In this study, the design, fabrication, and performance of a small high-gain global positioning system (GPS) antenna that generates dual orthogonal circular polarization using a novel six-terminal feeding network is presented. The proposed six-terminal feeding network has two input quadrature terminals and four output terminals having the same amplitude and 0° or 180° phase. Therefore, it is suitable for feeding the four radiating elements with linear polarization characteristics. To realize a

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... ual orthogonal circular polarization antenna with miniaturization and high gain characteristics, the six-terminal power supply network is positioned in the center of the antenna, and the four radiating elements are arranged on the outside. The radiating element selected after considering the limited space is a three-dimensional printed dipole element with linear polarization characteristics which is rotated by 90°. The antenna size designed optimally in the GPS L1 band (1,575.42±12 MHz) is less than 130 mm (0.68 λ 0 ) in diameter (D) and 40 mm (0.21 λ 0 ) in height. The antenna's input return loss and port isolation characteristics measured with a vector network analyzer are excellent within the band at 17.1 dB and 18.0 dB or more, respectively. In addition, the antenna gain, and efficiency measured in the anechoic chamber are 8.69 dBi (@bore-sight) or more and 83 % or more, respectively. Furthermore, it can be seen that the axial ratio characteristics of the dual orthogonal circular polarization wave are very good, with less than 0.2 dB (@bore-sight) and less than 1.8 dB (@ 3 dB beam width).