Sok Kim

A theoretical model is introduced to evaluate the ultimate resolution of plasmonic lithography using a ridge aperture. The calculated and experimental results of the line array pattern depth are compared for various half pitches. The theoretical analysis predicts that the resolution of plasmonic lithography strongly depends on the ridge gap, achieving values under 1x nm with a ridge gap smaller than 10 nm. A micrometer-scale circular contact probe is fabricated for high speed patterning with hig

A shape memory polymer (SMP) has been intensively researched in terms of its exceptional reversible dry adhesive characteristics and related smart adhesive applications over the last decade. However, its unique adhesive properties have rarely been taken into account for other potential applications, such as robotic pick-and-place, which might otherwise improve robotic manipulation and contribute to the related fields. This work explores the use of an SMP to design an adhesive gripper that picks

In this paper, we present a novel signal processing method for video synthetic aperture radar (ViSAR) systems, which are suitable for operation in unmanned aerial vehicle (UAV) environments. The technique improves aspects of the system’s performance, such as the frame rate and image size of the synthetic aperture radar (SAR) video. The new ViSAR system is based on a frequency-modulated continuous wave (FMCW) SAR structure that is combined with multiple-input multiple-output (MIMO) technology, an

The small synthetic aperture radar (SAR) technology experimental project (S-STEP) mission aims to develop an innovative spaceborne SAR microsatellite as a constellation of 32 microsatellites featuring a high-resolution stripmap mode of 1 m. The S-STEP is a spaceborne SAR microsatellite technology demonstration program in which innovative approaches have been proposed and investigated for SAR payload system designs for improving the development speed, affordability, size and weight parameters, an

There are two kinds of FMCW waveform, which are slow-ramp FMCW and fast-ramp one. In some applications like automotive radar sensors, fast-ramp FMCW waveform is usually preferable for the improved target resolving capability in multi-target situation when compared with slow-ramp one. Usually fast-ramp FMCW waveform uses up or down chirps only. But, sometimes, the waveform has to be generated with up and down chirps alternatively due to hardware limitations. In this case, the computational load,

In this paper, we present a method for generating synthetic aperture radar (SAR) video from multiple-input multiple-output (MIMO) video synthetic aperture radar (ViSAR) systems, which are suitable for operation in unmanned aerial vehicle (UAV) environments. This technique allows the analysis of stationary targets and moving targets in the SAR video. ViSAR systems are advantageous for detecting slowly moving targets since they have higher frame rates than conventional SAR systems. The MIMO ViSAR

The ultimate resolution of plasmonic lithography using a ridge aperture is evaluated using a theoretical model by Jae W. Hahn and co-workers on page OP337. A circular contact probe with high positioning accuracy is fabricated to record high density line array patterns with a half pitch up to 22 nm. The model fits well with the experimental results for pattern depth and predicts the resolution of plasmonic lithography to be less than 10 nm.

Abstract Synthetic aperture radar (SAR) raw data simulation, operating under various scenarios, and realistic environments, are necessary for analyzing and verifying the performance aspects of SAR systems and the various algorithms used in them. In this article, we propose a method to simulate the raw data generated by multiple‐input multiple‐output video synthetic aperture radar (MIMO ViSAR) from a speckled scene, using beat frequency division (BFD) frequency‐modulated continuous wave (FMCW). U

There have been so many research works on the SAR (Synthetic Aperture Radar) image generation using EM (Electro Magnetic) simulation. Particularly, there are several dedicated S/Ws for SAR image generation and analysis. But, most of them are not available to the public due to the reason for defense and security. In this paper, we describe the generation of SAR images for a realistic target model using the general purpose EM simulator like FEKO and demonstrate its validity by processing the simul

Dry adhesives offer appealing advantages such as reusability and clean detachment, yet their performance is fundamentally constrained by the trade-off between adhesion strength and fracture toughness. In this work, we present adaptive bilayer dry adhesives that integrate a thin, compliant elastomeric polydimethylsiloxane (PDMS) surface with a stiff shape memory polymer (SMP) backing layer. While the SMP layer enables shape programming through its rubber-to-glass transition, the PDMS layer suppre