Study of a Novel Adaptive Printed Antenna Element for GPS Applications

摘要

This report discusses the development of a novel adaptive printed antenna element for GPS applications. This antenna element consists of a microstrip patch antenna and several diode-loaded parasitic metallic strips on top of the dielectric substrate. It is shown through computer simulations that the beamwith of the antenna can be modified by turning the diodes on or off. This implies that the radiated pattern level can be modified along the horizon (+100) This concept is based on controlling the surface wave behavior by adding metallic strips. The metallic strips convert, if properly designed, surface waves into leaky waves which radiated away from the surface of the substrate. It is shown through computer simulations and measurements that microstrip antennas can be built with thick substrates without the usual surface wave problem. An optimization algorithm is developed (Genetic algorithm) to design the metallic strips. The proper choice of the dimensions of the strips is important because their behavior is frequency sensitive.