Design & Modeling of 6-Bit Low Loss Ka Band Distributed MEMS Phase Shifter on GaAs

This paper presents the design & modeling of distributed MEMS phase shifter for Ka band RF systems. The phase shift can be achieved by periodically placing the MEMS bridge variable capacitors as per Bragg frequency criteria on coplanar waveguide (CPW) using GaAs substrate. The EM & electromechanical simulation are carried out with various structural parameters to optimize the designs. The novelties like low insertion loss, low actuation voltage with distributed actuation pads & separate DC and RF are used to make the design unique. The EM simulations are carried out with HFSS and an insertion loss of -3.49 dB at 36GHz for a total Phase shift of 360 deg. was achieved with return loss of -20.6 dB over a frequency band 34-38 GHz. The electromechanical simulations are carried to achieve the low actuation voltage of 10.3V. The significance of this study is the realization of the digital phase shifter through DMTL approach.