English (United Kingdom)

https://curated-unify.zendy.io/wp-json/zendy-region/v1/featured_content/oa?rat=en

https://curated-unify.zendy.io/wp-json/zendy-region/v1/highlighted_journal/

Global: Zendy Plus annual

Presents the access of premium content as premium feature

Premium Content

Presents the keyphrase highlighting as premium feature

Keyphrase Highlighting

Presents the summarisation as premium feature

Summarisation

Insights

Presents the pdf analysis as premium feature

PDF Analysis

Presents the zaia usage as premium feature

ZAIA

Global: Zendy Tools annual

Global: Zendy Free Plan

Global: Zendy Tools monthly

Global: Zendy Plus monthly

Nonuniform helical antennas have many degrees of freedom, which makes the search space for the optimal design very challenging. The objective of this paper is to systematically analyze nonuniform helical antennas with linearly varying geometrical parameters and to provide analytical equations that approximate the optimal design and the gain of the designed antennas. Using various optimization algorithms, we made a large database of the optimal nonuniform helical antennas with linearly varying geometrical parameters. Based on these results, we made analytical equations that approximate the optimal design and the gain of the designed antennas. These equations allow for a fast design procedure yielding all necessary parameters needed for the design and fabrication of nonuniform helical antennas that meet specified characteristics. Special attention is devoted to antenna losses. Antennas designed following the presented procedure achieve around 2.5 dB higher gain than uniform helical antennas of the same axial length, while maintaining the bandwidth and axial ratio. As a verification of the proposed design procedure, a helical antenna with the central operating frequency of 1 GHz was designed, simulated, fabricated, and measured. The comparison between measured and simulated results confirms the validity of the presented design procedure.

Design and Optimization of Nonuniform Helical Antennas With Linearly Varying Geometrical Parameters