Multichannel broadband Fano theory for arbitrary lossless antennas with applications in DOA estimation
In this paper, we consider fundamental limitations for DOA estimation with arbitrary lossless antennas or antenna arrays inserted inside a sphere. Spherical vector modes and their associated equivalent circuits and Q factor approximations are employed as a general framework for the analysis. The classical broadband matching theory by Fano is extended to a general multiport S-parameter model of the
