A 110–145-GHz SiGe HBT D-Band Vector Modulator Phase Shifter Utilizing Differential Quadrature Delay Lines

This letter presents a 4-bit D-band SiGe vector modulator phase shifter (VMPS). A novel transmission line-based delay line topology is used to generate differential quadrature signals that are weighted by 4 variable gain amplifiers and cascaded with a buffer amplifier, achieving wide bandwidth, moderate gain, and low power consumption. The VMPS achieves 1.5-dB peak average gain with a 3-dB bandwidth from 110–145 GHz. The peak RMS amplitude and phase errors are 1.2 dB and 8.5°, respectively, and the circuit consumes 20.3 mW of average dc power from a 1.5-V supply. To the best of our knowledge, the presented D-Band VMPS achieves the widest fractional bandwidth of any mm-Wave VMPS implemented in silicon.