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This letter presents a D‐band 5‐bit vector‐modulated phase shifter based on quadrature hybrids for D‐band phased arrays. The proposed vector‐modulated phase shifter employs two stages of quadrature hybrid followed with a single‐pole double‐throw switch for I/Q phase splitting and vector‐summing. To improve the isolation performance, traveling‐wave single‐pole double‐throw switches together with transistor parallel inductors are adopted. A marchand balun followed with two variable gain amplifiers is placed between the two quadrature hybrids for I/Q amplitude weighting. A proof‐of‐concept vector‐modulated phase shifter is designed and fabricated in 0.13 μm SiGe BiCMOS technology and occupies a core chip area of 0.45 mm2. Measurement results show that the RMS phase error is 1.6° at 149 GHz and the RMS gain error is below 2.8 dB over 146–156 GHz. The DC power consumption is 148 mW.

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This letter presents a 148–170‐GHz 4‐bit variable gain amplifier (VGA) with stagger‐tuning and multistage‐phase‐compensation techniques. In the design of this proposed VGA, phase variation is minimized by cascading overcompensation VGA and undercompensation VGA with reverse gain‐phase characteristics and phase suppression characteristics at sideband, achieved through different shunt inductors to ground. Additionally, stagger‐tuning technique has been introduced to realize VGA design. To prove these techniques, a 148–170‐GHz 4‐bit VGA has been fabricated in 0.13‐μm SiGe bipolar complementary metal‐oxide‐semiconductor (350/450 GHz ft/fmax) with a compact size of . The results show the VGA achieves phase variation and over 10‐dB tuning range with 0.6‐dB gain step for a wide operating frequency from 148 to 170 GHz. The RMS gain error is  dB, the simulated input is  dBm and the total power consumption is 32.4‐mW with 2.25 V supply voltage.