微波铁氧体介电常数测量值的尺寸因素修正

用普通陶瓷工艺制备了饱和磁化强度M_s为96 kA/m的钇钙钒石榴石铁氧体材料,在10.7 GHz下按照GB9633(等同IEC60556标准)测量了石榴石铁氧体的介电常数ε'及介电损耗tanδ_ε。实验表明测得的ε'值随试样直径的减小而降低。由计算公式分析了ε'随试样直径减小而降低的原因。给出了ε'测量值与试样直径关系的经验公式及ε'的尺寸修正系数,修正以后可以基本上消除ε'测量值中由试样尺寸引起的误差。最后讨论了介电常数和介电损耗的精准测量问题。

Correction of specimen's dimension to the measured value of dielectric constant for microwave ferrites

Polycrystalline YCaVIGs garnet materials with saturation magnetization of 96kA/m were prepared by conventional ceramic process. According to the National Standard GB9633( equal to IEC 60556 standard ) for gyro-magnetic materials, the dielectric constant ε' and the dielectric loss angle tangent tan δεwere measured at 10.7 GHz for garnet specimens with different diameters. The results show that with decreasing samples' diameter the ε' value decreases. This result is discussed with the ε' calculating equation. To correct the calculation deviation of the measured dielectric constant ε' value, a dimension correction-coefficient and an experimental equation about the dimension dependence of the ε' value were proposed. Using the dimension correction equation, the error of the measured ε' value can be corrected basically. The problem of the measurement of dielectric constant and dielectric loss with more accurate was discussed.