• Title/Summary/Keyword: LO leakage

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A Novel Method to Reduce Local Oscillator Leakage (국부발진기에서의 누설신호의 새로운 제거방식)

  • 이병제;강기조
    • The Journal of Korean Institute of Electromagnetic Engineering and Science
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    • v.11 no.2
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    • pp.294-301
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    • 2000
  • One of the most important design parameters in a microwave radio transmitting system is to reduce spurious response from the output spectrum of the transmitting system. A Local oscillator (LO) is seldom totally pure and at the least contain some LO harmonic signals. A LO or any oscillator is a transmitter if provided with a suitable radiator, conduction, or leakage path. Where mixer is employed in the output of the LO mixer generated spurs can be increased by RF amplifier. To reduce LO leakage, notch filter or band pass filter has been conventionally used. In this paper, the leakage reduction(LR) signal, which has the same magnitude and the opposite phase with respect to LO leakage signal, is added to the output of mixer of the wireless LAN system. The LO leakage is reduced by 30 dB more than the conventional methods do. The proposed method is potentially suitable for low-cost, reliable, and simple application of monolithic microwave integrated circuits (MMICs)

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The Design of a Sub-Harmonic Dual-Gate FET Mixer

  • Kim, Jeongpyo;Lee, Hyok;Park, Jaehoon
    • Journal of electromagnetic engineering and science
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    • v.3 no.1
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    • pp.1-6
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    • 2003
  • In this paper, a sub-harmonic dual-gate FET mixer is suggested to improve the isolation characteristic between LO and RF ports of an unbalanced mixer. The mixer was designed by using single-gate FET cascode structure and driven by the second harmonic component of LO signal. A dual-gate FET mixer has good isolation characteristic since RF and LO signals are injected into gatel and gate2, respectively. In addition, the isolation characteristic of a sub-harmonic mixer is better than that of a fundamental mixer due to the large frequency separation between the LO and RF frequencies. As RF power was -30 ㏈m and LO power was 0 ㏈m, the designed mixer yielded the -47.17 ㏈m LO-to-RF leakage power level, 10 ㏈ conversion gain, -2.5 ㏈m OIP3, -12.5 ㏈m IIP3 and -1 ㏈m 1 ㏈ gain compression point. Since the LO-to-RF leakage power level of the designed mixer is as good as that of a double-balanced mixer, the sub-harmonic dual-gate FET mixer can be utilized instead.

Design of a sub-harmonic dual-gate FET mixer for IMT-2000 base-station

  • Kim, Jeongpyo;Park, Jaehoon
    • Proceedings of the IEEK Conference
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    • 2002.07b
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    • pp.1046-1049
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    • 2002
  • In this paper, a sub-harmonic dual-gate FET mixer for IMT-2000 base-station was designed by using single-gate FET cascode structure and driven by the second order harmonic component of LO signal. The dual-gate FET mixer has the characteristic of high conversion gain and good isolation between ports. Sub-harmonic mixing is frequently used to extend RF bandwidth for fixed LO frequency or to make LO frequency lower. Furthermore, the LO-to-RF isolation characteristic of a sub-harmonic mixer is better than that of a fundamental mixer because the frequency separation between the RE and LO frequency is large. As RF power is -30dBm and LO power is 0dBm, the designed mixer shows the -47.17dBm LO-to-RF leakage power level, 10dB conversion gain, -0.5dBm OIP3, -10.5dBm IIP3 and -1dBm 1dB gain compression point.

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Development and Performance Test of Online Electrical Safety Monitoring System Applying an Algorithm to Measure Resistive Leakage Currents using Phase Differences (위상차를 이용한 저항성 누설전류 측정 알고리즘을 적용한 온라인 전기안전 감시시스템의 개발 및 성능시험)

  • Yoo, Jeong Hyun;Kim, Hie Sik;Jeong, Yong Wook
    • Journal of the Korean Society of Safety
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    • v.33 no.3
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    • pp.27-32
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    • 2018
  • Nowadays, to prevent electrical accidents in Korea, inspectors directly performed checking general electrical facilities as a cycle from every one to three years. It is difficult to presuppose an omen because intact conditions of electrical equipments are not kept at the time of inspection. In this paper, in order to ensure effectiveness of an online basis electric inspection, we developed an electrical safety IoT system using LoRa communication technology to enable monitoring mainly electrical safety components such as overcurrent, overvoltage, resistive leakage current, and power. Then we proposed a method for verifying performances of the prosed electrical safety IoT system. Resistive leakage currents are calculated by using difference of phase between voltages and currents. We verified that average errors are 0.97%, which reference goal is ${\pm}5%$ for a device, through reliability test according to conditions. Results of this research can be used as basic study materials to develop technologies for measuring three phase leakage current and for implementing public electrical safety. platform.

Local Oscillator Leakage Rejection For Satellite Communication Intermediate Frequency Module (위성통신 중간주파수 모듈용 국부발진기 누설제거에 관한 연구)

  • 서철헌;김영완;김내수;강민수
    • The Journal of Korean Institute of Communications and Information Sciences
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    • v.26 no.4B
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    • pp.400-405
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    • 2001
  • 본 논문에서는 Local Oscillator(LO)의 누설신호 제거를 위해 혼합기의 특성을 이용하여 광대역의 특성을 가지고 RF 채널에 근접한 누설신호를 제거할수 있는 구조를 제안하였다. 제안된 구조는 Half-LO 주파수를 이용하는 방버븡로 LO 누설신호를 일반적인 다른 경우보다 RF 신호대역에서 멀리 떨어진 대역으로 분리시킴으로서 대역 통과여파기로서 쉽게 제거하였다. 상향변환기로서 필요한 저역통과여파기, 대역통과여파기, 그리고 증폭기를 설계하였고 혼합기에 의한 영상성분은 혼합기의 위상을 특성을 이용하여 제거하였다.

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A fully integrated downconverter MMIC for millimeter wave applications (밀리미터파 응용을 위한 완전집적 다운컨버터 MMIC)

  • Jeon, Jang-Hyeon;Yun, Young
    • Journal of Advanced Marine Engineering and Technology
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    • v.37 no.1
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    • pp.99-104
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    • 2013
  • In this paper, we developed a fully integrated downconverter MMIC (monolithic microwave integrated circuit) including Lange coupler and output active balun for millimeter wave applications. Concretely, ${\lambda}$/4 transmission line was added to Lange coupler for size reduction of RF/LO input, and mixed RF/LO signals were applied to gate of the FET of mixer. Active balun was used at output port for a coupling of out-of-phase IF output signals. According to measured results, the proposed downconverter MMIC showed good RF performances. For example, the downconverter MMIC showed an LO leakage power of -25 dBc at IF output port, and a RF-LO isolation of 18 dB. Therefore, off-chip components such as LO rejection filters were not required for a normal operation of the proposed downconverter MMIC. The proposed downconverter MMIC showed a conversion gain of 10.3 dB at RF frequency of 63 GHz. The size of the downconverter MMIC including all active and passive components was $2.2{\times}1.4mm^2$.

A Design of Industrial Safety Service using LoRa Gateway Networks (LoRa 게이트웨이 네트워크를 활용한 산업안전서비스 설계)

  • Chang, Moon-soo
    • Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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    • 2021.10a
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    • pp.313-316
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    • 2021
  • In the IoT(IoT: Internet of Things) environment, network configuration is essential to collect data generated from objects. Various communication methods are used to process data of objects, and wireless communication methods such as Bluetooth and WiFi are mainly used. In order to collect data of objects, a communication module must be installed to collect data generated from sensors or edge devices in real time. And in order to deliver data to the database, a software architecture must be configured. Data generated from objects can be stored and managed in a database in real time, and data necessary for industrial safety can be extracted and utilized for industrial safety service applications. In this paper, a network environment was constructed using a LoRa(LoRa: Long Range) gateway to collect object data, and a client/server data collection model was designed to collect object data transmitted from the LoRa module. In order to secure the resources necessary for data collection and storage management without data leakage, data collection should be possible in real time. As an application service, location data required for industrial safety can be stored and managed in a database in real time.

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EFFECT OF CANAL TAPERING IN TEETH OF VARIOUS APICAL SIZE & CROSS-SECTIONAL CONFIGURATION ON MICROLEAKAGE (다양한 치근단공 크기와 근관단면의 형태를 가지는 치아에서 taper의 정도가 미세누출에 미치는 영향)

  • Kim, Jung-Hee;Lee, Kyung-Ha;Lee, Se-Joon;Yu, Mi-Kyung;Lee, Kwang-Won
    • Restorative Dentistry and Endodontics
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    • v.30 no.2
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    • pp.95-101
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    • 2005
  • The aim of this study was to evaluate the microleakage of teeth according to root canal preparation with & without apical enlargement in various size of apical foramen. 60 extracted one canal roots were cross-cutted at 5 mm from root apex and divided into two groups according to their apical foramen size of large (L) and small (S). Each group was subdivided into two groups accordance with their cross-sectional configuration at 5 mm from apex, round (R) and ovoid (O); SR Group, SO Group LR Group, LO Group. Each group was shaped in .02 taper by Quantec series Nickel-Titanium (NiTi) rotary file, obturated by lateral condensation method. Leakage was measured using a fluid transport model under 40 $cmH_2O$ pressure. After the leakage test, blocks which had showed the leakage retreated with .04 taper and ,06 taper and evaluated the degree of fluid filtration in each group. The data was analysed statistically using chi-square test and fisher's exact test. The results obtained were as follows : 1. Significant difference in leakage was found in groups which had different apical foramen size in .02 taper instrumentation (p < 0.05), but not in .04 taper instrumentation (p > 0.05) 2. The difference in microleakage according to the shape of canal was not evident at 5 mm from apex (p > 0.05). 3. There was correlation between .02 taper instrumentation and .04 taper instrumentation in LR group, LO group (p < 0.05).

Studies on IF noise caused by transmitter signal leakages of the W-band homodyne FMCW radar with a single antenna configuration (단일 안테나를 사용하는 W-대역 호모다인 FMCW 레이더의 누설신호에 의한 IF 잡음에 관한 연구)

  • Park Jung-Dong;Kim Wan-Joo
    • Journal of the Institute of Electronics Engineers of Korea TC
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    • v.42 no.7 s.337
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    • pp.49-56
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    • 2005
  • In this paper, we describe a solution to improve the effects of the transmitter leakage signals on the frequency modulated continuous wave (FMCW) radar with a single antenna configuration. We analyze characteristics of the IF noise caused by insufficient isolation between transmitter and receiver. The magnitude of the intermediate frequency (IF) noise from a front-end can be reduced by matching the LO signal delay time with that of the largest leakage source. Because the IF noise has periodic singularities at nT$_{m}$/2, t=0,1,2$\cdots$, we find that spectrum of the IF noise due to the leakage signals is very similar to that of the VCO moduation signal except low frequency elements in the vicinity of DC. Based on the studies, we fabricated a W-band homodyne FMCW radar sensor and verified the proposed solution. The results are applicable to design of the homodyne FMCW radar with a single antenna configuration.

Dual-Band Balanced Mixer using Nonlinear Phase Characteristic of CRLH Transmission Line (CRLH 전송선로의 비선형 위상 특성을 이용한 이중대역 평형 믹서)

  • Jung, Youn-Woo;Kim, Young;Yoon, Young-Chul
    • Journal of Advanced Navigation Technology
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    • v.15 no.1
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    • pp.97-103
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    • 2011
  • This paper presents a dual-band balanced mixer using nonlinear phase characteristic of composite right/left-handed (CRLH) transmission line. This metamaterial structure provides low LO leakage and high RF to LO isolation without additional filters for LO and RF path. The balanced mixer consists of balun and Wilkinson divider with dual-band characteristic of unit-cell which behaves like a CRLH metamaterial. Experimental results are used to verify the proposed metamaterial functions. The balanced mixer design results in an operating frequency of 870 MHz and 1660 MHz with an optimum mixer conversion loss of 15.2 dB at 870 MHz and 21.2 dB at 1660 MHz.