Dual-Frequency Ring Patch Antennas for GPS

Global positioning system (GPS) is widely used for car-navigation system all over the world. At present, GPS system employs only the frequency of 1.57542 GHz (L1) in the civilian use. Recently, to improve the positioning accuracy, GPS modernization enterprise is scheduled and executing. For the final stage new GPS satellites which is launched in 2014, additional two new frequency signal transmitters that are for the frequency of 1.22760 GHz (L2) and 1.17645 GHz (LS) is equipped. Prior to the final stage, the first stage new GPS satellites are launched in July, 2005. This satellite equips the transmitters for the frequencies of 1.57542 GHz (L1) and 1.22760 GHz (L2). In this paper, we propose compact, small, and low-profile dual-frequency operation microstrip antennas for this first stage new GPS system