A two-element slot line array antenna comprises a substrate having a first
and a second main surface, a conductor disposed on the first main surface,
a slot line formed in the conductor, and a pair of slot line antenna
elements formed in the conductor. The slot line has one end side
electromagnetically coupled to the pair of antenna elements, and the other
end side serving as a feed end. The pair of antenna elements is arranged
in parallel with an electric field plane or a magnetic field plane formed
by the slot line. The pair of antenna elements and the slot line are
arranged in mirror symmetry with respect to a magnetic field plane or
electric field plane which starts at the feed end, so that the pair of
antenna elements is excited in phase.
