• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2005년도 춘계학술대회논문집
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• pp.346-349
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• 2005

The present study aims to design electrically and structurally effective antenna structures in order that the structural surface itself could become the antenna. The basic design concept is composite sandwich structure in which microstrip antenna is embedded and this is termed composite smart structure (CSS). The most important outstanding problem is that composite materials of structural function cannot be used without reducing antenna efficiency. Unfortunately, such materials have high electrical loss. This is a significant design problem that needs to be solved in practical applications. Therefore, the effect of composites facesheet on antenna performances is studied in the first stage. Changes in the gain of microstrip antenna due to composites facesheet have been determined. 'Open condition' is defined when gain is maximized and is a significant new concept in the design of high-gain antennas considering bandwidth in practical application. The open condition can be made with any thickness of outer facesheet by controlling its position. In the design of CSS, glass/epoxy composites and Nomex honeycomb were used with exploiting open condition. Experiments, confirm that the gain is improved (over 11 dBi) and the bandwidth is also as wide as specified in our requirements (over 10% at 12.2 GHz). With the open condition, wideband antenna can be integrated with mechanical structures without reducing any electrical performances, as confirmed experimentally here.

• 한국복합재료학회:학술대회논문집
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• 한국복합재료학회 2005년도 추계학술발표대회 논문집
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• pp.35-38
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• 2005

The Objective of this work was to design Composite Antenna Structures (CAS) and investigate impact behavior of CAS which was various curvature. This term, CAS, indicates that structural surface becomes antenna. Constituent materials were selected considering electrical properties, dielectric constants and tangent loss as well as mechanical properties. For the antenna performance, microstrip antenna layers inserted into structural layers were designed for satellite communication at the resonant frequency of 12.5 GHz and final demonstration article was. After making five kinds of curved CAS, which radii of curvature are flat, 200, 150, 100, 50 mm. The antenna performance changed in accordance with variation of curvature. The Reflection coefficient was independent of curvature but the gain decreased with the radius of curvature. The impact test equipment was Dyna-8250 drop weight tester. The impact characteristic in accordance with curvature is maximum absorb energy is same each other. The impact energy was 8.5 J. For various Impact energy test, five energy levels 3 J, 5 J, 7 J, 10 J, 20 J were used. The performance of impact damaged antenna was estimated by measuring the return loss and the radiation pattern. It was revealed that the performance of antenna was not related to the impact damage. Because the impactor did not damage the patch directly. CAS have good impact stability for the antenna performance.

• 한국복합재료학회:학술대회논문집
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• 한국복합재료학회 2005년도 춘계학술발표대회 논문집
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• pp.55-58
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• 2005

The present study aims to design electrically and structurally effective antenna structures in order that the structural surface itself could become the antenna. The basic design concept is composite sandwich structure in which microstrip antenna is embedded and this is termed composite smart structure (CSS). The most important outstanding problem is that composite materials of structural function cannot be used without reducing antenna efficiency. Unfortunately, such materials have high electrical loss. This is a significant design problem that needs to be solved in practical applications. Therefore, the effects of composites facesheet on antenna performances are investigated in the first stage and changes in the gain of microstrip antenna due to composites facesheet have been determined. ‘Open condition’ is defined when gain is maximized and is a significant new concept for the design of high-gain antennas considering bandwidth in practical application. The open condition can be made with the outer facesheet by controlling its position. In the design of CSS, glass/epoxy composites and Nomex honeycomb were used with exploiting open condition. Experiments, confirm that the gain is improved and the bandwidth is also as wide as specified in our requirements. With the open condition, wideband antenna can be integrated with mechanical structures without reducing any electrical performances, as confirmed experimentally here.

• 한국정보기술응용학회:학술대회논문집
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• 한국정보기술응용학회 2005년도 6th 2005 International Conference on Computers, Communications and System
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• pp.353-356
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• 2005

A loop RFID tag antenna and a dipole RFID antenna with a T-matching method have been designed. The characteristic of loop and dipole with T-matching antenna structures of RFID tag antennas have been studied. The impedance of different sizes of loop and dipole antenna structures are found. This paper shows parametric research of loop RFID antenna structure and RFID dipole antenna with T-matching method to match the impedance of commercially available RFID chips.

• 한국항행학회논문지
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• 제27권5호
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• pp.629-634
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• 2023

본 논문에서는 여러 종류의 부채꼴 구조를 조합한 슬롯을 이용한 소형 광대역 테이퍼드 슬롯 안테나 설계에 대하여 연구하였다. 테이퍼드 슬롯 안테나를 소형화하고 낮은 주파수에서 동작하도록 하기 위하여 접지면에 부채꼴 구조를 조합한 슬롯을 추가하였다. 각 부채꼴 구조가 추가될 때 입력 반사 계수와 이득 변화를 슬롯이 없을 때와 비교하여 최종 제안된 안테나의 소형화 설계 과정을 체계적으로 설명하였다. 제안된 부채꼴 구조를 조합한 슬롯을 이용한 소형 광대역 테이퍼드 슬롯 안테나를 RF-35 기판 상에 제작하여 특성을 시뮬레이션 결과와 비교하였다. 실험 결과, 전압 정재파비(VSWR; voltage standing wave ratio)가 2 이하인 대역은 2.59-11.39 GHz이고, 대역내에서 이득이 3.3- 7.0 dBi로 측정되었다. 제안된 소형광대역 테이퍼드 슬롯 안테나는 접지면에 슬롯이 없을 때와 비교하여 크기를 36.9% 소형화할 수 있다.

• ETRI Journal
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• 제45권4호
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• pp.581-593
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• 2023

This paper proposes four-ring slot resonator-based MIMO antennas of 75×150 mm² without and with CSRR structures in the sub-6-GHz range. These orthogonal-fed antennas have shown diverse characteristics with dual polarization. L-shaped parasitic structures have increased the isolation (i.e., >40 dB) in the single-element antenna over the band of 3.4 GHz-3.8 GHz. A set of three CSRR structures in the MIMO antenna reduced the coupling between antenna ports placed in an inline arrangement and enhanced the isolation from 12 dB to 20 dB and the diversity characteristics. The S-parameters of both MIMO antennas are measured and used to evaluate MIMO parameters like ECC, TARC, MEG, and channel capacity loss. The simulation results show the variations in the gain and directivity on exciting linear and dual polarizations. The diversity performance of the reported MIMO antennas is suitable for 5G applications.

• 한국복합재료학회:학술대회논문집
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• 한국복합재료학회 2002년도 춘계학술발표대회 논문집
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• pp.195-198
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• 2002

Two types of conformal load-bearing antenna structure (CLAS) were designed with microwave composite laminates and Nomex honeycomb cores, to give both structural rigidity and good electrical performance. One is 4$\times$8 array for Synthetic Aperture Radar(SAR) system and the other is $5\times2$ array for wireless LAN system. Design was based on wide bandwidth, high polarization purity, low loss and good structural rigidity. We studied the design, fabrication and structural/electrical performances of the antenna structures. The flexural behavior was observed under a 3-point bending test, an impact test, and a buckling test. Electrical measurements were in good agreement with simulation results and these complex antenna structures have good flexural characteristics. The design of this antenna structure is extended to give a useful guide for sandwich panel manufacturers as well as antenna designers.

• Journal of information and communication convergence engineering
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• 제16권3호
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• pp.197-202
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• 2018

This paper reveals the impact of the insertion of electromagnetic band gap (EBG) structures on the performance of circularly polarized (CP) patch-slot antenna with offset slot. Several optimizations are necessary to precise physical parameters in the aim to fix the resonance frequency at 3.2 GHz. The proposed antenna possesses lightweight, simplicity, low cost, and circular polarization ensured by two feeding sources to permit right-hand and left-hand circular polarization process (RHCP and LHCP). The measured results compared with simulation results of the proposed circularly polarized EBG antenna with offset slot show good band operations with –10 dB impedance bandwidths of 9.1% and 36.2% centered at 3.2 GHz, which cover weather radar, surface ship radar, and some communications satellites bands. Our investigation will confirm the simulation and experimental results of the EBG antenna involving new EBG structures.

• 대한전자공학회논문지TC
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• 제46권8호
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• pp.67-78
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• 2009

유전상수가 10인 기판에 mushroom 형태를 가지는 EBG 구조를 전 방향과 길이 방향으로 집적한 패치안테나의 방사 특성을 체계적으로 해석하였다. 기판이 두꺼워질수록 표면파가 더 많이 발생하여 EBG 구조가 패치 안테나의 입력 임피던스와 방사 패턴에 미치는 영향이 커지는 것을 볼 수 있었다 기판 두께가 3.2 mm, 1.6 mm, 0.8 mm 인 경우 EBG 구조와 패치 중심 사이의 거리가 각각 0.4 ${\gamma}_0$, 0.2 ${\gamma}_0$, 0.1 ${\gamma}_0$ 이상 되어야 EBG 구조가 패치안테나의 입력 임피던스에 영향을 거의 주지 않았다. 기판 두께가 3.2 mm, 1.6 mm, 0.8 mm 인 경우 EBG 구조를 각각 2 주기, 2 주기, 3 주기 이상 집적하면 표면파가 억제되어 전방 방사가 향상되었다. EBG 구조를 길이 방향으로 집적한 경우와 전 방향으로 집적한 경우 EBG 구조가 패치안테나의 방사 특성에 미치는 영향은 비슷하였다.

• Wind and Structures
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• 제4권4호
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• pp.353-366
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• 2001

With respect to serviceability, antenna masts should be designed so that wind-induced motion will not cause unacceptable lack of transmission for broadcasting users and wireless communication. For such antenna masts with directional radio transmission the serviceability limit state is predominantly governed by the tolerable change of the broadcasting angle of the mounted antenna assembly and therefore by the tip distortion of the mast. In this paper it will be shown that refinements of the present state of design of antenna masts are possible by using the statistics of extremes applied to extreme wind situations and by consideration of the statistical and reliability requirements given by the operator such as frequency and return period of passing the serviceability limit.