능동 위상 배열 SAR 안테나를 위한 X-대역 송수신 모듈의 설계 및 제작

정민길(Min-Kil Chong),김상근(Sang-Keun Kim),나형기(Hyung-Gi Na),이종환(Jong-Hwan Lee),이동우(Dong-Woo Yi),백승훈(Seung-Hun Baik) 한국전자파학회 2009 한국전자파학회논문지 Vol.20 No.10

본 논문에서는 능동 위상 배열 안테나를 가지는 SAR(Synthetic Aperture Radar)용 X-대역 T/R(Transmit/Receive) 모듈을 설계, 제작하였다. T/R 모듈은 X-대역에서 800 ㎒ 이상 대역폭을 가지며 이중 편파 운용이 가능하다. 송신 출력 7 W 이상에 잡음지수 3.9 ㏈ 이하를 가진다. 위상과 이득은 6비트 위상변위기와 6비트 디지털 감쇠기에 의해 각각 제어된다. 게다가 제작된 T/R 모듈은 방향성 결합기와 전력분배기로 연결되는 성능 점검/보정 포트를 가진다. LTCC 다층 기판을 사용하여 고직접화 T/R 모듈이 가능하게 하였다. 모든 동작 주파수 대역에서 수신시 RMS 이득 오차는 최대 0.8 ㏈ 이하이고, 송/수신시 RMS 위상 오차는 최대 4° 이하로 측정되었고, 또한 시험 결과 T/R 모듈은 요구되는 전기적인 성능을 만족하였다. 이 구조는 능동 위상 배열 SAR용 안테나에 적용될 수 있음을 확인하였다. In this paper, a X-Band T/R-module for SAR(Synthetic Aperture Radar) systems based on active phased array antennas is designed and fabricated. The T/R modules have a bandwidth of more than 800 ㎒ centered at X-Band and support dual, switched polarizations. The output power of the module is 7 watts over a wide bandwidth. The noise figure is as low as 3.9 ㏈. Phase and amplitude are controlled by a 6-bit phase shifter and a 6-bit digital attenuator, respectively. Further the fabricated T/R module has test and calibration port with directional coupler and power divider. Highly integrated T/R module is achieved by using LTCC(Low Temperature Co-fired Ceramic) multiple layer substrate. RMS gain error is less than 0.8 ㏈ max. in Rx mode, and RMS phase error is less than 4° max. in Rx/Tx phase under all operating frequency band, or the T/R module meet the required electrical performance in test. This structure can be applied to active phase array SAR Antennas.

광대역 위상 배열 안테나의 빔 편이(Beam-Squint) 현상 제거를 위한 4-Bit 시간 지연기 설계

김상근(Sang-Keun Kim),정민길(Min-Kil Chong),김수범(Su-Bum Kim),나형기(Hyung-Gi Na),김세영(Se-Young Kim),성진봉(Jin-Bong Sung),백승훈(Seung-Hun Baik) 한국전자파학회 2009 한국전자파학회논문지 Vol.20 No.10

본 논문에서는 전기적으로 크기가 큰 능동 위상 배열 안테나에서 발생하는 빔-편이(beam-squint) 현상을 해결할 수 있는 시간 지연기를 설계 및 제작하고, 측정 결과를 고찰한다. 시간 지연기는 4-bit 스위치로 제어되는 마이크로스트립 라인으로 설계되었으며, 시간 지연 구조의 손실을 보상해 주기 위해 송수신 경로에 MMIC 증폭기 모듈을 추가하였다. 시간 지연기의 측정을 통해 지연 상태별 이득 및 위상, P1㏈, 수신 잡음 지수 등의 전기적 성능 규격을 만족함을 확인하였다. 또한, 제작된 시간 지연기의 성능 검증을 위해 측정 결과를 광대역 능동위상 배열 안테나에 적용하여 빔 패턴 보정 효과를 확인하였다. X 밴드 대역에서 800 ㎒ 대역차를 갖는 675.8 ㎜ 크기의 안테나에 대해 빔 편이 현상을 보정해 본 결과 ±1°이던 주파수에 따른 조향각 오차가 ±0.1° 이내로 줄어드는 효과를 확인하였으며, 향후 광대역 능동 위상 배열 안테나 시스템에 적용 가능성을 확인하였다. In this paper, we have designed TDL(True-time Delay Line) for eliminating beam-squint occurring in active phased array antenna with large electrical size operated in wide bandwidth, and have tested its electrical performance. The proposed TDL device is composed of 4-bit microstrip delay line structure and MMIC amplifier for compensation of the delay-line loss. The measured results of gain and phase versus delay state satisfy the electrical requirements, also P1dB output power and noise figure meet the requirement. To verify the performance of fabricated TDL, we have simulated the beam patterns of wide-band active phased array antenna using the measured results and have certified the beam pattern compensation performance. As a result of simulated beam pattern compensation with respect to the 675.8 ㎜ size antenna which is operated in X-band, 800 ㎒ bandwidth, we have reduced the beam squint error of ±1° with ±0.1°. So this TDL module is able to be applied to active phase array antenna system.

능동 위상 배열 레이더용 X-대역 T/R 모듈 개발

김동윤(Dong-Yoon Kim),정민길(Min-Kil Chong),김상근(Sang-Keun Kim),전상미(Sang-Mi Chon),나형기(Hyung-Gi Na),백승훈(Seung-Hun Baik),안창수(Chang-Soo Ahn),김선주(Seon-Joo Kim) 한국전자파학회 2009 한국전자파학회논문지 Vol.20 No.12

본 논문에서는 능동 위상 배열 레이더에 사용되는 X-밴드 송수신 모듈의 설계와 측정 결과에 대해 기술한다. 일반적으로 능동 위상 배열 레이더는 고출력, 낮은 잡음 지수, 높은 TOI(Third Order Intercept), 송수신에서의 충분한 이득을 갖는 반도체 송수신 모듈을 요구한다. 송수신 모듈은 광대역에서 9 W의 출력 특성을 나타낸다. 잡음 지수는 2.8 ㏈로 낮다. 위상과 이득은 각각 6비트 위상 변위기와 5비트 감쇄기로 조정된다. LTCC(Low Temperature Co-fired Ceramic)을 사용하여 높은 집적도를 갖는 송수신 모듈을 구현하였다. 모듈은 디지털 인터페이스를 통합하고 3개의 전원을 사용한다. This paper presents design and test results of X-Band Transmit/Receive(T/R) module for active phased-array radar. Active phased array radars typically require solid state T/R modules with high output power, low noise figure, high Third Order Intercept(TOI), and sufficient gain in both transmit and receive. The output power of the module is 9 watts over a wide bandwidth. The noise figure is as low as 2.8 ㏈. Phase and amplitude are controlled by the 6-bit phase shifter and 5-bit attenuator, respectively. Highly integrated T/R module is achieved by using LTCC(Low Temperature Co-fired Ceramic) multiple layer substrate. The module incorporates a compact digital interface, requires only three supply voltages.

Vecuronium 투여방법에 따른 근이완 발현시간에 대한 고찰

백승훈,백승완,신상욱,김해규,정규섭,김인세 대한마취과학회 1998 Korean Journal of Anesthesiology Vol.35 No.1

Background : Priming significantly shortened the onset of neuromuscular blockade(NMB), but also results in a high incidence of side effects. This study was designed to determine the effect of infusion priming method on the side effects, intubation condition, and onset of NMB compared with divided priming method. Method : The effects of different priming method of vecuronium on onset time and endotracheal intubation condition were investigated. 40 patients were studied in two parts. In control part, 20 patients were allocated into two groups(n=10 in each group) receving 10, 20 g/kg vecuronium as a priming dose, followed by a intubating dose(0.1 mg/kg-priming dose) 3 min later; the other part, 20 patients were allocated into two groups(n=10 in each group) receving 0.2 mg/kg/hr vecuronium continuous intravenous infusion, followed by a intubating dose(0.1 mg/kg-total infusion dose) 3, 5 min later. Onset time is calculated by single twitch stimulation test from injection of the intubating dose to maximum depression of the single twitch. Intubatin condition was appreciated based on vocal cord reflex, coughing, and jaw relaxation and scored. Results : The times to fade out on the single twitch of the intravenous infusion priming group were shorter than control priming group. There was no difference between control priming group and infusion priming group to evaluate the intubation conditions. Side effects in the continuous infusion group were lesser than control priming group. Conclusion : This results suggest that the use of continuous infusion method is one of the promising methods to shorten the neuromuscular blockade and to provide more comfort to the patients. (Korean J Anesthesiol 1998; 35: 76∼81)

소아의 자가조절진통에서 Morphine과 Fentanyl의 비교

백승완,김해규,김경훈,백승훈,김운성 부산대학교 병원 암연구소 2007 부산대병원학술지 Vol.- No.21

Purpose: Patient controlled analgesia (PCA) of opioids is a effective analgesic technique for children. But postoperative complications prevent children fully benefiting from their peA. We have compared morphine based PCA with fentauyl based PCA during pediatric orthopedic surgery. Subject and Methods: Sixty children (5-14 years old) after orthopedic surgeries allocated into two group. Morphine group received morphine based PCA; loading dose 0.1 ㎎/㎏, continuous infusion 0.05 ㎎/㎏/hr, bolous dose 0.025 ㎎/㎏. Fentanyl group received fentanyl based PCA; loading dose 1 ㎍/㎏, continuous infusion 0.5 ㎎/㎏/hr, bolus dose 0.25 ㎍/㎏. Pain was assessed by visual analogue scale (VAS). Scores for pain, respiratory depression, sedation, prutitus, nausea, vomiting and bolus counts and PCA dose were recorded at recovery room, 12 hour, 24 hours and 48hours after surgery. Results: There were no differences in VAS score between two groups on each times. The incidences of respiratory depression, sedation, pruritus, nausea and vomiting were no differences, too. But cumulative bolus demands was significantly higher in fentanyl group on 24 hours and 48 hours after surgery (P < 0.05). Conclusions: Morphine based PCA was similar effect with fentanyl based PCA, in controlling postoperative pain. Furthermore, morphine based PCA offer cost-effectiveness over fentanyl based PCA and do not increase the incidence of side effects.