Nai-Chang Yuan

National University of Defense Technology, Changsha, Hunan, China

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Publications (18)12.15 Total impact

  • Hui Zhang, You-Quan Li, Xi Chen, Yun-Qi Fu, Nai-Chang Yuan
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    ABSTRACT: A novel kind of circular polarization and dual-frequency linear polarization microstrip antennas is proposed. The designs are based on the anisotropic property of the complementary split ring resonator. When the complementary split ring resonator is etched on the patch of the probe-fed microstrip antenna, the gap orientation asymmetric or symmetric to the current propagating direction will render the antenna to radiate circular polarization waves or dual-frequency linear polarization waves. Details of the experimental results compared with the simulated results are presented and discussed.
    IEEE Transactions on Antennas and Propagation 11/2009; · 2.33 Impact Factor
  • Qiu-Rong Zheng, Yun-Qi Fu, Nai-Chang Yuan
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    ABSTRACT: A novel compact electromagnetic band-gap (EBG) structure in a spiral shape is presented and investigated. This structure significantly enlarges the capacitance between neighboring elements. The simulations and experimental results have proved that the size of the spiral structure is only 30.9% of the conventional EBG structure. Two applications have been shown, including patch antenna with the spiral EBG structure and a double-element microstrip antenna array with low mutual coupling. The measured results show that a gain improvement over 3 dB and a significant reduction of cross polarization in H-plane are obtained. A 6 dB reduction of mutual coupling is achieved in a double-element EBG microstrip antenna array.
    IEEE Transactions on Antennas and Propagation 07/2008; · 2.33 Impact Factor
  • You-Quan Li, Hui Zhang, Yun-Qi Fu, Nai-Chang Yuan
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    ABSTRACT: This letter investigates the application of EBG radar absorbing material (RAM) to asymmetric ridged waveguide slot antenna array to reduce its backward RCS. The EBG RAM is based on the mushroom-like EBG structure loaded with lumped resistances. A ridged waveguide slot antenna array with 4 times 10 slot elements was designed and built, part of the metal ground plane of the array is replaced with this EBG RAM. The measured results show that performance of the antenna array is preserved when EBG RAM is used. At working frequency the backward RCS of antenna array with EBG RAM has dramatically reduced than that of the common antenna array.
    IEEE Antennas and Wireless Propagation Letters 02/2008; · 1.67 Impact Factor
  • Source
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    ABSTRACT: In this paper a novel ultra-thin radar absorbent material (RAM) using HIGP is presented and investigated. Owing to the high impedance property of the HIGP, the thickness of the RAM is about several tenths of the centre wavelengthof the absorption band, considerably thinner than conventional absorbers. The absorption band of the RAM is about several hundred megahertz. In the new RAM, lumped resistances are soldered between the patches of mushroom-like high-impedance surface (HIGP). And the metal ground plane of waveguide slot antenna is covered by this new type of RAM. As compared to the slot antenna with a metal ground plane, the measured results show that the radar cross section (RCS) of waveguide slot antenna reduces significantly. This proves that the new HIGP RAM has a good radar absorbing characteristics. The simulations and experiment results have shown that the RCS of antenna is reduced by 7.9 dB and gain is only reduced by 0.9 dB.
    Progress in Electromagnetics Research-pier - PROG ELECTROMAGN RES. 01/2008;
  • Hui Zhang, You-Quan Li, Xi Chen, Yun-Qi Fu, Nai-Chang Yuan
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    ABSTRACT: A novel design of circular polarization microstrip patch antenna based on the complementary split ring resonator is evaluated numerically and experimentally verified. Unlike the previous application of its resonant performance, the non-resonant property of complementary split ring resonator is used as an asymmetric perturbation to excite the square microstrip patch antenna for a good circular polarization radiation. Good agreement is observed between the measurement and simulation results.
    01/2008;
  • Bao-Qin Lin, Qiu-Rong Zheng, Nai-Chang Yuan
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    ABSTRACT: A novel electromagnetic Band-Gap (EBG) scheme is presented for size reduction. The proposed structure can be considered as one kind of distorted Sievenpiper High Impedance Surface (HIS) in a spiral shape, while it becomes extremely compact in size. Its design is detailed in this study, and two experimental results are presented. © 2007 Wiley Periodicals, Inc. Microwave Opt Technol Lett 49: 2186–2189, 2007; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.22691
    Microwave and Optical Technology Letters 06/2007; 49(9):2186 - 2189. · 0.59 Impact Factor
  • Bo Lv, Rui-Hai Liang, Xiao-Fa Zhang, Nai-Chang Yuan
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    ABSTRACT: First introduced the theory of PLL, analyzed the factors in the multi-PLL system that may affect the isolation. Then employing EMC theory analyzed and designed the multi-PLL system. At the end, presented the results of isolation measurements. The methods used in the design are especially useful and helpful for the design of multi-channel receiver.
    Antennas, Propagation & EM Theory, 2006. ISAPE '06. 7th International Symposium on; 11/2006
  • Feng-tao Wu, Nai-chang Yuan
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    ABSTRACT: Finite-difference time-domain (FDTD) algorithm was used to analyze ultra-wide-band (UWB) antenna array. Normalized radiation energy pattern was adopted to characterize the transmitting and receiving behaviour of (UWB) antenna array. Measured and simulated results indicate the planar TEM horn antenna array can be used in the practical UWB radar and communication system
    Radar, 2006. CIE '06. International Conference on; 11/2006
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    Bao-qin Lin, Qiu-rong Zheng, Nai-chang Yuan
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    ABSTRACT: A novel planar photonic band-gap (PBG) scheme is presented for size reduction, the proposed structure can be considered as a kind of distorted uniplanar compact-PBG (DUC-PBG) while being even more compact in size. Its design is detailed in this letter, and several experimental results are presented, the properties of the proposed DUC-PBG are examined, as compared with that of the conventional UC-PBG.
    IEEE Microwave and Wireless Components Letters 06/2006; · 1.78 Impact Factor
  • Qiu-Rong Zheng, Guo-hua Zhang, Nai-Chang Yuan
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    ABSTRACT: High impedance ground plane (HIGP) is a kind of electromagnetic band-gap (EBG) structure utilized as a ground plane for a single ridged wave-guide slot phased antenna array in order to improve its radiation characteristics. As compared to a solid metal ground plane, the results suggest that the HIGP can significantly improve the pattern of slot antenna array. The antenna gain is increased, the back lobes are reduced and the mutual coupling between two antenna arrays is reduced.
    Microwave Conference Proceedings, 2005. APMC 2005. Asia-Pacific Conference Proceedings; 01/2006
  • Hui Zhang, Dun-bao Yan, Nai-Chang Yuan
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    ABSTRACT: A novel microstrip dipole antenna with H-shaped slot coupled is presented. Several design variations are discussed. Compared to the traditional microstrip dipoles with rectangular coupling slot, this antenna which occupies smaller volume is more suitable to be integrated with other microstrip antenna or active devices.
    Microwave Conference Proceedings, 2005. APMC 2005. Asia-Pacific Conference Proceedings; 01/2006
  • Bo Lv, Xiao-Fa Zhang, Nai-Chang Yuan
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    ABSTRACT: In this paper, design theory for the X-band power amplifier is introduced firstly, and CAD method is used to design the bias circuit. Precautions In the installation of GaAs FET are given. Power supply protection circuit is designed to satisfy the turn-on and turn-off sequences. At the end test results are presented
    01/2006;
  • Qiang Gao, Guo-hua Zhang, Dun-bao Yan, Nai-chang Yuan
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    ABSTRACT: High-impedance surface (HIS) is a kind of electromagnetic bandgap (EBG) structure utilized as a ground plane for two waveguide slot antennas in order to improve their radiation characteristics. As compared to a solid metal ground plane, the results suggest that a high-impedance ground plane (HIGP) can significantly improve the patterns of the slot antennas. The ripples in the E-plane patterns of the slot antennas with a metal ground plane are found to vanish, the back lobes are reduced, and the gains are increased.
    01/2005;
  • Dun-bao Yan, Qiang Gao, Chao Wang, Nai-chang Yuan
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    ABSTRACT: In this paper, the patch size effect of mushroom-like Sievenpiper AMC (Artificial Magnetic Conductor) structure to reflection phase band-gap is studied. It is observed that the reflection phase band-gap is independent of the size in the direction perpendicular to polarization direction of incident plane wave. Consequently, strip- type AMC structure is introduced, and it is noticed this structure has independent reflection phase property and surface wave band-gap property. Compared with mushroom-like Sievenpiper structure, strip-type AMC structure is easier to design and fabrication, and has many advantages in antenna applications to circular patch antenna, plane spiral antenna and corrugated horn antenna etc.
    PIERS Online 01/2005; 1(5):505-509.
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    Dun-bao Yan, Chao Wang, Qiang Gao, Nai-chang Yuan
    PIERS Online 01/2005; 1(6):695-698.
  • Qiu-Rong Zheng, Yun-qi Fu, Nai-Chang Yuan
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    ABSTRACT: A high impedance ground plane (HIGP) structure is used for asymmetric single ridged wave-guide slot antenna. As compared to a solid metal ground plane, the measured results proved that HIGP can significantly improve the radiation pattern. The radiation pattern become smoothly, the back lobe reduced and the gain is increased.
    01/2005;
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    ABSTRACT: A high-impedance ground plane (HIGP) is used for a circular waveguide antenna. The benefits of using such a HIGP are related to the suppression of surface waves excited by the circular waveguide mouth, because the HIGP has a very obvious surface wave bandgap. Suppression or reduction of surface waves is expected to improve antenna efficiency and to bring a reduction of sidelobe level due to diffraction of the surface waves. In agreement with the expected result, the measured radiation patterns show that a 2 dB addition in the antenna gain and a 10 dB reduction in the back lobes, if the circular waveguide antenna working frequency is in the HIGP surface wave bandgap.
    IEEE Antennas and Wireless Propagation Letters 02/2003; · 1.67 Impact Factor
  • Yun-Qi Fu, Guo-Hua Zhang, Nai-Chang Yuan
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    ABSTRACT: A novel coplanar waveguide with photonic bandgap structure is proposed and is implemented by etching holes in the ground plane with an open connected with the gap between strip line and ground plane. Simulation and measurement results show the existence of a bandgap.
    IEEE Microwave and Wireless Components Letters 12/2001; · 1.78 Impact Factor