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후면 그라운드를 이용한 휴대단말 Wi-Fi 칩 안테나 설계
오세원(Saewon Oh),김형동(Hyeongdong Kim) 한국전자파학회 2012 한국전자파학회논문지 Vol.23 No.5
본 논문에서는 휴대단말기의 Wi-Fi 대역에서 동작하는 소형 칩 안테나를 설계하였다. 제안된 안테나의 소형화를 위해 칩 안테나 하단에 후면 그라운드를 갖도록 설계하였다. 제안된 안테나는 S자 모양 대칭형으로 유전율이 3.5인 LCP(Liquid Crystal Polymer) 위에 설계되었으며, 칩 안테나의 전체 크기는 6.0 mm×2.5 mm×1.2 mm를 갖는다. 제작된 안테나는 VSWR=3 이하 기준 300 MHz(fractional bandwidth: 12.2 %, 2.3~2.6 GHz)의 임피던스 대역폭과 peak gain은 1.42 dBi의 특성을 나타냈다. 안테나 설계는 CST Microwave Studio 상용 프로그램을 사용하여 최적화한 후, 설계된 안테나를 제작하고, 네트워크 분석기와 무반향실을 이용하여 측정하였다. In this paper, a new small chip antenna for Wi-Fi application of the mobile handset is proposed. To miniaturize the chip antenna, the proposed antenna is designed to have the backside ground. The proposed antenna has S-shaped structure, which is designed on the LCP(Liquid Crystal Polymer) with εr =3.5. The size of the proposed antenna is 6.0 mm×2.5 mm×1.2 mm. The measured impedance bandwidth under a voltage standing wave ratio (VSWR) of 2 was 300 MHz(fractional bandwidth: 12.2 % 2.3~2.6 GHz), and peak gain is 1.42 dBi. The proposed antenna was designed using CST Microwave Studio commercial software tool. And the fabricated antenna is measured using a network analyzer and in anechoic chamber.
차실내 이산화탄소 농도 제어를 통한 A/C부하 감소 및 연비 향상
이정훈(Jeonghoon Lee),김영민(Youngmin Kim),오세원(Saewon Oh),박준규(Jungyu Park),김영길(Yeongkil Kim),김무용(Muyong Kim),구준모(Junmo Ku) 한국자동차공학회 2011 한국자동차공학회 학술대회 및 전시회 Vol.2011 No.11
Automotive air conditioning decreases approximately 25% of the vehicle fuel economy in the case of the summer and about 10% per year. A recirculation air mode, in which outside hot air influx is blocked, can improve fuel economy because a ventilation loss covers more than 10% of thermal heat load, but long time stay in this mode cause discomfort in ventilation. According to the United States air quality-related standards, CO₂ concentration, 2000 ppm and later, may induce drowsiness and can lead to the possibility of a vehicle crash, so the CO₂ concentration control is important. In this study, NDIR-Non Dispersive Infrared- CO₂ sensor measured the cabin concentrations in real time, a recirculation air rate and airflow to the cabin improved fuel economy and comfort in ventilation. This algorithm came from response surface method through a lot of vehicle experiments and computer simulation results, In ambient temperature 35℃, humidity 40%RH, vehicle speed 80 ㎞/h, sunload 850W/m2, 2 persons boarding conditions, through cabin CO₂ concentration remained constant or below 1000ppm, fuel economy increased approximately 4.5%. Also, this paper proposed the integrated recirculating air control strategies to block exhaust gas inflow into cabin by AQS (Air Quality Sensor) system and prevent fogging on windshield glass using ADS(Auto Defog Sensor) system.