Composite materials made of micron-sized oxide particle fillers in an epoxy resin matrix that can be molded into desired shapes are widely used for packaging radiofrequency and microwave-integrated circuits (ICs). To potentially employ these materials with millimeter-wave ICs (MMICs), quantitative knowledge of the composites’ dielectric properties across a broad millimeter-wave band is necessary. Here, we present non-destructive measurements of the complex relative permittivity, ε_r = ε′ + jε″, on some possible MMIC packaging composites consisting of silica and/or alumina microsphere fillers dispersed in an epoxy matrix. Measurements using phase-sensitive transmission over the WR3 and WR5 frequency bands (140 to 325 GHz) show that ε′ ranged from 3.6 for pure silica filler to 7.2 for pure alumina filler, with very little frequency dispersion. In all materials, the loss tangent tanδ = ε″/ε′ was between 0.01 and 0.02 in this frequency range. An analysis using the theory of two-component composites is used to extract the real permittivity of the epoxy resin. The results could be used to model performance of packaged MMICs and to design composites having a tailored value of ε′.

由微米尺寸的氧化物颗粒填料在环氧树脂基体中制成的复合材料可以模制成所需的形状，被广泛用于封装射频和微波集成电路（IC）。为了潜在地将这些材料与毫米波IC（MMIC）一起使用，必须对复合材料在宽毫米波带上的介电性能进行定量了解。这里，复相对介电常数，我们本非破坏性测量ε _{- [R}  =  ε '+  jε “，在由二氧化硅和/或分散在环氧树脂基体的氧化铝微球填料的一些可能的MMIC封装复合材料。在WR3和WR5频段（140至325 GHz）上使用相敏传输进行的测量表明，ε'的范围从纯二氧化硅填料的3.6到纯氧化铝填料的7.2，几乎没有频率分散。在所有材料中，损耗角正切δ  =  ε “/ ε '在这个频率范围为0.01和0.02之间。使用两组分复合物的理论进行分析，以提取环氧树脂的实际介电常数。结果可用于对封装的MMIC的性能进行建模，并设计具有定制值ε的复合材料。