Miniaturization Substrate Integrated Rectangular Waveguide Ferrite Junction Circulator

The work of this thesis is addressed to the theoretical analysis and engineering implementation of the substrate integrated waveguide (SIRW) ferrite junction circulator. The conventional rectangular waveguide ferrite junction circulators take some advantages over other ferrite junction circulators, such as high Q quality, high power handling capacity etc. However, the drawback of the rectangular waveguide ferrite circulator lies in the integration difficulty with other planar circuits, which restrict its applications in HMIC and MMIC. In this work, the ferrite junction circulator is implemented in the form of SIRW, having the features of low profile, small volume and easy integration with other planar circuits. In this thesis, the basic characteristics of ferrite and the microwave propagation characteristic in ferrite are introduced firstly; the operational principle of the conventional rectangular waveguide ferrite circulator has been presented in succession. In addition, the equivalence characteristics of the SIRW with rectangular waveguide have been investigated. Furthermore, one C-band SIRW ferrite junction circulator has been designed, as well as the microstrip transition. One prototype of the SIRW ferrite junction circulator was fabricated to verify the validity of the design strategy. The measured results indicate good performances though a little frequency deviation was observed. It can be noted that the SIRW ferrite junction circulator and the microstrip line are constructed into a same substrate, demonstrating the high level of integration and prosperous applications in integrated communication and radar systems.