【正文】
日 一、課題國內(nèi)外為情況微帶貼片天線體積小、重量輕、薄的平面結(jié)構(gòu)適合與飛行器共形,它的制作工藝簡單,成本低廉,有很大的發(fā)展前景。目前在衛(wèi)星通信、雷達、遙感、導(dǎo)彈、遙測遙控、環(huán)境監(jiān)測、生物醫(yī)學(xué)、便攜式無線電設(shè)備等,貼片天線已被廣泛運用。目前對于貼片的研究主要有以下幾個方面:(1) 多極化方式的研究。貼片天線主要極化方式有線極化,橢圓極化和圓極化。多極化研究意在使天線能發(fā)射或接受多種方式的電磁波,由此能擁有較好的傳輸性能,抗干擾能力也明顯增強。尤其在信息時代的今天,天線輻射的信號越來越多,由此引起的干擾有日趨嚴重,多極化的研究正是基于解決干擾而發(fā)展起來的。(2) 小型化的研究。貼片天線的尺寸大小與其中心頻率有著直接的關(guān)系,當(dāng)輻射較長電磁波時,天線的長度也相應(yīng)比較大,而對于航天器,衛(wèi)星,飛機,個人通信設(shè)備等來說,天線尺寸大小必然是其考量的重要標準。近年來對于小型化的研究比較多,也出現(xiàn)許多有意義的研究理論。(3) 高增益,大帶寬的研究。天線的增益是輻射距離的直接決定因素,擁有好的增益能節(jié)省大量能量,正符合如今節(jié)能低碳的社會目標。大帶寬則是讓天線具有較靈活的選擇余地,當(dāng)外界傳輸條件發(fā)生惡化,天線的的傳輸也盡量不受影響。(4) 多頻段的研究。GSM等通訊系統(tǒng)會工作在多個頻段,由此提出多頻段共用天線的要求,需要在特定頻段上擁有較好的輻射性能。 主要研究成果天線的基礎(chǔ)理論基本成熟,總體來講,天線理論只是電磁理論的分支系統(tǒng),因此在基本理論方面沒有重大突破。天線理論與其他電磁理論有重大區(qū)別在于,實際應(yīng)用的未知性,盡管理論與實際工程都會產(chǎn)生偏差,而天線輻射的偏差比其他電磁理論偏差更明顯,具有更多的未知變數(shù)。(1) 多極化研究成果。對于多極化貼片天線來說,實現(xiàn)的方法大致可分為結(jié)構(gòu)型,切角型,和饋電型。通過構(gòu)建不同的天線結(jié)構(gòu),或者在貼片上切取不同形狀的凹槽,或者采用多點饋電,多相位饋電等方式來獲得多極化的輻射效果。(2) 小型化研究成果。小型化的主要思想為讓盡量小的范圍內(nèi)有盡量長的電流流過,即是讓貼片上的等效電路越長越好。另外也有提出在饋線中加入短路電流,天線中加入阻抗等方法來實現(xiàn)小型化。(3) 高增益,大帶寬研究成果。目前的研究方向主要為加入不同介電常數(shù)的介質(zhì)層,增加介質(zhì)層的厚度來實現(xiàn)高增益,大帶寬的效果,除此之外選擇合理的饋電方式,也是較為重要的影響因素。(4) 多頻段研究成果。解決多頻段問題的方法主要有以下兩種:加入多層貼片,即每層貼片輻射各自頻段信號,整個天線即可實現(xiàn)多頻段輻射;分型理論設(shè)計天線,分形具有自相似屬性,幾何結(jié)構(gòu)的自相似屬性說明它具有多頻帶特點。 發(fā)展趨勢 隨著通信要求的越來越高,小型化,高增益,多極化為發(fā)展的趨勢。個人通信的崛起是將來較長一段時間的主題,而個人通信終端設(shè)備必然要解決的問題有頻率復(fù)用問題,天線功率問題,天線尺寸問題。而天線的許多參數(shù)存在著自相矛盾關(guān)系,比如天線尺寸越小,其增益也相應(yīng)小,而不能做到面面俱全。當(dāng)頻率達到飽和,要增加通信容量就顯得比較困難,通過不同的極化方式,不同的輻射方向來實現(xiàn)通信容量的增加,相形之下更加具有可行性和簡易性。 存在問題微帶天線的本身固有特性,低功率,窄帶寬,高損耗等在天線性能表現(xiàn)上不夠優(yōu)秀;貼片天線尺寸小,在其貼片上刻畫凹槽即需要很高的技術(shù)要求,作為微波器件,微小的改變對波形的改變都是巨大的;貼片天線需要的介質(zhì)層在工程上是又一個難題,批量生產(chǎn)的介質(zhì)材料得不到保證,厚度與雜質(zhì)問題需要進一步解決。相信隨著科技的發(fā)展,制作工藝的精良,微帶天線必然會有美好的前景。五、主要參考文獻 1 張鈞.微帶天線理論與工程.北京:國防工業(yè)出版社,1988,42~2462 .Broadband microstrip patch antenna on micromatchined silicon substrates.Artech House,1998,44~1243 .Microstrip antennas.IEEE APSlnt.Symp.Digest,1972,35~644 殷際杰.微波技術(shù)與天線——電磁波導(dǎo)行與輻射工程.北京:電子工業(yè)出版社,2004,219~2435 謝擁軍等.Ansoft HFSS基礎(chǔ)及應(yīng)用.西安:西安電子科技大學(xué)出版社,2007,10~876 李磊,謝擁軍,2006,基于固定實鏡像平面波展開的快速多極子方法計算微帶結(jié)構(gòu)問題,電子學(xué)報,33(12):2153~1567 蘇東林,雷軍,王冰切,2007,系統(tǒng)電磁兼容技術(shù)綜述與展望,宇航計測技術(shù),(21):34~388 謝擁軍,辛娟,王鵬,2006,波導(dǎo)縫隙陣天線的快速優(yōu)化設(shè)計,電子學(xué)報,34(9):1726~17289 楊銳,謝擁軍,王鵬等,2007,含有左手介質(zhì)雙層基底的亞波長諧振腔微帶天線研究,物理學(xué)報,56(8):4504~450810 楊銳,謝擁軍,李曉峰等,2008,導(dǎo)向介質(zhì)諧振響應(yīng)的Floquet 模分析,物理學(xué)報,58(2):901~90711 張鈞等,1988,微帶天線理論與工程,北京:國防工業(yè)出版社12 VIRRGA K L,RAHMAT—SAMH Y. wideband evaluation of mobile munication antenna using[Z]or[Y] matrix interpolation with the method of moments[J].IEEE Trans on Antennas Propagation,47(1):65~68.13 POZAR D M. and scattering from a micro strip patch on a uniaxial substrate[J].IEEE Trans on Antennas Propagation,35(6):613~62114 Cameron R coupling matrix synthesis techniques for microwave Theory and Techniques,51(1):1~1015 Bayliss condition for the numerical solution of elliptic equations in exterior J APPL MATH,42:430~45116 Daniel J coupling between antennas for emission or receptionapplication to passive active Transactions on Antennas and (2):347~34917 Amari S,Rosenberg synthesis of a new class of bandstop Transaction on Microwave Theory and (2):607~61618 JACKSON D R. RCS of rectangular micro strip patch in a substrate—superstrate geometry[J].IEEE Trans on Antennas Propagation,38(1):2~8.19 Jin W J V engineer’s approach for terminating finite element meshes in scattering APS Symposium :1216~1219 附錄4燕 山 大 學(xué)本科畢業(yè)設(shè)計(論文)外文翻譯課題名稱:圓形和矩形微帶貼片圓極化性能仿真分析學(xué)院(系):信息科學(xué)與工程學(xué)院 年級專業(yè):09通信工程 1班 學(xué)生姓名: 何鑫 指導(dǎo)教師:邢光龍教授 完成日期: A Novel Method for Designing DualFrequency Slot Patch Antennas with Two PolarizationsWU Di1, OH ISH I BA SH I H idekazu2, SEO Kazuyuk i2, I NA GA K IN aok i3(1. Department of Communication Engineering , Shang hai University , Shang hai 200072, China。2. Kojima R amp。D Center, Kojima Press Industrial Co Ltd , Aichi 470—0207, Japan。3. Nagoya Institute of Technology, Nagoya 466—8555, Japan)Abstract: This paper presents a new method for designing a dualfrequency patch antenna with circular and linear polarizations. Dualfrequency operations are behaved by etching two narrow slots close to the radiating edges of a rectangular patch. The circular polarization at the lower resonant frequency of the dualfrequency antenna can be achieved by setting a perturbation segment at an appropriate location in the patch element, and placing the feed point on the diagonal axis. Several experimental results of a designed antenna show the good characteristics for circular and linear polarizations at both resonant frequencies.CLC number: Document code: AKey words: dualfrequency。 slot patch antennas。 linear polarization。 circular polarizationIn radar and munication systems, dualfrequency operations are often required. Specially, in modern mobile global position system (GPS), it will be desirable that one of two frequencies is the circular polarization. Planar antenna has been investigated for multifrequency very well since it is advantageous in low cost, low weight and conform ability. Early dualfrequency planar antenna is multilayered stackedpatch structure, and the radiating element is used to be circular[1], annular[2], rectangular[3]and triangular patches[4]. Recently, a dualfrequency antenna is introduced in which the structure is dingle layer patch with two slots close to the radiating edges, and good performances of simultaneous impedance matching and gain are demonstrated for both resonant frequencies. However, all the conventional investigations are only for the case in which the antenna polarization is linear, while the dualfrequency antenna with circular polarization has not been touched yet.In this paper, we present a design method of a dualfrequency antenna with circular and linear polarizations based on the conventional investigation for the dualfrequency linear polarization antenna[5~7], Two resonant frequencies are determined by adjusting the size of the patch element and the slot, as well as the location of the