Phase quantized quasi-Sierpinski carpet reflector for OAM beam generation

Rajanikanta Swain,Rabindra Kishore Mishra

doi:10.1063/1.5048070

Abstract

This work proposes a quasi-Sierpinski carpet type reflecting surface. The reflector incorporates remodeled Jerusalem type sub-wavelength elements. The element arrangement ensures a 3-bit phase quantized encoding for the reflected beam. Microstrip antenna feed illuminates this reflector. We start with EM simulation of a broadband unit-cell reflector. We assume that the final reflector based on such unit-cell shall show broadband characteristic. The simulated beam from the reflector, due to spatial arrangements of the unit-cells, showed the fundamental mode of orbital angular momentum vortex beams. Experimental verification of fabricated prototype shows good agreement with simulated far-field results at 9.5 GHz, 10 GHz, 10.5 GHz, and 11 GHz which indicate a broadband characteristic.

Highlights

The scientific community accepted that use of high order modulation formats like WDM, PDM technologies are promising in addressing spectrum issues of the present and future communication systems
Compared to Multi Input Multi Output (MIMO) antennas,5 the probing into applications of orbital angular momentum (OAM) is in a preliminary state; which suggests researching the field of OAM antennas at RF and microwave
The phase required for ijth element in an array to produce OAM beam can be written as φij

Summary

INTRODUCTION

The scientific community accepted that use of high order modulation formats like WDM, PDM technologies are promising in addressing spectrum issues of the present and future communication systems. The orbital angular momentum (OAM) is such a mode basis.1 It has Terabits transmission capacity reported over both free space and optical fibers.. Metasurfaces based on generalized Snell’s law, hold promises for a paradigm shift in wireless communication. Such surfaces recently found designs for Mono-functional and multifunction applications like efficient polarization dependent wave manipulators and transmissive lenses.. Some recent works on OAM generation include: horn antenna fed planar reflective metasurface; Varactor based reflectarray elements for dual polarized vortex beam; PancharatnamBerry type phase element to design broadband metalens for converting semispherical incident plane wave to radio vortex beams; and many more. Simulated and measured results at 9.5 GHz, GHz, 10.5 GHz, and GHz suggest suitability of the proposed design for x-band OAM communication

Analysis of broadband meta-element phase

Phase quantization

MODELING AND SIMULATIONS OF QUANTIZED SIERPINSKI SUPERCELL

EXPERIMENTAL RESULTS

CONCLUSION