Reconfigurable Receiver With Radio-Frequency Current-Mode Complex Signal Processing Supporting Carrier Aggregation

Abstract

A software-defined radio receiver that is suitable for intra-band carrier aggregation is demonstrated. The RF front-end frequency selectivity is enhanced by the combination of the passive mixer and a proposed reconfigurable transimpedance amplifier. High order bandpass filtering function with frequency notches can be achieved at the front-end. Current domain complex signal processing is explored to select and separate multiple channels concurrently. The receiver contains a variety of functional building blocks that can be connected in different ways to form various architectures. The fine-grained programmability of component parameters and reconfigurability of receiver schemes enable optimum performance under varying signal and blocker scenarios. A proof-of-concept CMOS chip fabricated in a 65 nm CMOS technology is presented that supports up to three-channel aggregation. The receiver operates at any frequency between 0.5 to 3 GHz. The frequency separation between the concurrent RF channels can be tuned anywhere between 0 to +100 MHz. The concurrent receiver scheme can also be explored to reject large near-band blockers for high dynamic range.