毫米波环行器平面化进展及自偏置六角铁氧体研究述评

Advances in planarization of millimeter wave circulator and a review of self-bias hexaferrites material

综合报道了最近国内外毫米波环行器的小型化、平面化进展,比较了自偏置及外场偏置微带环行器的性能,讨论了自偏置环行器插入损耗大的问题。回顾了近年来M型与W型六角铁氧体毫米波材料性能与离子代换的关系等研究动态;分析了微波频率下自偏置六角铁氧体的电磁损耗--铁磁共振线宽△H和介电损耗角正切tanδe的研究现状,讨论了BaM铁氧体△H的来源及进一步降低△H的途径--减小固相反应不完全致宽;阐明了减小器件插入损耗的关键在于降低非共振有效线宽△Heff,分析了BaM单晶较高△Heff产生的原因,提出了减小BaM多晶/单晶有效线宽的途径。最后讨论了有应用潜力的几种厚膜六角铁氧体制备工艺,包括液相外延、丝网印刷、低温共烧等。

The development of millimeter wave circulator in miniaturization and planarization is comprehensively reported and the problem of larger insertion loss of self-bias circulator is discussed. A review to the studies on properties of M-type and W-type hexaferrites with substitution of various ions for application in self-bias millimeter circulator, and their recent research trends and developments, are given. The research status in electromagnetic loss of the hexaferrites, i.e. the ferromagnetic resonance linewidth △H and the dielectric loss angular tangent tan δe, are analyzed. The source of linewidth of BaM and the way to further reduce △H by reducing the broadened △Hinc resulted from the incomplete solid-reaction, are also analyzed. It is pointed out that the key to reducing insertion loss is to reduce the effective linewidth in the non resonant zone △Heff, and the effective way to reduce the DHeff is mentioned. At last, several kinds of routines for prepareing hexagonal ferrite thick films with potential applications are introduced, including LPE, screen printing and LTCF.