Abstract-Terahertz reflectarray as a polarizing beam splitter

Tiaoming Niu, Withawat Withayachumnankul, Aditi Upadhyay, Philipp Gutruf, Derek Abbott, Madhu Bhaskaran, Sharath Sriram, and Christophe Fumeaux  »View Author Affiliations

http://www.opticsinfobase.org/oe/abstract.cfm?uri=oe-22-13-16148

Optics Express, Vol. 22, Issue 13, pp. 16148-16160 (2014)
http://dx.doi.org/10.1364/OE.22.016148

A reflectarray is designed and demonstrated experimentally for polarization-dependent beam splitting at 1 THz. This reflective component is composed of two sets of orthogonal strip dipoles arranged into interlaced triangular lattices over a ground plane. By varying the length and width of the dipoles a polarization-dependent localized phase change is achieved on reflection, allowing periodic subarrays with a desired progressive phase distribution. Both the simulated field distributions and the measurement results from a fabricated sample verify the validity of the proposed concept. The designed terahertz reflectarray can efficiently separate the two polarization components of a normally incident wave towards different predesigned directions of ±30°. Furthermore, the measured radiation patterns show excellent polarization purity, with a cross-polarization level below −27 dB. The designed reflectarray could be applied as a polarizing beam splitter for polarization-sensitive terahertz imaging or for emerging terahertz communications.

© 2014 Optical Society of America

Abstract-Experimental demonstration of reflectarray antennas at terahertz frequencies

Tiaoming Niu, Withawat Withayachumnankul, Benjamin S.-Y. Ung, Hakan Menekse, Madhu Bhaskaran, Sharath Sriram, and Christophe Fumeaux »View Author Affiliations

http://www.opticsinfobase.org/oe/abstract.cfm?uri=oe-21-3-2875

Reflectarrays composed of resonant microstrip gold patches on a dielectric substrate are demonstrated for operation at terahertz frequencies. Based on the relation between the patch size and the reflection phase, a progressive phase distribution is implemented on the patch array to create a reflector able to deflect an incident beam towards a predefined angle off the specular direction. In order to confirm the validity of the design, a set of reflectarrays each with periodically distributed 360 × 360 patch elements are fabricated and measured. The experimental results obtained through terahertz time-domain spectroscopy (THz-TDS) show that up to nearly 80% of the incident amplitude is deflected into the desired direction at an operation frequency close to 1 THz. The radiation patterns of the reflectarray in TM and TE polarizations are also obtained at different frequencies. This work presents an attractive concept for developing components able to efficiently manipulate terahertz radiation for emerging terahertz communications.

© 2013 OSA