Packaging approaches for GaN/Si SAW Band Pass Filters with Operating Frequencies above 5 GHz

This paper presents two packaging approaches for surface acoustic wave band pass filters (SAW-BPF) processed on GaN/Si and operating at frequencies above 5 GHz. One approach is based on a surface mount device (SMD) quad flat no-leads (QFN) ceramic package available off-the-shelf for applications up to few GHz. The other approach is based on quasi-wafer level packaging (quasi-WLP), using a PMMA cap and epoxy resin glue to cover only the sensitive area of the SAW-BPF. The two packages are evaluated using a coplanar waveguide transmission line (CPW-TL) as test vehicle. The ceramic SMD QFN package shows additional losses lower than 1 dB up to 6 GHz, while the PMMA quasi-WLP shows additional losses lower than 0.1 dB up to 30 GHz. SAW-BFPs with operating frequencies around 5.5 GHz are packaged using the two approaches and measurement data shows little effect on the main SAW-BPF parameters.