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Multiple reflections from electrically large hemispherical lens surfaces of lens-integrated antennas are investigated using an iterative Huygens’ integral approach. In particular for mmW- and THz-band applications, double-slot antennas on extended hemispherical high-resistivity Silicon lenses have been widely used due to the high Gaussisicity of their radiation/ reception patterns. Previous studies assumed an electrically-large lens and evaluated the antenna pattern using first-order physical optics approximation. Although this approach is fairly accurate for estimating the radiation pattern of such antennas, the reception pattern and the associated performance of receiving sensors need a more careful consideration due to the relatively large level of internal reflections from the concave boundary of the high index lens. Here, we present an iterative method to compute and study the effects of multiple reflections inside electrically large lenses. The rich nature of quasi-optical wave behavior is demonstrated through several examples corresponding to individual bounces of the incident, reflected, and transmitted waves from a double slot antenna.
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This content will become publicly available on July 24, 2026
Conformal Electrochemical Nanoimprinting of Silicon: Toward Bio‐Inspired Hierarchical Infrared Meta‐Optics
Abstract Nanostructured anti‐reflection metasurfaces for infrared lenses are designed for imaging in harsh environments such as dust (e.g., moon or battlefield), micrometeorites (e.g., Lagrange points), and high‐radiation fluctuations (e.g., Mars) with limited lifetimes. These multifunctional optical meta‐surfaces (MOMS) simultaneously deliver high thermal stability and anti‐fouling behavior due to their monolithic nature (e.g., no mismatch in the coefficient of thermal expansion), hydrophobicity, and low dust adherence. However, the incompatibility of inorganic semiconductor micromachining with non‐planar substrates has limited MOMS to polymeric and glass lenses. Here, a new method of conformal electrochemical nanoimprinting is presented to directly micromachine a nature‐inspired MOMS onto a silicon lens. Uniquely, stretchablegold‐coated patterned porous PVDF stamps are made by lithographically templated thermally induced phase separation (lt‐TIPS), which simultaneously embeds it with (i) interconnected porosity for promoting mass transport, (ii) HF‐resistance for increasing operational lifetime, and (iii) stretchable electronic nanocoatings (i.e., Au) that can catalyze the electrochemical process. In a demonstration of its hierarchical micromachining capability, a sharklet microscale pattern is successfully transferred to a silicon lens with anti‐reflective and hydrophobic properties. This work paves the way for MOMS’ extension onto inorganic semiconductors and IR lenses.
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- Award ID(s):
- 1944750
- PAR ID:
- 10640385
- Publisher / Repository:
- Wiley Blackwell (John Wiley & Sons)
- Date Published:
- Journal Name:
- Advanced Materials
- ISSN:
- 0935-9648
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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