Earticle

This paper presents the design of a palm-sized metamaterial antenna system having reconfigurable polarization as well as dual-band characteristics. Basically, three antennas are laid by 45 degrees in order and excited by a compact metamaterial dual-band power-divider of the in-phase outputs, and the radiated fields of the antennas are mixed to turn the vector of the polarization to another. The validity of the proposed method is verified by observing the in-phase outputs from the odd-numbered power-dividing device for both 900 MHz and 2.4 GHz, and checking the changeable polarization with the antenna gain over 2 dBi for all the polarizations.

본 논문에서는 본 논문에서는 GPS 주파수 블록 중 L1블록인 1.575GHz에서 동작하는 GPS 수신 안테나를 설계하였다. 기존 GPS 수신 안테나는 고정·광역빔으로 차량이나 탑재체에서 이동할 경우 빔의 적응성이 다소 떨어지는 단점을 보인다. 이를 보완하기 위하 여 안테나의 이득을 높이고 전기적 위상을 조절해 빔을 조향할 수 있도록 하여 빔의 적응성이 생기도록 하였다. 설계한 안테나는 마이크로스트립 패치 안테나로서 방사소자를 배열형태로 확장하여 이득을 높이고 이에 CRLH 위상변위기를 결합하여 각 방사소자 에 위상차 급전이 가능하도록 하였다. 또한 제시된 CRLH 위상변위기는 단일 모델에서 가변 C의 조정으로 여러 가지 위상출력이 가능하도록 설계하여 버랙터 다이오드와 결합시 실시간으로 빔을 조정할 수 있어 항 재밍 기능도 갖출 수 있음을 보였다.

This paper presents an approach to enable a typical GPS receiver to be much less susceptible to intentional disruption such as jamming and change in link environment. In order for the GPS receiver to cope with jamming and to get adaptivity, a 4x4 beamforming antenna is designed using metamaterials. The design results show the antenna gain much higher than 5 dBi and the movable beam.

본 논문에서는 425 MHz에서 동작하는 저궤도 큐브위성 탑재용 메타물질형 안테나를 연구하였다. 원거리 무선통신 네트워킹의 중요 성과 위성의 역할이 대두되고, 큐브위성과 같은 자신만의 위성을 저가로 개발 보유를 희망하는 대학교나 개인들이 늘어감에 따라, 구조의 소형화 기술이 필요하다. 위성의 외부 공간을 많이 차지하는 것이 안테나 크기이므로, 경량화 목적으로 탑재용 소형 안테나의 설계하였다. 제안된 메타물질형 저자세 안테나의 경우 일반 패치안테나와 달리 0차 공진을 만들어 냄으로서, 전방향성 방사패턴을 만들어낸다. 또한, 제안된 안테나의 위성내부의 시스템 결합에 따른 전기적 특성변화를 확인하기 위해, 급전부를 대표하는 UHF 도 파관 대역통과 여파기와 연결하여 성능을 검증하였다. 모노폴과 메타물질형 저자세 안테나의 성능이 서로 비교된다.

In this paper, we suggest a design method of a metamaterial-based low-profile antenna working at 425 MHz for LEO/Cube satellites. Satellites play an important role in linking th remote nodes in a wireless communication network and covering wide areas of the globe. Especially, an increasing number of universities or individuals aspire having their own satellites and build low-budget structures such as cube satellites in LEO and the ways to reduce the sizes of their satellites. Since the antenna occupies a major portion of the satellite surface, the antenna should be miniaturized for lighter weight. The proposed metamaterial low-profile antenna, unlike the conventional patch antenna, produces such a zeroth-order resonance to create an omnidirectional radiation pattern. Also, it is connected to a UHF waveguide bandpass filter as the feeding system to examine the possible change in the situation that the antenna is combined with the system. The performances of the monopole and proposed metamaterial antennas are compared to one another.

Locally resonant metamaterials (LRMs) are artificial periodic structures that effectively suppress elastic wave propagation within specific frequency bands, known as bandgaps, by utilizing local resonance phenomena of embedded mass-spring resonators.​ Conventional LRMs, however, are limited by fixed bandgap characteristics once fabricated, necessitating re-fabrication or complex processing for any frequency adjustment. This study proposes a novel, tunable bandgap LRM architecture constructed from readily available, off-the-shelf mechanical components: a plastic bolt serving as the stiffness element and a changeable steel square nut as the mass element. Numerical analyses, employing Bloch-Wave theory for dispersion curve calculations and finite element methods for frequency response function (FRF) simulations, validate the systematic tunability of the bandgap. Specifically, by simply adjusting the nut's position along the bolt, the bandgap's central frequency and bandwidth can be effectively modulated without re-machining. Experimental validation on an 8x8 finite array structure confirms the formation and adjustable nature of these bandgaps, demonstrating a consistent shift in the bandgap frequency range in response to nut position changes, which aligns well with numerical predictions. This approach offers a practical, low-cost, and easily manufacturable solution for vibration mitigation, enabling on-site adaptable designs for targeted frequency ranges.

본 논문은 메타물질이 은폐 성능을 극대화할 수 있는 차세대 스텔스 기술의 핵심 소재로 부상함에 주목한다. 사례 분석을통해 스텔스 기술의 전략적 가치를 고찰하였으며, 메타물질 기반 스텔스 기술의 군사작전상 기대효과를 전장영역별로 분석하였다. 또한 국내 기술수준을 바탕으로 국방 R&D 예산 확보, 전문 인력 양성, 기반 인프라 조성의 세가지 측면에서 발전방안을 제시하였다. 차세대 스텔스 기술확보를 위해 미래전장 환경에 부합된 기술혁신을 지향해 미래도전국방기술개발 예산을 점진적으로 확대해 나가야 하며, 과학기술전문사관 및 국방첨단과학기술사관학교 제도 등 석사급 이상 전문 인력의 연구 방향을 지정해 효과적으로 활용해야 한다. 또한 활발한 기술 연구를 위해 각종 협의회, 연구센터, 학회 등이 마련되어 학제간, 산학연 주체간, 민-군간 네트워크를 공고히 해야 한다.

This paper highlights the emergence of metamaterials as a core material of next-generation stealth technology, capable of maximizing concealment performance. Through case analyses, this paper explores the strategic value of stealth technology and assesses the operational implications of metamaterial-based stealth technology across various battlefield domains. this paper assesses the current state of stealth technology in South Korea and proposes development strategies in three key areas: securing national defense R&D funding, cultivating advanced personnel, and establishing infrastructure. To secure next-generation stealth capabilities aligned with future battlefield environments, it is essential to gradually increase investment in future-oriented defense technology innovation. Moreover, the research directions of advanced personnel with master's degrees or higher—such as Researh Officers for National Defense and Korea National Defense Advanced Science and Technology Academy—should be clearly defined and effectively utilized. Finally, a robust network encompassing interagency councils, research centers, academic societies, and civil-military partnerships must be established to promote interdisciplinary and cross-sector collaboration in stealth technology development.

The multi-local resonance metamaterial is based on the local resonance mechanism of resonators, effectively blocking wave propagation within multiple resonant frequency ranges, a phenomenon known as band gaps. In practical applications for vibration reduction, the goal is to achieve wide-band vibration attenuation at low frequencies. Therefore, this study aims to improve the vibration reduction performance of multi-local resonance metamaterials by lowering the band gap frequency and expanding the band gap width. To achieve this, an objective function was formulated in the optimization problem, considering both the frequency and width of the band gap, with the geometric shapes of the multiple local resonators selected as design variables. The Sequential Quadratic Programming (SQP) technique was employed for optimization. The results confirmed that the band gap was generated at lower frequencies and that the band gap width was expanded.

We designed an antenna structure with the circular polarization metamaterial superstrate which increases the directivity of the primary antenna as a lens. The metamaterial superstrate removes the necessity of the array antenna and complicated feed. Plus, it provides the Fabry-perot cavity with the circular polarization. With regard to the primary antenna, a CRLH antenna is adopted to have the size-reduction from the conventional half-wavelength patch antenna

Satellite communication has reached a turning point in transmitting data quickly and receiving signals clearly in faraway places. This paper presents a metamaterial-based antenna for distant and military applications that overcomes restrictions and performs unmatched. This project explores metamaterials to create a unique antenna. Expect to be astounded by its power to bend electromagnetic waves, miniaturize, and change our relationship with the universe. The feeding mechanism of this antenna is a modified co-planar waveguide. At 5.6 GHz, the proposed antenna unit cell measures 0.076 , making it small thanks to its MTM characteristic. CP radiation is made when two orthogonally polarized modes are stimulated at the same time and two composite right- and left-handed transmission line unit cells are placed orthogonally. Reduced size, increased bandwidth, and improved Learn how this discovery opens new doors for high-resolution photography, broadband internet, and space exploration. One nanostructure that makes up a metamaterial is the Split Ring Resonator (SRR). SRR dimensions must be smaller than the resonance wavelength, making them crucial for near-infrared and optical responses. This effort examined nanoscale SRR characteristics in the infrared and visible ranges. SRRs composed of aluminum (Al) and gold (Au) were produced on silicon and silica substrates using electron beam lithography (EBL). The proposed structure consists of a microstrip-line-supplied SRR, a parasitic patch that is perpendicular to the ground plane, and two via holes connected by two split rings that feed the patch indirectly. Choosing the right material parameter for all such antennas depends on the planned structure. Fabrication and testing of the antenna matched simulations. Dimensions: 23.7 mm × 16.2 mm × 1.6 mm; substrate dielectric constant: 4.4. Experimental data are detailed and compared to analytical calculations. Simulation results show that metamaterials have negative permittivity and permeability in a certain frequency range, which can be predicted by an analytical method. Simulations indicated eight BRS, WiMAX, radar, and mobile phone resonance frequencies. Radiation is dipole-like in the omnidirectional in the H-plane and E-plane. 10 dB return loss and 3 dB axial ratio bandwidths are 38.6.7% and 8.1%, respectively.

본 논문에서는, 오프셋 카세그레인 반사판 안테나가 물리적 크기의 증가없이 Ku와 Ka 이중대역 신호를 다룰 수 있는 구조로 설계된 다. 계산시간 및 구현비용을 고려하여, 주반사판 대신에 부반사판에 Ka대역 신호는 반사시키고 Ku대역은 통과시키는 주파수 선택성 을 부여한다. 쌍곡선 부반사판 표면의 주파수 선택표면은 8각형 금속 링을 위 아래로 둔 다층매질의 단위 쎌의 주기적 형태로 구성된 다. 정밀한 전자기 모의시험을 통해 제안한 구조가 19 GHz와 45 GHz에서 동작함을 확인한다.

In this paper, a design of an offset Cassegrain antenna is proposed for Ku and Ka dual-band without increasing the antenna size. For Efficiency of computation and implementation, the frequency selectivity surface (FSS) of reflecting the Ka-band signal and passing the Ku-band is provided for the sub-reflector instead of the main reflector. The proposed FSS hyperboloid sub-reflector is the periodic structure of a unit cell comprising octagon metal rings embedded in the multiple layers. The proposed design is verified for 19 GHz and 45 GHz bands by the use of precise electromagneitc-field simulations.

This Paper serve as investigation for the different behaviors of resonant modes of the metamaterial loaded shorted Microstrip circular Patch antenna where the inner core is loaded with MNG(μ negative) metamaterial. The material DPS is outside of the MNG Core material. DPS is a double positive regular dielectric. MNG metamaterial loaded with circular patch is used for frequency tuning and dual band operation. Simulation has been performed by way of CST software program.

In this paper a new volumetric three dimension metamaterial design has been proposed. The structure consists of spherical balls of stainless steel and substrate of Bakelite. The structure is simulated from 1 to 20 GHz and show negative refractive in this range. Reflection and transmission coefficient (s-parameter) is used to calculate the effective permittivity and permeability of the structural. Refractive index of the structure is then calculated using effective permittivity and permeability of the structural. Due to negative refractive index it exhibits several unusual properties like focusing of light even with flat surfaces. This material can be easily incorporated with microstrip antennas to get highly directional beam patterns by using it as a substrate.

Wide range absorption is specially needed for different microtechnological applications along with microbolometers, photodetectors and coherent thermal emitters. Here we report, design of a wideband metamaterial absorber based on Titanium (Ti) and the analysis of its absorption and reflection characteristics. The structure of the absorber consists of two titanium layers spaced by a dielectric layer of refractive index 2. The simulation is done for analyzing its characteristics using finite difference time domain method (FDTD). The results show that the absorption occurs above 90 percent in the range 750 nm to 1200 nm while the reflection occurs below 10 percent. Overall absorption over the range (400 nm to 1500 nm) is found to be almost above 80 percent.

Metamaterial is the arrangement of "artificial" elements in a periodic manner providing unusual electromagnetic properties. This unusual property has made it an area of interest for last few decades. It has wide applications in antennas. Gain, directivity, bandwidth, efficiency, and many other parameters of microstrip patch antenna can be improved using metamaterials. In this review paper, we first overview the metamaterials, its types and then the application of metamaterials in Microstrip patch antennas over the last 13-15 years.

In this paper, the design and the analysis of the double square ring (DSR) metamaterial is presented, which is based on the equivalent circuit theory and the analysis of the distribution of the electromagnetic field. Based on the retrieval algorithm, the effect of the structural parameters on the effective permittivity and the effective permeability are proposed. The effective permittivity and the effective permeability of the designed DSR metamaterial are simultaneously negative in the range from 4.8GHz to 5.65GHz. A conventional microstrip antenna is designed as comparison, and the analysis of the microstrip antenna is not written in this paper for brevity. The superstrate is composed of an 44 array of the DSR metamaterial, and the novel antenna is consist of the conventional microstrip antenna and the superstrate. The effect of the distance between the superstrate and the antenna are simulated by HFSS software, and the novel antenna is proposed according to the analysis of the distance. The simulation results show that the gain of the novel antenna increased by 1.1dB, and the half power beam width decreased by 40.9°. Therefore, it is concluded that the performance of microstrip antenna can be improved by using DSR metamaterials.