Circularly Polarized S-Band Satellite Antenna With Parasitic Elements and Its Arrays

Abstract

A structural modification of S-band turnstile antenna with cylindrical parasitic elements around a main radiator is introduced and investigated with respect to its gain, axial-ratio (AR) beamwidth, and radiation pattern. The overall structure is composed of a main radiator of two crossed bowtie-shaped dipole antennas and a feeding network using a Wilkinson power divider with phase differences between two parts. A final optimization of the parameter values for the enhancement of AR beamwidth is carried out from the parametric studies. The proposed antenna has not only a broad 5-dB AR bandwidth of 12.3% ranging from 2025 to 2290 MHz, but also a stable peak gain of 7.6 dBic with circular polarization (CP) characteristic.