  Antenna behaviors such as mutual coupling, near-field propagation, and
polarization cannot be neglected in signal and channel models for wireless
communication. We present an electromagnetic-based array manifold that accounts
for several complicated behaviors and can model arbitrary antenna
configurations. We quantize antennas into a large number of Hertzian dipoles to
develop a model for the radiated array field. The resulting abstraction
provides a means to predict the electric field for general non-homogeneous
array geometries through a linear model that depends on the point source
location, the position of each Hertzian dipole, and a set of coefficients
obtained from electromagnetic simulation. We then leverage this model to
formulate a beamforming gain optimization that can be adapted to account for
polarization of the receive field as well as constraints on the radiated power
density. Numerical results demonstrate that the proposed method achieves
accuracy that is close to that of electromagnetic simulations. By leveraging
the developed array manifold for beamforming, systems can achieve higher
beamforming gains compared to beamforming with less accurate models.
