A Study of Very Low MM-Scale DK Variation Fluoro-Carbon Resin Substrate on MM-Wave Range

Recently fluoro-carbon resin substrates are numerously used for mm-wave application especially such as radar systems for vehicles. These application is operated in 70-80GHz frequency band but generally specified dielectric constant (Dk) is standardized only in 10GHz band. Radar designers need actual Dk on 70- 80GHz, so some methodological approaches to measure mm-wave range Dk values have been researched. However, these conventional approaches were able only to measure averaged Dk, because they used relatively large sized resonator involving large area dielectric substrate. In actual mm-wave antenna design, mm-scale element allocation must be required. That's why Dk value for mm-scale on mm-wave range is important. We have developed mm-scale resonator pattern with mm-wave probes, we achieved very low mm-scale Dk variation on mm-wave range with some substrate configuration of fluoro-carbon resin with thinner open-bundled glass fabrics and comparing to conventional one.