• Title/Summary/Keyword: S-band

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S-Band Internally-Matched High Efficiency and High Power Amplifier Using GaN HEMT Die (GaN HEMT Die를 이용한 S-대역 내부 정합형 고효율 고출력 증폭기)

  • Kim, Sang-Hoon;Choi, Jin-Joo;Choi, Gil-Wong;Kim, Hyoung-Joo
    • The Journal of Korean Institute of Electromagnetic Engineering and Science
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    • v.26 no.6
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    • pp.540-545
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    • 2015
  • This paper presents the design, fabrication and measurement results of a S-band internally-matched power amplifier using Gallium Nitride High Electron Mobility Transistor(GaN HEMT) die. In order to fabricate the S-band internally-matched power amplifier, a high dielectric substrate and alumina were used for input/output matching circuits. The measured output power is 55.4 dBm, the drain efficiency is 78 % and the power gain is 11 dB under pulse operation at the frequency of 3 GHz.

Surface Reconstruction on Hydrogen Covered W(011) (수소가 흡착된 W(011) 표면의 재구성)

  • 김희봉;최원국;홍사용;황정남;정광호
    • Journal of the Korean Vacuum Society
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    • v.1 no.1
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    • pp.83-87
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    • 1992
  • Rencently, angle-resolved ultraviolet photoemission measurements of the Fermi surface contours for Mo(011) and W(011) are reported. The electron contour of W(011) is expanded upon hydrogen adsorption, which implies that the surface states consisting of electron pockets are shifted to higher binding energy. This phenomena can be explained by the band flattening. We explained here the reconstruction of W(011) surface induced by adsorption of hydrogen in terms of band flattening of surface states with a combination of S. E. Trullinger long range dipole-dipole interaction force and Kohn anomaly.

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A Study on KNU Direct Sequence Spread Spectrum Transmission Device Embodiment (KNU DSSS 전송장치 구현에 관한 연구)

  • Kim, Yong-Tae
    • The Journal of Information Technology
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    • v.5 no.2
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    • pp.47-54
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    • 2002
  • OFDM ambient noise and entrain error that this research proposes in IEEE 802.11g, use 256-State 2/3 binary scale Convoulutional 8-PSK Modulations, FEC coding, PBCC and did speed of 12 Mbpses that belong on category of 5 GHzs Band FHSS way so that can be applied in 20 Mbpses DSSS'S generalization that is establishing Pyojunan in current IEEE embodying transmission device model who operate with the equal speed from 2.4 GHzs ISM Band important duty to DSSS way.

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V-band CPW receiver chip set using GaAs PHEMT (GaAs PHEMT를 이용한 V-band CPW receiver chip set 설계 및 제작)

  • W. Y. Uhm;T. S. Kang;D. An;Lee, B. H.;Y. S. Chae;Park, H. M.;J. K. Rhee
    • Proceedings of the Korea Electromagnetic Engineering Society Conference
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    • 2002.11a
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    • pp.69-73
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    • 2002
  • We have designed and fabricated a low-cost, V-band CPW receiver chip set using GaAs PHEMT technology for the application of millimeter-wave wireless communication systems. Low noise amplifiers and down-converters were developed for this chip set. The fabricated low noise amplifier showed an S$\sub$21/ gain of 14.9 ㏈ at 60 ㎓ and a noise figure of 4.1 ㏈ at 52 ㎓. The down-converter exhibited a high conversion gain of 2 ㏈ at the low LO Power of 0 ㏈m. This work demonstrates that the GaAs PHEMT technology is a viable low-cost solution for V-band applications.

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E-band low-noise amplifier MMIC with impedance-controllable filter using SiGe 130-nm BiCMOS technology

  • Chang, Woojin;Lee, Jong-Min;Kim, Seong-Il;Lee, Sang-Heung;Kang, Dong Min
    • ETRI Journal
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    • v.42 no.5
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    • pp.781-789
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    • 2020
  • In this study, an E-band low-noise amplifier (LNA) monolithic microwave integrated circuit (MMIC) has been designed using silicon-germanium 130-nm bipolar complementary metal-oxide-semiconductor technology to suppress unwanted signal gain outside operating frequencies and improve the signal gain and noise figures at operating frequencies. The proposed impedance-controllable filter has series (Rs) and parallel (Rp) resistors instead of a conventional inductor-capacitor (L-C) filter without any resistor in an interstage matching circuit. Using the impedance-controllable filter instead of the conventional L-C filter, the unwanted high signal gains of the designed E-band LNA at frequencies of 54 GHz to 57 GHz are suppressed by 8 dB to 12 dB from 24 dB to 26 dB to 12 dB to 18 dB. The small-signal gain S21 at the operating frequencies of 70 GHz to 95 GHz are only decreased by 1.4 dB to 2.4 dB from 21.6 dB to 25.4 dB to 19.2 dB to 24.0 dB. The fabricated E-band LNA MMIC with the proposed filter has a measured S21 of 16 dB to 21 dB, input matching (S11) of -14 dB to -5 dB, and output matching (S22) of -19 dB to -4 dB at E-band operating frequencies of 70 GHz to 95 GHz.

Changes in Ultrastructure of Tissues, Characteristics of Protein and Soybean Curd Yield with Increased Soaking Time during Soybean Curd Processing (대두(大豆)의 수침시간(水浸時間)에 따른 조직(組織)의 미세구조(微細構造), 단백질(蛋白質) 특성(特性) 및 두부수율(豆腐收率)의 변화(變化))

  • Park, Yong-Gone;Park, Boo-Duck;Choi, Kwang-Soo
    • Journal of the Korean Society of Food Science and Nutrition
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    • v.14 no.4
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    • pp.381-386
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    • 1985
  • This experiment was conducted to investigate changes of soybean curd yield according to the extension of soaking time during manufacturing of soybean curd. To investigate those changes systematically, transmission electron microscopy and disc-gel electrophoresis were used. The soybean curd yield was increased from 45.0% to 50.5% and 55.4% respectively as soaking time is extended from 5 hours to 10 and 24 hours. The solid extraction and soybean milk coagulation were also increased according to the extension of soaking time. From disc-gel electrophoresis patterns of soybean milk protein and soybean curd protein, numbers of band were increased and major band thickened by expending the soaking time. Most of high molecular bands of soybean milk protein were transfered to soybean curd. Crude 7S proteins of soybean milk and soybean curd in dis-gel electrophoresis were appeared to be 4 and 5 bands respectively, and crude 11S proteins of soybean milk and soybean curd were appeared to be 9 and 8 bands respectively. Of soybean milk bands, most of 11S component transfered to soybean curd. Transmission electron photomicrographs revealed that the dimension of each protein body became larger and the numbers of spherosome around the protein bodies in unit area fewer by extending the soaking time of soybean.

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Femtosecond degenerate and nondegenerate pump-probe experiments in bulk GaAs below the band gap

  • Yahng, J. S.;Kim, D. S.;Fatti, N.Del;Vallee, F.
    • Journal of the Optical Society of Korea
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    • v.1 no.2
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    • pp.100-103
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    • 1997
  • We perform degenerate and nondegenerate pump-probe experiments on bulk GaAs at 100 K below the band gap. We mostly observe a negative differential transmission signal both in the degenerate and nondegenerate experiments. We interpret our signal as due to two-photon absorption. This negative signal has a different origin from the normally considered band gap renormalization for resonant excitations.

Studies on the Design and Fabrication of MMIC Power Amplifier for X-band (X-band용 MMIC 전력증폭기의 설계 및 제작에 관한 연구)

  • 이성대;이호준;이응호;윤용순;박현식;이진구
    • Proceedings of the IEEK Conference
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    • 1999.11a
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    • pp.159-162
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    • 1999
  • In this paper, we have designed and fabricated a MMIC power amplifier for X-band using AlGaAs/InGaAs/GaAs PM-HEMTs and passive devices such as Ti thin film resistors, rectangular spiral inductors and MIM capacitors. The fabricated MMIC power amplifier for X-band shows that S/ sub 21/ and S$_{11}$ are 14.804 ㏈ and -29.577 at 8.18 GHz, respectively. The chip size is 1.86$\times$1.29 $\textrm{mm}^2$.>.>.

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Comparisons of Isozyme Patterns in Pythium Species and Application to Pythium Systematics (Isozyme을 이용한 Pythium species의 비교 및 Pythium systematics에의 이용)

  • Lee, Youn-Su
    • The Korean Journal of Mycology
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    • v.21 no.4
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    • pp.293-300
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    • 1993
  • For the enzymes AAT, GmDH, ME, GPI, LDH and IDH, nine, seven, four, nine, seven, and four different phenotypes, respectively, were observed. All six isolates of an unidentified sterile Pythium sp. isolated from field soil showed the same band positions for all six enzymes compared. These phenotypes were not similar to any of the known Pythium species. Two isolates of unknown Pythium species (145 and 299) showed the same band positions for all six enzymes. The phenotypes for all three unknown Pythium spp. were different from the other species in the experiment. Five isolates of P. heterothallicum showed the same band positions for all enzymes compared except one enzyme, lDH. Two isolates of P. torulosum showed the same band petitions for enzymes AAT, GmDH and ME, and three isolates of P. totulosum showed the same positions for enzymes GPI, LDH, and IDH. Single isolates of P. spinosum and P. irregulare showed the same band positions for enzymes AAT, GmDH and GPI. In conclusion, sterile types of Pythium species showed 100% similarities among themselves but did not show any similarity with all isolates of P. heterothallicum and P. spinosum isolate, and showed very low similarities with other isolates in general except with unknown Pythium isolate 306. Similarity levels between different species were low in general with few exceptions.

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POTENTIAL OF MULTI-BAND SAR DATA FOR CLASSIFYING FOREST COVER TYPE

  • Shin, Jung-Il;Yoon, Jong-Suk;Kang, Sung-Jin;Lee, Kyu-Sung
    • Proceedings of the KSRS Conference
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    • 2007.10a
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    • pp.258-261
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    • 2007
  • Although there have been lack of studies using X-band SAR data particularly for forestry application as compared to C-, and L-band SAR data, it has a potential to distinguish tree species because most signals are backscattered on the top of canopy. This study aimed to compare signal characteristics of multi-band SAR data including X-band for classifying tree species. The data used for the study are SIR-C/X-SAR data (X-, C-, L-band) obtained on Oct. 3, 1994 over the forest area near Seoul, S. Korea. Thirty ground sample plots were collected per each tree species. Initial comparison of backscattering coefficients among three SAR bands shows that X-band data showed better separation of tree species than C- and L-band SAR data irrespective of polarization. The weak penetrating in canopy layer might be possible source of information for X-band data to be useful for the classification of forest species and cover type mapping.

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