Benzocyclobutene as Substrate Material for Planar Millimeter-Wave Structures: Dielectric Characterization and Application

The application of benzocyclobutene (BCB) polymer as dielectric substrate material for millimeter-wave microstrip structures is investigated in this paper to face the problem of large losses due to standard dielectrics in the high microwave range. Dielectric properties of BCB are characterized from S-parameter measurements on a conductor-backed coplanar waveguide (CBCPW) using the polymer as substrate material. Excellent features, with a low loss tangent and a stable dielectric constant, are demonstrated within the measurement range from 11 GHz to 65 GHz. As a validation of BCB high frequency performances, the design and experimental characterization of a V-band array on BCB substrate is presented. Measurement results on both matching and radiation characteristics of the millimeter-wave array are discussed.