Research On High Power And Low Loss Garnet Microwave Ferrite

A large number of transceiver components（T/R components）are required in 5G base stations and phased array radars.And circulators/isolators are required in each T/R component to achieve signal isolation,matching,and increase gain enhancement between microwave system antennas and transmitters.Garnet ferrire has the lowest ferromagnetic resonance linewidth（ΔH）and dielectric loss（tanδ_ε）compared to other ferrites,and it will be the first choice for applications in the X-band and below.Therefore,the research on high-power and low-loss garnet microwave ferrite materials has important academic value and application significance for the miniaturization and high-power design of microwave communication equipment.Firstly,the high-power characteristics of garnet ferrite were studied.By ion substitution on the dodecahedral position（24c position）of garnet ferrite,it was found that M³⁺(M=Gd³⁺,Dy³⁺,Ho³⁺)replacing Y_2.88-xM_xDy_0.02Ca_0.1In_0.3Ge_0.1Fe_4.6O₁₂ ferrite made theΔH_k of the material increase,at the same time theΔH of the material increase.Introducing vacancies by reducing the Gd³⁺content based on correct ratio promoted the progress of the solid-phase reaction.It reduced theΔH of the material but had little effect on theΔH_k of the material.The increasing of Gd³⁺content can effectively reduce the temperature coefficient of 4πM_s（α）of the material.In addition,the existence of vacancies increased the Curie temperature（T_c）of the material.Then,the low loss characteristics of garnet ferrite were studied.The substitution of In³⁺for Y_2.38Gd_0.5Dy_0.02Ca_0.1In_xGe_0.1Fe_4.9-xO₁₂ made the grain size increase and the 4πM_sandΔH of the material firstly decrease and then increase.Besides,it madeΔH_k gradually decrease.For Y_2.38-xGd_0.5Dy_0.02Ca_0.1+xZr_xGe_0.1Fe_4.9-xO₁₂ ferrite,the increasing of Zr⁴⁺substitution would make the grain size firstly decreased and then increased.Besides,it was found that 4πM_s increased,ΔH decreased,ΔH_k and resistivity（ρ）increased firstly and then decreased.When Ge⁴⁺replaced Y_2.48-xGd_0.5Dy_0.02Ca_xIn_0.3Ge_xFe_4.7-xO₁₂ ferrite,it was found that the grain size and 4πM_s gradually decreased,ΔH decreased firstly and then increased,ΔH_k increased,and the magnitude of tanδ_εremaind at 10^-4.For Y_2.48-2xGd_0.5Dy_0.02Ca_2xIn_0.3V_xFe_4.7-xO₁₂ ferrite,the increasing of the V⁵⁺substitution amount would make the grain size firstly decreased and then increased,4πM_s andρdecreased,ΔH fisyly increased and then decreased,andΔH_k was basically unchanged.But V⁵⁺substitution would increase tanδ_εand deteriorate the dielectric properties of the material.Finally,the preparation process of garnet ferrite was studied.When V₂O₅ was added as an additive to Y_2.48Gd_0.5Dy_0.02In_0.3Fe_4.7O₁₂,the 4πM_s of the material firstly decreased and then increased,butΔH andΔH_k firstly increased and then decreased.With the increasing of sintering temperature（T）,the grain size and 4πM_s of Y_2.33Gd_0.5Dy_0.02Ca_0.15In_0.3Ge_0.15Fe_4.55O₁₂ ferrite increased gradually.At the same time,itsΔH,ΔH_k andρdecreased.For Y_2.33Gd_0.5Dy_0.02Ca_0.15In_0.3Ge_0.15Fe_4.55O₁₂ ferrite,prolonging the holding time would make the grain size increase,the 4πM_s increased andρremain basically unchanged.