High Refractive Index Electromagnetic Devices in Printed Technology Based on Glide-Symmetric Periodic Structures

Abstract

We demonstrate the beneficial effects of introducing glide symmetry in a two-dimensional periodic structure. Specifically, we investigate dielectric parallel plate waveguides periodically loaded with Jerusalem cross slots in three configurations: conventional, mirror- and glide-symmetric. Out of these three configurations, it is demonstrated that the glide-symmetric structure is the least dispersive and has the most isotropic response. Furthermore, the glide-symmetric structure provides the highest effective refractive index, which enables the realization of a broader range of electromagnetic devices. To illustrate the potential of this glide-symmetric unit cell, a Maxwell fish-eye lens is designed to operate at 5 GHz. The lens is manufactured in printed circuit board technology. Simulations and measurements are in good agreement and a measured peak transmission coefficient of −0.5 dB is achieved.

On the Benefits of Glide Symmetries for Microwave Devices

“…For example, glide-symmetric metallic pins also present advantages with respect to conventional pins, as demonstrated in [61], [62], [88]. Similar benefits were demonstrated in planar technologies [89]- [91]. Fig.…”

Dispersion Analysis of Periodically Loaded Transmission Lines with Twist Symmetry Using the Mode-Matching Technique

“…Recent studies of glide-symmetric structures have demonstrated the absence of the stop-band between the first and second modes [11,12]. Additionally, it has been demonstrated that glide-symmetric structures are less dispersive [12,13] and can provide a higher effective refractive index [13][14][15][16], effective permeability [17], and level of anisotropy [18], compared to their non-glide counterparts. These properties have been used to design planar lenses in [13,[19][20][21][22].…”

“…Additionally, it has been demonstrated that glide-symmetric structures are less dispersive [12,13] and can provide a higher effective refractive index [13][14][15][16], effective permeability [17], and level of anisotropy [18], compared to their non-glide counterparts. These properties have been used to design planar lenses in [13,[19][20][21][22]. Furthermore, while the stop-band between the first two modes is suppressed in glide-symmetric structures, a large stop-band exists at higher frequency [23][24][25].…”

Two-Dimensional Glide-Symmetric Dielectric Structures for Planar Graded-Index Lens Antennas

“…Another relevant quality of glide symmetry is that it increases the equivalent refractive index of periodic structures and its bandwidth [17], [18]. These features were used to produce broadband 2D lenses [19]- [21] and artificial materials [22], [23]. For example, in [21], glide symmetry was proposed to produce a Maxwell fish-eye lens in printed technology.…”

“…These features were used to produce broadband 2D lenses [19]- [21] and artificial materials [22], [23]. For example, in [21], glide symmetry was proposed to produce a Maxwell fish-eye lens in printed technology.…”