A5085358071- Antenna Design and Optimization
- High Temperature Alloys and Creep
- Radar Systems and Signal Processing
- Electromagnetic Compatibility and Measurements
- Antenna Design and Analysis
- Nuclear Materials and Properties
- High-Temperature Coating Behaviors
- Microwave Engineering and Waveguides
- Advanced Photocatalysis Techniques
- Material Properties and Applications
- Surface Treatment and Residual Stress
- TiO2 Photocatalysis and Solar Cells
- Microstructure and Mechanical Properties of Steels
- Metal and Thin Film Mechanics
- Surface Treatment and Coatings
- Advanced Materials Characterization Techniques
- Aerogels and thermal insulation
- Erosion and Abrasive Machining
- Welding Techniques and Residual Stresses
- Intermetallics and Advanced Alloy Properties
- Advanced Antenna and Metasurface Technologies
Agency for Defense Development
2020
Defence Science and Technology Agency
2019
Korea Electric Power Corporation (South Korea)
2009-2018
Electric Power Research Institute
2009
본 논문에서는 편파 다이버시티를 구현하기 위한 바람개비 형태의 루프 안테나를 제안하였다. 제안된 안테나의 원주는 일반적인 소형 길이(<TEX>${\lambda}$</TEX>)보다 10배가 크나, 안테나와 같이 수평면에서 무지향성 패턴을 얻을 수 있다. 기생 사용을 통해 임피던스 정합 문제를 해결하고, 등가 회로를 제시하여 설계 의도가 수식적으로 설명될 있음을 보였다. 안테나는 2.6 GHz에서 설계, 제작되었으며 정재파비 2:1 이하를 기준으로 6 %의 대역폭, 분리도 15 dB, 이득 1.5 dBi의 시뮬레이션 결과를 나타내었고, 결과와 측정 결과가 잘 일치하였다. A windmill-shaped loop antenna is designed for polarization diversity. Its circumference almost 10 times that of a conventional small whose less than <TEX>${\lambda}/10$</TEX>...
To prevent the detection performance of radar systems from being degraded by interference signals appearing in side-lobe antenna, an additional blanking(SLB) antenna is often added and operated alongside main antenna. In this paper, SLB composed array elements within discussed. Using structural features digital active phased implies that no physically added. Optical channels are also employed to simultaneously form multiple beams for antennas. A structure cover all side-lobes pattern was...
본 논문에서는 유전 알고리즘을 이용한 광대역 부배열 최적화 설계에 대해 기술하였다. 먼저 무한 주기 구조의 삼각 배열을 이용하여 복사 소자를 설계하였다. 너치 소자로 정면 빔 조향 시 능동 반사 계수 -10 dB 이하를 만족하는 최대 및 최소 주파수 비가 약 2:1 정도로 특성을 가지고 있다. 이러한 배열 소자 1,100여개로 이루어진 안테나 최적화를 위해 이용하였다. 대조군인 규칙 구조와 비교해서 최적화(불규칙) 부엽 준위가 4.5-5.5dB 정도 개선되었음을 확인하였다. This paper specifies on optimized design of wide-band subarray using a Genetic Algorithm. First radiator was designed at triangle lattice infinite array structure. It is the notch type that has characteristic ratio between...
Recent advances in hardware have resulted the introduction of an integrated transmit/receive single chip that can not only transmit and receive RF(Radio Frequency) signals, but also perform analog to digital data conversion. This makes it easier develop element-level active phased array(DAPA) antennas. Owing that, there is increasing demand for radar applications, including multi-function radar. The transmitting(Tx) near-field measurement configuration applied verify performance traditional...
Herein, we describe the receiving (Rx) near-field measurement of digital active phased array antennas applicable to multifunction radars. Because structural differences with analog antennas, it is difficult apply conventional Rx test configuration. Therefore, have proposed a configuration suitable for arrays. In simulation, results are presented beam pattern distorted by leakage signal generated in near field and corrected these signal. After which, based on results, measured data reviewed....
The time dependent degradation of first-stage blades for gas turbine was investigated. First, Two used were prepared from the operating facilities, and their hours 25,000 52,000 hrs, respectively. Microstructural comparison coating surfaces showed that exposure to environment increased thickness TGO (Thermally Grown Oxide) β depletion region, then debonding spallation TBC (Thermal Barrier Coating) occurred finally. In case substrate, Ni-based superalloy, shape size γ' changed with increasing...
Leakage signals, inevitably generated during near-field measurement of a digital radar, affect the measured data samples. Although each leakage signal occurs at very low level, signals accumulate and have significant effect when converts into far-field beam pattern. In this study, we verified method that effectively eliminates through back projection from data. simulation, difference between characteristics noise was examined, simulated with mathematical modeling. Next, analyzed on antenna...