Hexagonal Nano-ferrites used on a V-band Self-bias On-chip Circulator for CMOS

In this work, we present the design, simulation, fabrication and measured results of a self-bias micro-strip line Barium hexagonal Nano-ferrite (BaM) circulator on silicon wafer. This planar Y-junction circulator is 2 mm by 2 mm by 0.5 mm in size, which is capable of future integration with the top three layers of 180 nm CMOS technology. Ferrite thin film is deposited and patterned employing composite spin-casting method. Typical characterization techniques are employed together with free-space quasi-optical spectrometry to study complex permittivity and permeability of deposited film up to 120 GHz. S parameters of fabricated circulators are characterized by a set of on wafer probes up to 67 GHz. We observed over 15 dB non-reciprocal phenomenon at 55 GHz.