A Ka-Band True-Delay-Line Phase Shifter using Capacitive MEMS Switches

Themistoklis PRODROMAKIS¹, Christos PAPAVASSILIOU¹, Kostis MICHELAKIS<sup>2

1</sup>Circuits and Systems Group, Department of Electrical and Electronic Engineering
²Institute of Biomedical Engineering, Imperial College London, SW7 2AZ, UK
E-mail: [email protected], [email protected], [email protected]

Abstract. We present a monolithic, Si-based, 3-bit phaseshifter for the Ka-band. Our design is based on switched coplanar transmission line segments. Switching is implemented using 12 low insertion loss capacitive MEMS switches. The coplanar junctions (T-junctions) are designed such as phase variations due to switching uncertainties are avoided. Return loss of better than 10dB is reported over a 12.5% bandwidth while the insertion loss is less than 3dB. The proposed phase-shifter topology is capable of a very flat delay over a 35GHz to 45GHz bandwidth with 360º phase control at 45º intervals.