# Highly Directive Biconic Antennas Embedded in a Dielectric

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*Applied Sciences*: Invited Papers in Electrical, Electronics and Communications Engineering Section)

## Abstract

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## Featured Application

**efficient and secure point-to-point wireless communication; radiating energy transfer systems**

## Abstract

## 1. Introduction

## 2. Motivation

## 3. Contributions

## 4. An Extended Formulation for Electrodynamics

## 5. Free-Waves

## 6. Numerical Methods

## 7. Design of the Directional Antenna

## 8. Numerical Simulations

## 9. Highly Directional Emissions

## 10. Conclusions

## Author Contributions

## Funding

## Conflicts of Interest

## References

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**Figure 1.**Different wave case studies occurring in a cylindrical environment. For $\alpha =\pi /2$ and $z>0$ (

**left**), we can get solitons with propagation fronts shifting unperturbed in the direction of the vertical axis. For $\alpha =0$ (

**right**), the fields belong to a torus that expands radially as time passes. The intensity of the signal decreases with the distance r. For $\alpha =\pi /4$ (

**middle**), we have an intermediate situation where the ring increases in magnitude escaping from the origin. In all cases the magnetic field $\mathit{B}$ has zero divergence and turns around the z-axis, as specified in figure.

**Figure 2.**A biconic antenna (upper and lower blue cones) is surrounded by a dielectric of a suitable shape (pink ellipsoid-like body). The aim is to get an output signal where the Poynting vectors are aligned horizontally. The black arrows are initially omnidirectional, but they emerge from the dielectric with zero components along the z-axis.

**Figure 3.**Inverse problem to be solved for the determination of the surface $\partial \Omega $. After refraction, a ray coming from the origin with a certain angle $\alpha $ must emerge perfectly horizontal.

**Figure 4.**Shapes of $\partial \Omega $ for different values of the relative permittivity coefficient: from left to right, ${\u03f5}_{r}=2,3,4,5,6,7$.

**Figure 5.**Displacement of the vector field $\mathit{V}$ within the computational domain for $N=40$. The antenna boundaries are represented by the solid lines. The plot on the left-hand side shows $\mathit{V}$ when the dielectric is absent. In this case we have $\left|\mathit{V}\right|=1$. On the right-hand side, $\mathit{V}$ is radial with $\left|\mathit{V}\right|=1/\sqrt{{\epsilon}_{r}}$ inside the dielectric, and horizontal with $\left|\mathit{V}\right|=1$ outside. The situation is referred to the choice ${\epsilon}_{r}\approx 2$ (see the left-most curve in Figure 4), so that $1/\sqrt{{\epsilon}_{r}}\approx 0.7$.

**Figure 6.**(

**Left**) displacement of the initial vector field $\mathit{E}$ for $N=40$ and $\omega =7$. (

**Right**) how Neumann type boundary conditions are imposed on the perfectly conducting antenna guide.

**Figure 7.**Evolution of $\left|\mathit{E}\right|$ when the dielectric is not present. Simulation parameters: $L=1$, $N=120$, $T=1.2$ and $\Delta t=1/1800$. The propagation velocity is $c=1$.

**Figure 8.**Evolution of $\left|\mathit{E}\right|$ in presence of the dielectric. Simulation parameters: $L=1$, $N=120$, $T=1.4$ and $\Delta t=1/1800$. The propagation velocity is $c=0.7$ in the dielectric and $c=1$ outside.

**Figure 9.**Evolution of $\left|\mathit{E}\right|$ by following the classical Maxwell model. Simulation parameters: $L=1$, $N=120$, $T=1.2$ and $\Delta t=1/1800$. The propagation velocity is $c=1$.

**Figure 10.**Antenna completed with a conical reflector. The final output signal has parallel Poynting’s vectors. The magnetic field envelopes closed circles around the z-axis. The solitonic wave is expected to travel by carrying its associated information without dissipation.

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**MDPI and ACS Style**

Chiolerio, A.; Diazzi, L.; Funaro, D.
Highly Directive Biconic Antennas Embedded in a Dielectric. *Appl. Sci.* **2020**, *10*, 8828.
https://doi.org/10.3390/app10248828

**AMA Style**

Chiolerio A, Diazzi L, Funaro D.
Highly Directive Biconic Antennas Embedded in a Dielectric. *Applied Sciences*. 2020; 10(24):8828.
https://doi.org/10.3390/app10248828

**Chicago/Turabian Style**

Chiolerio, Alessandro, Lorenzo Diazzi, and Daniele Funaro.
2020. "Highly Directive Biconic Antennas Embedded in a Dielectric" *Applied Sciences* 10, no. 24: 8828.
https://doi.org/10.3390/app10248828