LiZn铁氧体及其在Ka波段移相器中的应用研究

发布时间：2019-04-29 07:28

【摘要】：移相器是一种能够对电磁波的相位进行调整的微波器件,广泛地应用于雷达系统、微波通信系统和测量系统等军用以及民用工程系统中。移相器有多种类型,其中铁氧体移相器由于具有插入损耗小、功率容量高、工艺成熟以及价格低廉等特点而得到广泛的应用。本文研究了适用于Ka波段铁氧体移相器的LiZn铁氧体,并以此为磁心材料,研究设计了Ka波段用背脊式波导非互易锁式铁氧体移相器。首先,研制了具有高饱和磁化强度(Bs)和高剩余磁化强度(Br)、高矩形比(Br/Bs)和低矫顽力(Hc)等特性的LiZn铁氧体。主要研究了添加剂Bi2O3和烧结温度对LiZn铁氧体性能的影响,并得知Bi2O3添加量为1wt%以及烧结温度为980℃时,能较好地兼顾LiZn铁氧体材料的矫顽力、饱和磁化强度、剩余磁化强度和矩形比的目标要求。研制了Bs420mT,Br370mT,Hc120A·m-1和Br/Bs0.85的LiZn铁氧体旋磁材料。其次,采用电磁仿真软件Ansoft HFSS 12.0对移相器在33.5~34.5GHz频率范围内进行电磁仿真设计,研究了移相器结构对移相器性能的影响。结果表明:增大铁氧体矩形环的壁厚、使用高介电常的填充介质和缩小铁氧体磁心孔的宽度会提高铁氧体移相器的差相移;另外,增大背脊波导的背脊高度,差相移也会增大,但会恶化移相器相移量的频率响应特性。优化了移相器的结构尺寸,仿真结果表明:在33.5~34.5GHz范围内,铁氧体矩形环为20mm时,移相器插入损耗绝对值小于0.91dB,电压驻波比小于1.08,在34GHz处相移量达到276°。最后,研究了移相器的装配技术与移相器驱动系统,并利用矢量网络分析仪对移相器实物进行测试。测试结果表明,在室温下,33.5~34.5GHz频段内,长度为20mm的1号移相器,驻波比小于1.4,插入损耗绝对值小于1.05dB,在中心频率点34GHz处的相移量为149°;长度为20mm的2号移相器,驻波比小于1.4,插入损耗绝对值小于1.6dB,在34GHz处的差相移为146°;由1号和2号移相器连接而成的3号双节移相器,电压驻波比小于1.5,插入损耗绝对值小于2.3dB,在34GHz处的相移量为293°。随后分析了实测结果与仿真结果产生巨大差别的原因。
[Abstract]:Phase shifter is a kind of microwave device which can adjust the phase of electromagnetic wave. It is widely used in radar system, microwave communication system, measurement system and other military and civil engineering systems. There are many types of phase shifter, among which ferrite phase shifter has been widely used because of its low insertion loss, high power capacity, mature process and low price. In this paper, the LiZn ferrite suitable for Ka-band ferrite phase shifter is studied, and the back-ridge waveguide non-reciprocal lock ferrite phase shifter for Ka band is designed with the LiZn ferrite phase shifter as magnetic core material. Firstly, LiZn ferrites with high saturation magnetization (Bs), high residual magnetization (Br), high rectangular ratio (Br/Bs) and low coercive force (Hc) were prepared. The effects of additive Bi2O3 and sintering temperature on the properties of LiZn ferrite were studied. It was found that the coercive force and saturation magnetization of LiZn ferrite could be taken into account when the content of Bi2O3 was 1wt% and the sintering temperature was 980 鈩，

本文编号：2468064