Date of Award


Document Type


Degree Name

Doctor of Philosophy (PhD)


Electrical and Computer Engineering

Committee Chair

Maria Pour

Committee Member

Tony Gatlin

Committee Member

David Pan

Committee Member

Richard Lieu

Committee Member

S. Ravindran


Phased array antennas, Electronically Displaced Phase Center Antenna (E-DPCA)


Phased array antennas are widely used in a variety of military and civilian applications. For a given application, their radiation characteristics, such as the sidelobes, position of the nulls, and the main beam direction, need to be altered to enhance the array performance. To control these properties for a given requirement, the elements of phased array antennas need to be either properly excited or physically rearranged in different periodic and aperiodic configurations. However, once the position of the elements is fixed to control a single aspect of the generated pattern, it cannot simultaneously fulfill any other specification. To further alter the array radiation patterns and increase its efficiency, the antenna elements need to be rearranged mechanically. This makes the entire process rigorous, time consuming and expensive. Hence, a new method of developing phased array antennas with reconfigurable element spacing to electronically generate adaptive radiation patterns without using any mechanical means is proposed in this dissertation. In antenna engineering, the exact coordinates of the antenna element in space are determined by its phase center location, which is the effective source of radiation. The dual-mode circular microstrip patch antenna can electronically displace the phase center location by properly exciting its first two transverse magnetic modes. In the proposed research, the dual-mode patch antennas are employed as the base elements in N-element linear and planar arrays to electronically rearrange the element position to adaptively alter the radiation patterns and generate patterns with desired characteristics such as reduced sidelobe levels and steerable nulls without any physical displacement. The proposed concept is validated by the full-wave analysis, fabrication and measurement of the phased array antenna designs, successfully confirming the practical implementation of the proposed technique in adaptive phased array antennas to develop desired radiation patterns without any mechanical rearrangement. Thus, the proposed concept has the potential to transform the next generation of phased array antennas in radar applications, as this technology leans towards a greater degree of automation and autonomy.

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