• Title/Summary/Keyword: RF phase

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Design and Fabrication of RF Receiver Module for IMT-2000 Handset (IMT-2000 단말기용 RF 수신모듈 설계 및 제작)

  • 황치전;이규복;박인식;박규호;박종철
    • Proceedings of the IEEK Conference
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    • 1999.11a
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    • pp.817-820
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    • 1999
  • In this paper, we describes RF receiver module for IMT-2000 handset with 5MHz channel bandwidth. The fabricated RF receiver module consists of Low Noise Amplifier-, RF SAW filter, Down-converter, IF SAW filter, AGC and PLL Synthesizer. The NF and IIP3 of LNA is 0.8㏈, 3㏈m at 2.14㎓, conversion gain of downconverter is l0㏈, dynamic range of AGC is 80㏈, and phase noise of PLL is -100 ㏈m, at 100KHz. The receiver sensitivity is -110㏈m, adjacent channel selectivity is -48㏈m.

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Oxidation of Amorphous BON Thin Films Grown by RF-PECVD (RF-PECVD 법으로 제조된 비정질 BON박막의 산화)

  • Kim J. W.;Boo J.-H.;Lee D. B.
    • Korean Journal of Materials Research
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    • v.14 no.10
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    • pp.683-687
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    • 2004
  • The BON thin films were grown on the Si substrate by the RF-PECVD method. When stored at the room temperature, the phase separation or transition of BON thin films occurred on the surface, due to the hydrophilic property of BON. The oxidation of BON thin films occurred mainly by the evaporation of B, O and N. The oxidized BON thin films consisted of an amorphous phase and a bit of the polycrystalline phase.

A Method for Reduction of Spurious Signal in Digital RF Memory (디지털 고주파 기억 장치에서의 스퓨리어스 신호 저감 방법)

  • Kang, Jong-Jin
    • The Journal of Korean Institute of Electromagnetic Engineering and Science
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    • v.22 no.7
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    • pp.669-674
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    • 2011
  • In this paper, a method for reduction of spurious signal in Digital RF Memory(DRFM) is proposed. Spurious response is a major performance issue of DRFM. This method is based on mixing a random phase LO signal into input IF signal and sampling it. The random phase LO signal is generated by high speed phase shifting characteristic of Direct Digital Synthesizer(DDS). Through this technique, we achieved an enhancement of 5~10 dB of spurious response.

RF Oscillator Improved Characteristics of Phase Noise Using Ring type DGS (위상잡음을 개선한 링형 DGS 공진기를 이용한 RF 발진기)

  • Kim, Gi-Rae
    • Journal of the Korea Institute of Information and Communication Engineering
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    • v.16 no.8
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    • pp.1581-1586
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    • 2012
  • In this paper, a novel resonator using ring type DGS is proposed for improvement of phase noise characteristics that is weak point of oscillator using planar type microstrip line resonator, and oscillator for 5.8GHz band is designed using proposed DGS resonator. The ring type DGS resonator is composed of DGS cell etched on ground plane under $50{\Omega}$ microstrip line. At the fundamental frequency of 5.8GHz, 7.6dBm output power and -82.7 dBc@100kHz phase noise have been measured for oscillator with ring type DGS resonator. The phase noise characteristics of oscillator is improved about 9.5dB compared to one using the general ${\lambda}/4$ microstrip resonator. Because it is possible that varactor diode or lumped capacitor is placed on the gaps of ring type DGS, resonant frequency can be controlled by bias voltage. We can design voltage controlled oscillator using proposed ring type DGS resonator. Thus, due to its simple fabrication process and planar type, it is expected that the technique in this paper can be widely used for low phase noise oscillators for both MIC and MMIC applications.

Design of a New Harmonic Noise Frequency Filtering Down-Converter in InGaP/GaAs HBT Process

  • Wang, Cong;Yoon, Jae-Ho;Kim, Nam-Young
    • Journal of electromagnetic engineering and science
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    • v.9 no.2
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    • pp.98-104
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    • 2009
  • An InGaP/GaAs MMIC LC VCO designed with Harmonic Noise Frequency Filtering(HNFF) technique is presented. In this VCO, internal inductance is found to lower the phase noise, based on an analytic understanding of phase noise. This VCO directly drives the on-chip double balanced mixer to convert RF carrier to IF frequency through local oscillator. Furthermore, final power performance is improved by output amplifier. This paper presents the design for a 1.721 GHz enhanced LC VCO, high power double balance mixer, and output amplifier that have been designed to optimize low phase noise and high output power. The presented asymmetric inductance tank(AIT) VCO exhibited a phase noise of -133.96 dBc/Hz at 1 MHz offset and a tuning range from 1.46 GHz to 1.721 GHz. In measurement, on-chip down-converter shows a third-order input intercept point(IIP3) of 12.55 dBm, a third-order output intercept point(OIP3) of 21.45 dBm, an RF return loss of -31 dB, and an IF return loss of -26 dB. The RF-IF isolation is -57 dB. Also, a conversion gain is 8.9 dB through output amplifier. The total on-chip down-converter is implanted in 2.56${\times}$1.07 mm$^2$ of chip area.

A Study on Configuration of True Time Delay Phase Shifter for Wideband Beam Steering Phased Array Antenna (광대역 빔 조향을 위한 위상 배열 안테나의 실시간 지연 위상 천이기 구성에 관한 연구)

  • Jung, Jinwoo;Ryu, Jiho;Park, Jaedon;Seo, Jongwoo
    • Journal of the Korea Institute of Military Science and Technology
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    • v.20 no.3
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    • pp.413-420
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    • 2017
  • We investigate the performance of a true time delay(TTD) phase shifter to reduce the beam squint caused by frequency changes of a phased array antenna in wideband communication systems. To design a high gain phased array antenna, we need a long TTD, which causes high RF loss, low resolution and large dimension of TTD phase shifters. To overcome the problems, we propose a schematic of dual TTD phase shifters, which consists of short time delay(STD) in radio frequency(RF) part and long time delay(LTD) in intermediate frequency(IF) part. Our analysis results show that the proposed scheme reduces the required bits and delay time in RF band of the TTD compared to the conventional single TTD scheme.

Voltage-Controlled Photonic RF True-Time Delay Using a Tapered Chirped Fiber Bragg Grating (테이퍼 구조를 갖는 광섬유 브래그 격자를 이용한 전압에 의하여 제어 가능한 광학적 실시간 지연 소자)

  • Chae, Ho-Dong;Lee, Sang-Shin
    • Korean Journal of Optics and Photonics
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    • v.16 no.2
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    • pp.133-137
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    • 2005
  • A photonic RF true-time delay using a tapered chirped fiber Bragg grating coated with a heating electrode has been proposed and fabricated. For an RF signal carried over an optical signal, the time delay has been achieved by controlling the voltage applied to the electrode and thus adjusting its reflection positions from the fiber grating through the thermooptic effect. It features continuous voltage-controlled operation, requiring no mechanical perturbation and no moving parts. The measured time delay was about 120 ps with the electrical power consumption of $250{\cal}mW$.

The Characteristics of $TiO_2$ thin films on Working pressure of RF sputter (RF스퍼터 공정압력의 변화에 따른 $TiO_2$ 박막의 특성)

  • Jin, Young-Sam;Kim, Kyung-Hwan;Choi, Myung-Kyu;Choi, Wook-Hyung
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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    • 2009.06a
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    • pp.218-219
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    • 2009
  • $TiO_2$ thin films were deposited on si wafer and glass substrates by rf magnetron sputtering. The films were coated under argon atmosphere at different working pressures: 3mTorr, 5mTorr, 7mTorr, 10mTorr. The films were annealed at $550^{\circ}C$ for 5h after deposition. Film structures were analyzed with XRD, As the increase of working pressure, $TiO_2$ films have been good crystallinity. At 3mTorr and 5mTorr, the films were observed in rutile phase and anatase phase.

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Novel Flow Suppression Technique in MRI (핵자기 공명 영상에서 새로운 유속 흐름제거 방법)

  • Ro, Y.M.;Cho, Z.H.
    • Proceedings of the KOSOMBE Conference
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    • v.1992 no.05
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    • pp.92-97
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    • 1992
  • The pulsatile nature of blood flow makes artefacts in 2D Fourier transform image. Spatial presaturation is known to be effective in eliminating flow artefacts when the spin echo acquisition is employed. However. this method requires additional RF pulse and spoiling gradient for presaturation. In this paper a new flow saturation technique which does not require additional saturation-RF and gradient is proposed. The proposed technique is equivalent to the existing saturation technique but the elimination of the flow component is achieved by a pair of tailored $90^{\circ}-180^{\circ}$ RF pulses in tile spin echo sequence. By use of two tailored RF pulses with opposite phase polarity, a linear phase gradient is generated for those moving materials and consequently all the spins of moving materials become dephased thereby no signal is observable. Computer simulations and experimental results obtained using both a phantom and a human volunteer with a 2.0 T whole body system are also presented.

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A 950 MHz CMOS RF frequency synthesizer for CDMA wireless transceivers (CDMA 이동 통신 단말기용 950 MHz CMOS RF 주파수 합성기)

  • 김보은;김수원
    • Journal of the Korean Institute of Telematics and Electronics C
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    • v.34C no.7
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    • pp.18-27
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    • 1997
  • A CMOS 950 MHz frequency synthesizer is designed and fabricated in a 0.8.mu.m standard CMOS process for IS-95-A CDMA mobile communication transceivers To utilize a CMOS ring VCO in a CDMA wireless communication receisver, we employed a QDC (quasi-direct conversion) receiver architecture for CDMA applications. Realized RF frequency synthesizer used as the RF local oscillator for a QDC receiver exhibits a phase noise of -92 dBc/Hz at 885kHz offset from the 950.4 MHz carrier, which complies with IS-95-A CDMA specification. It has a rms jitter of 23.7 ps, and draws 30mA from a 5V supply. Measured I/Q phase error of the 950.4 output signals is 0.7 degree.

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