Design of Planar Microstrip Ultrawideband Circularly Polarized Antenna Loaded by Annular-Ring Slot

A miniaturized planar microstrip circularly polarized ultrawideband (UWB) antenna loaded by annular-ring slot is proposed and implemented in the paper. With radiating patch of antenna, side connected asymmetric inverted L-shaped microstrip. At same time, a quarter circle cut off from patch. The above designed structure shows improvements on operating frequency band realization circular polarization radiation. tapered placed between feed line to achieve slow-changing impedance transformation. results simulation measurement demonstrate that 3 dB axial ratio (AR) fractional bandwidth achieves 21.25%. peak gain within fluctuates 3.74 4.59 dBi. good matching range. compact UWB it has potential application various wireless communication devices.