Design of a Compact GPS Antenna Using Thermoplastics.

The Global Positioning System (GPS) is a satellite-based radio navigation system, which provides geo location, navigation and real time tracking information. It is used during Non-Line of Sight (NLOS) situations, when the weak GPS signals get obstructed by mountains, etc. However, the functionality of GPS tracking devices has evolved since its early inception owing to its countless benefits. Instead of mainly focusing on tracking, they are used for various applications such as inhibiting car theft and support for road accidents. This development in the field of satellite communication has increased the demand for satellite services from all sectors especially the automotive industry. The GPS antenna is the backbone of the GPS system. Therefore, we require a commercially viable design that meets the size (0.105λo x 0.105λo x 0.02λo) requirement of the automobiles. In this paper, we discuss the substrate material solutions to design an affordable yet flexible GPS antenna. The incumbent ceramic (↋r = 38) is replaced by a thermoplastic (↋r =11) to aid design flexibility. However, shifting to lower dielectric material raises miniaturization challenges as the dielectric constant is proportional to size of the antenna. This helps to reduce manufacturing and processing cost as the antenna is lightweight and compact, thereby providing a space efficient solution for the automotive industry. This paper presents the design for a GPS antenna with a square ring slot in the periphery of its radiating patch and truncated edges on the substrate to achieve the frequency of 1.575 GHz with right hand circular polarization.