**Abstract**

In this chapter, three-dimensional microstrip antennas operating in the dominant TM10 mode of the L1 band at 1.57542 GHz are presented, which either provide uniform phase response and stable phase center, or wide angular beam coverage. A Finite-Difference Time-domain scheme has been developed and used to elucidate the interplay between the proposed antennas and several ground plane configurations. Experimental results are presented and compared to simulations to illustrate the impact of several 3-D geometries on the phase response, phase center, half power beam width, gain, and polarization purity. We report for the first-time novel threedimensional microstrip antenna topologies for precise surveying applications by fostering a nearly uniform phase response when the 3D structure is bent by angles ranging from 15° to 30° **without significantly compromising the gain and polarization performance** of the equivalent flat patch antenna. The proposed antennas exhibit half-power-beamwidths up to 40 and 80% greater than the equivalent flat structure that can be realized if positioned downward and upward respectively, for bend angles above 45° accompanied with a variety of spatial coverage patterns to suit applications involving highly dynamic platforms.

**Keywords:** three-dimensional (3D) microstrip antennas, global positioning system, low-elevation pattern coverage, GPS tracking of sounding rockets and unmanned aerial vehicles, GPS aerospace applications
