低温共烧陶瓷铁氧体环行器的设计与分析

基于叠层片式化结构对工作于S波段的低温共烧陶瓷(LTCC)铁氧体环行器进行设计和分析,模拟研究了器件制备中面临的关键问题对器件频率特性的影响。研究结果表明,采用微波铁氧体层与陶瓷介质层构成混合结构,匹配电路以三维方式进行布线和互联,器件可以获得优良的带内特性。在器件的三维电路布线中,当连接两节阻抗线的导体圆柱端口气隙高度达到20μm时,器件的传输特性和隔离特性急剧恶化。此外,研究还发现微波铁氧体层与陶瓷介质层出现分层时,形成的气隙高度不应大于20μm,否则将导致器件的传输特性和隔离特性显著降低。因此,在进行LTCC铁氧体环行器的制备时,导体圆柱与陶瓷介质层以及微波铁氧体层与陶瓷介质层的异质材料匹配共烧是保障器件优良性能的关键。

Design and analysis of low temperature co-fired ceramics ferrite circulator

The S-band low temperature co-fired ceramics (LTCC) ferrite circulator was designed and analyzed based on multilayer chip structure, and the effect of some key problems in the preparing process on the frequency characteristic of the LTCC ferrite circulator was investigated by simulation method. The results show that the LTCC ferrite circulator with hybrid structure, which consists of microwave ferrite layer, ceramic dielectric layer and three-dimensional matching circuit, can provide excellent in-band performance. The cylindrical conductor connects two impedance lines in the three-dimensional wiring circuit of the LTCC ferrite circulator. It is found that the transmission and isolation characteristics of the LTCC ferrite circulator deteriorate rapidly, when the height of port air gap under cylindrical conductor reaches 20 m. In order to resist the significant reduction of the transmission and isolation characteristics, the air gap between microwave ferrite layer and ceramic dielectric layer should not be more than 20 m. Consequently, the matching co-firing between cylindrical conductor and ceramic dielectric layer, and between microwave ferrite layer and ceramic dielectric layer is extremely important to ensure excellent performance of the prepared LTCC ferrite circulator.