Jae-Wook Lee

This paper presents the design, fabrication, and experimental validation of a K-band reflector antenna using a triaxially woven carbonfiber-reinforced silicone (CFRS) composite for small satellite applications. The CFRS surface was formed by curing a single lamina sheet into a parabolic geometry to optimize electromagnetic performance and structural integrity. To mitigate reflection loss caused by fiber discontinuities at high frequencies, a sealed triaxial woven fabric was employed, improving surface continuity and isotropy. Waveguide-based S-parameter measurements yielded an equivalent electrical conductivity of approximately 3,686 S/m and a reflection loss of about 0.2 dB at 20 GHz. Surface profiling confirmed sub-millimeter surface accuracy, and gain degradation due to surface errors was estimated to be less than 0.1 dB. A 0.6 m parabolic reflector achieved a boresight gain of 37.4 dBi at 20 GHz, showing close agreement with full-wave simulations incorporating the measured material and geometric properties. While a conceptual umbrella-type structure was designed to assess mechanical feasibility, the experimental prototype was constructed with a fixed feed support to prioritize precise electromagnetic verification under ground-based conditions. This work provides an experimental foundation for the development of lightweight CFRS-based reflector antennas for future small satellites in low earth orbit.

한국전자파학회논문지 (The Journal of Korean Institute of Electromagnetic Engineering and Science)

When an electronic device featuring an enclosure and an internal PCB is located inside a building, analyzing the coupling phenomenon resulting from external high-power electromagnetic waves at specific locations on the PCB using conventional commercial simulation tools requires significant computational resources. As the analysis frequency increases beyond several GHz, the number of mesh elements grows substantially, making full electromagnetic simulation practically infeasible. This paper proposes a spatially partitioned frequency-domain analysis method based on the Huygens’ box-based electromagnetic topology approach to overcome the limitations of conducting coupling analysis for small enclosures inside buildings. First, a Huygens’ box is assumed to contain the enclosure of the electronic equipment, and the coupling characteristics of the external electromagnetic waves incident through a window into the Huygens’ box are analyzed. Then, a separate Huygens’ box and enclosure are constructed to analyze the coupling effects at specific locations on the internal PCB. Additionally, a two-stage Huygens’ box is introduced to contain the PCB inside the enclosure, and the results are compared. Finally, the feasibility and validity of the proposed partitioned-recombination analysis method are verified by comparing its results with those of full-model simulations up to 10 GHz.

한국전자파학회논문지 (The Journal of Korean Institute of Electromagnetic Engineering and Science)

한국전자파학회논문지 (The Journal of Korean Institute of Electromagnetic Engineering and Science)

한국전자파학회논문지 (The Journal of Korean Institute of Electromagnetic Engineering and Science)

This paper analyzes the performance of the bistatic staring spotlight mode in a low-orbit satellite environment and then compares it with the performance of the monostatic staring spotlight mode. The staring spotlight mode provides high-resolution images by continuously stare at the target via azimuth beam steering. However, monostatic synthetic aperture radar (SAR) systems may not achieve the desired performance in this mode owing to the geometric limitations of performing missions using a single satellite. To overcome these limitations, a bistatic SAR system that uses two satellites is considered in this study. By using two satellites, uncertain ground structures can be handled with flexibility. Moreover, a strategically planned design for a bistatic SAR system can help achieve a wider range and better performance than a monostatic SAR system. By applying this design to the staring spotlight mode, a SAR system that offers both high-resolution images and good performance is proposed.

This paper proposes a non-destructive method for measuring the complex permittivity of thick slab specimens using the Improved Open Waveguide (IOW) method based on the NRW Method. Conventional methods, generally effective only for thin materials, face significant challenges in accurately measuring the complex permittivity of thick slab specimens. This study addresses the limitations of prior methods by applying a disambiguation technique under non-magnetic conditions. The accuracy of the proposed methods was validated through numerical analysis and experimental results. Specifically, Measurements were conducted on paper specimens of varying thicknesses and a concrete block. For the paper specimens, the results closely matched reference values obtained using the Split Cylinder Resonator (SCR) method, a widely used standard for thin specimens. For the concrete block, numerical analysis was used to validate the derived complex permittivity, confirming the reliability of the proposed methods. While the IOW method relies on numerical analysis, which increases processing time, it provides reliable and accurate measurements of complex permittivity, particularly for specimens where sample preparation is challenging.