Wideband Dual Polarized Base Station Antenna

The thesis presents a study of different microwave radiators for wireless applications in the frequency range of 2.2 - 2.5GHz. Microstrip patch antennas and dual polarized dipole antennas were evaluated numerically and experimentally verified. A single microstrip patch and a four-element microstrip array were simulated, fabricated and tested. Simulation was carried out by the finite integration time domain (FITD) method. Polarization diversity is realised using crossed dipoles printed elements. For the crossed dipole elements, two different feed arrangements were studied. Parameters such as return loss, isolation, radiation pattern, gain and bandwidth were measured and found to be in good agreement with simulation. Several techniques were used to obtain broadband performance. Balanced and unbalanced feeder systems, substrates effects and the use of planar elements were investigated. Significant improvements were achieved in bandwidth and port-to-port isolation by optimizing the feed system and antenna geometry.