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 Plus monthly

Global: Zendy Tools annual

Global: Zendy Tools monthly

Global: Zendy Free Plan

Very low-frequency (VLF) and ultralow-frequency (ULF) electromagnetic waves have the advantage of high penetration and low propagation loss in wireless communication systems and are mainly used for underwater and underground communications, as well as for earthquake and lightning forecasting. At present, VLF and ULF antennas are mostly bulky and require hundreds of antennas and more to be set up, which is costly and inefficient. In this paper, we propose to generate VLF and ULF signals by rotating a multilayer multipair electret thin-film electret driven by an excitation device, which improves the problem of low radiation efficiency of VLF and ULF signals and the large size of conventional low-frequency transmitting antennas. Based on a multilayer, multipair electret film mechanical antenna, a magnetic field propagation model is developed, and the relationship between the magnetic flux density mode and the number of layers of electret films, as well as the relationship between the antenna emission frequency and the motor rotation frequency and the number of pairs of electret films, is analyzed. The selection of a suitable model for practical situations based on conditions such as antenna size and propagation distance is illustrated. The research work is of great importance for guiding the design of mechanical antennas and optimizing antenna structures.

Study and Analysis of a Multilayer Multipair Electret-Based Thin-Film Mechanical Antenna