Circularly Polarized Bandwidth-Enhanced Crossed Dipole Antenna With a Simple Single Parasitic Element
A method of using a simple single parasitic element to significantly enhance a 3-dB axial-ratio (AR) bandwidth of a crossed dipole antenna is presented. This approach is verified by introducing one bowtie-shaped parasitic element between two arms of crossed bowtie dipoles to generate additional resonance and thereby significantly broadening AR bandwidth. The final design, with an overall size of 0.79 <italic>λ<sub>o</sub></italic> × 0.79 <italic> λ<sub>o</sub></italic> × 0.27 <italic>λ<sub>o</sub></italic> (<italic>λ<sub>o</sub></italic> is the free-space wavelength of circular polarized center frequency), resulted in very large measured –10-dB impedance and 3-dB AR bandwidths ranging from 1.9 to 3.9 GHz (∼68.9%) and from 2.05 to 3.75 GHz (∼58.6%), respectively. In addition, the antenna also yielded a right-hand circular polarization with stable far-field radiation patterns and an average broadside gain of approximately 8.2 dBic.