• Title/Summary/Keyword: Antenna Efficiency

Search Result 537, Processing Time 0.03 seconds

Energy-Efficient Antenna Selection in Green MIMO Relaying Communication Systems

  • Qian, Kun;Wang, Wen-Qin
    • Journal of Communications and Networks
    • /
    • v.18 no.3
    • /
    • pp.320-326
    • /
    • 2016
  • In existing literature on multiple-input multiple-output (MIMO) relaying communication systems, antenna selection is often implemented by maximizing the channel capacity or the output single-to-noise ratio (SNR). In this paper, we propose an energy-efficient low-complexity antenna selection scheme for MIMO relaying communication systems. The proposed algorithm is based on beamforming and maximizing the Frobenius norm to jointly optimize the transmit power, number of active antennas, and antenna subsets at the source, relaying and destination. We maximize the energy efficiency between the link of source to relay and the link of relay to destination to obtain the maximum energy efficiency of the system, subject to the SNR constraint. Compared to existing antenna selection methods forMIMO relaying communication systems, simulation results demonstrate that the proposed method can save more power in term of energy efficiency, while having lower computational complexity.

Antenna Efficiency Variation by the Influence of Human Body (인체의 영향에 의한 안테나 효율의 변화)

  • Lee, Yong-Joo;Han, Jun-Hee;Yang, Woon-Geun
    • Journal of IKEEE
    • /
    • v.12 no.4
    • /
    • pp.185-195
    • /
    • 2008
  • In this paper, PIFA(Planar Inverted F Antenna) which operates in PCS(Personal Communication System) band is designed and characteristics are investigated. Designed PIFA was installed in three types of handsets, folder, bar, slide, and the performance was evaluated. Head and hand phantom were added to make the most similar environment to real condition of mobile phone use, and influences on antenna performance were analyzed. The simulation results confirm radiation patterns are greatly changed and antenna efficiency is decreased by the effect of human body. Performance variation of the mobile handset antenna was observed as changing the angle between mobile handset and head phantom from $0^{\circ}$ to $2^{\circ},\;4^{\circ}$ to confirm the variation caused by the relative position of mobile handset and head phantom. Directivity was decreased gradually as the antenna goes away from head phantom, and showed the trend of increasing efficiency. But in the case of bar type, where the position of antenna is relatively close to head phantom, that trend didn't show. It was confirmed that the shape of handset has a great effect on the performance.

  • PDF

Effects of ground size on characteristics of ENG ZOR antennas (접지면 크기가 ENG ZOR 안테나 특성에 미치는 영향)

  • Lee, Seung-Wook;Park, Jae-Hyun;Lee, Jeong-Hae
    • Journal of the Institute of Electronics Engineers of Korea TC
    • /
    • v.45 no.8
    • /
    • pp.8-14
    • /
    • 2008
  • In this paper, the effects of ground size on the characteristics such as input resistance, fractional bandwidth, and radiation efficiency of epsilon negative (ENG) zeroth order resonance (ZOR) antennas were investigated theoratically. Two types of ENG ZOR antennas were studied: mushroom ENG ZOR antenna with via and via-free defected ground structure (DGS) ENG ZOR antenna. It was confirmed that the ground size had more effects on the characteristics of a Via-free ZOR antenna than those of mushroom ZOR antenna with via. The via-free antenna could radiate properly with the required size of ground plane since the size of ground plane should exceed some critical value for DGS to suitably operate. As a height of substrate of mushroom ZOR antenna with via increased, the fractional bandwidth and radiation efficiency were improved. On the other hand, as a height of via-free ZOR antenna increased, the fractional bandwidth and radiation efficiency were degraded. Finally, a via-free ZOR antenna had an advantage of compactness even though its fractional bandwidth is narrow and its radiation efficiency is poor, compared with thoses of mushroom ZOR antenna with via.

Analysis of High Efficiency Small Antenna with Matching Circuit (정합회로 장착 고효율 소형안테나의 해석)

  • Hwang, Jae-Ho
    • Journal of the Korea Institute of Information and Communication Engineering
    • /
    • v.16 no.7
    • /
    • pp.1358-1363
    • /
    • 2012
  • This paper deals with the analysis of high efficiency small antenna like superconductor antenna. The superconductor antenna is useful to low frequency range because surface resistance of superconductor increased with the rate of square of frequency. Thus, the used antenna increases in size. For such a reason, the role of the matching circuit is very important in small antenna. In this paper, low loss antenna included the optimal structure of matching circuit is analyzed by using quasi-static approximation. To verify the results of this paper, input impedance and radiation characteristics of this antenna have been evaluated.

Method to Obtain the Antenna Efficiency of a Base Station in the Middle Frequency Band (중파 대역 기준국 안테나의 효율 측정 방법)

  • Bae, Su-Won;Kwon, Se-Woong;Lee, Woo-Sung;Moon, Hyun-Wook;Yoon, Young-Joong
    • The Journal of Korean Institute of Electromagnetic Engineering and Science
    • /
    • v.19 no.5
    • /
    • pp.572-579
    • /
    • 2008
  • To predict the system coverage in the middle frequency(MF) band, it is required to know the antenna efficiency at a base station. However, calculating the accurate efficiency is difficult since the efficiency may change according to the area where the antenna is installed. Thus, this paper proposes a method to obtain the antenna efficiency of a base station in the MF band from the measurement. This method uses the measured field strengths and the attenuation model in the MF band. Therefore, an attenuation model which is used in the proposed method is presented at first. Then, the process of the proposed method is followed using detailed explanations. Finally, antenna efficiencies of base stations which are currently operating are obtained by applying the proposed method and the usefulness of the obtained results are verified by comparing with ideal efficiencies.

Design and Characterization for High-Tc Superconducting Microstrip Patch Antenna (고온초전도 마이크로스트립 패치 안테나의 설계 및 특성 해석)

  • Jeong, Dong-Cheol;Choe, Myeong-Ho;Gang, Hyeong-Gon;Im, Seong-Hun;Han, Byeong-Seong
    • The Transactions of the Korean Institute of Electrical Engineers C
    • /
    • v.49 no.4
    • /
    • pp.219-225
    • /
    • 2000
  • In this paper, we report the experimental setup and characterization of experimental results for the HTS antenna. The constructions of experimental setup must be fabricated, cautiously. We constructed the cryostat made of 3 stages which consists of radome, vacuum stage and helium refrigerator for the HTS antenna. The HTS antenna was mounted to cryostat and various characteristics were measured at room temperature and liquid nitrogen temperature, 77 K. Also the results for the HTS antenna and the gold antenna were compared in terms of reflection coefficient, E-plane and H-plane radiation pattern, input impedance, SWR and efficiency. It appeared that the HTS antenna was superior to gold counterpart over the all characteristics.

  • PDF

Analysis and fabrication of a wearable antenna using conductive fibers (전도성 실 재질을 이용한 웨어러블 안테나의 제작 및 분석)

  • Nguyen, Tien Manh;Chung, Jae-Young
    • Journal of the Korea Academia-Industrial cooperation Society
    • /
    • v.16 no.4
    • /
    • pp.2770-2776
    • /
    • 2015
  • The development of efficient wearable antennas is required to implement short range body-centric wireless communication links for various internet of thing applications. We present simulation and measurement results of conductive-fiber-based wearable antennas which can comfortably fabricated directly on usual clothing materials. The proposed antenna is a form of a rectangular patch antenna designed by weaving conductive fibers on a felt substrate. A full-wave electromagnetic simulation tool is used to investigate the antenna performance such as antenna impedance, resonant frequency, and radiation efficiency. Parametric studies show that the radiation efficiency increases from 67.5% to 70.4% by widening the gap between conductive fibers from 0.25mm to 3mm. This implies a wearable antenna with good radiation efficiency can be designed despite of less portion of conductive fibers on the antenna. The simulation results are also verified by measured results with fabricated antennas.

Energy-efficiency Optimization Schemes Based on SWIPT in Distributed Antenna Systems

  • Xu, Weiye;Chu, Junya;Yu, Xiangbin;Zhou, Huiyu
    • KSII Transactions on Internet and Information Systems (TIIS)
    • /
    • v.15 no.2
    • /
    • pp.673-694
    • /
    • 2021
  • In this paper, we intend to study the energy efficiency (EE) optimization for a simultaneous wireless information and power transfer (SWIPT)-based distributed antenna system (DAS). Firstly, a DAS-SWIPT model is formulated, whose goal is to maximize the EE of the system. Next, we propose an optimal resource allocation method by means of the Karush-Kuhn-Tucker condition as well as an ergodic method. Considering the complexity of the ergodic method, a suboptimal scheme with lower complexity is proposed by using an antenna selection scheme. Numerical results illustrate that our suboptimal method is able to achieve satisfactory performance of EE similar to an optimal one while reducing the calculation complexity.

Resistive and Inductive Loading Techniques on Microstrip Antenna for Wideband Application

  • Jeon, Sang-Bong;Ahn, Chang-Hoi
    • Journal of Electrical Engineering and Technology
    • /
    • v.6 no.5
    • /
    • pp.693-696
    • /
    • 2011
  • In this work, an exponentially tapered microstrip antenna was implemented using a resistive loading technique in order to suppress the internal reflections. The inductive loading was realized by introducing slits on the antenna to improve radiation efficiency. Compared with a resistive-loaded antenna, the proposed antenna had an average improvement of about 6.2% in radiation efficiency within the range of 2-10.5 GHz. In addition, the highest peak of the radiated short pulse from the proposed antenna became 45% greater than that of an antenna with resistive loading only.

Antenna Efficiency Measurement Using the Modified Wheeler Cap Method (개선된 Wheeler Cap 방식을 이용한 안테나 효율 측정)

  • Cho Chi-Hyun;Choo Ho-Sung;Park Ik-Mo;Kang Jin-Seob
    • The Journal of Korean Institute of Electromagnetic Engineering and Science
    • /
    • v.17 no.4 s.107
    • /
    • pp.317-323
    • /
    • 2006
  • The conventional Wheeler cap method can extract the reliable efficiency of the antenna when the antenna operates as a simple series or parallel RLC circuit model. This method, however, may give an unreliable efficiency when the antenna under test has a complicated operating principle. In this paper, we revisit the conventional Wheeler cap method and propose a modified Wheeler cap method basedon the high-order circuit model. The proposed method can provide an accurate efficiency even for the antenna with a more complicated operating principle. Then we calculate efficiencies of other antennas with different operating principles and compare the results with the simulations.