• 전자통신동향분석
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• 제37권5호
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• pp.11-21
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• 2022

GaN (Gallium-Nitride) is a promising candidate material in various radio frequency applications due to its inherent properties including wide bandgap, high carrier concentration, and high electron mobility/saturation velocity. Notably, AlGaN/GaN heterostructure field effect transistor exhibits high operating voltage and high power-density/power at high frequency. In next-generation radar systems, GaN power transistors and monolithic microwave integrated circuits (MMICs) are significant components of transmitting and receiving modules. In this paper, we introduce technological trends for C-/X-/Ku-band GaN MMICs including power amplifiers, low noise amplifiers and switch MMICs, focusing on the status of GaN MMIC fabrication technology and GaN foundry service. Additionally, we review the research for the localization of C-/X-/Ku-band GaN MMICs using in-house GaN transistor and MMIC fabrication technology. We also discuss the results of C-/X-/Ku-band GaN MMICs developed at Defense Materials and Components Convergence Research Department in ETRI.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2009년도 제40회 하계학술대회
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• pp.1939_1941
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• 2009

The modulation quality of the RF transmitter in a wireless communication system usually affects system performance and it mostly depends on both a nonlinearity and a distortion, from the intermodulation products and the I/Q mismatch such as I/Q amplitude error and a local phase error, respectively. This paper focused on how much the error vector magnitude(EVM) which describes the modulation accuracy changes according to the variation of the I/Q mismatch components at I/Q modulator. For this work, the equation for the EVM including the I/Q mismatch components can be induced and calculated in accordance with the variation of the I/Q mismatch components. Consequently, the effect of I/Q mismatch components on the EVM, which is required in the transmitter specification of Personal Area Network, can be clearly analyzed.

• Transactions on Electrical and Electronic Materials
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• 제16권3호
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• pp.142-145
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• 2015

In this work, open stubs were fabricated on a polyether sulfone (PES) substrate, and their basic radio frequency (RF) characteristics were investigated for application to RF matching components of a flexible monolithic microwave integrated circuit (MMIC). According to the results, an open stub employing coplanar waveguide (OSCPW) on PES exhibited much lower loss than that on silicon substrate. The OSCPW with a length of $500{\mu}m$ on PES showed capacitance values of 0.031 ~ 0.044 pF from 0.5 to 50 GHz. For application to a relatively high-value capacitive matching, an open stub employing a fishbone-type transmission line (OSFTTL) was fabricated on PES, and its characteristics were investigated. The OSFTTL showed much higher capacitance values than the OSCPW due to the high effective permittivity value. Specifically, the OSFTTL on PES showed capacitance values of 0.066 ~ 0.24 pF from 0.5 to 50 GHz, which are higher than those for the open stub on silicon substrate. The above results indicate that the OSCPW and OSFTTL on PES can be effectively used for application to low/high-value capacitive matching components on microwave and millimeter wave flexible MMIC. To the best of the authors' knowledge, this work is the first report of the investigation of RF capacitive matching components on PES substrate.

• 산업기술연구
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• 제29권B호
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• pp.145-149
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• 2009

A RF-DC converter is one of the most important components for a wireless power transmission. It has been developed for many applications such as space solar power system, and Radio Frequency Identification(RFID). In this paper, we designed three types of RF-DC converter and compare the performance of each. All types RF-DC convertoer have a maximum conversion efficiency at input power level of 0 dBm~5 dBm and RF-DC converter of third type was the best performance that has a 21.9% of conversion efficiency.

• 제어로봇시스템학회논문지
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• 제10권6호
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• pp.566-573
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• 2004

This paper describes the ubiquitous home network (uHome-net) testbed and LonRF intelligent devices based on LonWorks technology. These devices consist of Neuron Chip, RF transceiver, sensor, and other peripheral components. Using LonRF devices, a home control network can be simplified and most devices can be operated on LonWorks control network. Also, Indoor Positioning System (IPS) that can serve various location based services was implemented in uHome-net. Smart Badge of IPS, that is a special LonRF device, can measure the 3D location of objects in the indoor environment. In the uHome-net testbed, remote control service, cooking help service, wireless remote metering service, baby monitoring service and security ＆ fire prevention service were realized. This research shows the vision of the ubiquitous home network that will be emerged in the near future.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2004년도 하계학술대회 논문집 Vol.5 No.2
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• pp.652-655
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• 2004

RF MEMS is a miniature device or an array of integration devices and mechanical components and fabricated with If batch-processing techniques. RF MEMS application area are in phased arrays and reconfigurable apertures for defence and telecommunication systems, switching network for satellite communication, and single-pole double throw switches for wireless application. Recently, RF MEMS switches have been developed for the application to the milimeter wave system. RF MEMS switches offer a substantilly higher performance than PM diode or FET switches. In this paper, SPDT(single-pole-double-throw) switch are designed to use 10 GHz. Actuation voltage and displacement are simulated by tool. And stress and distribution are simulated.

• 마이크로전자및패키징학회지
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• 제9권2호
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• pp.45-48
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• 2002

LTCC 시스템은 가격이 저렴하고 공정이 안정적이고 전기적 특성에서도 손실값이 작은점등의 많은 장점을 가지고 있다. 그러나 일단 제작된 소자들에 대해서는 튜닝 작업이 어려운 단점이 있다. 이때문에 수 GHz이상의 고주파수 대역에서 내장형 소자에 대한 정확한 평가 및 특성 예측을 필요로 하게 된다. 본 연구에서는 고주파수 대역에서 내장형 소자들을 정확하게 측정할 수 있는 방법을 고찰하였는데 이 과정에서 여러 형태의 측정 지그를 비교 검토하여 최적화하였다.

• 한국정보통신설비학회:학술대회논문집
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• 한국정보통신설비학회 2007년도 학술대회
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• pp.27-30
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• 2007

This paper deals with an equivalent circuit model for RF passive components. Rational functions are obtained from the frequency responses of EM simulation by using Foster canonical partial fraction expressions. The Vector Fitting(VF) and the Adaptive Frequency Sampling(AFS) scheme are also implemented to obtain the rational functions. A passivity enforcement algorithm is applied to ensure the stability of the equivalent circuit model. In order to verify the schemes, S parameters of the equivalent circuit model is compared to those of EM simulation in case of the microstrip line structure with 3 slots in ground.

• Journal of Electrical Engineering and Technology
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• 제6권3호
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• pp.408-413
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• 2011

In this paper, a real-coefficient approach to Adaptive Frequency Sampling (AFS) technique is developed for efficient equivalent circuit modeling of RF components. This proposed method is advantageous than the vector fitting technique and the conventional AFS method in terms of fewer samples leading to a lower order of a rational function on a given data and to a direct conversion to an equivalent circuit for PSPICE(Personal Simulation Program with Integrated Circuit Emphsis) simulation, respectively. To validate the proposed method, the distributed equivalent circuit of a presented multi-layered RF low-pass filter is obtained using the proposed real-coefficient AFS, and then comparisons with EM simulation and circuit simulation for the device under consideration are achieved.

• 한국우주과학회:학술대회논문집(한국우주과학회보)
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• 한국우주과학회 2004년도 한국우주과학회보 제13권2호
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• pp.360-363
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• 2004

This review is concerned with the MP (multipactor) phenomena of the diplexer for RFDU DM of next generation satellite. The MP discharge is serious problems to design RF components in space applications such ase damage of physical structure, performance degradation, and mission failure of the satellite. In this work, we employed the 3D finite element method (FEM) to calculate the critical gap points and adopted ESTEC curve, MP susceptibility zone, to analyze the maximum handling RF power in the diplexer. And this work also recommends that one should design the tx filter of the diplexer which is more wider bandwidth upto the points to escape the ears of the group delay especially the cavity type of RF components in space applications.