Abstract: In this paper, a miniaturized open slot helix antenna for satellite navigation terminal is proposed. The main body of the antenna consists of four open slot helix arms with gradual widths, printed on a square structure surrounded by a copper-covered dielectric substrates while the feeding network printed on the inner surface of the medium for coupling feeding. The feeding network consists of a looped structure on the bottom and a folded structure with a widened and upward side, which is fed at the bottom of the antenna using a coaxial connector. The size of the antenna is 26 mm×26 mm×29 mm. The measured results show that the impedance bandwidth of | S11 |≤-10 dB reaches 7. 88% (1. 523 GHz ~ 1. 826 GHz), and the circular polarization bandwidth with an axial ratio ≤3 dB is 20. 26% (1. 490 GHz~ 1. 826 GHz) . The gain at the center frequency of Beidou B1 (1. 561 GHz) , GPS L1 (1. 575 GHz) and GLONASS L1 (1. 602 GHz) are 3. 33 dBi, 3. 18 dBi and 2. 79 dBi respectively. The antenna adopts an open-slot helix structure, realizes the circular polarization of the antenna through serial coupling and feeding of a simple feeding network, and achieves wide bandwidth and better gain in the case of small size.