Development of a double-pole double-throw radio frequency micro electro-mechanical systems switch using an ‘S’ shaped pivot

Abstract

This paper investigates the design of a novel pivot for a seesaw, RF MEMS, double-pole double-throw (DPDT) switch, which has been developed to operate within mobile communication systems and devices. The pivot employs a unique ‘S’ structure at the nano scale, in the form of a, which helps to keep von-Mises stresses below 21 MPa. The pivot requires less pulling force than similar designs due to its flexibility which allows the beam and contacts a greater space of separation while the switch is off. This in turn results in improved contact isolation of greater than −77 dB at 5 GHz. The RF MEMS switch is an improvement over the previously published paper (Al-Amin et al. in International symposium on microelectronics, vol 2013, no 1, pp 000831–000835, 2013. doi:10.1109/ECS.2014.6892558), since the pulling force of the electrostatic plates can be generated with a voltage which is greatly reduced from 14 to 8 V using the same electrostatic plate area size. The switch is a progression from SPST and DPDT seesaw switching since it provides improved flexibility over the previously described devices. With the redesign of the pivot the switch attains a greater ‘air-gap’ between the contacts when open-circuited which therefore allows for improved isolation during the off-state.