Date of Award
Master of Science in Engineering (MSE)
Electrical and Computer Engineering
Z. A. Pour
Antennas (Electronics)--Design and construction.
A novel geometrical change is introduced to a broadband bowtie antenna to allow radiation beam tilting without the use of an engineered material. This is done by halving a standard triangular/elliptical bowtie antenna along the horizontal axis of symmetry. This causes an asymmetric current distribution to form, tilting the antenna’s equi-phase line. The location of this equi-phase line determines the amount of tilt provided by the antenna structure, and the line is controlled using the geometrical parameters that form the antenna. This technique may be applied to various antenna structures to achieve a tilted beam. Further bandwidth improvements are realized when the traditional triangular antenna is replaced with an elliptical equivalent. The elliptical geometry has greater surface area with smooth corners which allows the antenna to create a consistently well-defined radiation pattern. Using either geometry, the amount of tilt in free space across any given bandwidth could vary from 20° to 60° with a peak gain of 2.4 dBi. For the printed case, an elliptical half bowtie antenna is able to achieve a unidirectional radiation pattern tilted to approximately 40° along the useable bandwidth, which is a significant improvement over the engineered material. It has a peak gain of about 5 dBi and a front-to-back ratio greater than 10 dB.
Ake, William D., "A novel technique to tilt radiation beams in bowtie antennas" (2018). Theses. 247.