Experimental demonstration of reflectarray antennas at terahertz frequencies

Near- and far-field measurements of phase-ramped frequency selective surfaces at infrared wavelengths

“…31,32 Also, the absorptance can be affected by the thickness of the dielectric layer. 4,8 However, except for the middle size structure, all the remaining structures are detuned from resonance. So, overall we expect that the actual fabricated phase-ramped structures should show relatively low absorptance despite the relatively high absorptance at the fundamental mode, which is important for the performance as a reflectarray.…”

“…Previously, it was shown that this value is diminished by lower conductivities of the metal used as the FSS element, high loss tangent of the dielectric layer, or larger thicknesses of the dielectric layer, but phase ranges similar to this value have yielded good results as a reflectarray. 4,8,31,33 Also critical to the performance of a reflectarray of constant periodicity is the need to have a relative constant progressive phase change of the reflected incident beam between each size structure. 7,8,34 As shown in both plots in offnormal with a 10.6 lm wavelength incident wave.…”

“…4,8,31,33 Also critical to the performance of a reflectarray of constant periodicity is the need to have a relative constant progressive phase change of the reflected incident beam between each size structure. 7,8,34 As shown in both plots in offnormal with a 10.6 lm wavelength incident wave. Black, square points represent the dimensions corresponding to the fabricated structures in Fig.…”

“…This has been successfully demonstrated in the terahertz and visible regions of the electromagnetic spectrum where a relatively high percentage of the incident beam was deflected at a specific angle. [6][7][8] For example, phase-ramped structures optimized for terahertz frequencies have been constructed from gold patch elements of different sizes arranged in repeating rows of six elements from smallest to largest. 6,8 Each of the elements was designed to initiate a different phase shift of the incident beam upon reflection and when combined in an array would steer a beam away from the specular reflection direction.…”

“…[6][7][8] For example, phase-ramped structures optimized for terahertz frequencies have been constructed from gold patch elements of different sizes arranged in repeating rows of six elements from smallest to largest. 6,8 Each of the elements was designed to initiate a different phase shift of the incident beam upon reflection and when combined in an array would steer a beam away from the specular reflection direction. It was found that the incident beam could be deflected at an angle off specular reflection, but that the resulting angle was relatively sensitive to fabrication imperfections, which limited how closely it matched the simulated value for this angle.…”