Demonstration of Receiver-Noise/Distortion Shaping in Antenna Arrays by Using a Spatio-Temporal Δ-Σ Method

The spacetime-causality light-cone concept has been well-known since being introduced in Einstein's Special Theory of Relativity, but it has not been explicitly explored in antennaarray electronics. To date, antenna-array radio frequency (RF) receivers have been constructed by replicating RF receiver chains at each array element. Ignoring shared frequency references required for RF-input down-conversion, each receiver in such designs acts independently of its neighbors until the received signals reach the array beamformer. While the use of independent receiver chains is convenient, it is not the optimum and does not take advantage of the additional opportunities afforded by the light-cone concept. This work presents the first experimental demonstration of noise and distortion (ND) shaping. The NDs originating in the receiver itself are spatio-temporally shaped away from the beamformer region of support (ROS), thereby permitting their suppression by the beamformer. The demonstrator is a 24.3-28.7-GHz 79.28-mW 4-port receiver for a 4-element linear antenna array implemented in 22-nm FDSOI CMOS. When shaping was enabled, the demonstrator provided average improvements to the noise figure (NF) of 1.6 dB, IP1dB of 2.25 dB, and IIP3 of 1.4 dB (compared to a reference design), and achieved NF = 2.6 dB, IP1dB = −18.7 dBm, and IIP3 = −12.5 dBm while consuming 19.8 mW/ch.