Thin, non-conductive electromagnetic interference shielding materials with high absorption efficiency and temperature stability in the UHF band are still in demand. Therefore, we propose a single-step synthesis method of NiZnFeO core-shell nanoflowers (NFs) with high shielding efficiency (SE) and reflection losses (RL). NiZnFeO NFs comprise an oxidized shell and spinel core, providing high magnetic and dielectric losses. The attenuation constant was high and increased slightly with temperature from 329 to 340 Np/m (at 2.1 GHz). Also, temperature-induced changes in SE and RL were negligible. The analysis confirmed the applicability potential in the UHF band. For example, at 1.2 GHz, an SE equal to -13.53 dB can be achieved for 3 mm and -38 dB at 2 GHz for 4 mm absorber thickness. Moreover, increasing the thickness to 5.73 mm shifts the absorption range even to 0.88 GHz, while 2 mm absorbers can be used above 2 GHz.

中文翻译：

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NiZnFe2O4核壳纳米花作为有效的EMI屏蔽材料，致力于吸收UHF频段和宽温度范围内的电磁波

仍然需要在 UHF 频段具有高吸收效率和温度稳定性的薄型、非导电电磁干扰屏蔽材料。因此，我们提出了一种具有高屏蔽效率（SE）和反射损耗（RL）的NiZnFeO核壳纳米花（NF）的一步合成方法。NiZnFeO NF 包含氧化壳和尖晶石核，具有高磁损耗和介电损耗。衰减常数很高，并且随着温度从 329 Np/m 略微增加到 340 Np/m（2.1 GHz 时）。此外，温度引起的 SE 和 RL 变化可以忽略不计。分析证实了 UHF 频段的适用潜力。例如，在 1.2 GHz 时，对于 3 mm 的吸收体厚度，可以实现等于 -13.53 dB 的 SE；在 2 GHz 下，对于 4 mm 的吸收体厚度，可以实现等于 -38 dB 的 SE。此外，将厚度增加到 5.73 mm 甚至可以将吸收范围移动到 0.88 GHz，而 2 mm 吸收器可以在 2 GHz 以上使用。