SIMPLE MECHANICALLY RECONFIGURABLE PATCH ANTENNAS

Reconfigurable antennas form an active subdivision of antenna and communications research primarily targeted at achieving reconfigurability in the RF, microwave, and millimeterwave frequency regimes. Mechanical, all-electronic, material based, and optical methods are the most common approaches to achieve reconfigurability. Each method can overlap to create new and innovative approaches to enable device tunability. The sub-class of reconfigurable antennas are antennas that dynamically achieve an adaptable transformation of their frequency, radiationpattern, polarization, and/or bandwidth characteristics to enable multiple dynamic functionalities. In this thesis, we designed new rectangular and triangular microstrip patch array antennas operating in the 5G midband at 5GHz. These patch antennas were designed and inspired by the Yagi-Uda antenna, where the driven and passive director or parasitic patches are the main elements. It was found that by increasing the number of parasitic elements, the antenna's gain can be improved, despite some impedance mismatch. The triangular patch array with the best result was then selected to further investigate its reconfigurability capability using two simple mechanically reconfigurable approaches, i.e., 1) single-plane and 2) double-plane patch arrays, focusing on the radiation pattern, gain, and operating frequency, and other antenna performances. The single-side and double-side folded structures were examined in both approaches, while the folded feeding line and curvature folded substrate were also studied in the single-plane patch array. The results provided clear evidence that by folding the substrate at varying angles one can effectively manipulate the antenna's radiation pattern, gain, and center operating frequency location. The impact varies with the degree of folding, signifying a direct relationship between the folding angle and the returning loss or S11 value. Three proposed microstrip array antennas, i.e., the single-plane patch antenna array, the triangle microstrip array, and the microstrip Yagi-Uda antenna array, were fabricated and tested. The simulation and measurement results are in good agreement.