Design of Ka-band Five-bit Distributed MEMS Transmission Line Phase Shifter

The distributed MEMS phase shifters are achieved by periodically loading distributed capacitors on a coplanar waveguid.The capacitance of the MEMS capacitors is contolled by the driving voltage.The overall structure of the 5-bit distributed MEMS phase shifter is presented,and the design methods of theoretical parameters are analyzed.Software HFSS is applied to built and simulate the three-dimensional model of single MEMS bridge section,and simulation results of the S paraments are used to determine the precise structural parameters of MEMS bridge under the up state and down state.The microwave equivalent circuit of the phase shifter is established with software ADS.Simulation results show that the phase error and the insertion loss of the phase shifter are less than 0.6° and 0.3 dB,respectively,and its return loss is more than 25 dB at 35 GHz.