带有U型寄生单元的宽带微带贴片天线(有出处)--中英文翻译-2

外文翻译原文Wideband Microstrip Patch Antenna With U-Shaped Parasitic ElementsSang-Hyuk Wi, Yong-Shik Lee, and Jong-Gwan YookAbstractA wideband U-shaped parasitic patch antenna is proposed. Two parasitic elements are incorporated into the radiating edges of a rectangular patch whose length and width are /2 and/4, respectively, in order to achieve wide bandwidth with relatively small size. Coupling between the main patch and U-shaped parasitic patches is realized by either horizontal or vertical gaps. These gaps are found to be the main factors of the wideband impedance matching. The proposed antenna is designed and fabricated on a small size ground plane (25 mm30 mm) for application of compact transceivers. The fabricated antenna on a FR4 substrate shows an impedance bandwidth of 27.3% (1.5 GHz) at 5.5 GHz center frequency. The measured radiation patterns are similar to those of a conventional patch antenna with slightly higher gains of 6.4 dB and 5.2 dB at each resonant frequency.Index TermsParasitic patch antenna, U-shaped parasitic patches, wide bandwidth.I. INTRODUCTIONDemand for compact and multifunctional wireless communication systems has spurred the development of multiband and wideband antennas with small size. Microstrip patch antennas are widely used in this regard as they offer compactness, a low prole, light weight, and economical efciency. However, the microstrip patch antenna is limited by its narrow operating bandwidth.There are numerous and well-known methods to increase the bandwidth of antennas, including increase of the substrate thickness 1, the use of a low dielectric substrate 1, the use of various impedance matching and feeding techniques 2, the use of multiple resonators37, and the use of slot antenna geometry 8. However, the bandwidth and the size of an antenna are generally mutually conicting properties, that is, improvement of one of the characteristics normally results in degradation of the other.Recently, several techniques have been proposed to enhance the bandwidth. In 911, utilizing the shorting pins or shorting walls on the unequal arms of a U-shaped patch, U-slot patch, or L-probe feed patch antennas, wideband and dual-band impedance bandwidth have been achieved with electrically small size.In this work, a wideband microstrip patch antenna employing parasitic elements is investigated. Two U-shaped parasitic elements are incorporated along the radiating edges of a probe fed rectangular patch antenna so as to obtain wideband operating frequency. In addition, the antenna is relatively small in comparison with the conventional parasitic patch antenna described in 4, 5. Performance of the proposed antenna is calculated and measured. The proposed antenna geometry is described in Section II. The fabricated antenna and experimental validations are presented in Section III.Manuscript received August 2, 2006; revised October 11, 2006. This work was supported by the Ministry of Information and Communication (MIC), Korea, under the Information Technology Research Center (ITRC) support program supervised by the Institute of Information Technology Assessment (IITA-2005-C1090-0502-0012).The authors are with the Department of Electrical and Electronic Engineering, Yonsei University, Seoul 120-749, Korea (e-mail: wshnuryyonsei.ac.kr; jgyookyonsei.ac.kr).Digital Object Identier 10.1109/TAP.2007.893427II. ANTENNA DESIGNFig. 1 depicts the top and side views of the proposed antenna. The proposed antenna consists of a probe fed half-wavelength rectangular patch and two U-shaped parasitic elements incorporated around the radiating edges of the rectangular patch. In general, the length and width of the rectangular patch antenna are close to half-wavelength. However, the length (LR) and width (WR) of the main patch vary from the proposed design. In order to maintain the inherent resonant length with smaller size, WR is reduced to /2 and LR is defined as about /2, where is the guided wavelength. Probe feeding is accomplished by a vertical via hole through the substrate material. Fig. 1. Geometry of the proposed microstrip patch antenna with U-shaped parasitic elements. The proposed antenna has two parasitic elements to obtain wide impedance bandwidth. Using the geometrical feature of the U-shaped patch, the size of the antenna can be miniaturized. Notable, although two parasitic patches are positioned in the proximity of the radiating edges of the main patch, all of the radiating and nonradiating edges of the main patch are surrounded by U-shaped parasitic elements. Electromagnetic coupling between the main patch and parasitic patches is realized across either horizontal (GH) or vertical gaps (GV ). In addition, the resonant length of the U-shaped patches can be controlled by adjusting its length (LU) and width (WU).The proposed antenna is designed to operate in the 5 to 6 GHz region. The length and width of main patch are close to /2 and /2 at a center frequency of 5.5 GHz. The distance between bottom radiating edge of main patch and center of feed via is 0.084 _g and the total length of the U-shaped parasitic patch (d) is 1.05The geometrical parameters of the proposed antennas are WR = 5:8 mm, LR = 13:1 mm, WG = 25mm, LG = 30mm, WU = 18mm, LU = 8mm, GH = 0:7 mm, GV = 1:2 mm, and GU = 1:5 mm. An FR4 substrate, whose permittivity is 4.3 with a thickness (h) of 4mm, has been used in this work. The radius of the feed via is 0.4 mm and the length is same as the substrate thickness. The ground and substrate size of the proposed antenna is defined as 25 mm_30 mm for compact transceiver application.III. CALCULATION AND MEASUREMENTThe resonant properties of the proposed antenna have been predicted and optimized using a frequency domain three- dimensional full wave electromagnetic field solver (Ansoft HFSS) and the characteristics of the fabricated antenna have been measured with a vector network analyzer and a far field measurement system.Fig. 2 shows a photograph of the fabricated antenna on a FR4 substrate, and Fig. 3 compares the calculated and measured return loss characteristics of the proposed antenna. The specific values of the resonantFig. 2. Three-dimensional view of the fabricated antenna.Fig. 3. Comparison of calculated and measured results.Fig. 4. Calculated currents distribution: at (a) 5.32 GHz and (b) 6.11 GHz.Fig. 5. Calculated and measured radiation patterns: (a) E-plane at fl, (b) H-plane at fl, (c) E-plane at fh, (d) H-plane at fh.frequency and relative bandwidth are summarized in Table I, where fl and fh represent the first and second resonant frequencies, respectively. The calculated result shows two neighboring resonant frequencies (5.32 and 6.11 GHz), and the frequency band ranges from 4.84 to 6.28 GHz (1.44 GHz). The bandwidth is 26.2% at 5.5 GHz. The measured bandwidth is 1.5 GHz (4.786.28 GHz) with two separate resonant frequencies at 5.12 and 6.08 GHz. The measured as predicted antenna performance showexcellent agreement. Fig. 4 presents the calculated currents distributions at each resonant frequency. As shown in Fig. 4(a), the amplitudes of the currents around non-radiating edges of main patch are strong, and the effect of the parasitic patches is not significant at 5.32 GHz. Therefore, the low resonant frequency is determined by the length of main patch (LR). In addition, there are strong currents flowing around gaps between the main patch and U-shaped parasitic elements at 6.11 GHz as shown in Fig. 4(b). It means that the radiation at high resonant frequency is mainly contributed by strong electromagnetic coupling between three patches. Therefore, the width of horizontal and vertical gaps (GH, GV) and the total length of U-shaped parasitic element (d) are directly related to the wideband impedance matching performance. This shows the reason how U-shaped parasitic patches can extend the bandwidth. The calculated and measured normalized radiation patterns at the first and second resonant frequencies are plotted in Fig. 5, where the “Co (C),” “Co (M),” “Cross (C),” and “Cross (M)” indicate calculated co-polarization, measured co-polarization, calculated cross-polarization, and measured cross-polarization, respectively. As shown in Fig. 5, the designed antenna displays good broadside radiation patterns in the E-plane (XZ plane) and H-plane (YZ plane) at each resonant frequency. It can be seen that the beam peaks of the E-plane are slightly shifted in a right direction due to the feeding position on the main patch, which means that they experience phase difference at each radiating edge of main patch.The measured co-polarization radiation patterns are almost identical to the calculated radiation patterns, while the cross polarization level is somewhat higher than that of the calculated results due to various error mechanisms in measurement, such as multipath in the chamber, positioning error between standard gain horn antenna and antenna under test (AUT). In addition, the higher cross polarization level in H-plane at fh is caused by y-directed currents flowing on the U-shaped parasitic patches as shown in Fig. 4(b). Notable, the radiation characteristics of the proposed antenna are nearly identical to those of the conventional patch antenna. The measured maximum gains of the fabricated antennaare 6.4 and 5.2 dB at 5.12 and 6.08 GHz, respectively.IV. CONCLUSIONIn this paper, a novel wideband microstrip parasitic patch antenna has been proposed, where U-shaped parasitic elements are incorporated close to the radiating edges of a reduced size main patch so as to achieve wideband characteristics, and those two parasitic patches are excited by proximity coupling from the main patch. The wideband impedance matching can be achieved by adjusting either horizontal or vertical gaps between the main patch and parasitic elements. The size of the radiating elements including parasitic elements is 18 mm17.6mm, and the overall dimensions of the designed antenna with ground plane and substrate are 25 mm30 mm4 mm. The measured resonant frequencies are 5.12 and 6.08 GHz, and the bandwidth is 1.5 GHz, which is 27.3% at 5.5 GHz (center frequency). In addition, the radiation patterns of the fabricated antenna are almost identical to those of a conventional microstrip patch antenna at each resonant frequency with more than 5 dB gain. From these results, it can be concluded that implementation of the U-shaped parasitic patch on the radiating edges of the reduced main patch is an effective means of realizing a wideband microstrip antenna having a finite substrate and ground plane.ACKNOWLEDGMENTThe authors would like to thank Prof. Y. Zhang of the Nanyang Technological University, Singapore, for his invaluable assistance.REFERENCES1 D. H. Schaubert, D. M. Pozar, and A. Adrian, “Effect of microstrip antenna substrate thickness and permittivity: Comparison of theories and experiment,” IEEE Trans. Antennas Propag., vol. AP-37, pp. 677682, Jun. 1989.2 H. F. Pues and A. R. 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Antennas Propag., vol. 53, pp. 26452652, Aug. 2005.外文翻译外文翻译带有U型寄生单元的宽带微带贴片天线Sang-Hyuk Wi, Yong-Shik Lee, and Jong-Gwan Yook摘要：本文提出一种含U型寄生单元的宽带微带贴片天线。两个寄生单元都分别合并进了长宽分别为g/2和g/4的长方形贴片的边缘，这样是为了获得宽频的同时实现小型化。主贴片和U型贴片之间相互耦合，是通过水平或垂直的缝隙实现的。而这些缝隙是实现宽带阻抗匹配的主要影响因素。提出的的天线设计制造组装在一块小尺寸的接地面上（25mm30mm），应用在小型无线电发射装置之中。这种安装在FR4介质基片的组装天线的阻抗频宽能达到中心频率5.5GHz赫兹的27.3%(1.5GHz)。测试的辐射方向图同传统贴片天线的类似，在两个谐振频率上的增益仅高出6.4dB和5.2dB。关键词： 寄生贴片天线， U型寄生贴片， 宽频带。一 前言由于对体积紧凑和多功能的无线通信系统的需要，促使在制造多频和宽频的天线方面更倾向于尺寸更加小巧。微带贴片天线如今得到了广泛的应用，这是因为其紧凑，低剖面，高性价比并且重量更轻的特点。然而，这种微带贴片天线的应用却会因为其窄频特点有所限制。存在很多众所周之的方法来提高天线的频带宽度，例如增加基层厚度1，使用较小介电常数的基片1，用各种不同的阻抗匹配和馈电技术2，使用多重谐振3-7，使用槽天线结构等等8。但是，天线的带宽和尺寸通常是相互矛盾的，也就是说，其中一个的改进往往将导致另一个的性能的变坏。近来，不同的技术被提出来增加带宽。文献9-11中，使用短路针形成短路壁于U型贴片、U型槽贴片或L型探针馈电贴片天线的不等臂上，可以获得电小尺寸下的宽频和双频的阻抗带宽。在这篇文章中，将对宽频微带贴片天线采用寄生单元进行分析。两个U型寄生单元安装在探针馈电的长方形贴片天线的辐射边缘，可以获得一个宽频的工作频率。另外，同文献4，5中描述的传统的寄生贴片相比，这种天线更加小巧。这种天线的特性给出了测量与计算结果。而这种天线的几何尺寸在第二部分有所描述。天线的制作和试验验证将在第三部分阐述。二 天线设计图1描绘了这种带有U型寄生单元的贴片宽带微带天线的俯视图和侧面图。该天线由一个半波长探针馈电的矩形贴片和嵌入在矩形贴片辐射边缘的两个U型寄生单元组成。一般来说，矩形贴片天线的长和宽都近似于半波长。然而，主贴片的长(LR)和宽(WR)不同于这种设计。为了保持和体积小相匹配的固有谐振长度，WR被削减至g/4以及LR被定义为g/2,此处g表示导波的波长。探针馈电由垂直通孔穿过基底材料完成。图1.带有U型寄生单元的宽带微带贴片天线几何尺寸该天线为了获得较宽的阻抗带宽具有两个U型寄生单元。利用U型贴片的几何特性，天线的尺寸得以小型化。明显的，尽管两个寄生的贴片被放在了主贴片辐射边缘的附近，主贴片的所有辐射和非辐射边缘都被U型寄生贴片包围着。我们可以观察到主贴片和寄生贴片间的电磁耦合存在于水平的(GH)或者垂直的(GV )间隙中。另外，U型贴片的谐振长度可以通过调整长度(LU)和宽度(WU)来进行控制。该天线的设计是为了应用于5 到 6 GHz的频域范围。主贴片的长和宽在5.5GHZ中心频率附近接近g/2和g/4。主贴片的底部辐射边界和中心馈电点之间的距离是0.084g，与此同时U型寄生贴片的总长度为1.05g .于是该天线的几何参数为WR = 5.8 mm,LR = 13.1 mm, WG = 25mm, LG = 30mm, WU = 18mm, LU = 8mm, GH = 0.7 m