Integrated Bias Circuits of RF CMOS Cascode Power Amplifier for Linearity Enhancement

Bonhoon Koo,Yoosam Na,Songcheol Hong IEEE 2012 IEEE transactions on microwave theory and techniqu Vol.60 No.2

<P>This paper presents a highly linear differential cascode CMOS power amplifier (PA) with gate bias circuits in Common Source (CS) and Common Gate (CG) amplifiers. The proposed Class-D bias circuit at the gate of a CS amplifier injects a reshaped envelope signal only when the envelope signal is above a certain threshold voltage. This improves the linearity of the PA without significantly degrading the efficiency in a high-power region. In addition, the proposed bias circuit at the gate of a CG amplifier controls the second-order nonlinear components to improve the linearity and to reduce the sideband (IMD or ACLR) asymmetry, simultaneously. A single-stage PA including the bias circuits was fabricated using a 0.18-μ m CMOS process, with an integrated passive device (IPD) transmission line transformer (TLT). With a 3.5 V supply, the measurements show that 26.8 dBm with 43.3% PAE at -37 dBc ACLR (5 MHz offset) and 27.8 dBm with 45.8% PAE at -33 dBc ACLR (5 MHz offset) at 1.85 GHz under 3GPP WCDMA test without digital pre-distortions.</P>

한국인들은 어떤 민주주의를 왜 선호하는가?: 엘리트민주주의 대 참여민주주의

구본훈 ( Bonhoon Koo ),민정훈 ( Jeonghoon Min ),조영호 ( Youngho Cho ) 경남대학교 극동문제연구소 2020 한국과 국제정치 Vol.36 No.4

그 동안 학계에서 한국인들이 어떤 민주주의를 선호하는지에 대한 연구는 부족하였다. 한국 유권자들이 지지하는 민주주의 유형에 대한 선행연구들도 활용된 자료와 질문에 따라 결과가 차이를 보여 왔다. 이에 본 연구는 전국적 대표성을 가진 대면면접 자료를 활용하여 한국인들의 민주적 의사결정방식에 대한 태도를 조사하였다. 분석 결과, 한국인들이 참여 민주주의를 가장 선호한다는 점을 발견하였으나, 그 양상은 선행연구들과 다소 달랐다. 나아가 참여 민주주의 지지에 대한 요인을 분석한 결과, 응답자들의 정치불만과 정파성이 유의미한 상관관계를 가졌다. 마지막으로 서구와 달리 정치관심과 교육수준이 높은 관심시민들(attentive citizens)이 참여민주주의를 선호한다는 근거를 발견하지 못하였지만, 정치불만이 높은 조건에서 이들의 선호가 참여적으로 변화한다는 상호작용 효과를 확인할 수 있었고, 이는 한국인들의 정치참여에 관한 중요한 시사점을 제공한다. Prior studies are limited in examining what democracy Koreans prefer. Among those studies, there are differences that result from differing survey data and questions. Employing a face-to-face survey with national representation, this study examines Korean citizens’ attitudes toward the decision-making process of democratic government. The analytical results reveal that participatory democracy is strongly preferred by Korean citizens, but the details are somewhat different from those of the prior studies. Moreover, we show that political dissatisfaction and partisanship are associated with citizens’ support for participatory democracy. Finally, we do not find that attentive citizens with political interest and educational attainment support participatory democracy, but we determine that their preference moves to participatory democracy in the condition of high political dissatisfaction. This interactive effect offers an important implication about the political participation of Korean citizens.

Two Cases of Hypersexuality Probably Associated with Aripiprazole

EunJin Cheon,BonHoon Koo,SangSoo Seo,JunYeob Lee 대한신경정신의학회 2013 PSYCHIATRY INVESTIGATION Vol.10 No.2

Sexual dysfunction is a common side effect in patients treated with antipsychotics but significant differences exist across different compounds. We report hypersexuality symptoms in two female patients with schizophrenia who were receiving treatment with aripiprazole. The patients experienced more frequent sexual desire and greater sexual preoccupation after taking aripiprazole. We discuss the potential neuro-chemical mechanisms for this and argue that aripiprazole’s unique pharmacological profile, partial agonism with high affinity at dopamine D2-receptor, may have contributed to the development of these symptoms.

A WLAN RF CMOS PA With Large-Signal MGTR Method

Taehwan Joo,Bonhoon Koo,Songcheol Hong IEEE 2013 IEEE transactions on microwave theory and techniqu Vol.61 No.3

<P>A CMOS linear power amplifier for wireless local area network IEEE 802.11b/g application is presented. To achieve high linear output power and high efficiency, a large-signal multigated transistor linearization method is proposed with an envelope injection gate bias circuit. A novel inter-stage matching transformer, which functions as a power splitter, is designed to implement this method. It is fabricated with a TSMC 0.13-μm standard RF CMOS process. Measurement shows 19.5-dBm <I>P</I>out with 24.8% power-added efficiency (PAE) at - 25-dB error vector magnitude with an orthogonal frequency-division multiplexing 64-QAM 54-Mb/s 802.11g signal source and 23.15-dBm <I>P</I>out with 31.73% PAE with DSSS, CCK, and 11-Mb/s 802.11b signal source without digital pre-distortion.</P>

RF CMOS Power Amplifiers for Mobile Terminals

Ki Yong Son,Bonhoon Koo,Yumi Lee,Hongtak Lee,Songcheol Hong 대한전자공학회 2009 Journal of semiconductor technology and science Vol.9 No.4

Recent progress in development of CMOS power amplifiers for mobile terminals is reviewed, focusing first on switching mode power amplifiers, which are used for transmitters with constant envelope modulation and polar transmitters. Then, various transmission line transformers are evaluated. Finally, linear power amplifiers, and linearization techniques, are discussed. Although CMOS devices are less linear than other devices, additional functions can be easily integrated with CMOS power amplifiers in the same IC. Therefore, CMOS power amplifiers are expected to have potential applications after various linearity and efficiency enhancement techniques are used.

Stress and Heart Rate Variability: A Meta-Analysis and Review of the Literature

HyeGeum Kim,EunJin Cheon,DaiSeg Bai,YoungHwan Lee,BonHoon Koo 대한신경정신의학회 2018 PSYCHIATRY INVESTIGATION Vol.15 No.3

Objective-Physical or mental imbalance caused by harmful stimuli can induce stress to maintain homeostasis. During chronic stress, the sympathetic nervous system is hyperactivated, causing physical, psychological, and behavioral abnormalities. At present, there is no accepted standard for stress evaluation. This review aimed to survey studies providing a rationale for selecting heart rate variability (HRV) as a psychological stress indicator. Methods-Term searches in the Web of Science??, National Library of Medicine (PubMed), and Google Scholar databases yielded 37 publications meeting our criteria. The inclusion criteria were involvement of human participants, HRV as an objective psychological stress measure, and measured HRV reactivity. Results-In most studies, HRV variables changed in response to stress induced by various methods. The most frequently reported factor associated with variation in HRV variables was low parasympathetic activity, which is characterized by a decrease in the high-frequency band and an increase in the low-frequency band. Neuroimaging studies suggested that HRV may be linked to cortical regions (e.g., the ventromedial prefrontal cortex) that are involved in stressful situation appraisal. Conclusion-In conclusion, the current neurobiological evidence suggests that HRV is impacted by stress and supports its use for the objective assessment of psychological health and stress.

노인 우울증 환자에서 Aripiprazole과 Bupropion 부가요법의 효과 및 안전성 비교 : 사후분석연구

조소혜(Sohye Jo),천은진(Eunjin Cheon),이광헌(Kwanghun Lee),구본훈(Bonhoon Koo),박영우(Youngwoo Park),이종훈(Jonghun Lee),이승재(Seungjae Lee),성형모(Hyungmo Sung) 대한생물치료정신의학회 2019 생물치료정신의학 Vol.25 No.2

Objectives:The purpose of this study was to compare aripiprazole versus bupropion augmentation therapy in older adult patients with major depressive disorder unresponsive to selective serotonin reuptake inhibitors(SSRIs). Methods:This is a post-hoc analysis of a 6-week, randomized prospective open-label multi-center study in thirty older adult patients with major depressive disorder. Participants were randomized to receive aripiprazole(N=16, 2.5-10mg/day) or bupropion(N=14, 150-300mg/day) for 6 weeks. Montgomery Asberg Depression Rating Scale (MADRS), 17-item Hamilton Depression Rating scale(HAM-D17), Iowa Fatigue Scale, Drug-Induced Extrapyramidal Symptoms Scale, Psychotropic-Related Sexual Dysfunction Questionnaire scores, and Clinical Global Impression-Severity (CGI-S) were obtained at baseline and after one, two, four, and six weeks. Changes on individual items of HAM-D17 were assessed as well as on composite scales(anxiety, insomnia and drive), and on four core subscales that capture core depression symptoms. Results:There was a significantly greater decrease in MADRS scores in aripiprazole group compared to bupropion group at 4(p<0.05) and 6(p<0.05) weeks. There were significantly higher response rate at week 4(p<0.05) and 6(p<0.05) and remission rate at week 6 in aripiprazole group compared to bupropion group. Individual HAM-D17 items showing significantly greater change with adjunctive aripiprazole than bupropion: insomnia, late(ES=0.81 vs. -0.24, p=0.043), psychomotor retardation(ES=1.30 vs. 0.66, p=0.024), general somatic symptoms(ES=1.24 vs. 0.00, p=0.01). On three composite scales, adjunctive aripiprazole was significantly more effective than bupropion with respect to mean change for drive(p=0.005). Conclusion:Results of this study suggested that aripiprazole augmentation have superior efficacy in treating general and core symptoms of depression in older adult patients. Aripiprazole augmentation is associated with greater improvement in specific symptoms of depression such as psychomotor retardation, general somatic symptoms and drive.