Design, simulation, construction, and characterization of a wideband 900MHz-2.25GHz helical antenna

High power wideband helical antennas are currently being designed, simulated, and constructed at the University of Missouri-Columbia´s Center for Physical and Power Electronics laboratory. The program CST Microwave Studio was used to simulate antenna designs derived from Krauss´s formulas. Once simulations proved to be functional, the antennas were constructed, characterized, and compared against their simulated results. In order to maximize performance a tapered stripline transformer of appropriate dimensions was added to match the input impedance to that of the antenna, resulting in a lower VSWR and a much larger operational bandwidth. The stripline matched a 50 ohm source impedance to the 125 ohm load and was 1.3λ long. This paper describes the necessary steps, design parameters, and building techniques necessary to construct an ideal wideband helical antenna.