DESIGN AND IMPLEMENTATION OF RECONFIGURABLE PATCH ANTENNAS FOR WIRELESS COMMUNICATIONS

Reconfigurable patch antennas have drawn a lot of research interest for future wireless communication systems due to their ability to adapt to changes of environmental conditions or system requirements. The features of reconfigurable patch antennas, such as enhanced bandwidths, operating frequencies, polarizations, radiation patterns, etc., enables accommodation of multiple wireless services. The major objective of this study was to design, fabricate and test two kinds of novel reconfigurable antennas: a dual-frequency antenna array with multiple pattern reconfigurabilities, and a pattern and frequency reconfigurable Yagi-Uda patch antenna. Comprehensive parametric studies were carried out to determine how to design these proposed patch antennas based on their materials dimensions and their geometry. Simulations have been conducted using Advanced Design Systems (ADS) software. As a result of this study, two kinds of novel reconfigurable patch antennas have been designed and validated at the expected frequency bands. For the new reconfigurable antenna array, the beam pattern selectivity can be obtained by utilizing a switchable feeding network and the structure of the truncated corners. Opposite corners have been slotted on each patch, and a diode on each slot is used for switchable patterns. By controlling the states of the four PIN diodes through the corresponding DC voltage source, the radiation pattern can be reconfigured. The simulation and measurement results agree well with each other. For the novel frequency and pattern reconfigurable Yagi-Uda patch antenna detailed in Chapter 4, two slots have been used on driven element to achieve frequency and pattern reconfigurability, and two open-end stubs have been used to adjust working frequency and increase bandwidth. In this design, an ideal model was used to imitate a PIN diode. The absence and presence of a small metal piece has been used to imitate the off-state and on-state of the PIN-diode. Pattern reconfigurability and directivities with an overall 8.1dBi has been achieved on both operating frequencies. The simulation and measurement results agree closely with each other. Advisor: Yaoqing Yan