This still requires an antenna tuned to the appropriate wavelength, and for matching you cannot have all antennas connected at the same time, they must be switc

This still requires an antenna tuned to the appropriate wavelength, and for matching you cannot have all antennas connected at the same time, they must be switched, so this would be unable to receive all frequencies at the same time. The paper also indicates this is a heterodyne technique, so you have to tune to a center frequency like a radio, and the receptivity looks very narrow.