用于自偏置微波环行器的W型六角铁氧性能研究

Self-bias play a key role in miniaturizing microwave devices. So far, self-biased gyromagnetic devices can’t be utilized well in a relative low range of microwave frequency. To meet this need, research on ions substitution of W-type hexaferrites have been started. The research is mainly studied on three fields listed as follows: synthesizing single-phase W-type hexaferrites, variation of materials’ properties along with ions substituion, crystalline grain textured along c-axis. Focusing on these area: ions substituted into different lattice sites and the impact on microstructure and magnetic properties of BaW, explore an approach to decline magnetocrystalline anisotropy field of material, realizing self-biased property of material and applicating at X-band or lower frequencies. Meanwhile,study on these fields, which contains influence of ions substitution on magnetic loss and dielectric loss of BaW, process of grain orientation in magnetic field to texture along c-axis, design and fabricate of self-biased microwave devices, would be started. Thus, synthesized BaW ferrite could be applicated on fabricate microwave devices, which is requested to be miniature, low loss and low frequency operative. Moreover, solving the problem of miniaturizing microwave gyomagnetic devices in new generation MMIC and system, promoting development of microwave system miniaturization.

自偏置是实现微波旋磁器件小型化的关键，针对目前自偏置旋磁器件不能满足低频应用的问题，以更易于离子取代改性的W型六角铁氧体为研究对象，主要对W型六角铁氧体的单相制备技术、离子取代对材料性能的调控规律、C轴取向织构化技术等方面展开研究。重点研究不同离子的取代与不同的取代类型对材料的结构与磁性尤其是磁晶各向异性的影响规律，寻求降低磁晶各向异性场的条件，使该材料不仅具备自偏置性能，而且能实现X波段或更低频段的应用。同时，研究离子取代对材料磁损耗与电损耗的影响机理，晶粒的磁场取向工艺对材料的C轴织构化的形成，自偏置微波旋磁器件的设计与制备进行研究，从而使材料满足自偏置微波旋磁器件的小型化、低损耗、低频化的发展要求。解决新一代微波单片集成电路与系统中微波旋磁器件的小型化问题，推动微波系统的小型化发展。

微波旋磁器件小型化的关键是自偏置，这样可去除外加磁体实现微波铁氧体器件如环行器/隔离器的平面小型化，单轴磁晶各向异性的W型六角铁氧体正是满足这一条件的潜在铁氧体材料。项目采用氧化物法制备工艺，结合湿法取向技术，研究了配方为Ba（ZnCo）2Fe16O27的W型六角铁氧体的单相制备，通过球磨时间、预烧温度、取向成型、烧结温度等方面的研究，在1300℃预烧下完成固相反应，二次球磨细化粉体到约1um以水为分散剂磁场取向成型，经过1100℃烧结得到了取向度为80%的单相W型铁氧体。研究了In3+离子取代对材料性能的影响的原理，即In3+的取代2b位六面体晶位中的Fe3+对于材料的磁晶各向异性大小影响机制，从而降低材料的磁晶各向异性内场，拓展其低频性能。采用HFSS软件设计仿真了基于W型自偏置铁氧体的微带结环行器，得到了优化的设计参数，完成了项目研究任务。