A Novel Technique of Broadband Circularly Polarized Microstrip Antenna Development withSquare Ring Slot for SAR Application

This paper presents a novel technique to develop a broadband circularly polarized microstrip antenna by using square ring slot (SRS) for SAR application. The minimum requirements of proposed antenna are 800MHz bandwidth with the resonant frequency at 9.4GHz and workable in circular polarization. To satisfy a broadband bandwidth characteristic, a novel technique, called as SRS technique, is implemented upon the patch radiator. The proposed antenna is designed to produce the left-handed circular polarization (LHCP). It is etched on double layer of NPC-H22A dielectric substrate with the dielectric constant of 2.17 and the thickness of 1.6mm. By implementing SRS technique on the proposed antenna, the bandwidth of axial ratio achieved of 12.7% (8.7GHz–9.9GHz), the impedance bandwidth of 36% (8.5GHz–11.9GHz), and the gain achievement up to 6dBic.