A radio frequency (RF) microelectromechanical systems (MEMS) switch is manufactured by independent processing and subsequent bonding together of a MEMS substrate in alignment with an RF substrate. The RF MEMS switch is designed so as to encapsulate a flexing diaphragm supporting a switch electrode used with electrostatic flexing potentials to move electrodes of the MEMS substrate up and down over an RF transmission line structure of the RF substrate. The bonded combined MEMS switch structure is used to create an encapsulated RF MEMS switch suitable for direct coupling, AC coupling, and direct modulation of RF signals. The resulting MEMS RF switch device provides a reliable, minimally distorting RF transmission line geometry, free of contamination for use in high speed RF signal switching applications well suited for advance communication RF switching requirements.