Analysis Technique for Transmission Loss of Microstrip Lines at Millimeter-Wave Band

Abstract

To use millimeter-wave transmission efficiently, it is necessary to reduce transmission line losses. Thus, a dielectric substrate having a low dielectric constant and copper foil having a low roughness are used to create a copper-clad laminate (CCL). The physical properties of dielectrics and conductors for use in circuit design, such as dielectric properties and surface resistance, are measured independently. On the other hand, since an actual circuit is formed through various processes, the designed transmission characteristics are not always obtained. In this study, I propose a method to analyze the cause of the losses in millimeter-wave transmissions by separating the losses into dielectric losses and conductor losses for a microstrip line circuit actually fabricated from CCL. As a result, it was confirmed that the losses can be estimated based on the characteristics of the dielectrics and copper foils.