High Power Ferrite Phase Shifter for Beam Steering Applications

Current electronic beam steering applications require the design of high power differential phase shift sections with increased bandwidth and optimum operational efficiency. At high power levels nonlinear loss is prevalent but this can be avoided using a technique called 'mode segregation' by biasing the ferrite above ferrimagnetic resonance. A combined magnetostatic/microwave finite element scheme is used to model this mode of operation in a high power partial height differential phase shifter. Commencing from the non-linear magnetisation curve and magnetic circuit geometry, the magnetic state of the ferrite is evaluated as a prerequisite to calculating the full microwave solution. The above resonance operation avoids nonlinear loss but at the cost of reduced differential phase shift and larger external magnetic bias fields. The calculations agree well with the experimental data.