Dielectric Characteristics of Insulation Layers of Printed Circuit Boards at High Frequencies

Complex permittivities of various polymeric materials used as the insulation layers of printed circuit boards were measured in the frequency range from 1 MHz to 110 GHz using a newly developed dielectric measurement system and three commercial systems. The new system can measure the complex permittivity of rod-shaped lossy specimens, such as polyacetal, without reference materials. Experimental results reveal that the data measured by using the four different systems were in good agreement. The dielectric loss tandelta of most of the insulation layers was more than 0.01 at frequencies on the GHz order. This studies can contribute to clarifying the dielectric properties of materials used in printed circuit boards that affect the total loss of components as well as electromagnetic compatibility