Low-Loss 25 GHz RF Switches in 300 mm GaN-on-Si Technology with 0.4 dB Insertion Loss and 70 fs Ron×Coff

This work presents the design and experimental demonstration of 25 GHz RF switches in 300 mm GaN-on-Si technology for mm-wave applications through systematic gate length optimization and multi-throw architecture scaling. A comprehensive gate length study (50 nm to 250 nm) was conducted to optimize the fundamental active switch building block. Using the optimized design, SPDT and SP4T topology switches were implemented, and the fabricated switches achieve insertion losses of 0.4 dB, 0.74 dB, and 1.36 dB for SPST, SPDT and SP4T configurations, respectively, while showing isolation performance above 20 dB. These results successfully demonstrate a compact switch architecture that combines low loss, high isolation, and frequency-selective resonance, leveraging the inherent advantages of GaN MOSHEMT technology for high-frequency applications.