77-GHz High-Gain Bull’s-Eye Antenna With Sinusoidal Profile

3-D-Printed 96 GHz Bull’s-Eye Antenna With Off-Axis Beaming

“…Thus, as observed in [23], at a sufficiently large number of periods, the increase of the gain for consecutive number of grooves will be negligible. This was also reported in [26] and very recently in [31]. P=3 P=4 P=5 P=6 P=7 P=8 P=0 P=1 P=2 P=3 P=4 P=5 P=6 P=7 P=8 P=0 P=1 P=2 P=3 P=4 P=5 P=6 P=7 P=8 P=0 P=1 P=2 P=3 P=4 P=5 P=6 P=7 P=8 P=0 P=1 P=2 P=3 P=4 P=5 P=6 P=7 P=8 P=0 P=1 P=2 P=3 P=4 P=5 P=6 P=7 P=8 P=0 P=1 P=2 P=3 P=4 P=5 P=6 P=7 P=8 P=0 Fig.…”

“…Therefore, an alternative explanation was put in terms of the leaky-wave theory [29], [30], complementing the plasmonic interpretation. These antennas have been demonstrated at millimeter-waves for automobile radar [31] and space research applications [7] as well as in the terahertz [32] and mid-infrared band for quantum-cascade lasers [33].…”

Additive manufactured millimeter wave off-axis bull's-eye antenna

“…It was chosen to include only P = 7 rings, as it was found to be a good tradeoff between size and gain. A higher gain is not necessarily obtained with an increasing number of periods, as reported in [7], [8], [14].…”

“…The metallization of the antenna was modelled as bulk Copper (σ = 5.8×10 7 S/m). The antenna follows a design process similar to previous antennas [7], [8] where a metallic slab is perforated by a central aperture, whose dimensions (s x × s y × s z ) fix the frequency at which the power, fed by a waveguide attached to the rear part, will be coupled to a TM surface wave. In this case, the slot's width (1.627 mm) and the height (0.470 mm) fix the operating transversal resonance and its Q-factor, whereas the slot's depth (0.77 mm) locates the longitudinal resonance at higher frequencies.…”

Study of Leaky Waves Responsible for Terahertz TE Extroardinary Transmission

“…Saturation in energy decay time occurs above 30 slits. Saturation in transmission is reached when the array is long enough that leaky waves have explored a large enough number of slits to re-emit all the energy associated with the mode, as with TM ET [10] [11]. The substantial difference in saturation decay times for the different dielectric thicknesses can be attributed to the previously mentioned threshold thickness, whereby a defined thickness is required for the grounded dielectric mode to be fully developed, allowing for efficient coupling to the mode.…”