Circularly polarized single-fed wide-band microstrip elements and arrays

For more than 25 years the circularly polarized single-fed microstrip patch are considered to be extremely narrow-band. The performances reported are almost exclusively related to single-patches printed on a dielectric substrate, which partially explains the frequency characteristics. The antenna proposed is a variation of the 'almost square' patch and exhibits an axial radio of less than 2.5 dB over a more than 10% bandwidth. The antenna was designed for PCN and PCS applications.