BANDWIDTH ENHANCEMENT OF CIRCULARLY POLARIZED MICROSTRIP PATCH ANTENNA USING MULTIPLE L-SHAPED PROBE FEEDS

Impedance-bandwidth enhancement of microstrip antennas using an L-shaped probe feed has previously been demonstrated. In this paper, axial-ratio bandwidth enhancement is achieved for circularly polarized (CP) microstrip patch antenna using dual and four L-shaped probe feeds. By controlling the excitation phase and angular orientation of the horizontal portion of each L-probe, circular polarization can be generated with wide axial-ratio bandwidth by exciting the circular patch. In the dual L-shaped probe case, the impedance and axial-ratio bandwidth are 42% and 27.23%, respectively. On the other hand, for the four L-shaped probes case, both of these figures increase to 45%.