The diversification of information and communication services has brought a variety of communication devices those incorporate radio communication circuits and require the circuit forming elements to be further microminiaturized and upgraded for higher radio frequency and broadband applications. In this trend, the key components are switching elements. Improving their performance is indispensable in order to realize next-generation information and communication services. RF MEMS technology, which combines 3-D micromachining technology and a high-frequency line design, is highly expected to provide a solution in this respect. The technology field has reached to a practical level and, in fact, a variety of key circuit elements are being proposed. In this paper, we propose a novel Single-Pole-Double-Throw (SPDT) RF MEMS switch design for RF signal applications in the 0.05-10GHz frequency. This new switch is actuated by electrostatic force and restoration force of spring for low power consumption. The Pyrex glass was used as base and cap substrates, and the single crystal silicon was used as movable parts. This device has extremely low insertion loss of -0.5 dB and a high isolation of -30 dB up to 10 GHz. The switch has compact dimensions of 2.8 x 4.8 x 0.9 mm with Chip Scale Package (CSP) structure. The packaging process with glass frit seal is applied to 4-inch processed wafer of RF MEMS switching devices.