A tunable 140GHz analog phase shifter with high linearity performance

An analog phase shifter for applications around 140GHz is presented. The MMIC is based on our in-house 100nm InGaAs mHEMT technology and has a chip size of 1mm 2. The circuit uses two quarter-wavelength transmission lines and two tunable impedances governed by a control voltage. As a result, the signal phase can be controlled stepless with a maximum shift of about 60°. Over the whole tuning range the gain ripple is less than 0.3dB and the phase shifter has a conversion gain of about -3.5dB. Because of its passive topology the circuit shows a very high linearity.