Progress In Electromagnetics Research Letters · 2013 · 16 citations · 8 references
EngineeringElectrical EngineeringAntennasGeometryGlobal Navigation Satellite SystemsAntenna DesignAntenna GainAntenna Impedance MatchingMicrostrip AntennasMicrowave AntennasPlanar AntennasAnnular Ring Microstrip AntennasAxial RatioBandwidthCircularly Polarized Antenna DesignCircularly Polarized Antenna GainCircularly Polarized AntennasCircularly Polarized Microstrip AntennasMicrostrip Antenna Design
A novel design of circularly polarized (CP) annular-ring microstrip antenna (ARMSA) working in TM11 mode is presented. The CP radiations of the proposed antenna are implemented by a 90 - branch-line hybrid coupler placed at the inner part of the ARMSA. Since the ARMSA has narrow bandwidth and high-input impedance, a circular parasitic patch suspended above the ring is employed for not only improving the impedance matching and bandwidth, but enhancing the performances of axial ratio (AR). Due to the utilizing of parasitic patch and circular hybrid, the measured results are shown to attain a 10-dB return loss bandwidth of 31.2% (1300{1780MHz) and a 3-dB AR bandwidth of 19.2% (1360{1650MHz) respectively. The CP gain is 8.2dB at 1.575GHz. The proposed antenna is low proflle and has a simple structure, therefore, it can be a good candidate for GPS portable terminal applications.
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