I-polarization ingenye yezici eziyisisekelo zama-antenna. Okokuqala sidinga ukuqonda i-polarization yamagagasi endiza. Ngemuva kwalokho singaxoxa ngezinhlobo eziyinhloko ze-polarization yama-antenna.
ukwahlukana okuqondile
Sizoqala ukuqonda ukuhlukaniswa kwegagasi le-electromagnetic lendiza.
Igagasi le-electromagnetic eliyi-planar (EM) linezici eziningana. Esokuqala ukuthi amandla ahamba ohlangothini olulodwa (akukho nsimu eshintshayo eziqondisweni ezimbili eziqondile). Okwesibili, insimu kagesi kanye nensimu yamagnetic kuqondile komunye nomunye futhi kuqondile komunye nomunye. Amasimu kagesi kanye namagnetic aqondile esiqondisweni sokusabalala kwamagagasi endiza. Isibonelo, cabanga ngensimu kagesi enemvamisa eyodwa (insimu ye-E) enikezwe yi-equation (1). Insimu yamagnetic ihamba esiqondisweni se-+z. Insimu kagesi iqondiswe esiqondisweni se-+x. Insimu yamagnetic isendleleni ye-+y.
Ku-equation (1), qaphela umbhalo: . Lena yi-vector yeyunithi (ivektha yobude), ethi iphuzu lensimu kagesi liseceleni kuka-x. Igagasi lendiza liboniswe ku-Figure 1.
isithombe 1. Ukumelwa kwesithombe sensimu kagesi ehamba ohlangothini lwe-+z.
I-Polarization iyisimo sokulandelela kanye nokusabalala (i-contour) yensimu kagesi. Isibonelo, cabanga nge-equation yensimu kagesi yamagagasi endiza (1). Sizobona indawo lapho insimu kagesi ingu-(X,Y,Z) = (0,0,0) njengomsebenzi wesikhathi. Ubukhulu bale nsimu budwetshwe kuMfanekiso 2, ngezikhathi eziningana ngesikhathi. Insimu iyanyakaza ngemvamisa "F".
isithombe 2. Bheka insimu kagesi (X, Y, Z) = (0,0,0) ngezikhathi ezahlukene.
Insimu kagesi ibonwa ekuqaleni, ijikeleza emuva naphambili ngobukhulu. Insimu kagesi ihlala ihambisana ne-x-axis ekhonjisiwe. Njengoba insimu kagesi igcinwa emgqeni owodwa, le nsimu ingashiwo ukuthi ihlukaniswe ngomugqa. Ngaphezu kwalokho, uma i-X-axis ihambisana nomhlabathi, le nsimu ichazwa nangokuthi ihlukaniswe ngokuvundlile. Uma insimu iqondiswe ku-Y-axis, igagasi lingashiwo ukuthi lihlukaniswe ngokuvundlile.
Amagagasi ahlukaniswe ngomugqa awadingi ukuqondiswa nge-axis evundlile noma eqondile. Isibonelo, igagasi lensimu kagesi elinomkhawulo olele emgqeni njengoba kuboniswe kuMfanekiso 3 nalo lingahlukaniswa ngomugqa.
isithombe 3. Ubukhulu bensimu kagesi yegagasi elihlukaniswe ngomugqa eline-engela.
Insimu kagesi kuMfanekiso 3 ingachazwa ngesibalo (2). Manje kukhona ingxenye ka-x no-y yensimu kagesi. Zombili izingxenye zilingana ngobukhulu.
Into eyodwa okufanele uyiqaphele nge-equation (2) yizinkambu ze-xy-component kanye ne-electronic esigabeni sesibili. Lokhu kusho ukuthi zombili izingxenye zine-amplitude efanayo ngaso sonke isikhathi.
ukwahlukana okujikelezayo
Manje ake sithi insimu kagesi yegagasi lendiza inikezwa nge-equation (3):
Kulesi simo, izakhi ze-X- kanye ne-Y zingaphandle kwama-degrees angu-90 esigabeni. Uma insimu ibhekwa njenge-(X, Y, Z) = (0,0,0) futhi njengakuqala, insimu kagesi ngokumelene nejika lesikhathi lizovela njengoba kuboniswe ngezansi kuMfanekiso 4.
Umfanekiso 4. Amandla ensimu kagesi (X, Y, Z) = (0,0,0) isizinda se-EQ. (3).
Insimu kagesi kuMfanekiso 4 ijikeleza ngendilinga. Lolu hlobo lwensimu luchazwa njengegagasi eliyindilinga eliyindilinga. Ukuze kube ne-polarization eyindilinga, kumele kuhlangatshezwane nezindinganiso ezilandelayo:
- Izinga elijwayelekile lokwehlukaniswa okujikelezayo
- Insimu kagesi kumele ibe nezingxenye ezimbili eziqondile (eziqondile).
- Izingxenye eziqondile zensimu kagesi kumele zibe ne-amplitudes elinganayo.
- Izingxenye ze-quadrature kumele zibe ngama-degree angu-90 ngaphandle kwesigaba.
Uma uhamba esikrinini se-Wave Figure 4, ukujikeleza kwensimu kuthiwa kuphambene newashi kanye ne-RHCP ejikelezayo ngesandla sokudla. Uma insimu ijikeleziswa ngendlela yewashi, insimu izoba yi-LHCP ejikelezayo ngesandla sobunxele.
Ukwehlukaniswa kwe-elliptical
Uma insimu kagesi inezingxenye ezimbili eziqondile, ezingama-degree angu-90 ngaphandle kwesigaba kodwa zilingana ngobukhulu, insimu izohlukaniswa nge-elliptically. Uma ucabangela insimu kagesi yegagasi lendiza elihamba ohlangothini lwe-+z, oluchazwe yi-Equation (4):
Indawo yephuzu lapho ichopho le-vector yensimu kagesi lizocabanga khona linikezwe kuMfanekiso 5
Umfanekiso 5. Insimu kagesi yamagagasi e-elliptical polarization eqhubekayo. (4).
Insimu ekuFigure 5, ehamba ngendlela ephambene newashi, izoba yi-elliptical yesandla sokudla uma iphuma esikrinini. Uma i-vector yensimu kagesi ijikeleza ngendlela ephambene, insimu izohlukaniswa nge-elliptically yesandla sobunxele.
Ngaphezu kwalokho, i-elliptical polarization ibhekisela ekungavumelanini kwayo. Isilinganiso sokungavumelani nobukhulu be-amplitude yama-axes amakhulu namancane. Isibonelo, ukungavumelani kwamagagasi okuvela ku-equation (4) kungu-1/0.3 = 3.33. Amagagasi ahlukaniswe nge-elliptically achazwa kabanzi ngesiqondiso se-axis enkulu. I-wave equation (4) ine-axis equkethe ngokuyinhloko i-x-axis. Qaphela ukuthi i-axis enkulu ingaba kunoma iyiphi i-angle. I-angle ayidingeki ukuze ivumelane ne-axis X, Y noma Z. Okokugcina, kubalulekile ukuqaphela ukuthi kokubili i-polarization eyindilinga neqondile yizimo ezikhethekile ze-elliptical polarization. I-1.0 eccentric elliptically polarized wave iyigagasi elihlukaniswe nge-circularly polarized. Amagagasi ahlukaniswe nge-elliptically anokungavumelani okungenamkhawulo. Amagagasi ahlukaniswe nge-linearly.
Ukwehlukaniswa kwe-antenna
Manje njengoba sesiyazi ngamasimu kagesi e-polarized plane wave electromagnetic, i-polarization ye-antenna ichazwa kalula.
Ukuhlukaniswa kwe-Antenna Ukuhlolwa kwe-antenna ekude, ukuhlukaniswa kwensimu ekhishwa imisebe. Ngakho-ke, ama-antenna avame ukufakwa ohlwini "njengama-linearly polarized" noma "ama-antenna ahlukaniswe ngesandla sokudla".
Lo mqondo olula ubalulekile ekuxhumaneni kwe-antenna. Okokuqala, i-antenna evundlile ngokuvundlile ngeke ixhumane ne-antenna evundlile ngokuvundlile. Ngenxa ye-reciprocity theorem, i-antenna idlulisela futhi yamukele ngendlela efanayo. Ngakho-ke, ama-antenna avundlile ngokuvundlile adlulisela futhi amukele amasimu avundlile ngokuvundlile. Ngakho-ke, uma uzama ukudlulisa i-antenna evundlile ngokuvundlile ngokuvundlile, ngeke kube khona ukwamukelwa.
Esimweni esijwayelekile, kuma-antenna amabili aqondile ajikelezwe ngokuqondene nomunye nge-engeli ( ), ukulahlekelwa kwamandla ngenxa yalokhu kungafani kwe-polarization kuzochazwa yi-polarization loss factor (PLF):
Ngakho-ke, uma ama-antenna amabili ene-polarization efanayo, i-engeli ephakathi kwamasimu awo e-electron akhipha imisebe ayi-zero futhi akukho ukulahleka kwamandla ngenxa yokungafani kwe-polarization. Uma i-antenna eyodwa i-polarized ngokuqondile kanti enye i-polarized ngokuvundlile, i-engeli ingu-90 degrees, futhi akukho mandla azodluliselwa.
QAPHELA: Ukuhambisa ifoni phezu kwekhanda lakho ngezindlela ezahlukene kuchaza ukuthi kungani ukwamukela kungandiswa ngezinye izikhathi. Ama-antenna efoni avame ukuba ne-polarized linearly, ngakho-ke ukujikeleza ifoni kungahambisana ne-polarization yefoni, ngaleyo ndlela kuthuthukiswe ukwamukela.
I-polarization eyindilinga iyisici esifiselekayo sama-antenna amaningi. Womabili ama-antenna ahlukaniswe nge-polar futhi awahlushwa ukulahleka kwesiginali ngenxa yokungafani kwe-polarization. Ama-antenna asetshenziswa ezinhlelweni ze-GPS ahlukaniswe nge-polarized eyindilinga ngakwesokudla.
Manje ake sithi i-antenna eqondile ithola amaza aqondile ajikelezayo. Ngokufanayo, ake sithi i-antenna eqondile izama ukuthola amaza aqondile ajikelezayo. Iyini imbangela yokulahlekelwa yi-polarisation?
Khumbula ukuthi i-polarization eyindilinga empeleni ingamagagasi amabili aqondile ahlukaniswe ngomugqa, angama-degree angu-90 ngaphandle kwesigaba. Ngakho-ke, i-antenna ehlukaniswe ngomugqa (LP) izothola kuphela ingxenye yesigaba samagagasi ehlukaniswe ngomugqa (CP). Ngakho-ke, i-antenna ye-LP izoba nokulahlekelwa kokungafani kwe-polarization okungu-0.5 (-3dB). Lokhu kuyiqiniso kungakhathaliseki ukuthi i-antenna ye-LP ijikelezwe ngayiphi i-engeli. Ngakho-ke:
Isici sokulahlekelwa yi-polarization ngezinye izikhathi sibizwa ngokuthi ukusebenza kahle kwe-polarization, i-antenna mismatch factor, noma i-antenna reception factor. Wonke la magama abhekisela emqondweni ofanayo.
Isikhathi sokuthunyelwe: Disemba 22-2023
