A Ka-Band Variable-Gain Phase Shifter With Multiple Vector Generators

A Ka-band variable-gain phase shifter (VGPS) using a multi-vector summation method is proposed, which represents both phase and amplitude by summing the I and Q signals of multiple vectors. The VGPS has an orthogonal phase and gain control function with a wide gain-control dynamic range because it is designed to keep the input and output impedances almost constant regardless of the control states. It shows a measured RMS phase error of 2.9 ° during 17.3 dB gain control and that of 3.5 ° during simultaneous 17.3 dB gain and 360 ° phase control without any calibration from 30 to 32.5 GHz. The measured average insertion loss ranges from -4 to -2.8 dB from 28 to 33 GHz. It is implemented in a 65-nm RF CMOS process with the size of 0.21 mm
²
excluding pads.