Kuwongolera ndi gawo lofunikira la antenna. Ichi ndi muyeso wa momwe mawonekedwe a radiation a antenna yolunjika alili. Antena yomwe imawulutsa mofanana mbali zonse idzakhala ndi kuwongolera kofanana ndi 1. (Izi ndizofanana ndi zero decibels -0 dB).
Ntchito ya ma coordinates ozungulira ingalembedwe ngati mawonekedwe a radiation okhazikika:
[Chiyerekezo 1]
Kapangidwe ka radiation yokhazikika kamakhala ndi mawonekedwe ofanana ndi kapangidwe koyambirira ka radiation. Kapangidwe ka radiation yokhazikika kamachepetsa kukula kwake kotero kuti mtengo wapamwamba wa kapangidwe ka radiation ndi wofanana ndi 1. (Yaikulu kwambiri ndi equation [1] ya "F"). Mwa masamu, njira yolunjika (mtundu "D") imalembedwa motere:
Izi zingawoneke ngati equation yovuta yolunjika. Komabe, mawonekedwe a ma radiation a mamolekyu ndi ofunika kwambiri. Denominator imayimira mphamvu yapakati yowulutsidwa mbali zonse. Equation ndiye muyeso wa mphamvu yapakati yowulutsidwa yogawidwa ndi avareji. Izi zimapangitsa kuti antenna itsogolere.
Njira yowongolera
Mwachitsanzo, taganizirani ma equation awiri otsatira a mawonekedwe a radiation a ma antenna awiri.
Antena 1
Antena 2
Mawonekedwe a ma radiation awa ajambulidwa mu Chithunzi 1. Chonde dziwani kuti mawonekedwe a ma radiation ndi ntchito ya polar angle theta(θ)Mawonekedwe a ma radiation si ntchito ya azimuth. (Mawonekedwe a azimuthal radiation sanasinthe). Mawonekedwe a ma radiation a antenna yoyamba ndi ochepa, kuposa mawonekedwe a ma radiation a antenna yachiwiri. Chifukwa chake, tikuyembekeza kuti ma direction a antenna yoyamba akhale otsika.
chithunzi 1. Chithunzi cha kapangidwe ka radiation ya antenna. Kodi ili ndi mayendedwe apamwamba?
Pogwiritsa ntchito fomula [1], titha kuwerengera kuti antenna ili ndi chitsogozo chapamwamba. Kuti muwone kumvetsetsa kwanu, ganizirani za Chithunzi 1 ndi komwe chitsogozo chili. Kenako dziwani kuti antenna iti yomwe ili ndi chitsogozo chapamwamba popanda kugwiritsa ntchito masamu.
Zotsatira za kuwerengera kolunjika, gwiritsani ntchito fomula [1]:
Kuwerengera kwa antenna yolunjika 1, 1.273 (1.05 dB).
Kuwerengera kwa antenna 2 yolunjika, 2.707 (4.32 dB).
Kuwongolera kwakukulu kumatanthauza kuti antenna yolunjika kwambiri kapena yolunjika. Izi zikutanthauza kuti antenna yolandira kawiri imakhala ndi mphamvu yolunjika nthawi 2.707 kuposa antenna yolunjika nthawi zonse. Antena 1 idzapeza mphamvu yolunjika nthawi 1.273 kuposa antenna yolunjika nthawi zonse. Ma antenna olunjika nthawi zonse amagwiritsidwa ntchito ngati njira yodziwika bwino ngakhale kuti palibe ma antenna a isotropic omwe alipo.
Ma antenna a foni ayenera kukhala ndi chitsogozo chochepa chifukwa zizindikiro zimatha kuchokera mbali iliyonse. Mosiyana ndi zimenezi, ma satellite dish amakhala ndi chitsogozo chapamwamba. Satellite dish imalandira zizindikiro kuchokera mbali yokhazikika. Mwachitsanzo, ngati mutapeza satellite TV dish, kampaniyo idzakuuzani komwe mungailoze ndipo mbaleyo idzalandira chizindikiro chomwe mukufuna.
Timaliza ndi mndandanda wa mitundu ya ma antenna ndi momwe amatsogolera. Izi zikupatsani lingaliro la momwe kulunjika kumakhalira kofala.
Mtundu wa Antena Kuwongolera kwapadera Kuwongolera kwapadera [decibel] (dB)
Antena ya dipole yaifupi 1.5 1.76
Antena ya dipole ya theka la mafunde 1.64 2.15
Chigamba (antenna ya microstrip) 3.2-6.3 5-8
Antena ya nyanga 10-100 10-20
Antena ya mbale 10-10,000 10-40
Monga momwe deta ili pamwambapa ikusonyezera, mayendedwe a antenna amasiyana kwambiri. Chifukwa chake, ndikofunikira kumvetsetsa mayendedwe posankha antenna yabwino kwambiri pa ntchito yanu. Ngati mukufuna kutumiza kapena kulandira mphamvu kuchokera mbali zosiyanasiyana mbali imodzi ndiye muyenera kupanga antenna yokhala ndi mayendedwe ochepa. Zitsanzo za mapulogalamu a antenna otsika ndi monga ma wailesi agalimoto, mafoni am'manja, ndi intaneti yopanda zingwe ya pakompyuta. Mosiyana ndi zimenezi, ngati mukuchita sensing yakutali kapena kusamutsa mphamvu mwachindunji, ndiye kuti antenna yolunjika kwambiri idzafunika. Ma antenna okwera kwambiri adzakulitsa kusamutsa mphamvu kuchokera mbali yomwe mukufuna ndikuchepetsa zizindikiro kuchokera mbali zomwe simukuzifuna.
Tiyerekeze kuti tikufuna antenna yotsika kwambiri. Kodi tingatani kuti tichite izi?
Lamulo lalikulu la chiphunzitso cha antenna ndilakuti mufunika antenna yaying'ono yamagetsi kuti mupange chitsogozo chochepa. Izi zikutanthauza kuti, ngati mugwiritsa ntchito antenna yokhala ndi kukula konse kwa mafunde a 0.25 - 0.5, ndiye kuti mudzachepetsa chitsogozo. Ma antenna a half-wave dipole kapena ma antenna a half-wavelength slot nthawi zambiri amakhala ndi chitsogozo chochepera 3 dB. Izi zimakhala zochepa ngati chitsogozo chomwe mungapeze pochita.
Pomaliza, sitingathe kupanga ma antenna kukhala ochepa kuposa kotala la mafunde popanda kuchepetsa mphamvu ya antenna ndi bandwidth ya antenna. Mphamvu ya ma antenna ndi bandwidth ya ma antenna zidzakambidwa m'mitu yotsatira.
Kuti tipeze antenna yokhala ndi mafunde amphamvu, tidzafunika ma antenna a kukula kosiyanasiyana kwa mafunde amphamvu. Monga ma antenna a satellite dish ndi ma antenna a horn ali ndi mafunde amphamvu kwambiri. Izi zili choncho chifukwa chakuti ali ndi mafunde amphamvu ambiri.
Chifukwa chiyani zili choncho? Pomaliza pake, chifukwa chake chikugwirizana ndi makhalidwe a Fourier transform. Mukatenga Fourier transform ya short pulse, mumapeza broad spectrum. Kufanizira kumeneku sikulipo podziwa momwe radiation imagwirira ntchito ya antenna. Ma radiation pattern amatha kuganiziridwa ngati Fourier transform ya kufalikira kwa mphamvu kapena magetsi motsatira antenna. Chifukwa chake, ma antenna ang'onoang'ono ali ndi ma radiation pattern akuluakulu (ndi ma directional otsika). Ma antenna okhala ndi voltage yayikulu kapena ma current distribution Ma models olunjika kwambiri (ndi ma directional apamwamba).
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Nthawi yotumizira: Novembala-07-2023
