Analysis of constant phase contours of evaporation duct mode functions for waveguide mode propagation.

112 Pages·0.76 MB·en_US

by  Che, Jen-Peng.;Lee, Hung-Mou.

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11.TITLE(IncludeSecurityClassification)
ANALYSISOFCONSTANTPHASECONTOURSOFEVAPORATIONDUCTMODEFUNCTIONSFORWAVEGUIDEMODE
PROPAGATION
12.personalauthor(S) Jen-PengChe
13a.TYPEOFREPORT 13b.TIMECOVERED 14.DATEOFREPORT(year,month,day) 15.PAGECOUNT
Master'sThesis From To September1992 101
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17.COSATICODES 18.SUBJECTTERMS(continueonreverseifnecessaryandidentifybyblocknumber)
SUBGROUP EvaporationDuct,WaveguideModePropagation
19.ABSTRACT(continueonreverseifnecessaryandidentifybyblocknumber)
TheM-LayerprogramtrackstheconstantphaselinesIm{D(q)} = andlooksfortheir
intersectionswiththelinesRe{D(q)} = forthelocationsofthezerosofthemodefunctionD(q).
Thesetwotypesofconstantphaselinesaretrackedandplottedoverasearchregionwhich
containsmodeshavingarangeattenuationrateofnomorethan 5dBperkm.Severalnew
parametersforuseinmodesearcharededucedfromtheresultsandsomeoldonesareverified.
Futurestudiesinwaveguidemodepropagationtheorypertainingtoatmosphericductsmay
benefitfromthiswork.Animprovedmodesearchstrategyisalsoproposed.
T257770
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Hung-MouLee [phone] EC/Lh
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ANALYSIS OF CONSTANT PHASE CONTOURS OF
EVAPORATION DUCTMODE FUNCTIONS
FOR WAVEGUIDE MODE PROPAGATION
by
Jen-Peng Che
Lieutenant Commander, Taiwan Navy
B.S., Chinese Naval Academy, 1980
Submitted in partial fulfillment
oftherequirements forthe degree of
MASTER OF SCIENCE IN ELECTRICAL ENGINEERING
from the
NAVAL POSTGRADUATE SCHOOL
September 1992
ABSTRACT
TheM-LayerprogramtrackstheconstantphaselinesIm{D(q)} = andlooksfor
theirintersections withthelines Re{D(q)} = forthe locations ofthe zerosofthe mode
function D(q). These two types of constant phase lines are tracked and plotted over a
searchregionwhichcontainsmodeshavingarangeattenuationrateofnomorethan5 dB
perkm. Severalnewparametersforuseinmode searcharededucedfromtheresults and
some old ones are verified. Future studies in waveguide mode propagation theory
pertaining to atmospheric ducts may benefit from this work. An improved mode search
strategy is also proposed.
TABLE OFCONTENTS
INTRODUCTION
I. 1
A. THE WAVEGUIDE MODE THEORY OF PROPAGATION 2
B. MODE SEARCH PRINCIPLE 7
n. MODE FUNCTION IN THE COMPLEXqn/t1 PLANE . 11
A. MODE LOCATIONS 11
B. PHASE LINE TRACKING 13
1. Downward Tracking 13
2. Upward Tracking 18
IE. ANALYSIS AND CONCLUSIONS 21
A. MODE SEARCH PARAMETERS 21
B. MODE SEARCH STRATEGY 24
1. TrackTermination 24
2. Search Termination 25
3. Track Duplication Avoidance 27
q^
APPENDDC A: MODE LOCATIONS INTHE COMPLEX PLANE 28
IV