許博文臺灣大學：電信工程學研究所賴宗民Lai, Tzung-MingTzung-MingLai2007-11-272018-07-052007-11-272018-07-052005http://ntur.lib.ntu.edu.tw//handle/246246/58959本論文中，我們主要是提出一種用微帶線饋入的圓極化微帶天線，經由模態分析法加以分析。首先將針對各式圓極化微帶天線進行介紹。 理論分析以共振腔模型為基礎，求解圓形微帶天線在共振腔中的模態。由模態分析的結果，可推導出在共振腔金屬面上的電流分布情形。而在本論文中是採直接饋入圓形微帶天線，但爲了增加頻寬和極化程度，經由結合循序旋轉的設計技巧，在此設計了微帶線饋入之圓形極化微帶線天線陣列。從模擬與量測結果當中，我們可以明顯的發現使用循序旋轉的技巧的 1x2 陣列天線，在頻寬上有明顯的提升。 由於本論文中所提出的天線是由微帶線所饋入，因此本身具有結構簡單，輕薄短小， 低姿態，易於與電路結合且製造的好處，故這些天線適合應用於高頻(毫米波)頻段。In this thesis, a circularly polarized patch antenna fed by a microstrip-line is designed for the 60GHz (V-Band) communication system. In order to increase the bandwidth and polarization purity, a wide bandwidth microstrip-line fed circularly polarized patch array is proposed by combining the principle of sequential rotation technique and the 90° phase delay line for spatial rotation. Based on the cavity model, the Helmholtz’s equation is solved to obtain the modes exist in the circular cavity resonator. From the mode analysis results, the electric current distribution patterns on the patch and the ground plane are computed. Because we need increase the bandwidth and the polarization purity, a microstrip-line fed circularly polarized patch array is proposed by employing the principle of sequential rotation technique. The simulated and measured return losses are presented for an 1x2 array with and without sequential rotation technique. Significant increase in the return loss bandwidth is found in the array with sequential rotation. Because the proposed antenna is fed by the microstrip-line, in addition to the advantages of simple structure, lightweight, low profile, easy to combine with the circuit, and fabricate, this antenna is especially suitable for millimeter-wave application.Chapter 1 Introduction…………………………………….. 1 1.1 Motivation and Literature Survey…………………1 1.2 Chapter Outlines…………………………………..4 Chapter 2 Analysis of Circularly Polarized Microstrip Antenna………………………………..…………9 2.1 Various Types of Circularly Polarized Microstrip Antenna………………………………………….. 9 2.1.1 Resonator Antenna………………………. 9 2.1.2 Traveling Wave Antenna……………….. 10 2.2 Theoretical Analysis Base On Cavity Model……. 11 2.2.1 Cavity Model…………………………….11 2.2.2 Electric and Magnetic Fields — TMz…. 12 2.2.3 Equivalent Current Densities and Field Radiated………………………………… 14 2.3 Necessary Conditions for Circularly Polarized Radiation……………………………………...… 15 III Chapter 3 Design of CP Patch Antenna Fed by Microstrip Line……….…………………………………… 29 3.1 Concept of Generating Circular Polarization……. 29 3.2 Mode Limiting Effect Relating to Current Pattern on The Ground Plane…………………………31 3.3 Design of Circularly Polarized Patch Antenna Fed by Microstrip Line…………………………. 34 3.3.1 Sequentially Rotated Feeding Technique… 35 3.3.2 Design CP Patch 1D Array Fed by Microstrip Line at 5GHz……………………….…….. 36 3.3.3 Design Single Element CP Patch Antenna Fed by Microstrip Antenna at 60GHz….... 37 3.3.4 Design CP Patch 1D Array Fed by Microstrip Line at 60GHz…………………………… 38 Chapter 4 Conclusions…………..………………..…….… 62 Appendix A Simple Formula for Axial Ratio Calculations………………………………….. 63 IV Appendix B Derivation of the Equivalent Circuit for CP Microstrip Antenna……………………... 71 References…………………………………………...………..76 V List of Figures Chapter 1 Fig. 1.1 Typical feeding approaches of patch antennas. (a) Coaxial feed, (b) Aperture-coupled feed, (c) Microstrip line feed, and (d) CPW feed ………………………………………………………….…8 Chapter 2 Fig. 2.1 Various types of circularly polarized antenna………………….19 Fig. 2.2 Two kinds of feeding network for dual-fed patch antenna……..20 Fig. 2.3 Geometry of circular microstrip patch antenna………………...21 Fig. 2.4 Cavity model and equivalent magnetic current density for circular microstrip patch antenna…………………………...…22 Fig. 2.5 Typical polarization circle……………………………………...23 Fig. 2.6 Far field radiation approximation of arbitrary current sources...24 Fig. 2.7 Magnetic current distribution of circular patch antenna TM11…25 Fig. 2.8. Instantaneous magnetic current distribution plot of circular patch antenna versus variable ………………...…26 VI Chapter 3 Fig. 3.1(a) Equivalent circuit of linearly polarized circular microstrip antenna………………………………………………………39 Fig. 3.1(b) Equivalent circuit of linearly polarized mode split into two orthogonal modes………………………………………40 Fig. 3.2 Fundamental configuration of two singly-fed type CP circular patch antenna……………………………………….41 Fig. 3.3 Surface current patterns on the ground plane of circular cavity, TM11 mode and TM21 mode…………………………………42 Fig. 3.4 Surface current patterns on the ground plane of circular cavity, TM31 mode and TM41 mode…………………………………43 Fig. 3.5 Surface current patterns on the ground plane of circular cavity, TM02 mode and TM12 mode…………………………………44 Fig. 3.6 Sequentially rotated array feeding…………………………..45 Fig. 3.7 Configuration of the microstrip line fed 1×2 circularly polarized circular patch array with sequentialy rotation……46 Fig. 3.8 Simulated and measured return losses and axial ratio of the microstrip line fed 1×2 circularly polarized circular patch array with sequential rotation against frequency…………..47 VII Fig. 3.9 Simulated and measured radiation pattern of the microstrip line fed 1×2 circularly polarized circular patch array without sequential rotation patch antenna at 5.15GHz and 5.25GHz.... 48 Fig. 3.10 Simulated and measured radiation pattern of the microstrip line fed 1×2 circularly polarized circular patch array without sequential rotation patch antenna at 5.35GHz and 5.4GHz….. 49 Fig. 3.11 The measured gain comparisons of RHCP and LHCP variations versus frequency………………………………….. 50 Fig. 3.12 Configuration of the microstrip line fed circular patch antenna……………………………………………………….. 51 Fig. 3.13 Simulated return losses and axial ratio of the microstrip line fed patch antenna against frequency……………………………... 52 Fig. 3.14 Simulated radiation pattern to of the patch antenna fed by Microstrip line……………………………………………..…. 53 Fig. 3.15 Configuration of the microstrip line fed 1×2 circularly polarized circular patch array………………………………... 54 Fig. 3.16 Simulated return losses and axial ratio of the microstrip line fed 1×2 circularly polarized circular patch array without sequential rotation against frequency……………………………………55 Fig. 3.17 Simulated radiation pattern of the microstrip line fed 1×2 circularly polarized circular patch array without using sequential rotation patch antenna at 60.5GHz……………….56 VIII Fig. 3.18 Simulated and measured return losses of the microstrip line fed 1×2circularly polarized circular patch array with sequential rotation against frequency……………………………………57 Fig. 3.19 Simulated axial ratio of the microstrip line fed 1×2 circularly polarized circular patch array with sequential rotation against frequency……………………………………………………..58 Fig. 3.20 Simulated radiation pattern of the microstrip line fed 1×2 circularly polarized circular patch array with using sequential rotation patch antenna……………………………………….59 Fig. 3.21 Simulated radiation pattern of the microstrip line fed 1×2 circularly polarized circular patch array with using sequential rotation patch antenna………………………………………60 Fig. 3.22 The measured gain comparisons of RHCP and LHCP variations versus frequency arrays………………………….61 Fig. A.1 Combination of two quasi-linearly polarized signals……….67 Fig. B.1 Fundamental configuration of singly-fed rectangular patch..74 Fig. B.2 Equivalent circuit for rectangular circularly polarized antenna………………………………………………………75 IX List of Tables Chapter 1 Table 2-1 The zeros of the derivative of the Bessel function …………………………………………………27 Table 2-2 The zeros, , of the first ten modes in ascending order, mode indices and numbers of maximum field…………..28 Table 4-1 The comparison between arrays with and without sequential rotation………………………………………………….62 Table A-1 Comparison between approximate and exact AR of CP wave with perfectly polarized radiating elements………68 Table A-2 Comparison between approximate and exact AR of CP wave with same-sense quasi-linearly polarized radiating elements…………………………………………………70870987 bytesapplication/pdfen-US圓極化微帶天線Circularly PolarizedPatch Antennathesishttp://ntur.lib.ntu.edu.tw/bitstream/246246/58959/1/ntu-94-R92942013-1.pdf