The design of broadband circularly polarized microstrip antenna

A broadband circularly polarized microstrip antenna is provided in this paper. Antenna has dual substrate, one air layer and single circular metal disk, as radiate patch. The dual capacitively coupled feed disk are contacted with the Wilkinson power divider, the power of the two outputs is equal in amplitude and 90-degree phase shift. The 3dB axial ratio bandwidth is as large as 56%, the VSWR < 2-impedance bandwidth of about 64%, the 1dB variations of antenna gain bandwidth of about 52%. The polarized feature of antenna pattern is well in 30% bandwidth.