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Yang-Xiao Qi

Bio: Yang-Xiao Qi is an academic researcher from Northwestern Polytechnical University. The author has contributed to research in topics: Antenna (radio) & Microstrip antenna. The author has an hindex of 6, co-authored 15 publications receiving 221 citations.

Papers
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Journal ArticleDOI
TL;DR: In this paper, a dual circularly polarized (CP) antenna with an U-shaped slot and two 50-Omega $ microstrip-fed ports was proposed to realize both right-hand circular polarization and left-hand polarization at the same frequency band.
Abstract: In this communication, a novel broadband dual circularly polarized (CP) antenna is presented. This antenna consists of an U-shaped slot to achieve broadband CP radiation and two 50- $\Omega $ microstrip-fed ports to realize both right-hand circular polarization and left-hand circular polarization at the same frequency band. The axial ratio bandwidth (ARBW) is greatly broadened by moving the feeding ports to upper portion of the U-shaped slot. To verify this design, the proposed antenna is fabricated and measured. The measured −10 dB reflection coefficient bandwidth is about 114.4% (1.80–6.61 GHz) and the 3-dB ARBW is approximately 110.5% (1.83–6.35 GHz). The isolation between two ports is better than 14.8 dB within the ARBW.

81 citations

Journal ArticleDOI
TL;DR: In this article, a wide-beam microstrip antenna with metal walls is proposed to improve the wide-angle scanning performance of the phased array antennas, and the beamwidth of the antenna is broadened by the horizontal current on the radiating patch and the vertical currents on the metal walls.
Abstract: In order to improve the wide-angle scanning performance of the phased array antennas, a wide-beam microstrip antenna with metal walls is proposed in this letter. The beamwidth of the antenna is broadened by the horizontal current on the radiating patch and the vertical current on the metal walls. The half-power beamwidth of the E- and H-planes is 221° and 168° at 4.0 GHz. Furthermore, the wide-beam antenna element is employed in a nine-element E-plane linear array antenna. The main beam of the E-plane scanning linear array antenna can scan from −70° to +70° in the frequency band from 3.7 to 4.3 GHz with a gain fluctuation less than 2.7 dB and variation in maximum sidelobe level less than −5.8 dB. The E-plane scanning linear array antenna with nine elements is fabricated and tested. The measured results achieve a good agreement with the simulated results.

78 citations

Journal ArticleDOI
TL;DR: In this article, a microstrip-fed simple square slot antenna is proposed for triple-wideband triple-sense circularly polarized radiation, which consists of an L-shaped radiator and a frame lower ground structure with two rectangular strips at opposite corner.
Abstract: In this letter, a microstrip-fed simple square slot antenna is proposed for triple-wideband triple-sense circularly polarized radiation. It consists of an L-shaped radiator and a frame lower ground structure with two rectangular strips at opposite corner. A rectangular slit, which is cut on the right side rectangular strip at the lower ground, is mainly used to broaden axial-ratio bandwidth (ARBW) at upper band. This antenna radiates right-hand circularly polarized wave at lower and upper bands, and radiates left-hand circularly polarized wave at middle frequency band. The antenna has been fabricated and measured. Good agreement is achieved between the simulation and measurement. The measured impedance bandwidths are 44.0% (2.34–3.66 GHz) and 70.9% (4.55–9.55 GHz). The measured 3-dB ARBWs for the triple bands are 35.9% (2.40–3.45 GHz), 44.0% (4.65–7.27 GHz), and 6.3% (8.13–8.66 GHz), respectively. The measured peak gains within the 3-dB ARBWs are 4.2, 3.7, and 3.5 dBic, respectively.

58 citations

Journal ArticleDOI
TL;DR: In this paper, a technique for the synthesis of shaped beam radiation patterns is proposed based on superposition principle and Taylor method, which may control the sidelobe level of the shaped beam.
Abstract: A technique for the synthesis of shaped beam radiation patterns is proposed. The new synthesis method is based on superposition principle and Taylor method. The method may control the sidelobe level of the shaped beam. The approach includes four steps: 1) get the distribution of pencil beam array with low sidelobe by Taylor method; 2) let the beams scan as a phased array to the specific angles according to the requirement of the shaped beam, The sum pattern is close to the shaping beam; 3) determine the value of angles and weights; and 4) count the distribution of the shaped beam array according to the new array factor function. Numerical results are provided to assess the capabilities of the proposed design method. The method develops an effective approach for the synthesis of shaped beams via uniform linear arrays. Both the ripple and sidelobe level of shaped beam may be controlled by the new synthesis method.

57 citations

Journal ArticleDOI
TL;DR: In this paper, a high-impedance periodic structure (HIPS) was applied to improve the radiation pattern of the antenna element in an array, which could improve the surface wave and broad-beam radiation performance of individual antenna element as well as the wide scan performance of the phased array.
Abstract: In this letter, the performance of wide-angle scanning phased array is analyzed. A high-impedance periodic structure (HIPS) is applied to improve radiation pattern of the antenna element in an array. The working mechanism of HIPS array is investigated. The structure could improve the surface-wave and the broad-beam radiation performance of the individual antenna element as well as the wide scan performance of the phased array. By the comparison to the metal ground plane, the gain of the array antenna is improved approximately 4.5 dB when the main beam scans at ±60°. A nine-element array antenna with a periodic structure is fabricated and measured. The measured results of the array coincide with the simulated results.

54 citations


Cited by
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01 Jan 2016

733 citations

Journal ArticleDOI
TL;DR: A planar, low-profile, dual-band and dual-polarized antenna on a semi-flex substrate is proposed in this paper, which indicates the effectiveness of the AMC array in increasing gain and FBR, besides reducing EM absorption in the human body.
Abstract: A planar, low-profile, dual-band and dual-polarized antenna on a semi-flex substrate is proposed in this paper. The antenna is fabricated on Rogers substrate with a thickness of 3.04 mm and sized at $70.4 \times 76.14 \times 3.11$ mm3 ( $0.37\lambda _{0} \times 0.40\lambda _{0}\times 0.016 \lambda _{0}$ ) only. The circular polarization property is enabled in the global navigation satellite system (GNSS) L1/E1 (lower) band by introducing a complementary split ring resonator on the antenna patch. Meanwhile, the antenna operates in the second (upper) 2.45 GHz WLAN band is enabled by etching a U-shaped slot on its ground plane. This simultaneous, dual-band and dual-polarized operation enables the proposed antenna to be applied in the indoor/outdoor wearable application. To isolate the antenna against the influence of the human body, a multiband artificial magnetic conductor (AMC) plane is added on the reverse side of the dual-band radiator. Comparison of the antenna without AMC in free space and when evaluated on the chest of a human body backed by AMC showed improved gain; from 3–5.1 dBi in the lower band, and from 1.53–5.03 dBi in the upper band. Besides that, the front-to-back ratio of the AMC backed monopole antenna also improved from 11–21.88 dB and from 2.5–24.5 dB in the GNSS and WLAN bands, respectively. Next, the specific absorption rate (SAR) of the monopole antenna with and without the AMC plane is assessed. Evaluation results indicate that the maximum SAR value decreased by up to 89.45% in comparison with the antenna without AMC in the lower band. This indicates the effectiveness of the AMC array in increasing gain and FBR, besides reducing EM absorption in the human body.

89 citations

Journal ArticleDOI
TL;DR: In this article, a wide-beam microstrip antenna with metal walls is proposed to improve the wide-angle scanning performance of the phased array antennas, and the beamwidth of the antenna is broadened by the horizontal current on the radiating patch and the vertical currents on the metal walls.
Abstract: In order to improve the wide-angle scanning performance of the phased array antennas, a wide-beam microstrip antenna with metal walls is proposed in this letter. The beamwidth of the antenna is broadened by the horizontal current on the radiating patch and the vertical current on the metal walls. The half-power beamwidth of the E- and H-planes is 221° and 168° at 4.0 GHz. Furthermore, the wide-beam antenna element is employed in a nine-element E-plane linear array antenna. The main beam of the E-plane scanning linear array antenna can scan from −70° to +70° in the frequency band from 3.7 to 4.3 GHz with a gain fluctuation less than 2.7 dB and variation in maximum sidelobe level less than −5.8 dB. The E-plane scanning linear array antenna with nine elements is fabricated and tested. The measured results achieve a good agreement with the simulated results.

78 citations

Journal ArticleDOI
TL;DR: In this article, two wide-angle scanning linear array antennas (E- and H-planes scanning linear arrays antenna) are studied and presented, and a wide beamwidth U-shaped microstrip antenna with the electric walls is designed.
Abstract: Two wide-angle scanning linear array antennas (E- and H-planes scanning linear array antenna) are studied and presented. In order to improve the wide-angle scanning performance of the phased array antenna, a wide beamwidth U-shaped microstrip antenna with the electric walls is designed. The wide-angle scanning linear array antennas are studied in the frequency band from 3.2 to 3.8 GHz. The 3 dB beamwidth of the antenna is 140° in the E-plane scanning linear array center and 220° in the H-plane scanning linear array center at 3.5 GHz. The main beams of the H-plane scanning linear array antenna can scan from −90° to +90° with a gain fluctuation less than 3 dB and a maximum sidelobe level (SLL) less than −5 dB. Simultaneously, the main beam of the E-plane scanning linear array antenna can scan from −75° to +75° with a gain fluctuation less than 3 dB and SLL less than −5 dB. The H- and E-planes scanning linear array antennas with nine elements are fabricated and tested. The measured results have a good agreement with the simulation results.

73 citations

Journal ArticleDOI
TL;DR: In this paper, a wideband magnetoelectric (ME) dipole antenna with wide beamwidth both in the E-plane and H-plane is investigated, which is a differential one.
Abstract: In this paper, a wideband magnetoelectric (ME) dipole antenna with wide beamwidth both in the E-plane and H-plane is investigated The proposed antenna, which is a differential one, has a simple structure and can realize wide beamwidth in the E-plane and H-plane in whole operating bandwidth This antenna is easy to manufacture and low cost The antenna consists of a pair of $\Gamma$ -shaped metal plates, a $\Gamma$ -shaped fed line, and six metal columns The $\Gamma$ -shaped metal plates and metal columns change the current distribution which changes the radiation performance of the proposed antenna Some parameters, which effect on the performances of the antenna, are studied The proposed antenna achieves the impedance bandwidth (≤−10 dB) of about 811% (33–78 GHz) The half-power beamwidth (HPBW) of the proposed antenna is obviously broadened The HPBW is 215° in the E-plane and 186° in the H-plane at 55 GHz Besides, the cross polarization of the antenna is very low The antenna is fabricated and measured to verify the design The measured results are in good agreements with the simulated one Good radiation characteristics of the new ME dipole antenna have been obtained in the whole frequency band

70 citations