Gawo lothandiza powerengera mphamvu yolandila ya mlongoti ndimalo ogwira ntchitokapenapobowo wogwira mtima.Tangoganizani kuti mafunde a ndege omwe ali ndi polarization yofanana ndi mlongoti wolandila amachitika pa mlongoti.Kupitilira apo, lingalirani kuti mafundewa akuyenda molunjika ku mlongoti komwe kumalowera komwe kumawonekera kwambiri (komwe mphamvu zambiri zikadalandiridwa).
Kenako thepobowo wogwira mtimaparameter ikufotokoza kuchuluka kwa mphamvu zomwe zimatengedwa kuchokera ku mafunde a ndege.Tiyenipkukhala kachulukidwe mphamvu ya mafunde a ndege (mu W/m^2).NgatiP_timayimira mphamvu (mu Watts) pazipata za tinyanga zomwe zimapezeka kwa wolandila, ndiye:
Chifukwa chake, malo ogwira ntchito amangoyimira kuchuluka kwa mphamvu zomwe zimatengedwa kuchokera ku mafunde a ndege ndikuperekedwa ndi mlongoti.Derali limayambitsa zotayika zamkati mwa mlongoti (kutayika kwa ohmic, kutayika kwa dielectric, etc.).
Ubale wamba pakubowoko kogwira mtima malinga ndi kuchuluka kwa mlongoti (G) wa mlongoti uliwonse umaperekedwa ndi:
Pobowo mogwira mtima kapena malo ogwira mtima amatha kuyezedwa pa tinyanga zenizeni poyerekezera ndi mlongoti wodziwika wokhala ndi kabowo kothandiza, kapena powerengera pogwiritsa ntchito kupindula komwe kuyezedwa ndi equation yomwe ili pamwambapa.
Kutsegula kogwira mtima kudzakhala lingaliro lothandiza powerengera mphamvu zolandilidwa kuchokera ku mafunde a ndege.Kuti muwone izi zikugwira ntchito, pitani ku gawo lotsatira la njira yotumizira ya Friis.
The Friis Transmission Equation
Patsamba lino, tikuwonetsa chimodzi mwama equation ofunikira kwambiri mu chiphunzitso cha antenna, theFriis Transmission Equation.Friis Transmission Equation imagwiritsidwa ntchito kuwerengera mphamvu yolandilidwa kuchokera ku mlongoti umodzi (ndi phinduG1), ikatumizidwa kuchokera ku mlongoti wina (ndi phinduG2), olekanitsidwa ndi mtundaR, ndikugwira ntchito pafupipafupifkapena wavelength lambda.Tsambali ndiloyenera kuwerenga kangapo ndipo liyenera kumveka bwino.
Kuchokera kwa Friis Transmission Formula
Kuti muyambe kutengedwa kwa Friis Equation, lingalirani ma antennas awiri m'malo aulere (palibe zopinga pafupi) olekanitsidwa ndi mtunda.R:
Tangoganizani kuti (() Watts wa mphamvu zonse amaperekedwa ku mlongoti wotumizira.Pakadali pano, lingalirani kuti mlongoti wotumizira ndi wozungulira, wopanda kutayika, komanso kuti mlongoti wolandila uli kumtunda wakutali kwa mlongoti wotumizira.Ndiye kachulukidwe mphamvup(mu Watts pa lalikulu mita) ya zochitika za mafunde a ndege pa mlongoti wolandira mtundaRkuchokera ku transmit antenna imaperekedwa ndi:
Chithunzi 1. Kutumiza (Tx) ndi Kulandila (Rx) Antennas olekanitsidwa ndiR.
Ngati mlongoti wotumizira uli ndi kupindula kwa mlongoti wolandila woperekedwa ndi ( ） , ndiye kuti mphamvu ya kachulukidwe yamagetsi pamwambapa imakhala:
Nthawi yopindula imayambitsa kuwongolera ndi kutayika kwa mlongoti weniweni.Tangoganizani tsopano kuti mlongoti wolandirayo uli ndi pobowo yabwino yoperekedwa ndi( ）.Kenako mphamvu yolandilidwa ndi mlongoti ( ) imaperekedwa ndi:
Popeza kabowo kothandiza kwa mlongoti uliwonse kumatha kufotokozedwanso motere:
Mphamvu yolandirira zotsatira ikhoza kulembedwa motere:
Equation1
Izi zimadziwika kuti Friis Transmission Formula.Imakhudzana ndi kutayika kwa danga laulere, kupindula kwa tinyanga ndi kutalika kwa mafunde ku mphamvu zolandilidwa ndi kutumiza.Ichi ndi chimodzi mwama equations ofunikira mu chiphunzitso cha antenna, ndipo chiyenera kukumbukiridwa (komanso zomwe zachokera pamwambapa).
Mtundu wina wothandiza wa Friis Transmission Equation waperekedwa mu Equation [2].Popeza kutalika kwa mafunde ndi ma frequency f zimayenderana ndi liwiro la kuwala c (onani tsamba loyambira kufupipafupi), tili ndi Fomula Yopatsirana ya Friis malinga ndi pafupipafupi:
Equation2
Equation [2] ikuwonetsa kuti mphamvu zambiri zimatayika pama frequency apamwamba.Izi ndi zotsatira zoyambira za Friis Transmission Equation.Izi zikutanthauza kuti kwa ma antenna omwe ali ndi phindu lodziwika bwino, kutengera mphamvu kudzakhala kwakukulu pama frequency otsika.Kusiyana pakati pa mphamvu yolandilidwa ndi mphamvu yotumizidwa kumadziwika kuti kutayika kwa njira.Anati mwanjira ina, Friis Transmission Equation akuti kutayika kwa njira ndikokwera pamaulendo apamwamba.Kufunika kwa zotsatirazi kuchokera ku Friis Transmission Formula sikungathe kufotokozedwa mopambanitsa.Ichi ndichifukwa chake mafoni am'manja nthawi zambiri amagwira ntchito yochepera 2 GHz.Pakhoza kukhala ma frequency ochulukirapo omwe amapezeka pama frequency apamwamba, koma kutayika kogwirizanako sikungatheke kulandila bwino.Monga zotsatira zina za Friss Transmission Equation, tiyerekeze kuti mukufunsidwa za 60 GHz antennas.Pozindikira kuti ma frequency awa ndi okwera kwambiri, mutha kunena kuti kutayika kwa njira kudzakhala kokwera kwambiri kuti muzitha kulumikizana kwanthawi yayitali - ndipo mukulondola.Pamaulendo okwera kwambiri (60 GHz nthawi zina amatchedwa chigawo cha mm (millimeter wave)), kutayika kwa njira ndikokwera kwambiri, kotero kuti kulumikizana kolunjika kumatheka.Izi zimachitika pamene wolandira ndi wotumizira ali m'chipinda chimodzi, ndipo akuyang'anizana.Monga chowonjezera cha Friis Transmission Formula, kodi mukuganiza kuti ogwiritsa ntchito mafoni a m'manja ali okondwa ndi gulu latsopano la LTE (4G), lomwe limagwira ntchito pa 700MHz?Yankho ndi inde: uku ndi kutsika kwafupipafupi kusiyana ndi tinyanga zomwe zimagwirira ntchito, koma kuchokera ku Equation [2], tikuwona kuti kutayika kwa njira kudzakhalanso kotsika.Chifukwa chake, atha "kuphimba malo ochulukirapo" ndi ma frequency sipekitiramu, ndipo wamkulu wa Verizon Wireless posachedwapa adatcha "mawonekedwe apamwamba kwambiri", chifukwa chake.Zindikirani Pambali: Kumbali ina, opanga mafoni amayenera kuyika mlongoti wokhala ndi kutalika kokulirapo mu chipangizo chophatikizika (mafupipafupi otsika = utali wokulirapo), kotero kuti ntchito ya wopanga tinyangayo idakhala yovuta kwambiri!
Pomaliza, ngati tinyanga sizikufanana ndi polarization, mphamvu zomwe zalandilidwa pamwambapa zitha kuchulukitsidwa ndi Polarization Loss Factor (PLF) kuti ziwerengeredwe bwino pakusagwirizanaku.Equation [2] pamwambapa ikhoza kusinthidwa kuti ipange fomula yofananira ya Friis Transmission, yomwe imaphatikizapo kusagwirizana kwa polarization:
Equation3
Nthawi yotumiza: Jan-08-2024
