RF front-end with multistage stepdown filtering architecture

摘要

A radio-frequency (RF) front-end is described. In one embodiment, the RF front-end comprises a low noise amplifier (LNA), a first mixer and an I/Q quadrature mixer. The LNA amplifies a received signal at a carrier frequency, the LNA having inductive loads. The first mixer is coupled to the low noise amplifier and mixes an amplified received signal with a first local oscillator (LO) signal to down convert the amplified received signal to an intermediate frequency (IF). The first mixer has inductive loads. The first frequency is related to the carrier frequency such that an image channel associated with the carrier and the LO frequency is outside the bandwidth of the inductive loads of the LNA. The I/Q quadrature mixer stage has a second mixer and a third mixer coupled to the first mixer. The I/Q quadrature mixer converts the amplified received signal at the IF to I and Q signals using a second LO signal related to the first LO signal.