A Study on the Performance Enhancement of the Cascode FET Mixer Using New Common-Source and -Drain Configuration

The wireless communication system has become highly developed of late due to the emergence of various communication technologies, and it is becoming more widely used due to the various information requirements of its users. It has the advantages of mobility and accessibility due to easy information acquisition anytime and anywhere. Thus, the characteristics of low power consumption and high performance are required for the effective power management of the wireless communication system. It depends on a battery for system operation, however, whose efficiency and capacity for highly effective power management is still being investigated. Therefore, as the wireless communication system has limited power, it certainly requires effective RF circuits with low power consumption. The goal of this study is to develop a wireless communication system circuit with enhanced RF performance: the cascode FET mixer with new common-source and -drain circuit configuration. For the high performance of a wireless communication system with low power consumption, a well-designed RF circuit is certainly needed due to its large influence on the performance of the whole wireless communication system. If the mixer circuit is well designed, the whole wireless communication system will exhibit high performance. In this thesis, the enhanced-performance cascode FET mixer using new common-source and -drain circuit configuration is proposed. When the cascode FET mixer using new configuration was compared with the conventional one, it was found that the former has the performance of higher conversion gain at a lower input LO power, a very low noise figure, and very high LO-to-IF isolation. Thus, the proposed cascode FET mixer with enhanced RF performance can improve the performance of the wireless communication system, which can realize effective power consumption because of the use of a local oscillator with lower output power. The cascode FET mixer using new configuration was designed in this study based on the results of the simulation and measurement for the verification of the enhanced RF performance. The results showed the mixer’s enhanced RF performance compared with the conventional cascode FET mixer. The proposed new common-source and -drain circuit configuration in the cascode FET mixer is reported in this thesis for the first time. The cascode FET mixer using new configuration showed effective operation by means of the use of a local oscillator with lower output LO power. It also showed higher conversion gain with only the lower input LO power, which does not need a local oscillator with a large output power as it can be operated at lower input LO power compared with the conventional one. This is the important characteristic for the wireless communication system, which requires effective power consumption. The cascode FET mixer using new configuration showed very high LO-to-IF isolation without a LO rejection filter compared with the conventional one. It showed good LO-to-RF isolation. The cascode FET mixer using new configuration also showed a very low noise figure compared with the conventional one. It uses only a FET, which produces the effect to have very low noise figure due to the thermal and shot noise by an active device. The cascode FET mixer using new configuration showed low output IF power and low linearity for the output IF power of the fundamental and third-order intermodulation frequencies, low than those of the conventional one. It also showed the low output IF power spectrum for the intermodulation distortion of the low-side and up-side bands, as opposed to the conventional one. It showed that each reflection coefficients were about -30 dB for the RF frequency of 2.6 GHz, the LO frequency of 2.5 GHz, and the IF frequency of 100 MHz. Through the aforementioned study results, it is exhibited in this thesis that the proposed cascode FET mixer has enhanced RF performance by means of the new common-source and -drain circuit configuration. It can thus achieve high RF performance without an addition to any other circuit, for the enhancement of the RF performance. Especially, the cascode FET mixer using new configuration showed an indispensable circuit, which it must have to improve the efficiency of the wireless communication system due to the mobility and limited power.Chapter 1. Introduction 1 1.1 Background 2 1.2 Method of study 6 Chapter 2. Fundamental Concepts and Definition of Mixer 7 2.1 Definition of linearity and nonlinearity 8 2.2 Definition of frequency generation 13 2.3 Nonlinear phenomena 19 2.4 Definiton of power and gain 24 2.5 Stability 30 2.6 Mixer performance concept 32 Chapter 3. Cascode FET Mixer Design 46 3.1 Nonlinear FET devices 47 3.2 Conventional cascode FET mixer 57 3.3 Cascode FET mixer using new configuration 64 Chapter 4. Simulation and Measurement Results 76 4.1 Comparison of the simulation results 77 4.2 Comparison of the measurement results 95 Chapter 5. Conclusion 103 References 10

A Study on Highly Miniatured Active 9 ° Phase Divider and Combiner employing InGaP/GaAs HBT

Recently, the demands for miniaturized RF transceiver has been increasing in commercial mobile communication system. In this paper, we propose the active 90 ° phase divider and 90 ° phase combiner for MMIC application. Because of their very large size, conventional passive 90 ° phase divider and combiner such as branch-line coupler can't be integrated on MMIC. Therefore, highly miniaturized 90 ° phase divider and combiner are required for a development of highly integrated MMIC. The active 90 °phase divider and combiner employs the structure of common-emitter and common-collector circuit, respectively. The L, C parallel circuit was connected to emitter of HBT for phase control. And the optimal inductance and capacitance values of L, C parallel circuit was determined to obtain a phase-difference of 90 ° from the two output signals of divider. For a coupling of two signals with a phase difference of 90 ° the L, C parallel circuit was also used for combiner. In this work, we developed active 90 ° phase divider and combiner employing InGaP/GaAs HBT. According to the measured results, it was found that the active 90 ° phase divider and combiner exhibited good RF performances comparable to conventional passive divider and combiner, and they could be integrated on MMIC due to their small sizes. The size of fabricated 12GHz active 90 ° phase divider was about 32% of the conventional passive divider, and 2.4GHz active 90 ° phase combiner was about 2.2% of conventional passive combiner.제 1 장 서론 = 1 제 2 장 수동형 90 ° 위상 분배기 및 결합기 = 4 2.1 수동형 브랜치라인 커플러 90 ° 위상 분배 특성 = 4 2.2 수동형 브랜치라인 커플러 90 ° 위상 결합 특성 = 7 2.3 싱글 밸런스 믹서의 이미지 신호 제거 = 8 제 3 장 능동형 90 ° 위상 분배기 및 결합기 = 12 3.1 능동형 90 ° 위상 분배기의 구성 및 특성 = 12 3.2 능동형 90 ° 위상 결합기의 구성 및 특성 = 19 제 4 장 계산 결과 및 측정 결과 = 24 4.1 계산 결과 = 24 4.2 능동형 90 ° 위상 분배기의 측정 결과 = 43 4.3 능동형 90 ° 위상 결합기의 측정 결과 = 48 제 5 장 결론 = 53 참고문헌 = 5

유한 요소법을 이용한 평면 이방성 판재의 성형 공정 해석

Thesis (master`s)--서울대학교 대학원 :기계설계학과,1999.Maste

전자기 성형과 접착제 결합을 이용한 자동차 스페이스 프레임의 조인트 설계

Thesis(doctoral)--서울대학교 대학원 :기계항공공학부,2004.Docto

On Old English Word Order

In this paper I discussed the most important recent theories about non-configurational syntax and extended the discussion to Old English data. The viability of either a configurational or a non-configurational analysis is explored with the help of so-called indirect passive constructions. However, these constructions do not require a non-configurational analysis, since a regular, hierarchical structure can accommodate the NP arguments. The problem, then, is that in order to make a configurational proposal, we have to adopt the operation of an extra case-assignment principle-the so-called chain-government principle, which remains an ad hoc solution without apparent motivation. In this respect, I suggested the underlying assumption that old English is an SOV language with a hierarchical structure, displaying a fair amount of regularity and conformity. Verb-particle combinations and the phenomena of extraposition were suggested as strong supporting evidences for the underlying SOV hypothesis in Old English

A Study on the constructivistic development in teaching and learning mathematics

학위논문(박사)--서울大學校 大學院 :數學敎育科,1996.Docto

A Study on Low Temperature Halogenated Insulator Film Deposition byPlasma Enhanced Chemical Vapor Deposition (PECVD) and Interface Pretreatment by in situ Hydrogen Plasma

Docto

Effect of Extracellular pH on Contracture in Frog Ventricle

Potassium contractures were induced in isolated frog(Rana tcmporaria) ventricular strips with trisbuffered Ringer solutions containing 20~100mM K ions and concomitantly less Na ions at room temperaturet lS to 20nC). External pH was raised up to 8.4 or lowered down to 6.4 and its effect upon K-contracture was investigated to elicit the mechanism of action of H ions on excitation-contraction coupling in frog ventricular myocardium. Followings are the results obtained: ]. At normal pH, biphasic contracture was evoked at external K concentration of 40mM. On rasing K concentration to lOOmM, contracture tension increased gradually and the interval between the end of contracture and resuming of twitch was also prolonged. When K-20mM solution was replaced by normal Ringer solution, twitch tension developed rapidly and much higher tension than control twitch was elicited transiently. After the first application of K-100mM fully recovered tensions were always smaller than those of control twitch tensions. 2. On raising external pH from normal to 8.4, there were no significant changes in K-induced contractures comparing to those evoked under normal pH. 3. On lowering external pH down to 7.4, phasic portion of K-contractures were augmented within the range of 20 to 40mM K and tonic portions in creased gradually with time elapsed at 100mM K ion concentrations. From the above results it was concluded that H ion acted upon contracture induced by high K with low Na ion" Via the inhibition of Na-K pump during the early phase and changes in intracellular pII during the later phase