Compact CPW-Fed Planar Monopole Antenna With Wide Circular Polarization Bandwidth

The design and implementation of a coplanar waveguide-fed planar monopole antenna with circular polarization and broadband operation is presented. The antenna operates in the Industrial, Scientific, and Medical (ISM) and wireless local area network (WLAN) (5 GHz) bands with circular polarization (CP) in both bands. It is demonstrated that a fractional bandwidth for CP larger than 33% can be attained simply by introducing an inverted L-shaped slot in the ground plane and parallel-aligning an inverted-L-shaped strip. The advantages of the proposed antenna are the simple yet efficient design of the radiator, a wide 3-dB axial-ratio operating band, and a compact size.