고려대학교 초고주파연구실은 기존의 전자파 주파수 대역은 물론
밀리미터파(30-100 GHz) 에서 테라헤르츠파(100-10000 GHz)까지도 포함하는 초 광대역에서 다양한 회로와 필드 분석과 관련된 연구를 수행하고 있습니다. 특히 최근에는 국방 및 정부의 지원과제를 통하여 테라헤르츠 대역의 최첨단 능동 집적회로의 설계 기술을 함양하고, 외국 공정기관을 통해 제작된 회로를 국내 유일의 분석기기를 통하여 측정 실험을 진행하는데 주력하고 있습니다. 이와 더불어 밀리미터 및 테라헤르츠 금속 도파관을 이용한 부품 모듈화에도 노력을 기울이고 있습니다.
한편 국방특화연구실과 같이 테라헤르츠에 특화된 국방 및 정부과제를 효율적으로 수행하고 관련 분석 장비를 관리하기 위해서 고려대 연구처 직속으로 테라헤르츠 연구소를 신설하였습니다.

300 GHz InP rectangular cavity antenna

270-GHz Radiator Module for Eight-Way Incoherent Power Combining of InP HBT Oscillators

W-Band Waveguide Module Design for Power Combining of Linear Microstrip Array

A Wide-band Multi-layer Antenna Design using Double Resonance

280-GHz rectangular cavity antenna integrated in an 80-μm InP substrate

Design and performance analysis of THz wireless communication systems for chip-to-chip and personal area networks applications

A broadband waveguide filter design using electromagnetic bandgap substrate covers

A terahertz wire-array antenna integrated on a 75-µm InP substrate

Narrow-beamwidth T-shaped monopole antenna fabricated from metamaterial wires

D-Band Linear Beamforming Array Module with Microstrip Taper-Slot Elements

Lens Packaging of InP Feed using 2-D Antenna Simulation

255-GHz InP HBT Power Amplifiers Using Custom-designed Two-finger Devices

이중공진을 사용한 적층기판용 광대역 안테나 설계

270-GHz HBT Oscillator Performanc Packaged in WR-3.4 Standard Waveguide

60 GHz reflection-type phase shifter using 0.13 µm CMOS body-floating switches

WR-3.4 InP HBT amplifier module with integrated wideband waveguide transitions

Dual‐band circular polarization square patch antenna for GPS and DMB

Microstrip array antennas packaged in metal fixture for 150 GHz beamforming applications

장거리 대용량 밀리미터웨이브 광대역 통신용 통합 시뮬레이터 구축에 대한 연구

On-Board Phased Array 구성을 위한 Printed Dipole Antenna 연구

논 문 투 고 신 청 서

H-Band InP HBT Oscillator Arrays Packaged in Single Oversize Waveguide Channel

A microstrip antenna using patch array resonator

W-Band 0.5-W Waveguide Module Utilizing Spatial Power Combining of Linear Amplifier Array

An X-band microstrip phase shifter using an electromagnetic bandgap backplane

270-GHz InP HBT Detector Modules Utilizing WR-3.4 Waveguide and Silicon Lens

20-Gb/s ON–OFF-Keying Modulators Using 0.25- m InP DHBT Switches at 290 GHz

Uniform-field over-mode waveguide for spatial power-combining applications

Characterization of antireflection absorber films using WR-3.4 waveguide fixtures

An LTE-band dual-antenna design with an enhanced antenna efficiency

Microstrip-line sensor for the estimation of the fluid level inside a closed metal pipe

A 325 GHz InP HBT differential-mode amplifier

A 275 GHz active vector-sum phase shifter

400 GHz HBT differential amplifier using unbalanced feed networks

위성통신용 Ka-band RF Front-End 통신 실험 및 시뮬레이션에 관한 연구

A microstrip phase shifter design using a switch-loaded ground plate

A 280-GHz InP DHBT receiver detector containing a differential preamplifier

Slow-Wave Microstrip Lines Using Ground Slots for Enhanced Impedance Control

Ka-대역 4 채널 위상 배열 수신 모듈 기반 저궤도 위성 군집 통신 수신단 설계

Kim, Moonil

0004 2. Description of the Related Art 0005 Recently, research into a transmission/reception system utilizing high frequency of a millimeter wave band has been actively conducted, and Such a millimeter wave frequency band has the potential of being utilized in various application fields such as short-range wireless communica tion, a car radar, an image system, and the like. 0006. In particular, it is anticipated that a market for a short-range wireless communication system using a 60 GHz broadband frequency and a car radar system having a 77GHZ band will be in high demand. 0007. In a product of the application fields, a transmission/reception IC chip is generally packaged with an external Substrate, and passive circuits including an antenna are fab ricated on the external circuit, and here, for a transmission/reception system having a millimeter wave frequency band Such as the product of the application fields …

Dielectric resonator array antenna

Desertification is a serious ecological, environmental, and socio-economic threat to the world, and there is a pressing need to develop a reasonable and reproducible method to assess it at different scales. In this paper, the Hogno Khaan protected area in Mongolia was selected as the study area, and a quantitative method for assessing land cover change and desertification assessment was developed using Landsat TM/ETM+ data on a local scale. In this method, NDVI (Normalized Difference Vegetation Index), TGSI (Topsoil Grain Size Index), and land surface albedo were selected as indicators for representing land surface conditions from vegetation biomass, landscape pattern, and micrometeorology. A Decision Tree (DT) approach was used to assess the land cover change and desertification of the Hogno Khaan protected area in 1990, 2002, and 2011. Our analysis showed no correlation between NDVI and …

Assessment of land cover change and desertification using remote sensing technology in a local region of Mongolia

(57) ABSTRACT A dielectric resonator antenna is disclosed that includes a multi-layer substrate on which a plurality of insulating layers and conductor layers are alternately stacked. The dielectric resonatorantenna also includes a first conductor plate that has an opening part on the upper portion of the top insulating layer of the multi-layer Substrate and a second conductor plate that is formed on the lower portion of the bottom insu lating layer from the first conductor plate. The insulating layer is formed with at least two stacked layers and is dis posed at a position corresponding to the opening part. The dielectric resonator antenna also includes a plurality of first metal via holes, a feeding part and a matching Substrate that is stacked on the opening part and is stacked with at least one insulating layer.

Dielectric resonant antenna using a matching substrate

Spatially explicit information on forest management at a global scale is critical for understanding the status of forests, for planning sustainable forest management and restoration, and conservation activities. Here, we produce the first reference data set and a prototype of a globally consistent forest management map with high spatial detail on the most prevalent forest management classes such as intact forests, managed forests with natural regeneration, planted forests, plantation forest (rotation up to 15 years), oil palm plantations, and agroforestry. We developed the reference dataset of 226 K unique locations through a series of expert and crowdsourcing campaigns using Geo-Wiki (https://www.geo-wiki.org/). We then combined the reference samples with time series from PROBA-V satellite imagery to create a global wall-to-wall map of forest management at a 100 m resolution for the year 2015, with forest …

Global forest management data for 2015 at a 100 m resolution

Bursaphelenchus xylophilus , the pine wood nematode (PWN) which causes pine wilt disease, is currently a serious problem in East Asia, including in Japan, Korea, and China. This paper investigates the hyperspectral analysis of pine wilt disease to determine the optimal detection indices for measuring changes in the spectral reflectance characteristics and leaf reflectance in the Pinus thunbergii (black pine) forest on Geoje Island, South Korea. In the present study, we collected the leaf reflectance spectra of pine trees infected with pine wilt disease using a hyperspectrometer. We used 10 existing vegetation indices (based on hyperspectral data) and introduced the green-red spectral area index (GRSAI). We made comparisons between non-infected and infected trees over time. A t -test was then performed to find the most appropriate index for detecting pine wilt disease-infected pine trees. Our main result is that, in most of the infected trees, the reflectance changed in the red and mid-infrared wavelengths within two months after pine wilt infection. The vegetation atmospherically resistant index (VARI), vegetation index green (VIgreen), normalized wilt index (NWI), and GRSAI indices detected pine wilt disease infection faster than the other indices used. Importantly, the GRSAI results showed less variability than the results of the other indices. This optimal index for detecting pine wilt disease is generated by combining red and green wavelength bands. These results are expected to be useful in the early detection of pine wilt disease-infected trees.

Hyperspectral analysis of pine wilt disease to determine an optimal detection index

Grassland plays a key role for the food security of China because of the large number of livestock raised in those areas. Thus, grassland degradation due to climate change and overgrazing is considered as one of the most severe environmental and economic threat for the future sustainable development of China. Photovoltaic water pumping systems for irrigation can play a fundamental role for the conservation of grassland areas. This paper investigates the geospatial distribution of the technically suitable grassland locations for the implementation of photovoltaic water pumping systems. The technically suitable grassland areas were taken as starting point to assess the optimal locations. The assessment of the optimal locations was conducted using a spatially explicit optimization model of renewable energy systems based on the cost minimization of the whole forage supply chain. The results indicate that the …

Suitable and optimal locations for implementing photovoltaic water pumping systems for grassland irrigation in China

In this paper, H-band (220-325 GHz) power amplifier (PA) integrated circuits (ICs) are presented using 250-nm InP HBT technology, where a cascode topology was adopted to achieve high gain and high output power. Three PAs were designed: PA1 was implemented with two-stage cascode HBTs, PA2 combined two PA1s, and PA3 combined four PA1s, by using Wilkinson couplers without isolation resistors. Electromagnetic simulations were carried out for the accurate design of passive circuits such as a microstrip line, a capacitor, and RF pads. The measured insertion loss of the RF pad and Wilkinson coupler was as low as 0.24 dB and 0.70 dB, respectively, at 300 GHz. The three PAs exhibited a measured gain higher than 15 dB with good return losses at 300 GHz. The output powers scaled well with total emitter area of the PAs. PA3 exhibited a maximum output power of 13.5 dBm at 301 GHz. To the best of the …

H-band power amplifier integrated circuits using 250-nm InP HBT technology

Jeju Island is managed intensively in terms of environmental and ecological aspect because of its extraordinary ecosystem types comprising numerous rare, protected flora and fauna. To depict rapid change of habitat status in Jeju Island, the InVEST Habitat Quality model has been operated and compared analytically with the Eco-Natural map. The Habitat Quality map of Jeju Island is turned out to have similar inclination with Eco-Natural map. We compared the average habitat quality value in each Eco-natural map class in Jeju Island and the habitat quality value of first second third grade and non-included area decreased as 0.95 0.76, 0.53 and 0.37 in eco natural map respectively. Compared to biodiversity map based on biological investigation, the result of the InVEST habitat quality model can be simply obtained by land cover map with threat and sensitivity data. Further studies are needed to make explicit coefficients for Jeju Island and Korean peninsula, then the Habitat Quality model could be applied to past and future scenarios to analyze extent of habitat degradation in time series to help decision makers.

Habitat quality valuation using InVEST model in Jeju Island

The present invention aims to provide a printed circuit board and manufacturing method thereof, for embedding an electronic component in a core member, which improve the stiffness and heat-releasing property of the core member, provide superior adhesion between the core member and the insulation layer, and allow stable embedding of the electronic component.

Printed circuit board and manufacturing method thereof

Aims This study aimed to develop radial growth models and to predict the potential spatial distribution of Pinus densiflora (Japanese red pine) and Quercus spp. (Oaks) in South Korea, considering topographic and climatic factors. Methods We used a dataset of diameter at breast height and radial growth estimates of individual trees, topographic and climatic factors in systematic sample plots distributed over the whole of South Korea. On the basis that radial growth is attributed primarily to tree age, we developed a radial growth model employing tree age as an explanatory variable. We estimated standard growth (SG), defined as radial growth of the tree at age 30, to eliminate the influence of tree age on radial growth. In addition, SG estimates including the Topographic Wetness Index, temperature and precipitation were calculated by the Generalized Additive Model …

Radial growth response of Pinus densiflora and Quercus spp. to topographic and climatic factors in South Korea

Terahertz (THz) communication is a promising technique for chip-to-chip communication and wireless personal area networks. In this paper, we present an experimental study and design to realize such THz communication systems. We develop two different chip sets for on-off-keying (OOK) modulation based THz transceivers which include carrier generators, modulators, THz amplifiers, and baseband amplifiers. Specifically, the first chip set integrates the circuit blocks for the OOK modulation without the THz amplifier for short-range communication. In addition, the second chip set design includes the THz amplifier modules to extend the coverage of transmission. For these two chip sets, we experimentally demonstrate the feasibility of the wireless communication at THz frequency bands and assess performance using the bit error rate (BER) analysis. We estimate the BER by calculating the signal-to-noise ratio (SNR …

Deforestation in North Korea is becoming the epitome of the environmental change occurring in the Korean Peninsula. This study estimates the agro-environmental variables of North Korea’s croplands and analyzes the impact of deforestation using the GEPIC (GIS-based EPIC (Environmental Policy Integrated Climate)) model and time-series land cover maps. To identify the changes in agricultural quality under deforestation, wind erosion, water erosion, organic carbon loss, and runoff were selected as the agro-environmental variables having an impact on cropland stability and productivity. Land cover maps spanning the past three decades showed that 75% of the forests were converted to croplands and that 69% of all converted croplands were originally forests, confirming the significant correlation between deforestation and cropland expansion in North Korea. Despite limitations in the verification data, we conducted qualitative and quantitative validation of the estimated variables and confirmed that our results were reasonable. Over the past 30 years, agro-environmental variables showed no clear time-series changes resulting from climate change, but changes due to spatial differences were seen. Negative changes in organic carbon loss, water erosion, and runoff were observed, regardless of the crop type. On newly-converted agricultural lands, runoff is 1.5 times higher and water-driven erosion and soil organic loss are more than twice as high compared to older croplands. The results showed that the agro-environment affected by deforestation had an impact on cropland stability and productivity.

Impact of deforestation on agro-environmental variables in cropland, North Korea

(57) ABSTRACT A dielectric resonator antenna embedded in a multilayer sub strate is described. The dielectric resonator antenna includes a multilayer Substrate, a first conductive plate, a second con ductive plate, a plurality of first metal via holes, a feeding part configured to feed a dielectric resonator, and a conductive pattern part inserted into the dielectric resonator so that a vertical metal interface is formed in the dielectric resonator.

Dielectric resonator antenna embedded in multilayer substrate for enhancing bandwidth

The objective of this study was to examine the effect of thinning intensity on the diameter at breast height (DBH) and height growth of Japanese larch ( Larix kaempferi ) stands located in the Yangpyeong-gun region of central Korea. In addition, a growth model was developed from the thinning practice. Four sample plots were prepared separately and thinned at different intensities (0%, 10%, 20%, and 40% cutting based on the number of trees, respectively) in 1997. DBH and height of individual trees were measured independently in 1997 and 2009. The mean DBH for LT00, LT01, LT02, and LT03 increased from 12.0, 12.1, 12.0, and 12.7 cm in 1997 to 15.3, 16.1, 16.2, and 17.1 cm in 2009, respectively. In addition, the mean height for each plot increased from 11.9, 13.5, 13.6, and 12.0 m in 1997 to 17.0, 17.0, 17.1, and 18.1 m in 2009, respectively. Thinning intensity was found to have a significant positive effect on …

Impact of thinning intensity on the diameter and height growth of Larix kaempferi stands in central Korea

The present invention has been made in an effort to provide a dielectric waveguide antenna in which a matching unit having various structures for matching impedances between the dielectric waveguide antenna and air is formed in order to reduce reflection in an aperture of the dielectric waveguide antenna. According to a first preferred embodiment of the present invention, there is provided a dielectric waveguide antenna including: a dielectric waveguide transmitting a signal applied from a power feeder, a dielectric waveguide radiator radiating the signal transmitted from the dielectric waveguide to the air through a first aperture; and a matching unit formed in a portion of the dielectric waveguide and controlling a serial reactance and a parallel reactance to thereby perform impedance matching between the dielectric waveguide radia tor and the air, in order to reduce reflection generated in the first aperture during …

Dielectric waveguide antenna

0016. Accordingly, the present invention has been made keeping in mind the problems encountered in the related art and the present invention is intended to provide a dielectric resonator antenna embedded in a multilayer Substrate, which is easily fabricated using a single multilayer Substrate fabri cation process and in which changes in antenna characteris tics due to a fabrication error are small. 0017. An aspect of the present invention provides a dielec tric resonator antenna embedded in a multilayer Substrate, including a multilayer Substrate formed by alternately stack ing a plurality of insulating layers and a plurality of conductor layers, a first conductor plate having an opening and formed on a top of an uppermost insulating layer of the multilayer Substrate, a second conductor plate formed on a bottom of a lowermost insulating layer resulting from stacking at least two insulating layers downward from the first …

Dielectric resonator antenna embedded in multilayer substrate

This study identified the potential chemical accident occurrence in Korea by analyzing the spatial distribution of chemical factories and accidents. The number of chemical factories and accidents in 25-km 2 grids were used as the attribute value for spatial analysis. First, semi-variograms were conducted to examine spatial distribution patterns and to identify spatial autocorrelation of chemical factories and accidents. Semi-variograms explained that the spatial distribution of chemical factories and accidents were spatially autocorrelated. Second, the results of the semi-variograms were used in Ordinary Kriging to estimate chemical hazard levels. The level values were extracted from the Ordinary Kriging result and their spatial similarity was examined by juxtaposing the two values with respect to their location. Six peaks were identified in both the factory hazard and accident hazard estimation result, and the peaks …

Chemical accident hazard assessment by spatial analysis of chemical factories and accident records in South Korea

The Maubesi Nature Reserve (MNR) is a protected lowland area in eastern Indonesia that mainly consists of mangrove forest. The objective of this paper was to demonstrate a simple technique to visualize and quantify the change in mangrove area using a 3-year dataset of Landsat TM images acquired in 1989, 2003 and 2009. The normalized difference vegetation index (NDVI) was calculated to determine high and low vegetation biomass in each image. Each NDVI extracted by Landsat image in 1989, 2003 and 2009 was assigned to red, green and blue (RGB) color, respectively, and then combined to make color composites. Additive color theory was applied to interpret mangrove changes within the MNR area on the RGB-NDVI color composite. Changed areas were quantified by performing an unsupervised classification on the RGB-NDVI image with 45 classes that were grouped into eight major mangrove …

RGB-NDVI color composites for monitoring the change in mangrove area at the Maubesi Nature Reserve, Indonesia

Natural regeneration in forest management, which relies on artificial planting, is considered a desirable alternative to reforestation. However, there are large uncertainties regarding the natural regeneration processes, such as seed production, seed dispersal, and seedling establishment. Among these processes, seed dispersal by wind must be modeled accurately to minimize the risks of natural regeneration. This study aimed to (1) review the main mechanisms of seed dispersal models, their characteristics, and their applications and (2) suggest prospects for seed dispersal models to increase the predictability of natural regeneration. With improving computing and observation systems, the modeling technique for seed dispersal by wind has continued to progress steadily from a simple empirical model to the Eulerian-Lagrangian model. Mechanistic modeling approaches with a dispersal kernel have been widely used and have attempted to be directly incorporated into spatial models. Despite the rapid development of various wind-dispersal models, only a few studies have considered their application in natural regeneration. We identified the potential attributes of seed dispersal modeling that cause high uncertainties and poor simulation results in natural regeneration scenarios: topography, pre-processing of wind data, and various inherent complexities in seed dispersal processes. We suggest that seed dispersal models can be further improved by incorporating (1) seed abscission mechanisms by wind, (2) spatiotemporally complex wind environments, (3) collisions with the canopy or ground during seed flight, and (4) secondary dispersal, long …

Seed dispersal models for natural regeneration: A review and prospects

Embodiments of the invention provide a dielectric waveguide antenna including a dielectric waveguide transmitting a sig nal applied from a power feeder, a dielectric waveguide radia tor radiating the signal transmitted from the dielectric waveguide to the air through a first aperture, and a matching unit formed in a portion of the dielectric waveguide and controlling a serial reactance and a parallel reactance to thereby perform impedance matching between the dielectric waveguide radiator and the air, in order to reduce reflection generated in the first aperture during the radiation of the signal through the first aperture. Reflection in the aperture is reduced through the matching unit having various structures, thereby making it possible to improve characteristics of the dielectric waveguide antenna.

초고주파연구실

교수님 소개

김문일

연구실 소개

연구실 키워드

알럼나이가 간 회사

연구실 지원 방법

대우 조건

연도별 논문 인용수

저널 & 학회 논문 출판 수

연구실 논문 목록

On-Board Phased Array 구성을 위한 Printed Dipole Antenna 연구

W-Band 0.5-W Waveguide Module Utilizing Spatial Power Combining of Linear Amplifier Array

270-GHz InP HBT Detector Modules Utilizing WR-3.4 Waveguide and Silicon Lens

연구실 보유 특허

대학별 입시끈

우리 연구실 모집

교수님 소개

김문일

연구실 키워드

알럼나이가 간 회사

연구실 지원 방법

대우 조건

연도별 논문 인용수

저널 & 학회 논문 출판 수

연구실 논문 목록

On-Board Phased Array 구성을 위한 Printed Dipole Antenna 연구

W-Band 0.5-W Waveguide Module Utilizing Spatial Power Combining of Linear Amplifier Array

270-GHz InP HBT Detector Modules Utilizing WR-3.4 Waveguide and Silicon Lens

연구실 보유 특허

최근 3년간 연구실적 높은 연구실

대학별 입시끈

우리 연구실 모집