DESIGN ISSUE :ELECTRICALLY SMALL ANTENNA •An antenna smaller than 0.1 wavelength –Cutler is approx. 300m/20,000m = .015 •Antenna bandwidth is limited •Radiation resistance is very small and in series with ground loss and tuning network loss •Increasing height and adding capacitive top load increases radiation resistance

2020年5月3日 · Abstract : in this Post we describe the construction and tuning of a magnetic loop antenna whose purpose is reception in the VLF band, to be coupled with a suitable VLF receiver for monitoring SID events (sudden ionospheric disturbances) caused by solar flares.

This document details the construciion mcthixi for building the VLF/LF receive loop antenna as designed by Mr. Don Watt of Watt Engineering. The second portion of this report describes the Heimholte loop calibration procedure.

2024年11月28日 · Optimizing the antenna Geometry can yield higher radiation intensity and extend transmission distance. This flexible and low-cost design method expands the application potential of loop antennas in VLF communication and …

Emergent magnetoelectric (ME) antennas driven by piezoelectric materials have become a promising solution for miniaturizing very low frequency (VLF) communication systems. Here, a theoretical model between the radiation performance and piezoelectric material properties of the ME antenna was conducted.

VLF antennas operate on VLF band. They are electrically small and this simplifies analysis. They are physically large structures. In other words, they generally have a number of towers that 200-300 m high and cover areas of up to a square kilometer or more. The VLF antennas support worldwide communication .

The same antenna fundamentals apply at any frequency, but with a few important differences. At the higher frequencies, a quarter wavelength or a half-wavelength becomes a practical dimension, and at HF, VHF and UHF monopole antennas can be elevated, remote from the ground beneath.

The beginning of the modern era of computer aided design is traced here in the design of the US Navy's high power VLF transmitting antenna at Lualualei, Hawaii. The roles played by the use of physical scale models and by computer simulation are …

The article discusses the theory of loop aerials for receiving and how they reduce the level of local noise. A Loop Aerial is described suitable for use on the LF and VLF bands together with a circuit of an interface loop tuner and preamplifier. The discussion extends to the problems of amplifier noise and the advantages of tuning the loop.

Time/frequency reassigned VLF spectrogram with RSDN (horizontal lines) and sferics (vertical lines). Received with the air-core loop antenna indoors, and an SDR-IQ (software-defined radio).