A Highly Linear Mixer-First Receiver Front-End with Automatic Gain Control

A 2-3 GHz mixer-first receiver front end is proposed for high linearity applications such as beamforming and multipleinput multiple-output (MIMO) arrays. The proposed architecture consists of an input matching network, a 4-path filter including a mixer and transimpedance amplifier (TIA), phase generation block, and a feed-forward automatic gain control (AGC) architecture formed by a peak detector and an analog-to-digital converter (ADC). The 65 nm bulk CMOS technology is used to simulate the performance of the system. An active-feedback TIA topology is used for baseband amplification, and an AGC loop is created to control transimpedance gain. This TIA topology achieves high linearity and low power dissipation. Finally, gain flexibility is obtained through the AGC loop.