Double-sided split-step MM-wave Fresnel lenses: design, fabrication and focal field measurements

Abstract

Design, fabrication and focal field measurements of W-band Fresnel lenses to produce well-shaped Gaussian beams in the focal domain are presented. Two lenses, one of Teflon and another of Polyamide, have been compared in their performance with a double-sided Fresnel lens of different design, with full height of Fresnel steps. Experiments show that a good focusing ability of all the lenses is achieved. They produce the target beam according to the design. Yet, the lenses of split-step design are thinner, have lower insertion losses, and a greater focal depth as compared to more conventional Fresnel lenses.

Light-controlled photonics-based mm-wave beam switch

“…A similar positive shift δ f = +0.05GHz appears due to uncertainty of the angle of incidence of plane waves δθ = ±2deg and for the actual Gaussian beam incidence as compared to the plane waves [ Fig. 4(b)] when the beam neck radius at the structure aperture is w A = 24mm [5] (the aperture radius is R = 34mm). For comparison, the full width of transmission peak at the frequency f = 96.1 GHz [curve 1 in Fig.…”

“…The VNA (R&S ZVA24) is equipped with frequency extension head (ZVA-Z110) for W band operation. The bench is equipped with custom split-step dual-aspheric mm-wave Fresnel lenses [5] and a top-frame LED-array light source designed for the optimal operation of the setup [ Having the structures of high quality allowed us to observe optical switching of mm-wave beams with various light sources including 250 W infrared incandescent and 500 W halogen lamps, a set of a few 100 W LED arrays, and a stroboscopic photo-flash lamp. The LED arrays are found to be the most suited among the other sources considered since they could be used in a pulse mode and, though producing smaller peak power compared to the flash lamp, could generate shorter pulses (down to 100 ns according to specification) and provide a better control of power and timing characteristics (the other sources create a smaller response and cannot be placed close to the switch aperture).…”

Mm-Wave Dielectric Parameters of Magnesium Fluoride Glass Wafers

“…If the actual beam profile created by lenses [13] is introduced, the beam model applied to an empty holder reproduces the reference curves recorded in the experiments. The mismatch of reference measurements and simulations is about 0.2 dB, which is the same as the discrepancy between different measurements of reference signals.…”

“…The VNA (R&S ZVA24) is equipped with frequency extension heads (ZVA-Z110) for W-band operation. The bench is furnished with custom split-step dual-aspheric MM-wave Fresnel lenses [13] which refocus nearly Gaussian beams of conical corrugated horns [14] fed by the VNA heads as shown in Figure 2(b) in [15]. The lenses create near-Gaussian beams of the waist radius w A = 24 mm at the aperture of stainless-steel holder carrying a Bragg structure inside (the aperture radius is R A = 34 mm) [15].…”

Multilayer Grid Polarizers: Simulations for Millimeter Waves

“…The effect of smearing transmission peaks arises also due to the limited beam width in the MM-wave experiments with multilayer structures [36,37] when Gaussian beams are created by optical components such as lenses [41]. The effect can further be enhanced due to self-emerging instability and fracturing of shape of higher-order modes under the resonant conditions [38,42].…”