The Design and Analysis of a Phased Array Microstrip Antenna for a Low Earth Orbit ...

95 Pages·2012·2.67 MB·English

NAVAL POSTGRADUATE SCHOOL
Monterey, California
AD-A284 791
(cid:127) TTHESI E219
DTIC
SELECTE
THESIS, SEP 2 6 1994
F
THE DESIGN AND ANALYSIS OF A PHASED ARRAY
MICROSTRIP ANTENNA FOR A LOW EARTH ORBIT
COMMUNICATION SATELLITE
by
William Lee Barfield
June 1994
Thesis Advisor: Richard Adler
Approved for public release; distribution is unlimi# 1.
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4. TITLE AND SUBTITLE S. FUNDING NUMBERS
THE DESIGN AND ANALYSIS OF A PHASED ARRAY MICROSTRIP
ANTENNA FOR A LOW EARTH ORBIT COMMUNICATION
SATELLITE
6. AUTHOR(S)
Barfield, William L.
7. PERFORMING ORGANIZATION NAME(S) AND ADDRESS(ES) U. PERFORMING ORGANIZATION
Naval Postgraduate School REPORT NUMBER
Monterey, CA 93943-5000
9. SPONSORING /MONITORING AGENCY NAME(S) AND ADDRESS(ES) 10. SPONSORING / MONITORING
AGENCY REPORT NUMBER
11. SUPPLEMENTARY NOTES
The views expressed in this thesis are those of the author and do not reflect the official policy or position of the
Department of Defense or the U.S. Government.
12a. DISTRIBUTION/AVAILABILITY STATEMENT 12b. DISTRIBUTION CODE
Approved for public release; distribution is unlimited.
13. ABSTRACT (Maximum 200 words)
A Naval Postgraduate School spacecraft design class proposed a multiple beam, phased array, microstrip antenna as part of the
preliminary design of a low earth orbit communication satellite. The antenna must provide coverage over the satellite's entire
field of view while both uplink and down-link operate simultaneously on the same L-band frequency.
This thesis assesses the feasibility of the antenna proposed in that preliminary design. Design tradeoffs for a microstrip array
constrained by both available surface area and a limited mass budget are examined. Two different substrate materials are
considered in terms of weight and performance. Microstrip patch theory is applied to array element design and layout and
antenna array theory is applied to determine phase and amplitude coefficients. The focus of the design is on obtaining the
desired beam shape and orientation, given antenna size constraints. A corporate feed method is discussed and a general design
presented.
Antenna performance is predicted through the use of a computer model based on Modal Expansion theory and results are
plotted in a series of graphs which demonstrate the limitations of the proposed design.
DTQIUCA INULI~CTIED %3
14. SUBJECT TERMS 1S. NUMRER OF PAGES
W
Microstrip Antenna, Low Earth Orbit Communication, Modal Expansion Theory,
L-band, Satellite 16. PRICE CODE
17. SECURITY CLASSIFICATION 18. SECURITY CLASSIFICATION 191. SECURITY CLASSIFICATION 20. LIMITATION OF ABSTRACT
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Approved for public release; distribution is unlimited.
THE DESIGN AND ANALYSIS OF A PHASED ARRAY MICROSTRIP
ANTENNA FOR A LOW EARTH ORBIT COMMUNICATION SATELLITE
by
William Lee Barfield
Lieutenant, United States Naval Reserve
B.S., North Carolina State University, 1984
Submitted in partial fulfillment
of the requirements for the degree of
MASTER OF SCIENCE IN ELECTRICAL ENGINEERING
from the
NAVAL POSTGRADUATE SCHOOL
June 1994
.13
Author: ;ejcI
Wil iam Lee Barfield
Approved by:
_ ___ __
Richar Aer, Thesis Advisor
Rudolph Panholzer, Seco d Advisor
Michael A. Morgan, Ch6irman
Department of Electrical and Computer Engineering
ii
ABSTRACT
A Naval Postgraduate School spacecraft design class
proposed a multiple beam, phased array, microstrip antenna as
part of the preliminary design of a low earth orbit conmmunica-
tion satellite. The antenna must provide coverage over the
satellite's entire field of view while both uplink and down-
link operate simultaneously on the same L-band frequency.
This thesis assesses the feasibility of the antenna
proposed in that preliminary design. Design tradeoffs for a
microstrip array constrained by both available surface area
and a limited mass budget are examined. Two different
substrate materials are considered in terms of weight and
performance. Microstrip patch theory is applied to array
element design and layout and antenna array theory is applied
to determine phase and amplitude coefficients. The focus of
the design is on obtaining the desired beam shape and orienta-
tion, given antenna size constraints. A corporate feed method
is discussed and a general design presented.
Antenna performance is predicted through the use of a
computer model based on Modal Expansion theory and results are
plotted in a series of graphs which demonstrate the limita-
tions of the proposed design. Accesion For
NTIS CRA&I
DTiC TAB [J
U,;an(cid:127),ou:;ze'J [
Justification
By .....................
Dist. ibution I
iii Availability Codes
Avail andlor
Dist Special
TABLE OF CONTNTS
I. INTRODUCTION ................... 1
A. BACKGROUND ............... .................. 1
B. SYSTEM CONCEPT ............. ................ 2
C. SYSTEM DESIGN .............. ................. 3
D. ANTENNA PERFORMANCE REQUIREMENTS ..... ....... 6
II. DESIGN CONSIDERATIONS ............ ............... 7
A. SPACECRAFT CONFIGURATION ......... ........... 7
1. Overview ............... ................. 7
2. Size Constraints ........... ............. 7
B. ANTENNA CONFIGURATION .......... ............. 8
C. MICROSTRIP PATCH THEORY .......... ............ 8
1. Radiation Mechanisms ....... ........... .. 10
2. Patch Parameters ......... ............. 12
D. ARRAYS ............... .................... 14
1. Theory ............. .................. 14
2. Beam Synthesis ......... .............. 16
III. ANTENNA DESIGN ............. ................. .. 18
A. MICROSTRIP PATCH DESIGN' ..... ............ .. 18
1. Substrate Material ......... ........... 18
2. Patch Dimensions ......... ............. 22
B. PLANAR ARRAY DESIGN' .......... .............. .. 23
1. Element Spacing .......... .............. 24
2. Excitation Coefficients ...... .......... .. 24
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3. Antenna Gain ............... 25
4. Feed Methods ......... ............... ..27
5. Feed Design .......... ................ ..29
C. SUMMARY .............. .................... .. 29
IV. PERFORMANCE ANALYSIS ........... ............... 31
A. ANTENNA MODEL ............ ................. ..31
1. Infinite vs. Finite Arrays ... ........ .. 31
2. Edge Effects ......... ............... ..32
3. Input Impedance ........ .............. ..32
B. SOFTWARE MODELS ............ .............. ..32
1. Method of Moments ........ ............. ..32
2. Modal Expansion Model ...... ........... .. 33
C. MODELING SCENARIO .......... ............... ..33
D. RESULTS .............. .................... .. 34
1. Radiation Patterns ....... ............ .. 34
2. Pattern Separation ....... ............ .. 35
3. Antenna Footprint ........ ............. .. 36
V. ALTERNATIVE DESIGN ........... ................ 38
A. ANTENNA CONFIGURATION ........ ............. .. 38
B. ANTENNA ORIENTATION .......... .............. 39
VI. SUMMARY ................ ...................... .. 40
A. ANALYSIS AND DESIGN .......... .............. 40
B. PERFORMANCE EVALUATION ....... ............ .. 40
C. CONCLUSIONS ............ .................. .. 41
D. FUTURE THESIS OPPORTUNITIES ...... .......... .. 42
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APPENDIX A LINK BUDGET SUMMARY ............. 43
APPENDIX B I. MASS ESTIMATES ......... ............ 44
II. SUMMARY .......... ................ .. 46
APPENDIX C I. PATCH DESIGN ......... ............. 47
II. GAIN ........... ................. .. 48
APPENDIX D EXCITATION COEFFICIENTS ...... ........... .. 49
APPENDIX E ARRAY FACTOR PLOTS ......... ............. 55
APPENDIX F I. DESIGN.FOR ........... .............. 61
II. M1CARY.FOR ......... .............. 63
III. GEOM.FOR ......... ............... ..70
APPENDIX G I. RADIATION PATTERNS ..... .......... .. 72
II. PATTERN SEPARATION ..... .......... .. 75
III. ANTENNA FOOTPRINT ...... ........... .. 76
LIST OF REFERENCES ............. ................... .. 80
BIBLIOGRAPHY ................. ...................... 83
INITIAL DISTRIBUTION LIST .......... ................ ..85
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LIST OF TABLES
TABLE I-i. ANTENNA PARAMETERS ............ 6
TABLE III-l. PARAMETERS FOR A SINGLE MICROSTRIP
PATCH .............. ................... .. 23
TABLE 111-2. BEAM 1 EXCITATION COEFFICIENTS .. ...... ..25
TABLE A-I. LINK BUDGET [REF. 1]. .... ........... ..43
TABLE D-1. BEAM 1 EXCITATION COEFFICIENTS .. ...... ..49
TABLE D-2. BEAM 2 EXCITATION COEFFICIENTS .. ...... ..50
TABLE D-3. BEAM 3 EXCITATION COEFFICIENTS .. ...... ..51
TABLE D-4. BEAM 4 EXCITATION COEFFICIENTS .. ...... ..52
TABLE D-5. BEAM 5 EXCITATION COEFFICIENTS .. ...... ..53
TABLE D-6. BEAM 6 EXCITATION COEFFICIENTS .. ...... ..54
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LIST OF FIGURES
Figure 1.1. System Architecture ......... ............ 3
Figure 1.2. L-Band Beam Orientation ....... .......... 5
Figure 2.1. Phased Array Antenna ........ ........... 9
Figure 2.2. Rectangular Microstrip Patch .... ....... 10
Figure 2.3. Array Coordinate System ..... .......... .. 16
Figure 3.1. Effect of er on Width of a Microstrip
Patch ............. ................... .. 20
Figure 3.2. Effect of Height and er on Length of a
Microstrip Patch ........ ............. .. 21
Figure 3.3. Beam 1 Array Factor (ý=90°) .... ........ .. 26
Figure 3.4. Beam 1 Array Factor (ý=00) ..... ........ 26
Figure 3.5. Coax Corporate Feed ....... ............ .. 30
Figure 3.6. Antenna Panel Assembly .... .......... .. 30
Figure 4.1. Beam 1 Radiation Pattern (*=900) .. ..... .. 35
Figure 4.2. Simultaneous Beam Patterns ... ........ ..36
Figure 4.3. Beam 2 Relative dB Gain Footprint ....... ..37
Figure E-1. Beam 1 Array Factor (ý=90°) .... ........ .. 55
Figure E-2. Beam 1 Array Factor (0=00) ... ........ .. 55
Figure E-3. Beam 2 Array Factor (ý=90°) .... ........ .. 56
Figure E-4. Beam 2 Array Factor (ý=0°) ... ........ .. 56
Figure E-5. Beam 3 Array Factor (ý=900) ...... .... ... 57
Figure E-6. Beam 3 Array Factor (ý=0°) ... ........ .. 57
Figure E-7. Beam 4 Array Factor (ý=900) .... ........ .. 58
Figure E-8. Beam 4 Array Factor (ý=0°) ... ........ .. 58
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Figure E-9. Beam 5 Array Factor (ý=900) .... ........ .. 59
Figure E-10. Beam 5 Array Factor (ý=0o) ... ........ .. 59
Figure E-11. Beam 6 Array Factor (ý=900) .... ........ .. 60
Figure E-12. Beam 6 Array Factor (*=0) ... ........ .. 60
Figure G-1. Beam 1 Radiation Pattern (ý=90.) ..... 72
Figure G-2. Beam 2 Radiation Pattern (ý=90Q) .. ..... .. 72
Figure G-3. Beam 3 Radiation Pattern (ý=90) .. ..... .. 73
Figure G-4. Beam 4 Radiation Pattern (ý=90) .. ..... .. 73
Figure G-5. Beam 5 Radiation Pattern (ý=90) .. ..... .. 74
Figure G-6. Beam 6 Radiation Pattern (ý=900) .. ..... .. 74
Figure G-7. Simultaneous Radiation .... .......... .. 75
Figure G-8. Simultaneous Radiation .... .......... .. 75
Figure G-9. Simultaneous Radiation .... .......... .. 76
Figure G-10. Beam 1 Relative dB Gain Footprint ....... .. 76
Figure G-11. Beam 2 Relative dB Gain Footprint ..... ... 77
Figure G-12. Beam 3 Relative dB Gain Footprint ....... ..77
Figure G-13. Beam 4 Relative dB Gain Footprint ..... ... 78
Figure G-14. Beam 5 Relative dB Gain Footprint ....... ..78
Figure G-15. Beam 6 Relative dB Gain Footprint ....... ..79
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