NOVEL IMPLEMENTATIONS OF PLANAR ANTENNAS WITH GOVERNABLE CIRCULAR POLARIZATION
1 online resource (89 pages) : PDF
University of North Carolina at Charlotte
This document is an explicit and an exclusive account on two antennas. This literatureis an attempt to solve some of the challenges for planar antennas in the frequencyindependent class and exploit the radiative nature of narrow band patch antennaarrays to new capabilities.The first antenna is a rectangular patch element array with two ports and operatesat 5GHz. The structure is designed to emit circularly polarized waves. The righthandednessor left-handedness of this emitted wave can be changed dynamically byswitching the ports. This attribute is coined as "Encrypted Polarization" in thisdocument. The presence of two ports in the design is further exploited to theoreticallyintroduce the idea of using this antenna as a filter element. The measured results showa 6% shift in the operating frequency when compared with the simulated results. It isthen proved that a discrepancy in the value of the dielectric constant of the substrateis responsible for this variance.The second antenna is a modification of a conventional Archimedean Spiral Antenna(ASA). The arms of the spiral are kept on either side of the substrate and the arms ofthe spiral are wider than a tradiational design. The feed of the antenna is remarkablysimplified by introducing the opportunity of attaching the coaxial connector directlyat the center of the spiral. A 50 input impedance is obtained for the structurebecause of change in the metal to slot ratio. A simulated bandwidth of 40 : 1 isobtained with the antenna operating from 700MHz to 29:9GHz. The actual resultschange the upper limit to 19GHz. Fabrication limitations in the physical design isassumed to be the root cause for this inconsistency.
Weldon, ThomasHan, Tao
Thesis (M.S.)--University of North Carolina at Charlotte, 2018.
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