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

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Figure 2.8: Polarization of the waves: (a) linearly polarized, (b) Left-Hand Ellipse Polarized (LHEP) and (c) Right-Hand Ellipse Polarized (RHEP). polarized (LHCP) and when δ = −90 o , the wave is right-hand circularly polarized (RHCP). 2.4 Circularly Polarized Synthetic Aperture Radar Circularly polarized synthetic aperture radar (CP-SAR) is a SAR system, which transmits and receives the microwave signals circularly. Basically, the concept of circularly polarized SAR is similar to the linear polarization SAR. A linearly polarized antenna radiates wholly in one plane containing the direction of propagation. In a circularly polarized SAR, the plane of polarization rotates in a circle making one complete revolution during one period of the wave. The circular polarization can be RHCP or LHCP depends on the vector is turning clockwise (CW) or counter clockwise (CCW) in relation to the time. In the current SAR system (LP-SAR), the basic parameter of the SAR sensor is determined based on the half power beamdwith. The half power beamwidth is used in calculation for both elevation and azimuth direction. In elevation direction, the half power beamwidth (θ ELP ) is employed to calculate the covered area that can illuminate by sensor on the ground (swath width). In azimuth direction, the half power beamwidth (θ ALP ) is needed to determined the synthetic aperture length (L SA ) as shown in following formula (Samuel, et al., 2004) L SA = Rθ ELP (2.21) Here, R is the nearest target range in azimuth plane view as illustrated in Figure 2.9 (Samuel, et al., 2004). The half power beamwidth in linear polarization (θ ELP and θ ALP ) is determined 17
Figure 2.9: Basic principle of aperture synthesis. by the physical size of the antenna width, W and length, L (Mahafza BR., 2000) as formulated θ ELP = λ W and θ ALP = λ L (2.22) In contrary with LP-SAR system, in CP-SAR system the SAR parameters are determined by axial ratio characteristic of the antenna rather than only the physical size of the antenna. To guarantee the SAR sensor operate in circular polarization, the axial ratio of the antenna should have lower than 3 dB at the working frequency. In ideal condition, the perfect circular polarization can be obtained when the axial ratio 0 dB. However, in many reports (Baharuddin et al., 2011 and Yohandri et al., 2012), the axial ratio of the CP antenna very challenging to be realized at 0 dB. Therefore, the 3-dB AR beamwidth is used to define the key parameters of CP-SAR system as following (Rizki Akbar et al., 2010) θ ECP ≤ 3 dB AR and θ ELP (2.23) θ ACP ≤ 3 dB AR and θ ALP (2.24) Where θ ECP is 3-dB AR beamwidth in elevation direction and θ ACP is 3-dB in azimuth direc- 18
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: Substituting (2.12) and (2.13) into
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 and 50: 3.2.6 Radiation pattern In the fiel
Page 51 and 52: Figure 3.6: Rectangular patch arran
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
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Figure 5.15: Simulated and measured
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In Figure 5.18, the antenna gain wi
Page 95 and 96:
Figure 5.20: Array antenna characte
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Figure 3 shows the design and photo
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Figure 5.24: Simulated and measured
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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
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measurement, respectively. Such deg
Page 111 and 112:
Figure 5.40: Relationship between a
Page 113 and 114:
Figure 5.42: Array antenna characte
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BIBLIOGRAPHY single-feed circular m
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antenna for CP-SAR sensor. In the c
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List of Publications Peer-reviewed
Page 121 and 122:
Curriculum Vitae YOHANDRI He was bo
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To perform an electromagnetic simul
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are integrated into MGRID. PATTERN
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properly. After a rectangle is draw
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Figure B.5: Frequency sweep in simu
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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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