135-GHz co-planar patch array on BCB/silicon with polymer-filled cavity

This work presents a co-planar patch array on silicon/benzocyclobutene (BCB) with polymer-filled cavities operating at 135 GHz. Backed by a polymer-filled cavity, a single co-planar patch can achieve gain enhancement of 2 dB. The presence of the polymer in the cavity also improves the mechanical stability of the overall structure. The measured impedance bandwidth reaches up to 18 GHz and 17 GHz for |S₁₁| ≤ -10 dB at 135 GHz band for a single element and a 2×2 antenna array, respectively. The gain for the 2×2 array is 11.5 dBi. The antenna is desirable for wafer level packaging due to simplicity, low profile and higher gain performance as compared to antennas fabricated directly onto silicon substrate.