• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2013.05a
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• pp.766-767
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• 2013

본 논문에서는 차량 충돌 예방 레이더 시스템-온-칩용 24GHz 믹서(Mixer)를 제안한다. 이러한 회로는 24GHz의 동작주파수를 가지며, Gilbert 셀 구조로 구성된다. 이러한 회로는 TSMC $0.13{\mu}m$ 혼성신호/고주파 CMOS 공정 ($f_T/f_{MAX}=120/140GHz$)으로 설계되어 있다. 제안한 회로는 10.96dB의 변환이득으로 최근 발표된 연구결과 중 가장 우수한 수치를 보였다. 또한 7.62dBm의 우수한 IIP3의 특성과 -43.64dB의 입력/출력 반사손실 (S11/S22) 및 -49.3dB의 LO-RF간 격리 특성 (S12)으로 기존 연구결과 중 가장 우수한 결과를 각각 보였다.

• International Journal of Air-Conditioning and Refrigeration
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• v.13 no.2
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• pp.61-70
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• 2005

This study treats the numerical analysis of performance and design for plume abatement wet/dry cooling tower with a dry type heat exchanger. A two-dimensional analysis is performed using the finite volume method for mechanical draft counterflow and crossflow tower. For a coupling problem between water and air system, a turbulent two phase flow is considered. The Effectiveness-NTU method is used for modeling of the dry type heat exchanger. The parametric simulations such as the relative flowrate of air and attachment length of an air mixer are performed to examine the effect on plume abatement. It is found that if the relative air flowrate ratio and the adequate air mixer type are chosen well in addition to the ratio of water to air flowrate, the loss of cooling capacity and the additional cost are reduced and the plume is abated.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2013.10a
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• pp.708-709
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• 2013

본 논문에서는 차량 충돌 예방 레이더 시스템-온-칩용 24GHz 믹서(Mixer)를 제안한다. 이러한 회로는 24GHz의 동작주파수를 가지며, Gilbert 셀 구조로 구성된다. 이러한 회로는 TSMC $0.13{\mu}m$ 혼성신호/고주파 CMOS 공정 ($f_T/f_{MAX}=120/140GHz$)으로 설계되어 있다. 제안한 회로는 10.96dB의 변환이득으로 최근 발표된 연구결과 중 가장 우수한 수치를 보였다. 또한 7.62dBm의 우수한 IIP3의 특성과 -43.64dB의 입력/출력 반사손실 (S11/S22) 및 -49.3dB의 LO-RF간 격리 특성 (S12)으로 기존 연구결과 중 가장 우수한 결과를 각각 보였다.

• Journal of Positioning, Navigation, and Timing
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• v.3 no.3
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• pp.91-97
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• 2014

A direct RF sampling method refers to a technique that directly converts a passband signal to an intermediate band or a baseband without using a mixer. This method is less complicated than an existing RF receiver because a mixer is not used. It uses digital processing after sampling, and thus can flexibly process signals in a number of bands using software. In this process, it is important to select an appropriate sampling frequency so that a number of signals can be converted to an intermediate band that is easy to process. In this study, going beyond previously studied direct RF sampling frequency selection methods, conditions that need to be additionally considered during receiver design were examined, and the structure of a direct RF sampling receiver that satisfies these conditions was suggested.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2011.05a
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• pp.131-132
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• 2011

This study analyzes the yearly-best delivered size range of truck mixer based on the specified mix, Water to Binder Ratio, aggregate proportion and unit amount with statistical method targeting on Kyeongi and Kyeongsang province and compares with the similar materials of Japan to propose as a basic standard for the quality control of mixer truck. As a result, in case of the Water to Binder Ratio of these areas, it is higher than Japan's due to the excessive safety rate reflecting the changes of differential value impact and unit amount, and the unit amount's standard deviation is very large by reflecting the changes of the amount used and chemical admixture susceptibility. In case of aggregate proportion, the frequency rate is about 50%, which is very similar value with Japan's one.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.12 no.1
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• pp.65-70
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• 2001

This paper presents a Receiver MMIC for the CDMA terminal. The complete circuit is composed of Low Noise Amplifier, Down Conversion Mixer, Intermediate Frequency Amplifier and Bias circuit. The Bias circuit implementation, which allows for compensation for threshold voltage and power supply voltage variation are provided. The proposed topology has high linearity and low noise characteristics. Results of the designed circuit are as follows: Overall conversion gain is 28.5 dB, input IP3 of LNA is 8 dBm, input IP3 of down conversion mixer is 0 dBm and total DC current consumption is 22.1 mA.

• 한국정보통신설비학회:학술대회논문집
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• 2008.08a
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• pp.89-92
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• 2008

CMOS 기반의 고주파 집적회로에서는 높은 이득과 출력을 얻기 위하여 인덕터와 같은 수동소자를 사용한다. 그러나 수동소자를 사용하게 되면 넓은 면적을 차지하기 때문에 회로의 크기를 증가시키는 단점을 갖는다. 본 논문에서는 PMOS 를 기반으로 구현한 active inductor 를 적용하여 회로의 면적을 줄일 수 있으며, 기존의 주파수 변환기와 동등한 선형 특성을 갖는 상향 주파수 변환기를 설계하였다. 인덕터를 적용한 상향 주파수 변환기의 OIP3 ($3^{rd}$ Output Intercept Point)는 1.3 dBm 을 가지며, 제안한 상향 주파수 변환기의 OIP3 는 0.8 dBm 으로 동등한 선형 특성을 보이며, layout 상에서 회로의 면적을 40 % 이상 감소하는 특성의 선형 송신기용 주파수 변환기를 설계 분석하였다.

• Proceedings of the KIEE Conference
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• 2009.07a
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• pp.1565_1566
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• 2009

This paper presents the design and analysis of RF Front End for Wireless Heartbeat measurement System. In this work LNA, an inductor connected at the gate of the cascode transistor and capacitive cross-coupling are strategically combined to reduce the noise and the nonlinearity influences of the cascode transistors in a differential LNA. The Mixer is implemented by using the Gilbert-type configuration, cross pmos injection technique and the resonating technique for the tail capacitance. The resulting LNA achieves 1.26dB NF, better than 1.88dB NF Typical. Also Mixer resulting achieves 9.8dB at 100KHz.

• Proceedings of the KIEE Conference
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• 2003.07c
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• pp.1958-1960
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• 2003

Here we describe a unique self-oscillating mixer (SOM) design using a modified defected ground structure (DGS) for down-converter. Proposed SOM is consisted of self-oscillator, which can produce negative resistance and select resonance frequency, and input/output matching filter. As the advantage of this SOM can be reused by module that mix signals with transistor that is used to oscillator, it is simply and low-costly designed Also, there is easy advantage to be applied in RFIC/ MMIC technology because it offers excellent high Q value in spite of using micro-strip structure. Designed self-oscillating frequency is 1.04GHz and RF frequency established is 0.8GHz. It was achieved 20dB conversion loss and phase noise of -95dBc/Hz at 100KHz offset frequency over intermediate frequency (IF). The equivalent circuit parameters for DGS are extracted by using a three dimensional EM simulator and simple circuit analysis method.

• 제어로봇시스템학회:학술대회논문집
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• 2000.10a
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• pp.275-275
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• 2000

This paper designs a digital correlator for the integrated GPS/GLONASS receiver consisting of DCO, carrier cycle counter, code generator, code phase counter, mixer, epoch counter, accumulator. It is designed using Verilog-HDL(Verilog-Hardware Description Language) and synthesized using EDA(Electronic Design Automation) tools. The performance of the designed digital correlator is verified by the functional simulation and real satellite tracking experiments.