Design and Analysis of Leakywave Antennas for Novel Functionalities
Date
2021
Authors
R, Karthik.
Journal Title
Journal ISSN
Volume Title
Publisher
National Institute of Technology Karnataka, Surathkal
Abstract
This thesisdealswiththeeffectivedesignofplanarleakywaveantennas(LWA)for
novelfunctionalities.Theworkdescribesamethodologybasedonsingle-layertrans-
mission basedGoubaulineandinvestigationofasymmetryinHalf-modesubstratein-
tegratedwaveguide(HMSIW)periodicLWAstoaddressverydifferentantennaconfig-
urations. FournovelLWAsareproposedtoachievewideanglebeamscanning,single
layer basedEnd-Fireradiation,dual-bandandsimultaneousdual-beamscanningfunc-
tionalities.
WidebeamscanningisdesignedusingGoubauline.Incontrasttotheconventional
LWAwithasmallscanninganglerangeandlowefficiency,thisworkemployedape-
riodically bendingGoubauline,whichnotonlybringsinaperiodicperturbationfor
leakywaveradiation,butalsoenhancesthescanningrangeduetotheincreaseddelay
for eachlineelement.Theproposedantennafeaturesgoodradiationperformanceand
has acompactandlowprofileconfiguration.Also,asimpleandlow-profilePlanar
Goubau linebasedEndfireantennaisdesigned.Endfireradiationisachievedbymod-
ifying theGoubaulineintoinvertedperiodicarrangementofV-shapedunitcells.The
proposed endfireantennahasasinglemetalliclayerwithasimpleconfigurationwhich
is easytofabricateandalsoeasytointegratewithotherelectronicscircuits.
Most oftheexistingLWAsaregenerallydesignedforasinglebandapplication.In
this work,byetchingsimplespiraltypeslotsontheHMSIWcavity,anoveldual-band
dual-polarized LWAisdesigned.Theantennaradiatesthelinearlypolarized(LP)wave
in thelowerbandandcircularlypolarizedwaveinthehigheroperatingband.Inthe
higher operatingbandantennaexhibitsbothright-handcircularpolarization(RHCP)
as wellasthelefthand(LHCP)circularpolarizationinthenearmainbeamdirection.
Also, asymmetryisinvestigatedinHMSIWLWA.Basedonasymmetry,twodifferent
configurations ofdual-bandLWAsaredesigned.ThefirstconfigurationradiatesLP
v
wavesinthelowerbandandCPwavesintheupperbandwhentheunitcellsarecas-
caded sequentially.Thesecondconfiguration,wherethesidewallviaoftheHMSIW
unit cellsareconnectedalternatingly,providessimultaneousdual-beamswithdiffer-
ent polarizationintheupperoperationalbandinadditiontotheLPbeaminthelower
operational band.ThesenovelfunctionalitiesofLWAcanbeeffectivelyusedformulti-
objectivetrackingapplicationsandforenhancingthechannelcapacityofautomotive
and satellite-basedwirelesscommunicationsystems.Sincebothantennaconfigurations
had dualfrequencybandswithdifferentpointingdirectionsinscanning,itcanalsobe
useful forvehicularapplicationstotrackdifferentobjectsinitsnearbylocations
Proposed designsarefabricatedusingLPKFprotomatmachineS103andexperi-
mentally verifiedusingradiationpatternmeasurementset-up.Impedancebandwidth,
peak gain,axialratiobandwidthandradiationefficiencyaremeasuredandcompared
with thesimulatedresults.Theperformanceoftheproposedworksarecomparedwith
the previousliterature.
Description
Keywords
Department of Electronics and Communication Engineering, Leaky Wave Antenna, Goubau Line, Circular Polarization, Half Mode Substrate Integrated Waveguide