Design of low volume circularly polarized annular ring-shaped planar antenna for GPS applications

摘要

A brand-new low volume design of an antenna working at three discrete bandsof Global Positioning System namely L1, L2, and L5 bands with preferred righthand circular polarization (RHCP) radiation has been presented in this article.The radiator of RHCP antenna is designed by using eight 45° rotated microstripsinside the narrow width annular patch and two rectangular groundplanes is incorporated on the same side of the dielectric material to exhibit acoplanar wave guide feed. The TM11 and TM22 modes were used to achieveRHCP radiation at global positioning system (GPS) L1 (1.5754 GHz), L2(1.2276 GHz), and L5 (1.1764 GHz) bands. This structure has low volume of107.5 × 96 × 1.6 mm~3, an excellent 3 dB beam-width of about 95°, 100° and102° in θ = 0° direction and an optimum axial ratio band-width of 56 MHz(1.554-1.610 GHz), 46 MHz (1.203-1.249 GHz), and 46 MHz (1.157-1.203 GHz).The measured results of S11 ascertained that the designed antenna is capableto efficiently work from 1.140 to 1.276 GHz (136 MHz) and from 1.545 to1.588 GHz (43 MHz), respectively, which well suited for GPS L1, GPS L2, andGPS L5 applications.