• Journal of the Institute of Electronics and Information Engineers
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• v.50 no.10
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• pp.41-49
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• 2013

This paper suggests the dielectric resonator antenna using LTCC process for mm-wave car radar system. In this paper, dielectric resonator antennas (DRA) operated in 76-77 GHz frequency band are designed. And, using the LTCC process, the structures of dielectric resonator with SRR (split ring resonator) inside and those of dielectric resonator with probe inside are suggested. Linear polarization antennas and circular polarization antenna are designed for the DRA with probe inside. Three kinds of the DRA antennas are designed and their characteristics are calculated using CST RF simulation tool. The designed antennas are fabricated and measured and the measured results are compared with calculated results. The measured operating frequencies of DRAs are within 76 GHz to 77 GHz, which are close to the calculated results, and the measured gains are about 8.15 dBi to 10.82 dBi.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.42 no.1
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• pp.25-30
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• 2017

Millimeter wave (mmWave) bands are expected to improve date rate of 5G systems due to the wide available bandwidth. While severe path loss in those bands has impeded the utilization, short wavelength enables a large number of antennas packed in a compact form, which can mitigate the path loss. However, estimating the channel with a conventional scheme requires a huge training overhead, hence an efficient estimation scheme operating with a small overhead needs to be developed. The sparsity of mmWave channels caused by the limited scatterers can be exploited to reduce the overhead by utilizing compressed sensing. In this paper, we introduce compressed sensing techniques for mmWave channel estimation. First, we formulate wideband channel estimation into a sparse recovery problem. We also analyze the characteristics of random measurement matrix constructed using quantized phase shifters in terms of mutual incoherence.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.12 no.7
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• pp.1191-1198
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• 2001

MMIC low noise amplifiers for millimeter-wave application using 0.15 $\mu$m pHEMT have been presented in this paper. The design emphasis is on active device model and EM simulation. The deficiency of conventional device models is identified. A distributed device model has been adapted to circumvent the scaling problems and, thus, to predict small signal and noise parameters accurately. Two single-ended low noise amplifier are designed using distributed active device model for Q-band(40 ∼ 44 GHz) and V-band(58 ∼65 GHz) application. The Q-band amplifier achieved a average noise figure of 2.2 dB with 18.3 dB average gain. The V-band amplifier achieved a average noise figure of 2.9 dB with 14.7 dB average gain. The design technique and model employed provides good agreement between measured and predicted results. Compared with the published data, this work also represents state-of-the-art performance in terms of gain and noise figure.

• Electronics and Telecommunications Trends
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• v.31 no.1
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• pp.58-67
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• 2016

이동통신 시스템은 무선 트래픽 공급의 양과 질 양면에서 눈부신 발전을 이루어왔다. 최근 스마트폰, 스마트패드 및 태블릿 pc 등 이동통신 기능을 가진 휴대용 스마트 기기의 급속한 대규모 보급과 늘어난 사용자 트래픽의 증가로 기존 3GHz 이하 대역에서 동작하는 이동통신 시스템은 통신 용량 측면에서 한계에 직면할 것으로 예상된다. 이에 우리나라를 비롯한 중국, 일본 등의 아시아와 유럽, 미국을 중심으로 가용 대역이 풍부한 mmWave의 5세대 이동통신 활용을 위한 연구 및 개발이 활발히 진행되고 있다. 본고에서는 mmWave 대역을 위한 5G 표준화 동향과 채널 모델링, mmWave 대역에서 사용될 것으로 예상되는 전송기술 및 현재까지 ETRI를 비롯한 여러 회사에서 개발되거나 개발 중인 mmWave 이동통신 시스템을 소개한다.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.27 no.5
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• pp.471-481
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• 2016

We introduce the design technique and test results of a millimeter-wave compact antenna test range. Physical optics is employed for the analysis of the plane wave collimated by an electrical large parabolic reflector of the compact range in the test zone. The performance of the manufactured compact range is verified with the field probing test on the quiet zone and the measurement of high gain antenna. A millimeter-wave compact range designed in the frequency range of 75~110 GHz with a diameter of the test zone of 50 cm shows the magnitude variation of less than 0.75 dB.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.30 no.1
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• pp.54-59
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• 2019

In this paper, we report on the waveguide-to-microstrip transition with an inline structure for the millimeter band. The waveguide-to-microstrip transition comprises a probe, an inductive line, a ${\lambda}/4$ impedance transformer, and a 50-ohm microstrip line. For the transition design, we optimized the characteristic impedances and lengths of the component parts. The fabricated transition exhibits an insertion loss of 2.1 dB and an input/output return loss of below 13 dB at a millimeter band frequency of 94 GHz.

• Journal of the Institute of Electronics Engineers of Korea SD
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• v.39 no.10
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• pp.9-15
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• 2002

We propose a new transit time device to extend the operating frequency to submillimeter-wave(extreme infrared) ranges by utilizing velocity overshoot effects in the drift region. We name it a velocity overshoot transit time (OVTT) diode. This device adopts fast heterostructure tunneling as injection mechanism and a short drift region to optimize the velocity overshoot effects. To enhance dc-to-RF conversion efficiencym the drift region is designed with a bandgap grading method. Simulation results demonstrate that a VOTT diode can be operated at THz ranges.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2000.05a
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• pp.195-198
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• 2000

This paper have been analyzed performance of DS-CDMA/QPSK system in short range IVC, and evaluated packet uu rate(PER) in an On-Ray Rician channel model suitable for platoon driving of AVHS that 60GHz millimeter wave is very powerful to MP(multipath-wave). We analyzed probability characteristic of system as variation of Rician factor and user number in One-Ray Rician fading environment and evaluated packet error rate(PER) according to inter-vehicle distance when the BCH channel coding(255,247,1) and diversity schemes is adopted.

• Electronics and Telecommunications Trends
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• v.20 no.6 s.96
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• pp.15-23
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• 2005

최근 국내외에서 연구되고 있는 가입자에 초고속 멀티미디어 서비스가 가능하도록pico cell 가입자 통신망을 구성하여 100Mbps-수 Gbps의 대용량 초고속 데이터를 통신할 수 있는 밀리미터파 pico cell 광무선 통신 기술의 개념, 필요성, 기술 동향과ETRI를 중심으로 연구 개발되고 있는 핵심 부품들의 개발 현황과 기술의 활용성에 대하여 조사하였다.

• Journal of the Korea Society of Computer and Information
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• v.5 no.4
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• pp.55-61
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• 2000

The ITU-R model for cross-polarization due to rain is applicable only upto 3.5GHz. The scattering characteristics of rain drops are analyzed by an analytical model. A simple theoretical model for croee-polarization, which is accurate enough in real rainfall environments. is Proposed in this Paper. By comparing this with measurement data and the ITU-R, we have also derived an prediction model for rain cross-polarization applicable upto millimeter wave band.