Higher K low loss dielectric ceramic cofireable with a commercial LTCC tape system

The rapid growth in the application of LTCC technologies toward RF wireless circuit design is an important trend. This technology enables the cost effective integration of passive components into the LTCC platform. To support this application trend, Heraeus has studied higher permittivity and low loss dielectrics with NPO characteristic performance compatible with the Heraeus CT2000 low temperature co-fired ceramic tape system. Many commercially available microwave dielectrics have either too high a firing temperature, which make them incompatible with silver systems, or have high dielectric loss characteristics which limit their usage in RF wireless applications. This paper highlights a low loss and relatively high dielectric constant material from a bismuth based pyrochlore dielectric structure at microwave frequencies. Dielectric properties were measured in a frequency range of 10KHz to 4 GHz. This paper also addresses the physical and other electrical properties of these materials. The relationships between processing, microstructure, and electrical properties are discussed. This higher K and low loss dielectric along with compatible materials developed by Heraeus for this system will allow users to meet the challenges of reducing cost, and enhancing the performance of devices for microwave applications.