A 148–170‐GHz 4‐bit variable gain amplifier with stagger‐tuning and multistage‐phase‐compensation techniques in 0.13‐μm SiGe.

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 0.165 mm2 $0.165 \,\text{mm}{}^{2}$. The results show the VGA achieves <4∘ $\lt {4}^{\circ }$ 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 <0.82 $\lt 0.82$ dB, the simulated input P1 dB ${P}_{1 \mathrm{dB}}$ is −10.5 $-10.5$ dBm and the total power consumption is 32.4‐mW with 2.25 V supply voltage. [ABSTRACT FROM AUTHOR]