A New Design of Dual Band Phase Shifter using MEMS Technology

This paper presents a new design of microwave microelectromechanical systems (MEMS) phase shifter for dual band wireless local area network (WLAN) applications. A bit is designed which produce a constant phase shift of 11.25° by switching between two lines that consist of 12 and 6 unitcells in each frequency band. A unitcell is constructed by gold membrane suspended over the coplanar waveguide (CPW) that can be moved vertically by electrostatic actuation. It can also ultimately be used for changing the operating frequency band. Two states of unitcell are used to switch between two frequency bands of 2.4 GHz and 5.2 GHz (IEEE 802.11 standard employed in dual band WLAN systems). First, a closed form equation of simplified model of the structure is obtained. Then, using this equation and advanced design system (ADS) simulator, the dual band phase shifter is designed. The validation of modeling and equations are demonstrated using the High Frequency Structure Simulator (HFSS). At the frequency of 2.4 GHz, maximum return and insertion losses are - 16.96 and -0.12 dB, respectively that exhibit a phase shift efficiency of 93.75 °/dB (60.22 °/cm). At the frequency of 5.2 GHz, maximum return and insertion loss are -16.86 and -0.15 dB, respectively exhibiting a phase shift efficiency of 75 °/dB (60.22 °/cm). The new proposed design is only to achieve a dual band phase shifter using MEMS technology which has low loss and weight with high linearity respect to the other technologies