Note to moderator: Read answerline carefully. In 2017, Emil Björnson proposed a technology that deploys large-scale instances of these systems to improve spectral efficiency. These systems may use diversity schemes to mitigate the effects of fading. These systems may use zero-forcing or maximum ratio-combining to facilitate massive MIMO through beamforming. (-5[1])A Butler matrix feeds into the phased type of these systems, which can suffer from beam squint. (10[1])One driven element and multiple parasitic elements make up the Yagi–Uda (10[2])type (10[1])of these (10[1])systems. Data collected from these systems acting as interferometers is mixed using aperture (-5[1])synthesis during VLBI. (-5[2])Karl (-5[1])Jansky (10[1])lends his name to a so-called “very large” (10[2]-5[1])one of (-5[1])these systems. (10[2]-5[1])For 10 points, name these systems composed (10[1])of specialized transducers, used to transmit and receive electromagnetic waves. (10[1])■END■ (10[7])