• 대한전자공학회논문지SD
• /
• 제47권3호
• /
• pp.51-57
• /
• 2010

IEEE 802.11n 기반 무선 LAN과 IEEE 802.16e 기반 Mobile WiMAX에 적용할 수 있는 이중모드 직접 변환 수신기를 $0.13\;{\mu}m$ RF CMOS 공정을 이용하여 설계하였다. 설계된 직접 변환 수신기는 2.3-2.7 GHz의 주파수 범위에서 동작을 한다. 저잡음 증폭기에 Current Steering 기술을 사용하여 전체 이득의 크기를 3 단계로 조절이 가능하게 하였다. 플리커 잡음 영향을 낮추기 위해 믹서에 Current Bleeding 기술을 사용하였다. 믹서 LO를 위한 I/Q 위상 신호 발생을 위해 주파수 2-분주회로를 포함하였다. 제작된 직접 변환 수신기는 1.4V의 공급 전원에서 LO 버퍼를 포함하여 56 mA를 사용하며, 32 dB의 전력이득과 4.8dB의 잡음지수, 그리고 +6 dBm의 출력 $P_{1dB}$를 가진다.

• Journal of electromagnetic engineering and science
• /
• 제17권4호
• /
• pp.178-180
• /
• 2017

This study presents a 2-20 GHz monolithic distributed power amplifier (DPA) using a $0.25{\mu}m$ AlGaN/GaN on SiC high electron mobility transistor (HEMT) technology. The gate width of the HEMT was selected after considering the input capacitance of the unit cell that guarantees decade bandwidth. To achieve high output power using small transistors, a 12-stage DPA was designed with a non-uniform drain line impedance to provide optimal output power matching. The maximum operating frequency of the proposed DPA is above 20 GHz, which is higher than those of other DPAs manufactured with the same gate-length process. The measured output power and power-added efficiency of the DPA monolithic microwave integrated circuit (MMIC) are 35.3-38.6 dBm and 11.4%-31%, respectively, for 2-20 GHz.

• 한국잠사학회:학술대회논문집
• /
• 한국잠사학회 2002년도 Join Meetings of Korean Society of Sericultural Science and Japanse Society of Sericultural Science
• /
• pp.65-65
• /
• 2002

No Abstract, See Full Text

• Asian Pacific Journal of Cancer Prevention
• /
• 제14권6호
• /
• pp.3711-3717
• /
• 2013

Background: To assess the efficacy and tolerability of Cisplatin plus Gemcitabine combination in patients with brain metastases (BM) from breast cancer (BC). Materials and Methods: Eighteen BC patients with BM who were treated with Cisplatin plus Gemcitabine regimen between 2003-2011 were evaluated. Results: A median of 6 cycles of this regimen were received, in fifteen patients (83.3%) as first-line chemotherapy, in 2 as second-line and in 1 as third-line after diagnosis of BM. Dose reduction was performed in 11 (61.1%) patients; major reasons were neutropenia and leukopenia. Grade III neutropenia and Grade II trombocytopenia rates were 33.3% and 16.7% respectively. Overall response rate (ORR; complete+partial response rate) was 33.4% (n=6) for the entire study population; triple negative patients achieved an 66.6% ORR while hormone receptor (HR) positive patients had 25% and HER2 positive patients 12.5%. Median progression-free survival was 5.6 months (2.4-8.8 months, 95%CI) and longer in patients with triple negative breast cancer (TNBC) (median 7.4 months, 95%CI, 2.4-12.3 months) than the patients with other subtypes (median 5 months for HER2 positive and 3.6 months for HR positive patients). Median PFS of the patients with TNBC who received this regimen as first-line was 9.2 months (5.2-13.2 months, 95%CI). Conclusions: Cisplatin plus Gemcitabine may be a treatment option for patients with BM from breast cancer. Longer PFS and higher response rates are results that support the usage of this regimen especially for the triple negative subtype. However, further prospective and randomized trials are clearly required to provide more exact information.

• Journal of electromagnetic engineering and science
• /
• 제15권2호
• /
• pp.82-88
• /
• 2015

The magnetron, a vacuum tube, is currently the usual high-power microwave power source used for microwave heating. However, the oscillating frequency and output power are unstable and noisy due to the low quality of the high-voltage power supply and low Q of the oscillation circuit. A heating system with enhanced reliability and the capability for control of chemical reactions is desired, because microwave absorption efficiency differs greatly depending on the object being heated. Recent studies on microwave high-efficiency power amplifiers have used harmonic processing techniques, such as class-F and inverse class-F. The present study describes a high-efficiency 100 W GaN-HEMT amplifier that uses a harmonic processing technique that shapes the current and voltage waveforms to improve efficiency. The fabricated GaN power amplifier obtained an output power of 50.4 dBm, a drain efficiency of 72.9%, and a power added efficiency (PAE) of 64.0% at 2.45 GHz for continuous wave operation. A prototype microwave heating system was also developed using this GaN power amplifier. Microwaves totaling 400 W are fed from patch antennas mounted on the top and bottom of the microwave chamber. Preliminary heating experiments with this system have just been initiated.

• JSTS:Journal of Semiconductor Technology and Science
• /
• 제11권4호
• /
• pp.309-317
• /
• 2011

This paper describes a baseband analog (BBA) chain for wireless local area network (WLAN) applications. For the given specifications of the receiver BBA chain, the optimum allocation of the gain and filter rejection of each block in a BBA chain is achieved to maximize the SFDR. The fully integrated BBA chain is fabricated in 0.13 ${\mu}m$ CMOS technology. An input-referred third-order intercept point (IIP3) of 22.9 dBm at a gain of 0.5 dB and an input-referred noise voltage (IRN) of 32.2 nV/${\surd}$Hz at a gain of 63.3 dB are obtained. By optimizing the allocation of the gain and filter rejection using the proposed design methodology, an excellent SFDR performance of 63.9 dB is achieved with a power consumption of 12 mW.

• 한국전자파학회논문지
• /
• 제20권7호
• /
• pp.657-663
• /
• 2009

본 논문에서는 IR-UWB 통신에 적합한 저전력, 저복잡도의 CMOS RF 수신기를 제작하였다. 제안된 IR-UWB 수신기는 비교적 구조가 간단한 non-coherent demodulation 방식으로 설계, 제작되었다. 설계된 IR-UWB 수신기는 single-ended 2-stage LNA, S2D, envelop detector, VGA, comparator로 구성되어 있으며, 0.18 ${\mu}m$ CMOS 공정 기술을 이용하여 단일 칩으로 설계, 제작하였다. 측정 결과 data rate이 1 Mbps 일 때 BER값이 $10^{-3}$ 조건에서 sensitivity는 -80.8 dBm이다. 제작된 단일 칩 CMOS IR-UWB 수신기의 전류 소모는 전압이 1.8 V 일 때, 13 mA이며 23.4 nJ/bit 의 성능을 갖는다.

• 한국산학기술학회논문지
• /
• 제16권12호
• /
• pp.8643-8648
• /
• 2015

본 논문은 Ka대역 위성통신 탑재체의 하향링크대역인 주파수 19.5 GHz ~ 22 GHz대역에서 사용가능한 8W급 전력증폭기를 3단으로 설계 및 제작하여 특성 평가한 과정을 기술하였다. 제작된 전력증폭기 GaN MMIC는 3단으로 구성된 HEMT(High Electron Mobility Transistor)들로 이루어 졌으며 증폭기의 첫 번째단 게이트 폭은 $8{\times}50{\times}2um$, 두 번째단 게이트폭은 $8{\times}50{\times}4um$, 마지막단인 출력단의 게이트 폭은 $8{\times}50{\times}8um$의 구조로 이루어 졌다. 0.15 um GaN 공정으로 제작된 전력 증폭기 MMIC의 사이즈는 $3,400{\times}3,200um^2$ 이고 주파수 19.5 GHz ~ 22 GHz대역에서 입력 전압 20 V 일 때, 소신호 및 대신호 측정 결과 소신호 이득 29.6 dB 이상, 입력정합 최소 -8.2 dB, 출력정합 -9.7 dB, 최소 39.1 dBm의 출력전력, 최소 25.3%의 전력 부가 효율을 나타내었다. 따라서 설계 및 제작된 전력증폭기 MMIC는 Ka대역 위성통신 탑재체의 하향링크에 사용이 가능할 것으로 판단된다.

• 한국전자파학회논문지
• /
• 제10권1호
• /
• pp.70-77
• /
• 1999

세라믹 적층기술을 이용하여 PCS 주파수 대역의 초소형 vco를 설계하고 제작하였다. 위상잡음 특성을 개선하고 크기를 줄이기 위하여 품칠계수(quality factor)가 우수한 세라믹 다층기판으로 스트립라인을 구현 하여 vco 공진부의 인덕터로 사용하였다 1.720 -1.780 MHz에서 동작하도록 제작된 vco는 $6mm\times6mm\times2mm$의 크기로 초소형이며, 3.3 V, 9 mA의 바이어스 조건에서 - 3.7 dBm의 출력을 얻었고, 위상잡음 특성 은 10 KHz offset에서 95 dBe/Hz였다 본 논문에서 제작된 세라믹 VCo는 기존의 에폭시 수지(FR4) 기판을 사용한 VCo보다 약 5 dBe/Hz 개선된 위상잡음(C/N) 특성을 얻었다.

• Journal of electromagnetic engineering and science
• /
• 제14권4호
• /
• pp.399-404
• /
• 2014

A power amplifier (PA) for a femto-cell base station should be highly efficient, linear and small. The efficiency for amplification of a high peak-to-average power ratio (PAPR) signal was improved by designing an asymmetric Doherty PA (DPA). The linearity was improved by applying third-order inter-modulation (IM3) cancellation method. A small size is achieved by designing the DPA using GaN MMIC process. The implemented 2-stage DPA delivers a power-added efficiency (PAE) of 38.6% and a gain of 33.4 dB with an average power of 34.2 dBm for a 7.2 dB PAPR 10 MHz bandwidth LTE signal at 2.14 GHz.