A Compact RF MEMS Metal-Contact Switch and Switching Networks

A compact RF MEMS metal-contact switch based on a tethered cantilever topology and orthogonal anchors is presented. The switch is a “medium-force” design capable of achieving a simulated contact force of 0.38–0.72 mN for actuation voltages of 90–100 V and a simulated restoring force of 0.46 mN in a 120 $,\times,$ 160 $\mu {\rm m}^{2}$ area. The pull-in and release voltages are 75 V and 70 V, respectively. In the down-state position, the switch resistance is 1–2 $\Omega$ with a Au/Ru hybrid contact. In the up-state, the capacitance is 16 fF, resulting in an isolation of 20 dB at 10 GHz and 9 dB at 40 GHz for an SPST configuration. For a series/shunt configuration, the switch achieves an isolation of 55 dB at 10 GHz and 35 dB at 40 GHz. Compact SP4T and SP6T switching networks are also implemented. The SP4T is 850 $,\times,$ 530 $\mu {\rm m}^{2}$ (850 $,\times,$ 650 $\mu {\rm m}^{2}$ with bias pads); the SP6T is 850 $,\times,$ 730 $\mu {\rm m}^{2}$ (850 $,\times,$ 855 $\mu {\rm m}^{2}$ with bias pads). Both designs achieve an isolation of $\sim 36~{\rm dB}$ and an insertion loss of $< 0.3 ~- \rm dB}$ at 3 GHz.