• Title/Summary/Keyword: Waveguide

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CPW-fed Compact Slot Antenna Matched by T-shaped Stub (T형 스터브로 정합된 CPW급전 소형 슬롯 안테나)

  • Lee, Jong-Ig;Yeo, Jun-Ho
    • Journal of the Korea Academia-Industrial cooperation Society
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    • v.13 no.7
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    • pp.3140-3145
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    • 2012
  • In this paper, a design method for a compact slot antenna fed by a coplanar waveguide (CPW) is studied. A T-shaped tuning stub is inserted inside a narrow rectangular slot and the slot is impedance matched to the CPW feedline by adjusting the width, length, and position of the stub. The resonance frequency is adjustable by the slot length and the antenna size can be reduced by bending the slot. The resonance frequency and impedance matching property of the compact slot antenna are similar to those of the half-wavelength slot antenna, which enables one to design compact antenna of this type with ease. A compact slot antenna for 2.45-GHz ISM band is designed, fabricated on an FR4 substrate (dielectric constant of 4.4 and thickness of 0.8 mm), and experimentally tested. The measured results agree well with the simulations, which confirms the validity of this study. The fabricated compact slot antenna shows an impedance bandwidth of 200 MHz(2.32-2.52 GHz) for a VSWR < 2, which is suitable for 2.45-GHz ISM band (2.4-2.48 GHz). The measured radiation patterns show ${\infty}$-shaped directional pattern in the E-plane and nearly omni-directional pattern in the H-plane with a peak gain of 2.0 dBi, which are similar to those of a monopole antenna. The proposed antenna is expected to be suitable for the applications as antennas for WLAN, RFID, and mobile handset.

Cavity-type Beam Position Monitors for Future Accelerators (차세대 가속기용 공동형 빔위치 측정기 개발)

  • Kim S.H.;Park Y.J.;Hwang W.H.;Huang J.Y.;Honda Y.;Inoue Y.
    • Journal of the Korean Vacuum Society
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    • v.15 no.4
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    • pp.331-337
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    • 2006
  • Cavity-type beam position monitors were developed in collaboration with KEK to use for the future accelerators such as international linear collider (ILC) or x-ray free electron laser (XFEL) in PAL. BPM components such as BPM cavity, beam tubes, waveguides and feedthroughs were assembled by brazing at the same time to reduce mechanical errors during the fabrication. There are four screwed pins around outer rim of the cavity for the tuning of cavity frequency and x-y isolation. The resonance frequency of BPM is 6.422 GHz, the inner diameter of cavity is 53.822 mm, and the range of mechanical adjusting is $+ / - 250{\mu}m$. The x-y isolation was measured better than -40 dB after tuned. Test results of signal forms, x-y isolations, sensitivities are satisfied within requirements for the KEK ATF2 beam line.

Fabrication and analysis of $1.3\mum$ spot-size-converter integrated laser diodes (광모드변환기가 집적된 $1.3\mum$ SC-FP-LD 제작 및 특성 해석)

  • 심종인
    • Korean Journal of Optics and Photonics
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    • v.11 no.4
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    • pp.271-278
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    • 2000
  • We have fabricated and analyzed the lasing characteristics of 1.3$\mu\textrm{m}$ Spot-Size-Converter (SSC) integrated Fabry-Perot (FP) laser diodes, which are very promising light sources for optical subscriber networks. SSC-LDs has been developed by BIB (buttjoint-built-in) coupling and selective MOVPE growth. High-performances were achieved such as the slope efficiency from the SSC facet of 0.23-0.32 mW/mA, the full-width at the half maximum of the far-field pattern (FFP) of 9.5$^{\circ}$~12.3$^{\circ}$, the alignment tolerances of $\pm$2.3$\mu\textrm{m}$ and $\pm$2.5$\mu\textrm{m}$ within the extra-coupling loss of 1 dB for the vertical and parallel directions, respectively. These experimental results were compared to theoretical ones in order to clarify the operational problems and give a good design direction of the fabricated SSC-LDs. It was revealed that an asymmetric output power from the facets, an irrelevancy of FFP and the waveguide structure around SSC facet region, and a poor temperature characteristics were originated from the scattering in the BIB and SSC sections and SHB effect in the active section for the first time.t time.

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High Conversion Gain Millimeter-wave Monolithic Subharmonic Mixer With Cascode Harmonic Generator (Cascode형 하모닉 발생기를 이용한 고변환이득 특성의 밀리미터파 단일칩 Subharmonic 믹서)

  • An, Dan;Kim, Sung-Chan;Sul, Woo-Suk;Han, Hyo-Jong;Lee, Han-Shin;Uhm, Won-Young;Park, Hyung-Moo;Kim, Sam-Dong;Rhee, Jin-Koo
    • Journal of the Institute of Electronics Engineers of Korea TC
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    • v.40 no.5
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    • pp.197-203
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    • 2003
  • In this paper, we have presented millimeter-wave high conversion gain quadruple subharmonic mixers adopting the cascode harmonic generator The subharmonic mixers were successfully integrated by using 0.1 ${\mu}{\textrm}{m}$ GaAs pseudomorphic HEMTs(PHEMTs) and coplanar waveguide(CPW) structures. Measured output of 1st, 2nd and 4th harmonics of the fabricated cascode 4th harmonic generator are -21.42 dBm, -32.65 dBm and -13.45 dBm, respectively, for an input power of 10 dBm at 14.5 GHz. We showed that the highest conversion gain of 3.4 dB has obtained thus far at a LO power of 13 dBm from the fabricated subharmonic mixers. The millimeter-wave subharmonic mixer also ensure a high degree of isolation showing -53.6 dB in the LO-to-IF and -46.2 dB in the LO-to-RF, respectively, at a frequency of 14.5 GHz. The high conversion gain achieved in this work is the first report among the millimeter-wave subharmonic mixers.

A Study on the Design and Fabrication of Diplexer Using H-plane T-junction for KOREASAT-III Transponder (자계면 T-접합을 이용한 무궁화 III호 위성체용 다이플렉서의 설계 및 제작에 관한 연구)

  • 이용민;홍완표;신철재;강준길;나극환
    • The Journal of Korean Institute of Electromagnetic Engineering and Science
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    • v.10 no.4
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    • pp.582-593
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    • 1999
  • This paper presents the design and fabrication of the diplexer for a KOREASAT-III Ka-band satellite transponder. The transmission characteristics of the diplexer is analyzed by calculating the generalized scattering matrix using mode matching method. It is composed of 2 bandpass filters, coupled with H-plane T-junction having symmetrical inductive iris and E-plane metal insert structures. Compared with the size and weight of the Rx and Tx filter loaded with a transponders respectively, those of the diplexer can be effectively reduced. In a high power transmission, the variation of the filter characteristics is minimized by the scheme that irises are extended to the exterior of H-plane of the waveguide. This scheme needs no extra heat sinks for dissipating high power. The diplexer is designed to improve the simplification, durability and reliability by eliminating tuning screws, which have been used to compensate for the characteristics of fabricated filters. The bandpass filters of the diplexer show the insertion loss of less than 1.2 dB and the return loss in excess of 15 dB. The isolations of more than 65 dB have been achieved between Rx and Tx filter.

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A Evaluation of the Maximum Power of the 94 GHz Gunn Diode Based on the Measured Oscillation Power (발진출력 측정을 통한 94 GHz Gunn Diode의 최대 전력 조사)

  • Lee, Dong-Hyun;Yeom, Kyung-Whan;Jung, Myung-Suk;Chun, Young-Hoon;Kang, Yeon-Duk;Han, Ki-Woong
    • The Journal of Korean Institute of Electromagnetic Engineering and Science
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    • v.26 no.5
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    • pp.471-482
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    • 2015
  • In this paper, design and implementation of the 94 GHz Gunn oscillator and the evaluation of the maximum power of the Gunn diode used in the oscillator are presented. The 94 GHz Gunn oscillator is used InP Gunn diode and designed employing a WR-10 waveguide. The designed oscillator is fabricated through machining and its performance is measured. The fabricated oscillator shows an oscillation frequency of 95 GHz, output power of 12.64 dBm, and phase noise of -92.7 dBc/Hz at 1 MHz offset frequency. To evaluation the maximum power of the InP Gunn diode used in oscillator, the oscillator structure is modified to a structure having a diaphram. The height of thick diaphram which is used in the oscillator is varied. As a result, an oscillator has several different load impedances, which makes it possible to plot $G_L-V^2$ plot at the post plane. Using the $G_L-V^2$ plot, the maximum power of used Gunn diode including post is computed to be 16.8 dBm. Furthermore using the shorted and zero bias Gunn diode, the post loss used for DC biasing can be computed. Using the two losses, The maximum power of a InP Gunn diode is computed to be 18.55 dBm at 95 GHz. This result is close to a datasheet.

Studies on the High-gain Low Noise Amplifier for 60 GHz Wireless Local Area Network (60 GHz 무선 LAN의 응용을 위한 고이득 저잡음 증폭기에 관한 연구)

  • 조창식;안단;이성대;백태종;진진만;최석규;김삼동;이진구
    • Journal of the Institute of Electronics Engineers of Korea SD
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    • v.41 no.11
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    • pp.21-27
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    • 2004
  • In this paper, millimeter-wave monolithic integrated circuit(MIMIC) low noise amplifier(LNA) for V-band, which is applicable to 60 GHz wireless local area network(WLAN), was fabricated using the high performance 0.1 ${\mu}{\textrm}{m}$ $\Gamma$-gate pseudomorphic high electron mobility transistor(PHEMT). The DC characteristics of PHEMT are drain saturation current density(Idss) of 450 mA/mm and maximum transconductance(gm, max) of 363.6 mS/mm. The RF characteristics were obtained the current gain cut-off frequency(fT) of 113 GHz and the maximum oscillation frequency(fmax) of 180 GHz. V-band MIMIC LNA was designed using active and passive device library, which is composed of 0.1 ${\mu}{\textrm}{m}$ $\Gamma$-gate PHEMT and coplanar waveguide(CPW) technology. The designed V-band MIMIC LNA was fabricated using integrated unit processes of active and passive device. The measured results of V-band MIMIC LNA are shown S21 gain of 21.3 dB, S11 of -10.6 dB at 60 GHz and S22 of -29.7 dB at 62.5 GHz. The measured result of V-band MIMIC LNA was shown noise figure (NF) of 4.23 dB at 60 GHz.

A 2 GHz Compact Analog Phase Shifter with a Linear Phase-Tune Characteristic (2 GHz 선형 위상 천이 특성을 갖는 소형 아날로그 위상천이기)

  • Oh, Hyun-Seok;Choi, Jae-Hong;Jeong, Hae-Chang;Heo, Yun-Seong;Yeom, Kyung-Whan
    • The Journal of Korean Institute of Electromagnetic Engineering and Science
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    • v.22 no.1
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    • pp.114-124
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    • 2011
  • In this paper, we present a 2 GHz compact analog phase shifter with linear phase-tune characteristic. The compact phase shifter was designed base on a lumped all pass network and implemented using a ceramic substrate fabricated with thin-film technique. For a linear phase-tune characteristic, a capacitance of the varactor diode for a tuning voltage was linearized by connecting series capacitor and subsequently produced an almost linear capacitance change. The inductor and bias circuit in the all pass network was implemented using a spiral inductors for small size, which results in the size reduction to $4\;mm{\times}4\;mm$. In order to measure the phase shifter using the probe station, two CPW pads are included at the input and output. The fabricated phase shifter showed an insertion loss of about 4.2~4.7 dB at 2 GHz band and a total $79^{\circ}$ phase change for DC control voltage from 0 to 5 V, and showed linear phase-tune characteristic as expected in the design.

Development and Manufacture of W-band MMIC Chip and manufacture of Transceiver (W-대역 MMIC 칩 국내 개발 및 송수신기 제작)

  • Kim, Wansik;Jung, Jooyong;Kim, Younggon;Kim, Jongpil;Seo, Mihui;Kim, Sosu
    • The Journal of the Institute of Internet, Broadcasting and Communication
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    • v.19 no.6
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    • pp.175-181
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    • 2019
  • For the purpose of Application to the small radar sensor, the MMIC Chip, which is the core component of the W-band, was designed in Korea according to the characteristics of the transceiver and manufactured by 0.1㎛ GaAs pHEMT process, and compared with the MMIC chip purchased overseas. The noise figure of low noise amplifier, insertion loss of the switch and image rejection performance of the down-converted mixer MMIC chip showed better characteristics than those of commercial chips. The MMIC chip developed in domestic was applied to the transmitter and receiver through W-band waveguide low loss transition structure design and impedance matching to verify the performance after the fabrication is 9.17 dB, which is close to the analysis result. As a result, it is judged that the transceiver can be applied to the small radar sensor better than the MMIC chip purchased overseas.

테라헤르츠 펄스 기술

  • Han, Hae-Ok;Yu, Nan-Lee;Jeon, Tae-In;Jin, Yun-Sik;Park, Ik-Mo;Kim, Jeong-Hoe;Mun, Gi-Won;Han, Yeon-Ho;Jeong, Eun-A;Gang, Cheol;Lee, Yeong-Rak;Go, Do-Gyeong;Lee, Ui-Su;Ji, Young-Bin;Kim, Geun-Ju;Han, Gyeong-Ho
    • The Proceeding of the Korean Institute of Electromagnetic Engineering and Science
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    • v.19 no.5
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    • pp.87-103
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    • 2008
  • In recent years, the field of THz photonics based on THz pulse technology has gained tremendous, world-wide interest as a new exciting research subject. With a possibility of many commercial applications as well as fundamental scientific achievements in the field, many advanced nations are stepping up their effort in advancing the field of THz photonics. This fact is supported by the observation of the significant increase in the number of papers on THz pulse technology presented in renowned international journals and conferences. The subject that is interesting for the THz application is the development of THz pulse sources and detectors, and other passive devices. In this paper, we present a brief review on some of the key devices and their relavant measurement techniques such as THz photoconductive antennas, optical rectification, difference frequency geneneration with quasi-phase matching structures, electro-optic sampling, high speed real time measurements, THz transmission lines, and other various waveguide structures.