• Title/Summary/Keyword: 수신이득

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A Compensation Technique for Dispersive and Resonant Wideband Antenna using Stable Minimum-Phase ARMA System Modeling for Coherent Impulse Communication Systems (안정성을 갖는 최소 위상 ARMA 시스템 모델링을 이용한 코히어런트 임펄스 통신 시스템의 광대역 안테나 확산 및 공진 특성 보상 기법)

  • Lee Won-Cheol;Park Woon-Yong
    • The Journal of Korean Institute of Electromagnetic Engineering and Science
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    • v.15 no.10 s.89
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    • pp.983-995
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    • 2004
  • This paper introduces a pre-compensation filter for compensating dispersive and resonant properties experienced along the usage of non-ideal wideband antennas in impulse communication systems. It has been well blown that the transmitted impulse signal becomes deformed because of dispersive and resonant characteristics. Accordingly, in spite of using ideal template signal at the correlator in coherent receiver, these impairments degrade overall performance attributed to low level of coherence. To overcome this problem this paper exploits a realization technique of pre-compensation filter purposely installed at transmitter whose stability is automatically guaranteed because it has an inversion form of minimum-phase ARMA (Auto-Regressive Moving Average) system. The performance of proposed scheme will be shown in results from computer simulations to verify its affirmative impact on impulse communication system with regarding several distinctively shaped antennas.

MRC Diversity Reception Performance of DS/MPSK signal in Interference and m-distribution fading Environments (m-분포 페이딩과 간섭의 영향을 받는 DS/MPSK신호의 MRC 다이버시티 수신특성)

  • 강희조;고영혁;조성준
    • The Proceeding of the Korean Institute of Electromagnetic Engineering and Science
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    • v.6 no.3
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    • pp.55-67
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    • 1995
  • The error rate equations of MPSK and DS/MPSK radio signals transmitted through the m-distributed fading channel in Gaussian noise and tone interference environments have been derived. Using the derived equations, the error rate performance is evaluated and shown as functions of carrier-to-noise ratio, carrier-to-interference ratio, processing gain, fading index and the number of diversity branches. The derivation has been done for two cases. The first case assumes that only the signal is undergoing the influence of fading, and the second case assumes that both signal and interference are undergoing the influence of fading simultaneously. From the obtained results, we have known that the error performance of MPSK signal is improved by using diversity technique and direct sequence spread spectrum technique even in a fading environment. Also comparing the error rate performance of two cases, the latter is worse than the former.

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Design of a Dual-Frequency Microstrip Patch Antenna (이중 공진형 마이크로스트립 패치 안테나 설계)

  • 김규성;김태우;최재훈
    • The Journal of Korean Institute of Electromagnetic Engineering and Science
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    • v.10 no.7
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    • pp.1131-1137
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    • 1999
  • In this paper, a novel design method of an apertured coupled microstrip patch antenna with the single feeding structure is proposed for dual resonance frequencies with mutually perpendicular polarizations. The characteristics of this antenna are experimentally investigated. In order to achieve this goal, a new type of square patch with double notches is used as a radiator and the crossed slot and the bended mictrostrip feeder are adopted for the dual polarizations in the aperture-coupled structure. For the application of the proposed antenna, a Ku-band Tx/Rx $2\times$ subarray antenna is designed and manufactured. Also, the applicability of the antenna as a ground terminal is examined through performance analysis. According to the measurement, the gain of the antenna is 10dBi at the center frequencies of Tx and Rx, the side lobe level is lower than -13dB, and the cross polarization lebel is below 17 dB.

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Manufacture of a single gate MESFET mixer at PCS frequency band (PCS 주파수 대역 단일 게이트 MESFET 혼합기의 제작)

  • 이성용;임인성;한상철;류정기;오승엽
    • The Journal of Korean Institute of Electromagnetic Engineering and Science
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    • v.9 no.1
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    • pp.25-33
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    • 1998
  • In this paper, we describe a single-gate MESFET mixer at PCS(Personal Communication Service) frequency band. The PCS frequency band is 1965~2025 MHz in FR and 140 MHz in IF irrespectly. The design of the mixer was executed by microwave simulator, EEsof Libra. The matching network is consisted of rectangular inductor, MIM capacitor and open stub. The ma- nufacture work was accomplished by the micro-pen and wedge-bonder. The mixer showed $6.69\pm0.65$ dB of conversion gain, $-14.9\pm3.5$dB of RF reflection coefficient and 57.83 dB of LO/IF isolation at 10 dBm of LO power when LO frequency is 1855 MHz. When this mixer is used at PCS terminal, IF-amplifier which compensates the conversion loss of diode mixer may be omitted.

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Design and Measurement of Active Phased Array Radar Digital Receiver (능동 위상 배열 레이더의 디지털 수신기 제작 및 측정)

  • Kim, Tae-Hwan;Lee, Sung-Ju;Lee, Dong-Hwi;Hong, Yun-Seok;Cho, Choon-Sik
    • The Journal of Korean Institute of Electromagnetic Engineering and Science
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    • v.22 no.3
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    • pp.371-379
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    • 2011
  • Active phased array antenna structure is used for modern multi-function radars. To search targets in high clutter environment, the radar receiver needs high dynamic range performance. Though active phased array antenna structure lead to increase of SNR, the SFDR is not increased. In this paper, high SFDR receiver of X-band active phased array radar was designed and manufactured. One channel digital receiver is connected to 32 T/R modules and one PCB assembly is composed to 2 channel digital receivers with RF part, ADC part, LO distribution part and digital down conversion part. A commercial FIFO board was used for digital receiver measurement about major performance in digital output signal condition. The measured digital receiver gain and SFDR is 33 dB and more than 81 dBc each.

A CPW-Fed Ultra-Wideband Planar Monopole Antenna for UHF Band Applications (UHF 대역용 CPW 급전 초광대역 평면형 모노폴 안테나)

  • Yoo, Tae-Hoon;Kim, Tae-Hyung
    • The Journal of Korean Institute of Electromagnetic Engineering and Science
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    • v.23 no.7
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    • pp.761-767
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    • 2012
  • In this paper, a novel ultra-wideband planar monopole antenna for the UHF communications and Digital-TV reception is proposed. The proposed antenna fed by a coplanar waveguide(CPW) is based on a triangular patch that has a broadband characteristic. To further increase the bandwidth of the triangular patch antenna, the top side of the regular triangular patch is loaded with a notch cut and each oblique side with a step. In addition, a slope is given to the ground plane of the CPW structure. Experimental results show that the -10 dB return loss bandwidth of the proposed antenna is 2,320 MHz from 480~2,800 MHz(5.83:1 bandwidth), which covers all the frequency bands of the various wireless communication systems and Digital TV broadcasting in the UHF band. Within the entire operating frequency range, the measured antenna gain in y-z plane(E-plane) varies from 3.01 to 4.71 dBi.

An Interference Coordination Technique Utilizing Sub-Arrays and Its Performance in Cellular Systems (부 어레이 빔포밍을 활용하는 간섭 제어 기법 및 셀룰러 시스템에서의 성능 평가)

  • Kang, Hosik;Lee, Donghyun;Sung, Wonjin
    • The Journal of Korean Institute of Electromagnetic Engineering and Science
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    • v.25 no.6
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    • pp.653-663
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    • 2014
  • To cope with an increasing amount of data traffic, research efforts are being made to maximize the data rate by reducing the interference between the transmission nodes. This paper also focuses on interference control schemes utilizing antenna sub-array beam-forming. The first scheme relies on horizontal beam rotation which utilizes three types of narrow beam patterns. Different beam patterns are applied to transmit signals in rotating fashion to control the interference. The second scheme is based on user-specific sub-array beamforming, which uses the precoding matrix based on users' location and controls the amount of interference in the multi-user environment. The performance of the proposed schemes is evaluated using the computer simulation to demonstrate the performance enhancement.

A De-interleaving Method of Frequency Agility Radar Signals in Comparison with PRI's of radars (PRI 비교를 통한 주파수 급속변경 레이더 신호분리)

  • Lim, Joong-Soo;Hong, Kyung-Ho;Lee, Du-Kyung;Shin, Dong-Hoon;Kim, Yong-Hwan
    • Journal of the Korea Academia-Industrial cooperation Society
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    • v.10 no.8
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    • pp.1832-1838
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    • 2009
  • In this paper, we present new signal de-interleaving method for the frequency agility radar in which the carrier frequency is changed irregularly. Generally radar use a fixed carrier frequency, and it is easy for electronic warfare system to de-interleave the radar signal with respect to the frequency, pulse width(PW), and direction of signal arriving(DOA). In frequency agility radar, it is difficult to de-interleave the radar signals according to the carrier frequency because the frequency is changed irregularly. We suggest a good de-interleaving method to identify the frequency agility radar signals in comparison with PRI's of radars. First we calculate pulse repeat Interval(PRI) of radar in linked-list and queue structure and de-interleave the radar signals with PRI, PW, and DOA, then identify the frequency agility radar. When we use the proposed algorism to the frequency agility radar, we have a good de-interleaving results with electronic warfare systems.

A NEW ADAPTIVE BEAM-FORMING ALGORITHM BASED ON GENERALIZED ON-OFF METHOD FOR SMART ANTENNA SYSTEM (스마트 안테나 시스템을 위한 일반화된 ON-OFF방식의 새로운 적응 빔형성 알고리즘)

  • 이정자;안성수;최승원
    • The Journal of Korean Institute of Communications and Information Sciences
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    • v.28 no.10C
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    • pp.984-994
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    • 2003
  • This paper proposes a novel blind adaptive algorithm for computing the weight vector of an antenna array system. The new technique utilizes a Generalized On-Off algorithm to obtain the weight vector maximizing the SINR(Signal to Interference plus Noise Ratio) of the received signal. It is observed that the proposed algorithm generates a suboptimal weight vector with a linear computational load(O(6N+8)). From the various simulations, it is confirmed that, when the signal environment becomes adverse, e.g., low Processing Gain, and/or wide angular spread. the proposed algorithm outperforms the conventional one in terms of the communication capacity by about 3 times. Applying the proposed algorithm to satellite tracking systems as well as IS2000 1X mobile communication system, we have found that both communication capacity and communication quality are significantly improved.

A Study on the OFDM System Using Multi-Block SDM (Multi-Block SDM을 이용한 OFDM 시스템에 관한 연구)

  • Lee, Kyu-Jin;Kim, Ji-Sung;Kim, Nam-Il;Lee, Kye-San
    • The Journal of The Korea Institute of Intelligent Transport Systems
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    • v.7 no.5
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    • pp.122-130
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    • 2008
  • Improving the transmission rates of multi-media delivery, such as moving pictures and internet services, has become increasingly important in modern society. To satisfy such high data rate requirements, the MIMO technique, which has the capacity to transmit large amounts of data using limited frequency resources, was developed. The Space Division Multiplexing (SDM) system is one of the MIMO techniques to be able to improve the transmission capacity. However, it is unable to achieve diversity gain because of interference due to the use of multiple antennas. In this paper, an SDM system that utilizes a Multi-Block method as an advanced transmission technique in a wireless communication system to obtain diversity gain is proposed and discussed fur the performance of the proposed system.

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