Abstract: A helix antenna including a first radiating element extending helically about a longitudinal axis and tuned to resonate in a frequency band, a reactive element electrically connected to a first end of the first radiating element, and a second radiating element extending helically about the axis and electrically connected to the reactive element at a first end of the second radiating element, wherein the second radiating element is tuned to resonate in the frequency band.

Abstract: A helix antenna including a first radiating element extending helically about a longitudinal axis and tuned to resonate in a frequency band, a reactive element electrically connected to a first end of the first radiating element, and a second radiating element extending helically about the axis and electrically connected to the reactive element at a first end of the second radiating element, wherein the second radiating element is tuned to resonate in the frequency band.

Abstract: An electrically small supergain endfire transmitting and receiving array antenna comprising at least one first resonant element with a first input terminal. The first resonant element driven by a power supply voltage supplied at the first input terminal. The electrically small supergain endfire transmitting and receiving array antenna further includes at least one second resonant parasitic element with a second input terminal. The second input terminal shorted and the second resonant element spaced less than about 0.25? from the first resonant element at any corresponding point. The antenna has a gain of at least 6 db and ka<1.0.

Abstract: The Genetically Optimized Digital Ionospheric Sounding System (DISS) Transmit Antenna is a low-cost modification to the TCI 613F HF communications antenna that increases and stabilizes vertical gain from 4 to 30 MHz. Genetic algorithm and local search techniques were used in the design of the modification in order to take into account both electrical design and mechanical simplicity in this design. The novelty lies in the specific placement of conducting wires with respect to the original TCI antenna. This placement both increases the vertical gain of the antenna as a whole and adds to its stability as each wire also acts as a guy cable.