A novel CMOS hexaferrite circulator with a Y-junction structure is designed and fabricated, which is compatible with standard CMOS technology. The spin-coating approach is adopted during the fabrication, in which the photoresist is mixed with nano-hexaferrite powder for preparation of a magnetic thin film in the device. Compared with the traditional circulator with an external permanent magnet for operation, the novel circulator can utilize the spin-coating magnetic film and is compatible with CMOS technology. The remanent magnetization of the adopted hexaferrite thin film can provide the required magnetic field for reciprocity properties. The optimization of impedance matching and the improvements in the related parameters are demonstrated on the novel CMOS circulator. The CMOS circulator exhibits the merits of small volume and easy integration while keeping its promising non-reciprocity properties. The fabrication is conducted based on the standard 180-nm CMOS technology. S-parameter measurements on the circulator show that the device has an isolation of 20 dB over 520 MHz bandwidth at 26.2 GHz. The minimum insertion loss is 1.81 dB. The novel CMOS-compatible circulator has potential application in 5G wireless communication systems.

中文翻译：

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具有25 GHz工作频率的新型CMOS六铁氧体循环器

设计并制造了一种新型的具有Y型结结构的CMOS六铁氧体环行器，它与标准CMOS技术兼容。在制造过程中采用旋涂法，其中将光致抗蚀剂与纳米六方铁氧体粉末混合以在装置中制备磁性薄膜。与使用外部永磁体进行操作的传统环行器相比，该新型环行器可以利用旋涂磁性膜，并且与CMOS技术兼容。所采用的六价铁氧体薄膜的剩余磁化强度可为互易性提供所需的磁场。在新型CMOS循环器上展示了阻抗匹配的优化和相关参数的改进。CMOS循环器具有体积小，易于集成的优点，同时又保留了其有前途的不可逆特性。该制造基于标准的180纳米CMOS技术进行。在循环器上进行的S参数测量表明，该器件在26.2 GHz的520 MHz带宽上具有20 dB的隔离度。最小插入损耗为1.81 dB。新型兼容CMOS的循环器在5G无线通信系统中具有潜在的应用。