**Sulaiman Tariq**

**1**

**Chapter 1**

**Abstract**

Three-Dimensional Microstrip

*Ken G. Clark, Jim M. Tranquilla and Hussain M. Al-Rizzo*

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

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

The design requirements of a global positioning system (GPS) antenna rely on the application under consideration. A GPS user antenna is required to exhibit right-hand circular polarization (RHCP) and RHCP radiation pattern coverage from zenith down to five elevations for all azimuth angles to maintain tracking of the full visible satellite constellation during dynamic maneuvers [1–7]. An equally important, yet more challenging requirement is that the antenna must provide a virtually uniform phase response and stable phase center over the coverage region to satisfy precise position-

In this chapter, three-dimensional microstrip antennas operating in the dominant

Antennas for Uniform Phase

Response or Wide-Angular

Coverage GPS Applications

applications involving highly dynamic platforms.

vehicles, GPS aerospace applications

ing accuracy requirements [8–10].

**1. Introduction**

Wireless Systems Engineer (Apple Inc.), Cupertino, USA
