Wafer Level Packaging of GaN/Si SAW Band Pass Filters with Operating Frequencies Above 5 GHz

This paper proposes a quasi-wafer level packaging approach of surface acoustic wave band pass filters (SAW-BPF) with operating frequencies above 5 GHz. A Poly(methyl methacrylate) (PMMA) cap is designed, fabricated and glued using an epoxy resin directly on the GaN/Si chip. First a coplanar waveguide transmission line is packaged and measured up to 65 GHz. Results show additional insertion losses of only 0.1 dB up to millimeter wave frequencies. A 5.6 GHz SAW-BPF is then packaged using the same approach. Measurement results show excellent properties of the packaged device for a temperature range between −150 … + 150°C.