Design of a Wideband Coupled Feed Dipole Antenna for PCL Array Systems

왕성식,박준식,심홍석,추호성 대한전기학회 2020 Journal of Electrical Engineering & Technology Vol.15 No.5

This article proposes the design of a wideband coupled feed dipole antenna for Passive Coherent Location (PCL) systems. The proposed antenna consists of an internal direct feed dipole and an external coupled feed dipole. This coupled feed mechanism, which is often used in microstrip patch antennas, is applied to the dipole element for a wide matching bandwidth. To verify the operating principle of the proposed antenna, an equivalent circuit model is investigated along with some parametric studies of the coupling eff ect. The proposed antenna is then extended to an eight-element uniform circular array to confi rm the beamforming performance for PCL systems. The results demonstrate that the coupled feed dipole element is more suitable to enhance the matching bandwidth compared to a conventional dipole antenna

Design of S/X-Band Dual-Loop Shared-Aperture 2×2 Array Antenna

왕성식,장도영,김영완,추호성 한국전자파학회 2022 Journal of Electromagnetic Engineering and Science Vol.22 No.3

This article proposes the S/X band dual-loop shared-aperture 2 × 2 array antenna, which is constructed using a unit-cell having one Sband element stacked on 3 × 3 X-band elements. The unit-cell employs a coupled-fed dual-loop structure with a direct-feed pin on the upper loop to obtain the broadband matching characteristics and low manufacturing error. This radar configuration has the advantages of easy installation and low cost. In addition, the thin loop structure of the upper layer S-band element is optimized so that the S-band element has electromagnetic (EM) transparent characteristics in the X-band. The extended via cavity wall is also applied outside the nine Xband elements to block the mutual coupling effect among the X-band elements. To confirm the feasibility of the proposed array antenna, the beamforming performance and active reflection coefficient (ARC) characteristics of the fabricated array are examined in the S/X band.

덕트맵을 이용한 제주해안지역 이상 전파특성 분석

왕 성 식,임태흥,정영준,고민호,박용배,추호성 한국전자파학회 2019 한국전자파학회논문지 Vol.30 No.3

This study analyzes the propagation of the path losses between Jeju-do and Jin-do transceivers located in the coastal areas of Korea using the Advanced Refractive Prediction System(AREPS) simulation software based on the actual coastal weather database. The simulated data is used to construct a duct map according to the altitude and thickness of the trap. The duct map is then divided into several regions depending on the altitude parameters of Tx and Rx, which can be used to effectively estimate the abnormal wave propagation characteristics due to duct occurrence in the Jeju-do coastal area. To validate the proposed duct map, two representative atmospheric index samples of the weather database in May 2018 are selected, and the simulated path losses using these atmospheric indices are compared with the measured data. The simulated path losses for abnormal conditions at the Rx point at Jeju-do are 167.7 dB and 192.3 dB, respectively, which are in good agreement with the measured data of 164.4 dB and 194.9 dB, respectively.

발사체 주변환경에 의한 전파산란특성 예측 연구

장도영,왕성식,김춘원,박용배,추호성 한국전자파학회 2022 한국전자파학회논문지 Vol.33 No.6

본 논문에서는 발사체와 제어동 간의 텔레메트리 통신이 이루어질 때, 발사체 주변환경에 의한 전파특성을 예측하는방법을 제안한다. 발사체 주변 전파환경 분석을 위해 지형 및 건물을 실제와 유사하게 모델링하고, 이를 전파해석 도구에 반영해 통합 시뮬레이션 모델을 구축한다. 통합 시뮬레이션 모델을 사용하여, 발사체(송신)와 제어동(수신) 사이의전파 경로를 직접경로와 간접경로로 구분하여 분석하였을때, 지형지물에 의해 간접경로로 입사되는 신호는 직접경로로입사되는 신호 대비 7.6∼8 dB 낮은 것으로 확인되며, 구조물에 의한 영향이 지형 대비 더 큰 것으로 관측되었다. 분석결과를 검증하기 위해, 한국나로우주센터에서 송․수신기 사이의 전파손실을 측정하고, 이를 시뮬레이션과 비교분석하였다. 송신전력이 20 dBm일 때, 주파수 대역과 송신 위치에 따라서 수신전력은 최소 —77.3 dBm, 최대 —70.5 dBm으로잘 일치하는 것을 확인하였다.

고층기상에 따른 AESA 레이다의 전파특성 분석

임태흥(Tae Heung Lim),왕성식(Sungsik Wang),고진원(Jinwon Ko),고민호(Minho Go),서철헌(ChulHun Seo),추호성(Hosung Choo) 대한전자공학회 2019 전자공학회논문지 Vol.56 No.1

본 논문에서는 AREPS(Advanced Refractive Effects Prediction System) 시뮬레이션을 사용하여 공대공 AESA 레이다 전파특성 및 표적 탐지를 위한 경로손실 값을 분석하였다. 국내 도심 지역의 지형 정보를 반영하고 실측 대기 특성을 기반으로 한 trilinear 수정 대기 굴절률을 모델링하여, normal, surface duct, elevated duct, combined atmospheric condition 대기에 대한 네 가지 시나리오를 설정하였다. 또한, zx-plane에서 4.4°의 HPBW와 35.7dB의 SLL을 가지는 AESA 레이다 배열안테나의 방사패턴을 적용하여 네 가지 시나리오에 따른 경로손실 값을 도출하였다. 고도 5000 m에 위치시킨 AESA 레이다를 전면 방향으로 조향 하였을 때, combined condition에서 150 km 거리의 경로 손실 값이 171 dB로 계산되어 전면방향으로 표적 탐지 성능이 저하되는 결과를 확인하였다. Combined atmospheric condition의 대기 상태에서 trap의 높이와 두께를 변화시키며 고도 5000 m의 전면방향 표적 위치에 대한 경로손실을 분석하였으며, trap이 발생한 높이 h2가 AESA 레이다 위치와 유사한 4800 m부터 5200 m까지 위치할 때 표적탐지 성능이 많이 열화되는 것을 확인하였다. In this paper, we analyzed the radar wave propagation characteristics for air-to-air AESA radars and calculated the path loss for estimating target detection performance using Advanced Refractive Effects Prediction System (AREPS) simulation software. Four atmospheric scenarios of normal, surface duct, elevated duct, and combined atmospheric conditions were set up by using the trilinear modified refractivity model, including the terrain data of the urban area of Korea. In addition, we applied the radiation pattern of the AESA radar array antenna with HPBW of 4.4° and SLL of 35.7 dB in zx-plane to the path loss simulations with four atmospheric scenarios. When AESA radar located at a height of 5000 m is steered to the bore-sight direction, the path loss of 171 dB is obtained at a distance of 150 km in the combined atmospheric condition, which indicates that the target detection performance in the bore-sight direction may be degraded. In the combined atmospheric condition, the path losses according to the variation of the trap height and thickness were obtained when the target was located at the height of 5000 m. It is found that the target detection performance is drastically deteriorated when the height h2 resides between 4800 m and 5200 m, where the trap height is similar to the AESA radar altitude.

Prediction of Electromagnetic Wave Propagation in Troposphere Using Parabolic Equation and Two‑Dimensional Refractivity

Seongro Choi,허준,김창성,왕성식,추호성,박용배 대한전기학회 2020 Journal of Electrical Engineering & Technology Vol.15 No.3

In this paper, an analysis method of electromagnetic (EM) wave propagation in the troposphere is proposed using the parabolic equation (PE) and the actual two-dimensional modifed refractivity (M-unit), that is, range and height dependent M-unit. Discrete Mixed Fourier Transform (DMFT) based PE method is used, and the validation is conducted using AREPS which is developed by the Space and Naval Warfare System Center of US NAVY. The M-units at the National Typhoon Center (NTC) in Jeju-island and meteorological station in Heuksan-island, South Korea are calculated using actual meteorological data. Then, two-dimensional M-unit is estimated using linear interpolation of M-unit at each position. The path loss between NTC and Heuksan-island is analyzed using the three types of M-unit data, Heuksan-island only, NTC only, and linear interpolation. The efect of two-dimensional M-unit on the EM wave propagation when considering long-range problem is discussed.

격리도 및 내구성이 개선된 X대역 이중루프 배열 안테나 설계

장도영(Doyoung Jang),왕성식(Sungsik Wang),주정명(JoungMyoung Joo),추호성(Hosung Choo) 한국전자파학회 2021 한국전자파학회논문지 Vol.32 No.8

본 논문에서는 격리도 및 내구성을 고려하여 via cavity 구조를 적용한 적층형 X대역 이중루프패치 배열안테나를 제안한다. 제안된 안테나는 방사체의 크기를 줄이고 대역특성을 향상시키기 위해 간접급전구조를 포함하는 이중루프패치안테나를 개별소자로 사용한다. 또한, 내구성이 좋으면서도 격리도 특성을 개선시킬 수 있는 via cavity 구조를 포함하고 있다. 제안된 안테나의 검증을 위해 측정결과를 FEKO, CST, HFSS을 사용한 시뮬레이션 결과와 비교하였고, 제안된 안테나가 X대역에서 정재파비 3:1 이하로 동작함을 확인하였다. 또한 안테나를 3×3배열했을 때, 스캔 영역(0°<θ< 90°, 0°<φ<360°)에 대해서 배열안테나의 능동정재파비를 조사한 결과, 모든 조향 방향에서 3.7 이하의 능동정재파비가 나타나는 것을 확인하였다. Here, we propose an X-band dual-loop patch array with improved mutual coupling and durability. To reduce the radiator size and improve the bandwidth characteristics, individual elements of the proposed array antenna employ a dual-loop patch antenna that includes an indirectly fed structure. The proposed antenna includes a via cavity structure, which is advantageous for improving the isolation characteristics durability. To verify the performance of the proposed antenna, the measurement results are compared to the simulation results using FEKO, CST, and HFSS. The subsequent results demonstrate that the proposed antenna operates in the X-band with a VSWR less than 3:1. We also examine the VSWR in the scan range (0°<θ< 90°, 0°<φ< 360°) of the 3 × 3 array antenna, which exhibits active VSWRs less than 3.7 in all scan directions.