Metamaterials, mmWave antennas, 3D radar and ...

Metamaterials are engineered/manmade materials with properties not found in nature. Antenna designs based on metamaterials can significantly ... SkiptoprimarynavigationSkiptomaincontentSkiptoprimarysidebarSkiptofooter Wirelesscommunication,5GmmWavedevices,spacecommunications,GPS,satellites,spacevehiclenavigation,automobiles,andairplanesarejustsomeapplicationsformetamaterialantennas.Metamaterialsareengineered/manmadematerialswithpropertiesnotfoundinnature.Antennadesignsbasedonmetamaterialscansignificantlyincreasetheradiatedpower.Thelatestmetamaterialantennadesignscanradiateupto95%oftheinputradiosignal. Conventionalantennasneedtobeatleasthalfthesizeofthesignalwavelengthtooperateefficiently.At300MHz,forinstance,anantennawouldneedtobehalfameterlong.Incontrast,experimentalmetamaterialantennasareassmallasone-fiftiethofawavelengthandcouldhavefurtherdecreasedinsize.Somemetamaterialantennasarealreadycommerciallyavailable.ThisFAQwillbrieflyreviewsomeofthecurrently-availablemetamaterialantennadesigns,includingfractalantennas,electronically-scannedmetamaterialantennas,andholographicbeamforming,startingwithhigh-resolutionradarforautomotiveanddefensesystems. ThisZantennatestedattheNationalInstituteofStandardsandTechnologyissmallerthanastandardantennawithcomparableproperties.Itshighefficiencyisderivedfromthetiny“Zelement”inthecenterofthesquarethatactsasametamaterial,greatlyboostingtheradiatedsignal.Thesquareis30millimetersonaside.(Image:Wikipedia) Metamaterial-basedantennaswillofferhigherperformancelevelsbeyondtherestrictiveefficiency-bandwidthlimitsofconventionallyconstructedantennas.Metamaterialsenableminiatureantennaswithhighgainsincetheradiatingelementscanbecombinedintolargerarrays.Inaddition,thenegativerefractiveindexofmetamaterialscanresultinfocusedelectromagneticradiationratherthandispersedradiation. 3Dradarandscannedarrays Metamaterialelectronicallyscannedarray(MESA)radarcanbereducedfromvehicle-mountedsystemstoapaperbackbook’ssizewithacomparablereductionincost.SomeoftheseradarscanbemanufacturedwithstandardPCBfabricationtechnologyandbeusedinavarietyofnewapplicationswheretoday’sconventionalelectronically-scannedarray(ESA)radarsaretoolargeandtooexpensive.Thesecost/performanceattributesopenupapplicationsforMESAsindronesandotherunmannedaerialvehicles,autonomousgroundvehicles(includingautomobiles),portablesecuritysystems,andforcounteringthreatsfromunmannedairsystems(UAS),includingcomplexenvironmentswithdrones,cruisemissiles,aircraft,andballisticmissiles. SomeMESAradarsincludesoftware-definedradartechnologyand3Delectronicbeamsteering.Forexample,one77GHzMESAradarwithbeamsteeringcanaccuratelydeterminetherangeandspeedofobjects;italsohassufficientresolutiontoenableartificialintelligencetoclassifyandinterpretthesurroundingenvironmentwithhighprecision. Metamaterialelectronicallyscannedarray(MESA)radarsoffersignificantsize,weight,power,andcostadvantagesovertraditionalESAradarandcanbefabricatedusingstandardPCBfabricationandassemblytechniques.(Image:Echodyne) MetamaterialsformmWaveantennas Innaturalmaterials,propertiessuchasmagneticpermeabilityandelectricpermittivityaredeterminedbyatomsandmolecules’responsetotheelectromagneticwavepassingthroughthem.Butinmetamaterials,thesepropertiesaredeterminedbytheperiodicarrangementofscatteringstructuressmallerthanthewavelengthoftheelectromagneticwavestheyareinteractingwith. Thesesmallstructuresarefabricatedfromconventionalmaterialssuchasmetalsandplastics.Still,theirsize,shape,orientation,andconfigurationcanbedesignedtointeractwithelectromagneticwavestocreatefinelytunedresonancesandotherunconventionalpropertiesincertainfrequencybands.Thesespecialpropertiescanbeusedforawidevarietyofapplications,forexample,toenhancetheefficiencyanddirectivityofmicrowaveantennas. Arecently-developedelectronically-scannedantennatechnology,calledmetamaterialsurfaceantennatechnology(MSAT),isbasedonadiffractivemetamaterialsconceptandachieveselectronicscanningusinghigh-birefringenceliquidcrystals(LCs).Theseantennasprovidehighreliability,lowpowerconsumption,andhighdatathroughputforbroadbandInternetconnectivityonmovingvehiclesorfixedinstallations.MSAT’slowpowerconsumptionallowsittoleverageexistingpoweronmobileplatforms,reducingintegrationcomplexity. TheuseofLCmaterialsasatunabledielectricatmmWavefrequenciespermitsover60°beamscanningwithunder10Wofpowerconsumptionandanantennathicknessofabout5cmwithnomovingparts.Asnoted,anMSATusesadiffractivemetasurface,ratherthanarefractiveone,toholographicallydefinetheantennabeam.Theabilitytoindividuallytuneeachantennaelement’sresonancefrequencytocreateadynamicallyreconfigurablediffractiongratingenablestheimplementationoftheholographicdesign. Metamaterialsurfaceantennatechnologyfor5Gapplicationsisbasedontheuseofhigh-birefringenceliquidcrystals.(Image:Kymeta) Metasurfaceantennashavebeenfabricatedbyprintinghundredsorthousandsofelementsintoanarray.Thearrayisplacednexttoarectangularwaveguidefeedthatcouplesthearraytoasingletransmitter.Computercontrolisusedtotunetheelementstoresonateataspecificfrequencyandradiatetheguidewave.Thearray’sphysicalstructureisdesignedsothattheradiatedwavesarecoherent(in-phase)attheprogrammedscanangleoftheantennabeam.Theamountofenergyisthesumofthewavesradiatedbytheindividualelements.Theelementsthatareoutofphasedonotcontributetothesignal.Thescanangleistheanglebetweenthebeamandanaxisperpendiculartothetopofthemetasurfaceantenna. Holographicbeamforming Holographicbeamformingalsoshapestheantenna’sradiopatternundersoftwarecontrolwithouttheneedtophysicallychangeorreconfiguretheantenna.Itcanbeconsideredtobeasoftware-definedantenna. Conventionalphasedarraysneedbulkyandexpensivephaseshifterstocontrolantennabeamsdynamically.MIMOsystems,inwhichtwoormoretransmittersandreceiverscoordinatetobeamsignalsintomultipledevices,requirepower-hungrydigitalsignalprocessors.Newmetamaterial-basedholographicbeamformingantennasusesimpleswitchedcontrolantennaelementscontrolledbyFETs,resultinginthinnerantennaswithlowercost,lighterweight,andlowerpowerconsumption. 14GHzholographicbeamformingantennamadeusingmetamaterials.Thesemetamaterialsantennascanbeproducedtooperatebetween1and70GHzandproducehighly-focusedbeams.(Image:Pivotal) Holographicantennasareexpectedtooperatefromabout500MHzto60GHz.Signalscantravelfurtherwithhighergainusingholographicbeamforming.Inthecaseof5Gnetworks,thatmeansthatthemmWavesinthehigherfrequencybandswillnotbeblockedaseasilybybuildingsandcouldtravelfartherthanafewkilometers.Asaresult,holographicbeamformingantennasboostthroughputforcellularnetworksandpossiblyreplacefiberopticcablesasbackhaullinksbetweenbasestations. OneformofmetamaterialholographicantennasconsistsofaflexiblePCBcoveredinmetalcellssmallerthanthewavelengthoftheradiowavesbeingcontrolled.Thecontrolsoftwareactivatesvariousantennaelementstocreatebeamsofradiowaves.Achangingdcbiasisusedtochangetheantenna’sproperties,whichcanswitchthecontrolledelementsinamicrosecond.Thismethodofcontrolenablesthesamespectrumbandtobesequentiallydirectedinmultipledirections,allowingthesamespectrumbandtobeusedbymultiplebeamsatthesametime.Inaddition,theantennassuppressside-lobesthatcouldresultininterference,improvingspectralefficiency(theamountofdatathatcanbesenttoagivennumberofdevicessimultaneously). TheseriesofFAQsincludesbothcurrentcommercialexamplesandresearchanddevelopmentactivitiesrelatedtometamaterials.YoumightalsobeinterestedinreadingthefirstFAQinthisseries,“Metamaterials’potentialfortransformingelectronics.”ThenextFAQwilldiveinto“Metamaterialsforpowerandenergy.” References Metamaterialantenna,Wikipedia Metamaterial-surfaceflat-panelantennatechnology,Kymeta Reducing5GDeploymentCostsUsingHolographicBeamFormingRepeaters,PivotalCommware Youmayalsolike: Metamaterialsforpowerandenergy Metamaterials’potentialfortransformingelectronics mmWaveantennasandantennamanagementfor5G What isthe5GRF/mmWavesignalchain? BasicsofmmWaveanditsapplications Themicrostripantenna,Part1:Basics PrimarySidebarSearchthiswebsite Subscribetoweeklyindustrynews,newproductinnovationsandmore. 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