We study the performance of the minimum-noise-variance beamformer employing
a single electromagnetic (EM) vector sensor that is capable of measuring t
he complete electric and magnetic fields induced by EM signals at one point
. Two types of signals are considered: One carries a single message, and th
e other carries two independent messages simultaneously, The state of polar
ization of the interference under consideration ranges from completely pola
rized to unpolarized, We first obtain explicit expressions for the signal t
o interference-plus-noise ratio (SINR) in terms of the parameters of the si
gnal, interference, and noise. Then, we discuss some physical implications
associated with the SINR expressions. These expressions provide a basis for
effective interference suppression as well as generation of dual-message s
ignals of which the two message signals have minimum interference effect on
one another, We also analyze the characteristics of the main-lobe and side
-lobe of the ebeampattern of an EM vector sensor and compare them with othe
r types of sensor arrays.