Miniaturized LPDA Antenna for Portable Direction Finding Applications

Junho Yeo,Jong-Ig Lee 한국전자통신연구원 2012 ETRI Journal Vol.34 No.1

In this letter, a miniaturized log-periodic dipole array (LPDA) antenna operating from 1 GHz to 6 GHz is proposed for portable direction finding applications. To reduce the lateral size of an LPDA antenna, bow-tie elements and a top-loading technique are utilized and spacing factor is decreased to reduce the spacing between the LPDA elements. The proposed miniaturized LPDA antenna has the measured gain and front-to-back ratio ranging from 1.2 dBi to 3 dBi and from 7 dB to 22 dB, respectively.

The Impact Analysis of Urban Growth on the Environment using the Econometric Regional Impact Model

JunHo Yeo,Jung-In Lee,Jae-Geun Park 한국환경정책평가연구원 2005 한국환경정책평가연구원 연구보고서 Vol.2005/re-07 No.-

빠르게 변화하는 기술 및 인구통계, 중앙정부 및 지자체의 정책, 그리고 세계화의 영향 등은 지역 정책 입안자들로 하여금 지역 경제와 환경에 대한 정확한 정보 파악을 필요로 하고 있으며, 지역 경제 체계에 대한 상황에 맞는 정보의 필요성이 높아지면서 지역사회에 대한 영향을 측정할 명쾌한 모델 개발이 중요하게 되었다. 그러나 국내의 경우, 각 도시별로 미래 경제성장이 인구나 환경변수들에 미치는 영향에 대해서 구체적으로 계량화한 연구나 자료가 없는 실정이어서 총생산량 증가와 밀접한 관계가 있는 도시별 총고용량 증대, 즉 경제성장이 환경부문에 미치는 영향을 계량화할 분석방법에 대한 연구가 필요하였다. 이러한 필요성을 바탕으로, 본 연구에서는 국내의 주요도시별로 고용량의 변화가 환경변수(아황산가스 오염도, 이산화질소 오염도, 생활폐기물 발생량, 공장폐수 방출량)와 기타 인구, 경제변수들에 미치는 영향을 평가하였다. 분석방법으로는 투입산출모델(Input-Output Model)의 단점을 보완할 수 있는 연립방정식모델(Simultaneous Equation Model)을 이용하였고, 실제 영향분석을 위해서 추정된 연립방정식모델을 유도형방정식(Reduced Form Equation)으로 전환하여 분석에 이용하였다. 분석결과를 요약해 보면 다음과 같다. 7대 도시의 취업자수 평균 증가율은 29.94%이고 광주가 35.81%로 최고의 증가율을 보이고 부산이 21.97%로 최저의 증가율을 보이는 것으로 추정되었다. Impact analysis 결과 고용증대가 인구나 실업자 증가에는 별로 영향을 미치지 않고 노동 인구의 증가와 노동참여율에는 큰 영향을 미치는 것으로 나타났다. 고용량 증가가 SO2, NO2, 생활쓰레기 발생량, 공장폐수 방출량에 미치는 영향은 거의 없거나 아주 미미한 것으로 나타났다. 이러한 결과는 현실과도 부합되는 것으로 고용증대가 생활쓰레기 발생량이나 공장폐수 방출량에는 아주 미미한 증가효과를, 그리고 SO2 농도에는 아주 미미한 감소효과를 주는 것으로 나타났으나 그 효과는 극히 미미함을 알 수 있었다. 그러나, 본 연구에서 추정한 연립방정식모델로는 산업별 고용증대가 환경부문이나 노동시장부문에 미치는 영향을 파악하기가 어려운 점이 있다. 산업별 고용증대 효과를 분석하기 위해서는 외부 충격 변수로 전체 고용 증대가 아니라 특정한 산업의 고용증가를 이용해야 할 것이다. 또한 고용증대가 환경부문에 미치는 영향은 아주 미미한 것으로 나타났기 때문에 차후 연구에서는 도시의 GNP 성장이나 GDP 성장과 같은 변수들을 충격변수로 이용하여 분석해 보는 것도 의미있는 연구가 될 것으로 보인다. This study develops a regional econometric model to extend and complement standard local economic impact analysis for Korean cities. We use a static macroeconomic model to derive labor supply equations and environmental equations. The resulting empirical model is based on a cross- sectional econometric analysis of Korean cities. The use of the estimated econometric model is illustrated with a real job-growth scenario using the growth in jobs between 2000 and 2006 for each Korean city. We focus on the effect of job growth on the labor market, especially on the allocation of jobs between in-migration, in-commuting and the local resident labor force. The purpose of this research was to estimate the effect of employment changes between 2000 and 2006 on population, labor and the environment. In order to do this, we have determined the estimated value of the number of job holders in seven major cities in 2006 and added this to a reduced form equation as an external impact, to predict changes in the eight endogenous variables. It was estimated that the average increase number of the employed in the seven cities was 29.94%; Gwangju showed the highest increase rate of 35.81%, while Busan recorded the lowest, 21.97%. The results of impact analysis demonstrated that employment growth hardly affected population or affected a change in the number of unemployed, but it had a large influence on the labor force increase and participation rate. The employment growth had almost no effect on the amount of SO2, NO2, house wastes and factory wastewater. The results also accord with the actual situation, where employment growth caused a very minor increase in the amount of house wastes and factory wastewater, and a very slight decrease in the density of SO2; however, the effect was too little. Nonetheless, it is difficult to identify the effect of employment growth in each industry on the environment or labor market, by using the simultaneous equation model presumed in this research. In order to analyze the effect of employment growth by industry, the increase of employment in the relevant industry, rather than total employment growth, should be used as an external impact variable. Moreover, as the effect of employment growth on the environment has turned out to be insignificant, it will be meaningful to analyze the matter by using variables such as the GNP or GDP growth of a city as impact variables, in the future research.

Compact Microstrip-Fed Square Loop Antenna for DTV Applications

Yeo, Junho,Lee, Jong-Ig The Korea Institute of Information and Commucation 2016 Journal of information and communication convergen Vol.14 No.4

A design method for a compact square loop antenna fed by a microstrip (MS) line for indoor digital television (DTV) applications is proposed. The proposed antenna consists of a square loop, circular sectors, and an MS line. The square loop combined with circular sectors is printed on one side of a substrate, and a $75-{\Omega}$ MS line is printed on the other side. The circular sectors are used as a wideband balun or transition to connect the MS line and the square loop. A prototype of the proposed square loop antenna operating in the DTV band (470-806 MHz) is designed and fabricated on an FR4 substrate. Experimental results show that the proposed antenna has the desired impedance characteristics in the frequency band of 464-1,220 MHz (89.8%) for a voltage standing wave ratio (VSWR) of <2 covering the DTV band, and a broadside gain of 0.8-3.3 dBi in the DTV band.

Compact Dual-Band Half-Ring-Shaped Bent Slot Antenna for WLAN and WiMAX Applications

Yeo, Junho,Lee, Jong-Ig The Korea Institute of Information and Commucation 2017 Journal of information and communication convergen Vol.15 No.4

A compact dual-band half-ring-shaped (HRS) bent slot antenna fed by a coplanar waveguide for wireless local area network (WLAN) and worldwide interoperability for microwave access (WiMAX) applications is presented. The antenna consists of two HRS slots with different lengths and widths. The two HRS slots are connected through an arc-shaped slit, and the upper HRS slot is bent in order to reduce the size of the antenna. The optimized dual-band HRS bent slot antenna operating in the 2.45 GHz WLAN and 3.5 GHz WiMAX bands is fabricated on an FR4 substrate with dimensions of 30 mm by 30 mm. The slot length of the proposed dual-band slot antenna is reduced by 35%, compared to a conventional dual-band rectangular slot antenna. Experimental results show that the proposed antenna operates in the frequency bands of 2.40-2.49 GHz and 3.39-3.72 GHz for a voltage standing wave ratio of less than 2, and measured gain is larger than 1.4 dBi in the two bands.

Long Range UHF RFID Tag with a Rectangular Metallic Cavity Structure

Junho Yeo 한국전자파학회JEES 2010 Journal of Electromagnetic Engineering and Science Vol.10 No.3

A long range UHF RFID tag with a rectangular metallic cavity structure is proposed for various applications with metallic objects. The proposed tag consists of a rectangular metallic cavity structure and a folded dipole antenna which is located on top of the cavity. The tag is designed for Korean UHF RFID band(910~914 ㎒) and the bandwidth, which satisfies the-10 ㏈ input reflection coefficient requirement, is approximately 1.3 %(904~916 ㎒). Measurement demonstrates that the proposed tag shows long reading range up to 15 m when it is placed on a metallic plate.

Design of a Multiple Band-notched Wideband Circular Slot Antenna with Arc-shaped Slots

Yeo, Junho,Park, Cheol-Young Korea Society of Industrial Information Systems 2013 한국산업정보학회논문지 Vol.18 No.1

A design method to achieve multiple band-rejection characteristics in a wideband circular slot antenna is presented. First, a wideband circular slot antenna fed by a coplanar waveguide is designed to operate in the frequency range between 2.3 and 11GHz, which covers WLAN, WiBro, WiMAX, and UWB frequency bands. Next, resonant frequency variations of rejection bands are examined with respect to different slot locations and lengths when slots are inserted on the ground conductor and the circular patch of the antenna. When arc-shaped slots are placed close to the circular transition from a feeding part, multiple notch bands are obtained. In this case, a half of the guided wavelength of the first notch band corresponds to the slot length and other notch bands are integer-multiple of the first band. Single notch band can be obtained when the slot is located off the transition part. Based on this study, a wideband circular slot antenna with five band-rejection frequency bands at 2.45, 3.5, 4.9, 7.35, and 9.8GHz is designed and fabricated. The first arc-shaped slots are located in the ground conductor close to the circular transition from a feeding part to generate notch bands at 2.45, 4.9, 7.35, and 9.8GHz, while the second slot for 3.73 GHz is placed on top side in the circular patch. The proposed design method is validated by good agreement between the simulated and measured results.

Design of a Multiple Band-notched Wideband Circular Slot Antenna with Arc-shaped Slots

Junho Yeo,Cheol-Young Park 한국산업정보학회 2013 한국산업정보학회논문지 Vol.18 No.1

A design method to achieve multiple band-rejection characteristics in a wideband circular slot antenna is presented. First, a wideband circular slot antenna fed by a coplanar waveguide is designed to operate in the frequency range between 2.3 and 11GHz, which covers WLAN, WiBro, WiMAX, and UWB frequency bands. Next, resonant frequency variations of rejection bands are examined with respect to different slot locations and lengths when slots are inserted on the ground conductor and the circular patch of the antenna. When arc-shaped slots are placed close to the circular transition from a feeding part, multiple notch bands are obtained. In this case, a half of the guided wavelength of the first notch band corresponds to the slot length and other notch bands are integer-multiple of the first band. Single notch band can be obtained when the slot is located off the transition part. Based on this study, a wideband circular slot antenna with five band-rejection frequency bands at 2.45, 3.5, 4.9, 7.35, and 9.8GHz is designed and fabricated. The first arc-shaped slots are located in the ground conductor close to the circular transition from a feeding part to generate notch bands at 2.45, 4.9, 7.35, and 9.8GHz, while the second slot for 3.73 GHz is placed on top side in the circular patch. The proposed design method is validated by good agreement between the simulated and measured results.

24 GHz 대역 레이더의 평면 커버와 레이더 간의 이격 거리의 영향에 관한 연구

여준호(Junho Yeo),이종환(Jonghwan Lee),류정탁(Jeong Tak Ryu) 한국산업정보학회 2024 한국산업정보학회논문지 Vol.29 No.2

본 논문에서는 두꺼운 레이더 커버와의 이격 거리가 24 GHz 대역 레이더 성능에 미치는 영향을 실험을 통해 연구하였다. 레이더 앞에 두께 10 mm의 폴리카보네이트 레이더 커버가 놓일 때 레이더와 레이더 커버 사이의 이격 거리 변화에 따른 레이더 성능의 변화를 레이더 커버가 없을 때와 비교하였다. 레이더 성능 지표로는 레이더에서 측정된 거리를 사용하였고, 건물 내 복도에서 사람이 일정한 속도로 레이더로부터 멀리 벗어났다가 다시 가까워질 때 거리를 측정하였다. 레이더와 레이더 커버 사이의 이격 거리는 2 mm, 5 mm, 20 mm로 정하여 실험하였다. 레이더 커버가 없을 때는 49.64 m까지 거리를 측정할 수 있었고 가장 오차가 적었다. 이격 거리가 2 mm일 때는 레이더 커버의 영향으로 37.61 m부터 거리 측정이 안되는 구간이 나와서 성능이 가장 좋지 않았다. 이격 거리가 5 mm와 20 mm로 증가시켰을 때는 49.56 m까지 거리가 측정되었으나 측정된 거리와 실제 거리와의 오차가 큰 구간이 레이더 커버가 없을 때 보다 많이 발생하였다. In this paper, the effects of separation distance from a thick radar cover on the performance of 24 GHz band radar was studied through experiments. When a polycarbonate radar cover with a thickness of 10 mm was placed in front of the radar, the variations in radar performance according to the change in the separation distance between the radar and the radar cover was compared with the case without the radar cover. As a radar performance indicator, the distance measured from the radar was used, and the distance was measured using the radar when a person moves away from the radar at a constant speed in the hallway of the building and then approaches again. The separation distance between the radar and radar cover was tested at 2 mm, 5 mm, and 20 mm, respectively. When there was no radar cover, the distance could be measured up to 49.64 m and the error was the lowest. When the separation distance was 2 mm, there was a section where distance measurement was not possible starting from 37.61 m, so the performance was the worst. When the separation distance was increased to 5 mm and 20 mm, the distance was measured up to 49.56 m, but the section where the error between the measured distance and the expected distance was large occurred more often than when there was no radar cover.

V-모양 접지면을 가지는 소형 이중 대역 이중 다이폴 준-야기 안테나

여준호 ( Junho Yeo ),이종익 ( Jong-ig Lee ) 한국항행학회 2018 韓國航行學會論文誌 Vol.22 No.5

본 논문에서는 V-형 접지면을 갖고 2.45 GHz와 5 GHz 무선 랜 주파수 대역을 포함하는 이중 대역에서 동작하는 소형 이중 다이폴 준-야기 안테나의 설계 방법에 대하여 연구하였다. 먼저 2.45 GHz 대역에서 동작하는 준-야기 안테나를 설계한 후, 기존의 스트립 접지면 대신 V-모양 접지면을 사용하여 안테나의 길이를 줄여 소형화하였다. 5 GHz 대역 동작을 위해 2.45 GHz 대역 준-야기안테나의 다이폴 투사기 위에 두 번째 다이폴을 연결하고 도파기를 추가하였다. 제안된 설계 방법을 이용하여 2.45 GHz 대역과 4.57―7.11 GHz 대역에서 동작하는 이중 대역 안테나를 FR4 기판 상에 40 mm × 55 mm 크기로 제작하였다. 실험 결과, 전압정재 파비가 2 이하인 대역이 2.33―2.75 GHz과 4.38―7.15 GHz으로 원하는 이중대역에서 동작하는 것을 확인하였다. 측정된 이득은 두 대역에서 4 dBi 이상을 유지하였다. In this paper, a design method for a compact double dipole quasi-Yagi antenna with a V-shaped ground plane operating in dual bands including 2.45 GHz and 5 GHz wireless LAN frequency bands is studied. First, a quasi-Yagi antenna operating in the 2.45 GHz band is designed, and a V-shaped ground plane is used instead of a conventional strip ground plane to reduce the length of the antenna. A second dipole is connected to the dipole driver of the quasi-Yagi antenna for 2.45 GHz band and a director is appended for 5 GHz band operation. A prototype of the proposed dual-band antenna operating at 2.45 GHz WLAN band and 4.57―7.11 GHz band is fabricated on an FR4 substrate with a dimension of 40 mm by 55 mm. Fabricated antenna shows frequency bands of 2.33―2.75 GHz and 4.38―7.5 GHz for a voltage standing wave ratio less than 2. Measured gain remains more than 4 dBi in both bands.

무선 랜과 WiMAX 응용을 위한 삼중 대역 삼중 다이폴 준-야기 안테나 설계

여준호 ( Junho Yeo ),이종익 ( Jong-ig Lee ) 한국항행학회 2022 韓國航行學會論文誌 Vol.26 No.1

본 논문에서는 2.45 GHz 및 5 GHz 무선 랜 주파수 대역과 3.5 GHz WiMAX 주파수 대역에서 동작하는 삼중 다이폴 준-야기 안테나의 설계에 대하여 연구하였다. 제안된 준-야기 안테나는 V-모양 접지면과 직렬로 연결된 세 개의 다이폴로 구성된다. 길이가 가장 긴 반-보우타이 모양의 다이폴은 2.45 GHz 대역에서 공진하고, 중간 길이의 다이폴은 3.5 GHz에서 공진한다. 길이가 가장 짧은 다이폴은 5 GHz 대역에서 공진한다. 다이폴의 길이와 폭, 다이폴 사이의 간격을 조절하여 2.45 GHz, 3.5 GHz 및 5 GHz 대역에서 동작하는 삼중 대역 지향성 안테나를 설계하였고, FR4 기판 상에 45 mm × 55 mm 크기로 제작하였다. 제작된 안테나는 전압 정재파비가 2 이하인 대역이 2.32-2.57 GHz, 3.26-3.69 GHz, 4.50-6.56 GHz로 설계된 삼중 대역에서 동작하는 것을 확인하였다. 이득은 세 대역에서 3 dBi 이상을 유지하였다. In this paper, the design of a triple dipole quasi-yagi antenna operating in the 2.45 GHz and 5 GHz wireless LAN frequency bands and the 3.5 GHz WiMAX frequency band was studied. The proposed quasi-Yagi antenna consists of three dipoles connected in series with a V-shaped ground plane. The longest half-bow-tie-shaped dipole resonates in the 2.45 GHz band, whereas the medium-length dipole resonates at 3.5 GHz. The shortest dipole resonates in the 5 GHz band. By adjusting the length and width of the dipoles and the spacings between the dipoles, a triple-band directional antenna operating in the 2.45 GHz, 3.5 GHz, and 5 GHz bands are designed, and fabricated on an FR4 substrate with a size of 45 mm × 55 mm. It was confirmed that the fabricated antenna operates in the designed triple bands of 2.32-2.57 GHz, 3.26-3.69 GHz, and 4.50-6.56 GHz for a voltage standing wave ratio less than 2. Gain is maintained above 3 dBi in the three bands.