135GHz antenna array on BCB membrane backed by polymer-filled cavity

A 2×2 co-planar patch array on benzocyclobutene (BCB) membrane backed by low-loss polymer-filled cavities is designed and verified by measurement at 135GHz. The backing cavity is designed to enhance the antenna gain as well as to provide mechanical stability of the structure. The array is verified by measurement in a submillimeter-wave chamber with an achieved impedance bandwidth of up to 17 GHz (125-142 GHz) for |S₁₁| ≤ -10 dB and gain of 10.4 dBi at 135 GHz. The antenna array on Si/BCB is compatible with through-silicon via (TSV) based technique for 3D packaging system. The design is low profile yet still provides much higher gain performance when compared to antennas fabricated directly onto silicon substrate.