  A planar technology stripline-fed slot radiating element in transmission
configuration is proposed. Its main advantages are the broad impedance
bandwidth achieved and the property that it only radiates into half-space,
which are obtained, respectively, with the use of its complementary strip
element and using a cavity-backed slot. A lattice network circuit model is
proposed both to explain the behavior of the structure and to establish a
design methodology. Its capabilities are shown through simulation and
demonstrated in a proof of concept prototype. Measurement results show a
unidirectional broadside radiation pattern and a fractional bandwidth of 48%,
significantly superior to other slot-based radiating elements found in the
literature. The element has the ideal characteristics for building series-fed
reconfigurable arrays for wide-band applications.
