Ka-Band Switchable Filter Bank with Silicon-Based Heterogeneous Integration

This paper presents a compact Ka-band filter bank based on heterogeneous integration, achieving dual-band operation at 24.25–27 GHz and 27–32 GHz. The design combines quartz glass filters with GaAs switches through 3D integration: GaAs chip-lets are embedded in a silicon interposer, and SU-8 redistribution layers provide high-density interconnects. The fabricated module occupies only 6.0 mm × 7.5 mm and exhibits less than 5 dB insertion loss across both bands. By synergizing low-loss quartz filters, high-power GaAs chip-lets, and packaging-compatible silicon interposers, this approach significantly enhances performance for multi-band 5G and satellite systems in the Ka-band.