Design of Broadband Antenna Elements and Phased Arrays for Applications in the GPS Frequency Region

The global positioning system (GPS) plays nowadays an outstanding role in positioning finding and navigation for both military and civil applications. However, typical commercial GPS antennas mostly show only a small bandwidth of about 20 MHz making them rather sensitive with regard to variations of geometrical and material parameters. Therefore we have developed stacked microstrip antennas for the L1-frequency as well as for the L2-frequency using an iterative design process for bandwidth maximization. With this design process we reach a bandwidth of up to 25 % for the return loss and 18 % for the axial ratio (6 dB) allowing the use of standard laminates for the dielectric layers. Furthermore we have developed a 7-element phased array which can e.g. be used for the localization of GPS-jammers as well as for an active distortion suppression. For the design process both commercial software packages and an internal software framework based on integral equation approaches were used.