Development of Circularly Polarized Microstrip ... - CEReS - åèå¤§å¦

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equired (Tamakuma and Iwasak, 2003 and James and Hall, 1989). Microstrip antenna on its own doesnt generate circular polarization; subsequently, some changes should be done to the patch antenna to be able to generate the circular polarization (Suzuki et al., 1987). The most commonly used feeding techniques in circular polarization generation are dual feed and single feed. However, with some phase adjustment, the multiple feed also can be employed to generate the circular polarization antenna (Yohandri et al., 2012). 3.3.1 Dual feed circularly polarized microstrip antenna A circularly polarized microstrip antenna can be realized by exciting two orthogonal modes with equal magnitudes, which are in phase quadrature. The simplest way to obtain CP is using two feeds at orthogonal as the 90 o phase shift between the fields in the microstrip antenna. The two feed points are chosen perpendicular to each other. Figure 3.5 show the dual feed configuration for square microstrip antenna (SMSA) and circular microstrip antenna (CMSA). Figure 3.5: Dual-feed (a) SMSA and (b) CMSA (Girish and Ray, 2003). With the help of external polarizer, the microstrip patch antenna is fed by equal in magnitude and orthogonal feed. Several transmission lines can be used to realize the power divider network. The quadrature phase difference can be obtained by feeding the element with a 90 o power divider or 90 o hybrid (Balanis, 2005) as shown in Figure 3.6. 37
Figure 3.6: Rectangular patch arrangements for circular polarization: (a) Through a power divider and (b) Through a 90 o hybrid (Balanis, 2005). 3.3.2 Single feed circularly polarized microstrip antenna Single feeding techniques are very common with microstrip antennas as they are simple, easy to manufacture, low in cost and compact in structure as shown in Figure 3.7. It eliminates the use of complex hybrid polarizer, which is very complicated to be used in an antenna array (Haneishi et al., 1982). In order to achieve circular polarization using only single feed two degenerate into modes should be exited with equal amplitude, and in-phase quadrature have to be induced. Since basic shapes microstrip antenna produce linear polarization, there must be some changes in the patch design to produce circular polarization. Perturbation segments are used to split the field into two orthogonal modes with equal magnitude and 90 o phase shift. To realize Figure 3.7: Single-feed arrangements for circular polarization microstrip antennas: (a) Square, (b) Circular and (c) Elliptical. the circular polarization using single feed, the two orthogonal mode in patch surface must be set properly to get same amplitude but 90 o out of phase with respect to other mode. Figure 3.8 shows a nearly square patch antenna having physical dimensions a and b with b > a. The circular polarization either RH or LH in this path can be generated by fed along one of the two 38
Page 1 and 2: Development of Circularly Polarized
Page 3 and 4: Abstract The discussion about devel
Page 5 and 6: Acknowledgements First and foremost
Page 7 and 8: CONTENTS 3 Circularly Polarized Mic
Page 9 and 10: List of Figures 1.1 Electric field
Page 11 and 12: LIST OF FIGURES 5.13 Photograph of
Page 13 and 14: List of Tables 2.1 Parameters of CP
Page 15 and 16: in linear polarization has some fla
Page 17 and 18: polarization (RHCP) and left-handed
Page 19 and 20: BIBLIOGRAPHY Bibliography [1] Birk
Page 21 and 22: Chapter 2 Circularly Polarized Synt
Page 23 and 24: generates all the necessary timing
Page 25 and 26: line platform flight trajectory is
Page 27 and 28: Figure 2.6: Range ambiguities: Port
Page 29 and 30: Substituting (2.12) and (2.13) into
Page 31 and 32: Figure 2.9: Basic principle of aper
Page 33 and 34: CP-SAR geometry, the slant range ,
Page 35 and 36: Figure 2.12: The required (a) θ EC
Page 37 and 38: 2.5.2 Design of CP-SAR system 2.5.2
Page 39 and 40: BIBLIOGRAPHY Figure 2.15: Design of
Page 41 and 42: BIBLIOGRAPHY [14] Steven Z., Unmann
Page 43 and 44: developments of novel microstrip an
Page 45 and 46: to feed or excite a microstrip patc
Page 47 and 48: defines as the ratio of the power g
Page 49: 3.2.6 Radiation pattern In the fiel
Page 53 and 54: diagonals axis. The area of the per
Page 55 and 56: By substitute eq. (3.7-3.9) to (3.1
Page 57 and 58: 3.4.1 Linear array Among the differ
Page 59 and 60: provide additional variables which
Page 61 and 62: The beam area or solid angle or Ω
Page 63 and 64: 2005). An array of even number of i
Page 65 and 66: BIBLIOGRAPHY m = 8 cos(mu) = 128z 8
Page 67 and 68: BIBLIOGRAPHY [21] Rahmani M., Tavak
Page 69 and 70: Figure 4.1: Design methodology. 56
Page 71 and 72: Figure 4.2: Flow chart of the anten
Page 73 and 74: Figure 4.3: Diagram of required ant
Page 75 and 76: easy if you have the right equipmen
Page 77 and 78: Chapter 5 Results and Discussion 5.
Page 79 and 80: Figure 5.2: Geometry design of prop
Page 81 and 82: terminals during the radiation proc
Page 83 and 84: 5.1.4 Radiation characteristic The
Page 85 and 86: Figure 5.11: Measured and simulated
Page 87 and 88: the physical length, L, and the eff
Page 89 and 90: Figure 5.13: Photograph of the fabr
Page 91 and 92: Figure 5.15: Simulated and measured
Page 93 and 94: In Figure 5.18, the antenna gain wi
Page 95 and 96: Figure 5.20: Array antenna characte
Page 97 and 98: Figure 3 shows the design and photo
Page 99 and 100: Figure 5.24: Simulated and measured
Page 101 and 102:
5.4 Broadband circularly polarized
Page 103 and 104:
Figure 5.29: Axial ratio (AR) plott
Page 105 and 106:
Figure 5.33: A 3D beam pattern of t
Page 107 and 108:
Figure 5.34: Dolph-Chebyshev array
Page 109 and 110:
measurement, respectively. Such deg
Page 111 and 112:
Figure 5.40: Relationship between a
Page 113 and 114:
Figure 5.42: Array antenna characte
Page 115 and 116:
BIBLIOGRAPHY single-feed circular m
Page 117 and 118:
antenna for CP-SAR sensor. In the c
Page 119 and 120:
List of Publications Peer-reviewed
Page 121 and 122:
Curriculum Vitae YOHANDRI He was bo
Page 123 and 124:
To perform an electromagnetic simul
Page 125 and 126:
are integrated into MGRID. PATTERN
Page 127 and 128:
properly. After a rectangle is draw
Page 129 and 130:
Figure B.5: Frequency sweep in simu
Page 131 and 132:
Figure B.8: Three-dimensional far-f
Page 133 and 134:
Figure C.1: (a) Seven Mini PCB Prot
Page 135 and 136:
Figure C.3: Etching tank and chemic
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