  The least upper bounds of the powers extracted and scattered by
bi-anisotropic particles are investigated analytically. A rigorous derivation
for particles having invertible polarizability tensors is presented, and the
particles with singular polarizability tensors that have been reported in the
literature are treated explicitly. The analysis concludes that previous upper
bounds presented for isotropic particles can be extrapolated to bi-anisotropic
particles. In particular, it is shown that neither nonreciprocal nor
magnetoelectric coupling phenomena can further increase those upper bounds on
the extracted and scattered powers. The outcomes are illustrated further with
approximate circuit model examples of two dipole antennas connected via a
generic lossless network.
