A compact high-isolation DC-50 GHz SP4T RF MEMS switch

This paper presents a compact high isolation SP4T series/shunt RF MEMS switch based on a four-pole radial series switch and miniature shunt switches in every arm, all in an area of 860 × 880 μm², including the CPW port transmission lines. The SP4T series switch achieves a simulated contact force of 0.37-0.56 mN for an actuation voltage of 70-80 V. The miniature shunt switches achieve a simulated contact force of ~0.1 mN for an actuation voltage of 90 V. The SP4T switch achieves an isolation of 60-32 dB and an insertion loss of 1-2 dB at 8-50 GHz. The switching time is 4-6 μs at 80 V operation. A cold-switched reliability of better than 10⁸ cycles with an RF power of 100 mW and 300 mW has been achieved. The application areas are in wideband TTD phase shifters and X/Ku/Ka-band and V-band switching networks. To our knowledge, this represents the highest isolation wideband SP4T switch achieved to-date, and with excellent impedance match at all ports.