Overview

Microwave circuits are popularly formed on multi-layered organic or non-organic substrates. In the microwave circuits, the attenuation of planar transmission lines such as striplines, microstrip lines, and coplanar lines are determined by their conductor loss, dielectric loss and radiation loss. Among them, the conductor loss is a major factor in the attenuation of the planar transmission lines. A new measurement method is standardized in this document to evaluate the conductivity of transmission line on or in the substrates such as the organic, ceramic and LTCC (low temperature co-fired ceramics) substrates. This standard describes a measurement method for resistance and effective conductivity at the interface between conductor layer and dielectric substrate, which are called interface resistance and interface conductivity. IEC 61338-1-3 describes the measurement procedure for the surface resistance and the effective conductivity on the conductor surface. The conductivity is referred to as surface conductivity in this standard. This standard describes a method for measuring the resistance and effective conductivity at the interface between the conductor layer and the dielectric substrate, respectively referred to as interfacial resistance and interfacial conductivity. In transmission lines in the substrates the electric current is concentrated at the interface between the conductor layer and the dielectric substrate because the depth of penetration into the conductor at microwave frequencies is in the µm range. In microstrip lines the electric current concentrates at the interface rather than at the outer surface of the conductor. In addition, the interfacial side of the copper foil in copper-clad organic substrate materials has a rough structure to ensure good adhesion. In LTCC substrates the interface between the conductor and the ceramic has a rough structure, depending on the co-fire process and the material composition. The conductor losses depend on the interface conditions. IEC 61338 with the general title "Waveguide type dielectric resonators" comprises the following parts: - Part 1: Generic specification - Part 1-3: General information and test conditions - Measurement method of complex relative permittivity for dielectric resonator materials at microwave frequency - Part 1-4: General information and test conditions - Measurement method of complex relative permittivity for dielectric resonator materials at millimeter-wave frequency - Part 2: Guidelines for oscillator and filter applications - Part 4: Sectional specification - Part 4-1: Blank detail specification. The responsible committee is DKE/K 642 "Piezoelektrische Bauteile zur Frequenzstabilisierung und -selektion" ("Piezoelectric and dielectric devices for frequency control and selection") of the DKE (German Commission for Electrical, Electronic and Information Technologies) at DIN and VDE.

Document: references other documents

Responsible national committee

DKE/K 642 - Piezoelektrische Bauteile zur Frequenzstabilisierung und -selektion