) and size of the Y-junction on the performance of the circulator were investigated.The results show that in the frequency range of 26 to 28 GHz,the insertion loss S_(21) increases with the increase in the thickness of the ferrite substrate(h),while the isolation S_(12) and the return loss S_(11) increase first and then decrease with the thickness of the ferrite substrate and the radius of the central disk(R_(0)).With the increase in the length and width of the Y-junction,the return loss S_(11) and the isolation S_(12) increase first and then decrease.After optimization and simulation,in the frequency range of 26 to 27.6 GHz,the insertion loss S_(21) of the circulator is less than 1 dB,the minimum insertion loss is 0.85 dB,and the maximum isolation is 53 dB.The bandwidth is about 1.6 GHz when the isolation S12 and the return loss S_(11) are greater than 20 dB,and the profile dimension of the device is 7 mm×7 mm×0.4 mm,which has good circular performance.