35 GHz Analog Phase Shifter Based on Push–Pull Toggle MEMS Varactor

F. SOLAZZI¹, P. FARINELLI², B. MARGESIN¹, R. SORRENTINO<sup>3

1</sup>MemSRaD Group, Fondazione Bruno Kessler (FBK), Via Sommarive 18, 38050 Trento, Italy
²RF Microtech, Via G. Duranti, 93, 06125, Perugia, Italy
³University of Perugia, Dept. of Electronic and Information Engineering, Via G. Duranti, 93, Italy

Abstract. This paper presents the design of two 35 GHz analog MEMS phase shifters to be integrated in reconfigurable reflectarrays. The proposed devices consist of distributed MEMS transmission lines (DMTL) periodically loaded by shunt highly – tunable MEMS varactors. The MEMS varactor exploits a torsion spring anchoring to provide a toggle push – pull mechanism, which allows the device to have a virtually full travel range. A toggle varactor prototype has been electromechanically modeled and manufactured at FBK. The electromagnetic model has also been developed on the basis of the varactor’s measured response and the fitted capacitance values have been used for the design of the phase shifter unit cell. RF full–wave simulations of the phase shifters are presented showing very high RF performance as well as small space occupation allowing their integration in electronically steerable reflectarrays.
Index Terms. Toggle, MEMS Varactor, DMTL, Reflectarray.