Polarization yana ɗaya daga cikin manyan halayen eriya. Da farko muna buƙatar fahimtar polarization na raƙuman jirgin sama. Sannan za mu iya tattauna manyan nau'ikan polarization na eriya.
Rarrabuwar layi
Za mu fara fahimtar polarization na wani jirgin sama electromagnetic wave.
Raƙuman lantarki na planar (EM) suna da halaye da dama. Na farko shine cewa wutar lantarki tana tafiya a hanya ɗaya (babu wani canji a cikin alkibla biyu na orthogonal). Na biyu, filin lantarki da filin maganadisu suna tsaye da juna kuma suna tsaye da juna. Filin lantarki da maganadisu suna tsaye da alkiblar yaɗuwar raƙuman jirgin sama. Misali, yi la'akari da filin lantarki mai mita ɗaya (filin E) da aka bayar ta hanyar lissafi (1). Filin lantarki yana tafiya a alkiblar +z. Filin lantarki yana tafiya a alkiblar +x. Filin maganadisu yana cikin alkiblar +y.
A cikin lissafi (1), lura da alamar: . Wannan vector ne naúrar (vector na tsawon), wanda ke cewa wurin filin lantarki yana cikin alkiblar x. An kwatanta raƙuman jirgin sama a Hoto na 1.
Siffa ta 1. Zane-zanen filin lantarki yana tafiya a cikin alkiblar +z.
Polarization shine sifar da aka gano da kuma yaduwa (contour) na filin lantarki. Misali, yi la'akari da lissafin filin lantarki na raƙuman jirgin sama (1). Za mu lura da matsayin da filin lantarki yake (X,Y,Z) = (0,0,0) a matsayin aikin lokaci. An zana girman wannan filin a Hoto na 2, a lokuta da dama a lokaci. Filin yana juyawa a mita "F".
Siffa ta 2. Ka lura da filin lantarki (X, Y, Z) = (0,0,0) a lokuta daban-daban.
Ana lura da filin lantarki a asalinsa, yana juyawa baya da gaba a cikin girma. Filin lantarki koyaushe yana kan axis ɗin x da aka nuna. Tunda filin lantarki yana kiyaye shi a layi ɗaya, ana iya cewa wannan filin yana da layi ɗaya. Bugu da ƙari, idan axis ɗin X yana daidai da ƙasa, wannan filin kuma ana siffanta shi da layi ɗaya. Idan filin yana daidai da axis ɗin Y, za a iya cewa raƙuman suna da layi ɗaya ɗaya.
Ba a buƙatar a juya raƙuman da aka raba ta layi ɗaya ba tare da wata hanya ta kwance ko a tsaye. Misali, raƙuman filin lantarki tare da takura a kwance a layi kamar yadda aka nuna a Hoto na 3 suma za a raba su ta layi ɗaya.
hoto na 3. Girman filin lantarki na raƙuman ruwa masu layi-layi waɗanda hanyarsu ta kasance kusurwa.
Ana iya kwatanta filin lantarki a Hoto na 3 ta hanyar lissafi (2). Yanzu akwai ɓangaren x da y na filin lantarki. Dukansu sassan suna daidai da girma.
Abu ɗaya da za a lura da shi game da lissafi (2) shine xy-component da filayen lantarki a mataki na biyu. Wannan yana nufin cewa duka sassan suna da girman iri ɗaya a kowane lokaci.
zagaye polarization
Yanzu a ɗauka cewa an bayar da filin lantarki na raƙuman jirgin sama ta hanyar lissafi (3):
A wannan yanayin, abubuwan X- da Y sun fito daga mataki digiri 90. Idan aka lura da filin kamar (X, Y, Z) = (0,0,0) kamar yadda aka gani a da, filin lantarki da lanƙwasa lokaci zai bayyana kamar yadda aka nuna a ƙasa a Hoto na 4.
Hoto na 4. Ƙarfin filin lantarki (X, Y, Z) = (0,0,0) yankin EQ. (3).
Filin lantarki a cikin Hoto na 4 yana juyawa a cikin da'ira. An bayyana wannan nau'in filin a matsayin raƙuman da'ira mai rarrafe. Don rabawar da'ira, dole ne a cika waɗannan sharuɗɗa:
- Daidaitaccen tsari don rabuwar madauwari
- Dole ne filin lantarki ya ƙunshi sassa biyu na orthogonal (perpendicular).
- Dole ne sassan orthogonal na filin lantarki su kasance daidai girman.
- Dole ne sassan quadrature su kasance digiri 90 daga mataki.
Idan ana tafiya a kan allon Wave Figure 4, ana cewa juyawar filin tana akasin agogo kuma tana da zagaye mai siffar polarized na hannun dama (RHCP). Idan an juya filin a alkiblar agogo, filin zai zama polarization na hannun hagu (LHCP).
Rarrabuwar elliptical
Idan filin lantarki yana da sassa biyu masu layi biyu, digiri 90 daga mataki amma suna da girma iri ɗaya, filin zai kasance mai siffar elliptical. Idan aka yi la'akari da filin lantarki na raƙuman jirgin sama da ke tafiya a cikin alkiblar +z, wanda aka bayyana ta hanyar Lissafi (4):
An bayar da wurin da ƙarshen filin lantarki zai ɗauka a cikin Hoto na 5.
Hoto na 5. Filin lantarki mai saurin jujjuyawar elliptical. (4).
Filin da ke cikin Hoto na 5, wanda ke tafiya a akasin agogon agogo, zai kasance mai siffar elliptical na hannun dama idan yana tafiya daga allon. Idan na'urar lantarki ta juya a akasin haka, filin zai kasance mai siffar elliptical na hannun hagu.
Bugu da ƙari, rarrabuwar elliptical yana nufin daidaituwarsa. Rabon daidaituwa tsakanin girman manyan da ƙananan gatari. Misali, daidaituwa tsakanin raƙuman daga lissafi (4) shine 1/0.3= 3.33. An ƙara bayyana raƙuman da aka watsa ta hanyar karkatar da babban gatari. Lissafin raƙuman (4) yana da axis wanda ya ƙunshi axis na x. Lura cewa babban gatari na iya kasancewa a kowane kusurwar jirgin sama. Ba a buƙatar kusurwar don dacewa da axis na X, Y ko Z ba. A ƙarshe, yana da mahimmanci a lura cewa duka rabuwar zagaye da layi sune lokuta na musamman na rabuwar elliptical. 1.0 raƙuman da aka watsa ta elliptical mai watsawa ne mai watsawa da zagaye. raƙuman da aka watsa ta elliptical mai watsawa da iyaka. raƙuman da aka watsa ta layi.
Rarrabawar eriya
Yanzu da muka san filayen lantarki masu ratsa sararin samaniya masu ratsa sararin samaniya, kawai an bayyana rabuwar eriya.
Rarraba Eriya Kimantawa ta nesa ta eriya, rarrabuwar filin da aka samar da hasken da ya haifar. Saboda haka, sau da yawa ana jera eriya a matsayin "rarraba layi" ko "rarraba zagaye ta hannun dama".
Wannan ra'ayi mai sauƙi yana da mahimmanci ga sadarwa ta eriya. Da farko, eriya mai layi ɗaya a kwance ba za ta yi magana da eriya mai layi ɗaya a tsaye ba. Saboda ka'idar daidaitawa, eriya tana watsawa da karɓa ta hanya ɗaya. Saboda haka, eriya mai layi ɗaya a tsaye suna watsawa da karɓar filayen da aka layi ɗaya a tsaye. Saboda haka, idan ka yi ƙoƙarin isar da eriya mai layi ɗaya a tsaye a kwance, ba za a sami karɓa ba.
A cikin yanayin gabaɗaya, ga eriya biyu masu layi biyu masu juyewa waɗanda aka juya su dangane da juna ta kusurwa ( ), asarar wutar lantarki sakamakon wannan rashin daidaiton polarization za a bayyana ta hanyar rage asarar polarization (PLF):
Saboda haka, idan eriya biyu suna da polarization iri ɗaya, kusurwar da ke tsakanin filayen electrons ɗinsu masu haskakawa sifili ne kuma babu asarar wutar lantarki saboda rashin daidaiton polarization. Idan eriya ɗaya ta polarized a tsaye ɗaya kuma ta polarized a kwance, kusurwar tana digiri 90, kuma ba za a canja wutar lantarki ba.
LURA: Matsar da wayar a kan kanka zuwa kusurwoyi daban-daban yana bayanin dalilin da yasa ake iya ƙara karɓar waya a wasu lokutan. Eriya na wayar salula galibi suna da rassa a layi, don haka juyawar wayar sau da yawa na iya daidaita rassa na wayar, don haka inganta karɓar wayar.
Rarrabawar da'ira wata siffa ce mai kyau ga eriya da yawa. Duk eriya biyu suna da rarrabawar da'ira kuma ba sa fama da asarar sigina saboda rashin daidaiton rarrabawar. Eriya da ake amfani da su a tsarin GPS suna da rarrabawar da'ira ta hannun dama.
Yanzu a ɗauka cewa eriya mai layi-layi tana karɓar raƙuman da aka raba su da zagaye. Daidai da haka, a ɗauka cewa eriya mai layi-layi tana ƙoƙarin karɓar raƙuman da aka raba su da layi-layi. Menene dalilin asarar rabuwar da aka samu?
Ka tuna cewa rarrabawar zagaye a zahiri raƙuman ruwa ne guda biyu masu layi biyu na orthogonal, waɗanda digiri 90 suka wuce daga mataki. Saboda haka, eriya mai layi biyu (LP) za ta karɓi ɓangaren lokacin raƙuman ruwa mai zagaye (CP) ne kawai. Saboda haka, eriya ta LP za ta sami asarar rashin daidaiton rabuwar polarization na 0.5 (-3dB). Wannan gaskiya ne ko da wane kusurwa aka juya eriya ta LP. Saboda haka:
Ana kiran abin da ake kira Polarization loss factor a matsayin polarization efficiency, eriya mismatch factor, ko eriya reception factor. Duk waɗannan sunaye suna nufin ra'ayi ɗaya.
Lokacin Saƙo: Disamba-22-2023
