A SAW-less receiver front-end with continuously variable bandwidth and enhanced blocker-filtering

Abstract

A SAW-less receiver front-end with an active adjustable feedback loop for blocker-filtering is presented. By simply tuning the gain of loop amplifier, the −3 dB intermediate frequency (IF) bandwidth can be configured from 1 to 15 MHz continuously only using 46 pF capacitors. Moreover, the blocker current at low-noise amplifier (LNA) output can be effectively absorbed by the auxiliary capacitor and the loop amplifier buffer. The front-end operates from 0.1 to 2.5 GHz with maximal out-of-band rejection of 38 dB at 100 MHz offset frequency and it achieves 7-dBm out-of-band input third intercept point (IIP3). The design is implemented in 0.13 µm BiCMOS process.

The design of large image rejection and wideband CMOS active polyphase filter for BeiDou RF receiver

“…Currently, the low intermediate frequency (IF) quadrature down-conversion architecture [1,2,3,4,5,6] have been adopted as excellent RF receiver topologies to realize to highly integrated, high-performance, low-cost RF integrated circuits, such as the global navigation satellite systems (GNSS) RF receiver [7,8,9,10,11]. Image interferences has important effect on the final required signal-to-noise ratio (SNR) outputted to the baseband.…”