Design of RF Non-Reciprocal Device Using Ferrite in Microwave Integrated Circuits

A ferrite-based four-port circulator is designed using two three-port circulators to operate at ultra-high frequency 3 GHz – 5 GHz. A ferrite disk of 1.5 mm thickness and 13.5 mm in diameter is incorporated into the circulator design. The internal magnetic field of 1380 Oersteds and saturation magnetization (4$\pi$M) of 3900 Gauss is applied onto the ferrite disk for anticlockwise oriented magnetic field rotation. Maximum isolation of 27.6 dB and insertion loss of 23.1 dB is obtained at 3.5 GHz, which lies in the 5G band of communication. Further, the parametric study is conducted to observe the variation in characteristics of a circulator.