Theoretical proposal for the experimental realisation of a monochromatic electromagnetic knot

TL;DR

This paper presents a theoretical design for a spherical antenna capable of generating monochromatic electromagnetic knots in the microwave domain, enabling new experimental studies of complex electromagnetic field structures.

Contribution

It introduces a novel antenna configuration that can produce electromagnetic knots, bridging theoretical concepts with practical experimental realization.

Findings

Numerical simulations show the antenna can generate linked and knotted electromagnetic fields.

A specific antenna design with 20 element pairs at 2.45 GHz approximates electromagnetic knots.

The proposed antenna can be used to excite plasmas locally.

Abstract

We propose an antenna designed to generate monochromatic electromagnetic knots and other "unusual electromagnetic disturbances" in the microwave domain. Our antenna is a spherical array of radiating dipolar elements configured to approximate the desired electromagnetic field near its centre. We show numerically that a specific embodiment of the antenna with a radius of 61.2 cm and only 20 element pairs driven at a frequency of 2.45 GHz can yield linked and torus-knotted electric and magnetic field lines approximating those of an "electromagnetic tangle": a monochromatic electromagnetic knot closely related to the well-known Ra\~nada-Hopf type electromagnetic knots but simpler in its construction. The antenna could be used to locally excite plasmas.