E‐band broadband digital controlled phase‐inverting variable gain amplifier in 65‐nm CMOS

Abstract

This letter reports an E‐band phase‐inverting variable gain amplifier in 65‐nm complementary metal‐oxide‐semiconductor (CMOS) technology. A fractional bit based structure with replica cells is proposed to minimise the phase error and ensure the tuning accuracy between different gain modes. This structure has 9‐bits digital‐controlled amplifiers and allows 180° phase shifting. The implemented phase‐inverting variable gain amplifier achieves 16 dB tuning range and 0.5 dB tuning step at 80 GHz. The root mean square (RMS) gain and phase errors across −3 dB bandwidth (i.e. 72–87 GHz) are less than 0.3 dB and 2.7°, respectively. The phase‐inverting variable gain amplifier consumes 8 mW at 1 V supply voltage.