The extraordinary radiation pattern of an optical rod antenna

TL;DR

This paper explores the unique radiation pattern of optical rod antennas, revealing how a specific parameter influences directivity and offers new design possibilities for optical antenna performance enhancement.

Contribution

It introduces the parameter Lambda and demonstrates its significant impact on radiation patterns and directivity in optical rod antennas, differing from conventional radio-wave antennas.

Findings

Lambda greatly influences the radiation pattern.

Higher resonant order patterns can be side-lobe free.

Optical antennas can achieve sharper directivity.

Abstract

We investigated the radiation pattern of an optical rod antenna and found that it had many features compared with its conventional radio-wave equivalents. After defining a parameter {\Lambda} = {\lambda}eff /{\lambda}, which was the ratio of the effective wavelength of the rod antenna to the incident wavelength, we found that {\Lambda} had a great influence on the radiation pattern. Even the radiation pattern with a higher resonant order is without side lobes and results in a sharper directivity, which provides new design flexibilities in improving the directivities of the optical antennas.