A 3.7–43.7-GHz Low-Power Consumption Variable Gain Distributed Amplifier in 90-nm CMOS

A variable gain distributed amplifier (VGDA) for the Rx path of ultrawideband phased-array system is implemented in 90-nm CMOS process and presented in this letter. In order to achieve high gain and wideband with relative low dc power dissipation (P
_dc
), the combination of the conventional distributed amplifier (CDA) and the cascaded single-stage distributed amplifier (CSSDA) is utilized to the circuit. Moreover, the active variable termination resistor (AVTR) is adopted to adjust the flatness of gain. According to the experimental results, the proposed VGDA achieves a 21-dB peak gain with a 40-GHz 3-dB bandwidth (3.7-43.7 GHz), 18-dB gain control range (GCR), and 16° maximum phase variation.