Research Article

Propagation characteristics of periodic structures possessing twist and polar glide symmetries

¹ Department of Electromagnetic Engineering, KTH Royal Institute of Technology, 10044 Stockholm, Sweden
² Laboratoire d'Électronique et Électromagnétisme, Sorbonne Université, 75005 Paris, France

^* Corresponding author: oskdah@kth.se

Received: 21 November 2018
Accepted: 4 March 2019
Published online: 28 March 2019

Abstract

In this article, we provide an overview of the current state of the research in the area of twist symmetry. This symmetry is obtained by introducing multiple periods into the unit cell of a periodic structure through a rotation of consecutive periodic deformations around a symmetry axis. Attractive properties such as significantly reduced frequency dispersion and increased optical density, compared to purely periodic structures, are observed. The direct link between the symmetry order and these properties is illustrated through numerical simulations. Moreover, polar glide symmetry is introduced, and is shown to provide even further control of the dispersion properties of periodic structures, especially when combined with twist symmetry. Twist symmetries can, with benefit, be employed in the development of devices for future communication networks and space applications, where fully metallic structures with accurate control of the dispersion properties are desired.