An Analog Wide-Bandwidth Baseband Chain for 12Gbps 256QAM Direct-Conversion Receiver

This paper presents a broadband low-power baseband designed for zero-IF phased-array receiver. It can support 12 Gbps 256QAM and 17Gbps 32QAM. Baseband circuit provides filtering for RF channel bandwidths of 1.4Ghz to 6Ghz in 16 different steps. It incorporates variable-gain-amplifiers with total tuning range of 40 dB. DC offsets up to +/-2.3mA at mixer output are cancelled. Baseband consumes 100mW per I and Q channel using double supplies of 1.5 V and 2.5 V. Design is fabricated in 0.18µm SiGe BiCMOS process with fT / fMAX of 240/270GHz.