Dual-Carrier Aggregation Receiver With Reconfigurable Front-End RF Signal Conditioning

Abstract

A reconfigurable receiver that can support dual-carrier aggregation is demonstrated. Switched Capacitor (SC) technique is explored at the receiver front-end for direct RF signal conditioning. By changing the connections of the switches and capacitors, various filtering profiles, including bandpass and notch functions, can be synthesized. On the other hand, complex-domain signal processing enables RF selectivity with controllable offset frequency relative to the LO frequency. Therefore, multiple RF channels can be selected simultaneously by multiple complex-domain signal processors and a shared single front-end. The scheme also enables a 4th-order RF bandpass transfer function by combining two 2nd-order bandpass transfer functions with slightly different center frequencies. In this work, a combination of a reconfigurable front-end passive SC network and two concurrent complex-domain signal processors enables the receiver to handle different signal scenarios. A proof-of-concept CMOS chip fabricated in a 65 nm CMOS technology is presented that supports single-channel and dual-carrier aggregation receiving modes. The receiver covers the frequency range from 0.1 to 1 GHz. The frequency distance between two concurrent RF channels can be tuned anywhere between 0 to +100 MHz. The near-band blocker resilience is improved by 15 dB when the front-end is configured as a notch filter.