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BTAIN AUTHORITYBETTER COPY 0l ERR=ATAOUT OP PRINT SOD / z 3 RECEIPT TYPE & FRTO R ISA ANNOUNCEMENT 135 PAS ORA la PAGES 19 SHEETS 20 LOW LtMIT 21 0 MAGNETIC TAPE 'VOL ISSUE LWGA PC MFU 5l SLASTLOAN PC [EQSuMM .M[ OCARDS TEcx ,16I1o E]-QNO .SCRIP- CO PY M F4 i l: I N S M K I R [ I K Z P I E 4STOCK RECEIVEDS OC FORRECIVEDFOR# SALE!.IE 5 aLOANOAN ETC.TC. 1414 REPRODUCTION ( TRUCTiONS M.AKE MICRO)& 1C8!, 22 PRICES "# PC MAP DUE BILOWBACK -111 YE 0 U.~~7f-UMI - rWEPPC OUT PRINT 1S PRESTOCK iUI fXj 7 J~ P ' W eof NO I IUPI 2UP EP MNBx-1MmmDEMAND TRANSACTION 23 CATEGORY 24 DISTR CODE 125 INITIALS I I NOT FULLY NEW 0 IDUPE ISUPER- PRIOR NO 1 4' 7 PC DE IN A LEGIBLE 5l ITEM j ~ SEDES L~NUMBERIT %UP 2 5 8 PC PRINT COLOR5 7 2UP 3 6 9 PCSOURCE26FLFR127PBI TO ORDERPPRMCOABLT IODEMIX SAME STOC CODE­ cop 0REPORT NUMBERS IKREF) 0 .16 REMARKS 9 RELATED DOCUMENT f ~ ~ ~~t-r TU 10 CONTRACTING OFFICE-BILLING CODE v 2$ FORM. PRICE, ETC. 29 ANN CODE Fo~r N4IA U S, DEPARTMENT OF COMMERCE (REV. 1-73) NATIONAL TECHNICAL. INFORMATION SERVICE VsC 0mm-Dc 13%34.P73 DOCUMENT TRAVELER N7 4-14 891 OPTIMIZATION IN THE DESIGN OF A 12 GIGAHERTZ LOW COST GROUND RECEIVING SYSTEM FOR BROADCAST SATELLITES, VO7L1TjE VOLUME II K. Ohkubo, et al Stanford University Stanford, California October 1972 DISTRIBUTED BY: National Technical Information Service U.S. DEPARTMENT OF COMMERCE 5285 Port Royal Road, Springfield Va. 22151 NASA CR-121184 VbI­ SU-SEL-72-043 .' '. H m I "4s=Wt H Tc, H t'* ~r Oub I GROUND RECEIVING SYSTEM FOR BROADCAST SATELLITES DWPd 0 1 Volume II P W ' thtoW Antenna System and Interference by r t+ I''1- LO0WL2 0H K. Ohkubo, C. C. Han, J. Albernaz, J. M. Janky, and B. B. Lusignan H H a ,-J Ntis: - W tl1- Center for Radar Astronomy Stanford University Stanford, California -4 Q prepared for NATIONAL AERONAUTICS AND SPACE ADMINISTRATION ;M 0 NASA Lewis Research Center 00 Contract NAS 3-14362 Dr. E. F. Miller, NASA Technical Monitor Reproduced by NATIONAL TECHNICAL INFORMATION SERVICE f Commerce U'SSpngfield, Dopardm0n0 VA. 22151 NASA CR-121184 SU-SEL-72-043 Final Report OPTIMIZATION IN THE DESIGN OF A 12 GIGAHERTZ LOW COST GROUND RECEIVING SYSTEM FOR BROADCAST SATELLITES Volume II Antenna System and Interference by K. Ohkubo, C. C. Han, J. Albernaz, J. M. Janky, and B. B. Lusignan Center for Radar Astronomy Stanford University Stanford, California 94305 prepared for NATIONAL AERONAUTICS AND SPACE ADMINISTRATION October 15, 1972 Contract NAS 3-14362 NASA Lewis Research Center Cleveland, Ohio Dr. E. F. Miller, NASA Technical Monitor J TABLE OF CONTENTS 1. INTRODUCTION .... ...... 1 1.1 Background .... ..... ... ......... 1 1.2 Objective and Scope of Research.......... 6 2. ANTENNA SYSTEM ANALYSIS... •............ 9 2.1 Introduction ................ ...... 9 2.2 Antenna Gain and Efficiency......... .. .I..10 2.3 Off-Axis Gain Optimization. ................. 13 2.4 Noise Temperature..................... 18 2.4.1 Antenna Noise Temperature .......... 18 2.4.2 System Noise Temperature. .......... 20 2.h.3 Figure-Of-Merit (G/Ts).. .......... 22 2.5 Antenna Categories ....... ........... 23 2.6 Antenna Feed .... ...... ........... 26 2.7 Image Rejection Filter . ............. 31 2.8 Tracking Requirements .............. .... 32 3. EFFECT OF GROUND ANTENNA CHARACTERISTICS ON SATELLITE SPACING .............. ........... ... .. 39 3.1 Introduction ........ ........... .... 39 3.2 Interference Objective and Protection Ratio...... 4o PK-j!" G PAGE BLANK NOT FILMED iii TABLE OF CONTENTS (CONT'D) Page 3.2.1 Protection Ratio of An FM Television System....... ................. 41 3.2.2 Protection Ratio of a Communication Satellite FM Telephone System .. ......... ... .. 44 3.3 Effect of Earth Station Antenna on RF Interference 46 3.3.1 Down-Link Interference - Satellites To Earth Station .......... .... .. 46 3.3.2 Up-Link Interference-Earth Stations To Satellite ........... ....... 48 3.4 Reduction of Near-In Sidelobes in the Synchronous Equatorial Orbit Direction .. ........ ...... 50 3.4.1 Review of Sidelobe Suppression Techniques for a Reflector Type Antenna.......... .. 50 3.4.2 Use of an Absorber Array in Sidelobe Suppression ....... ............ .. .55 3.4.3 Experimental Investigation.... ........ 6 3.5 Antenna Pattern and Satellite Spacing.... ....... 74 3.6 Effect of Polarization Discrimination on Satellite Spacing........ ..................... 80 4. ZONED REFLECTOR ANTENNAS FOR A LOW COST SATELLITE GROUND STATION............ ............ ... 89 4.1 Introduction ....................... 89 4.2.1 Formulation . ... .......... .... 90 4.2.2 Gain and Efficiency Calculations . .... 93 iv TABLE OF CONTENTS (CONTD) Page 4.2.3 Design Example....... ............ 97 4.3 Stepped Cone-Section Reflector ..... ...... ...100 5. A MASS PRODUCIBLE 12 GHz ANTENNA FEED SUBSYSTEM- EXPERIMENTAL MODEL........... ............ ...107 5.1 Introduction ........... ............ ...107 5.2 Multimode Feed Horn.......... ............. 107 5.2.1 Sidelobe Suppression and Beam Equalization of Conical Horn Pattern Obtained by Using the TM Mode ............... ...... 110 5.2.2 Design Considerations. .......... .. 116 5-3 Circular Waveguide Polarizer . ........... 125 5.3.1 Parameters of a Polarizer .......... 126 5.5.2 General Analysis .... ............ 126 5.3.3 Experimental Results.............. 129 5.4 Waveguide High-Pass Filter With Exponential-Raised­ To-Cosine Taper........ ......... ........ 132 5.4.1 Specification of the Profile of a Waveguide Taper by the Use of Numerical Technique . 133 5.4.2 Experimental Results .... ............ 140 5-5 12 GHz Antenna System Performance Sunnary.... .... 145 5.5.1 Frequency Range ...... .............. 145 5.5.2 Efficiency....... ............ .... 1145 5.5.4 Noise Temperature and G/TS . .. .. 147 V TABLE OF CONTENTS (CONT'D) Page 6. COST ANALYSIS OF SATELLITE GROUND STATION .. ....... ... 149 6.1 Economic Parameters of a Satellite Communication Ground Station ................. 149 6.2 Reflector Cost . .i............... 151 6.3 Installation Cost................ .... 155 6.4 Cost of Antenna Feed System. ............ 155 6.5 Cost of Tracking System. .............. 156 6.6 Antenna Cost .................. .... 161 6.7 Cost Optimization of a Ground Station. ....... 161 7. CONCLUSIONS ... .... ............ ........ 165 APPENDIX A: Mode Conversion in a Circular Waveguide By a Step Discontinuity ....... ............ 169 APPENDIX B: Impedance and Reflection Coefficient of a Nonuniform Waveguide ..... .......... ... 173 REFERENCES.......... .............. ... .... 177 vi LIST OF FIGURES Figure Page (2-1) Illustration of off-axis gain variations. .. ..... 15 (2-2) On-axis gain of an 8-foot reflector with multimode feed ............. ............. ..... 17 (2-3) Off-axis (± 0.30) gain of an 8-foot reflector with multimode feed........ ........... ....... 17 (2-4) Sky noise temperature ... ...... ........ 21 (2-5) Ground noise temperature ....... .......... 21 (2-6) Receiver noise temperature vs noise figure. ...... 22 (2-7) Comparison of Oassegrain and prime-focus system . 25 (2-8) Gain reduction due to feed tilt .......... .... 53 (2-9) Basic block diagram of a step-track system...... 35 (3-1) Protection ratio of FM TV system . ... ........ 43 (3-2) Down-link interference geometry ........ ..... 48 (5-3) Up-link interference geometry.. ........... 50 (3-4) Antenna configuration for aperture blockage com­ pensation .......... .............. ... 52 (5-5) Suppression of near-in sidelobes by aperture blockage compensation........ ........... ... .... 52 (3-6) Antenna configuration for active zone sidelobe cancellation .......... ............. .. ... 54 (3-7) Suppression of near-in sidelobes by active zone cancellation....... .................. ... 54 (5-8) Coordinate system ....... ............. ... 55 (5-9) Absorber array at the aperture of reflector..... 56 vii LIST OF FIGURES (CONTD) Figure Page (3-10) Absorber array radiation patterns ........ ..... 59 (3-11) Illustration of matching sidelobe structure -- uniform illumination................. ........ 6o (3-12) Radiation pattern resulting from sidelobe cancellation -- uniform illumination ............. .... 60 (3-13) Two-dimension radiation contours -- uniform illumin­ ation .................... ......... 61 (3-14) Illustration-of matching sidelobe structure -­ tapered illumination.............. ...... 63 (3-15) Radiation pattern resulting from sidelobe cancellation-­ tapered illumination.............. ...... 63 (3-16) Two-dimension radiation contours -- tapered illumination............ ........... 64 (3-17) Features of experimental reflector ... ...... ... 66 (3-18) Reflector with absorbers mounted .... .......... 66 (3-19) Antenna range ... ....................... 67 (3-20) Test set-up for pattern measurements............. 68 (3-21) Measured radiation patterns of a reflector -- with and without absorber........ ............. 70 (3-22) Measured radiation patterns of a reflector -- with and without absorber........ ........ ...... 70 (3-23) Measured radiation patterns of a reflector -- with and without absorber........ ........ ...... 71 viii LIST OF FIGURES (CONT'D) Figure Page (3-24) Measured radiation patterns of a reflector -- with and without absorber... ............ ...... 71 (3-25) Measured radiation patterns of a reflector -- with and without absorber ... ............ ...... 72 (3-26) Measured radiation patterns of a reflector -- with and without absorber.... ................ 72 (3-27) Measured radiation
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