I. Introduction
Global Navigation Satellite System (GNSS) was introduced in 1970, with full operational capabilities in 1995. This system was then combined with various other positioning systems to be known today as Global Navigation Satellite System (GNSS), which employs different frequency bands [1] . The L1 band is widely used signal for satellite navigation and is employed by most satellite navigation applications, devices and systems worldwide [2] . It is also referred as L1 CA (Coarse Acquisition). Circular polarization (CP) characteristic is one of the important requirements in GNSS antenna design. Apart from GNSS, CP antennas have also been designed for various other applications such as WiFi [3] , LTE [3] , 5G [4] and RFID [5] . Different types of materials have been also adopted for such antennas, including flexible [6] and non-flexible [7] types.