The magnetic resonance frequency of SrFe₁₂O₁₉ hexaferrites is above 40 GHz due to a very high magnetic anisotropy. Therefore, they are not suitable as absorbing materials in the frequency range of 1–18 GHz. Doping with Zn and Ru (SrFe_12-2xZn_xRu_xO₁₉) decreases the magnetic anisotropy and can bring the resonance frequency below 18 GHz improving the microwave absorption in lower frequency band. Both the imaginary and real parts of the permittivity increase and the magnetic loss tangent has a wide peak for x ≥ 0.3, which is twice the dielectric loss tangent. Both of them contribute to the microwave absorption. For this level of doping, the microwave absorption is significant in a wide frequency range. For x = 0.5 and the sample layer of 1.7–4.8 mm thick, the absorption bandwidth (RL < −10 dB) is from 4.3 GHz to 18 GHz. For a single-layer of 1.9 mm, the absorption bandwidth is from 10.1 to 18 GHz. The broad absorption is due to tunable magnetic anisotropic field by the Zn and Ru doping. The detailed analysis also shows that the impedance matching plays an important role in improving the absorbing band.

由于非常高的磁各向异性，SrFe ₁₂ O ₁₉六铁氧体的磁共振频率高于40 GHz。因此，它们不适合作为 1-18 GHz 频率范围内的吸波材料。掺杂 Zn 和 Ru (SrFe _{12-2 x} Zn _x Ru _x O ₁₉ ) 可降低磁各向异性，并使谐振频率低于 18 GHz，从而改善低频段的微波吸收。介电常数的虚部和实部均增加，并且磁损耗正切对于x具有宽峰 ≥ 0.3，是介电损耗角正切的两倍。它们都有助于微波吸收。对于这种掺杂水平，微波吸收在很宽的频率范围内是显着的。对于x  = 0.5 和 1.7–4.8 mm 厚的样品层，吸收带宽 (RL < -10 dB) 为 4.3 GHz 到 18 GHz。对于 1.9 mm 的单层，吸收带宽为 10.1 至 18 GHz。广泛的吸收是由于 Zn 和 Ru 掺杂的可调谐磁各向异性场。详细分析还表明，阻抗匹配在改善吸收带方面起着重要作用。