Design And Fabrication Of Edge Guided Mode Isolator

Ferrite isolators are indispensable in microwave communications, such as inter-stage isolation, realizing impedance matching, decoupling, and preventing inter harassment. With the development of microwave technology, devices are demanded to be miniaturization and wide band.In this paper, the distribution of electromagnetic fields of edge guided mode isolators were acquired, then, the basic designing parameters were obtained. The design of device included the structure of the isolator, the tapper line impedance matching section and the size of micro-strip line. Make use of three-dimensional electromagnetic simulation software Ansoft HFSS, suitable models of devices were designed. The ferrite materials were prepared with a traditional solid-state reaction and ion doping technology. On the basis of all of these achievements, we accomplished the preparation of different kinds of edge guided mode isolators.Edge guided mode isolator based on YIG was designed and prepared, YIG ferrite with low ferromagnetic resonance linewidth is gyromagnetic material and is suitable for low loss devices. The main technological character of device as follows. From 4GHz to 10 GHz, the measured minimum S12 was-1.7dB with S21 exceeding-20 dB, and the size of device is 25mm×13mm×0.65 mm.To achieving the purpose of reducing cost and the saturation magnetization of material, Al³⁺ doping technology was appropriate. The main technological character of device based on YAlIG as follows. From 2.5GHz to 5.5GHz, the measured minimum S12 was-2.5dB with S21 exceeding-20 dB, and the size of device is 50mm×20mm×1.6mm.In order to realize the goal of simplification and miniaturization without externally applied magnetic fields. Self biased edge guided mode isolator based on hexagonal ferrites was designed and prepared. M-type ferrite has a high saturation magnetization and magnetic anisotropy field, which is potential for millimeter wave applications and devices. The working frequency covered from 27.5 GHz to 29.5GHz, isolation was greater than 40 dB and insert loss was less than 10 dB, size of device is 10mm×7mm×1mm.