Microwave Monolithic Devices Using Magnetic Hard-Soft Nanocomposite

Microwave magnetic devices have a major impact on the development of microwave technology. Ferromagnetic soft and hard ferrites are of special interest in order to make these devices. We have synthesized hard-soft nanocomposites of ferrites using barium hexaferrite (BaM)/yttrium iron garnets (YIG) at different ratios using the hydrothermal technique. The composites are deposited on a coplanar waveguide (CPW) by a medium-voltage electrophoresis method. The CPW devices are then tested for their notch-filter and phase shifter characteristics. The band-reject filter's response over a wide frequency range and with applied magnetic fields (H) from 0 to 12 kOe was investigated. The attenuation increases with the increase in operating frequency having a tuning range: 1-30 GHz, bandwidth at 15 dB: 3.2 GHz and frequency tunability: 2.37 GHz/kOe. For phase shifter, the influence of magnetic material was studied for two frequency regions (at 9 and 30 GHz) one below and another above ferromagnetic resonance. In the high-frequency region (at 30 GHz), the optimal differential phase shift increased to 40 degrees/cm for 0.5BaM/0.5YIG-based phase shifter at the highest field value.