Xa kufikwa kuiimpondo, umbuzo abantu abaxhalabele kakhulu ngawo "Ifumaneka njani i-radiation ngokwenene?"Ingaba intsimi ye-electromagnetic eveliswa ngumthombo wesignali isasazeka njani ngentambo yothumelo nangaphakathi kwe-eriyali, kwaye ekugqibeleni "yahlula" kwi-eriyali ukwenza i-wave yesithuba sasimahla.
1. Imitha yocingo olunye
Masicinge ukuba ingxinano yentlawulo, echazwe njenge-qv (Coulomb/m3), isasazwe ngokufanayo kucingo olusetyhula kunye nommandla onqamlezayo we-a kunye nomthamo we-V, njengoko kubonisiwe kuMfanekiso 1.
Umfanekiso woku-1
Intlawulo epheleleyo ye-Q kumthamo we-V ihamba kwicala le-z kwi-uniform speed Vz (m/s).Kunokungqinwa ukuba uxinaniso lwangoku lwe-Jz kwicandelo lomnqamlezo wocingo lu:
Jz = qv vz (1)
Ukuba ucingo lwenziwe ngomqhubi ofanelekileyo, uxinaniso lwangoku lweJs kumphezulu wocingo lu:
Js = qs vz (2)
Apho qs kukuxinana kwentlawulo yomphezulu.Ukuba ucingo lubhityile kakhulu (ngokufanelekileyo, iradiyasi ngu-0), okwangoku kucingo kunokubonakaliswa ngolu hlobo:
Iz = ql vz (3)
Apho i-ql (coulomb/imitha) intlawulo ngobude beyunithi nganye.
Sizixhalabele kakhulu ngeengcingo ezibhityileyo, kwaye izigqibo zisebenza kula matyala mathathu angasentla.Ukuba umsinga uyatshintsha-tshintsha ixesha, i-derivative ye-formula (3) ngokumalunga nexesha ihamba ngolu hlobo lulandelayo:
(4)
i-az kukukhawuleza kwentlawulo.Ukuba ubude bocingo ngu-l, (4) bunokubhalwa ngolu hlobo lulandelayo:
(5)
I-Equation (5) lubudlelwane obusisiseko phakathi kwangoku kunye nentlawulo, kunye nobudlelwane obusisiseko bemitha ye-electromagnetic.Ukubeka nje, ukuvelisa i-radiation, kufuneka kubekho i-current-yant-yant current okanye i-acceleration (okanye i-deceleration) yentlawulo.Sidla ngokukhankanya izicelo ezikhoyo kwixesha le-harmonic, kwaye intlawulo idla ngokukhankanywa kwizicelo zexeshana.Ukuze uvelise ukukhawuleza kwentlawulo (okanye ukuncipha), ucingo kufuneka lugobe, lugoqwe kwaye luyeke.Xa umrhumo oscillates ngexesha-harmonic motion, iya kuvelisa ukukhawulezisa intlawulo ngamaxesha (okanye deceleration) okanye ixesha-yahluka langoku.Ngoko ke:
I-1) Ukuba intlawulo ayihambi, akuyi kubakho okwangoku kwaye akukho mitha.
2) Ukuba intlawulo ihamba ngesantya esingaguqukiyo:
a.Ukuba ucingo luthe tye kwaye alunasiphelo ngobude, akukho mitha.
b.Ukuba ucingo lugobile, lugobile, okanye luyayeka, njengoko kuboniswe kuMzobo 2, kukho imisebe.
3) Ukuba intlawulo i-oscillates ngexesha, intlawulo iya kukhupha nangona ucingo luthe tye.
Umfanekiso wesi-2
Ukuqonda okusemgangathweni kwendlela yokusasazeka kwemitha kunokufumaneka ngokujonga umthombo we-pulsed oqhagamshelwe kucingo oluvulekileyo olunokuthi lubekwe phantsi ngomthwalo ekupheleni kwawo ovulekileyo, njengoko kubonisiwe kuMfanekiso 2 (d).Xa ucingo luqala amandla, iintlawulo (ii-electron zamahhala) kwi-wire zisekwe kwimizila yombane eveliswa ngumthombo.Njengoko iintlawulo zikhawuleziswa ekupheleni komthombo wocingo kwaye zincitshiswe (i-acceleration engalunganga ngokumalunga nesindululo sokuqala) xa ibonakaliswe ekupheleni kwayo, intsimi ye-radiation yenziwa ekupheleni kwayo kunye nakulo lonke ucingo.Ukukhawuleziswa kweentlawulo kufezekiswa ngumthombo wamandla wangaphandle obeka iintlawulo kwintshukumo kwaye uvelise ibala lemitha elihambelanayo.Ukuncitshiswa kweentlawulo eziphelweni zocingo kufezwa yimikhosi yangaphakathi ehambelana nentsimi ebangelwayo, ebangelwa ukuqokelela kweentlawulo ezigxininisiweyo ekupheleni kocingo.Imikhosi yangaphakathi ifumana amandla ekuqokeleleni intlawulo njengoko isantya sayo sincipha ukuya ku-zero ekupheleni kocingo.Ke ngoko, ukukhawuleziswa kweentlawulo ngenxa yokutsalwa kwentsimi yombane kunye nokuthotywa kweentlawulo ngenxa yokungaqhubeki okanye ijika eligudileyo le-impedance yocingo ziindlela zokwenziwa kwemitha ye-electromagnetic radiation.Nangona zombini uxinano lwangoku (Jc) kunye noxinaniso lwentlawulo (qv) ziziimeko zentsusa kwiiequations zikaMaxwell, intlawulo ithathwa njengeyona nto ibalulekileyo, ngakumbi kwiinkalo ezidlulayo.Nangona le ngcaciso yotshiso lwemitha isetyenziswa ikakhulu kumazwe adlulayo, inokuphinda isetyenziswe ukuchaza imitha yemo ezinzileyo.
Cebisa ezininzi ezibalaseleyoiimveliso ze-eriyaliyenziwe nguRFMISO:
RM-TCR406.4
RM-BCA082-4(0.8-2GHz)
RM-SWA910-22(9-10GHz)
2. Imitha yocingo ezimbini
Xhuma umthombo we-voltage kumgca wokuhanjiswa kwee-conductor ezimbini eziqhagamshelwe kwi-antenna, njengoko kubonisiwe kuMfanekiso 3 (a).Ukusebenzisa i-voltage kumgca we-wire-wire kuvelisa indawo yombane phakathi kwabaqhubi.Imigca yentsimi yombane isebenza kwii-electron ezikhululekile (zihlulwe ngokulula kwii-athomu) eziqhagamshelwe kumqhubi ngamnye kwaye zinyanzelise ukuba zihambe.Ukuhamba kweentlawulo kuvelisa i-current, ethi ivelise i-magnetic field.
Umfanekiso wesi-3
Samkele ukuba iintambo zombane ziqala ngeentlawulo ezilungileyo kwaye ziphele ngeentlawulo ezingalunganga.Ewe kunjalo, banokuqala ngeentlawulo ezilungileyo kwaye baphele ngokungenasiphelo;okanye uqale ngokungenasiphelo kwaye uphele ngeentlawulo ezimbi;okanye zenze iilophu ezivaliweyo ezingaqalisi okanye zingapheli nazo naziphi na iintlawulo.Imigca yemagnethi isoloko isenza amarhintyela avaliweyo ajikeleze abaqhubi abaphetheyo ngoku kuba akukho ntlawulo yamagnetic kwifiziksi.Kwezinye iifomyula zemathematika, umrhumo olinganayo wemagnethi kunye nemisinga yemagnethi ziyaziswa ukubonisa ubumbini phakathi kwezisombululo ezibandakanya amandla kunye nemithombo yemagnethi.
Imigca yendawo yombane ezotywe phakathi kwabaqhubi ababini inceda ukubonisa ukuhanjiswa kwentlawulo.Ukuba sicinga ukuba umthombo we-voltage sinusoidal, silindele ukuba indawo yombane phakathi kwabaqhubi nayo ibe sinusoidal kunye nexesha elilingana nelo lomthombo.Ubungakanani obunxulumene namandla ombane abonakaliswe kukuxinana kwemigca yendawo yombane, kwaye iintolo zibonisa ulwalathiso oluhambelanayo (olulungileyo okanye olubi).Ukuveliswa kwexesha elitshintshayo lombane kunye nemagnethi phakathi kwee-conductor zenza i-electromagnetic wave esasaza kumgca wothumelo, njengoko kuboniswe kuMfanekiso 3 (a).I-electromagnetic wave ingena kwi-eriyali kunye nentlawulo kunye nomsinga ohambelanayo.Ukuba sisusa inxalenye yesakhiwo se-antenna, njengoko kuboniswe kwi-Figure 3 (b), i-wave ye-free-space wave inokuqulunqwa ngokuthi "ukudibanisa" iziphelo ezivulekileyo zemigca yendawo yombane (eboniswe yimigca echokoziweyo).I-wave ye-free-space iphinda iphindwe, kodwa i-phase-phase point P0 ihamba ngaphandle ngesantya sokukhanya kwaye ihamba umgama we-λ/2 (ukuya kwi-P1) kwisiqingatha sexesha.Kufuphi ne-eriyali, inqanaba le-P0 lihamba ngokukhawuleza kunesantya sokukhanya kwaye lisondela kwisantya sokukhanya kwiindawo ezikude ne-eriyali.Umzobo we-4 ubonisa ukuhanjiswa kwebala lombane elikhululekileyo λ∕2 i-eriyali kwi-t = 0, t/8, t/4, kunye ne-3T/8.
Umzobo 4 Isithuba sasimahla sosasazo lwendawo yombane ye-λ∕2 i-eriyali e-t = 0, t/8, t/4 kunye ne-3T/8
Ayaziwa ukuba amaza akhokelwayo ahlukaniswe njani kwi-antenna kwaye ekugqibeleni aqulunqwe ukuba asasazeke kwindawo ekhululekile.Sinokuthelekisa amaza eendawo ezikhokelwayo nezikhululekileyo namaza amanzi, anokubangelwa lilitye eliwiswe kumanzi azolileyo okanye ngezinye iindlela.Emva kokuba ukuphazamiseka emanzini kuqala, amaza amanzi aveliswa kwaye aqala ukusabalalisa ngaphandle.Nokuba uphazamiseko luyayeka, amaza akayeki kodwa aqhubeke esasaza phambili.Ukuba ukuphazamiseka kuyaqhubeka, amaza amatsha ahlala eveliswa, kwaye ukusasazwa kwala maza kuncipha emva kwamanye amaza.
Kukwanjalo nakumaza e-electromagnetic waveliswa kukuphazamiseka kombane.Ukuba ukuphazamiseka kokuqala kombane okuvela kumthombo kungokwexesha elifutshane, amaza ombane aveliswe asasazeke ngaphakathi kumgca wothumelo, emva koko faka i-eriyali, kwaye ekugqibeleni uphume njengamaza asimahla, nangona uvuselelo lungasekho (njengamaza amanzi. kunye nokuphazamiseka abakwenzileyo).Ukuba ukuphazamiseka kombane kuqhubeka, amaza e-electromagnetic akhona ngokuqhubekayo kwaye alandele ngokusondeleyo emva kwawo ngexesha lokusasaza, njengoko kuboniswe kwi-antenna ye-biconical eboniswe kuMzobo 5. Xa amaza ombane e-electromagnetic engaphakathi kwimigca yokuhambisa kunye nee-antenna, ubukho babo buhambelana nobukho bombane. intlawulo ngaphakathi komqhubi.Nangona kunjalo, xa amaza esasazwa, enza i-loop evaliweyo kwaye akukho ntlawulo yokugcina ubukho bawo.Oku kusikhokelela kwisigqibo sokuba:
Ukutshatyalaliswa kwentsimi kufuna ukukhawuleza kunye nokunciphisa intlawulo, kodwa ukugcinwa kwentsimi akudingi ukukhawuleza kunye nokunciphisa intlawulo.
Umfanekiso wesi-5
3. I-Dipole Radiation
Sizama ukucacisa indlela apho imigca yentsimi yombane iqhawula khona kwi-antenna kwaye yenze amaza akhululekileyo, kwaye uthathe i-antenna ye-dipole njengomzekelo.Nangona iyingcaciso eyenziwe lula, ikwavumela abantu ukuba babone intuitively isizukulwana samaza asimahla.Umzobo we-6 (a) ubonisa imigca yendawo yombane eyenziwe phakathi kweengalo ezimbini ze-dipole xa imigca yombane iphuma ngaphandle nge-λ∕4 kwikota yokuqala yomjikelezo.Kulo mzekelo, makhe sicinge ukuba inani lemigca yombane eyenziwe ngu-3. Kwikota elandelayo yomjikelo, imigca emithathu yasekuqaleni yombane ihambisa enye λ∕4 (inani elipheleleyo λ∕2 ukusuka kwindawo yokuqala), kwaye ukuxinana kwentlawulo kwi-conductor iqala ukuhla.Inokuthi ithathelwe ingqalelo ukuba yenziwe ngokungeniswa kweentlawulo ezichaseneyo, ezicima iintlawulo kumqhubi ekupheleni kwesiqingatha sokuqala somjikelezo.Imigca yendawo yombane eveliswa ziintlawulo ezichaseneyo ziyi-3 kwaye ihambisa umgama we-λ∕4, emelwe yimigca echokoziweyo kuMfanekiso 6 (b).
Isiphumo sokugqibela sesokuba kukho imigca emithathu ezantsi ebaleni lombane kumgama wokuqala λ∕4 kunye nenani elifanayo lemigca yombane ephezulu kumgama wesibini λ∕4.Ekubeni akukho ntlawulo yenetha kwi-antenna, imigca yentsimi yombane kufuneka iphoqeleke ukuba ihluke kumqhubi kwaye idibanise ndawonye ukwenza i-loop evaliweyo.Oku kuboniswe kuMfanekiso 6(c).Kwisiqingatha sesibini, inkqubo efanayo yomzimba ilandelwa, kodwa qaphela ukuba ulwalathiso luchasene.Emva koko, inkqubo iphinda iphindwe kwaye iqhubeke ngokungapheliyo, yenza ukuhanjiswa kombane okufana nomfanekiso we-4.
Umfanekiso wesi-6
Ukuze ufunde ngakumbi ngee-eriyali, nceda undwendwele:
Ixesha lokuposa: Jun-20-2024
