GPS Antennas(for precise positioning Nearly all antennas are patch antennas (conducting patch mounted in insulating ceramic) Rings are called oke-rings (used to suppress multi-path) 04/1603 12540Lec17 Simple Multipath A simple approach to treating multipath is with ray-optics. Approach should be valid for reflectors that greater than one wavelength from the antenna It is important to note that all real antennas have gain below the horizon(ie, zero elevation angle) and will therefore see reflections from the ground 04/1603 12540Lec1704/16/03 12.540 Lec 17 11 GPS Antennas (for precise positioning) called choke-rings (used to suppress multi-path) Nearly all antennas are patch antennas 04/16/03 12.540 Lec 17 12 ray-optics. • Rings are (conducting patch mounted in insulating ceramic). Simple Multipath • A simple approach to treating multipath is with Approach should be valid for reflectors that greater than one wavelength from the antenna. • It is important to note that all real antennas have gain below the horizon (ie., zero elevation angle) and will therefore see reflections from the ground. 6