Microstrip antennas have been widely used in many modern communication
systems, because of its robustness, planar profile, and low
cost.Most of these antennas operate at their fundamental mode,
which gives a broadside beam [4]. Microstrip antenna operating at the
higher order mode has dual symmetric radiation beams, with
each beam directed at respectively [5]–[7]. It is well known that
the major drawback of a microstrip antenna is its narrow bandwidth
( 3%). One of the popular techniques for broadening the patch antenna
bandwidth is to incorporate a U-slot on its surface as proposed
in [8] and [9]. However, the U-slot technique was studied only at the
fundamental mode of the patch [10]. To the best of authors’
knowledge, there is no published report on the study of the U-slot patch
antenna excited at the higher order mode.